An Overview of Humanoid Robots Technologies
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paper_title: Design Approach of Biologically-Inspired Musculoskeletal Humanoids

paper_content:

In order to realize more natural and various motions like humans, humanlike musculoskeletal tendon-driven humanoids have been studied. Especially, it is very challenging to design musculoskeletal body structure which consists of complicated bones, redundant powerful and flexible muscles, and large number of distributed sensors. In addition, it is very challenging to reveal humanlike intelligence to manage these complicated musculoskeletal body structure. This paper sums up life-sized musculoskeletal humanoids Kenta, Kotaro, Kenzoh and Kenshiro which we have developed so far, and describes key technologies to develop and control these robots.
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paper_title: Design and Realization of a Humanoid Robot for Fast and Autonomous Bipedal Locomotion

paper_content:

This thesis covers the mechatronic conception, design and realization of a humanoid walking robot. Weighing approximately 60 kg, the robot stands 180 cm tall and has 25 actuated degrees of freedom in a redundant configuration. The mechanical structure is characterized by the consistent lightweight design with high effective stiffness. The lightweight servo actuators combine high-dynamic brushless servo motors with precision gearings and sensors into a compact package. Moreover, the resultant inertia of the legs is minimized by a sophisticated design of the structure and drive mechanisms, resulting in a superior acceleration behavior. The sensor layout comprises angular sensors for direct measurement of the joint angles, a high-precision inertial measurement system and force/torque sensors in the feet. Using the trajectory generation and control system, which is not in the scope of this work, the current speed of locomotion is 3.34 km/h.
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paper_title: Humanoid robot HRP-4 - Humanoid robotics platform with lightweight and slim body

paper_content:

This paper presents the development of humanoid robotics platform - 4 (or HRP-4 for short). The high-density implementation used for HRP-4C, the cybernetic human developed by AIST, is also applied to HRP-4. HRP-4 has a total of 34 degrees of freedom, including 7 degrees of freedom for each arm to facilitate object handling and has a slim, lightweight body with a height of 151 [cm] and weight 39 [kg]. The software platform OpenRTM-aist and a Linux kernel with the RT-Preempt patch are used in the HRP-4 software system. Design concepts and mechanisms are presented with its basic specification in this paper.
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paper_title: Design and Realization of a Humanoid Robot for Fast and Autonomous Bipedal Locomotion

paper_content:

This thesis covers the mechatronic conception, design and realization of a humanoid walking robot. Weighing approximately 60 kg, the robot stands 180 cm tall and has 25 actuated degrees of freedom in a redundant configuration. The mechanical structure is characterized by the consistent lightweight design with high effective stiffness. The lightweight servo actuators combine high-dynamic brushless servo motors with precision gearings and sensors into a compact package. Moreover, the resultant inertia of the legs is minimized by a sophisticated design of the structure and drive mechanisms, resulting in a superior acceleration behavior. The sensor layout comprises angular sensors for direct measurement of the joint angles, a high-precision inertial measurement system and force/torque sensors in the feet. Using the trajectory generation and control system, which is not in the scope of this work, the current speed of locomotion is 3.34 km/h.
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paper_title: Poppy humanoid platform: Experimental evaluation of the role of a bio-inspired thigh shape

paper_content:

In this paper, we present an experimental evaluation of the role of the morphology in the Poppy humanoid platform. More precisely, we have investigated the impact of the bio-inspired thigh, bended of 6°, on the balance and biped locomotion. We compare this design with a more traditional straight thigh. We describe both the theoretical model and real experiments showing that the bio-inspired thigh allows the reduction of falling speed by almost 60% (single support phase) and the decrease of the lateral motion needed for the mass transfer from one foot to the other by 30% (double support phase). We also present an experiment where the robot walks on a treadmill thanks to the social and physical guidance of expert users and we show that the bended thigh reduces the upper body motion by about 45% indicating a more stable walk.
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paper_title: Humanoid robot HRP-4 - Humanoid robotics platform with lightweight and slim body

paper_content:

This paper presents the development of humanoid robotics platform - 4 (or HRP-4 for short). The high-density implementation used for HRP-4C, the cybernetic human developed by AIST, is also applied to HRP-4. HRP-4 has a total of 34 degrees of freedom, including 7 degrees of freedom for each arm to facilitate object handling and has a slim, lightweight body with a height of 151 [cm] and weight 39 [kg]. The software platform OpenRTM-aist and a Linux kernel with the RT-Preempt patch are used in the HRP-4 software system. Design concepts and mechanisms are presented with its basic specification in this paper.
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paper_title: Vertical vibration suppression for a position controlled biped robot

paper_content:

A controller design to suppress vertical vibration of a position controlled biped walking robot is presented. The system model of structural vibration is estimated from a measurement of frequency response. By using the model, an optimal feedback controller with full state observer is designed. With a consideration of leg support phase, the vibration controller is combined into our walking controller. The effectiveness of our controller is experimentally demonstrated.
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paper_title: COMpliant huMANoid COMAN: Optimal joint stiffness tuning for modal frequency control

paper_content:

The incorporation of passive compliance in robotic systems could improve their performance during interactions and impacts, for energy storage and efficiency, and for general safety for both the robots and humans. This paper presents the recently developed COMpliant huMANoid COMAN. COMAN is actuated by passive compliance actuators based on the series elastic actuation principle (SEA). The design and implementation of the overall body of the robot is discussed including the realization of the different body segments and the tuning of the joint distributed passive elasticity. This joint stiffness tuning is a critical parameter in the performance of compliant systems. A novel systematic method to optimally tune the joint elasticity of multi-dof SEA robots based on resonance analysis and energy storage maximization criteria forms one of the key contributions of this work. The paper will show this method being applied to the selection of the passive elasticity of COMAN legs. The first completed robot prototype is presented accompanied by experimental walking trials to demonstrate its operation.
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paper_title: Design and Realization of a Humanoid Robot for Fast and Autonomous Bipedal Locomotion

paper_content:

This thesis covers the mechatronic conception, design and realization of a humanoid walking robot. Weighing approximately 60 kg, the robot stands 180 cm tall and has 25 actuated degrees of freedom in a redundant configuration. The mechanical structure is characterized by the consistent lightweight design with high effective stiffness. The lightweight servo actuators combine high-dynamic brushless servo motors with precision gearings and sensors into a compact package. Moreover, the resultant inertia of the legs is minimized by a sophisticated design of the structure and drive mechanisms, resulting in a superior acceleration behavior. The sensor layout comprises angular sensors for direct measurement of the joint angles, a high-precision inertial measurement system and force/torque sensors in the feet. Using the trajectory generation and control system, which is not in the scope of this work, the current speed of locomotion is 3.34 km/h.
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paper_title: Team RoboSimian: Semi-autonomous Mobile Manipulation at the 2015 DARPA Robotics Challenge Finals

paper_content:

This paper discusses hardware and software improvements to the RoboSimian system leading up to and during the 2015 DARPA Robotics Challenge DRC Finals. Team RoboSimian achieved a 5th place finish by achieving 7 points in 47:59 min. We present an architecture that was structured to be adaptable at the lowest level and repeatable at the highest level. The low-level adaptability was achieved by leveraging tactile measurements from force torque sensors in the wrist coupled with whole-body motion primitives. We use the term "behaviors" to conceptualize this low-level adaptability. Each behavior is a contact-triggered state machine that enables execution of short-order manipulation and mobility tasks autonomously. At a high level, we focused on a teach-and-repeat style of development by storing executed behaviors and navigation poses in an object/task frame for recall later. This enabled us to perform tasks with high repeatability on competition day while being robust to task differences from practice to execution.
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paper_title: Faster and Smoother Walking of Humanoid HRP-2 with Passive Toe Joints

paper_content:

This paper addresses the role of toe joints in increasing the walking speed of biped robots. It is worthy that adding a toe joint will increase the step length thanks to the additional degree of freedom. But, the originality of this work is that longer steps are obtained thanks to an under-actuated phase and an appropriate ZMP trajectory. The simulations showed that adding passive toe joints allows smoother and 1.5 faster walking.
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paper_title: CHIMP, the CMU Highly Intelligent Mobile Platform

paper_content:

We have developed the CHIMP CMU Highly Intelligent Mobile Platform robot as a platform for executing complex tasks in dangerous, degraded, human-engineered environments. CHIMP has a near-human form factor, work-envelope, strength, and dexterity to work effectively in these environments. It avoids the need for complex control by maintaining static rather than dynamic stability. Utilizing various sensors embedded in the robot's head, CHIMP generates full three-dimensional representations of its environment and transmits these models to a human operator to achieve latency-free situational awareness. This awareness is used to visualize the robot within its environment and preview candidate free-space motions. Operators using CHIMP are able to select between task, workspace, and joint space control modes to trade between speed and generality. Thus, they are able to perform remote tasks quickly, confidently, and reliably, due to the overall design of the robot and software. CHIMP's hardware was designed, built, and tested over 15i¾?months leading up to the DARPA Robotics Challenge. The software was developed in parallel using surrogate hardware and simulation tools. Over a six-week span prior to the DRC Trials, the software was ported to the robot, the system was debugged, and the tasks were practiced continuously. Given the aggressive schedule leading to the DRC Trials, development of CHIMP focused primarily on manipulation tasks. Nonetheless, our team finished 3rd out of 16. With an upcoming year to develop new software for CHIMP, we look forward to improving the robot's capability and increasing its speed to compete in the DRC Finals.
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paper_title: Humanoid robot HRP-2Kai — Improvement of HRP-2 towards disaster response tasks

paper_content:

This paper presents a humanoid robot HRP-2Kai, which is the improvement version of HRP-2 towards disaster response tasks. HRP-2 stands for a humanoid robotics platform-2, which was developed in phase two of the Japanese national project HRP (Humanoid Robotics Project, from 1998FY to 2002FY), while Kai means improvement in Japanese. In a year of the ninth year from releasing HRP-2, the Great East Japan Earthquake shook Japan on March 11, 2011. Since we reflected on that we were not able to deploy our robots for emergency response at that time, we started a study of the disaster response humanoid robots by improving HRP-2. Improvements are presented with its basic specification in this paper.
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paper_title: Whole-body model-predictive control applied to the HRP-2 humanoid

paper_content:

Controlling the robot with a permanently-updated optimal trajectory, also known as model predictive control, is the Holy Grail of whole-body motion generation. Before obtaining it, several challenges should be faced: computation cost, non-linear local minima, algorithm stability, etc. In this paper, we address the problem of applying the updated optimal control in real-time on the physical robot. In particular, we focus on the problems raised by the delays due to computation and by the differences between the real robot and the simulated model. Based on the optimal-control solver MuJoCo, we implemented a complete model-predictive controller and we applied it in real-time on the physical HRP-2 robot. It is the first time that such a whole-body model predictive controller is applied in real-time on a complex dynamic robot. Aside from the technical contributions cited above, the main contribution of this paper is to report the experimental results of this premiere implementation.
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paper_title: TALOS: A new humanoid research platform targeted for industrial applications

paper_content:

The upcoming generation of humanoid robots will have to be equipped with state-of-the-art technical features along with high industrial quality, but they should also offer the prospect of effective physical human interaction. In this paper we introduce a new humanoid robot capable of interacting with a human environment and targeting industrial applications. Limitations are outlined and used together with the feedback from the DARPA Robotics Challenge, and other teams leading the field in creating new humanoid robots. The resulting robot is able to handle weights of 6 kg with an out-stretched arm, and has powerful motors to carry out fast movements. Its kinematics have been specially designed for screwing and drilling motions. In order to make interaction with human operators possible, this robot is equipped with torque sensors to measure joint effort and high resolution encoders to measure both motor and joint positions. The humanoid robotics field has reached a stage where robustness and repeatability is the next watershed. We believe that this robot has the potential to become a powerful tool for the research community to successfully navigate this turning point, as the humanoid robot HRP-2 was in its own time.
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paper_title: Design, realization and sensorization of the dexterous iCub hand

paper_content:

In this paper we describe the hand of the humanoid iCub, an open source robotic platform funded by the European Commission. The principal design rationale was the necessity to supply the robot with sufficiently dexterous and sensorized hands in order to study complex skills such as manipulation. The final design has 9 actuators for each hand, 12 tactile sensors at each fingertip, 48 pressure sensors in the palm and 17 position sensors. The electronics for the sensors are embedded in the hand. As a preliminary application we tested the hand in a simplified grasping scenario in order to quantitatively evaluate the reliability and repeatability of the overall system.
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paper_title: A versatile and efficient pattern generator for generalized legged locomotion

paper_content:

This paper presents a generic and efficient approach to generate dynamically consistent motions for under-actuated systems like humanoid or quadruped robots. The main contribution is a walking pattern generator, able to compute a stable trajectory of the center of mass of the robot along with the angular momentum, for any given configuration of contacts (e.g. on uneven, sloppy or slippery terrain, or with closed-gripper). Unlike existing methods, our solver is fast enough to be applied as a model-predictive controller. We then integrate this pattern generator in a complete framework: an acyclic contact planner is first used to automatically compute the contact sequence from a 3D model of the environment and a desired final posture; a stable walking pattern is then computed by the proposed solver; a dynamically-stable whole-body trajectory is finally obtained using a second-order hierarchical inverse kinematics. The implementation of the whole pipeline is fast enough to plan a step while the previous one is executed. The interest of the method is demonstrated by real experiments on the HRP-2 robot, by performing long-step walking and climbing a staircase with handrail support.
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paper_title: Hardware improvement of Cybernetic Human HRP-4C for entertainment use

paper_content:

Hardware improvement of cybernetic human HRP-4C for entertainment is presented in this paper. We coined the word “Cybernetic Human” to explain a humanoid robot with a realistic head and a realistic figure of a human being. HRP-4C stands for Humanoid Robotics Platform-4 (Cybernetic human). Its joints and dimensions conform to average values of young Japanese females and HRP-4C looks very human-like. We have made HRP-4C present in several events to search for a possibility of use in the entertainment industry. Based on feedback from our experience, we improved its hardware. The new hand, the new foot with active toe joint, and the new eye with camera are introduced.
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paper_title: DLR-Hand II: next generation of a dextrous robot hand

paper_content:

This paper outlines the 2nd generation of multisensory hand design at DLR, based on the results of the DLR Hand I we analysed. An open skeleton structure for better maintenance with semi-shell housing and the new automatically reconfigurable palm have been equipped with more powerful actuators to reach 30 N on the fingertip. The newly designed sensors as the 6-DOF fingertip force torque sensor, the integrated electronics and the new communication architecture with a reduction of cabling to the hand to only 12 lines, are outlined. The Cartesian impedance control of all the fingers completes the new 13-DOF hand.
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paper_title: Constraint-based dynamics simulator for humanoid robots with shock absorbing mechanisms

paper_content:

We propose a simulation system that achieves realistic and efficient simulations of humanoid robots. This paper focuses on a constraint-based contact force solver and virtual spring-damper joints from among the components of the system. The contact force solver can accurately simulate contacts between rigid bodies including articulated rigid bodies. LCP-like formulation of constraint conditions is solved by an iterative calculation method that extends the Gauss-Seidel method. This paper clarifies how to integrate existing methods to implement a robust and efficient solver. Virtual spring-damper joints are proposed to simulate a shock absorbing mechanism that many biped humanoid robots have in their feet to increase the stability of walking motion. The combination of the rigid contact model and the elastic virtual joints can improve the accuracy of the simulation. The simulation system was verified by experiments using humanoid robot HRP-2, and the results shows the validity of the system.
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paper_title: ZMP-based Biped Running Enhanced by Toe Springs

paper_content:

We discuss a ZMP-based running pattern generation for a biped robot equipped with toe springs. Our biped robot HRP-2LT has twelve active DoFs for its legs and two passive DoFs for its toes. The trajectory of the center of mass is designed to realize the specified running motion and the foot trajectories are determined to get proper spring action at lift off phases. They are interpreted into joint angles by using the resolved momentum control. By the simulation and the preliminary experiment, it is shown that the toe springs are effectively used for running and hopping.
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paper_title: Faster and Smoother Walking of Humanoid HRP-2 with Passive Toe Joints

paper_content:

This paper addresses the role of toe joints in increasing the walking speed of biped robots. It is worthy that adding a toe joint will increase the step length thanks to the additional degree of freedom. But, the originality of this work is that longer steps are obtained thanks to an under-actuated phase and an appropriate ZMP trajectory. The simulations showed that adding passive toe joints allows smoother and 1.5 faster walking.
---
paper_title: Design and Realization of a Humanoid Robot for Fast and Autonomous Bipedal Locomotion

paper_content:

This thesis covers the mechatronic conception, design and realization of a humanoid walking robot. Weighing approximately 60 kg, the robot stands 180 cm tall and has 25 actuated degrees of freedom in a redundant configuration. The mechanical structure is characterized by the consistent lightweight design with high effective stiffness. The lightweight servo actuators combine high-dynamic brushless servo motors with precision gearings and sensors into a compact package. Moreover, the resultant inertia of the legs is minimized by a sophisticated design of the structure and drive mechanisms, resulting in a superior acceleration behavior. The sensor layout comprises angular sensors for direct measurement of the joint angles, a high-precision inertial measurement system and force/torque sensors in the feet. Using the trajectory generation and control system, which is not in the scope of this work, the current speed of locomotion is 3.34 km/h.
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paper_title: Humanoid robot HRP-3

paper_content:

A development of humanoid robot HRP-2 is presented in this paper. HRP-2 is a humanoid robotics platform, which we developed in phase two of HRP. HRP was a humanoid robotics project, which had run by the Ministry of Economy, Trade and Industry (METI) of Japan from 1998FY to 2002FY for five years. The ability of the biped locomotion of HRP-2 is improved so that HRP-2 can cope with uneven surface, can walk at two third level of human speed, and can walk on a narrow path. The ability of whole body motion of HRP-2 is also improved so that HRP-2 can get up by a humanoid robot's own self if HRP-2 tips over safely. In this paper, the appearance design, the mechanisms, the electrical systems, specifications, and features upgraded from its prototype are also introduced.
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paper_title: Design and Realization of a Humanoid Robot for Fast and Autonomous Bipedal Locomotion

paper_content:

This thesis covers the mechatronic conception, design and realization of a humanoid walking robot. Weighing approximately 60 kg, the robot stands 180 cm tall and has 25 actuated degrees of freedom in a redundant configuration. The mechanical structure is characterized by the consistent lightweight design with high effective stiffness. The lightweight servo actuators combine high-dynamic brushless servo motors with precision gearings and sensors into a compact package. Moreover, the resultant inertia of the legs is minimized by a sophisticated design of the structure and drive mechanisms, resulting in a superior acceleration behavior. The sensor layout comprises angular sensors for direct measurement of the joint angles, a high-precision inertial measurement system and force/torque sensors in the feet. Using the trajectory generation and control system, which is not in the scope of this work, the current speed of locomotion is 3.34 km/h.
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paper_title: Proprioceptive Actuator Design in the MIT Cheetah: Impact Mitigation and High-Bandwidth Physical Interaction for Dynamic Legged Robots

paper_content:

Designing an actuator system for highly dynamic legged robots has been one of the grand challenges in robotics research. Conventional actuators for manufacturing applications have difficulty satisfying design requirements for high-speed locomotion, such as the need for high torque density and the ability to manage dynamic physical interactions. To address this challenge, this paper suggests a proprioceptive actuation paradigm that enables highly dynamic performance in legged machines. Proprioceptive actuation uses collocated force control at the joints to effectively control contact interactions at the feet under dynamic conditions. Modal analysis of a reduced leg model and dimensional analysis of DC motors address the main principles for implementation of this paradigm. In the realm of legged machines, this paradigm provides a unique combination of high torque density, high-bandwidth force control, and the ability to mitigate impacts through backdrivability. We introduce a new metric named the “impact mitigation factor” (IMF) to quantify backdrivability at impact, which enables design comparison across a wide class of robots. The MIT Cheetah leg is presented, and is shown to have an IMF that is comparable to other quadrupeds with series springs to handle impact. The design enables the Cheetah to control contact forces during dynamic bounding, with contact times down to 85 ms and peak forces over 450 N. The unique capabilities of the MIT Cheetah, achieving impact-robust force-controlled operation in high-speed three-dimensional running and jumping, suggest wider implementation of this holistic actuation approach.
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paper_title: Posture and balance control for biped robots based on contact force optimization

paper_content:

This paper presents a new balancing control approach for regulating the center of mass position and trunk orientation of a bipedal robot in a compliant way. The controller computes a desired wrench (force and torque) required to recover the posture when an unknown external perturbation has changed the posture of the robot. This wrench is later distributed as forces at predefined contact points via a constrained optimization, which aims at achieving the desired wrench while minimizing the Euclidean norm of the contact forces. The formulation of the force distribution as an optimization problem is adopted from the grasping literature and allows to consider restrictions coming from the friction between the contact points and the ground.
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paper_title: Design of high torque and high speed leg module for high power humanoid

paper_content:

The high power ability of humanoid is desired for application of nursing or running or jumping motions. Achievement of the actuator of light and powerful equivalent to humans is required. In this paper, we propose a method to extract inherent performance from motors by an active temperature control. The method safely improves the output of motors. The active temperature control is achieved by combining the estimation of an internal temperature of the motor with the forced cooling by liquid. We also developed high power motor drivers for the proposed method. An experiment of a high power joint test bench is shown. In this paper, we show a high power prototype biped robot for application of nursing, running or jumping motions. High power actuator system and robust internal body network are developed for high power robot. Basic demonstration experiments of high power motion are shown.
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paper_title: CB: A Humanoid Research Platform for Exploring NeuroScience

paper_content:

This paper presents a 50 degrees of freedom humanoid robot, CB - Computational Brain. CB is a humanoid robot created for exploring the underlying processing of the human brain while dealing with the real world. We place our investigations within real world contexts, as humans do. In so doing, we focus on utilising a system that is closer to human - in sensing, configuration and performance. The real-time network-based control architecture for the control of all 50 degrees of freedom will be presented. The controller provides full position/velocity/force sensing and control at 1 KHz, allowing us the flexibility in deriving various forms of control schemes. Three aspects of the system are highlighted in this paper: 1) physical power for walking; 2) full-body compliant control - physical interactions; 3) perception and control - visual ocularmotor responses.
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paper_title: Evaluations on contribution of backdrivability and force measurement performance on force sensitivity of actuators

paper_content:

The importance of force measurement and back-drivability in realizing force sensitive actuator is widely acknowledged. There are studies on fidelity of torque sensors and backdrivability individually, but limited study are made on investigating effect of torque fidelity and backdrivability on force sensitivity of the actuation system. In this paper, we developed backdrivable electro-hydrostatic actuator equipped with torque sensor to analyze the effect of torque fidelity and backdrivability on force sensitive control system. We implemented friction compensation controller and evaluated force sensitivity of the actuator by residual friction torque after the friction compensation. Method using pressure sensor and torque sensor were compared. Effect of backdrivability was performed by comparing friction torque of Harmonic Drive joint and joint with developed actuator.
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paper_title: Development of an anthropomorphic hand for a mobile assistive robot

paper_content:

In this paper the mechanism, design, and control system of a new humanoid-type hand with human-like manipulation abilities is discussed. The hand is designed for the humanoid robot which has to work autonomously or interactively in cooperation with humans. The ideal end effector for such 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. The hand can perform most of human grasping types. In this paper, particular attention is dedicated to measurement analysis, technical characteristics, and functionality of the hand prototype. Furthermore, first experience gained from using hand prototypes on a humanoid robot is outlined.
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paper_title: Mowgli: A Bipedal Jumping and Landing Robot with an Artificial Musculoskeletal System

paper_content:

Jumping and landing movements are characterized by large instantaneous forces, short duration, and a high uncertainty concerning take off and landing points. Such characteristics make conventional types of control and robot design inadequate. Here we present an approach to realize motor control of jumping and landing which exploits the synergy between control and mechanical structure. Our experimental system is a pneumatically actuated bipedal robot called "Mowgli". Mowgli's artificial musculoskeletal system consists of six McKibben pneumatic muscle actuators including bi-articular muscle and two legs with hip, knee, and ankle joints. Mowgli can reach jump heights of more than 50% of its body height and can land softly. Our results show a proximo-distal sequence of joint extensions during jumping despite simultaneous motor activity. Extensions in the whole body motion are caused by the compliance and the natural dynamics of the legs. In addition to the experiments with the real robot, we also simulated two types of open loop controllers for vertical jumping with disturbance. We found that the model controlled by open loop motor command through a muscle-tendon mechanism could jump robustly. The simulation results demonstrate the contribution of the artificial musculoskeletal system as a physical feedback loop in explosive movements.
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paper_title: Trajectory Planning for the Walking Biped “Lucy”

paper_content:

A real-time joint trajectory generator for planar walking bipeds is proposed. In the near future this trajectory planner will be implemented on the robot "Lucy", which is actuated by pleated pneumatic artificial muscles. The trajectory planner generates dynamically stable motion patterns by using a set of objective locomotion parameters as its input, and by tuning and exploiting the natural upper body dynamics. The latter can be determined and manipulated by using the angular momentum equation. Basically, trajectories for hip and swing foot motion are generated, which guarantee that the objective locomotion parameters attain certain prescribed values. Additionally, the hip trajectories are slightly modified such that the upper body motion is steered naturally, meaning that it requires practically no actuation. This has the advantage that the upper body actuation hardly influences the position of the Zero Moment Point. The effectiveness of the strategy developed is demonstrated by simulation results. A first simulation is performed under the assumption of perfect tracking by the controllers of the different actuators. This allows one to verify the effectiveness of the trajectory planner and to evaluate the postural stability. A second simulation is performed while taking the control architecture of the real robot into account. In order to have a more realistic simulation the proposed control architecture is evaluated with a full hybrid dynamic simulation model of the biped "Lucy". This simulator combines the dynamical behaviour of the robot with the thermodynamical effects that take place in the muscle-valves actuation system. The observed hardware limitations of the real robot and expected model errors are taken into account in order to give a realistic qualitative evaluation of the control performance and to test the robustness.
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paper_title: Design of upper limb by adhesion of muscles and bones — Detail human mimetic musculoskeletal humanoid kenshiro

paper_content:

This paper presents a design methodology for humanoid upper limb based on human anatomy. Kenshiro is a full body tendon driven humanoid robot and is designed from the data of average 14 year old Japanese boy. The design of his upper limb is realizing detail features of muscles, bones and the adhesive relation of the two. Human mimetic design is realized by focusing on the fact that joints are being stabled by muscles winding around the bones, and by accurately mimicking the bone shape this was enabled. In this paper we also introduce details of mechanical specifications of the upper limb. By having muscles, bones, and joint structures based on human anatomy, Kenshiro can move flexibly. The use as human body simulator can be expected by measuring sensor data which can correspond to biological data.
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paper_title: COMpliant huMANoid COMAN: Optimal joint stiffness tuning for modal frequency control

paper_content:

The incorporation of passive compliance in robotic systems could improve their performance during interactions and impacts, for energy storage and efficiency, and for general safety for both the robots and humans. This paper presents the recently developed COMpliant huMANoid COMAN. COMAN is actuated by passive compliance actuators based on the series elastic actuation principle (SEA). The design and implementation of the overall body of the robot is discussed including the realization of the different body segments and the tuning of the joint distributed passive elasticity. This joint stiffness tuning is a critical parameter in the performance of compliant systems. A novel systematic method to optimally tune the joint elasticity of multi-dof SEA robots based on resonance analysis and energy storage maximization criteria forms one of the key contributions of this work. The paper will show this method being applied to the selection of the passive elasticity of COMAN legs. The first completed robot prototype is presented accompanied by experimental walking trials to demonstrate its operation.
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paper_title: A Running Controller of Humanoid Biped HRP-2LR

paper_content:

This article explains a control system, which stabilizes running biped robot HRP-2LR. The robot uses prescribed running pattern calculated by resolved momentum control, and a running controller stabilizes the system against disturbances. The running controller consists of posture stabilization, inverted pendulum stabilization, contact torque control, impact absorbing control, foot vertical force control and torque distribution control. Applying the proposed controller, HRP-2LR could successfully run with average speed of 0.16(m/s) repeating flight phase of 0.06 (s) and support phase of 0.3 (s).
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paper_title: Overview of the torque-controlled humanoid robot TORO

paper_content:

This paper gives an overview on the torque-controlled humanoid robot TORO, which has evolved from the former DLR Biped. In particular, we describe its mechanical design and dimensioning, its sensors, electronics and computer hardware. Additionally, we give a short introduction to the walking and multi-contact balancing strategies used for TORO.
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paper_title: Design and Control of a Variable Stiffness Actuator for Safe and Fast Physical Human/Robot Interaction

paper_content:

This paper is concerned with the design and control of actuators for machines and robots physically interacting with humans, implementing criteria established in our previous work [1] on optimal mechanical-control co-design for intrinsically safe, yet performant machines. In our Variable Impedance Actuation (VIA) approach, actuators control in real-time both the reference position and the mechanical impedance of the moving parts in the machine in such a way to optimize performance while intrinsically guaranteeing safety. In this paper we describe an implementation of such concepts, consisting of a novel electromechanical Variable Stiffness Actuation (VSA) motor. The design and the functioning principle of the VSA are reported, along with the analysis of its dynamic behavior. A novel scheme for feedback control of this device is presented, along with experimental results showing performance and safety of a one-link arm actuated by the VSA motor.
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paper_title: A new variable stiffness actuator (CompAct-VSA): Design and modelling

paper_content:

This paper describes the design and modelling of a new variable stiffness actuator (CompAct-VSA). The principle of operation of CompAct-VSA is based on a lever arm mechanism with a continuously regulated pivot point. The proposed concept allows for the development of an actuation unit with a wide range of stiffness and a fast stiffness regulation response. The implementation of the actuator makes use of a cam shaped lever arm with a variable pivot axis actuated by a rack and pinion transmission system. This realization results in a highly integrated and modular assembly. Size and weight are indeed an open issue in the VSAs design, which ultimately limit their implementation in multi-dof robotic systems. The paper introduces the mechanics, the principle of operation and the model of the actuator. Preliminary results are presented to demonstrate the fast stiffness regulation response and the wide range of stiffness achieved by the proposed CompAct-VSA design.
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paper_title: Design Approach of Biologically-Inspired Musculoskeletal Humanoids

paper_content:

In order to realize more natural and various motions like humans, humanlike musculoskeletal tendon-driven humanoids have been studied. Especially, it is very challenging to design musculoskeletal body structure which consists of complicated bones, redundant powerful and flexible muscles, and large number of distributed sensors. In addition, it is very challenging to reveal humanlike intelligence to manage these complicated musculoskeletal body structure. This paper sums up life-sized musculoskeletal humanoids Kenta, Kotaro, Kenzoh and Kenshiro which we have developed so far, and describes key technologies to develop and control these robots.
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paper_title: The cocktail party robot: sound source separation and localisation with an active binaural head

paper_content:

Human-robot communication is often faced with the difficult problem of interpreting ambiguous auditory data. For example, the acoustic signals perceived by a humanoid with its on-board microphones contain a mix of sounds such as speech, music, electronic devices, all in the presence of attenuation and reverberations. In this paper we propose a novel method, based on a generative probabilistic model and on active binaural hearing, allowing a robot to robustly perform sound-source separation and localization. We show how interaural spectral cues can be used within a constrained mixture model specifically designed to capture the richness of the data gathered with two microphones mounted onto a human-like artificial head. We describe in detail a novel EM algorithm, we analyse its initialization, speed of convergence and complexity, and we assess its performance with both simulated and real data.
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paper_title: Gain Scheduling Control for a Class of Variable Stiffness Actuators Based on Lever Mechanisms

paper_content:

This paper is concerned with the design of a control strategy for variable stiffness actuators in series configuration, exploiting the lever concept to adjust the stiffness at the transmission. A control strategy based on gain scheduling is proposed, which is able to regulate both stiffness and position at output link. The gain scheduling is designed based on a set of linear quadratic regulators (LQRs), because LQR's inherent robustness properties can accommodate significant variation in the actuation plant parameters. The link positioning relies on continuous adjustment of the control effort based on the current transmission stiffness; the stiffness perceived at the output link is regulated through combined action of the transmission stiffness and the positioning gains of the scheduling strategy. The effectiveness of the controller is verified in simulation and experiments on the actuator with adjustable stiffness. The overall strategy has been proven to be locally stable.
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paper_title: Anthrob - A printed anthropomimetic robot

paper_content:

Anthropomimetic robotics differ from conventional approaches by capitalizing on the replication of the inner structures of the human body, such as muscles, tendons, bones and joints [1]. Prominent examples for this class of robots are the robots developed at the JSK laboratory of the University of Tokyo and the robots developed by the EU-funded project Embodied Cognition in a Compliantly Engineered Robot (Eccerobot). However, the high complexity of these robots as well as their lack of sensors has so far failed to provide the desired new insights in the field of control. Therefore, we developed the simplified but sensorized robot Anthrob. The robot replicates the human upper limb and features 13 compliant tendon driven uni- and biarticular muscles as well as a spherical shoulder joint. Whenever possible, Selective Laser Sintering (SLS) was used for the production of the robot parts to reduce the production costs and to implement cutting-edge technologies, such as tendon canals or solid-state joints.
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paper_title: A scalable joint-space controller for musculoskeletal robots with spherical joints

paper_content:

In the long history of robotics research, the most prominent problem has always been, to develop robots that can safely operate in human-centered environments. One way towards the goal of a safe, and human-friendly robot, is to incorporate more and more of the flexibility that can be found in humans, by mimicking the internal mechanisms. In this work we propose a scalable joint-space control scheme based on computed torque control for an anthropomimetic robot. To achieve this, the dynamic system model of the robot is decomposed into hierarchical subsystems, using scalable modeling algorithms where possible. Machine learning techniques were employed to tackle the problem of muscle force to joint torque mapping. The developed control scheme has been evaluated using the highly refined simulation of an anthropomimetic robot arm featuring 11 muscles, a revolute elbow joint and a spherical shoulder joint. We show trajectory tracking based on a low-level muscle and a high-level joint control scheme, taking into account the coupling between the joints due to inertial reactions and bi-articular muscles.
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paper_title: Design and Realization of a Humanoid Robot for Fast and Autonomous Bipedal Locomotion

paper_content:

This thesis covers the mechatronic conception, design and realization of a humanoid walking robot. Weighing approximately 60 kg, the robot stands 180 cm tall and has 25 actuated degrees of freedom in a redundant configuration. The mechanical structure is characterized by the consistent lightweight design with high effective stiffness. The lightweight servo actuators combine high-dynamic brushless servo motors with precision gearings and sensors into a compact package. Moreover, the resultant inertia of the legs is minimized by a sophisticated design of the structure and drive mechanisms, resulting in a superior acceleration behavior. The sensor layout comprises angular sensors for direct measurement of the joint angles, a high-precision inertial measurement system and force/torque sensors in the feet. Using the trajectory generation and control system, which is not in the scope of this work, the current speed of locomotion is 3.34 km/h.
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paper_title: A six-axis force sensor with parallel support mechanism to measure the ground reaction force of humanoid robot

paper_content:

This paper describes a design of six-axis force sensor that measures ground reaction force of human or humanoid robot. The key concept is parallel support mechanisms, that allow large torques and forces which are caused when foot is hitting to the environment. Basic concept and design of parallel support mechanisms are denoted. Finally ground reaction force measurement system for human walking, and application to humanoid robot walking are described.
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paper_title: Humanoid HRP2-DHRC for Autonomous and Interactive Behavior

paper_content:

Recently, research on humanoid-type robots has become increasingly active, and a broad array of fundamental issues are under investigation. However, in order to achieve a humanoid robot which can operate in human environments, not only the fundamental components themselves, but also the successful integration of these components will be required. At present, almost all humanoid robots that have been developed have been designed for bipedal locomotion experiments. In order to satisfy the functional demands of locomotion as well as high-level behaviors, humanoid robots require good mechanical design, hardware, and software which can support the integration of tactile sensing, visual perception, and motor control. Autonomous behaviors are currently still very primitive for humanoid-type robots. It is difficult to conduct research on high-level autonomy and intelligence in humanoids due to the development and maintenance costs of the hardware. We believe low-level autonomous functions will be required in order to conduct research on higher-level autonomous behaviors for humanoids.
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paper_title: A whole-body control framework for humanoids operating in human environments

paper_content:

Tomorrow's humanoids will operate in human environments, where efficient manipulation and locomotion skills, and safe contact interactions are critical design factors. We report here our recent efforts into these issues, materialized into a whole-body control framework. This framework integrates task-oriented dynamic control and control prioritization allowing to control multiple task primitives while complying with physical and movement-related constraints. Prioritization establishes a hierarchy between control spaces, assigning top priority to constraint-handling tasks, while projecting operational tasks in the null space of the constraints, and controlling the posture within the residual redundancy. This hierarchy is directly integrated at the kinematic level, allowing the program to monitor behavior feasibility at runtime. In addition, prioritization allows us to characterize the dynamic behavior of the individual control primitives subject to the constraints, and to synthesize operational space controllers at multiple levels. To complete this framework, we have developed free-floating models of the humanoid and incorporate the associated dynamics and the effects of the resulting support contacts into the control hierarchy. As part of a long term collaboration with Honda, we are currently implementing this framework into the humanoid robot Asimo
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paper_title: A highly stretchable tactile distribution sensor for smooth surfaced humanoids

paper_content:

Stretchable tactile distribution sensors are significantly important in realizing natural and rich tactile interactions for next generation humanoids with soft and smooth surfaces. We have developed such a sensor which has no wiring in most of the sensing area and is based on inverse problem technique - EIT. At first, we show the ability of the sensor to detect novel and rich tactile interactions involving skin deformation such as pinching and rubbing. Furthermore, by using our newly developed conductive knitted fabric, we demonstrate how the sensor can be extremely useful for sensing pressure distributions as well as for covering complex 3D surfaces such as the face. Also, we show a successful implementation of the highly stretchable sensor over movable joints, the repeatability of the sensor value against joint movements and the detectability of external tactile stimuli for various joint angles are also demonstrated.
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paper_title: An embedded artificial skin for humanoid robots

paper_content:

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: Tactile Sensing—From Humans to Humanoids

paper_content:

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: Integrating discrete force cells into multi-modal artificial skin

paper_content:

In this paper, we present a new version of our multi-modal artificial skin, building from hexagonal shaped, intelligent unit cells. Our focus lies on the design of a discrete normal force sensor cell and its integration next to existing sensors for pre-contact, vibration/motion and temperature. The new force cell is cheap and easy to manufacture, scalable in size and force range, and addresses common drawbacks like hysteresis, noise, robustness and bandwidth. We locally sample and pre-process signals at 2.5 kHz and transfer filtered data at 250 Hz, enabling signal to noise ratios above 50 dB. Our rigid unit cells are encapsulated into 3D printed elastomer molds - we now mix hard and soft materials in the epidermal skin layer, in order to support enhanced force sensing. We provide detailed experimental characterization of the new force sensing modality on a custom dynamic test bench.
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paper_title: KinectFusion: Real-time dense surface mapping and tracking

paper_content:

We present a system for accurate real-time mapping of complex and arbitrary indoor scenes in variable lighting conditions, using only a moving low-cost depth camera and commodity graphics hardware. We fuse all of the depth data streamed from a Kinect sensor into a single global implicit surface model of the observed scene in real-time. The current sensor pose is simultaneously obtained by tracking the live depth frame relative to the global model using a coarse-to-fine iterative closest point (ICP) algorithm, which uses all of the observed depth data available. We demonstrate the advantages of tracking against the growing full surface model compared with frame-to-frame tracking, obtaining tracking and mapping results in constant time within room sized scenes with limited drift and high accuracy. We also show both qualitative and quantitative results relating to various aspects of our tracking and mapping system. Modelling of natural scenes, in real-time with only commodity sensor and GPU hardware, promises an exciting step forward in augmented reality (AR), in particular, it allows dense surfaces to be reconstructed in real-time, with a level of detail and robustness beyond any solution yet presented using passive computer vision.
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paper_title: VISION-BASED HUMANOID NAVIGATION USING SELF-SUPERVISED OBSTACLE DETECTION

paper_content:

In this paper, we present an efficient approach to obstacle detection for humanoid robots based on monocular images and sparse laser data. We particularly consider collision-free navigation with the Nao humanoid, which is the most popular small-size robot nowadays. Our approach first analyzes the scene around the robot by acquiring data from a laser range finder installed in the head. Then, it uses the knowledge about obstacles identified in the laser data to train visual classifiers based on color and texture information in a self-supervised way. While the robot is walking, it applies the learned classifiers to the camera images to decide which areas are traversable. As we show in the experiments, our technique allows for safe and efficient humanoid navigation in real-world environments, even in the case of robots equipped with low-end hardware such as the Nao, which has not been achieved before. Furthermore, we illustrate that our system is generally applicable and can also support the traversability estimation using other combinations of camera and depth data, e.g. from a Kinect-like sensor.
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paper_title: Continuous humanoid locomotion over uneven terrain using stereo fusion

paper_content:

For humanoid robots to fulfill their mobility potential they must demonstrate reliable and efficient locomotion over rugged and irregular terrain. In this paper we present the perception and planning algorithms which have allowed a humanoid robot to use only passive stereo imagery (as opposed to actuating a laser range sensor) to safely plan footsteps to continuously walk over rough and uneven surfaces without stopping. The perception system continuously integrates stereo imagery to build a consistent 3D model of the terrain which is then used by our footstep planner which reasons about obstacle avoidance, kinematic reachability and foot rotation through mixed-integer quadratic optimization to plan the required step positions. We illustrate that our stereo imagery fusion approach can measure the walking terrain with sufficient accuracy that it matches the quality of terrain estimates from LIDAR. To our knowledge this is the first such demonstration of the use of computer vision to carry out general purpose terrain estimation on a locomoting robot — and additionally to do so in continuous motion. A particular integration challenge was ensuring that these two computationally intensive systems operate with minimal latency (below 1 second) to allow re-planning while walking. The results of extensive experimentation and quantitative analysis are also presented. Our results indicate that a laser range sensor is not necessary to achieve locomotion in these challenging situations.
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paper_title: iSAM2: Incremental smoothing and mapping using the Bayes tree

paper_content:

We present a novel data structure, the Bayes tree, that provides an algorithmic foundation enabling a better understanding of existing graphical model inference algorithms and their connection to sparse matrix factorization methods. Similar to a clique tree, a Bayes tree encodes a factored probability density, but unlike the clique tree it is directed and maps more naturally to the square root information matrix of the simultaneous localization and mapping (SLAM) problem. In this paper, we highlight three insights provided by our new data structure. First, the Bayes tree provides a better understanding of the matrix factorization in terms of probability densities. Second, we show how the fairly abstract updates to a matrix factorization translate to a simple editing of the Bayes tree and its conditional densities. Third, we apply the Bayes tree to obtain a completely novel algorithm for sparse nonlinear incremental optimization, named iSAM2, which achieves improvements in efficiency through incremental variable re-ordering and fluid relinearization, eliminating the need for periodic batch steps. We analyze various properties of iSAM2 in detail, and show on a range of real and simulated datasets that our algorithm compares favorably with other recent mapping algorithms in both quality and efficiency.
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paper_title: Real-time super-resolution three-dimensional sound source localization for robots

paper_content:

This paper investigates Sound Source Localization (SSL) for a robot in a real world. Previously, we focused on one-dimensional SSL for azimuth and assumed that target sources are distributed close to a horizontal plane. Without this assumption, the SSL performance is drastically degraded. Thus, three-dimensional SSL is essential to improve the localization for sound sources distributed in a three-dimensional space. Compared to one-dimensional SSL, three-dimensional SSL mainly has the following problems: 1) a massive number of Transfer Function (TF) measurements for microphone array calibration are required for three dimensions to maintain the spatial resolution of SSL sufficiently-high, 2) the computational cost for searching for sound sources drastically increases in high-dimensional spaces. For the first issue, we extend the previously-proposed one-dimensional TF interpolation method, integrating time-domain-based and frequency-domain-based interpolation, to three dimensions. The interpolation achieves three-dimensional super-resolution SSL and reduction of the number of TF measurements while maintaining the spatial resolution of SSL. For the second issue, we propose optimal hierarchical SSL, which reduces computational cost for searching for sound sources by introducing a hierarchical search algorithm instead of using greedy search in localization. We previously proposed the concept of the algorithm. This paper additionally discusses theoretical optimality in hierarchization to minimize the total computational cost of SSL. The method determines the number of hierarchies and the resolution of each hierarchy depending on desired spatial resolution. These techniques are integrated into an SSL system using a robot. The experimental result showed: 1) the proposed interpolation method achieved super-resolution SSL working better than that with pre-measured TFs, 2) the optimal hierarchical SSL drastically reduced computational cost by approximately 97%.
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paper_title: Improvement in listening capability for humanoid robot HRP-2

paper_content:

This paper describes improvement of sound source separation for a simultaneous automatic speech recognition (ASR) system of a humanoid robot. A recognition error in the system is caused by a separation error and interferences of other sources. In separability, an original geometric source separation (GSS) is improved. Our GSS uses a measured robot's head related transfer function (HRTF) to estimate a separation matrix. As an original GSS uses a simulated HRTF calculated based on a distance between microphone and sound source, there is a large mismatch between the simulated and the measured transfer functions. The mismatch causes a severe degradation of recognition performance.
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paper_title: The cocktail party robot: sound source separation and localisation with an active binaural head

paper_content:

Human-robot communication is often faced with the difficult problem of interpreting ambiguous auditory data. For example, the acoustic signals perceived by a humanoid with its on-board microphones contain a mix of sounds such as speech, music, electronic devices, all in the presence of attenuation and reverberations. In this paper we propose a novel method, based on a generative probabilistic model and on active binaural hearing, allowing a robot to robustly perform sound-source separation and localization. We show how interaural spectral cues can be used within a constrained mixture model specifically designed to capture the richness of the data gathered with two microphones mounted onto a human-like artificial head. We describe in detail a novel EM algorithm, we analyse its initialization, speed of convergence and complexity, and we assess its performance with both simulated and real data.
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paper_title: Multi-talker speech recognition under ego-motion noise using Missing Feature Theory

paper_content:

This paper presents a system that gives a mobile robot the ability to recognize target speaker's speech, even if the robot performs an action and there are multiple speakers talking in the room. Associated problems to this system are twofold: (1) While the robot is moving, the joints inevitably generate ego-motion noise due to its motors. (2) Recognizing target speech against other interfering speech signals is a difficult task. Since typical solutions to (1) and (2), motor noise suppression and sound source separation, both introduce distortion to the processed signals, the performance of automatic speech recognition (ASR) deteriorates. Instead of removing the ego-motion noise with conventional noise suppression methods, in this work, we investigate methods to eliminate the unreliable parts of the audio features that are contaminated by the ego-motion noise. For this purpose, we model masks that filter unreliable speech features based on the ratio of speech and motor noise energies. We analyze the performance of the proposed technique under various test conditions by comparing it to the performance of existing Missing Feature Theory-based ASR implementations. Finally, we propose an integration framework for two different masks that are designed to eliminate ego noise and to filter the leakage energy of interfering sound sources. We demonstrate that the proposed methods achieve a high ASR accuracy.
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Title: An Overview of Humanoid Robots Technologies

Section 1: Mechanical structure
Description 1: Discuss the overall design principles and importance of mechanical structure, including size, weight, and strength of humanoid robots.

Section 2: Mass distribution
Description 2: Explain the role of mass distribution in maintaining robot balance and its impact on computational models and control mechanisms.

Section 3: Human robot interaction
Description 3: Describe the importance of force control for safety in human-robot interactions, and the use of sensors and compliant design to achieve this.

Section 4: Mechanical resonance
Description 4: Address the challenges related to mechanical resonance, its implications on robot performance, and ways to manage or utilize it.

Section 5: Estimating the leg deformation
Description 5: Explain the methods for evaluating link deformations and natural frequencies, focusing on beam theory application.

Section 6: Robot skeleton
Description 6: Outline the kinematic structure inspired by human anatomy and discuss variations in joint design for performance improvement.

Section 7: Grippers
Description 7: Discuss the design and application-specific selection of grippers, balancing dexterity and load capacity.

Section 8: Mobility
Description 8: Explore different mobility solutions for humanoid robots, including bipedal and mobile platform designs, and their respective advantages.

Section 9: Foot
Description 9: Examine the crucial role of feet in humanoid robots, including requirements for friction, impact handling, and sensor integration.

Section 10: Constraints from the environment
Description 10: Discuss environmental constraints (e.g., dust, humidity) and how they affect the design and operation of humanoid robots.

Section 11: Computational structure
Description 11: Outline the computational needs for humanoid robots, focusing on embedded computers and their capabilities.

Section 12: Communication buses
Description 12: Discuss the importance and requirements of communication buses in humanoid robots, including real-time constraints and robustness.

Section 13: Wireless communication
Description 13: Explain the role and challenges of wireless communication, including frequency considerations and interference from the environment.

Section 14: Middleware
Description 14: Provide an overview of middleware solutions for humanoid robots, focusing on frameworks that support data exchange and real-time processing.

Section 15: Actuators
Description 15: Describe various actuator technologies used in humanoid robots, including electric, hydraulic, and pneumatic actuators, and their specific advantages.

Section 16: Encoders
Description 16: Detail the importance of encoders for precision in joint movement and methods for measuring joint positions.

Section 17: Force torque sensors
Description 17: Discuss the role of force-torque sensors in maintaining balance and measuring interactions with the environment.

Section 18: Joint level torque sensors
Description 18: Explain the utility of joint-level torque sensors for control laws and inverse dynamics implementation.

Section 19: Accelerometers and gyrometers
Description 19: Outline the use of IMUs to measure orientation and motion, and their integration with other sensors for enhanced accuracy.

Section 20: Artificial skins
Description 20: Explore the development and application of artificial skins in humanoid robots for detecting forces and contact points.

Section 21: Vision - Lidar
Description 21: Discuss the importance of visual and Lidar systems for environment mapping, footstep planning, and object interaction.

Section 22: Audition
Description 22: Examine the use of microphones for human-robot interaction, focusing on source localization and separation techniques.

Section 23: Conclusion
Description 23: Summarize the technological advancements in humanoid robots, potential applications, and remaining challenges.