Sensors for Robotic Hands: A Survey of State of the Art
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paper_title: A Method for the Control of Multigrasp Myoelectric Prosthetic Hands

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This paper presents the design and preliminary experimental validation of a multigrasp myoelectric controller. The described method enables direct and proportional control of multigrasp prosthetic hand motion among nine characteristic postures using two surface electromyography electrodes. To assess the efficacy of the control method, five nonamputee subjects utilized the multigrasp myoelectric controller to command the motion of a virtual prosthesis between random sequences of target hand postures in a series of experimental trials. For comparison, the same subjects also utilized a data glove, worn on their native hand, to command the motion of the virtual prosthesis for similar sequences of target postures during each trial. The time required to transition from posture to posture and the percentage of correctly completed transitions were evaluated to characterize the ability to control the virtual prosthesis using each method. The average overall transition times across all subjects were found to be 1.49 and 0.81 s for the multigrasp myoelectric controller and the native hand, respectively. The average transition completion rates for both were found to be the same (99.2%). Supplemental videos demonstrate the virtual prosthesis experiments, as well as a preliminary hardware implementation.
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paper_title: Performance characteristics of anthropomorphic prosthetic hands

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In this paper we set forth a review of performance characteristics for both common commercial prosthetics as well as anthropomorphic research devices. Based on these specifications as well as surveyed results from prosthetic users, ranges of hand attributes are evaluated and discussed. End user information is used to describe the performance requirements for prosthetic hands for clinical use.
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paper_title: Human Hand Function

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1. Historical Overview and general introduction 2. Evolutionary development and anatomy of the hand 3. Sensory neurophysiology 4. Tactile sensing 5. Active haptic sensing 6. Prehension 7. Non-prehensile skilled movements 8. End-effector constraints 9. Hand function across the lifespan 10. Applications 11. Summary, conclusions and future directions
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paper_title: The MANUS-HAND Dextrous Robotics Upper Limb Prosthesis: Mechanical and Manipulation Aspects

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Dextrous artificial hand design and manipulation is an active research topic. A very interesting practical application is the field of upper limb prosthetics. This paper presents the mechanical design and manipulation aspects of the MANUS-HAND project to develop a multifunctional upper limb prosthesis. The kinematics of our design makes use of the so-called underactuated principle and leads to an innovative design that triples the performance of currently existing commercial hand prosthesis. In addition, the thumb design allows its positioning both in flexion and opposition. As a consequence, up to four grasping modes (cylindrical, precision, hook and lateral) are available with just two actuators. ::: ::: The proposed impedance control approach allows the fingers to behave as virtual springs. Given the difficulty of including the user in the control loop, this approach is based on an autonomous coordination and control of the grasp. As a consequence, the requirements on the Human Machine interface are reduced. At the end of the paper, we briefly describe the clinical trials that were set up for evaluation purposes.
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paper_title: The evolution of functional hand replacement: From iron prostheses to hand transplantation.

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The hand is an integral component of the human body, with an incredible spectrum of functionality. In addition to possessing gross and fine motor capabilities essential for physical survival, the hand is fundamental to social conventions, enabling greeting, grooming, artistic expression and syntactical communication. The loss of one or both hands is, thus, a devastating experience, requiring significant psychological support and physical rehabilitation. The majority of hand amputations occur in working-age males, most commonly as a result of work-related trauma or as casualties sustained during combat. For millennia, humans have used state-of-the-art technology to design clever devices to facilitate the reintegration of hand amputees into society. The present article provides a historical overview of the progress in replacing a missing hand, from early iron hands intended primarily for use in battle, to today's standard body-powered and myoelectric prostheses, to revolutionary advancements in the restoration of sensorimotor control with targeted reinnervation and hand transplantation.
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paper_title: Functional Restoration of Adults and Children with Upper Extremity Amputation

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History of Arm Amputation, Prosthetic Restoration, and Arm Amputation Rehabilitation Surgical Aspects of Arm Amputation. Amputation Levels and Surgical Techniques Upper Extremity Salvage and Reconstruction for Trauma and Tumors Upper Extremity Amputation Revision and Reconstruction Surgical Options for Brachial Plexus Injury Comprehensive Management for the Arm Amputee. Rehabilitation Planning for the Upper Extremity Amputee Self-Determination of the Person with an Upper Extremity Amputation Integrating Psychological and Medical Care: Practice Recommendations for Amputation Pain Management for Upper Extremity Amputation Evaluation of the Adolescent and Adult with Upper Extremity Amputation The Prosthetist's Evaluation and Planning Process with the Upper Extremity Amputee Foot Skills and Other Alternatives to Hand-Use Postoperative and Preprosthetic Preparation Functional Skills Training with Body-Powered and Externally Powered Prostheses Prosthetic Restoration in Arm Amputation. Prosthetic Prescription Aesthetic Restorations for the Upper Limb Amputee Overview of Body-Powered Upper Extremity Prostheses Externally Powered Prostheses for the Adult Transradial and Wrist Disarticulation Amputee External-Power for the Transhumeral Amputee of Powered Upper Extremity Prostheses Creative Prosthetic Solutions for Bilateral Upper Extremity Amputation Prosthetic Rehabilitation of Glenohumeral Level Deficiencies Recreation and Sports Adaptations Case Studies of Upper Extremity Amputations and Prosthetic Restoration Pediatric Upper Extremity Amputation. Evaluation of a Child with Congenital Upper Extremity Limb Deficiency Training the Child with a Unilateral Upper-Extremity Prosthesis Pediatric Case Studies of Upper Extremity Limb Deficiencies Outcomes in Upper Extremity Amputation. Follow-up, Outcomes, and Long-term Experiences in Adults with Upper Extremity Amputation Return to Work Issues for the Upper Extremity Amputee Historical Trends and the Future. Research Trends for the 21st Century.
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paper_title: Android Hands: A State-of-the-Art Report

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Humans have adjusted their space, their actions, and their performed tasks according to their morphology, abilities, and limitations. Thus, the properties of a social robot should fit within these predetermined boundaries when, and if it is beneficial for the user, and the notion of the task. On such occasions, android and humanoid hand models should have similar structure, functions, and performance as the human hand. In this paper we present the anatomy, and the key functionalities of the human hand followed by a literature review on android/humanoid hands for grasping and manipulating objects, as well as prosthetic hands, in order to inform roboticists about the latest available technology, and assist their efforts to describe the state-of-the-art in this field.Copyright © 2014 by ASME
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paper_title: Results of an Internet survey of myoelectric prosthetic hand users

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The results of a survey of 54 persons with upper limb amputations who anonymously completed a questionnaire on an Internet homepage are presented. The survey ran for four years and the participants were divided into groups of females, males, and children. It was found that the most individuals employ their myoelectric hand prosthesis for 8 hours or more. However, the survey also revealed a high level of dissatisfaction with the weight and the grasping speed of the devices. Activities for which prostheses should be useful were stated to include handicrafts, personal hygiene, using cutlery, operation of electronic and domestic devices, and dressing/undressing. Moreover, additional functions, e.g., a force feedback system, independent movements of the thumb, the index finger, and the wrist, and a better glove material are priorities that were identified by the users as being important improvements the users would like to see in myoelectric prostheses.
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paper_title: Paré and prosthetics: the early history of artificial limbs.

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There is evidence for the use of prostheses from the times of the ancient Egyptians. Prostheses were developed for function, cosmetic appearance and a psycho-spiritual sense of wholeness. Amputation was often feared more than death in some cultures. It was believed that it not only affected the amputee on earth, but also in the afterlife. The ablated limbs were buried and then disinterred and reburied at the time of the amputee's death so the amputee could be whole for eternal life. One of the earliest examples comes from the 18th dynasty of ancient Egypt in the reign of Amenhotep II in the fifteenth century bc. A mummy in the Cairo Museum has clearly had the great toe of the right foot amputated and replaced with a prosthesis manufactured from leather and wood. The first true rehabilitation aids that could be recognized as prostheses were made during the civilizations of Greece and Rome. During the Dark Ages prostheses for battle and hiding deformity were heavy, crude devices made of available materials - wood, metal and leather. Such were the materials available to Ambroise Paré who invented both upper-limb and lower-limb prostheses. His 'Le Petit Lorrain', a mechanical hand operated by catches and springs, was worn by a French Army captain in battle. Subsequent refinements in medicine, surgery and prosthetic science greatly improved amputation surgery and the function of prostheses. What began as a modified crutch with a wooden or leather cup and progressed through many metamorphoses has now developed into a highly sophisticated prosthetic limb made of space-age materials.
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paper_title: The Sensory Somatotopic Map of the Human Hand Demonstrated at 4 Tesla

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Abstract Recent attempts at high-resolution sensory-stimulated fMRI performed at 1.5 T have had very limited success at demonstrating a somatotopic organization for individual digits. Our purpose was to determine if functional MRI at 4 T can demonstrate the sensory somatotopic map of the human hand. Sensory functional MRI was performed at 4 T in five normal volunteers using a low-frequency vibratory stimulus on the pad of each finger of the left hand. A simple motor control task was also performed. The data were normalized to a standard atlas, and individual and group statistical parametric maps (SPMs) were computed for each task. Volume of activation and distribution of cluster maxima were compared for each task. For three of the subjects, the SPMs demonstrated a somatotopic organization of the sensory cortex. The group SPMs demonstrated a clear somatotopic organization of the sensory cortex. The thumb to fifth finger were organized, in general, with a lateral to medial, inferior to superior, and anterior to posterior relationship. There was overlap in the individual SPMs between fingers. The sensory activation spanned a space of 12–18 mm (thumb to fifth finger) on the primary sensory cortex. The motor activation occurred consistently at the superior-most extent of the sensory activation within and across subjects. The sensory somatotopic map of the human hand can be identified at 4 T. High-resolution imaging at 4 T can be useful for detailed functional imaging studies.
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paper_title: Robot Evolution: The Development of Anthrobotics

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From the Publisher: ::: Since the creation of the first modern robots in the 1950s, robotics has developed rapidly and in diverse directions; the term robot (from the Czech word for drudgery) now applies to a spectrum of creations, from mechanical limbs bolted to factory floors to computer-driven bipeds with human-like capabilities. But the urge to create "mechanical men" to perform mundane, repetitive, and even complex human tasks is nearly as old as civilization itself. The ancient Greeks built automata, as did the Egyptians and the Japanese. Leonardo da Vinci designed mechanical men, and entertainment robots were all the rage in eighteenth-century Europe. Robot Evolution is unique in robotics literature, at once a comprehensive pictorial history of robots and a technical guide to robot designs, devices, and systems. Author and robot expert Mark E. Rosheim reviews and describes the gamut of robot mechanisms, from ancient to state-of-the-art, from subcomponents such as joints, grippers, and actuators to completely integrated systems equipped with artificial intelligence, sensors, and autonomous mobility. Rosheim chronicles the development and increasing complexity of these systems, using the kinesiology of human body parts as a framework for evaluating the kinematics of robotic components and explaining how these components are used to emulate human motion. Particular emphasis is placed on the most advanced current devices and promising experimental designs. Supplemented with hundreds of photographs, drawings, and illustrated tables, Robot Evolution is written in a clear, forthright style and organized to provide quick and easy access to information. Separate chapters are devoted to robot arms, wrists, hands, and legs, and each chapter contains examples of several different design approaches to the same problem or component. The advantages and disadvantages of each design are discussed in detail along with preferred applications and specific functions of each device. An annotated bib
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paper_title: Tactile Sensing—From Humans to Humanoids

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Starting from human ?sense of touch,? this paper reviews the state of tactile sensing in robotics. The physiology, coding, and transferring tactile data and perceptual importance of the ?sense of touch? in humans are discussed. Following this, a number of design hints derived for robotic tactile sensing are presented. Various technologies and transduction methods used to improve the touch sense capability of robots are presented. Tactile sensing, focused to fingertips and hands until past decade or so, has now been extended to whole body, even though many issues remain open. Trend and methods to develop tactile sensing arrays for various body sites are presented. Finally, various system issues that keep tactile sensing away from widespread utility are discussed.
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paper_title: The selection of mechanical actuators based on performance indices

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A method is presented for selecting the type of actuator best suited to a given task, in the early stages of engineering design. The selection is based on matching performance characteristics of the actuator, such as force and displacement, to the requirements of the given task. The performance characteristics are estimated from manufacturers9 data and from simple models of performance limitation such as heat generation and resonance. Characteristics are presented in a graphical form which allows for a direct and systematic comparison of widely different systems of actuation. The actuators considered include man-made actuators (such as hydraulic, solenoid and shape memory alloy) and naturally occurring actuators (such as the muscles of animals and plants).
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paper_title: Hands for Dexterous Manipulation and Robust Grasping: A Difficult Road Towards Simplicity

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In this paper, an attempt at summarizing the evolution and the state of the art in the field of robot hands is made. In such exposition, a critical evaluation of what in the author's view are the leading ideas and emerging trends is privileged with respect to exhaustiveness of citations. The survey is focused mainly on three types of functional requirements a machine hand can be assigned in an artificial system, namely, manipulative dexterity, grasp robustness, and human operability. A basic distinction is made between hands designed for mimicking the human anatomy and physiology,and hands designed to meet restricted, practical requirements. In the latter domain, arguments are presented in favor of a -minimalistic" attitude in the design of hands for practical applications, i.e., use the least number of actuators, the simplest set of sensors, etc., for a given task. To achieve this rather obvious engineering goal is a challenge to our community. The paper illustrates some of the new sometimes difficult, problems that are brought about by building and controlling simpler, more practical devices.
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paper_title: Hands for Dexterous Manipulation and Robust Grasping: A Difficult Road Towards Simplicity

paper_content:

In this paper, an attempt at summarizing the evolution and the state of the art in the field of robot hands is made. In such exposition, a critical evaluation of what in the author's view are the leading ideas and emerging trends is privileged with respect to exhaustiveness of citations. The survey is focused mainly on three types of functional requirements a machine hand can be assigned in an artificial system, namely, manipulative dexterity, grasp robustness, and human operability. A basic distinction is made between hands designed for mimicking the human anatomy and physiology,and hands designed to meet restricted, practical requirements. In the latter domain, arguments are presented in favor of a -minimalistic" attitude in the design of hands for practical applications, i.e., use the least number of actuators, the simplest set of sensors, etc., for a given task. To achieve this rather obvious engineering goal is a challenge to our community. The paper illustrates some of the new sometimes difficult, problems that are brought about by building and controlling simpler, more practical devices.
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paper_title: Sensory motor systems of artificial and natural hands

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The surgeon Ambroise Paré designed an anthropomorphic hand for wounded soldiers in the 16th century. Since that time, there have been advances in technology through the use of computer-aided design, modern materials, electronic controllers and sensors to realise artificial hands which have good functionality and reliability. Data from touch, object slip, finger position and temperature sensors, mounted in the fingers and on the palm, can be used in feedback loops to automatically hold objects. A study of the natural neuromuscular systems reveals a complexity which can only in part be realised today with technology. Highlights of the parallels and differences between natural and artificial hands are discussed with reference to the Southampton Hand. The anatomical structure of parts of the natural systems can be made artificially such as the antagonist muscles using tendons. Theses solutions look promising as they are based on the natural form but in practice lack the desired physical specification. However, concepts of the lower spinal loops can be mimicked in principle. Some future devices will require greater skills from the surgeon to create the interface between the natural system and an artificial device. Such developments may offer a more natural control with ease of use for the limb deficient person.
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paper_title: Effective emotional expressions with expression humanoid robot WE-4RII: integration of humanoid robot hand RCH-1

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The authors have been developing humanoid robots in order to develop new mechanisms and functions for a humanoid robot that has the ability to communicate naturally with a human by expressing human-like emotion. We considered that human hands play an important role in communication because human hands have grasping, sensing and emotional expression abilities. Then, we developed the emotion expression humanoid robot WE-4RII (Waseda Eye No.4 Refined II) by integrating the new humanoid robot hands RCH-1 (RoboCasa Hand No.1) into the emotion expression humanoid robot WE-4R. Furthermore, we confirmed that RCH-1 and WE-4RII had effective emotional expression ability because the correct recognition rate of WE-4RII's emotional expressions was higher than the WE-4R's one. In this paper, we describe the mechanical features of WE-4RII.
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paper_title: Experimental analysis and performance comparison of three different prosthetic hands designed according to a biomechatronic approach

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Three different artificial hands have been designed in the framework of collaboration between the INAIL/RTR Centre and the Arts of Lab of Scuola Superiore Sant'Anna (SSSA) with the aim of developing a novel generation of prosthetic hands with increasing performance in restoring grasping functionalities in case of hand amputation. After having illustrated the philosophy and the methods of the biomechatronic approach to the design of prosthetic devices, the three different artificial hand prototypes are presented and described. A novel experimental protocol to assess hand performance has been conceived in order to provide quantitative parameters to analyze and compare various hands. The most important physical quantities to be rigorously measured and compared are the forces exerted on the object in different locations on the hand and in different grasping conditions. In particular, the test protocol is composed of six different experimental tests intended to measure the grasping force during the precision grip, the power grasp and the lateral pinch. The results obtained by applying the test protocol to the three prototypes are presented and discussed. In conclusion the paper presents the specifications of a novel prosthetic hand coming out from analysis presented in this paper.
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paper_title: The MANUS-HAND Dextrous Robotics Upper Limb Prosthesis: Mechanical and Manipulation Aspects

paper_content:

Dextrous artificial hand design and manipulation is an active research topic. A very interesting practical application is the field of upper limb prosthetics. This paper presents the mechanical design and manipulation aspects of the MANUS-HAND project to develop a multifunctional upper limb prosthesis. The kinematics of our design makes use of the so-called underactuated principle and leads to an innovative design that triples the performance of currently existing commercial hand prosthesis. In addition, the thumb design allows its positioning both in flexion and opposition. As a consequence, up to four grasping modes (cylindrical, precision, hook and lateral) are available with just two actuators. ::: ::: The proposed impedance control approach allows the fingers to behave as virtual springs. Given the difficulty of including the user in the control loop, this approach is based on an autonomous coordination and control of the grasp. As a consequence, the requirements on the Human Machine interface are reduced. At the end of the paper, we briefly describe the clinical trials that were set up for evaluation purposes.
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paper_title: The Cyberhand: on the design of a cybernetic prosthetic hand intended to be interfaced to the peripheral nervous system

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The objective of the project described in this paper is the development of a cybernetic prosthesis, replicating as much as possible the sensory-motor capabilities of the natural hand. The human hand is not only an effective tool but also an ideal instrument to acquire information from the external environment. The development of a truly human-like artificial hand is probably the most widely known paradigm of "bionics". The Cyberhand Project aims to obtain a cybernetic prosthetic hand interfaced to the peripheral nervous system. In particular this paper is focused on the hand mechanisms design and it presents preliminary results in developing the three fingered anthropomorphic hand prototype and its sensory system.
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paper_title: Development and Control of a Multifunctional Prosthetic Hand with Shape Memory Alloy Actuators

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In this research paper, non-conventional actuation technology, based on shape memory alloys, is employed for the development of an innovative low-cost five-fingered prosthetic hand. By exploiting the unique properties of these alloys, a compact, silent and modular actuation system is implemented and integrated in a lightweight and anthropomorphic rapid-prototyped hand chassis. A tendon-driven underactuated mechanism provides the necessary dexterity while keeping the mechanical and control complexity of the device low. Tactile sensors are integrated in the fingertips improving the overall hand control. Embedded custom-made electronics for hand interfacing and control are also presented and analyzed. For the position control of each digit, a novel resistance feedback control scheme is devised and implemented. The functionality and performance of the developed hand is demonstrated in grasp experiments with common objects.When compared to the current most advanced commercial devices, the technology applied in this prototype provides a series of improvements in terms of size, weight, and noise, which will enable upper limb amputees to carry out their basic daily tasks more comfortably.
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paper_title: Thick-film force and slip sensors for a prosthetic hand

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In an attempt to improve the functionality of a prosthetic hand device, a new fingertip has been developed that incorporates sensors to measure temperature and grip force, and to detect the onset of object slip from the hand. The sensors have been implemented using thick film printing technology and exploit the piezoresistive characteristics of commercially available screen printing resistive pastes and the piezoelectric properties of proprietary lead-zirconate-titanate (PZT) formulated pastes. This paper describes the design and production of these different types of sensor and presents some results from initial investigations.
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paper_title: The SPRING Hand: Development of a Self-Adaptive Prosthesis for Restoring Natural Grasping

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Commercially available prosthetic hands are simple grippers with one or two degrees of freedom; these pinch type devices have two rigid fingers in opposition to a rigid thumb. This paper focuses on an innovative approach for the design of a myoelectric prosthetic hand. The new prosthesis features underactuated mechanisms in order to achieve a natural grasping behavior and a good distribution of pinching forces. In this paper it is shown that underactuation allows reproducing most of the grasping behaviors of the human hand, without augmenting the mechanical and control complexity.
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paper_title: Artificial Redirection of Sensation From Prosthetic Fingers to the Phantom Hand Map on Transradial Amputees: Vibrotactile Versus Mechanotactile Sensory Feedback

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This work assesses the ability of transradial amputees to discriminate multi-site tactile stimuli in sensory discrimination tasks. It compares different sensory feedback modalities using an artificial hand prosthesis in: 1) a modality matched paradigm where pressure recorded on the five fingertips of the hand was fed back as pressure stimulation on five target points on the residual limb; and 2) a modality mismatched paradigm where the pressures were transformed into mechanical vibrations and fed back. Eight transradial amputees took part in the study and were divided in two groups based on the integrity of their phantom map; group A had a complete phantom map on the residual limb whereas group B had an incomplete or nonexisting map. The ability in localizing stimuli was compared with that of 10 healthy subjects using the vibration feedback and 11 healthy subjects using the pressure feedback (in a previous study), on their forearms, in similar experiments. Results demonstrate that pressure stimulation surpassed vibrotactile stimulation in multi-site sensory feedback discrimination. Furthermore, we demonstrate that subjects with a detailed phantom map had the best discrimination performance and even surpassed healthy participants for both feedback paradigms whereas group B had the worst performance overall. Finally, we show that placement of feedback devices on a complete phantom map improves multi-site sensory feedback discrimination, independently of the feedback modality.
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paper_title: Intelligent multifunction myoelectric control of hand prostheses.

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Intuitive myoelectric prosthesis control is difficult to achieve due to the absence of proprioceptive feedback, which forces the user to monitor grip pressure by visual information. Existing myoelectric hand prostheses form a single degree of freedom pincer motion that inhibits the stable prehension of a range of objects. Multi-axis hands may address this lack of functionality, but as with multifunction devices in general, serve to increase the cognitive burden on the user. Intelligent hierarchical control of multiple degree-of-freedom hand prostheses has been used to reduce the need for visual feedback by automating the grasping process. This paper presents a hybrid controller that has been developed to enable different prehensile functions to be initiated directly from the user's myoelectric signal. A digital signal processor (DSP) regulates the grip pressure of a new six-degree-of-freedom hand prosthesis thereby ensuring secure prehension without continuous visual feedback.
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paper_title: Design and development of an underactuated prosthetic hand

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Current prosthetic hands are basically simple grippers with one or two degrees of freedom, which barely restore the capability of the thumb-index pinch. Although most amputees consider this performance as acceptable for usual tasks, there is ample room for improvement by exploiting recent progresses in mechatronic design and technology. This paper focus on an innovative approach for the design and development of prosthetic hands based on underactuated mechanisms. Furthermore, it describes the development and a preliminary analysis of a first prototype of an underactuated prosthetic hand.
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paper_title: A Flexible High Resolution Tactile Imager with Video Signal Output.

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A high resolution and sheetlike form imaging tactile sensor with video signal output has been developed. The sensor has a 64×64 array of sensing elements on a flexible PC board with 1mm spatial resolution. Since the sensor outputs pressure distribution as a video signal, real time tactile image can be observed by using TV monitor. Moreover the same hardware and software of a vision system can be used for measured data handlings, tactile image processing and recording are very simple. As the sensor is made up of a sheet of pressure conductive rubber and stripe electrodes, there are undesiable current passes between sensing elements. Thus these undesiable current passes must be cut within a short scanning priod (500 ns for each element). We used a ground potential method and proved it useful under such a high speed scanning condition. The properties of pressure conductive rubber, including hysteresis and creap effects, are presented. A spatial filtering effect of an elastic cover for a tactile sensor is also analyzed. And it is proved this effect is very important. The final section shows measured data and image processing examples.
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paper_title: Multiple finger, passive adaptive grasp prosthetic hand

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Abstract This paper describes the mechanical features of an experimental, multiple finger, prosthetic hand which has been designed for children in the 7–11 year age group. Conventional prosthetic hands exist for this age group, but they have limited mechanical function. The experimental hand presented is able to perform passive adaptive grasp, that is, the ability of the fingers to conform to the shape of an object held within the hand. During grasping, the four fingers and thumb are able to flex inwards independently, to conform to the shape of the object. This passive design is simple and effective, not requiring sensors or electronic processing. The adaptive grasp system developed here results in a hand with reduced size and weight compared to other experimental hands, and has increased mechanical function and cosmetic appearance compared to conventional prosthetic hands.
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paper_title: The DEKA Arm: Its features, functionality, and evolution during the Veterans Affairs Study to optimize the DEKA Arm

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BACKGROUND AND AIM ::: DEKA Integrated Solutions Corp. (DEKA) was charged by the Defense Advanced Research Project Agency to design a prosthetic arm system that would be a dramatic improvement compared with the existing state of the art. The purpose of this article is to describe the two DEKA Arm prototypes (Gen 2 and Gen 3) used in the Veterans Affairs Study to optimize the DEKA Arm. ::: ::: ::: TECHNIQUE ::: This article reports on the features and functionality of the Gen 2 and Gen 3 prototypes discussing weight, cosmesis, grips, powered movements Endpoint, prosthetic controls, prosthetist interface, power sources, user notifications, troubleshooting, and specialized socket features; pointing out changes made during the optimization efforts. ::: ::: ::: DISCUSSION ::: The DEKA Arm is available in three configurations: radial configuration, humeral configuration, and shoulder configuration. All configurations have six preprogrammed grip patterns and four wrist movements. The humeral configuration has four powered elbow movements. The shoulder configuration uses Endpoint Control to perform simultaneous multi-joint movements. Three versions of foot controls were used as inputs. The Gen 3 incorporated major design changes, including a compound wrist that combined radial deviation with wrist flexion and ulnar deviation with wrist extension, an internal battery for the humeral configuration and shoulder configuration, and embedded wrist display. ::: ::: ::: CLINICAL RELEVANCE ::: The DEKA Arm is an advanced upper limb prosthesis, not yet available for commercial use. It has functionality that surpasses currently available technology. This manuscript describes the features and functionality of two prototypes of the DEKA Arm, the Gen 2 and the Gen 3.
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paper_title: Restoring Natural Sensory Feedback in Real-Time Bidirectional Hand Prostheses

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Hand loss is a highly disabling event that markedly affects the quality of life. To achieve a close to natural replacement for the lost hand, the user should be provided with the rich sensations that we naturally perceive when grasping or manipulating an object. Ideal bidirectional hand prostheses should involve both a reliable decoding of the user's intentions and the delivery of nearly "natural" sensory feedback through remnant afferent pathways, simultaneously and in real time. However, current hand prostheses fail to achieve these requirements, particularly because they lack any sensory feedback. We show that by stimulating the median and ulnar nerve fascicles using transversal multichannel intrafascicular electrodes, according to the information provided by the artificial sensors from a hand prosthesis, physiologically appropriate (near-natural) sensory information can be provided to an amputee during the real-time decoding of different grasping tasks to control a dexterous hand prosthesis. This feedback enabled the participant to effectively modulate the grasping force of the prosthesis with no visual or auditory feedback. Three different force levels were distinguished and consistently used by the subject. The results also demonstrate that a high complexity of perception can be obtained, allowing the subject to identify the stiffness and shape of three different objects by exploiting different characteristics of the elicited sensations. This approach could improve the efficacy and "life-like" quality of hand prostheses, resulting in a keystone strategy for the near-natural replacement of missing hands.
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paper_title: A control system for multi-fingered robotic hand with distributed touch sensor

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A robotic hand and its control system is developed. This hand has five fingers and 22 DOF. (16 for fingers and 6 for arm). The surface of the hand is covered with a distributed touch sensor that has more than 500 measuring points. This system, can control the positon, orientation, velocity and force of multiple points on the hand simultaneously. The effectiveness of this system is shown by the experiment in which the robotic hand holds a pair of scissors and achieves a paper cutting task. The event driven task execution system is also developed and used for the experiment. This system, watches the event which signals the change of the constrained state of the hand and switches the control points and their behaviors on the hand dynamically according to the detected event.
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paper_title: Design of the TUAT/Karlsruhe humanoid hand

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The increasing demand for robotic applications in dynamic unstructured environments is motivating the need for dextrous end-effectors which can cope with the wide variety of tasks and objects encountered in these environments. The human hand is a very complex grasping tool that can handle objects of different sizes and shapes. Many research activities have been carried out to develop artificial robot hands with capabilities similar to the human hand. In this paper the mechanism and design of a new humanoid-type hand (called TUAT/Karlsruhe Humanoid Hand) with human-like manipulation abilities is discussed. The new hand is designed for the humanoid robot ARMAR which has to work autonomously or interactively in cooperation with humans and for an artificial lightweight arm for handicapped persons. The arm is developed as close as possible to the human arm and is driven by spherical ultrasonic motors. The ideal end-effector for such an artificial arm or a humanoid would be able to use the tools and objects that a person uses when working in the same environment. Therefore a new hand is designed for anatomical consistency with the human hand. This includes the number of fingers and the placement and motion of the thumb, the proportions of the link lengths and the shape of the palm. It can also perform most part of human grasping types. The TUAT/Karlsruhe Humanoid Hand possesses 20 DOF and is driven by one actuator which can be placed into or around the hand.
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paper_title: Development of a lightweight and adaptable multiple-axis hand prosthesis.

paper_content:

The last few decades have produced significant improvements in the design of upper limb prostheses through the increasing use of technology. However the limited function exhibited by these devices remains rooted in their single degree of freedom format. Commercial myoelectric hand prostheses warrant high grip forces to ensure stable prehension due to a planar pincer movement. Hence precise and conscious effort is required on the part of the user to ensure optimum grip. Consumers have shown dissatisfaction with the status quo due to the excessive weight and poor function of existing artificial hands. Increasing the number of grasping patterns and improving the visual feedback from an object in the hand are cited as key objectives. This paper outlines the development of the six-axis Southampton-Remedi hand prosthesis that addresses these design issues by maintaining stable prehension with minimal grip force. Constraints such as modularity, anthropomorphism, and low weight and power consumption are factors that have been adhered to throughout the design process.
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paper_title: The development of soft gripper for the versatile robot hand

paper_content:

Abstract This paper deals with a new type of soft gripper which can softly and gently conform to objects of any shape and hold them with uniform pressure. This gripping function is realized by means of a mechanism consisting of multi-links and series of pulleys which can be simply actuated by a pair of wires. The possibilities of this gripper are demonstrated by a pair of mechanical model.
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paper_title: The SmartHand transradial prosthesis

paper_content:

Background ::: Prosthetic components and control interfaces for upper limb amputees have barely changed in the past 40 years. Many transradial prostheses have been developed in the past, nonetheless most of them would be inappropriate if/when a large bandwidth human-machine interface for control and perception would be available, due to either their limited (or inexistent) sensorization or limited dexterity. SmartHand tackles this issue as is meant to be clinically experimented in amputees employing different neuro-interfaces, in order to investigate their effectiveness. This paper presents the design and on bench evaluation of the SmartHand.
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paper_title: Design of a Multigrasp Transradial Prosthesis

paper_content:

This paper describes the design and performance of a new prosthetic hand capable of multiple grasp configurations, and capable of fingertip forces and speeds comparable to those used by healthy subjects in typical activities of daily living. The hand incorporates four motor units within the palm, which together drive sixteen joints through tendon actuation. Each motor unit consists of a brushless motor that drives one or more tendons through a custom two-way clutch and pulley assembly. After presenting the design of the prosthesis, the paper presents a characterization of the hand's performance. This includes its ability to provide eight grasp postures, as well as its ability to provide fingertip forces and finger speeds comparable to those described in the biomechanics literature corresponding to activities of daily living.
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paper_title: UBH 3: an anthropomorphic hand with simplified endo-skeletal structure and soft continuous fingerpads

paper_content:

The paper describes work in progress at the University of Bologna concerning the design of a new anthropomorphic robot hand. The hand is based on the modular assembly of articulated fingers that adopt an original configuration of their structure, made with rigid links connected by elastic hinges that are coaxially crossed by flexible tendons. This innovative design is suitable to host distributed sensory equipment and continuous compliant cover, allowing a high level of anthropomorphism together with great structural simplification, reliability enhancement and cost reduction. Furthermore, the proposed solution is very flexible, as it can be adapted to many different hand configurations and is not dependent on a particular type of actuation, being compatible with future availability of any kind of artificial muscles.
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paper_title: Developments of new anthropomorphic robot hand and its master slave system

paper_content:

This paper presents a newly developed anthropomorphic robot hand called KH Hand type S, which has high potential of dexterous manipulation and displaying hand shape, and its master slave system using the bilateral controller for five-fingers robot hand. The robot hand is improved by reducing the weight, the backlash of transmission, and the friction between gears by using elastic body. Expression of Japanese finger alphabet is shown. In order to demonstrate the dexterous grasping and manipulating an object, the experiment of peg-in-hole task controlled by bilateral controller is shown. These results denote that the KH Hand type S has a high potential to perform dexterous object manipulation like the human hand.
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paper_title: Optoelectronic joint angular sensor for robotic fingers

paper_content:

The present paper reports the results of the development of a novel joint angular sensor conceived for integration in tendon-driven robotic hands and in data gloves used in virtual reality systems. The sensor is based on a couple LED/photodiode, mounted to two contiguous phalanges of a University of Bologna (UB) hand finger. When the joint between the considered phalanges flexes, the photocurrent measured by the photodetector changes with the angular displacement. An experimental model of the sensor is set up in order to select the optimal positioning of the components over the phalanges and an optical motion capture system is used to calibrate the sensor. The complete characterization of the sensor in terms of repeatability, linearity and noise presented in the paper together with its low cost confirm that the sensor can be effectively exploited both in feedback control loops for robotic systems as well as in data acquisition systems for virtual reality applications.
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paper_title: Shape classification in rotation manipulation by universal robot hand

paper_content:

We propose a method for shape classification in continuous rotation manipulation by a multi-fingered robot hand. Our robot hand has five fingers equipped with tactile sensors. Each tactile sensor can measure a pressure distribution once every 10(ms) while the robot hand rotates the object continuously. Our proposed classification method consists of the following processes: A kurtosis is calculated from each pressure distribution, and it quantifies shape of the current contact surface. By rotating an object and measuring a time-series pressure distribution, the hand obtains a time-series kurtosis. Finally, a evaluated value is calculated between the time-series kurtosis and reference patterns through a continuous dynamic programming (CDP) matching scheme. The contact shape is classified if the evaluated value is lower than a threshold. We show the effectiveness of our method through experiments.
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paper_title: DLR hand II: experiments and experience with an anthropomorphic hand

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At our institute, two generations of antropomorphic hands have been designed. In quite a few experiments and demonstrations we could show the abilities of our hands and gain a lot of experience in what artificial hands can do, what abilities they need and where their limitations lie. In this paper, we would like to give an overview over the experiments performed with the DLR hands, our hands abilities and the things that need to be done in the near future.
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paper_title: Door opening control using the multi-fingered robotic hand for the indoor service robot

paper_content:

KIST service robot is composed of a mobile platform, a 6 DOF robotic manipulator, and a multi-fingered robotic hand. We discuss motion control and coordination strategy in order to deal with uncertainty problem in practical applications. A door opening is our target task. Since the environment is not prepared for a service robot, it is essential to deal with various uncertainties due to a robot positioning error, sensing error, as well as manipulation errors. In this paper, practical parameter estimation schemes are proposed from the viewpoint of coordinative motion control of a hand, a manipulator and a mobile robot. Analysis of physical properties of each component provides a methodology of appropriate role assignment for each component. In order to carrying out compliance control, an external force is computed using fingertip force information of the three fingered robot hand, instead of using force torque sensor at the wrist. Presented experimental result clearly shows the effectiveness of the proposed scheme.
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paper_title: Force/tactile sensor for robotic applications

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Abstract The paper describes the detailed design and the prototype characterization of a novel tactile sensor 1 for robotic applications. The sensor is based on a two-layer structure, i.e. a printed circuit board with optoelectronic components below a deformable silicon layer with a suitably designed geometry. The mechanical structure of the sensor has been optimized in terms of geometry and material physical properties to provide the sensor with different capabilities. The first capability is to work as a six-axis force/torque sensor; additionally, the sensor can be used as a tactile sensor providing a spatially distributed information exploited to estimate the geometry of the contact with a stiff external object. An analytical physical model and a complete experimental characterization of the sensor are presented.
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paper_title: Development of a high-speed multifingered hand system and its application to catching

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In this paper we introduce a newly developed high-speed multi-fingered robotic hand. The hand has 8-joints and 3-fingers. A newly developed small harmonic drive gear and a high-power mini actuator are fitted in each finger link, and a strain gauge sensor is in each joint. The weight of the hand module is only 0.8 kg, but high-speed motion and high-power grasping are possible. The hand can close its joints at 180 deg per 0.1 s, and the fingertips have an output force of about 28 N. The hand system is controlled by a massively parallel vision system. Experimental results are shown in which a falling object was caught by the high-speed hand.
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paper_title: The HIT/DLR dexterous hand: work in progress

paper_content:

This paper presents the current work progress of HIT/DLR Dexterous Hand. Based on the technology of DLR Hand II, HIT and DLR are jointly developing a smaller and easier manufactured robot hand. The prototype of one finger has been successfully built. The finger has three DOF and four joints, the last two joints are mechanically coupled by a rigid linkage. All the actuators are commercial brushless DC motors with integrated analog Hall sensors. DSP based control system is implemented in PCI bus architecture and the serial communication between the hand and DSP needs only 6 lines(4 lines power supply and 2 lines communication interface). The fingertip force can reach 10N.
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paper_title: Dexterous anthropomorphic robot hand with distributed tactile sensor: Gifu hand II

paper_content:

Presents an anthropomorphic robot hand called Gifu hand II that is a revised version of the Gifu hand I. The Gifu hand II has five fingers in which all joints are driven by servomotors built in the fingers and the palm. The thumb has 4 joints with 4 degrees of freedom (DOF), the other fingers have 4 joints with 3 DOF respectively, and two axes of joints near the palm cross orthogonally at one point like the human finger. It can be equipped with a 6 axes force sensor at each fingertip and a developed distributed tactile sensor with 624 detecting points on its surface. The design concepts and the specifications of the Gifu hand II, the basic characteristics of the tactile sensor, and the pressure distributions at object grasping are shown. These show that the Gifu hand II has a high potential to perform dexterous object manipulation like a human hand.
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paper_title: A highly-underactuated robotic hand with force and joint angle sensors

paper_content:

This paper describes a novel underactuated robotic hand design. The hand is highly underactuated as it contains three fingers with three joints each controlled by a single motor. One of the fingers (“thumb”) can also be rotated about the base of the hand, yielding a total of two controllable degrees-of-freedom. A key component of the design is the addition of position and tactile sensors which provide precise angle feedback and binary force feedback. Our mechanical design can be analyzed theoretically to predict contact forces as well as hand position given a particular object shape
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paper_title: Optical sensor for angular position measurements embedded in robotic finger joints

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Abstract This paper presents the modeling and the design of an innovative angular position sensor able to be easily integrated into miniaturized robotic joints (a joint is mm large with a diameter of mm). The sensor working principle is based on the modulation of the light radiant power flux that goes from an InfraRed light emitting diode (IR LED) to a photodiode (PD) through a thickness-varying canal integrated into the joint itself. The LED and the PD are fixed on one of the links that compose the robotic joint, while the canal is integrated into the other link. A model for the interaction between the optoelectronic components is presented, validated, and used to design a robotic joint with the embedded angular sensor. The robotic joint has been characterized and use to implement a complete robotic finger with four embedded angular sensors. The tendon-driven robotic finger has been calibrated and experimentally tested.
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paper_title: Force sensor based on discrete optoelectronic components and compliant frames

paper_content:

Abstract In this paper, a novel force sensor based on commercial discrete optoelectronic components mounted on a compliant frame is described. The compliant frame has been designed through an optimization procedure to achieve a desired relation between the applied force and the angular displacement of the optical axes of the optoelectronic components. The narrow-angle characteristics of Light Emitting Diode (LED) and PhotoDetector (PD) couples have been exploited for the generation of a signal proportional to very limited deformation of the compliant frame caused by the external traction force. This sensor is suitable for applications in the field of tendon driven robots, and in particular the use of this sensor for the measurement of the actuator side tendon force in a robotic hand is reported. The design procedure of the sensor is presented together with the sensor prototype, the experimental verification of the calibration curve and of the frame deformation and the testing in a force feedback control system. The main advantages of this sensor are the simplified conditioning electronics, the very high noise-to-signal ratio and the immunity to electromagnetic fields.
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paper_title: A compliant, underactuated hand for robust manipulation

paper_content:

This paper introduces the i-HY Hand, an underactuated hand driven by 5 actuators that is capable of performing a wide range of grasping and in-hand manipulation tasks. This hand was designed to address the need for a durable, inexpensive, moderately dexterous hand suitable for use on mobile robots. The primary focus of this paper will be on the novel minimalistic design of i-HY, which was developed by choosing a set of target tasks around which the design of the hand was optimized. Particular emphasis is placed on the development of underactuated fingers that are capable of both firm power grasps and low- stiffness fingertip grasps using only the passive mechanics of the finger mechanism. Experimental results demonstrate successful grasping of a wide range of target objects, the stability of fingertip grasping, as well as the ability to adjust the force exerted on grasped objects using the passive finger mechanics.
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paper_title: Fingertip force and position control using force sensor and tactile sensor for Universal Robot Hand II

paper_content:

Various humanoid robots and multi-fingered robot hands are used in research and development. As these robot hands grasp and manipulate an object, the control phase is divided into an “approach phase” and a “manipulation phase.” In the approach phase, a position control method is necessary to control the posture of the robot hand. In the manipulation phase, a force control method is necessary to control the fingertip force of the robot hand. However, it is difficult to control both the force and position of these hands at the same time. In this paper, we propose a grasping force control method based on position control for manipulation. In this proposed method, the finger position is controlled in the direction of the force vector. With this control method, any external force is cancelled and the initial force is kept constant, or the setting force is applied to an object.
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paper_title: DLR's multisensory articulated hand. II. The parallel torque/position control system

paper_content:

Gives a brief description of feedback control systems engaged in DLR's recently developed multisensory 4-finger robot hand. The work is concentrated on constructing the dynamic model and the control strategy for one joint of the fingers. One goal is to make the hand follow a dataglove for fine manipulation tasks. Our proposed strategy for this task is parallel torque/position control; sliding mode control is realized for the robust trajectory tracking in free space; while impedance control is provided for compliance control in the constrained environment; and an easily-designed parallel observer is used for the switch between these two control modes during the transition from or to contact motion. Some experimental results show the effectiveness of proposed strategy for the pure position control, torque control, and the transition control.
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paper_title: DLR's multisensory articulated hand. I. Hard- and software architecture

paper_content:

The main features of DLR's dextrous robot hand as a modular component of a complete robotics system are outlined in this paper. The application of robotics systems in unstructured servicing environments requires dextrous manipulation abilities and facilities to perform complex remote operations in a very flexible way. Therefore we have developed a multisensory articulated four finger hand, where all actuators are integrated in the hand's palm or the fingers directly. It is an integrated part of a complex light-weight manipulation system aiming at the development of robonauts for space. After a brief description of the hand and it's sensorial equipment the hard- and software architecture is outlined with particular emphasis on flexibility and performance issues. The hand is typically controlled through a data glove for telemanipulation and skill-transfer purposes. Autonomous grasping and manipulation capabilities are currently under development.
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paper_title: Design of a fully modular and backdrivable dexterous hand

paper_content:

This paper presents the mechatronic design of a new anthropomorphic hand. It has been developed in the context of a multidisciplinary project which aims at understanding how humans perform the manipulation of objects in order to replicate grasping and in-hand movements with an artificial hand. This has required the development of a new hand with a high level of both anthropomorphism and dexterity. The hand must exactly replicate the kinematics of the human hand, adding up to 24 degrees of mobility and 20 degrees of freedom, which is a design challenge if a high level of dexterity must be guaranteed. Three key concepts have guided the mechanical design: modularity, backdrivability and mechanical simplicity. A modular approach simplifies the complex hand assembly and permits us to concentrate our efforts on one basic unit which will be replicated throughout the hand. Mechanical simplicity and backdrivability ensure a good natural mechanical behavior, essential for stable control of contact forces. Likewise, a better controllability will enhance the dexterity of the hand. A thorough mechanical design assures backdrivability through the whole mechanism, including actuators and transmission of movement to the joints. Experimental results confirm the validity of the design approach and will open new lines of research into robotic hands.
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paper_title: Development of a low cost anthropomorphic robot hand with high capability

paper_content:

This paper presents a development of an anthropomorphic robot hand, ‘KITECH Hand’ that has 4 full-actuated fingers. Most robot hands have small size simultaneously many joints as compared with robot manipulators. Components of actuator, gear, and sensors used for building robots are not small and are expensive, and those make it difficult to build a small sized robot hand. Differently from conventional development of robot hands, KITECH hand adopts a RC servo module that is cheap, easily obtainable, and easy to handle. The RC servo module that have been already used for several small sized humanoid can be new solution of building small sized robot hand with many joints. The feasibility of KITECH hand in object manipulation is shown through various experimental results. It is verified that the modified RC servo module is one of effective solutions in the development of a robot hand.
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paper_title: Anthropomorphic Robot Hand : Gifu Hand III

paper_content:

This paper presents an anthropomorphic robot hand called Gifu Hand III, which is a modified version of Gifu Hand II. The Gifu Hand is aimed to be used as a platform of robot hands for robotics research. The Gifu Hand III is improved on the points of backlash of transmission, opposability of the thumb, and mobility space of fingertips. The opposability of the thumb is evaluated by a cubature of opposable space. An explicit kinematical relation between the fourth joint and the third one is shown, where the fourth joint is engaged with the third joint by a planar four-bars linkage mechanism. The distributed tactile sensor, which has grid pattern electrodes and uses conductive ink, is mounted on the hand surface. The sensor presents 235 points expansion relatively to that of the Gifu Hand II. To reduce insensitive area, the electrodes width and pitch are expanded and narrowed, respectively. In consequence, the insensitive area is reduced to 49.1%. Experiments of grasping several objects are shown. With these improvements and experiments, the Gifu hand III has a higher potential to perform dexterous object manipulations like the human hand.
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paper_title: THE BARRETTHAND GRASPER - PROGRAMMABLY FLEXIBLE PART HANDLING AND ASSEMBLY

paper_content:

This paper details the design and operation of the BarrettHand BH8-250, an intelligent, highly flexible eight-axis gripper that reconfigures itself in real t ime to conform securely to a wide variety of part shapes without tool-change interruptions. The grasper brings enormous value to factory automation because it: reduces the required number and size of robotic work cells (which average US$90,000 each - not including the high cost of footprint) while boosting factory throughput; consolidates the hodgepodge proliferat ion of customized gripper-jaw shapes onto a common programmab le p latform; and enables incremental process imp rovement and accommodates frequent new-product introductions, capabilit ies deployed instantly via software across international networks of factories.
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paper_title: Development of the NAIST-Hand with Vision-based Tactile Fingertip Sensor

paper_content:

This paper introduces a multifingered robotic hand eNAIST-Handf and a grip force control by slip margin feedback. The developed prototype finger of the NAIST-hand has a new mechanism by which all 3 motors can be placed inside the palm without using wire-driven mechanisms. A method of grip force control is proposed using an incipient slip estimation. A new tactile sensor is designed to active the proposed control method by the NAIST-Hand. This sensor consists of a transparent semispherical gel, an embedded small camera, and a force sensor in order to implement the direct slip margin estimation. The structure and the principle of sensing are described.
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paper_title: Development of tactile sensor for detecting contact force and slip

paper_content:

In this paper, a fingertip tactile sensor is presented which can detect contact normal force as well as incipient slip. The sensor, based on polyvinylidene fluoride (PVDF), and pressure variable resistor ink, is physically flexible enough to be deformed into any three-dimensional geometry. In order to detect incipient slip, a PVDF strip is arranged along the direction normal to the surface of the finger of the robot hand. Also, a thin flexible sensor to sense the static force as well as the contact location, is fabricated into an arrayed type using pressure variable resistor ink. In addition, a tactile sensing system is developed with miniaturized electronic hardware such as charge amplifier, signal processing unit etc., and it feasibility is validated experimentally.
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paper_title: Design of a Compliant and Force Sensing Hand for a Humanoid Robot

paper_content:

Abstract : Robot manipulation tasks in unknown and unstructured environments can often be better addressed with hands that are capable of force-sensing and passive compliance. We describe the design of a compact four degree-of-freedom (DOF) hand that exhibits these properties. This hand is being developed for a new humanoid robot platform. Our hand contains four modular Force Sensing Compliant (FSC) actuators acting on three fingers. One actuator controls the spread between two fingers. Three actuators independently control the top knuckle of each finger. The lower knuckles of the finger are passively coupled to the top knuckle. We place a pair of torsion springs between the motor housing and the hand chassis. By measuring the deflection of these springs, we can determine the acting force of the actuator. The springs also provide compliance in the finger and protect the motor gearbox from high impact shocks. Our novel actuators, combined with embedded control electrics, allow for a compact and dexterous hand design that is well suited to humanoid manipulation research.
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paper_title: A tactile sensor sheet using pressure conductive rubber with electrical-wires stitched method

paper_content:

A new type of tactile sensor using pressure-conductive rubber with stitched electrical wires is presented. The sensor is thin and flexible and can cover three-dimensional objects. Since the sensor adopts a single-layer composite structure, the sensor is durable with respect to external force. In order to verify the effectiveness of this tactile sensor, we performed an experiment in which a four-fingered robot hand equipped with tactile sensors grasped sphere and column. The sensor structure, electrical circuit, and characteristics are described. The sensor control system and experimental results are also described.
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paper_title: Reconstructing the Shape of a Deformable Membrane from Image Data

paper_content:

In this paper, we study the problem of determining a mathematical description of the surface defined by the shape of a membrane based on an image of it and present an algorithm for reconstructing the surface when the membrane is deformed by unknown external elements. The given data are the projection on an image plane of markings on the surface of the membrane, the undeformed configuration of the membrane, and a model for the membrane mechanics. The method of re construction is based on the principle that the shape assumed by the membrane will minimize the elastic energy stored in the membrane subject to the constraints implied by the measurements. Energy minimization leads to a set of nonlinear partial differential equations. An approximate solution is found using linearization. The initial motivation, and our first application of these ideas, comes from tactile sensing. Experimental results affirm that this approach can be very effective in this context.
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paper_title: Sensing the texture of surfaces by anthropomorphic soft fingertips with multi-modal sensors

paper_content:

This paper describes the development of a human-like multi-modal soft finger and its ability to sense the texture of objects. This fingertip has two silicon rubber layers of different hardness; strain gauges and PVDF films are randomly distributed as tactile sensors. Owing to the dynamics of the silicon between sensors, the fingertip is supposed to have several sensor modalities. Preliminary experiments show that the fingertip can detect the difference between the textures of objects (paper and wood).
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paper_title: Sensing characteristics of an optical three-axis tactile sensor mounted on a multi-fingered robotic hand

paper_content:

To develop a new three-axis tactile sensor for mounting on multi-fingered robotic hands, in this work we optimize sensing elements on the basis of our previous works concerning optical three-axis tactile sensors with a flat sensing surface. The present tactile sensor is based on the principle of an optical waveguide-type tactile sensor, which is composed of an acrylic hemispherical dome, a light source, an array of rubber sensing elements, and a CCD camera. The sensing element of the present tactile sensor comprises one columnar feeler and eight conical feelers. The contact areas of the conical feelers, which maintain contact with the acrylic dome, detect the three-axis force applied to the tip of the sensing element. Normal and shearing forces are then calculated from integration and centroid displacement of the gray-scale value derived from the conical feeler's contacts. To evaluate the present tactile sensor, we have conducted a series of experiments using a y-z stage, a rotational stage and a force gauge, and have found that although the relationship between integrated gray-scale value and normal force depends on the latitude on the hemispherical surface, it is easy to modify the sensitivity according to the latitude, and that the centroid displacement of the gray-scale value is proportional to the shearing force. Finally, to verify the present tactile sensor, we performed a series of scanning tests using a robotic manipulator equipped with the present tactile sensor to have the manipulator scan surfaces of fine abrasive papers. Results show that the obtained shearing force increased with an increase in the particle diameter of aluminium dioxide contained in the abrasive paper, and decreased with an increase in the scanning velocity of the manipulator over the abrasive paper. Because these results are consistent with tribology, we conclude that the present tactile sensor has sufficient dynamic sensing capability to detect normal and shearing forces.
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paper_title: Electroactive polymeric sensors in hand prostheses: bending response of an ionic polymer metal composite.

paper_content:

In stark contrast to the inspiring functionality of the natural hand, limitations of current upper limb prostheses stemming from marginal feedback control, challenges of mechanical design, and lack of sensory capacity, are well-established. This paper provides a critical review of current sensory systems and the potential of a selection of electroactive polymers for sensory applications in hand prostheses. Candidate electroactive polymers are reviewed in terms of their relevant advantages and disadvantages, together with their current implementation in related applications. Empirical analysis of one of the most novel electroactive polymers, ionic polymer metal composites (IPMC), was conducted to demonstrate its potential for prosthetic applications. With linear responses within the operating range typical of hand prostheses, bending angles, and bending rates were accurately measured with 4.4+/-2.5 and 4.8+/-3.5% error, respectively, using the IPMC sensors. With these comparable error rates to traditional resistive bend sensors and a wide range of sensitivities and responses, electroactive polymers offer a promising alternative to more traditional sensory approaches. Their potential role in prosthetics is further heightened by their flexible and formable structure, and their ability to act as both sensors and actuators.
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paper_title: Tactile sensing in intelligent robotic manipulation – a review

paper_content:

Purpose - When designing hardware and algorithms for robotic manipulation and grasping, sensory information is typically needed to control the grasping process. This paper presents an overview of t ...
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paper_title: Development of the NAIST-Hand with Vision-based Tactile Fingertip Sensor

paper_content:

This paper introduces a multifingered robotic hand eNAIST-Handf and a grip force control by slip margin feedback. The developed prototype finger of the NAIST-hand has a new mechanism by which all 3 motors can be placed inside the palm without using wire-driven mechanisms. A method of grip force control is proposed using an incipient slip estimation. A new tactile sensor is designed to active the proposed control method by the NAIST-Hand. This sensor consists of a transparent semispherical gel, an embedded small camera, and a force sensor in order to implement the direct slip margin estimation. The structure and the principle of sensing are described.
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paper_title: Direct neural sensory feedback and control of a prosthetic arm

paper_content:

Evidence indicates that user acceptance of modern artificial limbs by amputees would be significantly enhanced by a system that provides appropriate, graded, distally referred sensations of touch and joint movement, and that the functionality of limb prostheses would be improved by a more natural control mechanism. We have recently demonstrated that it is possible to implant electrodes within individual fascicles of peripheral nerve stumps in amputees, that stimulation through these electrodes can produce graded, discrete sensations of touch or movement referred to the amputee's phantom hand, and that recordings of motor neuron activity associated with attempted movements of the phantom limb through these electrodes can be used as graded control signals. We report here that this approach allows amputees to both judge and set grip force and joint position in an artificial arm, in the absence of visual input, thus providing a substrate for better integration of the artificial limb into the amputee's body image. We believe this to be the first demonstration of direct neural feedback from and direct neural control of an artificial arm in amputees.
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paper_title: Development of tactile sensor for detecting contact force and slip

paper_content:

In this paper, a fingertip tactile sensor is presented which can detect contact normal force as well as incipient slip. The sensor, based on polyvinylidene fluoride (PVDF), and pressure variable resistor ink, is physically flexible enough to be deformed into any three-dimensional geometry. In order to detect incipient slip, a PVDF strip is arranged along the direction normal to the surface of the finger of the robot hand. Also, a thin flexible sensor to sense the static force as well as the contact location, is fabricated into an arrayed type using pressure variable resistor ink. In addition, a tactile sensing system is developed with miniaturized electronic hardware such as charge amplifier, signal processing unit etc., and it feasibility is validated experimentally.
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paper_title: A tactile sensor sheet using pressure conductive rubber with electrical-wires stitched method

paper_content:

A new type of tactile sensor using pressure-conductive rubber with stitched electrical wires is presented. The sensor is thin and flexible and can cover three-dimensional objects. Since the sensor adopts a single-layer composite structure, the sensor is durable with respect to external force. In order to verify the effectiveness of this tactile sensor, we performed an experiment in which a four-fingered robot hand equipped with tactile sensors grasped sphere and column. The sensor structure, electrical circuit, and characteristics are described. The sensor control system and experimental results are also described.
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paper_title: Tactile Sensing for Robotic Manipulation

paper_content:

In several fields of robotics, tactile and force sensors represent a basic tool for achieving an enhanced interaction with the environment. As a matter of fact, areas such as advanced manipulation, telemanipulation, haptic devices, legged robots and so on are intrinsically based on an advanced sensorial equipment and on proper techniques for the exploitation of their information. These types of sensors give information such as the presence of a contact, its size and shape, the exchanged forces/torques. More advanced sensors can also provide additional information, such as mechanical properties of the bodies in contact (e.g. friction coefficient, roughness, . . . ) or the slippage. In this chapter, an overview on tactile and force sensors and their specific use in robotic manipulation is presented. In particular, after an illustration of the state of the art and of the main recent technological developments, results concerning the detection and control of the relative motion (slippage) of two bodies in contact are discussed. This problem may be of relevance, e.g. in advanced manipulation by robotic systems in which, depending on the task to be executed, it might be desirable either to avoid or to exploit the slippage of the manipulated object. Similar problems can be found with legged robots, or more in general in any case where a robotic device has to interact with its environment in a controlled manner. These and other applications have justified an increasing research effort in this field in the last years, generating several interesting prototypes and techniques for data analysis.
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paper_title: Anatomically correct testbed hand control: Muscle and joint control strategies

paper_content:

Human hands are capable of many dexterous grasping and manipulation tasks. To understand human levels of dexterity and to achieve it with robotic hands, we constructed an anatomically correct testbed (ACT) hand which allows for the investigation of the biomechanical features and neural control strategies of the human hand. This paper focuses on developing control strategies for the index finger motion of the ACT Hand. A direct muscle position control and a force-optimized joint control are implemented as building blocks and tools for comparisons with future biological control approaches. We show how Gaussian process regression techniques can be used to determine the relationships between the muscle and joint motions in both controllers. Our experiments demonstrate that the direct muscle position controller allows for accurate and fast position tracking, while the force-optimized joint controller allows for exploitation of actuation redundancy in the finger critical for this redundant system. Furthermore, a comparison between Gaussian processes and least squares regression method shows that Gaussian processes provide better parameter estimation and tracking performance. This first control investigation on the ACT hand opens doors to implement biological strategies observed in humans and achieve the ultimate human-level dexterity.
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paper_title: Design and Evaluation of a Low-Cost Force Feedback System for Myoelectric Prosthetic Hands

paper_content:

Myoelectrically powered prosthetic hands lack sensory feedback relating to the force exerted by the artificial hand on a grasped object. The degree of control is imprecise, and often much more force than necessary is applied. The aim of this study was to develop and evaluate a force feedback system considering design constraints, providing the user with closed-loop control. Different methods and design criteria for providing myoelectric prosthetic hands with force feedback were analyzed, with stimulation by vibration being preferred. A new feedback system was designed, consisting of a miniature vibration motor, a piezoresistive force sensor, and control electronics. Grasping forces with and without feedback were recorded and compared from five habitual myoelectric hand users when grasping a hand dynamometer with different weights attached to it. All five patients rapidly improved their ability to regulate the grasping force without the help of vision when feedback was applied. An average force reduction of 37% was found when vibration was applied indirectly to the hand, and a decrease of 54% was found when feedback was applied directly to the skin of the residual limb. Constraints for a prosthetic force feedback system such as low power consumption, compactness, and being imperceptible to others are included in the design. General acceptance of vibration as a feedback signal was good, especially when applied indirectly. The results indicate that the new system is of potential value for myoelectric prosthetic hand users. More precise control is possible, and redundant grasping force can be diminished with a feedback system. (J Prosthet Orthot. 2006;18:1‐1.) KEY INDEXING TERMS: closed-loop control, force feedback, prosthetic hand, sensor, vibration
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paper_title: Underactuated five-finger prosthetic hand inspired by grasping force distribution of humans

paper_content:

Simple grippers with one or two degrees of freedom are commercially available prosthetic hands; these pinch type devices cannot grasp small cylinders and spheres because of their small degree of freedom. This paper presents the design and prototyping of underactuated five-finger prosthetic hand for grasping various objects in daily life. Underactuated mechanism enables the prosthetic hand to move fifteen compliant joints only by one ultrasonic motor. The innovative design of this prosthetic hand is the underactuated mechanism optimized to distribute grasping force like those of humans who can grasp various objects robustly. Thanks to human like force distribution, the prototype of prosthetic hand could grasp various objects in daily life and heavy objects with the maximum ejection force of 50 N that is greater than other underactuated prosthetic hands.
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paper_title: Design of a cybernetic hand for perception and action

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Strong motivation for developing new prosthetic hand devices is provided by the fact that low functionality and controllability—in addition to poor cosmetic appearance—are the most important reasons why amputees do not regularly use their prosthetic hands. This paper presents the design of the CyberHand, a cybernetic anthropomorphic hand intended to provide amputees with functional hand replacement. Its design was bio-inspired in terms of its modular architecture, its physical appearance, kinematics, sensorization, and actuation, and its multilevel control system. Its underactuated mechanisms allow separate control of each digit as well as thumb–finger opposition and, accordingly, can generate a multitude of grasps. Its sensory system was designed to provide proprioceptive information as well as to emulate fundamental functional properties of human tactile mechanoreceptors of specific importance for grasp-and-hold tasks. The CyberHand control system presumes just a few efferent and afferent channels and was divided in two main layers: a high-level control that interprets the user’s intention (grasp selection and required force level) and can provide pertinent sensory feedback and a low-level control responsible for actuating specific grasps and applying the desired total force by taking advantage of the intelligent mechanics. The grasps made available by the high-level controller include those fundamental for activities of daily living: cylindrical, spherical, tridigital (tripod), and lateral grasps. The modular and flexible design of the CyberHand makes it suitable for incremental development of sensorization, interfacing, and control strategies and, as such, it will be a useful tool not only for clinical research but also for addressing neuroscientific hypotheses regarding sensorimotor control.
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paper_title: Upper limb amputees can be induced to experience a rubber hand as their own

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We describe how upper limb amputees can be made to experience a rubber hand as part of their own body. This was accomplished by applying synchronous touches to the stump, which was out of view, and to the index finger of a rubber hand, placed in full view (26 cm medial to the stump). This elicited an illusion of sensing touch on the artificial hand, rather than on the stump and a feeling of ownership of the rubber hand developed. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioural data in the form of misreaching in a pointing task when asked to localize the position of the touch, and physiological evidence obtained by skin conductance responses when threatening the hand prosthesis. Our findings outline a simple method for transferring tactile sensations from the stump to a prosthetic limb by tricking the brain, thereby making an important contribution to the field of neuroprosthetics where a major goal is to develop artificial limbs that feel like a real parts of the body.
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paper_title: Referral of sensation to an advanced humanoid robotic hand prosthesis

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Hand prostheses that are currently available on the market are used by amputees to only a limited extent, partly because of lack of sensory feedback from the artificial hand. We report a pilot study that showed how amputees can experience a robot-like advanced hand prosthesis as part of their own body. We induced a perceptual illusion by which touch applied to the stump of the arm was experienced from the artificial hand. This illusion was elicited by applying synchronous tactile stimulation to the hidden amputation stump and the robotic hand prosthesis in full view. In five people who had had upper limb amputations this stimulation caused referral touch sensation from the stump to the artificial hand, and the prosthesis was experienced more like a real hand. We also showed that this illusion can work when the amputee controls the movements of the artificial hand by recordings of the arm muscle activity with electromyograms. These observations indicate that the previously described “rubber hand illusion” ...
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paper_title: Design and control of a shape memory alloy based dexterous robot hand

paper_content:

Modern externally powered upper-body prostheses are conventionally actuated by electric servomotors. Although these motors achieve reasonable kinematic performance, they are voluminous and heavy. Deterring factors such as these lead to a substantial proportion of upper extremity amputees avoiding the use of their prostheses. Therefore, it is apparent that there exists a need for functional prosthetic devices that are compact and lightweight. The realization of such a device requires an alternative actuation technology, and biological inspiration suggests that tendon based systems are advantageous. Shape memory alloys are a type of smart material that exhibit an actuation mechanism resembling the biological equivalent. As such, shape memory alloy enabled devices promise to be of major importance in the future of dexterous robotics, and of prosthetics in particular. This paper investigates the design, instrumentation, and control issues surrounding the practical application of shape memory alloys as artificial muscles in a three-fingered robot hand.
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paper_title: Multi-fingered robotic hand employing strings transmission named “Twist Drive” — Video contribution

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A goal of our research is to produce a light-weight, low-cost five fingered robotic hand that has similar degrees of freedom as a human hand. The joints in the fingers of the developed robotic hand are powered by a newly proposed strings transmission named “Twist Drive”. The transmission converts torque into a pulling force by using a pair of strings that twist on each other. The basic characteristics of the transmission are given in the paper. A robotic hand prototype with 18 joints of which 14 are independently powered by Twist Drives was produced. The size of the hand is equal to the size of an adult human's hand and its weight including the power circuits is approximately 800 grams. The mechanical and the control systems of the hand are presented in the paper.
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paper_title: Development of intelligent robot hand using proximity, contact and slip sensing

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To achieve the skillful task like the human, many researchers have been working on robot hand. An interaction with vision and tactile information are indispensable for realization of skillful tasks. In the existing research, the method using a camera to get the vision information is often found. But, in the boundary area of a non-contact phase and a contact phase, there are problem that lack of sensor information because the influence of occlusion comes up to surface. We devise to introduce the proximity sensor in this area. And we call the robot hand which is equipped with proximity, tactile and slip sensor “intelligent robot hand”. In this research, we show the constitution example of the intelligent robot hand and propose the method to realize Pick&Place as concrete task.
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paper_title: A multi-sensor system applied to control an intelligent robotic hand for underwater environment

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We present a multi-sensors system adopted in an intelligent robotic hand that works in underwater environment. Four kinds of different sensors, force sensor, image sensor, ultrasonic sensor and hall sensor, are adopted in this system. Among them, information gained by force sensors formed a closed loop together with the control variables in the system, thus, the accuracy and stability of the whole system is improved remarkably. An upper computer is applied to merge the information gathered by these sensors and send commands to actuators. In order that the system can act as required stably, we applied some protecting methods in the software. With the help of this system, we can control the intelligent robotic hand in real time all by human or let it work automatically.
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paper_title: Grasping Force Control of Multi-fingered Robot Hand based on Slip Detection Using Tactile Sensor

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To achieve a human like grasping by the multi-fingered robot hand, grasping force should be controlled without information of the grasping object such as the weight and the friction coefficient. In this study, we propose a method for detecting the slip of grasping object by force output of the Center of Pressure (CoP) tactile sensor. CoP sensor can measure center position of distributed load and total load which is applied on the surface of the sensor within 1 [ms] . This sensor is arranged on finger of the robot hand, and the effectiveness as slip detecting sensor is confirmed by experiment of slip detection on grasping. Finally, we propose a method for controlling grasping force resist the tangential force added to the grasping object by feedback control system of the CoP sensor force output.
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paper_title: Development of a high-speed multifingered hand system and its application to catching

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In this paper we introduce a newly developed high-speed multi-fingered robotic hand. The hand has 8-joints and 3-fingers. A newly developed small harmonic drive gear and a high-power mini actuator are fitted in each finger link, and a strain gauge sensor is in each joint. The weight of the hand module is only 0.8 kg, but high-speed motion and high-power grasping are possible. The hand can close its joints at 180 deg per 0.1 s, and the fingertips have an output force of about 28 N. The hand system is controlled by a massively parallel vision system. Experimental results are shown in which a falling object was caught by the high-speed hand.
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paper_title: The HIT/DLR dexterous hand: work in progress

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This paper presents the current work progress of HIT/DLR Dexterous Hand. Based on the technology of DLR Hand II, HIT and DLR are jointly developing a smaller and easier manufactured robot hand. The prototype of one finger has been successfully built. The finger has three DOF and four joints, the last two joints are mechanically coupled by a rigid linkage. All the actuators are commercial brushless DC motors with integrated analog Hall sensors. DSP based control system is implemented in PCI bus architecture and the serial communication between the hand and DSP needs only 6 lines(4 lines power supply and 2 lines communication interface). The fingertip force can reach 10N.
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paper_title: One-handed knotting of a flexible rope with a high-speed multifingered hand having tactile sensors

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This paper proposes a new strategy for making knots with a high-speed multifingered robot hand having tactile sensors. The strategy is divided into three skills: loop production, rope permutation, and rope pulling. Through these three skills, a knot can be made with a single multifingered robot hand. The dynamics of the rope permutation are analyzed in order to improve the success rate, and an effective tactile feedback control method is proposed based on the analysis. Finally, experimental results are shown.
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paper_title: Multisensory five-finger dexterous hand: The DLR/HIT Hand II

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This paper presents a new developed multisensory five-fingered dexterous robot hand: the DLR/HIT Hand II. The hand has an independent palm and five identical modular fingers, each finger has three DOFs and four joints. All the actuators and electronics are integrated in the finger body and the palm. By using powerful super flat brushless DC motors, tiny harmonic drivers and BGA form DSPs and FPGAs, the whole fingerpsilas size is about one third smaller than the former finger in the DLR/HIT Hand I. By using the steel coupling mechanism, the phalanx distalpsilas transmission ratio is exact 1:1 in the whole movement range. At the same time, the multisensory dexterous hand integrates position, force/torque and temperature sensors. The hierarchical hardware structure of the hand consists of the finger DSPs, the finger FPGAs, the palm FPGA and the PCI based DSP/FPGA board. The hand can communicate with external with PPSeCo, CAN and Internet. Instead of extra cover, the packing mechanism of the hand is implemented directly in the finger body and palm to make the hand smaller and more human like. The whole weight of the hand is about 1.5Kg and the fingertip force can reach 10N.
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paper_title: Modularly designed lightweight anthropomorphic robot hand

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In this paper, the modular design of artificial hands is presented. The modular concept shall be introduced based on the example of the artificial anthropomorphic hand prototype, which is part of the project for the development of a human assistive robot. Particular attention shall be dedicated to details of modular construction and servicing of the hand prototype. Prototype components, functional activities, technical characteristics, and the control system of the hand shall be introduced as well. Additionally, two hand prototypes were attached to a humanoid service robot and first experience gained from their operation will be presented in conclusion.
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paper_title: Bio-inspired sensorization of a biomechatronic robot hand for the grasp-and-lift task

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It has been concluded from numerous neurophysiological studies that humans rely on detecting discrete mechanical events that occur when grasping, lifting and replacing an object, i.e., during a prototypical manipulation task. Such events represent transitions between phases of the evolving manipulation task such as object contact, lift-off, etc., and appear to provide critical information required for the sequential control of the task as well as for corrections and parameterization of the task. We have sensorized a biomechatronic anthropomorphic hand with the goal to detect such mechanical transients. The developed sensors were designed to specifically provide the information about task-relevant discrete events rather than to mimic their biological counterparts. To accomplish this we have developed (1) a contact sensor that can be applied to the surface of the robotic fingers and that show a sensitivity to indentation and a spatial resolution comparable to that of the human glabrous skin, and (2) a sensitive low-noise three-axial force sensor that was embedded in the robotic fingertips and showed a frequency response covering the range observed in biological tactile sensors. We describe the design and fabrication of these sensors, their sensory properties and show representative recordings from the sensors during grasp-and-lift tasks. We show how the combined use of the two sensors is able to provide information about crucial mechanical events during such tasks. We discuss the importance of the sensorized hand as a test bed for low-level grasp controllers and for the development of functional sensory feedback from prosthetic devices.
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paper_title: Design of anthropomorphic dexterous hand with passive joints and sensitive soft skins

paper_content:

Installation of passive elements on the skin (whole-part covered soft skin) and inside joints of the robotic hand becomes a key-technology to remarkably enhance the stability of object handling and manipulation and adaptability to external forces. Based on this idea, in this paper a sophisticated mechanism design of TWENDY-ONE hands with mechanical springs in DIP and MP joints and whole-part covered soft skins is presented. In addition, we present a design method of tactile sensors for highly dexterous robotic hand, whish are necessary for recognition of volume and softness of objects grasped as well as improvement of handling and manipulation more stably. Evaluation experiments focusing on kitchen supports using TWENDY-ONE hands indicate that this new robot has high dexterity due to the hand and will be extremely useful to enhance the quality of life for the elderly in the near future where human and robot co-exist.
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paper_title: The modular multisensory DLR-HIT-Hand

paper_content:

Abstract The paper presents hardware and software architecture of the new developed compact multisensory DLR-HIT hand. The hand has four identical fingers and an extra degree of freedom for palm. In each finger there is a Field Programmable Gate Array (FPGA) for data collection, brushless DC motors control and communication with palm’s FPGA by Point-to-Point Serial Communication (PPSeCo). The kernel of the hardware system is a PCI-based high speed floating-point Digital Signal Processor (DSP) for data processing, and FPGA for high speed (up to 25 Mbps) real-time serial communication with the palm’s FPGA. In order to achieve high modularity and reliability of the hand, a fully mechatronic integration and analog signals in situ digitalization philosophy are implemented to minimize the dimension, number of the cables (five cables including power supply) and protect data communication from outside disturbances. Furthermore, according to the hardware structure of the hand, a hierarchical software structure has been established to perform all data processing and the control of the hand. It provides basic API functions and skills to access all hardware resources for data acquisition, computation and tele-operation. With the nice design of the hand’s envelop, the hand looks more like humanoid.
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paper_title: Dynamic Pen Spinning Using a High-speed Multifingered Hand with High-speed Tactile Sensor

paper_content:

We propose a tactile feedback system in real time using a high-speed multifingered robot hand and high-speed tactile sensor. The system is respectively capable of high-speed finger motion up to 180 deg per 0.1 s and high-speed tactile feedback with a sampling rate higher than 1 kHz. In this paper, we describe dynamic pen spinning as an example of a skillful manipulation task using a high-speed multifingered hand equipped with tactile sensors. The paper describes the tactile feedback control strategies and experimental results.
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paper_title: Biomimetic Tactile Sensor Array

paper_content:

The performance of robotic and prosthetic hands in unstructured environments is severely limited by their having little or no tactile information compared to the rich tactile feedback of the human ...
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paper_title: High-Resolution Thin-Film Device to Sense Texture by Touch

paper_content:

Touch (or tactile) sensors are gaining renewed interest as the level of sophistication in the application of minimum invasive surgery and humanoid robots increases. The spatial resolution of current large-area (greater than 1 cm 2 ) tactile sensor lags by more than an order of magnitude compared with the human finger. By using metal and semiconducting nanoparticles, a ∼100-nm-thick, large-area thin-film device is self-assembled such that the change in current density through the film and the electroluminescent light intensity are linearly proportional to the local stress. A stress image is obtained by pressing a copper grid and a United States 1-cent coin on the device and focusing the resulting electroluminescent light directly on the charge-coupled device. Both the lateral and height resolution of texture are comparable to the human finger at similar stress levels of ∼10 kilopascals.
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paper_title: Tactile sensing for an anthropomorphic robotic hand: Hardware and signal processing

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In this paper, a tactile sensing system for an anthropomorphic robot hand is presented. The tactile sensing system is designed as a construction kit making it very versatile. The sensor data preprocessing is embedded into the hand's hardware structure and is fully integrated. The sensor system is able to gather tactile pressure profiles and to measure vibrations in the sensor's cover. Additionally to the introduction of the hardware, the signal processing and the classification of the acquired sensor data will be explained in detail. These algorithms make the tactile sensing system capable to detect contact points, to classify contact patterns and to detect slip conditions during object manipulation and grasping.
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paper_title: Grip Control Using Biomimetic Tactile Sensing Systems

paper_content:

We present a proof-of-concept for controlling the grasp of an anthropomorphic mechatronic prosthetic hand by using a biomimetic tactile sensor, Bayesian inference, and simple algorithms for estimation and control. The sensor takes advantage of its compliant mechanics to provide a triaxial force sensing end-effector for grasp control. By calculating normal and shear forces at the fingertip, the prosthetic hand is able to maintain perturbed objects within the force cone to prevent slip. A Kalman filter is used as a noise-robust method to calculate tangential forces. Biologically inspired algorithms and heuristics are presented that can be implemented online to support rapid, reflexive adjustments of grip.
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paper_title: A sensor for dynamic tactile information with applications in human-robot interaction and object exploration

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We present a novel tactile sensor, which is applied for dextrous grasping with a simple robot gripper. The hardware novelty consists of an array of capacitive sensors, which couple to the object by means of little brushes of fibers. These sensor elements are very sensitive (with a threshold of about 5 mN) but robust enough not to be damaged during grasping. They yield two types of dynamical tactile information corresponding roughly to two types of tactile sensor in the human skin. The complete sensor consists of a foil-based static force sensor, which yields the total force and the center of the two-dimensional force distribution and is surrounded by an array of the dynamical sensor elements. One such sensor has been mounted on each of the two gripper jaws of our humanoid robot and equipped with the necessary read-out electronics and a CAN bus interface. We describe applications to guiding a robot arm on a desired trajectory with negligible force, reflective grip improvement, and tactile exploration of objects to create a shape representation and find stable grips, which are applied autonomously on the basis of visual recognition.
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paper_title: A tactile sensor for the fingertips of the humanoid robot iCub

paper_content:

In order to successfully perform object manipulation, humanoid robots must be equipped with tactile sensors. However, the limited space that is available in robotic fingers imposes severe design constraints. In [1] we presented a small prototype fingertip which incorporates a capacitive pressure system. This paper shows an improved version, which has been integrated on the hand of the humanoid robot iCub. The fingertip is 14.5 mm long and 13 mm wide. The capacitive pressure sensor system has 12 sensitive zones and includes the electronics to send the 12 measurements over a serial bus with only 4 wires. Each synthetic fingertip is shaped approximately like a human fingertip. Furthermore, an integral part of the capacitive sensor is soft silicone foam, and therefore the fingertip is compliant. We describe the structure of the fingertip, their integration on the humanoid robot iCub and present test results to show the characteristics of the sensor.
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paper_title: A robust micro-vibration sensor for biomimetic fingertips

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Controlling grip force in a prosthetic or robotic hand requires detailed sensory feedback information about microslips between the artificial fingertips and the object. In the biological hand this is accomplished with neural transducers capable of measuring micro-vibrations in the skin due to sliding friction. For prosthetic tactile sensors, emulating these biological transducers is a difficult challenge due to the fragility associated with highly sensitive devices. Incorporating a pressure sensor into a fluid-filled fingertip provides a novel solution to this problem by effectively creating a device similar to a hydrophone, capable of recording vibrations from lateral movements. The fluid conducts these acoustic signals well and with little attenuation, permitting the pressure sensing elements to be located in a protected region inside the core of the sensor and removing them from harmpsilas way. Preliminary studies demonstrate that high frequency vibrations (50-400 Hz) can be readily detected when such a fingertip slides across a ridged surface.
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paper_title: Piezoelectric Vibration-Type Tactile Sensor Using Elasticity and Viscosity Change of Structure

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We propose a new tactile sensor utilizing piezoelectric vibration. This tactile sensor has a high sensitivity, wide measurement range, pressure resistance, flexibility, and self-sensing function. This tactile sensor comprises two piezoelectric materials. One is used for the vibration of the sensor element and the other is used for the measurement of the change in mechanical impedance induced by an external force. We achieved the wide measurement range by implementing two ideas. One was to apply the external force to the sensor element through an elastic body and the other was to use two or more modes of vibration. Moreover, for the elastic body, it is preferable to use a material whose elasticity and viscosity are easily changed by an external force, such as a gel. In this study, first, this tactile sensor was analyzed, and then its characteristics were derived. The analytical results qualitatively corresponded to the experimental results. Next, a prototype tactile sensor was fabricated and evaluated. The evaluation results showed that this tactile sensor can measure a pressure of 2.5 Pa or less and a pressure of 10 kPa or more and its pressure resistance is 1 MPa or more.
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paper_title: Signal processing and fabrication of a biomimetic tactile sensor array with thermal, force and microvibration modalities

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We have developed a finger-shaped sensor array that provides simultaneous information about the contact forces, microvibrations and thermal fluxes induced by contact with external objects. In this paper, we describe a microprocessor-based signal conditioning and digitizing system for these sensing modalities and its embodiment on a flex-circuit that facilitates efficient assembly of the entire system via injection molding. Thermal energy from the embedded electronics is used to heat the finger above ambient temperature, similar to the biological finger. This enables the material properties of contacted objects to be inferred from thermal transients measured by a thermistor in the sensor array. Combining sensor modalities provides synergistic benefits. For example, the contact forces for exploratory movements can be calibrated so that thermal and microvibration data can be interpreted more definitively.
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paper_title: An embedded artificial skin for humanoid robots

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A novel artificial skin for covering the whole body of a humanoid robot is presented. It provides pressure measurements and shape information about the contact surfaces between the robot and the environment. The system is based on a mesh of sensors interconnected in order to form a networked structure. Each sensor has 12 capacitive taxels, has a triangular shape and is supported by a flexible substrate in order to conform to smooth curved surfaces. Three communications ports placed along the sides of each sensor sides allow communications with adjacent sensors. The tactile measurements are sent to embed microcontroller boards using serial bus communication links. The system can adaptively reduce its spatial resolution, improving the response time. This feature is very useful for detecting the first contact very rapidly, at a lower spatial resolution, and then increase the spatial resolution in the region of contact for accurate reconstruction of the contact pressure distribution.
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paper_title: Electric Field Servoing for robotic manipulation

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This paper presents two experiments with electric field servoing for robotic manipulation. In the first, a robot hand pre-shapes to the geometry and pose of objects to be grasped, by servoing each finger according to the values on EF sensors built in to each finger. In the second, a 7 degree of freedom arm aligns itself in 2 dimensions with a target object using electric field measurements as the error signal. This system also allows the end effector to dynamically track the target object as it is moved.
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paper_title: An Electric Field Pretouch system for grasping and co-manipulation

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Pretouch sensing is longer range than contact, but shorter range than vision. The hypothesis motivating this work is that closed loop feedback based on short range but non-contact measurements can improve the reliability of manipulation. This paper presents a grasping system that is guided at short range by Electric Field (EF) Pretouch. We describe two sets of experiments. The first set of experiments involves human-to-robot and robot-to-human handoff, including the use of EF Pretouch to detect whether or not a human is also touching an object that the robot is holding, which we call the “co-manipulation state.” In the second set of experiments, the robot picks up standalone objects. We describe a number of techniques that servo the arm and fingers in order to both collect relevant geometrical information, and to actually perform the manipulation task.
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paper_title: A robust, low-cost and low-noise artificial skin for human-friendly robots

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As robots and humans move towards sharing the same environment, the need for safety in robotic systems is of growing importance. Towards this goal of human-friendly robotics, a robust, low-cost, low-noise capacitive force sensing array is presented with application as a whole body artificial skin covering. This highly scalable design provides excellent noise immunity, low-hysteresis, and has the potential to be made flexible and formable. Noise immunity is accomplished through the use of shielding and local sensor processing. A small and low-cost multivibrator circuit is replicated locally at each taxel, minimizing stray capacitance and noise coupling. Each circuit has a digital pulse train output, which allows robust signal transmission in noisy electrical environments. Wire count is minimized through serial or row-column addressing schemes, and the use of an open-drain output on each taxel allows hundreds of sensors to require only a single output wire. With a small set of interface wires, large arrays can be scanned hundreds of times per second and dynamic response remains flat over a broad frequency range. Sensor performance is evaluated on a bench-top version of a 4×4 taxel array in quasi-static and dynamic cases.
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paper_title: Unknown Object Grasping Strategy Imitating Human Grasping Reflex for Anthropomorphic Robot Hand

paper_content:

This paper presents a grasping strategy for unknown objects that imitating human grasping reflex for the anthropomorphic robot hands. A 10 months baby may bend his/her thumb and 4 fingers trying to grasp an object when it is in contact with the palm. After grasping it, if the object is plucked from the baby's hand, the baby holds the object more strongly. In addition, the hand approaches the object by only touching the palm lightly. The reaction of the hand is called a grasping reflex. In the proposed grasping strategy, each joint of the thumb and the fingers is controlled independently using the contact force affecting its adjacent fingertip side link to imitate the grasping reflex. By setting a suitable contact force, both fingertip grasping and enveloped grasping with uniform grasping force are executable. Experimental results of grasping three dimensional unknown objects by using an anthropomorphic robot hand called Gifu Hand III are shown.
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paper_title: Electric field imaging pretouch for robotic graspers

paper_content:

This paper proposes the use of electric field sensors to implement "pretouch" for robotic grasping. Weakly electric fish use this perceptual channel, but it has not received much attention in robotics. This paper describes a series of manipulators each of which incorporates electric field sensors in a different fashion. In each case, the paper presents techniques for using the sensors, and experimental data collected. First, a simple dynamic-object avoidance technique is presented. Next, a 1-D alignment task for grasping is described. Then linear and rotary electrode scanning techniques are presented. It is shown that these techniques can distinguish a small object at close range from a large object farther away, a capability that may be important for grasping.
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paper_title: Repetitive grasping with anthropomorphic skin-covered hand enables robust haptic recognition

paper_content:

Skin is an essential component of artificial hands. It enables the use of object affordance for recognition and control, but due to its intrinsic locality and low density of current tactile sensors, stable and proper manual contacts with the objects are indispensable. Recently, design of hand structure have shown to be effective for adaptive grasping. However, such adaptive design are only introduced to the fingers in existing works of haptics and their role in recognition remains unclear. This paper introduces the design of the Bionic Hand; an anthropomorphic hand with adaptive design introduced to the whole hand and fully covered with sensitive skin. The experiment shows that anthropomorphic design of hand structure enables robust haptic recognition by convergence of object contact conditions into stable representative states through repetitive grasping. The structure of the human hand is found to solve the issue of narrowing down the sensor space for haptic object recognition by morphological computation.
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paper_title: Dual-Mode Capacitive Proximity Sensor for Robot Application: Implementation of Tactile and Proximity Sensing Capability on a Single Polymer Platform Using Shared Electrodes

paper_content:

In this paper, we report a flexible dual-mode capacitive sensor for robot applications which has two sensing capabilities in a single platform; tactile and proximity sensing capability. The sensor consists of a mechanical structure based on PDMS (Polydimethylsiloxane) and a mesh of multiple copper electrode strips. The mesh is composed of 16 top and 16 bottom copper strips crossed each other to form a 16 times 16 capacitor array. The proposed sensor is able to switch its function from tactile sensing to proximity sensing or vice versa by reconfiguring the connection of electrodes. The tactile sensing capability has been demonstrated already and reported in our previous paper (Lee et al.,, 2006); therefore, in this paper, we will demonstrate the feasibility of the proximity sensing capability and the dual-mode operation of the proposed sensor in detail. The capacitance change caused by an approaching object has been estimated through simulation of multiple two-dimensional models as an initial study. The measured data have shown similar trends with the simulation results. We tested various materials from conducting metals to a human hand for proximity measurement. The fabricated sensor could detect a human hand at a distance up to 17 cm away from the sensor. We also have successfully demonstrated the feasibility of dual-mode operation of the proposed sensor in real-time exploiting a custom designed PCB, a data acquisition pad, and Labview software.
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paper_title: Robust sensor-based grasp primitive for a three-finger robot hand

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This paper addresses the problem of robot grasping in conditions of uncertainty. We propose a grasp controller that deals robustly with this uncertainty using feedback from different contact-based sensors. This controller assumes a description of grasp consisting of a primitive that only determines the initial configuration of the hand and the control law to be used. We exhaustively validate the controller by carrying out a large number of tests with different degrees of inaccuracy in the pose of the target objects and by comparing it with results of a naive grasp controller.
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paper_title: Adaptive grasping by multi fingered hand with tactile sensor based on robust force and position control

paper_content:

In this paper we propose a new robust force and position control method for property-unknown objects grasping. The proposed control method is capable of selecting the force control or position control, and smooth and quick switching according to the amount of the external force. The proposed method was applied to adaptive grasping by three-fingered hand which has 12 DOF, and the experimental results revealed that the smooth collision process and the stable grasping is realized even if the precise surface position, the mass and the stiffness are unknown. In addition a new algorithm determines the grasp force according to the "slip" measured with the tactile sensor and the viscoelastic media on the fingertip. This algorithm works at starting and stationary state, so the friction and mass unknown object grasping is realized by the effectual force.
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paper_title: Anthropomorphic Robot Hand : Gifu Hand III

paper_content:

This paper presents an anthropomorphic robot hand called Gifu Hand III, which is a modified version of Gifu Hand II. The Gifu Hand is aimed to be used as a platform of robot hands for robotics research. The Gifu Hand III is improved on the points of backlash of transmission, opposability of the thumb, and mobility space of fingertips. The opposability of the thumb is evaluated by a cubature of opposable space. An explicit kinematical relation between the fourth joint and the third one is shown, where the fourth joint is engaged with the third joint by a planar four-bars linkage mechanism. The distributed tactile sensor, which has grid pattern electrodes and uses conductive ink, is mounted on the hand surface. The sensor presents 235 points expansion relatively to that of the Gifu Hand II. To reduce insensitive area, the electrodes width and pitch are expanded and narrowed, respectively. In consequence, the insensitive area is reduced to 49.1%. Experiments of grasping several objects are shown. With these improvements and experiments, the Gifu hand III has a higher potential to perform dexterous object manipulations like the human hand.
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paper_title: Tactile sensing for dexterous in-hand manipulation in robotics-A review

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Abstract As the field of robotics is expanding from the fixed environment of a production line to complex human environments, robots are required to perform increasingly human-like manipulation tasks, moving the state-of-the-art in robotics from grasping to advanced in-hand manipulation tasks such as regrasping, rotation and translation. To achieve advanced in-hand manipulation tasks, robotic hands are required to be equipped with distributed tactile sensing that can continuously provide information about the magnitude and direction of forces at all contact points between them and the objects they are interacting with. This paper reviews the state-of-the-art in force and tactile sensing technologies that can be suitable within the specific context of dexterous in-hand manipulation. In previous reviews of tactile sensing for robotic manipulation, the specific functional and technical requirements of dexterous in-hand manipulation, as compared to grasping, are in general not taken into account. This paper provides a review of models describing human hand activity and movements, and a set of functional and technical specifications for in-hand manipulation is defined. The paper proceeds to review the current state-of-the-art tactile sensor solutions that fulfil or can fulfil these criteria. An analytical comparison of the reviewed solutions is presented, and the advantages and disadvantages of different sensing technologies are compared.
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paper_title: Skin-inspired electronic devices

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Electronic devices that mimic the properties of skin have potential important applications in advanced robotics, prosthetics, and health monitoring technologies. Methods for measuring tactile and temperature signals have progressed rapidly due to innovations in materials and processing methods. Imparting skin-like stretchability to electronic devices can be accomplished by patterning traditional electronic materials or developing new materials that are intrinsically stretchable. The incorporation of sensing methods with transistors facilitates large-area sensor arrays. While sensor arrays have surpassed the properties of human skin in terms of sensitivity, time response, and device density, many opportunities remain for future development.
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paper_title: Development of a Flexible 3-D Tactile Sensor System for Anthropomorphic Artificial Hand

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In this paper, we report a novel flexible tactile sensor array for an anthropomorphic artificial hand with the capability of measuring both normal and shear force distributions using quantum tunneling composite as a base material. There are four fan-shaped electrodes in a cell that decompose the contact force into normal and shear components. The sensor has been realized in a 2ntn 6 array of unit sensors, and each unit sensor responds to normal and shear stresses in all three axes. By applying separated drops of conductive polymer instead of a full layer, cross-talk between the sensor cells is decreased. Furthermore, the voltage mirror method is used in this circuit to avoid crosstalk effect, which is based on a programmable system-on-chip. The measurement of a single sensor shows that the full-scale range of detectable forces are about 20, 8, and 8 N for the x-, y-, and z-directions, respectively. The sensitivities of a cell measured with a current setup are 0.47, 0.45, and 0.16 mV/mN for the x-, y-, and y-directions, respectively. The sensor showed a high repeatability, low hysteresis, and minimum tactile crosstalk. The proposed flexible three-axial tactile sensor array can be applied in a curved or compliant surface that requires slip detection and flexibility, such as a robotic finger.
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paper_title: Bayesian Exploration for Intelligent Identification of Textures

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In order to endow robots with humanlike abilities to characterize and identify objects, they must be provided with tactile sensors and intelligent algorithms to select, control and interpret data from useful exploratory movements. Humans make informed decisions on the sequence of exploratory movements that would yield the most information for the task, depending on what the object may be and prior knowledge of what to expect from possible exploratory movements. This study is focused on texture discrimination, a subset of a much larger group of exploratory movements and percepts that humans use to discriminate, characterize, and identify objects. Using a testbed equipped with a biologically inspired tactile sensor (the BioTac®) we produced sliding movements similar to those that humans make when exploring textures. Measurement of tactile vibrations and reaction forces when exploring textures were used to extract measures of textural properties inspired from psychophysical literature (traction, roughness, and fineness). Different combinations of normal force and velocity were identified to be useful for each of these three properties. A total of 117 textures were explored with these three movements to create a database of “prior experience” to use for identifying these same textures in future encounters. When exploring a texture, the discrimination algorithm adaptively selects the optimal movement to make and property to measure based on previous experience to differentiate the texture from a set of plausible candidates, a process we call Bayesian exploration. Performance of 99.6% in correctly discriminating pairs of similar textures was found to exceed human capabilities. Absolute classification from the entire set of 117 textures generally required a small number of well-chosen exploratory movements (median=5) and yielded a 95.4% success rate. The method of “Bayesian exploration” developed and tested in this paper may generalize well to other cognitive problems.
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paper_title: Highly sensitive sensor for detection of initial slip and its application in a multi-fingered robot hand

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Tactile sensors for slip detection are essential for implementing human-like gripping in a robot hand. In previous studies, we proposed flexible, thin and lightweight slip detection sensors utilizing the characteristics of pressure-sensitive conductive rubber. This was achieved by using the high-frequency vibration component generated in the process of slipping of the gripped object in order to distinguish between slipping of the object and changes in the normal force. In this paper, we design a slip detection sensor for a multi-fingered robot hand and examine the influence of noise caused by the operation of such a hand. Finally, we describe an experiment focusing on the adjustment of the gripping force of a multi-fingered robot hand equipped with the developed sensors
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paper_title: A soft, amorphous skin that can sense and localize textures

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We present a soft, amorphous skin that can sense and localize textures. The skin consists of a series of sensing and computing elements that are networked with their local neighbors and mimic the function of the Pacinian corpuscle in human skin. Each sensor node samples a vibration signal at 1 KHz, transforms the signal into the frequency domain, and classifies up to 15 textures using logistic regression. By measuring the power spectrum of the signal and comparing it with its local neighbors, computing elements can then collaboratively estimate the location of the stimulus. The resulting low-bandwidth information, consisting of the texture probability distribution and its location are then routed to a sink anywhere in the skin in a multi-hop fashion. We describe the design, manufacturing, classification, localization and networking algorithms and experimentally validate the proposed approach. In particular, we demonstrate texture classification with 71% accuracy and centimeter accuracy in localization over an area of approximately three square feet using ten networked sensor nodes.
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paper_title: Grasping Force Control of Multi-fingered Robot Hand based on Slip Detection Using Tactile Sensor

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To achieve a human like grasping by the multi-fingered robot hand, grasping force should be controlled without information of the grasping object such as the weight and the friction coefficient. In this study, we propose a method for detecting the slip of grasping object by force output of the Center of Pressure (CoP) tactile sensor. CoP sensor can measure center position of distributed load and total load which is applied on the surface of the sensor within 1 [ms] . This sensor is arranged on finger of the robot hand, and the effectiveness as slip detecting sensor is confirmed by experiment of slip detection on grasping. Finally, we propose a method for controlling grasping force resist the tangential force added to the grasping object by feedback control system of the CoP sensor force output.
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paper_title: Tactile identification of objects using Bayesian exploration

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In order to endow robots with human-like tactile sensory abilities, they must be provided with tactile sensors and intelligent algorithms to select and control useful exploratory movements and interpret data from all available sensors. Current robotic systems do not possess such sensors or algorithms. In this study we integrate multimodal tactile sensing (force, vibration and temperature) from the BioTac® with a Shadow Dexterous Hand and program the robot to make exploratory movements similar to those humans make when identifying objects by their compliance, texture, and thermal properties. Signal processing strategies were developed to provide measures of these perceptual properties. When identifying an object, exploratory movements are intelligently selected using a process we have previously developed called Bayesian exploration [1], whereby exploratory movements that provide the most disambiguation between likely candidates of objects are automatically selected. The exploration algorithm was augmented with reinforcement learning whereby its internal representations of objects evolved according to its cumulative experience with them. This allowed the algorithm to compensate for drift in the performance of the anthropomorphic robot hand and the ambient conditions of testing, improving accuracy while reducing the number of exploratory movements required to identify an object. The robot correctly identified 10 different objects on 99 out of 100 presentations.
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paper_title: An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film.

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Pressure sensing is an important function of electronic skin devices. The development of pressure sensors that can mimic and surpass the subtle pressure sensing properties of natural skin requires the rational design of materials and devices. Here we present an ultra-sensitive resistive pressure sensor based on an elastic, microstructured conducting polymer thin film. The elastic microstructured film is prepared from a polypyrrole hydrogel using a multiphase reaction that produced a hollow-sphere microstructure that endows polypyrrole with structure-derived elasticity and a low effective elastic modulus. The contact area between the microstructured thin film and the electrodes increases with the application of pressure, enabling the device to detect low pressures with ultra-high sensitivity. Our pressure sensor based on an elastic microstructured thin film enables the detection of pressures of less than 1Pa and exhibits a short response time, good reproducibility, excellent cycling stability and temperature-stable sensing.
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paper_title: Online in-hand object localization

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Robotic hands are a key component of humanoids. Initially more fragile and larger than their human counterparts, the technology has evolved and the latest generation is close to the human hand in size and robustness. However, it is still disappointing to see how little robotic hands are able to do once the grasp is acquired due to the difficulty to obtain a reliable pose of the object within the palm. This paper presents a novel method based on a particle filter used to estimate online the object pose. It is shown that the method is robust, accurate and handles many realistic scenario without hand crafted rules. It combines an efficient collision checker with a few very simple ideas, that require only a basic knowledge of the geometry of the objects. It is shown, by experiments and simulations, that the algorithm is able to deal with inaccurate finger position measurements and can integrate tactile measurements. The method greatly enhances the performance of common manipulation operations, such as a pick and place tasks, and boosts the sensing capabilities of the robot.
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paper_title: Finger-shaped thermal sensor using thermo-sensitive paint and camera for telexistence

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A thermal change on a fingertip is essential for haptic perception. We have proposed a vision-based thermal sensor using thermo-sensitive paint and a CCD camera for telexistence. The thermo-sensitive paint is employed to measure thermal information on the basis of its color, which changes according to its temperature. The proposed sensor can simulate the physical interaction between a human fingertip and an object in order to measure surface thermal information correctly. Furthermore, because the proposed sensor can be easily integrated with our vision-based force sensor, a comprehensive measurement device for measuring haptic information can be realized. In this study, we constructed a prototype of the proposed thermal sensor and experimentally confirmed that this sensor could measure surface thermal information.
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paper_title: Bioinspired Sinusoidal Finger Joint Synergies for a Dexterous Robotic Hand to Screw and Unscrew Objects With Different Diameters

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This paper addresses the complex task of unscrewing and screwing objects with a dexterous anthropomorphic robotic hand in two cases: with the first finger and thumb and also with the little finger and thumb. To develop an anthropomorphic solution, human finger synergies from nine test subjects were recorded while unscrewing and screwing a threaded cap. Human results showed that the periodic motions exhibited by the finger joints shared a common frequency for each subject, but differed in amplitude and phase. From the gathered data, a set of sinusoidal trajectories were developed to approximate this motion for application to a robotic hand. Because the joint trajectories exhibited the same frequency, a family of sinusoids that share a common time vector can be used in the path planning of the robotic hand to unscrew and screw objects. Additionally, the human unscrewing data are highly similar to the mirror image of the screwing data. This chiastic trait enables screwing to be performed by decreasing the time vector; increasing the time vector produces unscrewing. These factors significantly reduce the computational cost and complexity of the task. Cartesian and joint space error analyses show that the developed sinusoidal trajectories closely mimic the motion profiles seen in the human experiments. Furthermore, this bioinspired sinusoidal solution is extended to objects with wide variations in diameters by relating joint angle offsets of the robotic hand to object diameter size through the forward kinematics equations. The sinusoidal trajectories are all implemented within a PID sliding mode controller for a dexterous artificial hand to ensure overall system stability. Using the bioinspired sinusoidal joint angle trajectories, the robotic hand successfully unscrewed and screwed four different objects in all trials conducted with each object diameter size.
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paper_title: Adaptive Sliding Mode Control for Prosthetic Hands to Simultaneously Prevent Slip and Minimize Deformation of Grasped Objects

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Adaptive sliding mode and integral sliding mode grasped object slip prevention controllers are implemented for a prosthetic hand and compared to a proportional derivative shear force feedback slip prevention controller as well as a sliding mode controller without slip prevention capabilities. Slip of grasped objects is detected by band-pass filtering the shear force derivative to amplify high frequency vibrations that occur as the grasped object slides relative to the fingers. The integral sliding mode slip prevention controller provides a robust design framework for slip prevention while addressing the issue of reducing the amount of deformation that the grasped object experiences to prevent slip. Averaged results from bench top experiments show that the integral sliding mode slip prevention controller produces the least amount of deformation to the grasped object while simultaneously preventing the object from being dropped.
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paper_title: Majority Voting: Material Classification by Tactile Sensing Using Surface Texture

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In this paper, we present an application of machine learning to distinguish between different materials based on their surface texture. Such a system can be used for the estimation of surface friction during manipulation tasks; quality assurance in the textile, cosmetics, and harvesting industries; and other applications requiring tactile sensing. Several machine learning algorithms, such as naive Bayes, decision trees, and naive Bayes trees, have been trained to distinguish textures sensed by a biologically inspired artificial finger. The finger has randomly distributed strain gauges and polyvinylidene fluoride (PVDF) films embedded in silicone. Different textures induce different intensities of vibrations in the silicone. Consequently, textures can be distinguished by the presence of different frequencies in the signal. The data from the finger are preprocessed, and the Fourier coefficients of the sensor outputs are used to train classifiers. We show that the classifiers generalize well for unseen datasets with performance exceeding previously reported algorithms. Our classifiers can distinguish between different materials, such as carpet, flooring vinyls, tiles, sponge, wood, and polyvinyl-chloride (PVC) woven mesh with an accuracy of on unseen test data.
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paper_title: Design of a flexible tactile sensor for classification of rigid and deformable objects

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For both humans and robots, tactile sensing is important for interaction with the environment: it is the core sensing used for exploration and manipulation of objects. In this paper, we present a novel tactile-array sensor based on flexible piezoresistive rubber. We describe the design of the sensor and data acquisition system. We evaluate the sensitivity and robustness of the sensor, and show that it is consistent over time with little relaxation. Furthermore, the sensor has the benefit of being flexible, having a high resolution, it is easy to mount, and simple to manufacture. We demonstrate the use of the sensor in an active object-classification system. A robotic gripper with two sensors mounted on its fingers performs a palpation procedure on a set of objects. By squeezing an object, the robot actively explores the material properties, and the system acquires tactile information corresponding to the resulting pressure. Based on a k nearest neighbor classifier and using dynamic time warping to calculate the distance between different time series, the system is able to successfully classify objects. Our sensor demonstrates similar classification performance to the Weiss Robotics tactile sensor, while having additional benefits.
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paper_title: Using robotic exploratory procedures to learn the meaning of haptic adjectives

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Delivering on the promise of real-world robotics will require robots that can communicate with humans through natural language by learning new words and concepts through their daily experiences. Our research strives to create a robot that can learn the meaning of haptic adjectives by directly touching objects. By equipping the PR2 humanoid robot with state-of-the-art biomimetic tactile sensors that measure temperature, pressure, and fingertip deformations, we created a platform uniquely capable of feeling the physical properties of everyday objects. The robot used five exploratory procedures to touch 51 objects that were annotated by human participants with 34 binary adjective labels. We present both static and dynamic learning methods to discover the meaning of these adjectives from the labeled objects, achieving average F1 scores of 0.57 and 0.79 on a set of eight previously unfelt items.
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paper_title: Semi-anthropomorphic 3D printed multigrasp hand for industrial and service robots

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This paper presents the preliminary prototype design and implementation of the Nazarbayev University (NU) Hand, a new semi-anthropomorphic multigrasp robotic hand. The hand is designed to be an end effector for industrial and service robots. The main objective is to develop a low-cost, low-weight and easily manufacturable robotic hand with a sensor module allowing acquisition of data for autonomous intelligent object manipulation. 3D printing technologies were extensively used in the implementation of the hand. Specifically, the structure of the hand is printed using a 3D printer as a complete assembly voiding the need of using fasteners and bearings for the assembly of the hand and decreasing the total weight. The hand also incorporates a sensor module containing a LIDAR, digital camera and non-contact infrared temperature sensor for intelligent automation. As an alternative to teach pendants for the industrial manipulators, a teaching glove was developed, which acts as the primary human machine interface between the user and the NU Hand. The paper presents an extensive performance characterization of the robotic hand including finger forces, weight, audible noise level during operation and sensor data acquisition.
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paper_title: A stretchable carbon nanotube strain sensor for human-motion detection

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Thin films of single-wall carbon nanotube have been used to create stretchable devices that can be incorporated into clothes and used to detect human motions.
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paper_title: A Soft Strain Sensor Based on Ionic and Metal Liquids

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A novel soft strain sensor capable of withstanding strains of up to 100% is described. The sensor is made of a hyperelastic silicone elastomer that contains embedded microchannels filled with conductive liquids. This is an effort of improving the previously reported soft sensors that uses a single liquid conductor. The proposed sensor employs a hybrid approach involving two liquid conductors: an ionic solution and an eutectic gallium-indium alloy. This hybrid method reduces the sensitivity to noise that may be caused by variations in electrical resistance of the wire interface and undesired stress applied to signal routing areas. The bridge between these two liquids is made conductive by doping the elastomer locally with nickel nanoparticles. The design, fabrication, and characterization of the sensor are presented.
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paper_title: Using Near-Field Stereo Vision for Robotic Grasping in Cluttered Environments

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Robotic grasping in unstructured environments requires the ability to adjust and recover when a pre-planned grasp faces imminent failure. Even for a single object, modeling uncertainties due to occluded surfaces, sensor noise and calibration errors can cause grasp failure; cluttered environments exacerbate the problem. In this work, we propose a simple but robust approach to both pre-touch grasp adjustment and grasp planning for unknown objects in clutter, using a small-baseline stereo camera attached to the gripper of the robot. By employing a 3D sensor from the perspective of the gripper we gain information about the object and nearby obstacles immediately prior to grasping that is not available during head-sensor-based grasp planning. We use a feature-based cost function on local 3D data to evaluate the feasibility of a proposed grasp. In cases where only minor adjustments are needed, our algorithm uses gradient descent on a cost function based on local features to find optimal grasps near the original grasp. In cases where no suitable grasp is found, the robot can search for a significantly different grasp pose rather than blindly attempting a doomed grasp. We present experimental results to validate our approach by grasping a wide range of unknown objects in cluttered scenes. Our results show that reactive pre-touch adjustment can correct for a fair amount of uncertainty in the measured position and shape of the objects, or the presence of nearby obstacles.
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paper_title: Methods for safe human-robot-interaction using capacitive tactile proximity sensors

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In this paper we base upon capacitive tactile proximity sensor modules developed in a previous work to demonstrate applications for safe human-robot-interaction. Arranged as a matrix, the modules can be used to model events in the near proximity of the robot surface, closing the near field perception gap in robotics. The central application investigated here is object tracking. Several results are shown: the tracking of two human hands as well as the handling of occlusions and the prediction of collision for object trajectories. These results are important for novel pretouch- and touch-based humanrobot interaction strategies and for assessing and implementing safety capabilities with these sensor systems.
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paper_title: Using depth and appearance features for informed robot grasping of highly wrinkled clothes

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Detecting grasping points is a key problem in cloth manipulation. Most current approaches follow a multiple re-grasp strategy for this purpose, in which clothes are sequentially grasped from different points until one of them yields to a desired configuration. In this paper, by contrast, we circumvent the need for multiple re-graspings by building a robust detector that identifies the grasping points, generally in one single step, even when clothes are highly wrinkled.
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paper_title: Seashell effect pretouch sensing for robotic grasping

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This paper introduces seashell effect pretouch sensing, and demonstrates application of this new sensing modality to robot grasp control, and also to robot grasp planning.
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paper_title: Pre-shaping for various objects by the robot hand equipped with resistor network structure proximity sensors

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In this paper, we demonstrate a preliminary motion before grasping by a robot hand, for adjusting the object-fingertip distance and 2-axis postures simultaneously, using a Resistor Network Structure Proximity sensor (RNSP sensor). Through this motion (called “pre-shaping”) and the grasping of an object, the surface of each fingertip is brought into contact with the object surface so that in the next stage grasping can be undertaken. In the next stage, a force can be applied from the fingertips onto the object surface directly. The pre-shaping enhances the reliability of the feedback control for the after-contact tactile sensors. To realize the pre-shaping, we use fingertips equipped with RNSP sensors, which can detect the distance between the fingertip and the object, to determine the relative position between fingertips and an object. The RNSP sensor has a fast response (<;1 [ms]) and simple connectivity (only 6 wires), and can be mounted easily. Additionally, a characteristics of the RNSP sensor output can be designed by the arrangement of the sensor elements. To perform the pre-shaping by simple sensor feedback control based on the configuration between the fingertip and object, we designed the RNSP sensor so that it had the appropriate characteristics for the pre-shaping.
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paper_title: Fusion of stereo vision, force-torque, and joint sensors for estimation of in-hand object location

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This paper develops a method to fuse stereo vision, force-torque sensor, and joint angle encoder measurements to estimate and track the location of a grasped object within the hand. We pose the problem as a hybrid systems estimation problem, where the continuous states are the object 6D pose, finger contact location, wrist-to-camera transform and the discrete states are the finger contact modes with the object. This paper develops the key measurement equations that govern the fusion process. Experiments with a Barrett Hand, Bumblebee 2 stereo camera, and an ATI omega force-torque sensor validate and demonstrate the method.
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paper_title: Finger-shaped thermal sensor using thermo-sensitive paint and camera for telexistence

paper_content:

A thermal change on a fingertip is essential for haptic perception. We have proposed a vision-based thermal sensor using thermo-sensitive paint and a CCD camera for telexistence. The thermo-sensitive paint is employed to measure thermal information on the basis of its color, which changes according to its temperature. The proposed sensor can simulate the physical interaction between a human fingertip and an object in order to measure surface thermal information correctly. Furthermore, because the proposed sensor can be easily integrated with our vision-based force sensor, a comprehensive measurement device for measuring haptic information can be realized. In this study, we constructed a prototype of the proposed thermal sensor and experimentally confirmed that this sensor could measure surface thermal information.
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Title: Sensors for Robotic Hands: A Survey of State of the Art

Section 1: INTRODUCTION
Description 1: Summarize the evolution, functionality, and importance of the human hand, and outline the origins and development of artificial hands, including their design challenges and multidisciplinary nature.

Section 2: 2000 -2005
Description 2: Provide a comprehensive review of the advancements in artificial hand development from 2000 to 2005, focusing on prosthetic hands, research platforms, developments in tactile and force sensors, and significant projects.

Section 3: 2005 -2010
Description 3: Discuss the progress in artificial hand technologies between 2005 and 2010, highlighting innovations in prosthetic hands, research platforms, actuation and transmission mechanisms affecting sensors, and tactile sensing.

Section 4: 2010 -2015
Description 4: Outline the key trends and developments in artificial hand sensors from 2010 to 2015, emphasizing multimodal sensing, artificial skin, and advancements in tactile sensor technologies.

Section 5: CONCLUSION
Description 5: Summarize the survey findings, project future trends in artificial hand sensor development, and discuss the continuing technical challenges and opportunities in the field.