Application of NiTi in Assistive and Rehabilitation Devices: A Review
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paper_title: Biomimetic actuators in prosthetic and rehabilitation applications.

paper_content:

Where humans and mechanical systems operate in close proximity there is a need to provide drive systems that combine the positive attributes of conventional actuator design with a 'softer' safer interaction capacity. This is achieved by natural muscle, and engineering emulation of this functionality could have a significant benefits in many areas, but particularly the medical domain. This work will study the use of compliance regulated and controlled pairs of antagonistic pneumatic Muscle Actuators (pMAs) in two medical scenarios; i) The construction of dexterous prosthetic hands having a high power and low mass potential, ii) The construction of a power assist device that can be used to augment the strength of those suffering from degenerative muscle wasting diseases.
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paper_title: Mechanical design of a shape memory alloy actuated prosthetic hand

paper_content:

This paper presents the mechanical design for a new five fingered, twenty degree-of-freedom dexterous hand patterned after human anatomy and actuated by Shape Memory Alloy artificial muscles. Two experimental prototypes of a finger, one fabricated by traditional means and another fabricated by rapid prototyping techniques, are described and used to evaluate the design. An important aspect of the Rapid Prototype technique used here is that this multi-articulated hand will be fabricated in one step, without requiring assembly, while maintaining its desired mobility. The use of Shape Memory Alloy actuators combined with the rapid fabrication of the non-assembly type hand, reduce considerably its weight and fabrication time. Therefore, the focus of this paper is the mechanical design of a dexterous hand that combines Rapid Prototype techniques and smart actuators. The type of robotic hand described in this paper can be utilized for applications requiring low weight, compactness, and dexterity such as prosthetic devices, space and planetary exploration.
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paper_title: Fabrication of Non-Assembly Mechanisms and Robotic Systems Using Rapid Prototyping

paper_content:

In this paper, the application of Rapid Prototyping in fabricating non-assembly robotic systems and mechanisms is presented. Using two Rapid Prototyping techniques, Stereolithography and Selective Laser Sintering, prototypes of mechanical mobile joints were fabricated. The designs of these component joints were then used to fabricate the articulated structure of experimental prototypes for two robotic systems: (1) a three-legged parallel manipulator, (2) a four degree-of-freedom finger of a five-fingered robotic hand. These complex multi-articulated, multi-link, multi-loop systems have been fabricated in one step, without requiring assembly while maintaining their desired mobility. The feasibility and usefulness of Rapid Prototyping as a method for the fabrication of these non-assembly type mechanisms and robotic systems is the focus of this work.
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paper_title: Shape memory alloy actuated robot prostheses: initial experiments

paper_content:

Describes the objectives of a project, which are to design artificial limbs that are lightweight, compact and dexterous, that mimic human anatomy and maintain a high lifting capability. The key to satisfying these objectives is the use of shape memory alloy (SMA) artificial muscles as actuators. A general methodology to find the placement of SMA wires to achieve desired ranges of motion is presented. Two experimental prototypes, emulating human skeletal structures that are actuated by SMA artificial muscles are described in detail.
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paper_title: Development and Control of a Multifunctional Prosthetic Hand with Shape Memory Alloy Actuators

paper_content:

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: Design of an anthropomorphic prosthetic hand driven by Shape Memory Alloy actuators

paper_content:

This paper presents the mechanical design of an ultra-lightweight, biomimetically actuated anthropomorphic hand for prosthetic purposes. The proposed design is based on an underactuated configuration of 16 joints and 7 active degrees of freedom. Shape Memory Alloy wires are used as motive elements of a specially designed actuation system installed within the envelope of the hand and forearm; due to their inherent contraction ability when heated, these innovative micro-actuators produce linear motion which is imparted to the fingers via a tendon transmission system. The overall design is completed with the integration of the necessary locking mechanisms for power saving. An experimental prototype of the suggested prosthesis has been fabricated using rapid prototyping techniques and it will be used as an evaluation platform for further research towards the development of a truly multifunctional, silent and cosmetically appealing hand for upper limb amputees.
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paper_title: Design of an innovative prosthetic hand with compact shape memory alloy actuators

paper_content:

Shape memory alloy actuation is one of the emerging technologies that shows up remarkable advantages compared to conventional actuation. In this research work, this technology is exploited in driving an innovative prosthetic hand designed to meet most of the requirements of the upper limb amputees. Compact and totally silent linear actuation units are developed and integrated within a lightweight housing closely replicating the shape and size of the average human hand. In addition, a tendon-driven underactuated mechanism provides the necessary dexterity without compromising the simplicity of the device. The physical implementation of the hand chassis is accomplished using rapid prototyping techniques. Experiments with a single-finger testbed are conducted in order to evaluate speed performance and investigate the feasibility of a resistance feedback control scheme.
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paper_title: Mechanical design of a shape memory alloy actuated prosthetic hand

paper_content:

This paper presents the mechanical design for a new five fingered, twenty degree-of-freedom dexterous hand patterned after human anatomy and actuated by Shape Memory Alloy artificial muscles. Two experimental prototypes of a finger, one fabricated by traditional means and another fabricated by rapid prototyping techniques, are described and used to evaluate the design. An important aspect of the Rapid Prototype technique used here is that this multi-articulated hand will be fabricated in one step, without requiring assembly, while maintaining its desired mobility. The use of Shape Memory Alloy actuators combined with the rapid fabrication of the non-assembly type hand, reduce considerably its weight and fabrication time. Therefore, the focus of this paper is the mechanical design of a dexterous hand that combines Rapid Prototype techniques and smart actuators. The type of robotic hand described in this paper can be utilized for applications requiring low weight, compactness, and dexterity such as prosthetic devices, space and planetary exploration.
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paper_title: Fabrication of Non-Assembly Mechanisms and Robotic Systems Using Rapid Prototyping

paper_content:

In this paper, the application of Rapid Prototyping in fabricating non-assembly robotic systems and mechanisms is presented. Using two Rapid Prototyping techniques, Stereolithography and Selective Laser Sintering, prototypes of mechanical mobile joints were fabricated. The designs of these component joints were then used to fabricate the articulated structure of experimental prototypes for two robotic systems: (1) a three-legged parallel manipulator, (2) a four degree-of-freedom finger of a five-fingered robotic hand. These complex multi-articulated, multi-link, multi-loop systems have been fabricated in one step, without requiring assembly while maintaining their desired mobility. The feasibility and usefulness of Rapid Prototyping as a method for the fabrication of these non-assembly type mechanisms and robotic systems is the focus of this work.
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paper_title: Shape memory alloy actuated robot prostheses: initial experiments

paper_content:

Describes the objectives of a project, which are to design artificial limbs that are lightweight, compact and dexterous, that mimic human anatomy and maintain a high lifting capability. The key to satisfying these objectives is the use of shape memory alloy (SMA) artificial muscles as actuators. A general methodology to find the placement of SMA wires to achieve desired ranges of motion is presented. Two experimental prototypes, emulating human skeletal structures that are actuated by SMA artificial muscles are described in detail.
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paper_title: Experimental Study of a Shape Memory Alloy Actuation System for a Novel Prosthetic Hand

paper_content:

Recently, the development of compact, light-weight and powerful actuation systems has been in the centre of investigation at many scientific institutions and research groups all over the world. These systems can be used in devices of almost every aspect of modern life and based on their inherent technology they come with certain benefits and costs. One of the most demanding applications field in terms of actuator selection and design is the field of upper-extremity prosthetics. Modern commercial advanced hand and arm prostheses are conventionally actuated by electric servomotors. Although these motors achieve reasonable kinematic performance, they have been proven insufficient in meeting amputees’ demands, mainly due to their noisy operation and limited energy density which leads to the use of bulky and heavy driving systems (Herr, 2003). Therefore, an alternative nonconventional actuation technology is requisite in order to overcome these limitations which make a substantial proportion of upper-limb amputees avoiding the use of their prostheses. One of the most promising actuation technologies is based on Shape Memory Alloys (SMA) and phenomena related to change of their atomic structure. SMA are metallic alloys that can exhibit an actuation mechanism resembling the biological muscle they contract producing actuation forces. These muscle-like actuators present high power to weight ratio enabling the development of compact, lightweight prosthetic devices without too much compromising power capabilities and eliminating the forced-tradeoff between dexterity and anthropomorphic size, weight and appearance (Bundhoo, 2009). Additional benefits include an inherent position feedback method (given a near linear relationship between ohmic resistance and contraction), silent, smooth and life-like operation, and the lack of requirement for force or motion transmission devices (Kyberd et al., 2001). During the last two decades SMA have been studied and reviewed as possible actuation technology in prosthetics by many researchers but efficiency and response time are claimed as the most limiting factors (Del Cura et al., 2003). So, in order to render this material appropriate for application in upper-limb prostheses, these impediments must be overcome. Towards this scope, an innovative SMA actuation system for a newly developed prosthetic hand is constructed and studied. The technology applied in this hand offers a series of improvements when compared to current commercial prosthetic devices. Its design 5
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paper_title: Development and Control of a Multifunctional Prosthetic Hand with Shape Memory Alloy Actuators

paper_content:

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.
---
paper_title: Design of an innovative prosthetic hand with compact shape memory alloy actuators

paper_content:

Shape memory alloy actuation is one of the emerging technologies that shows up remarkable advantages compared to conventional actuation. In this research work, this technology is exploited in driving an innovative prosthetic hand designed to meet most of the requirements of the upper limb amputees. Compact and totally silent linear actuation units are developed and integrated within a lightweight housing closely replicating the shape and size of the average human hand. In addition, a tendon-driven underactuated mechanism provides the necessary dexterity without compromising the simplicity of the device. The physical implementation of the hand chassis is accomplished using rapid prototyping techniques. Experiments with a single-finger testbed are conducted in order to evaluate speed performance and investigate the feasibility of a resistance feedback control scheme.
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paper_title: Prosthetic Hand Using Shape Memory Alloy Type Artificial Muscle

paper_content:

A new prosthetic hand with a fixed thumb and four fingers actuated by Shape Memory Alloy (SMA) type artificial muscle has been developed in this paper. Different from typical geared motor, SMA actuator is lightweight and silent, however shows a little short stroke and small attracting force per each unit. In order to achieve enough output force and motion range of each finger, multiple SMA type artificial muscles with special device which facilitates enough length are equipped in the hand. The fundamental properties of the SMA type artificial muscle including output force and electrical response were determined experimentally and considered for the design of hand mechanism. Besides, the structure of each finger and whole system has been designed based on observation of human hand. The electrical hardware to control multiple shape memory alloy type artificial muscles has been also developed. Finally, the usefulness of the prosthetic hand has been investigated through experiments for grasping several types of objects.
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paper_title: Flexible Artificial Muscle Actuator Using Coiled Shape Memory Alloy Wires

paper_content:

Abstract This paper presents a flexible artificial muscle actuator using coiled shape memory alloy (SMA) wires. The actuator mainly consisted of flexible materials and SMA wires and the fabrication was based on molding of silicon rubber. The actuator was also characterized by the motion with the body in flexion. We measured several characteristics to investigate a relationship between the bending angle of its body and the actuation. As the results, we confirmed that it was possible to actuate with the body in flexion.
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paper_title: The use of muscle “creep” as opposed to relaxation in stretching braces: a pseudoelastic device

paper_content:

Traditional orthoses reduce muscle contractures by constraining limbs in increasingly more extended positions in which muscles and tissues relax. This paper proposes a new approach to achieve muscle stretching by applying a quasi-constant force without constraining any particular position. This is possible by exploiting the wide deformation range and peculiar mechanical response of pseudoelastic NiTi, which was utilized to built an elbow brace (EDGES). Per-clinical tests on two hemiplegic patients showed that improvement of resting elbow angle can be achieved in a week’s application and that this type of orthosis is much more easily accepted by patients than traditional ones. Further tests will address the possibility of stabilizing elbow posture through plastic tissue remodeling.
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paper_title: Pseudoelastic alloy devices for spastic elbow relaxation

paper_content:

Pseudoelastic alloys have never been utilised in rehabilitation medicine yet. A compliant dynamic brace (EDGES) promoting spastic elbow relaxation was designed for clinical use and helped investigate the potentialities of pseudolastic NiTi in orthotics. Two post-stroke subjects wore EDGES for 1 week, at least 10h a day. No additional treatment was applied to the examined arm during this period or the following week. A great improvement of the resting position was observed in both patients as early as 3h after starting the treatment. During walking, EDGES did not constrain limb movements and was thus very well accepted by the patients. A slight decrease in elbow flexors spasticity was also observed in all subjects, but this effect disappeared 1 week after discontinuation, as did posture improvements. EDGES appears to be a good alternative to traditional orthoses in terms of acceptability and effectiveness in improving posture, and it could be very useful whenever short-term splinting is planned.
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paper_title: Pseudoelastic Nitinol-Based Device for Relaxation of Spastic Elbow in Stroke Patients

paper_content:

A compliant brace (EDGES) promoting spastic elbow relaxation was designed to investigate the potentialities of pseudoelastic NiTi in orthotics. By exploiting its peculiar characteristics, EDGES could improve elbow posture without constraining movements and thus avoiding any pain to the patient. A commercial Ni50.7-Ti49.3 alloy heat treated at 400 °C 1 h + WQ was selected for this application. A prototype of EDGES was assembled with two thermoplastic shells connected by polycentric hinges. Four 2-mm-diameter NiTi bars were encastred in the upper-arm shell and let slide along tubular fixtures on the forearm. Specially designed bending tests demonstrated suitable moment-angle characteristics. Two post-stroke subjects (aged 62 and 64, mild elbow flexors spasticity) wore EDGES for 1 week, at least 10 h a day. No additional treatment was applied during this period or the following week. A great improvement (20° ± 5°) of the resting position was observed in both patients as early as 3 h after starting the treatment. Acceptability was very good. A slight decrease in spasticity was also observed in both subjects. All the effects disappeared 1 week after discontinuation. EDGES appears to be a good alternative to traditional orthoses in terms of acceptability and effectiveness in improving posture, especially whenever short-term splinting is planned.
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paper_title: Customizable neuro-mechanical model of a hemiplegic elbow interacting with a pseudoelastic dynamic orthosis

paper_content:

This paper presents a clinically-oriented mathematical model of the elbow, capable to simulate treatment scenarios, particularly in the case of orthotic therapy by pseudoelastic stretching braces. The model is divided into two patient-customizable lumped-parameter subsystems to include spinal mono- and poly-synaptic reflexes, joint contracture, muscle co-contraction, dystonia and spasticity on one side; plastic remodeling and therapeutic variables, on the other. An example of simulation is presented mimicking application of the NiTi-based brace EDGES during 1 month, 12h/day on a mock chronic hemiplegic subject. The model can be used to plan brace prescription and foresee patient-specific results.
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paper_title: Wearable Elbow Exoskeleton Actuated with Shape Memory Alloy

paper_content:

This paper presents a wearable rehabilitation exoskeleton for the elbow joint with two degrees of freedom (DOF), flexion-extension and pronation-supination, actuated with Shape Memory Alloy (SMA) based actuators. Due to the actuation system, the proposed exoskeleton presents a light weight, low noise, and is designed in a simple structure. The number of actuators and the preliminary designed was calculated based on a biomechanical simulation with a specific category of patients.
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paper_title: State of the Art Review of Knee–Ankle–Foot Orthoses

paper_content:

Knee–ankle–foot orthoses (KAFOs) are used to assist in ambulation. The purpose of this paper is to review existing KAFO designs which can be grouped into passive KAFOs, stance control (SC) KAFOs, and dynamic KAFOs. The conventional passive KAFOs do not provide any active control for knee motions. SCKAFOs lock the knee joint during the stance phase and allow free rotations during the swing phase. Some SCKAFOs switch between the stance and swing phases using body posture, while others use some kind of a control system to perform this switch. Finally, dynamic KAFOs control the knee joint during both stance and swing phases. Four dynamic systems are identified in the literature that use pneumatics, linear springs, hydraulics, and torsional rods made of superelastic alloys to control the knee joint during the gait cycle. However, only the two systems that use linear springs and torsional rods can reproduce the normal knee stiffness pattern which has two distinct characteristics: a soft stiffness during the swing phase and a hard stiffness during the stance phase. This review indicates that there is a need to conduct research regarding new KAFO designs that duplicate normal knee function during the whole gait cycle.
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paper_title: The gait and energy efficiency of stance control knee–ankle–foot orthoses: A literature review

paper_content:

BACKGROUND ::: The use of knee-ankle-foot orthoses with drop locked knee joints produces some limitations for walking in subjects with quadriceps muscle weakness. The development of stance control orthoses can potentially improve their functionality. ::: ::: ::: OBJECTIVES ::: The aim of this review was to compare the evidence of the effect of stance control orthoses to knee-ankle-foot orthoses with drop locked knee joints in improving kinematic variables and energy efficiency of walking by subjects with quadriceps muscle weakness caused by different pathologies. ::: ::: ::: STUDY DESIGN ::: Literature review. ::: ::: ::: METHODS ::: Based on selected keywords and their composition, a search was performed in Google Scholar, PubMed, ScienceDirect, and ISI Web of Knowledge databases. In total, 18 articles were finally chosen for review. ::: ::: ::: RESULTS ::: The results of this study demonstrated that this type of orthosis can improve the walking parameters of subjects with quadriceps muscle weakness and spinal cord injury patients when compared to a locked knee-ankle-foot orthosis. ::: ::: ::: CONCLUSION ::: There is evidence to show that stance control orthosis designs improve the gait kinematics but not energetic of knee-ankle-foot orthosis users. Development of new designs of stance control orthoses to provide a more normal pattern of walking is still required. ::: ::: ::: CLINICAL RELEVANCE ::: Stance control orthoses are a new generation of orthotic intervention that could potentially be significant in assisting to improve the gait kinematics by knee-ankle-foot orthosis users.
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paper_title: Biomechanical and energetic effects of a stance-control orthotic knee joint

paper_content:

Users of traditional knee-ankle-foot orthoses (KAFOs) walk with either locked or unlocked knee joints depending on the level of stability required. Some users may benefit from new stance-control KAFOs that prevent stance-phase knee flexion but allow swing-phase flexion. We collected data from nine nondisabled adults who walked with KAFOs that incorporated the Horton Stance-Control Orthotic Knee Joint (SCOKJ) in the locked, unlocked, and auto (which provides knee stability during stance phase and knee flexion during swing phase) modes to investigate the biomechanical and energetic effects of stance-control orthoses. Studying nondisabled subjects allowed us to analyze the effects of stance-control orthoses in a homogenous population. In general, gait kinematics for the auto and unlocked modes were more similar than for the auto and locked modes. Despite the elimination of hip hiking in the auto mode, oxygen cost was not different between the auto and locked modes (p > 0.99). The SCOKJ allowed our nondisabled subjects to walk with a more normal gait pattern; however, future research should explore the effect of stance-control orthoses on persons with gait pathology.
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paper_title: Engineering design review of stance-control knee-ankle-foot orthoses.

paper_content:

Persons with quadriceps muscle weakness are often prescribed a knee-ankle-foot orthosis that locks the knee in full extension during both stance and swing phases of gait. Locking the knee results in abnormal gait patterns characterized by hip hiking and leg circumduction during swing. The stance-control knee-ankle-foot orthosis (SCKAFO), a new type of orthosis, has emerged that permits free knee motion during swing while resisting knee flexion during stance, thereby supporting the limb during weight-bearing. This article examines various SCKAFO designs, discuss the existing design limitations, and identify remaining design challenges. Several commercial SCKAFOs have been released that incorporate different locking mechanisms. Preliminary gait studies have shown some devices to be promising; however, an important functional limitation in some SCKAFOs is dependence on specific joint angles to switch between stance and swing modes. Important design factors such as size, weight, and noise must be considered in new orthosis designs to ensure wide consumer acceptance.
---
paper_title: State of the Art Review of Knee–Ankle–Foot Orthoses

paper_content:

Knee–ankle–foot orthoses (KAFOs) are used to assist in ambulation. The purpose of this paper is to review existing KAFO designs which can be grouped into passive KAFOs, stance control (SC) KAFOs, and dynamic KAFOs. The conventional passive KAFOs do not provide any active control for knee motions. SCKAFOs lock the knee joint during the stance phase and allow free rotations during the swing phase. Some SCKAFOs switch between the stance and swing phases using body posture, while others use some kind of a control system to perform this switch. Finally, dynamic KAFOs control the knee joint during both stance and swing phases. Four dynamic systems are identified in the literature that use pneumatics, linear springs, hydraulics, and torsional rods made of superelastic alloys to control the knee joint during the gait cycle. However, only the two systems that use linear springs and torsional rods can reproduce the normal knee stiffness pattern which has two distinct characteristics: a soft stiffness during the swing phase and a hard stiffness during the stance phase. This review indicates that there is a need to conduct research regarding new KAFO designs that duplicate normal knee function during the whole gait cycle.
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paper_title: The gait and energy efficiency of stance control knee–ankle–foot orthoses: A literature review

paper_content:

BACKGROUND ::: The use of knee-ankle-foot orthoses with drop locked knee joints produces some limitations for walking in subjects with quadriceps muscle weakness. The development of stance control orthoses can potentially improve their functionality. ::: ::: ::: OBJECTIVES ::: The aim of this review was to compare the evidence of the effect of stance control orthoses to knee-ankle-foot orthoses with drop locked knee joints in improving kinematic variables and energy efficiency of walking by subjects with quadriceps muscle weakness caused by different pathologies. ::: ::: ::: STUDY DESIGN ::: Literature review. ::: ::: ::: METHODS ::: Based on selected keywords and their composition, a search was performed in Google Scholar, PubMed, ScienceDirect, and ISI Web of Knowledge databases. In total, 18 articles were finally chosen for review. ::: ::: ::: RESULTS ::: The results of this study demonstrated that this type of orthosis can improve the walking parameters of subjects with quadriceps muscle weakness and spinal cord injury patients when compared to a locked knee-ankle-foot orthosis. ::: ::: ::: CONCLUSION ::: There is evidence to show that stance control orthosis designs improve the gait kinematics but not energetic of knee-ankle-foot orthosis users. Development of new designs of stance control orthoses to provide a more normal pattern of walking is still required. ::: ::: ::: CLINICAL RELEVANCE ::: Stance control orthoses are a new generation of orthotic intervention that could potentially be significant in assisting to improve the gait kinematics by knee-ankle-foot orthosis users.
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paper_title: Development of a Dynamic Knee Actuator for a KAFO Using Superelastic Alloys

paper_content:

A knee-ankle-foot orthosis (KAFO), which covers the knee, ankle and foot, can mitigate abnormal walking pattern caused by weak quadriceps. Several types of KAFOs are currently available in the market: passive KAFOs, stance-control KAFOs and dynamic KAFOs. In passive KAFOs, the knee joint keeps being locked during standing and walking, and can be unlocked manually to allow free rotation for sitting. Stance-control KAFOs (SCKAFOs) allow free knee motion during swing phase when the braced leg is unloaded. Dynamic KAFOs are able to reproduce normal walking ability throughout whole gait cycle. This research is directed at using superelastic alloys to develop a dynamic knee actuator that can be mounted on a traditional passive KAFO. The actuator stiffness can match that of a normal knee joint during the walking gait cycle. This proposed knee actuator utilizes a storing-releasing energy method to apply functional compensation to the knee joint, controlling the knee joint during both stance and swing phases. Fundamentally, the knee actuator is composed of two distinct parts which are connected with the thigh and shank segments, respectively. There are two superelastic actuators that are housed within these two parts and activated independently. Each actuator is developed by combining a superelastic rod and a rotary spring in series. When neither actuator is engaged, the knee joint is allowed to rotate freely. The stance actuator works only in the stance phase and the swing actuator is active for the swing phase. The conceptual design of the knee actuator is verified using numerical simulation and a prototype is developed through additive manufacturing for confirming the concept.Copyright © 2014 by ASME
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paper_title: Biomechanical and energetic effects of a stance-control orthotic knee joint

paper_content:

Users of traditional knee-ankle-foot orthoses (KAFOs) walk with either locked or unlocked knee joints depending on the level of stability required. Some users may benefit from new stance-control KAFOs that prevent stance-phase knee flexion but allow swing-phase flexion. We collected data from nine nondisabled adults who walked with KAFOs that incorporated the Horton Stance-Control Orthotic Knee Joint (SCOKJ) in the locked, unlocked, and auto (which provides knee stability during stance phase and knee flexion during swing phase) modes to investigate the biomechanical and energetic effects of stance-control orthoses. Studying nondisabled subjects allowed us to analyze the effects of stance-control orthoses in a homogenous population. In general, gait kinematics for the auto and unlocked modes were more similar than for the auto and locked modes. Despite the elimination of hip hiking in the auto mode, oxygen cost was not different between the auto and locked modes (p > 0.99). The SCOKJ allowed our nondisabled subjects to walk with a more normal gait pattern; however, future research should explore the effect of stance-control orthoses on persons with gait pathology.
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paper_title: Design and Evaluation of a Knee Actuator for a Dynamic Knee-Ankle-Foot Orthosis

paper_content:

Dynamic KAFOs are developed to recover the normal walking ability during both stance and swing phases. Three types of dynamic KAFOs have been reported in the literature. Various actuation mechanisms including spring, pneumatic and hydraulic systems have been used. These devices can improve walking disability and compensate lower leg muscle deficiency. However, they are bulky, in some cases need complex control systems and do not recreate the normal gait pattern. These shortcomings have limited the application of dynamic KAFOs in daily life. The purpose of this paper is to develop a novel knee actuator for a dynamic KAFO that is actuated easily by employing shape memory materials. Such an actuation system makes the KAFO lightweight and has a greater potential to restore the normal gait. Torsional superelastic alloys are used in this actuator in order to match the stiffness of the knee joint of the KAFO with that of a normal knee joint during the walking gait cycle. There are two distinct parts in the knee actuator, acting independently to mimic the two phases of the gait cycle. One engages only in the stance phase and the other works in the swing phase. Each part is developed by combining a superelastic rod and a stiff rotary spring, in series. According to numerical simulation, such combination reproduces the varying knee stiffness during the whole walking gait. Also mechanical experiments have been conducted to further verify the conceptual design. The simulation and experimental results show that the actuator is able to reproduce the stiffness of the normal knee joint during the gait cycle.Copyright © 2014 by ASME
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paper_title: Engineering design review of stance-control knee-ankle-foot orthoses.

paper_content:

Persons with quadriceps muscle weakness are often prescribed a knee-ankle-foot orthosis that locks the knee in full extension during both stance and swing phases of gait. Locking the knee results in abnormal gait patterns characterized by hip hiking and leg circumduction during swing. The stance-control knee-ankle-foot orthosis (SCKAFO), a new type of orthosis, has emerged that permits free knee motion during swing while resisting knee flexion during stance, thereby supporting the limb during weight-bearing. This article examines various SCKAFO designs, discuss the existing design limitations, and identify remaining design challenges. Several commercial SCKAFOs have been released that incorporate different locking mechanisms. Preliminary gait studies have shown some devices to be promising; however, an important functional limitation in some SCKAFOs is dependence on specific joint angles to switch between stance and swing modes. Important design factors such as size, weight, and noise must be considered in new orthosis designs to ensure wide consumer acceptance.
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paper_title: A Dynamic Knee-Ankle-Foot Orthosis With Superelastic Actuators

paper_content:

A knee-ankle-foot orthosis (KAFO) spans the knee, ankle and foot, and assists in the walking motion of those who suffer neuromuscular deficiencies. KAFOs can be classified as passive, semi-dynamic and dynamic. Passive KAFOs lock the knee joint during the whole gait cycle. Semi dynamic KAFOs lock the knee joint during the stance phase. Dynamic KAFOs attempt to reproduce normal knee motions during the whole gait cycle. Two types of dynamic KAFOs have been reported in the literature. The first one is activated by using a pneumatic system, and the second one uses a spring mechanism. Both systems are bulky and controlled through complex control systems that limit their application as assistive devices. The purpose of our research is to develop a dynamic KAFO that is actuated easily by employing shape memory materials. Such an actuation system makes the KAFO lightweight and with a great commercialization potential. The purpose of this paper is to present a conceptual design for the knee actuator of a dynamic KAFO. This actuator uses torsional shape memory rods to match the stiffness of the knee joint of the KAFO with that of a normal knee joint during the walking gait cycle. Joint stiffness is measured by the moment around the joint per degree of joint rotation. The proposed actuator includes two parts that work independently during the two phases of the gait cycle. The first part engages only during the stance phase and the other works only during the swing phase. Each part is developed by combining a superelastic (SE) rod and a rotary spring in series. The conceptual design is verified by simulation. The simulation results show that the proposed knee actuator reproduces the stiffness of the normal knee joint during the whole gait cycle. It is thus possible to develop a novel dynamic KAFO that can provide normal knee stiffness characteristics to assist individuals with quadriceps deficiency.Copyright © 2013 by ASME
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paper_title: Stiffness Control of a SMA Actuator

paper_content:

This paper presents a control of stiffness for an actuator that utilizes the properties of shape memory alloy (SMA) wires. The control algorithm is developed based on angular position of the SMA actuated arm. The model for calculation of stiffness is prepared in MATLAB/Simulink environment. In this application, a PID controller is designed to regulate the applied voltage of the SMA wire. For all the experiments, dSPACE hardware-in-the-loop solution is used. Simulation and experimental results are collected to validate system model. Result show good performance and control of stiffness through PID control system.Copyright © 2009 by ASME
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paper_title: An Automated Testing Assembly for Characterizing Stiffness of an Ankle Foot Orthosis

paper_content:

An ankle foot orthosis (AFO) is a device that provides a controlled force to compensate for the muscle deficiencies in the ankle and helps normalize the gait of the patient. Evidence has indicated that there exists an optimal match correlating the patient’s gait related problems and the AFO stiffness. AFO ankle stiffness is measured by the moment around the ankle joint exerted by the AFO per degree of ankle joint rotation. To date, several testing devices and procedures have been developed to assess the stiffness characteristics of AFOs. Most of the devices are manually driven and may not exactly replicate human leg motion. Objective of developing an automated testing assembly is to identify stiffness characteristics of passive AFOs so as to develop an active AFO with shape memory alloy. We have developed an assembly using aluminum T-slotted profiles, single flange linear bearings, and living hinges from 80/20 Inc. Angle measurement was done by mounting Digital Protractor on the shank segment. The whole assembly was mounted on BOSE ElectroForce 3330 test instrument. dSPACE hardware-in-the-loop solution was used for real time data capture of force and angle sensor output. After assessing the characteristics of passive AFO we incorporated SMA wire in the AFO. Similar tests were conducted to evaluate effect of SMA wires on the overall stiffness of an AFO. The results confirm that SMA wires provide stiffness variation such a way that AAFO can be developed to achieve stiffness variation close to normal ankle stiffness.© 2011 ASME
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paper_title: Adaptive ankle–foot orthoses based on superelasticity of shape memory alloys

paper_content:

This article presents two innovative adaptive solutions for the ankle–foot orthosis based on mechanical and structural stiffness control of shape memory alloys. These concepts address gait abnormality in drop foot patients for various walking conditions such as different walking speeds. In the first design, a superelastic rod provides variable torsional stiffness that is adjusted by a controlled axial load. In the second design, the active length of superelastic hinge is adjusted in order to control the bending stiffness of the element. By adjusting the stiffness, variable level of compliance is achieved at the ankle. In both concepts, during powered plantarflexion in the stance phase of the gait, energy is stored in the shape memory alloy element. Release of this energy through superelasticity enables the ankle–foot orthosis to provide the desired controlled dorsiflexion motion in the sagittal plane and to raise the foot during the swing phase of the gait. The ultimate goal is to assist the patients in a...
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paper_title: Adaptive ankle–foot orthoses based on superelasticity of shape memory alloys

paper_content:

This article presents two innovative adaptive solutions for the ankle–foot orthosis based on mechanical and structural stiffness control of shape memory alloys. These concepts address gait abnormality in drop foot patients for various walking conditions such as different walking speeds. In the first design, a superelastic rod provides variable torsional stiffness that is adjusted by a controlled axial load. In the second design, the active length of superelastic hinge is adjusted in order to control the bending stiffness of the element. By adjusting the stiffness, variable level of compliance is achieved at the ankle. In both concepts, during powered plantarflexion in the stance phase of the gait, energy is stored in the shape memory alloy element. Release of this energy through superelasticity enables the ankle–foot orthosis to provide the desired controlled dorsiflexion motion in the sagittal plane and to raise the foot during the swing phase of the gait. The ultimate goal is to assist the patients in a...
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paper_title: New brace design combining CAD/CAM and biomechanical simulation for the treatment of adolescent idiopathic scoliosis.

paper_content:

BACKGROUND ::: A numerical based brace design platform, including biomechanical simulation, Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) was developed to rationalize braces for the treatment of adolescent idiopathic scoliosis. The objective of this study was to test the feasibility of the approach and assess the effectiveness of braces issued from this platform as compared to standard brace design. ::: ::: ::: METHODS ::: The biomechanical finite element model was built using the 3D reconstruction of the trunk skeleton from bi-planar radiographs and of the torso surface from surface topography. The finite element model is linked to a CAD/CAM software (Rodin4D), allowing the iterative design and simulation of the correction provided by the brace, as well as predicting pressures exerted on the torso. The resulting brace design was then fabricated using a numerical controlled carver. A brace designed using this platform (New Brace) as well as a standard thoraco-lumbo-sacral orthosis (Standard Brace) were built for six scoliotic patients. Both brace effectiveness was assessed using radiographs and compared to the simulations. ::: ::: ::: FINDINGS ::: The New Brace corrected on average the spine deformities within 5° of Cobb angle of the simulated correction and with a similar correction as compared to the Standard Brace (average correction of 16° vs. 11° (MT); P=0.1 and 13° vs. 16° (TL/L); P=0.5 for the Standard Brace and the New Brace respectively). The two braces had a similar 10° lordosing effect of the thoracic curve. The coronal balance was quite similar (7.3 vs. 6.8mm balance improvement respectively for New Brace vs. Standard Brace). ::: ::: ::: INTERPRETATION ::: These first clinical results showed the feasibility of building computer-assisted braces, equivalent to standard orthosis. An extended study on more cases is under way to fully assess this new design paradigm, which in the long term would allow improving brace design and rationalize the conservative treatments of scoliosis.
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paper_title: A randomized double-blinded clinical trial to evaluate the safety and efficacy of a novel superelastic nickel–titanium spinal rod in adolescent idiopathic scoliosis: 5-year follow-up

paper_content:

Purpose ::: To evaluate the safety and efficacy of a superelastic shape-memory alloy (SNT) rod used in the treatment of adolescent idiopathic scoliosis (AIS).
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paper_title: Shape Memory Actuators for Medical Rehabilitation and Neuroscience

paper_content:

Actuators based on shape memory alloys (SMA) proved to be particularly advantageous with respect to other actuation technologies when they are embedded in applications requiring strict compliance to a set of compatibility (e.g. mechanical, biological, weight, ...) and environmental constraints. Most noteworthy are the uses in miniaturised components, lightweight systems, sensing-actuating systems (e.g. actuators interacting with changing environmental variables), low-noise or low-impact appliances (e.g. actuators with reduced interaction with the environment) and self-sensing controllable devices. With particular regard to these preferred applications, SMA can also play a role in solving specific actuation problems in the fields of Medical Rehabilitation and Neuroscience. The main characteristics expected of SMA actuators for these fields are light weight and portability; self-adjustment to evolving needs; applicability of actuation in shielded environments (with bioimaging and diagnostic devices: magnetic resonance imaging (MRI, fMRI), magnetoencephalography (MEG), and the like).
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paper_title: Precise position control of shape memory alloy–actuated continuum modules through fuzzy algorithm

paper_content:

Development of a fuzzy precise controller for the continuum modules utilizing shape memory alloy actuators is the main focus of this study. To this end, two continuum and flexible shape memory allo...
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paper_title: Developing a novel continuum module actuated by shape memory alloys

paper_content:

Abstract Developing continuum manipulators is very useful for special robotic applications. One of the practical usages is medical tools such as endoscope or colonscope. In such applications, a maneuverable thin and flexible manipulator is highly required. In this paper, a basic module is designed which can be used as an element of a continuum manipulator in a modular configuration. Furthermore, the module can simultaneously be utilized both as a joint and actuator in a mechanism. In the structure of the module, three springs of shape memory alloy (SMA) are uniformly distributed and mounted around a bias spring with an angle of 120°. Stimulating SMA springs individually or together provides different rotation regimes. Brinson model and normal compression spring behavior are used for modeling of SMA and bias spring, respectively. Afterward, the model of SMAs and bias spring are integrated to describe the behavior of the actuated module. The modeled module is simulated in Matlab software by which the proper control strategy can be designed. Due to the complex and nonlinear behavior of SMAs, design an appropriate control scheme is a real challenge. In this paper, a new control strategy is developed for regulating a desired position for the two degrees of freedom actuator module. Through the provided test bed, the performance of the strategy is verified. The results present a reasonable performance of the controller and reveal the merits of the developed module in continuum robotic manipulators or flexible joint actuator.
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paper_title: Adaptive ankle–foot orthoses based on superelasticity of shape memory alloys

paper_content:

This article presents two innovative adaptive solutions for the ankle–foot orthosis based on mechanical and structural stiffness control of shape memory alloys. These concepts address gait abnormality in drop foot patients for various walking conditions such as different walking speeds. In the first design, a superelastic rod provides variable torsional stiffness that is adjusted by a controlled axial load. In the second design, the active length of superelastic hinge is adjusted in order to control the bending stiffness of the element. By adjusting the stiffness, variable level of compliance is achieved at the ankle. In both concepts, during powered plantarflexion in the stance phase of the gait, energy is stored in the shape memory alloy element. Release of this energy through superelasticity enables the ankle–foot orthosis to provide the desired controlled dorsiflexion motion in the sagittal plane and to raise the foot during the swing phase of the gait. The ultimate goal is to assist the patients in a...
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Title: Application of NiTi in Assistive and Rehabilitation Devices: A Review

Section 1: Introduction
Description 1: Introduce the concept of shape memory alloys (SMAs) and their relevance to assistive and rehabilitation devices.

Section 2: SMAs in Assistive Devices
Description 2: Discuss how SMAs are used in assistive devices, focusing on examples like prosthetic and orthotic devices.

Section 3: Prosthesis
Description 3: Explore various prosthetic devices utilizing SMAs, including detailed case studies like those developed by Y. Nakano, K. Andrianesis, A. Tzes, H. Taniguchi, and Jae H. Lee et al.

Section 4: Orthosis
Description 4: Examine different types of orthotic devices that use SMAs, including specific applications for elbows, knees, and ankles.

Section 5: SMA Orthotic Devices for Elbow
Description 5: Detail applications of SMAs in orthotic devices for elbows, citing studies by Pittaccio et al. and others.

Section 6: SMA Orthotic Devices for Knee
Description 6: Describe the use of SMAs in knee orthotic devices, referencing work by Feng et al.

Section 7: SMA Orthotic Devices for Ankle
Description 7: Discuss the implementation of SMAs in ankle orthotic devices, with examples from researchers like Bhadane et al., Deberg et al., and Amerinatanzi et al.

Section 8: Orthosis for Correcting Deformities and Abnormal Postures
Description 8: Cover the use of SMAs in devices designed to correct deformities and maintain proper posture, including specific applications for digits and the spine.

Section 9: SMAs in Rehabilitation Devices
Description 9: Highlight how SMAs are utilized in rehabilitation devices to treat movement disorders and facilitate recovery.

Section 10: Discussion
Description 10: Analyze and summarize the benefits and challenges of using SMAs in prosthetic, orthotic, and rehabilitation devices.

Section 11: Conclusions
Description 11: Provide concluding remarks on the current state and future potential of NiTi SMAs in biomedical applications.