Many kinds of power assist device have been developed, and are driven with various actuators such as an electric motor, a hydraulic cylinder and so on. By using the exoskeleton, a high generated torque actuator can be introduced. An assist performance of these devices becomes high. On the other hand, a realization of exoskeleton which has the same D.O.F of a human is not easy from considerations about a size and strength of device. In this study, the power assist wear for lower limb is developed. The developed wear is like trousers. A human can be assisted by just wearing trousers on which the pneumatic soft actuators are put. The pneumatic soft actuator has a high power weight ratio, and has a light weight. These features contribute to realize the simple structure which is like clothes. In this paper, the structure of power assist wear is discussed, and the application of power assist wear to assist going up and down stairs are described.

Many kinds of power assist device have been developed, and are driven with various actuators such as an electric motor, a hydraulic cylinder and so on. By using the exoskeleton, a high generated torque actuator can be introduced. An assist performance of these devices becomes high. On the other hand, a realization of exoskeleton which has the same D.O.F of a human is not easy from considerations about a size and strength of device. In this study, the power assist wear for lower limb is developed. The developed wear is like trousers. A human can be assisted by just wearing trousers on which the pneumatic soft actuators are put. The pneumatic soft actuator has a high power weight ratio, and has a light weight. These features contribute to realize the simple structure which is like clothes. In this paper, the structure and characteristics of power assist wear are discussed, and the applications of power assist wear to assist keeping a posture and going up and down stairs are described.

We propose a technology for manipulating the position and orientation of an object in a contactless manner over an extended range. This technology involves multiple ejectors that stream jets of compressed air onto an object from various directions. By regulating the air jet directions and flow rates, the object can be actively "force closured" and its position and orientation can be manipulated freely. As the first step of this research, in this paper, we discuss technological challenges for this method. Next we provide a preliminary investigation with one degree-of-freedom planar experimental system using a continuous and a PWM air jet ejection method. Based on this investigation, we examine problems relating to the use of three air nozzles to control the position of a cylindrical object in two degrees of planar freedom.

We propose a technology for manipulating the position and attitude of an object in a contactless manner over an extended range. This technology involves multiple ejectors that stream jets of compressed air onto an object from various directions. By regulating air jet directions and volumes, the object can be actively “force closured” and its position and attitude can be manipulated freely. As the first step of this research, in this paper, we discuss its potential future applications, and summarize the technological challenges for this technology. Next we provide a preliminary investigation with one degree-of-freedom planar experimental system. Based on this investigation, we examine problems relating to the use of three air nozzles to control the position of a cylindrical object in two degrees of planar freedom.

A target of this study is to rehabilitate an elbow flexing contracture patient caused by a brain infarction and so on. In rehabilitation for the patient, a trainer flexes the patient's elbow by a hand until the patient feels a little pain, and then the trainer keeps the applied force for a while. In this training, it is important that the trainer regulates the applied force depending on the patient's condition. In the developed device, a reaction torque of the slave device is estimated by a disturbance observer. By feeding back the estimated torque to the master device, a master user can feel the reaction torque. In this paper, the structure of the developed device is discussed, and then the control system is described. Finally, the validity of the proposed device is evaluated from the experiments that assume rehabilitation of an elbow.

In this study, in order to realize an assist of independent life for the elderly or people in need of care and relieve a physical burden for care worker, an active support splint driven by pneumatic soft actuator (ASSIST) has been developed. ASSIST consists of a plastic interface with the palm and arm and two rotary-type soft actuators put in both sides of appliance. In this paper, the fundamental characteristics of ASSIST is described, and then the effectiveness of this splint is experimentally discussed. Finally, the operation of ASSIST based on a human intention is described.

In this study, we aim at developing a mechanical device to support humans rehabilitation motion of their wrist joint instead of or to help a physical therapist. Pneumatic parallel manipulator is introduced as the mechanical equipment from a view that pneumatic actuators bring minute force control property owing to the air compressibility and parallel manipulator’s feature of multiple degrees of freedom is suitable for a complex motion of human wrist joint. Impedance control system is introduced to realize several rehabilitation modes. The validity of the proposed system is confirmed through some experiments.

When robots work together with a human or contact with a human body directly in such as a medical welfare field, in order to avoid an accident from crash and so on, a flexibility is required for the robot. The purpose of this study is to realize a safe mechanism for a human-friendly robot. In this paper, the structure and the fundamental characteristics of a pneumatic rubber muscle and soft mechanism are described, and then the structure and the fundamental operation of the developed soft hand are shown. Finally, the shaking hands is discussed as an example of force communication tasks between a robot and a human.

The goal of this study is to develop a mechanical system which display elastic characteristic like stiffness on the surface of human body aiming at applying to palpation simulator. Pneumatic parallel manipulator is employed as a driving mechanism, consequently, it brings capability of minute force displaying property owing to the air compressibility. Compliance control system without using force/moment sensor is constructed by introducing a disturbance observer and a compliance display scheme is proposed. The validity of the proposed scheme is verified experimentally.

The paper proposes an algorithm for object motion estimation. It is assumed that the object motion is composed of primitive motions and the total motion is generated by simply switching these primitive motions. The proposed estimator for visual servoing has two stages: Kalman filter and validation gate. Models of primitive motions are connected and an augmented system is designed. Each primitive motion corresponds to an invariant subset in the state space of the augmented system. The motion switching is generated by a state transition among the state subsets. A Kalman filter is used to predict the object motion on the basis of the augmented system. Switching of actual object motion is detected by the validation gate. The validation gate is implemented by nonlinear least square fitting of the current state onto the nearest state subsets. Real-time experiments of object tracking demonstrate the effectiveness of the proposed estimator.

Stability of feature-based visual servoing controllers proposed so far is local. The initial features far from the reference may converge to features different from the reference or, even worse, they may not converge. In this paper, the stability of feature-based visual servoing is considered by using potential. The stable region is visualized and artificial potential switching is proposed to extend the stable region.

This paper proposes a potential switching scheme that enlarges the stable region of feature-based visual servoing. Relay images that interpolate initial and reference image features are generated by using affine transformation. Artificial potentials defined by the relay images are patched around the reference point of the original potential to enlarge the stable region. Simulations with simplified configuration and experiments on a 6 DOF robot show the validity of the proposed control scheme.

The paper proposes a visual servoing scheme based on object motion estimation. A long term prediction algorithm with multiple motion models is developed. The object position and velocity of a few hundreds of samples ahead is predicted. Thus object tracking without visual information can be achieved during this period. As an example, pick up task of moving object is conducted. The task requires object motion prediction because the hand mounted camera loses the object when the hand approaches the object. Simulations show convergence of prediction. Real-time experiments of picking up a moving object demonstrate the effectiveness of the proposed long term predictor.

One of the most important problems in feature-based visual servoing is the slow sampling rate and the delay of the camera that can make the closed loop system oscillative or unstable easily. In the paper, a linearized observer that estimates the object velocity and updates the visual information with the joint sampling rate is proposed. Stability of the observer-based control system and effectiveness of the observer are verified by experiments on a PUMA 560 robot.

Describes the relationship between the control performance and the number/configuration of the image features in feature-based visual servoing. The performance is evaluated by two ways: accuracy and speed. A quantitive definition of the sensitivity is given and the relationship among the sensitivity, the speed of convergence and the accuracy are discussed by using the image Jacobian. It is proved that these performance indices are increased effectively by using a point with different height. Experiments on Puma 560 are given to show the validity of these performance measures.

This paper presents a visual feedback control scheme for a nonholonomic cart without capabilities for dead reckoning. A camera is mounted on the cart and it observes cues attached on the environment. The dynamics of the cart are transformed into a coordinate system in the image plane. An image-based controller which linearizes the dynamics is proposed. Since the positions of the cues in the image plane are controlled directly, possibility of missing cues is reduced considerably. Simulations are carried out to evaluate the validity of the proposed scheme. Experiments on a radio controlled car with a CCD camera are also given.

Yo-yo is a toy made of two thick circular pieces of wood, plastic, etc., connected with a short axle that can be made to run up and down, by moving a string tied to it. Humans can play with a yo-yo without difficulty. However, developing a robot system that can play with a yo-yo presents a significant challenge to controller design, because the dynamics of the yo-yo are difficult to model precisely. Moreover, since the dynamics are not continuous and there are integral-type constraints on the hand trajectory, conventional continuous time feedback control theory does not work well. This paper present a model and a control scheme for robotic yo-yo with visual feedback. Experiments on a PUMA 560 are carried out to evaluate the validity of the discrete dime formulation and the controller design.

The goal of this paper is to attain a robust positioning control of a pneumatic driving system. A positioning control system positively focusing on the pressure control is investigated from the view that the pressure control is indispensable for improvement of control performances. A disturbance observer is employed to improve the pressure response and compensate the influence of friction force and parameter change. Consequently the improvements of robustness against payload and of positioning accuracy have been attained.