Publisher：Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS  

With advancing technology, human assistive robots have been developed to enhance daily efficiency for users. Focusing on the reaching motions of the upper limb, this study aims to propose a motion classification method based on electromyographic (EMG) signals that can accurately and promptly differentiate among three distinct types of reaching motion - regular reaching, extended reaching, and weighted reaching - regardless of the motion direction. In the proposed method, the EMG signals of upper limb and torso muscles relevant to these reaching motions are used to identify pivotal features capable of clearly classifying these different reaching motions. A Gated Recurrent Unit (GRU) network is employed to train the model and infer user intentions based on the signal features. The results confirmed the efficiency in motion classification, which laid the foundation for the future application of human assist robots, enabling them to provide users with timely and precise responses.

DOI： 10.1109/EMBC53108.2024.10782746

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE-RAS International Conference on Humanoid Robots  

Using robots as badminton training partners, the robots preferred to be humanoid in shape. However, existing humanoid robots lack the tipping stability required to perform badminton footwork. In this research, to improve the tipping stability of humanoid robots, we proposed to install adsorption mechanisms on the sole. The robot with three degrees of freedom (DOFs) on one leg was developed as a preliminary step for the evaluation of the mechanisms. First, the basic characteristics of the adsorption mechanisms were evaluated. The evaluation showed that the tipping stability of the robot was improved. In addition, three motions were performed with the developed robot: maintaining a standing posture, stepping forward, and stepping backward. These motions were realized by using a combination of feedforward control and proportional-integral-differential (PID) control. In the forward stepping motion, the robot achieved a quick approach speed of 1.56 m/s. Also, the estimation of the zero moment point (ZMP) during the motion showed that the robot could be prevented from tipping by the adsorption mechanisms.

DOI： 10.1109/Humanoids57100.2023.10375201

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Other Link： https://dblp.uni-trier.de/db/conf/humanoids/humanoids2023.html#YoshidaKN23

Repository Public URL： https://hdl.handle.net/2324/7178574

Language：Others   Publishing type：Research paper (other academic)   Publisher：Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics  

Artificial motion sensation can be used for virtual reality, rehabilitation, etc. It is known that joint motion illusion is induced by giving certain vibration stimulation on human muscles even though the joint is not actually moved. In this paper, a method to generate motion illusion of arbitrary hand reaching motion, which is one of the most important daily living movements, by giving multiple vibration stimulations on shoulder and elbow muscles is proposed. In order to generate hand reaching motion illusion, frequency of vibration stimulation is controlled on each muscle at the same time considering the spatial hand movement in the proposed method. The experimental of generating hand reaching motion illusion is carried out to evaluate the effectiveness of the proposed method.

DOI： 10.1109/SMC53992.2023.10394114

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Other Link： https://dblp.uni-trier.de/db/conf/smc/smc2023.html#AbeNK23

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics  

Engineering support for sports has the potential to improve training performance. Most research on sports training support has focused on support in areas that directly affect the point of force action. On the other hand, even if sports with hand-held tools, the importance of lower body motor function has been indicated. This suggests that supporting areas away from the point of force action can improve the performance of novice players. Therefore, in this study, we developed an assist suit that facilitates lower body twisting for table tennis beginners during forehand swing. U sing this assistive suit, experiments were conducted for the experimental group under the following four conditions (1) 'No wear (before),' (2) 'Without assist,' (3) 'With assist,' and (4) 'No wear (after)' to clarify the effect of wearing, assist, and training. In addition, a control group in which participants hit the ball without the assist suit was set up to examine the training effect of repetition. The results showed that both the amount of waist rotation and racket velocity increased significantly in the experimental group compared to the control group, which indicates the effect of the assist suit on training.

DOI： 10.1109/SMC53992.2023.10393870

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Other Link： https://dblp.uni-trier.de/db/conf/smc/smc2023.html#KashiwagiKN23

Repository Public URL： https://hdl.handle.net/2324/7178580

Language：Others   Publishing type：Research paper (scientific journal)   Publisher：IEEE Access  

Robotic prosthetic hands can help perform the intended sophisticated movements of the upper limb, which can assist amputees to perform their daily activities. Although a robotic prosthetic hand can be controlled in real-time using the user's electromyography (EMG), which directly reflects the user's motion intention, some important EMG signals are usually lost owing to muscle deficiency. This study proposes a muscle activity estimator that is inspired by the muscle synergy across subjects to estimate the activity of the missing muscles in amputees in real-time. The proposed estimator learns muscle synergy from the EMG balance, finger joint angles, and the grasping force of healthy persons. The proposed estimator is developed as an artificial neural network (ANN) with a novel cell structure that combines long-short-term memory and damping neurons to analyze muscle dynamics. Furthermore, to improve the accuracy of learning muscle synergy, the muscles to be input to the estimator are selected by focusing on the enslavement of muscles and anatomical relationships. The effectiveness of the proposed estimator is evaluated by experiments. The results showed that the proposed estimator can contribute well to the realization of the intended sophisticated motions of the user.

DOI： 10.1109/ACCESS.2023.3312575

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Language：Others   Publishing type：Research paper (other academic)   Publisher：2023 IEEE/SICE International Symposium on System Integration, SII 2023  

In recent years, research and development of human assist robots have been actively carried out in order to support the independent lives of persons with impaired motor function. Although assisting the user's activity according to the user's motion intention is important for the human assist robots, it is difficult to objectively determine in real time whether the assisted motion by the robot is exactly same as the intended motion by the user. In this paper, a method to objectively detect a user's sense of assist mismatch using EEG signals is investigated. Experiments were conducted to analyze the user's brain activities during the ankle joint movement with the assist of intended and unintended motion. The experimental results show that there are differences in the theta wave activities around the central area of the head and alpha wave activities around the central sulcus when assist mismatch occurs. These results suggest that a user's sense of mismatch can be detected with the proposed method.

DOI： 10.1109/SII55687.2023.10039324

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Other Link： https://dblp.uni-trier.de/db/conf/sii/sii2023.html#KiguchiYN23

Language：Others   Publishing type：Research paper (other academic)   Publisher：2023 IEEE/SICE International Symposium on System Integration, SII 2023  

It is known that vibratory stimulation of muscle tendons induces kinesthetic illusions, tonic vibration reflex (TVR) and antagonist vibratory response (AVR). In order to utilize kinesthetic illusion, TVR, and AVR in a wide range of fields, it is necessary to investigate the characteristics of the three phenomena in various joints. In particular, the shoulder joint plays an important role in upper limb motion, and vibration stimulation characteristics in the shoulder joint extension direction have not yet been quantitatively evaluated. In this study, by applying vibration stimulation to the tendon of origin in biceps brachii long head and tendon of insertion in biceps brachii muscle, a multi-articular muscle, the amount of kinesthetic illusion, TVR and AVR in the shoulder joint extension direction are compared in each frequency. The experimental results shows that the kinesthetic illusion is generated not only in the tendon of origin but also in the tendon of insertion by the vibration stimulus. Also, the stimulation to the tendon of origin induces TVR at 100-120 Hz, but the vibration stimulation to the tendon of insertion does not at any used frequency range. Finally, it was found that vibratory stimulation to the tendon of insertion produced more AVR than vibratory stimulation to the tendon of origin. The results of this study provide the necessary knowledge to control artificial sensation and motion compensation in the shoulder joint extension direction.

DOI： 10.1109/SII55687.2023.10039145

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Other Link： https://dblp.uni-trier.de/db/conf/sii/sii2023.html#TeranishiNK23

Language：Japanese   Publisher：バイオメカニズム学会  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Sports Biomechanics  

In pole vaulting, model analysis is one of the key methods to increase vaulting height. To date, the effects of athletes' motions during 'pole support phase' have been measured and modelled to improve and set new world records. The motions were extracted based on the context of pole bending interaction and parameters to improve vaulting height were investigated. However, due to experimental, mechanical, and sensing restrictions, ranges and interactions of the parameters were poorly addressed. To investigate further, a parameter space must be globally explored. Here, we show parameter sensitivities and interactive effects between initial velocity, pole length, bending amplitude and switching time. From the simulation studies, we found that active pole bending enabled successful pole vaulting with lower initial velocity and longer poles. Vaulting height had a local maximum point at a specific initial velocity and positive bending could control conditions to deliver the local maximum height. Positive bending controls the rising-up speed of the pole and contributes to the verticalisation of the vaulting angle. Negative bending increases the vaulting speed and contributes to the robustness of the vaulting angle. Our results demonstrate how these parameters affect the vaulting performances and suggest how athletes should activate their bodies.

DOI： 10.1080/14763141.2022.2129087

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：International Conference on Sport Sciences Research and Technology Support, icSPORTS - Proceedings  

Movement form is important in sports. However, self-learning of the form has a possibility that people will acquire a form which puts a burden on one part of the body or a form which cannot exert sufficient power. Although there is also a way to have an instructor, people do not always receive the instruction of the form. Therefore, it is useful for sports training to develop a device which allows participants to acquire a form suited for each sport. Existing research about support in sports with a racket does not pay much attention to the lower body. In this research, we developed an assist suit that assists the lower body in executing a forehand swing in table tennis with lower-body twisting. Using this suit for beginners of table tennis, we conducted experiments under four conditions:(1) "No wear (before)", (2) "Without assist", (3) "With assist", and (4) "No wear (after)". As a result of Tukey analysis within each participant, the range of movement of the lower body is statistically increased by the assist suit and there are individual differences in whether to acquire a swing with twisting the lower body.

DOI： 10.5220/0011557000003321

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Other Link： https://dblp.uni-trier.de/db/conf/icsports/icsports2022.html#KashiwagiNNK22

Repository Public URL： https://hdl.handle.net/2324/7178577

Language：Others   Publishing type：Research paper (other academic)   Publisher：World Automation Congress Proceedings  

The artificial sensation of walking can be applied to enhancing the self-efficacy and self-agency of persons whose motions are assisted by human assist-robots. When mechanical vibratory stimulation is applied to muscle tendons, a phenomenon called "Kinesthetic Illusion (KI)"is induced. The stimulated muscle feels as if it is being extended, even though it is not moving when KI is induced. If this phenomenon can be generated and controlled at the ankle joint, an artificial gait sensation can be generated. It is known that a variety of muscles such as Gastrocnemius (GA), Tibialis Anterior (TA), Peroneus Longus (PL), and Tibialis Posterior (TP) act on gait. Therefore, it would be possible to enhance gait sensation and generate two-dimensional gait sensations, such as in the sagittal and anterior forehead planes if KI is generated for those muscles. This paper investigates a basic study of KI characteristics in the two-dimensional direction at GA, TA, PL, and TP. The experiment results revealed the possibility of KI generation in the two-dimensional direction. Moreover, it is found that vibration stimulation at 30Hz-40Hz is adequate for generating KI in all muscles. The results of this study demonstrate the possibility of generating a two-dimensional gait sensation.

DOI： 10.23919/WAC55640.2022.9934478

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Other Link： https://dblp.uni-trier.de/db/conf/wac2/wac2022.html#YamasakiNK22

Language：Others   Publishing type：Research paper (other academic)   Publisher：Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics  

Human-assist robots are designed to reduce the burden on the body when lifting objects and assist the elderly, disabled, and other people with muscle weakness in their daily activities. They also avoid accidents and assist motions by recognizing what kind of motion the user is about to make. Therefore, human-assist systems need to estimate the motion intention of a user in real time. The sooner the assist robot can accurately recognize the user's motion, the sooner the assist robot can plan which motion to assist and how to assist it to guarantee success. If the user's intended motion and its phase are estimated in the early stage of the motion, the assist robot can Figure out how the user is moving by comparing with standard motion models to assist the motion as necessary. This paper proposes a method to estimate the user's intended motion and its phase simultaneously in real time based on integrated information consisting of the user's posture, motion, EMG signals, and the surrounding environment. Two kinds of artificial neural networks are applied in the proposed method. Damping neurons are used in the artificial neural network to estimate the motion phase effectively. The intended lower-limb motions and their phases in daily living motion are estimated in real-time. The effectiveness of the proposed method was evaluated by performing experiments of lower-limb motion.

DOI： 10.1109/SMC53654.2022.9945330

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE International Conference on Intelligent Robots and Systems  

For universal robotic limbs, having a large workspace with high stiffness and adjustable output properties is important to adapt to various situations. A combination of parallel mechanisms that can change output characteristics is promising to meet these demands. As such, we propose a lever mechanism with double parallel link platforms. This mechanism is composed of a lever mechanism with the effort point and the pivot point; each is supported by a parallel link mechanism. First, we calculated the differential kinematics of this mechanism. Next, we investigated the workspace of the mechanism. The proposed mechanism can reach nearer positions than the posture with the most shrinking actuators thanks to the three-dimensional movable effort point. Then, we confirmed that this mechanism could change the output force profile at the end-effector by changing the lever ratio. The main change is the directional change of the maximum output force. The change range is larger when the squatting depth is larger. The changing tendency of the shape of the maximum output force profile by the position of the pivot plate depends on the force balance of the actuators. These analytical results show the potential of the proposed mechanism and would aid in the design of this mechanism for robotic limbs.

DOI： 10.1109/IROS47612.2022.9981521

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Repository Public URL： https://hdl.handle.net/2324/7178581

Language：English   Publishing type：Research paper (other academic)  

Motor power distribution mechanism for simultaneous independent control of multiple cable tensions for humanoid robot hand

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE International Conference on Rehabilitation Robotics  

Artificially controlled kinesthesia can be applied to many situations because kinesthesia is essential to recognizing body movements. It could be used to generate artificial kinesthesia in rehabilitation or daily motion assist to improve self-efficacy of the robot user. Moreover, the controlled artificial kinesthesia could make people feel as if they are performing the actions of the robotic limbs with their own limbs. Mechanical vibration stimulation is one of the candidates to artificially control kinesthesia. It is known that mechanical vibration stimulation on human muscles or tendons from skin surface evokes an illusion of movement as if the stimulated muscles are extended. That effect of artificial kinesthesia is called Kinesthetic Illusion (KI). In this paper, a method to increase the amount of KI without changing the frequency of the vibration stimulation is investigated by applying mechanical skin stretch stimulation at the same time with the mechanical vibration stimulation. The experiment was conducted by generating KI for flexion motion of the elbow joint on a horizontal plane to evaluate the proposed approach. In the experiments, three out of five subjects showed obvious increase in the amount of KI when skin stretch stimulation was applied at the same time with the mechanical vibration stimulation. The results of this study provide a first step toward artificial kinesthesia control using a wearable robotic device using the mechanical vibration stimulation.

DOI： 10.1109/ICORR55369.2022.9896609

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Other Link： https://dblp.uni-trier.de/db/conf/icorr/icorr2022.html#MaemuraNK22

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>Typical sports support methods have a possibility that people will acquire a form which puts a burden on one part of the body or a form which cannot exert sufficient power and a problem that an instructor who gives guidance is essential. Therefore, it is necessary to develop a device which allow one person to acquire a form which could exert sufficient power. In this research, we developed an assist suit that assists the lower body during a forehand swing of table tennis for acquiring a forehand swing with twist of the lower body. And we conducted experiments using this suit for beginners of table tennis. As a result, the range of movement of the lower body increased by the assist suit and there are individual differences in whether to acquire a swing with twisting the lower body.</p>

DOI： 10.1299/jsmermd.2022.1a1-q07

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Language：English   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (other academic)  

It has been shown that changes in movement caused by reflex phenomena and kinesthetic illusion can be induced by giving vibratory stimulation on specific muscles during limb movements. By using this phenomenon, there is a possibility that the lower-limb perception-assist, in which inappropriate motion is automatically modified, is realized. In this study, change of ankle joint motion by giving the vibration stimulation on the gastrocnemius muscle in the lower-limb is studied by performing the experiment of adding vibration stimulation to the gastrocnemius muscle during the movement of ankle joint dorsiflexion and plantar flexion under several frequency ranges. The results indicate that the amount of motion change varies depending on the frequency of the vibration stimulation. Based on the characteristics of motion change with respect to vibration stimulation, a method to control the change of the user's ankle joint dorsiflexion motion by adjusting the frequency of the vibration stimulation to achieve the target motion, which is different from the user's intended motion, is evaluated. It is confirmed that there is a possibility that the vibration stimulation can be applicable to modify the human ankle joint motion for the perception-assist using frequency change.

DOI： 10.23919/ICCAS52745.2021.9649798

Language：Others   Publishing type：Research paper (scientific journal)  

The need for cable connection with soft robotic systems suppresses the benefits granted by their softness and flexibility. Such systems can be untethered by equipping batteries or by relying on non-electrical actuation mechanisms. However, these approaches cannot simultaneously support long-term and intelligent operations. This research examines a proposed wireless soft actuator based on wireless power transfer (WPT) and dielectric elastomer actuator (DEA) technology, thereby realizing soft robots more diversified application and long-term locomotion. A compact conical DEA fabrication process is presented with 6~mm periodic linear output and design of a lightweight WPT receiver that weighs only 13 g integrated with a driver circuit. Evaluation results show that this system remotely powers the DEA and the intelligent peripheral circuits for system control. Furthermore, our design bridges the WPT system seamlessly. It is power-efficient in low-voltage output conditions. The DEA, which requires high-voltage input (kV) for deformation, leverages high-voltage boost-converters. Experimentally obtained results demonstrate untethered DEA operation at 170 mm from the transmitter. Also, an untethered DEA application to a pump is assessed.

DOI： 10.1109/LRA.2021.3097271

Language：Others   Publishing type：Research paper (other academic)  

The physical human-robot interaction (pHRI) research field is expected to contribute to competitive and cooperative human-robot tasks that involve force interactions. However, compared with human-human interactions, current pHRI approaches lack tactical considerations. Current approaches do not estimate intentions from human behavior and do not select policies that are appropriate for the opponent's changing policy. For this reason, we propose a reinforcement learning model that estimates the opponent's changing policy using time-series observations and expresses the agent's policy in a common latent space, referring to descriptions of tactics in open-skill sports. We verify the performance of the reinforcement learning agent using two novel physical and competitive environments, push-hand game and air-hockey. From this, we confirm that the latent space works properly for policy information because each latent variable that represents the machine agent's own policy and that of the opponent affects the behavior of the agent. Two latent variables can clearly express how the agent estimates the opponent's policy and decides its own policy.

DOI： 10.1109/RO-MAN50785.2021.9515411

Language：English  

DOI： 10.1007/978-3-030-73113-7_24

Language：Others   Publishing type：Research paper (other academic)  

DOI： 10.1162/isal_a_00426

Language：Others   Publishing type：Research paper (other academic)  

We propose ThermoCaress, a haptic device to create a stroking sensation on the forearm using pressure force and present thermal feedback simultaneously. In our method, based on the phenomenon of thermal referral, by overlapping a stroke of pressure force, users feel as if the thermal stimulation moves although the position of temperature source is static. We designed the device to be compact and soft, using microblowers and infatable pouches for presenting pressure force and water for presenting thermal feedback. Our user study showed that the device succeeded in generating thermal referrals and creating a moving thermal illusion. The results also suggested that cold temperature enhance the pleasantness of stroking. Our fndings contribute to expanding the potential of thermal haptic devices.

DOI： 10.1145/3411764.3445777

Language：Others   Publishing type：Research paper (scientific journal)  

This paper focuses on the jump-and-hit motion of a humanoid robot, wherein a robot instantaneously jumps forward and hits a flying ball in the air, similar to how human players behave in volleyball games. We propose a novel immediate motion generation method that uses a lookup table of learned dynamics (IMoLo) for generating the motions of a pneumatic humanoid robot. To test this method, we developed a humanoid robot called &#x2018;`Liberobot&#x2019;' with eight joints applying structure-integrated pneumatic cable cylinders. Using simulations, the prediction errors of the robot hand positions during the jump-and-hit motions measured via nonlinear interpolation when using IMoLo was smaller than without it in cases having a small number of training trials. In the experiments, the robot jumped and hit the flying ball 16~times out of 20~trials using the proposed motion generation method. The results indicate that a pneumatic humanoid robot using IMoLo can instantaneously perform dynamic whole-body motions, such as jump-and-hit motions, with a changing target within a specified time. Our humanoid robot is the first pneumatic humanoid robot capable of executing such dynamic motions.

DOI： 10.1109/LRA.2021.3076959

Language：Others   Publishing type：Research paper (other academic)  

Soft robots have more passive degrees of freedom (DoFs) than rigid-body robots, which makes controller design difficult. Model-free reinforcement learning (RL) is a promising tool to resolve control problems in soft robotics alongside detailed and elaborate modeling. However, the adaptation of RL to soft robots requires consideration of the unique nature of soft bodies. In this work, a continuum robot arm is used as an example of a soft robot, and we propose an Ensembled Light-weight model-Free reinforcement learning Network (ELFNet), which is an RL framework with a computationally light ensemble. We demonstrated that the proposed system could learn control policies for a continuum robot arm to reach target positions using its tip not only in simulations but also in the real world. We used a pneumatically controlled continuum robot arm that operates with nine flexible rubber artificial muscles. Each artificial muscle can be controlled independently by pressure control valves, demonstrating that the policy can be learned using a real robot alone. We found that our method is more suitable for compliant robots than other RL methods because the sample efficiency is better than that of the other methods, and there is a significant difference in the performance when the number of passive DoFs is large. This study is expected to lead to the development of model-free RL in future soft robot control.

DOI： 10.1109/RoboSoft51838.2021.9479340

Language：English   Publishing type：Research paper (other academic)  

It is essential for a monitoring system or a communication robot that interacts with an elderly person to accurately understand the user's state and generate actions based on their condition. To ensure elderly welfare, quality of life (QOL) is a useful indicator for determining human physical suffering and mental and social activities in a comprehensive manner. In this study, we hypothesize that visual information is useful for extracting high-dimensional information on QOL from data collected by an agent while interacting with a person. We propose a QOL estimation method to integrate facial expressions, head fluctuations, and eye movements that can be extracted as visual information during the interaction with the communication agent. Our goal is to implement a multiple feature vectors learning estimator that incorporates convolutional 3D to learn spatiotemporal features. However, there is no database required for QOL estimation. Therefore, we implement a free communication agent and construct our database based on information collected through interpersonal experiments using the agent. To verify the proposed method, we focus on the estimation of the mental health QOL scale, which is the most difficult to estimate among the eight scales that compose QOL based on a previous study. We compare the four estimation accuracies: single-modal learning using each of the three features, i.e., facial expressions, head fluctuations, and eye movements and multiple feature vectors learning integrating all the three features. The experimental results show that multiple feature vectors learning has fewer estimation errors than all the other single-modal learning, which uses each feature separately. The experimental results for evaluating the difference between the estimated QOL score by the proposed method and the actual QOL score calculated by the conventional method also show that the average error is less than 10 points and, thus, the proposed system can estimate the QOL score. Thus, it is clear that the proposed new approach for estimating human conditions can improve the quality of human-robot interactions and personalized monitoring.

DOI： 10.1109/RO-MAN47096.2020.9223606

Language：Others   Publishing type：Research paper (other academic)  

Table-tennis robots struggle to return a spinning ball to the opponent' s court because the direction of bound depends on the direction and magnitude of the spin. We aim to solve this problem using a swing motion that is robust over a large range of spin patterns without accurate recognition of the spin. Specifically, we examine the relation between the swing speed and direction of return. When the racket speed is 7 m/s, the difference in the return direction is only 20 &#37; of that when the racket is not swung for the ball spinning in the range from -20 to 20 rev/s. In addition, we investigate the increase in swing speed of the racket due to flexibility of the swinging arm. We find that a flexible arm swings more rapidly than a rigid arm throughout the range of motion when exploiting the joint angle limit.

DOI： 10.1109/MHS48134.2019.9249276

Language：Others   Publishing type：Research paper (other academic)  

For immediate motion, taking a ready posture is a promising way because it can reduce enormous possible patterns of movement. For the selection of an appropriate ready posture, it is essential to know the structure of the task that includes the physical characteristics of a robot. We investigated our previous-built badminton robot arm to decide an appropriate ready posture as a case study. We first examined the kinematic characteristics to extract possible ready postures. In this analysis, we found that postures for hitting shuttles are limited to approximately one-tenth of all possible postures. Besides, these postures could be spatially divided into two clusters, one is for forehand shots, and the other is for backhand shots. Then, we calculated reaching time from various postures and confirmed that possible ready postures by kinematics analysis shortened averaged reaching time. We also found that there are more effective ready postures if considering the dynamics of the robot. These ready postures did not resemble those calculated by kinematics analysis.

DOI： 10.1109/ROBIO49542.2019.8961788

Language：English   Publishing type：Research paper (scientific journal)  

In this study, we present a length sensor that can be used for extensible soft pneumatic actuators. Conventional length sensors detect the changes in electrical resistance and capacitance owing to the deformation of the actuator; hence, deterioration and destruction occur when they are used with an actuator that has a large expansion ratio. In addition, their low resolution and linearity makes them unsuitable for use in actuator control. Our proposed sensor comprises only a speaker and a microphone installed at one end of the actuator. We propose a method to deterministically measure the length of a tube by generating a broadband acoustic signal in a tube and measuring the resonance characteristics determined by the shape of the tube. Our experimental results demonstrate that the error in the measurement with our sensor is not more than 4% with a strain up to 200%. Unlike conventional acoustic sensing methods that measure the time of flight by using ultrasound, our proposed method yields accurate results even when the tube is bent. Therefore, the proposed method can be applied to various types of pneumatic actuators.

DOI： 10.1109/LRA.2019.2931273

Language：Others   Publishing type：Research paper (scientific journal)  

We describe the development of a robot configured to play badminton, a dynamic sport that requires high accuracy. We used pneumatic-electric hybrid actuators, each combining a pneumatic actuator, with high-speed and lightweight attributes, and an electric motor with good controllability. Our first objective was to develop hybrid actuators that are lightweight and compact and with integrated sections. Using parts made of lightweight materials such as plastics and aluminum coils, and using wire for power transmission, we made actuators much lighter and smaller than previous ones. In addition, for high accuracy and power, tension sensor units and a heat countermeasure mechanism were also incorporated. As practice partners, we consider badminton robots to be more useful if they were humanoid in appearance and have a variety of shots. We, therefore, developed a humanoid robot arm. By incorporating actuators as link structures, the overall weight was reduced, and both complex degrees of freedom (DoFs) and a large range of motion were realized. Subsequently, we developed a robot with seven DoFs, three DoFs for the shoulder, two for the elbow, and two for the wrist, similar to the configuration of human arms. The robot, therefore, roughly reproduces human movements. At 19 m/s, the maximum speed of the racket was quite fast. The hybrid control reduced the motion variance, allowing improvements in accuracy of more than three times that of motions with only pneumatic control. In addition, performing path planning and tracking control with high precision was possible, tasks that are difficult for conventional pneumatic dynamic robots.

DOI： 10.1109/LRA.2019.2928778

Language：English   Publishing type：Research paper (other academic)  

CONTROL OF PNEUMATIC CYLINDERS USING ITERATIVE LINEAR QUADRATIC REGULATOR WITH DEEP LOCAL LINEAR DYNAMICS FOR EXPLOSIVE MOTIONS

Language：English   Publishing type：Research paper (other academic)  

DOI： 10.13180/clawar.2019.26-28.08.12

Language：English   Publishing type：Research paper (international conference proceedings)  

For utilizing optogenetics in neuroscience research, a proper setup is necessary, which delivers sufficient light to target cells and minimizes unexpected side effects caused by light exposure. In this study, we were interested in the area of influence of optical surface stimulation on a spinal cord tissue. We built a 3D spinal cord structure of rat and utilized the Monte-Carlo methods to simulate the light transport in it. We first evaluated light propagation in homogeneous nervous tissue models. For a 10-mW, 470-nm light source, light intensity of 1 mW=mm was detected at depths of 1:14 and 1:77 mm in white and grey matter, respectively. This indicated a narrower spreading pattern of light in the white matter than in the grey matter. Since the grey matter, which contains the somatosensory pathways, is an important target of spinal cord stimulation, we focused on investigating how much light could reach this area in a multi-layered structure. The results showed that when an optical fiber was positioned in the center line of the spinal cord dorsal surface, most of the light energy was absorbed before reaching the grey matter. In contrast, when we put the fiber on a lateral position, 0:8mm away from the central line, relatively sufficient light intensity could be detected deep into the lamina 5 area. The experimental results obtained herein suggest that tissue type and the position of stimulation could greatly affect the area of influence of light stimulation in a 3D spinal cord. It is important to consider the location of the interested neural pathways and plan a proper stimulation site before conducting optogenetic surface stimulation of the spinal cord. 2

DOI： 10.1109/EMBC.2019.8856874

Language：Others   Publishing type：Research paper (other academic)  

The dolphin kick is a swimming style characterized by undulation of the body. As a platform for swimming research, we have developed a musculoskeletal humanoid robot called Triton. Triton has a flexible spine with erector spinae muscles and a stiffness adjustment system for lumbar joints. The musculoskeletal body includes biarticular and polyarticular muscles, providing multi-joint coordination. The robot is actuated by pneumatic muscles, yielding lightweight and inherently waterproof properties. The compliance of the joints allows interactions between body and fluid similar to those of human swimming. This study presents the design concept of Triton and experimental results from a water tank test. We compare the results with simulation and human movements reported in literature. The results show that the musculoskeletal swimming robot has similar cycle trends in joint angle and thrust force.

DOI： 10.1109/IROS.2018.8593912

Language：English   Publishing type：Research paper (other academic)  

We propose an extensible pneumatic continuum arm that elongates to perform reaching movements and object grasping, and is suspended on the ceiling to prevent interference with human workers in a desktop workspace. The selected actuators with bellows aim to enhance the arm motion capabilities. A single actuator can provide a maximum tension force of 150 N, and the proposed arm has a three-segment structure with a bundle of three actuators per segment. We measured the three-dimensional motion at the arm tip by using an optical motion-capture system. The corresponding results show that the arm can grasp objects with approximate radius of 80 mm and reach any point on the desktop. Furthermore, the maximum elongation ratio is 180%, with length varying between 0.75 m and 2.1 m. Experiments verified that the arm can grasp objects of various sizes and shapes. Moreover, we demonstrate the vertical transportation of objects taking advantage of the arm extensibility. We expect to apply the proposed arm for tasks such as grasping objects, illuminating desktops, and physically interacting with users.

DOI： 10.1109/ROBOSOFT.2018.8404919

Language：English   Publishing type：Research paper (other academic)  

Combination of various dynamic motions may lead to better performance of dynamic motion tasks by utilizing the energy transfer between the motions. We have developed a robot capable of doing sequential jumping-stepping motion for agile locomotion. The robot is a musculoskeletal humanoid robot that mimics human skeletal system and muscular system with pneumatic artificial muscles as the actuators. For realizing the motion, we decide muscle control command for each motion referring to the muscle activation pattern of a human. We have conducted experiments for the sequential jumping-stepping motion with our motion strategy on the developed musculoskeletal robot. The results show that the musculoskeletal robot performs faster stepping by performing pre-jumping before a stepping than stepping without pre-jumping. We have also found that proper timing of landing command became crucial for the stepping motion performance.

DOI： 10.1109/ROBIO.2018.8664787

Language：English   Publishing type：Research paper (scientific journal)  

Sports, especially badminton, require participants to perform dynamic and skillful motions. Previous robots have had difficulty in performing like a human because of their severe limitations of low operating speed, heavy bodies, and simplistic mechanisms. In this letter, we propose a new robot design that consists of a structure integrated with pneumatic actuators and noninterfering many-degree-of-freedom joints, for the realization of a high-speed and lightweight humanoid robot. We made a four-degree-of-freedom robot arm for badminton, which is an especially dynamic sport, aiming for maximum speed while meeting geometric requirements. The robot swung with a racket-head speed of 21 m/s, which is a value higher than speeds achieved by previous robotic arms. The robot also realized a skillful shot, namely the spin net shot, which cannot be performed by previous badminton robots having simple mechanisms. A pneumatic robot is considered difficult to control, especially in terms of feedback control. We found that the reproducibility of the robot was as fine as 10-40 mm at the racket head for four kinds of strong swings. Using feedforward control, we also conducted an experiment in which the robot hits a flying shuttle, and achieved a high hitting rate of 69.7% for powerful swings. We believe that this research expands the possibilities of the pneumatic robot and is the first step toward developing a skillful humanoid badminton robot.

DOI： 10.1109/LRA.2018.2803207

Language：English   Publishing type：Research paper (scientific journal)  

It is difficult to design agile soft-bodied robots owing to their inherent softness. To overcome this problem, we propose a structure-integrated bistable module that uses snap-through buckling for agile motions. First, we confirmed that a 0.05-m-long module was able to jump to 0.13 m high. Through investigation, we found a range of command parameters within which the module jumps consistently. Moreover, we showed that jumping performance had strong relation to the bending amplitude. Next, we induced a robot with two serially connected modules to roll forward and jump over an obstacle. In rolling, the robot became round for quick locomotion. In jumping, we found that buckling in one module induced buckling in the other module. The difference in buckling time between the two modules was shortened from the order of 0.1 s to the order of 0.01 s. This might be effective for error correction or useful for coordinated motions. These results show the effectiveness of the proposed structure-integrated bistable modules for making agile soft-bodied robots, and suggest ways of exploiting them.

DOI： 10.1109/LRA.2018.2794617

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.12792/jiiae.6.92

Language：English   Publishing type：Research paper (other academic)  

Musculoskeletal robots have several advantages in physical interactions. However, a method of teaching motion with physical interaction to a robot without the robot's model remains unavailable. Thus, we propose a bilateral teleoperation system for control of a musculoskeletal robot in this paper. This system enables an operator to operate the robot without the robot's model. The system includes a pneumatic musculoskeletal robot and pneumatic musculoskeletal exoskeleton with same joint and muscle composition. The operator wears the exoskeleton, feels the force that is exerted on the robot via the exoskeleton, and controls the robot by giving force to the exoskeleton. In the experiments, we found that the delay of this system is approximately 200 ms. Our system was able to give feedback force to the operator and change the magnitude of this force according to that of the external force. We showed that the operator can make the musculoskeletal robot perform a task with physical interaction with an environment using our systems. Thus, our system allows the operator to teach motion to a musculoskeletal robot with this interaction.

DOI： 10.1109/ROBIO.2017.8324833

Language：English   Publishing type：Research paper (other academic)  

The ability of a continuum arm is influenced by the performance of an actuator. Although several extensible pneumatic actuators have been proposed in previous research, balancing strength with large strain is still a challenge. We propose an extensible pneumatic actuator with bellows (EPAB) that consists of a rubber tube and a highly packed bellows sleeve. We propose a parametric model of the EPAB that can comprise various bellows and rubber tubes. We measured the basic properties of four actuators with different parameters to verify the proposed model. We conducted evaluation experiments under two conditions: constant length with variable pressure and constant pressure with variable length. The experimental results indicate that the proposed model can roughly predict the measured data. The proposed extensible actuator has an unloaded strain of up to 350% at a pressure of 0.6 MPa.

DOI： 10.1109/ROBIO.2017.8324762

Language：English   Publishing type：Research paper (other academic)  

In this study, a structure-integrated pneumatic cable cylinder has been developed to serve as an actuator for a humanoid robot. The performance of a robot in jumping and hitting a flying object (jump-And-hit motions) has been tested in order to predict its performance during immediate and dynamic whole-body motions. The authors tested the movement of the robofs arms using a cylinder, and jumping motions were simulated to determine the design parameters for the robot performing jump-And-hit operations. Test results for the robofs arms demonstrated that a two-kilogram arm, constructed using a C3, linder with a piston, 32 mm in diameter, moves 75 degrees in 0.44 s. Simulation results for a bipedal robot's forward jumping motion demonstrated that the top of its trunk, with a 50 mm joint force-torque ratio, moves forward by 3.0 m. Using the cylinder for the robofs arms and a joint with the above force-torque ratio in its legs, a prototype of a humanoid robot has been developed that performs a variety of jump-And-hit motions with a ball flying at it from different directions. Thus, the proposed design allows robots to conveniently perform immediate and dynamic whole-body motions.

DOI： 10.1109/HUMANOIDS.2017.8246948

Language：English   Publishing type：Research paper (other academic)  

Environmental and Structural Effects on Physical Reservoir Computing with Tensegrity

Language：English   Publishing type：Research paper (other academic)  

Systems with changeable mechanical properties show promise for expanding the applications of dynamic robots. We proposed the Torque-Angle Relationship Control System (TARCS) for musculoskeletal robots with changeable output properties. First, we formulated TARCS and examined its static properties. Next, we used TARCS to change the properties and investigated the effect of the same on the jumping ability through simulations. We found that TARCS in a biarticular muscle determined the general shape of the jumpable range. Furthermore, TARCS in a monoarticular muscle could change the amplitude of the jumpable range. Both TARCS also changed the directional property of the reaction to the disturbance. Finally, we developed a musculoskeletal quadruped robot in which TARCS was implemented. This robot could change its jumping direction using TARCS, and it jumped to a height of 0.254 m at the lowest point of its body.

DOI： 10.1109/ICRA.2016.7487595

Language：English   Publishing type：Research paper (other academic)  

Elasticity is an important factor in enhancing the physical capabilities of robots. Pole vaulting is an interesting task because a large elastic pole changes the trajectory of the robot drastically. Moreover, the robot can change its behavior by manipulating the flexible pole during a long pole-support phase. In this study, we investigated how the reaching point of pole vaulting was changed by an active bending motion because it is important for robots to move to the desired place. To examine the effect of motion, we used a multiple pendulum model and a robot having dual articulated arms with grippers. Simulation results showed that reaching positions were changed by the switching time of the active bending motion. A relatively late switching time allowed robots to vault to a farther position. However, a very late switching time had the opposite effect. Then, we developed a pole vaulting robot having dual articulated arms with grippers for the application of humanoid robots. Pole vaulting experiments using this robot showed the same tendency in the simulation. These results indicated that the reaching position of pole vaulting could be controlled by the switching time of active bending. Further, the robot reached a height of 1.67 m by releasing the pole.

DOI： 10.1109/HUMANOIDS.2015.7363564

Language：English   Publishing type：Research paper (international conference proceedings)  

Recent studies have demonstrated that active gait training can recover voluntary locomotive ability of paralyzed rats. Rehabilitation devices used for studying spinal cord injury to date are usually fixed on a treadmill, but they have been used only slightly for active training. To process active rehabilitation, a wearable, lightweight device with adequate output is needed. Pouch motors, soft pneumatic actuators, are extremely light and have other benefits such as low cost, easy fabrication, and highly customizable design. They can be used to develop active gait rehabilitation devices. However, performance details of different motor designs have not been examined. As described herein, to build a wearable gait assistive device for rat study, we specifically examine how to design small pouch motors with a good contraction ratio and force output. Results show that pouch performance decreases dramatically with size, but better output is obtainable by separation into small 0.8 length-to-width ratio rooms. We used this knowledge to produce an assistive robot suit for gait rehabilitation and to test it with paralyzed rats. Results show that these small pouches can produce sufficient power to control hip joint movements during gait training. They can reveal the potential for new pouch motor applications for spinal cord injury studies.

DOI： 10.1109/EMBC.2015.7319413

Language：English   Publishing type：Research paper (other academic)  

For robots using elastic devices, pole vault is a particularly interesting task because poles have large differences from previously studied elastic elements in terms of their elastic capacity. The active actuation of the agent in 'pole support phase' plays important roles in improving vaulting performance. Investigating this actuation can contribute to the design of novel control strategies during the time when the agent contacts with environment through the elastic device. In this study, we specifically examined an active bending effect performed in the 'pole support phase.' We analyzed the active bending effect on reachable height (vaulting height) using the 'Transitional Buckling Model.' We applied this active bending theory to a robot and verified the active bending effect to improve vaulting height. Results show that active bending motion in the 'pole support phase' improves the pole vault performance and that the timing of the bending direction change is an important factor for defining the vaulting performance. These results will facilitate the application of robots using large elasticity.

DOI： 10.1109/ICRA.2014.6907471

Language：English   Publishing type：Research paper (other academic)  

Rapid reacting motions are important for robots to adjust to changes in the real world, which is constantly changing drastically. Pneumatic artificial muscles (PAMs) have been used as actuators of fast-moving robots. Robots equipped with PAMs can move adaptively and dynamically using passive properties of PAMs. In this study, we considered preparation for fast reacting motions by robots equipped with joints driven by competing PAMs (antagonistic PAMdriven joints) as using active properties of PAMs. Specifically, we investigated a method of adjusting initial pressures in PAM-driven joints increasing the maximum joint velocity generated in a short time. We found the optimal initial pressure in PAM-driven joints considering a mechanical delay of PAMs in simulations. Additionally, we verified the validity of results in the simulations using an actual robotic arm.

DOI： 10.1142/9789814623353_0022

Language：English   Publishing type：Research paper (other academic)  

When robots make smooth transitions in dynamic motions, they must exert large force over widely various postures. To expand the range of postures that robots can take during dynamic motions, we propose that robots be designed with an Angle-Dependent Moment Arm (ADMA) with biased pivot, for which torque characteristics of actuators attached to joints are adjustable. From jumping simulations of robotic legs designed with ADMA, we demonstrate that ADMA improves robustness to postural and motion timing changes by shifts of the optimal posture, which are also observed in jumping experiments using a full-sized, bipedal robot. © 2014 Taylor & Francis and The Robotics Society of Japan.

DOI： 10.1080/01691864.2013.876936

Language：English   Publishing type：Research paper (other academic)  

Robots must complete motions in a short time in uncertain and variable real world environments. However, uncertainty in the real world has only rarely been considered in studies of agile motions by robots. Consequently, methods for agile motions incorporating uncertainty must be proposed. Preceding agile motions, human preparatory motions (preliminary motions) are often observed. For insight, we specifically addressed human preliminary motions as preparation for agile motion. The effect of preliminary motions on human agile motions has been studied in sports biomechanics. However, no general model of preliminary motion has been proposed. Consequently, findings related to human preliminary motions are difficult to apply to robots. Therefore, we proposed a numerical model of preliminary motions to verify the effect of preliminary motions on robots' agile motions in numerical simulations. Using simulations, we investigated the completion time for reaching motions by simple robot arms. Results showed that robots can prepare and move quickly to an uncertain target using our proposed method of preliminary motions. © 2013 IEEE.

DOI： 10.1109/ICAR.2013.6766534

Language：English   Publishing type：Research paper (other academic)  

Elasticity has been used in many dynamic robots because it can regenerate energy or absorb collision shock. However, the role of elasticity has remained only supplementary. Its potential usefulness in dynamic motion is largely unquantified. Therefore, we specifically examine a task with an extremely large elastic element: pole vaulting. In pole-vaulting research, active operations by an agent are known to improve vaulting performance. Previously, we investigated an active bending effect while hanging from a pole in a simulation. These active operations are generated from the body motion. In this study, we specifically examine the effect of inertial force resulting from motion of the body. We hypothesize that swing-up motion performed closer to the pole planting point (i.e. later in timing) improves vaulting performance. We developed a robot that can exert a large inertial force, and conducted pole-vaulting experiments to verify the hypothesis. Results showed that energy loss is less when swing-up motion occurs later. Our results support the hypothesis and indicate that the timing of swing-up motion is an important factor contributing to vaulting performance. © 2013 IEEE.

DOI： 10.1109/ICAR.2013.6766528

Language：English   Publishing type：Research paper (other academic)  

Angle-Dependent Moment Arm with Biased Pivot for Jumping from Various Squatting Positions

Language：English   Publishing type：Research paper (other academic)  

Transitional Buckling Model for Active Bending Effect in Pole Vault

Language：English   Publishing type：Research paper (other academic)  

Design and Test of Torque-Angle Relationship Control System

Language：English  

Robots mimicking the structure of the musculoskeletal systems have been de- veloped in order to realize high physical performance or to reveal the con- tribution of the musculoskeletal systems to body movements. The movement of center of rotation (CoR) of biological joints have been focused on in var- ious research fields. However, to date, the isolated contribution of the joint displaceable center of rotation (JDCR) on physical performance has not yet been analyzed. Revealing this contribution is expected to provide guidelines for the design methodology of robots. In this paper, we compared two mod- els in order to investigate the effect of JDCR on physical performance. The first model has two virtual links to represent the joint including the JDCR (JDCR model). The second model represents the joint with fixed CoR (JFCR model). We evaluated the two models by analyzing energy consumption during reaching motions. In addition, we examined energy consumption while the end effector traced a circular trajectory using extended models (eJDCR model and eJFCR model). The results showed that the energy consumption of models which include JDCR lower than models which does not under all tested con- ditions. This study suggested that a joint including JDCR can improve energy consumption.

DOI： 10.1142/9789814525534_0036

Language：English   Publishing type：Research paper (scientific journal)  

In this study, a musculoskeletal robot is used as a tool to investigate how animals control their complex body. Sprinting is a challenging task that requires maximizing the potential resources of a musculoskeletal structure. Our approach to robotic sprinting is the Athlete Robot - a musculoskeletal robot with elastic blade feet controlled by feedforward motor command. We use a catapult launcher to provide a stable start to a sprint, and then examine the relation between the initial velocity imparted by the launcher and the change in orientation of the robot. We also investigate the influence of the change in elasticity of the blade foot. The results show that acceleration causes anterior inclination after the first step. The elasticity of the foot dominates the duration of the support phase. The musculoskeletal system of the Athlete Robot is modified to suit catapulted running. Based on the results from real robot experiments, we can provide a consistent propelling force using the catapult launcher. We demonstrate the Athlete Robot running for five steps after a catapult launch, using only feedforward command. © 2012 Koninklijke Brill NV, Leiden and The Robotics Society of Japan.

DOI： 10.1163/156855311X614635

Language：English   Publishing type：Research paper (other academic)  

Running Motion in a Musculoskeletal Bipedal Robot using Muscle Activation Pattern Control Based on a Human Electromyogram

Language：English   Publishing type：Research paper (other academic)  

To gain a synthetic understanding of how the body and nervous system co-create animal locomotion, we propose an investigation into a quadruped musculoskeletal robot with biologically realistic morphology and a nervous system. The muscle configuration and sensory feedback of our robot are compatible with the mono- and bi-articular muscles of a quadruped animal and with its muscle spindles and Golgi tendon organs. The nervous system is designed with a biologically plausible model of the spinobulbar system with no pre-defined gait patterns such that mutual entrainment is dynamically created by exploiting the physics of the body. In computer simulations, we found that designing the body and the nervous system of the robot with the characteristics of biological systems increases information regularities in sensorimotor flows by generating complex and coordinated motor patterns. Furthermore, we found similar results in robot experiments with the generation of various coordinated locomotion patterns created in a self-organized manner. Our results demonstrate that the dynamical interaction between the physics of the body with the neural dynamics can shape behavioral patterns for adaptive locomotion in an autonomous fashion. © 2011 IEEE.

DOI： 10.1109/IROS.2011.6048360

Language：English   Publishing type：Research paper (other academic)  

The essential component of legged locomotion is control of the ground reaction force. To understand the role of the musculoskeletal body in dynamic locomotion, we investigate bipedal running using a musculoskeletal "Athlete Robot". The configuration of the muscles in the robot is compatible with the human. The spring-like property of the human lower leg during running is modeled as an elastic blade foot based on findings from biomechanics. The motor command of the robot is represented by time series data of muscle activation. The muscle activation patterns are determined from numerical calculation using a model of the musculoskeletal leg based on the measurement of muscle activity and kinetic data of the human movements. In the simulation results, the robot runs 8 steps with a speed of 3 m/s. We also demonstrate that the real bipedal robot is able to run for several steps. ©2010 IEEE.

DOI： 10.1109/ICHR.2010.5686316

Language：Japanese  

Country：Japan  

A study on fall prevention assist during turning with a lower-limb power-assist robot

Language：English  

Country：Japan  

Generation of shoulder internal and external rotation motion illusion with simultaneous stimulation of skin stretch and vibration

Language：Japanese  

Country：Japan  

Pneumatic humanoid robot with adsorption mechanism for badminton stepping motion
In this research, we developed a humanoid robot with suction mechanisms to realize footwork in badminton. First, the investigation of the suction force of suckers showed that the stability of the robot had improved. By improving the stability, the robot was able to perform a large and quick-stepping motion that was not possible with existing robots. The width of the step was about 0.9m, and the horizontal velocity of the hip of the robot was about 1.1m/s. Compared to the human stepping motion, the speed of the robot’s stepping motion was inferior, but the width of the step was no inferior. In addition, the estimated ZMP during the stepping motion showed the effectiveness of suction mechanisms in the realization of badminton footwork.

Language：Japanese  

Country：Japan  

Wearable device to inhibit wrist dorsiflexion for movement form improvement in table tennis backhand
In this research, we developed a device that suppresses dorsiflexion of the wrist in the backhand action of table tennis and verified that the device improves the movement form of the player. To test the device, an evaluation experiment was conducted with four subjects in the experimental group and four subjects in the control group. Comparison with the control group revealed that all but one of the three subjects in the experimental group tended to suppress wrist motion when wearing the device and to swing while utilizing their elbows. When the device was removed, the three subjects tended to move their wrists less than before and to swing with their elbows, indicating an improvement in their form.

Language：Japanese  

Country：Japan  

Generation of the illusion of forward reaching motion by vibratory stimulation of upper arm-related muscles
In this study, we proposed a method to generate the illusion of arbitrary hand motions in daily life by generating vibration frequency patterns proportional to the angular velocity and angular acceleration of the shoulder and elbow joints associated with the target hand motion. To verify the effectiveness of the proposed method, the verification experiment to generate motion illusions of reaching forward and returning to the initial posture at a constant speed by integrating motion illusions of the shoulder and elbow joints was conducted. And the oscillation frequency pattern proportional to the angular acceleration is effective in generating the illusion of arbitrary hand motion was concluded.

Language：English  

Country：Australia  

Language：Others  

Country：Japan  

A Study on Intended Lower-Limb Motion of Elderly Persons-Realtime intended motion and phase estimation-

Language：English  

Country：Japan  

Real-time Early Handwriting Character Prediction with EMG for Upper Limb Exoskeleton Perception Assist

Language：English  

Country：Japan  

Evaluation of normal walking with hip joint trajectory for lower- limb perception-assist

Language：English  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Others  

Country：Other  

Language：English  

Country：Japan  

Kinesthetic illusion of knee joint motion induced by vibration stimulation on the quadriceps femoris muscle during continuous motion

Language：Japanese  

Country：Japan  

1A2-A07 Muscle Activation Pattern Control for Running of Musculoskeletal Robot
Despite the considerable complexity of the human musculoskeletal system, human beings are capable to move with great dexterity and ease even under instable conditions as during running. In order to understand the control mechanisms underlying the generation of such skill-full behaviors, we propose to study running, a highly dynamic motion, using an anthropomorphic bipedal robot. To do so, we propose a method called Muscle Activation Pattern Control based on physiological observations of athlete runners that we apply in a simulation of our running robot. Using this method, we show that the robot can autonomously acquire patterns of running motion over 3m/s.

Language：Japanese  

Country：Japan  

床反力制御による筋骨格ヒト型ロボットの走行

Language：English  

Venue：Nantes, France   Country：Other  

Emergent Locomotion Patterns from a Quadruped Pneumatic Musculoskeletal Robot with Spinobulbar Model

Language：English  

Venue：Nantes, France   Country：Other  

Dynamic Motions by a Quadruped Musculoskeletal Robot with Angle-Dependent Moment Arms

Language：Japanese  

Venue：愛知   Country：Other  

Motor Learning by Phase Division with Sparse Coding of Muscle Activation

Language：Japanese  

Country：Japan  

筋骨格系駆動のヒト規範足部を備えたロボットによる跳躍

Language：Japanese  

Venue：大阪   Country：Other  

Musculoskeletal Quadrupedal Robot with Variable Distribution Ratio of Joint Torque

Language：Japanese  

Country：Japan  

Language：Others  

Country：Japan  

Language：Others  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Others  

Country：Japan  

Language：Japanese  

Venue：東京   Country：Other  

Resisting motion to improve vaulting performance in pole vault

Language：Japanese  

Venue：東京   Country：Other  

Body-Pole Coordinated Motion from the Pole Bending Perspective in Pole Vault

Language：Others  

Country：Japan  

Language：Japanese  

Country：Japan  

1P1-P03 Preliminary motions for minimizing transition time to probabilistically-variable target states(New Control Theory and Motion Control (1))
Rapid reacting motions should be needed for robots working in human environments. Preliminary motions are expected to improve speed of such motions. Thus, we investigated preliminary motions in such complex environments. In this investigation, we calculated expected value of minimum time for state transition of a simple robotic arm model. In addition, we compared the value of cyclic motions with stopping as preliminary motions. As a result, we found that stopping states make speed of reacting motions more fast when target states can be predicted enough and cyclic motions may make the speed more fast when it is difficult to predict target states.

Language：Japanese  

Country：Japan  

1A1-A08 Effect of Bi-articular Spring-damper System on Disturbed Pole Vault(Mechanism and Control for Wire Actuation System)
Pole vault is an interesting task because of its high performance using a large elastic element. Although previously we showed that active bending motion is effective to improve pole vault height, it was sensitive to disturbance. In order to stabilize pole vaulting performance, physical feedback is important because of its quick response. Therefore, we focused on musculoskeletal system, especially its bi-articular spring-damper system, and investigated its contribution to stabilization of pole vaulting. We compared pole vaulting performance of a non spring-damper model, a mono-articular spring-damper model and a bi-articular spring-damper model in simulation on the disturbed condition. As a result, we found that the mono-articular spring-damper model and the bi-articular spring-damper model tended to be reduce negative effect of large disturbance at early timing of pole bending motion. In addition, bi-articular spring-damper model had intermediate response characteristics to disturbance between other two models. These results implicate that musculoskeletal system contributes to stabilize pole vault.

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Others  

Country：Japan  

Language：Japanese  

Country：Japan  

Language：Others  

Country：Japan  

Language：English  

Country：Singapore  

Compliant Jumping Mechanism with Bi-stable Structure

Language：Japanese  

Country：Japan  

Reservoir Computing with Body Structures and Dynamics
<p>Some actual creatures calculate not only on their brain but also on their body itself. This is called morphological computation. Physical reservoir computing, which uses body itself as a neural network like system, is one approach of the way of morphological computation. The purpose of this research is to understand the effect of body structure and environment around it by the experiments with Tensegrity structures. When spring constant was large, structures were hard to move and dropped its ability. When input amplitude was large, input could counteract the effect of past input and dropped its ability. In addition, the environment around the body especially how to contact with ground (coefficient of restitution) gave large effect on calculation. With ground, the convergence oscillation's period and amplitude changed.</p>

Language：Japanese  

Country：Japan  

Development of a structure integrated pneumatic cable cylinder robot executing a jump-hit motion
<p>Humanoid robots must execute situation-adaptive whole-body dynamic movements to protect humans. However, design of such robots have been unclear. Thus, our aim is to clarifying a design method of a robot executing a jump-hit motion representing these movements. For such a robot, we developed a light, high power and large stroke pneumatic actuation system equipped with a cable cylinder integrated in a link structure and made of custom-made plastic parts. We developed an arm robot, a leg robot, and an arm-equipped legged robot with this system and evaluated their physical performance. In experiments, the developed robot executed different jump-hit motions against a ball flying from the different directions.</p>

Language：Japanese  

Country：Japan  

Control of the handspring robot with rolling-jumping locomotion
<p>The continuous motion composed of rolling and jumping such as continuous handspring is useful as the locomotion of robots. In order to realize the continuous handspring, we propose a multi-link robot model composed of two limbs and a body and the control law for the model. We verified the controller using the combination of attack angle control and the control based on the angular momentum of the robot in the simulation. In the verification, the robot model realized 100,000 steps in the continuous handspring in the certain environment. In addition, it realized 20 steps after the temporary change of coefficient of static friction of the floor from infinity to four and over in the verification of the robustness against the temporary disturbance.</p>

Language：Japanese  

Country：Japan  

Development of humanoid robot arm for badminton with high accelerration and high speed wrist
<p>Badminton needs dynamic and high speed motion, so previous humanoid robots were difficult to perform like human. For entertaining or training humanoid badminton robot in the future, we propose new robot arm which consists of structure integrated pneumatic cable cylinder and noninterfering many DoFs joints. We made a real robot arm with high acceleration and high speed wrist and conducted some performance evaluation test. Pronation joint achieved 32.4rad/s in 90 deg, which surpasses human wrist speed in badminton smash. It has also good reproducibility for dynamic feed-forward control or learning control. We also make it hit actual shuttle, and shuttle's initial velocity achieved 28m/s by full swing. And it succeeded skillful shot, spin hairpin, by utilizing the humanlike wrist. This research is the first step toward humanoid badminton robot.</p>

Language：English  

Country：Other  

Compliant Jumping Mechanism with Bi-stable Structure

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Development of pneumatically actuated musculoskeletal humanoid for dolphin kick research
<p>The dolphin kick is the swimming style with an undulation of a body conducted after start and turn. Practicing dolphin kick is one of the effective way for improving swimmers' record. It has been researched using real swimmers, simulation and robots. Dolphin kick research requires a combination of these methods. However, existing robots have inadequate points including their body size and lack of a flexible spine. Thus, we developed human-scale pneumatically actuated musculoskeletal humanoid called Triton. It has flexible spine and adjustment system for lumbar joint stiffness. We conducted preliminary experiments that compare time-series of thrust force and joint angle between Triton and experimental results with simulations and human data.</p>

Language：Japanese  

Country：Japan  

Reduction of the Effect of Spinning Ball in Table Tennis by High Speed Swinging using Flexible Arm
<p>In table tennis robots, a spinning ball is difficult to be returned to the opponent court because its direction of bound is dependent on the spinning direction and amount. We aimed to solve this problem by swing motion that is robust over a large range of spinning pattern without accurate recognition of spinning. Specifically, we examined the relation between swing speed and returning direction. When the racket speed was 7 m/s, the difference of returning direction reduced to 20 % compared to no swing against the spinning ball in the range from -20 rev/s to 20 rev/s. In addition, we focused on the flexibility of swinging arm to increase the swing speed. We found that a flexible arm swung faster than a rigid arm in the whole range of motion when exploiting the joint angle limit.</p>

Language：Others  

Country：Japan  

Language：Japanese  

Country：Japan  

Throwing a Ball of the Pneumatically-Controlled Continuum Robot Arm using Reinforcement Learning with Movement Primitives
<p>Previous research on reinforcement learning for continuum robot arms have been dealt with a relatively small number of active degrees of freedom and made experiments of simple tasks such as reaching. We aimed to learn to throw a ball by reinforcement learning in a pneumatically-controlled continuum robot arm that has nine actuators. We adopt Cost-regularized Kernel Regression (CrKR) which uses dynamic movement primitives (DMPs) which is one of the movement primitives. In the simulation, the continuum arm was able to learn how to throw a ball forward. We made the same experiment for our real continuum robot arm and found that the learning progressed in the experiment.</p>

Language：Japanese  

Country：Japan  

Competitive physical interaction by reinforcement learning agents using predictive models
<p>Though there are a lot of researches about Physical Human-robot Interaction (pHRI) using prediction, few researches work on inducing the opponent's action or outwitting the opponent. We made the push-hand game environment in order to focus on generating strategic actions and tried to make reinforcement learning agents to learn these actions by adding rewards which are directly proportional to the degree of inducement (induction reward) or the degree of outwitting (outwitting reward), defined in this research. As a result, we demonstrated that the induction reward decreases the agent's predictive error and the outwitting reward increases the opponent's predictive error, and both of them didn't contribute to the winning percentage.</p>

Language：Japanese  

Country：Japan  

QOL Estimation based on Multimodal Learning through Interaction with a Communication Agent
<p>When a monitoring system or a communication robot for the elderly welfare interacts with a human, it is important to estimate the user's state and to generate a behavior based on it. In the field of welfare for the elderly, quality of life (QOL) is a useful indicator, not only for human physical suffering, but also for treating mental and social activities in a comprehensive manner. In this study, we propose a QOL estimation approach that integrates facial expressions, head movements, and eyes movements in the process of interaction with a communication agent. To this end, we implemented a communication agent and constructed a database based on the information collected through communication experiments with humans. In addition, we implemented a multimodal learning estimator that incorporates C3D, a three-dimensional convolution and performed learning with head fluctuation and gaze feature extraction. Our results show that multimodal learning that integrates all of facial expressions, head fluctuations, and eyes movements was realized with less error than single modal learning using each feature separately. From our experimental results, we concluded that the proposed system can be used sufficiently as a QOL estimator.</p>

Language：Others  

Country：Japan  

Mental Health Score Estimation System Based on AdaBoost

Language：Japanese  

Country：Japan  

Language：Japanese  

Country：Japan  

Motion generation of a soft sheet-like swimming robot using physical reservoir computing
In recent years, swimming robots have been developed to achieve efficient propulsion and high maneuverability. Previous researches have tried to achieve fish-like swimming by control based on physical models and top-down architectures, but have encountered problems due to high complexity of the underwater environment. Other researches have tried to overcome these problems by mimicking the physical properties of fish. To achieve more intelligent swimming, we argue that a control architecture that uses physical dynamics as a computational resource is needed. In this study, a soft sheet-like swimming robot achieves motion emulation and environment estimation through a control architecture based on physical reservoir computing.

Language：Japanese  

Country：Japan  

A study on mismatch feeling discrimination using EEG during ankle joint movement

Language：English  

Country：Japan  

Balance Analysis of Slope Walking for Fall Prevention of a Lower-limb Power-assist Robot

Language：Others  

Country：Other  

Language：Japanese  

Country：Japan  

A Study on Real-Time Accident Prediction using Depth Information for Perception-Assist in Lower-Limb Power-Assist Robot

Language：Others  

Country：Japan  

Language：Japanese  

Country：Japan  

A study of shoulder extensor muscles and vibration conditions suitable for generating the illusion of shoulder joint flexion using vibration stimulation

Language：Japanese  

Country：Japan  

Development of a pneumatic assist suit that assists the twisting movement of the lower body during the forehand swing of table tennis

Language：Japanese  

Country：Japan  

A Study of the Relationship between the Timing of Intervention Movement in the Anterior-Posterior Direction and Human Postural Response for Motion Guidance by Robots

Language：Others  

Country：Japan  

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc.