This paper focuses on the control of dynamic systems under the case that actual reference signals can not be available in real time. In such case, although a predicted value values are used as reference signal, the prediction errors degrades the control performance of the systems. To this problem, the previous work has presented the prediction governor which shapes predicted values.However, the previous result can not be applied to non-linear systems. Motivated by this, this paper addresses the design problem of prediction governors for input affine non-linear systems. Then, we analytically derived an optimal prediction governor which is characterized by plant models. Furthermore, we applied it to the automatic cruise control problem, and its usefulness is illustrated by a numerical example.

Actuators that have characteristics such as light weight, high thrust to weight ratio, and force controllability are desired for finger robots or power assist suits. Recently, an indirect force control method using an ultrasonic motor (USM) and a linear spring has been attracted attentions because the method has a potential to satisfy both of light weight, high thrust to weight ratio, and force controllability. Although some researches have tried to improve a control bandwidth by using a resonance ratio controller, those researches assume that a USM achieves a perfect position control. This research therefore assumes that a transfer function from a position reference to a position response of an USM is modeled by a first-order system, and control performance and stability of some indirect force control systems using USM are analyzed. The validity of the analysis is verified by simulation and experiment.

Recently, bilateral teleoperation system using an electric helicopter as a slave robot has been researched. Although conventional methods utilize a static controller, an unignorable position/force tracking error is induced by grand effect. A propeller's angular velocity-thrust force characteristics changes depending on a distance between a helicopter and a grand due to grand effect. This paper therefore proposes a gain scheduling controller which changes the controller gain depends on a distance between a helicopter and a grand. The validity of the proposed controller is verified by experiment. The validity of the proposed control system is verified by experiment.

In a conventional balance control method, the target object is modelled and the control parameters are determined. However, if there are changes in the model parameters, such as weight or length, after determining the control parameters, the control may become unstable. To solve this problem, we propose a method to adaptively adjust the control parameters during operation even if the quantitative model of the control target is not given. As a typical example, we chose the case of stabilization an inverted pendulum using a flywheel, which is a classic problem of balance control. The time series data of the state of the pendulum of different sizes were obtained and used to train the neural networks to obtain optimum control parameters. The usefulness of the proposed method through simulations.

This paper proposes a method for reaction force estimation in R/C Servo Motors. External force measurement is an essential technique in robotics and there are demands on sensorless force sensing. Reaction force observer using a voltage control driver is introduced for sensorless reaction force estimation. In the system that adopts a voltage control PWM drivers, it is necessary to consider the influence of the skin effect. This method can be implemented without changing the setup of the existing R/C Servo Motor. The performance of this method is evaluated by the experiment applying force to the portable ankle training robot.

This paper proposes a trajectory planning method with deep neural network (DNN) which is trained by model predictive control (MPC) for dynamic manipulation. The novelty of this method is that trained DNN can receive target positions and environmental parameters to generate trajectories. The proposed method solves dynamic manipulation using dynamic constraint of the object with low calculation cost. This paper shows the effectiveness of the proposed method by demonstrations that a robot turns over pancakes under various parameters.

Medical applications of ultrasound are expanding as a minimally invasive treatment method. There are HIFU and MDS in ultrasonic therapy. In these therapeutic methods, robotic positioning of therapeutic devices on body surface is required. In order to position the robot, it is necessary to acquire the position coordinates of the therapeutic part inside the human body. Therefore, we proposed a system that acquires target position from the ultrasonic volume data acquired using the ultrasonic probe. In this paper, we describe the flow of treatment by the proposed robot. Next, we describe the configuration of the system. Furthermore, we describe the target position coordinate acquisition algorithm and the bifurcation point position acquisition algorithm. Then, we performed the accuracy evaluation of the acquisition of the target position coordinates. The accuracy was about 1.3 mm. We showed that we can acquire target position from ultrasonic volume data.

Microbubbles are expected as carriers of acoustic targeted drug/gene delivery therapy. Because microbubbles diffuse in human body after injection, we have proposed a technique that controls catheter which can deliver microbubbles directly to the target position in blood vessels using ultrasound emitted from the body surface. To apply this technique in vivo, robotic positioning of therapeutic devices on body surface is required. For this purpose, we have developed a robotic system using parallel link robot, which has both diagnostic/therapeutic devices. In this paper, first we describe the algorithm of ultrasonic catheter control system. Then, we performed the accuracy evaluation of focal point using robotic positioning. The accuracy was about 1.5 mm, which is less than the beam width of sound pressure distribution. Finally, we demonstrated the ultrasonic catheter control experiment at the bifurcation of in vitro blood vessel and the catheter was controlled to the target path in 100% induction rate.

In this paper, two improvements of the forceps manipulator used in the robotic surgical system for single port surgery (SPS) developed in our previous study were performed. First, the bending mechanism of the detachable forceps manipulator attached to the arm robot in the robotic surgical system for SPS was improved so as not to give a damage to the wire for actuation, in which a screw drive mechanism was employed to the improved bending mechanism. A new detachable forceps was built, and its movability was verified. Second, the parts for fixing the six-axis force/torque sensor to the forceps rod were improved, since the operated force to z-axis direction was not detected stably. New fixing parts were built, and experiments were carried out to evaluate the effectiveness of the improved fixing parts. The results showed that the operated force was detected stably in all axis directions.

Laparoscopic surgery is a difficult surgical procedure as compared with open operation. Therefore, training is necessary for surgeons to perform laparoscopic surgery. In this paper, a training system in which trainees can train a process by themselves that makes a forceps arrive at the target position during ligation based on the evaluation results of hands movement and an operation time, is proposed. First, an acceleration of the forceps is measured by 9-axis sensors attached to the forceps and frequency analysis is performed to the measured acceleration. When the spectrum of the trainee's acceleration in low frequency band is larger than the threshold value determined from pre-measured spectrum of the skilled surgeon's acceleration, the hands movement is regarded as superfluous. Second, an operation time of the trainee's forceps operation which makes the forceps arrive at the target position during ligation is compared with that of the skilled surgeon. Finally, the evaluation results of trainee's hands movement and operation time in comparison with those of the skilled surgeon are displayed on the monitor screen.

We have been developing a prenatal care robot for supporting an ultrasonic diagnosis. In this paper, we intend to develop a core function for both obtaining clear images without lacks and ensuring a safety of pregnant women. In order to minimize the lack, the ultrasonic probe is operated for maintaining it perpendicular to the body surface. For safety, the number of actuators achieving those motions is minimized and most joints are moved passively. From results, it was confirmed that the ultrasonic probe follows the body surface smoothly and touches approximately vertically. We show the possibility of the proposed function for obtaining images with little lacks.

This study investigates the operational influence of the force feedback with the five-finger robotic hand using master-slave control on surgery supporting system. We considered the tactile requirements of hand-assisted laparoscopic surgery (HALS) and specification of the surgery support robot and design the force feedback device. The device can feedback the corresponding force and will not obstruct the surgical behaviors. The device consisted of a mobile surface, which interacts with the fingertip, actuated by a wire directly connected to the motor. According to the result of our experiment, the dimension and the scratchability can be perceived through power grasp. In addition, when we execute the precision grasp, we can detect the exist of the organs.

In recent years, researches on manipulation systems that can respond quickly to changes in the environment are increasing. Our research group has studied a juggling robot as one example of them. If the robot is a multi-joint manipulator and moves at high speed, the influence of the dynamics of the robot can not be ignored. Our previous studies have mainly used simple PD control based on the difference between the target joint angle and the actual angle. However, due to the influence of dynamics, tracking errors remain at high speed operation. In order to solve this problem, in this paper nonlinear model predictive control (NMPC) is applied to a high speed robot. Since NMPC has a large calculation load, it applies only to axes with large tracking error. Experimental results are shown to verify the proposed method.

We have proposed motion planning method to speeding up tracking hand speed for path tracking task with constant hand speed. The conventional methods have problems that the methods cannot apply to generalized manipulators and need long calculation time. In this paper, we propose a motion planning method to adopt genetic algorithm. In order to adopt genetic algorithm, we must resolve a new problem. The new problem is a lag between to be required output timing and output timing having genes. We resolved the new problem by estimating output of required timing using fuzzy estimation. The proposal method can apply to generalized manipulators and became calculation time short.

An application of the uncertainty and disturbance estimator (UDE) to the control of a two-link manipulator is shown in this paper. The UDE-based control consists of a tracking controller that uses a reference model and a compensator for the rejection of uncertainty and disturbances. An experimental result of the position control of a two-link manipulator shows that the UDE works with some flaws. Also, we show that the structure of the UDE is very similar to that of the disturbance observer (DOB).

In this research, we consider a posture control problem of the planer two-link torque unit manipulator under viscous friction condition. The torque unit is a module consisting of an electric motor and a reaction wheel. It can be set at an arbitrary position as an actuator to control a rotating link system with a free joint. When a manipulator is controlled by torque units, a problem arises: angular momentum remains in the reaction wheel of the torque units. It is therefore important to consider a method of unloading the residual angular momentum. In this report, we propose the method to control the first link to the arbitrary reference position by using the viscous friction on the first joint. Then, we show the feasibility of the proposed method by making several verification experiments.

This paper presents a new kinematics algorithm for branched chains, Asynchronous Forward Kinematics (AFKB). The algorithm has the complexity of O(log n) for updating one joint angle, and O(log² n) for obtaining a transformation matrix between links. AFKB enables computation for efficient forward kinematics under asynchronous sensory data. Moreover, AFKB enables to localise computational resources at sensitive joints to the position of the end point (e.g. the fingertip), like a root joint. We provide implementation results including computation time, comparing AFKB and the conventional forward kinematics (CFK). The results showed that the computation time is effective enough for real-time computation. For instance, computation time for 50 links takes less than 60 us for 1 query. Moreover, computation time with over 100000 links takes less than 280 us for 1 query.

Various articulated robots have been invented one after another. However, there are some difficulties in modeling when creating the robots. In this study, we model an articulated robot with an unknown structure using an inexpensive and compact sensor. In addition, in order to use inexpensive sensors, we also develop a method to easily calibrate the sensor.

In this paper, a gripper for the forceps using a soft actuator, which can estimate the gripping force, is proposed. The gripper consists of a small cylinder and a slider-crank mechanism embedded in the tip of the forceps. The developed soft actuator has a built-in strain gauge to measure the displacement of the actuator. By combing the measurements of the strain gauge and the internal pressure, it can estimate the external force. The experiment with the same protocol is conducted while the gripper grasps a force sensor. A master slave system is constructed using the girpper.

We propose a method to remove residual air bubbles in the arterial filter by vibrating device. This device provides usability to reduce the bubble removal time and the Individual differences due to skill level of clinical engineers, as residual bubbles can be removed mechanically. In this paper, we analyze the relationship between the design of this vibration device and vibration during operation, and confirmed that the operation of this device is operating based on the design. We confirmed that the operation of this device is operating based on the design. In other words, the design is considered to deserve recognition as a useful design.

In this paper, a pneumatically driven robotic forceps with tip rotation mechanism is proposed. The forceps have 2 degree of freedoms (DOFs) for bending joint, tip rotation and a gripper. The outer diameter of the forceps is 5mm. The bending joints and gripper is driven by pneumatic cylinders and rotation is driven by a pneumatic vane motor. The gripping and the rotation can be drive at the same time by drilling a hole at the shaft of the vane motor to pass the driving wire of the gripper. The forceps is suitable for suturing tasks, since only the gripper portion of the forceps rotates in this tip rotation mechanism, fine rotation operation is possible. The control performance of the prototyped forceps is evaluated experimentally.

Pericardiocentesis-assist device is necessary for reducing medical accidents. One of the elements constituting the pericardiocentesis-assist device is a cutting mechanism of the pericardium. In this study, we aimed to identify the mechanism that the proposed device could cut the pericardium. We designed two types of cutter, the carving knife type and the scissors type. As a result of comparison experiment, the scissors type cutter was able to cut the mock pericardium.

A new mechanically separable master device has developed that can be autoclave sterilized to master-slave control for a surgery support forceps manipulator (LODEM) with five-DOFs. The master device is separated into the handy mechanical part and the encoder sensor part connected to driving wires. The mechanical part uses a ball joint and gimbals for pitch and yaw axes, and linear guide for insertion axis. The operating range is ±70° for the pitch and yaw axes, and 0 to 100 mm for the insertion/extraction axis. The dimensions and the mass of the mechanical part are 126*126*345 mm and 1.0 kg. The dimensions and the mass of the sensor part are 160*87*200 mm and 1.4 kg. The backlash was 0.8°, 1.8°, and 0.6 mm respectively.

Researches on the wearable power assist device has flourished in recent years. In previous study, we paid our attentions to jump movement in particular and developed a SDF prototype of the device amplifying the knee ability for jumping motion. We conducted modeling and experiments to investigate leap characteristics of the equipment alone and confirmed the validity of modeling 1 DOF prototype. However, we would speculate that ankles play the important role in jumping motion of human. Thus, in this study, we propose new model of the device and report a characteristic and fundamental experiment of the TDF prototype we developed.

In this study, a variable viscoelastic joint system comprising antagonized artificial muscles and magneto-rheological fluid brakes is proposed. This system enables human assisting devices such as robotic exoskeletons to retain structural softness when compared with the existing devices driven by motors and reduction gears, which can only achieve superficial softness. The authors had proposed the system and showed its effectiveness via experiments using a prototype with one degree of freedom in their previous works. In this study, as the next step in designing the human assisting device, a lower body assistive prototype “Airsist I” is introduced. In addition, a control method that can cooperate with the wearer without the need for an additional operation is proposed.

In recent years, the shortage of physiotherapists in nursing care has been pointed out. In order to support and assist physiotherapists, it is desirable to develop the rehabilitation robot. This paper describes the development of wearable wrist rehabilitation training device using parallel-link mechanisms. It is possible to train translational and rotational motion of the wrist joint. And, this device has reversible characteristics by the adoption of shaft motor. In experiments, the palmar flexion and dorsal flexion motions of 9 subjects were trained with a set of training data. Further, motion data during the training was recorded by a camera. The motion data was evaluated using a Correlation coefficient, and it was judged whether the training data is suitable for the trainee.

Declining birthrate and aging society means increasing in older workers or care receivers, and decreasing in young workers or caregivers. As the countermeasure, research for development of wearable robot is carried out in many places. Muscle suit that has high power and high compliance is one of the research results. However, in order to execute the assist operation at an appropriate timing to the wearer, it is necessary for the device to constantly follow the wearer. Even with the assist system, there was a problem that the assist operation was performed at an unintended timing. Therefore, we examined the motion recognition system using IMU and wire detection and the execution condition of the assist action. In this paper, we report the control system of electric muscle suit using IMU and wire detection.

This paper proposes an MRI compatible tapping assistive robot that supports a human moving his fingers voluntarrily and involuntarily in high electromagnetic field. The exoskeleton of the robot consists of four exoskeletal fingers excluding a thumb, which is fabricated with non-magnetic materials through 3D printing. In order to be used in an MRI environment, pneumatic actuators are applied to drive the joints of the wearable robot. Potentiometers are installed in the MP and PIP joints of four fingers to measure the angles of finger's motions. Basic performances of robot are evaluated by flexion rang of fingers and fingertip force. In the future, we will confirm the compatibility of robot in MRI environment through some measurement experiments of a subject's brain activity.

In this paper, we developed two knee assist exoskeletons with a variable stiffness mechanism. These exoskeletons support human knee torque through increasing the stiffness during stance phases and decreasing the stiffness during swing phases. We conducted experiments to evaluate the assist effects. In the experiment, we compared three conditions: the subject did not wear the exoskeleton, the subject wore the exoskeleton and the exoskeleton did not support torque of the subject, and the subject wore the exoskeleton and the exoskeleton supported torque of the subject. We measured metabolic energy of the all conditions. As a result, we verified that the variable stiffness exoskeleton reduce 13.4[%] of metabolic energy. We made an improved exoskeleton that is 1.2[kg] lighter than the old one, and has a variable stiffness mechanism using not a servomotor but an electromagnetic clutch. This mechanism can realize more quick stiffness adjustment and energy saving. We verified that this improved exoskeleton can adjust stiffness.

There are a lot of caregivers who suffered lumbar pain. Although the main cause is thought to be transfer aid, meal assistance also cause the lumber pain because this assistance import burden on the lumber spine for a long time. Therefore, we develop a wearable device which can reduce load on the lumber spine in this research. The device under development can keep a halfcrouching position with using exoskeleton mechanism, so that flection of the spine is diminished during work and stress of the intervertebral disc is decreased. Because the device adapts linear mechanism for increase manipulability of legs, it has an advantage over the other developed exoskeleton device.

This paper reports the stereoscopic model of three-dimensional blood vessel having a temperature Indicator for measurement of temperature variation during surgical training. This model consists of two hydrogel materials to mimic Young's modulus of human artery and rapid fabrication of the model using photo-polymerization. Polyethylene glycol diacrylate (PEGDA) is used for photo-crosslinkable resin and polyvinyl alcohol (PVA) is used to mimic surface properties of the blood vessel. Reversible temperature indicator is impregnated into the blood vessel model to visualize the temperature change of the model. The vessel model is fabricated by dip coating on the wax model, photo-polymerization, and lost wax method. We demonstrate color change of the fabricated vessel model by heating of the model.

In this paper, a master-slave integrated 6-Dof surgical robot operated by an elastic-body is proposed. Its rotational motions are manipulated by a controller using the elastic-body which is integrated in the proximal end of the robot. Its translational motions are directly operated by the surgeon. The controller allows the surgeon a wide range of motion, an intuitive operability, and a variable operational scale. We designed the elastic body and developed a control law. Finally, we confirmed the position control performance of the robot experimentally. We evaluated muscle fatigue of the arm using EMG during an operator performs a task using developed operation unit.

A new spherical-coordinate manipulator with circular telescopic rail driven by slider-rocker mechanism has developed that can operate within a small space while providing a wide working area on the abdominal wall. The manipulator uses a circular telescopic rail in both directions driven by Rapson's slider for Pitch axis, rotation mechanism above pivot point for Yaw axis, and rack and pinion mechanism for Insertion axis attached to the forceps. The operating range is ± 45° for the pitch axis, ± 90° for the yaw axis, and 0 to 200 mm for the insertion/extraction axis. The dimensions of the manipulator are 230*215*295mm. The mass is 1600g. The positional accuracy was 1.3mm, 0.6mm, and 3.6mm respectively. The deflection of the mechanism was 4.9mm, 2.9mm, and 3.0mm respectively. A mechanism of Compact LODEM 2.0 was designed that allows minimally invasive robotically assisted endoscopic surgery.

Palpation is a diagnosis method that physicians get information about organ by using touch sensation. However, palpation is a subjective method, and accuracy of diagnosis depends on physician's experience and skill. Therefore, in order to make palpation objective and more accurate, a palpation sensor system has been required. In previous study, we proposed an artificial soft finger system to palpate a prostate gland. The artificial finger was composed of a silicone cylinder, wires, and two motors. Two wires are connected with motors through the silicone cylinder. And the artificial finger turns in various directions according to length of wires. And we obtained a relation formula for estimating the fingertip position from the length of wires. In this paper, we proposed an estimation method of hardness by using the artificial finger system. And to realize the method, mechanical characteristics of the finger part was obtained by experiments.

Recently, according to the research of Ministry of Health, Labour and Welfare, around 60% of workers suffer from low back pain in Japan. For that reason, we developed a wearable assist device “AB-Wear” aimed at reducing back pain.The assist suit is equipped with mechanism to reduce spine compression. This mechanism is made of flexible flat plate, and wearer can move naturally. First of all, we explain the detail structure of AB-Wear. And assist effect is confirmed by musculoskeletal simulation using assist suit model and musculoskeletal model. Finally effect of compressive force reduction mechanism to human complex motion is confirmed by torsion experiment on wearing the suit and without suit.

Paralysis of lower limb due to apoplexy causes limitation for daily life. Rehabilitation in convalescent stage is important to recovery of paralysis. The purpose of this study is to develop a power assist device like normal clothes to assist rehabilitation. This device called ‘Power Assist Wear’ is constructed with body and lower limb supporters, McKibben type artificial rubber muscles. In previous studies, flexion at hip joint had been assisted by using proposed device. In this study, correction of lower limb, which moves to adduction and adduction directions is realized by using this wear. 　 In this paper, the control method for correction of lower limb is described, and then validity of proposed method is discussed using a mannequin. Finally, assisting effect of this device is verified from experiments in which subject wears this device actually.

In Japan, low birthrate and aging is progressing rapidly. We need to compensate for the labor shortage, because the working population reduces. As a solution to this problem, the introduction of a robot can be considered. Conventional teaching methods include remote teaching and direct teaching. These teaching methods have problems in terms of difficulty teaching sensibly and safety of the teacher. We extracted the target position / posture of the robot to be taught using motion sensors and verified by simulation before applying the actual machine. As a result, we also found that the accuracy of estimation of trajectory is improved largely by adding some angles to the initial estimated posture along z-axis of which initial posture is estimated by geomagnetic sensor. As a result of the simulation, we found that the hand trajectory estimated from the motion sensor can be applied as the tip trajectory of the manipulator.

In this paper, we present a novel motion guidance method for the human's limbs. In particular, we achieve the motion guidance for the arm by providing single-point vibrotactile feedback in the wrist. In the proposed method, we attempt to produce vibrotactile stimulation in any direction perpendicular to the wrist using a vibrotactile illusion called Phantom Sensation. To achieve this, we built a device with six vibration motors, which is worn around the wrist. We also considered the wrist rotation and control the position of the feedback to produce a consistent direction w.r.t. the global coordinate system. The applicability of the proposed method is demonstrated via motion guidance for the wrist in two-dimensional space.

In recently years, aging society with fewer children are major problem, and it is required that the elderly are independent in order to enhance the quality of life. There are many researches on walking assist suit from this background. Walking is exercise including not only lower body but also upper body movement, but most of these are suits to assist the lower body. Therefore, the purpose of study is to develop walking assist suit focusing on trunk rotation. The control method adopted periodic input control which is effective for periodic motion. And, the Hybrid oscillator is extended,it is possible to change the motion in case of rotating direction switching. In this paper, we describe the design method of the trunk rotation assist device, confirm system effect from experiment. As the result, this system need to consider left and right legs.

It is important to reveal human falling mechanism to prevent falling accident. Many studies have been done to understand the human motion when his/her legs are perturbed during walking. In this paper, to reveal human falling mechanism, the human reaction motion when the constant force is applied to his/her swing leg in forward/backward direction is investigated using a lower-limb power-assist robot. As a result, the magnitude of the force for falling and the feature of trajectory change were found out.

The author proposes a thermal display that can present a virtual thermal sensation to the finger pad using thermal stimuli on the side of the finger. The proposed method could help realize the thermal augmentation of real objects or simplify the design of a haptic display. This study investigates the effect of vibrotactile stimulation to the finger pad in terms of reaction time of the virtual thermal sensation. The results indicate that the vibrotactile stimulation prior to the thermal sensation improves the reaction time. The result demonstrates the utility of the vibrotactile stimulations in developing a thermal display.

In the process of repeatedly pressing and releasing the skin with a needle, fast adapting receptors (FA) in the skin are activated during both pressing and releasing. With this consideration, in our study we hypothesis that, when we are presented the tactile sensation by pulses of electrical current, we will interpret two pulses of stimuli as one time of press-release action. In our previous study, this hypothesis was verified in a certain frequency range. This paper investigates whether this phenomenon occurs also in case of mechanical stimulation, in which the skin is pressed and released with a needle. Result shows that, this phenomenon did not occur when subjects clearly perceive the strength of stimuli.

Humans perceive the surface characteristics of an object through the tactile perception at the fingertip. Our previous study measured the contact area deformation by a camera when forced displacement is given; however, the measurable object was limited to transparent ones. This research develops a new system that can evaluate the deformation of the contact area of a non-transparent object. We replaced a human's fingertip with a transparent fake fingertip and measured the deformation of the contact area when displacement is given. We compared the results of human's fingertip and the results of fake fingertip.

Previously, a tactile display using surface acoustic wave which is a kind of ultrasonic vibration has been developed and can render tactile sensation like roughness. Basic principle is friction reduction induced by the wave and its control. Switching the wave at certain intervals results in vibrations on user's finger surface. To consider realistic rendering, frequency range of the vibration to be presented on the display will be discussed. Aim of this research is to investigate vibration presentation with frequency more than 500 Hz. Amplitude modulation of excited ultrasonic wave was confirmed as frequency response of amplitude modulation. The modulation like 10 kHz was observed. Output vibration as tactile display was also observed with an experimental setup. Mechanical vibration up to 10 kHz was acquired, successfully. Frequency characteristics were also observed.

For operation and experience in mobile devices, vibration feedback is used in addition to audio-visual feedback. In general, however, the vibrators need to drive the entire body of the device which is larger than the actuators, and it is difficult to present a strong vibration stimulus in a mobile environment requiring small size and low energy actuators. Therefore, we propose a device that drives by winding a thin belt with DC motors, and presents vibration by touching the belt with a fingertip. This method makes it possible to present vibration with low energy by vibrating a lightweight belt instead of the entire device body. In this paper, we measured the frequency characteristics of the proposed device and compared the power required for the vibration presentation with the conventional vibrators. As results of experiments, it was confirmed that the proposed device can present vibration with less energy than conventional devices.

Typically, tactile displays are built in the shape of a planar plate. However, devices of such shape are not convenient for systems when the feedback is from prosthesis, as the users frequently do not have use of their hand(s). In this paper, we describe a tactile feedback system, in which the tactile simulator is cylindrical and rotates on the user's upper arm. A tactile sensor measures the friction coefficient of the target surface and out tactile device displays this information in the form of different pressures while the display rotates according to the sensor movement. By calculating how surface details should be converted to pressure, the user can "feel" the surface when rubbing with the prosthesis.

Lower back pain is a major health concern worldwide. One cause of lower back pain is the burden on the lumbar region caused by the handling of heavy objects. To reduce this burden, the Ministry of Health, Labour and Welfare in Japan has recommended “squat lifting.” However, this technique, which supports a large force on lower limbs, is not very popular. Therefore, we aimed to develop a power assist suit for squat lifting. In this paper, we explain the prototype of gastrocnemius-reinforcing mechanism developed in previous research. Next, we discuss the problems of this prototype. Finally, we propose a contraction force transmission mechanism of artificial muscle using tensioner in wire adjustment mechanism using a tensioner as a solution.

Power assistive orthoses and devices are required as means for reducing fatigue. Many assistive devices are “exoskeleton”. External hard structure that they have allow to support our motion powerfully. However, they tends to be hard and heavy. Otherwise, “endoskeleton” can’t support our motion powerfully. However, they are lightweight and flexible. Those characteristics reduce burdens of equipping assistive devices. Thin pneumatic artificial muscle have many advantages, including thin diameter, lightweight and flexible. Those advantages are suitable for endoskeleton. In this paper, we present the design and the prototype of delight suit for lifting of upper limbs. Through subjective experiments, the results show that delight suit support upper limb lifting movement and assist medial deltoid muscle.

The final purpose of this research is to develop “Third Arm” which allows the wearer to perform multiple tasks as we perform daily chores simultaneously. Previous studies on wearable robot arm did not quantify the magnitude of the working space or consider man-machine cooperativeness. The present paper presents a new design approach for the wearable robot arm that evaluates the working space and cooperativeness. To determine the hardware design of the robot arm and securing mechanism, this paper proposes three evaluation indexes: working extensiveness, working cooperativeness and workspace invasiveness. The proposed evaluation indexes were quantitatively assessed according to the calculation of the common domain of the human workspace and robot arm workspace. It was found that the hardware design that secures a vertically articulated robot arm to the shoulder has the highest working property if priority is given to low workspace invasiveness.

This paper aimed to verify the assistive effects of the wearable robotic system “curara” for single-legged assistance of the patients with hemiplegia. In this study, we developed the single-legged curara, which supports walking of the wearer's leg unilaterally based on synchronization control using a neural oscillator. The verification of the effects with the system was implemented through preliminary walking test with a healthy control subject who simulated the physical condition of a hemiplegic patient. The walking of the simulated hemiplegic patients using the single-legged curara showed a significant difference in walking velocity compared to the results when the wearer walked on level ground without wearing the system.