Yasuhiko Ishigure

Five-Fingered Haptic Interface Robot: HIRO III

This paper presents the design and characteristics of a five-fingered haptic interface robot: HIRO III. The aim of the paper is to provide a high-precision force representation at the five human fingertips. HIRO III consists of a 15-degree-of-freedom (DOF) haptic hand, a 6 DOF interface arm and a control system. The haptic interface, which consists of a robot arm and hand, can be used in a large workspace and can provide multipoint contact between the user and a virtual environment. However, the following problems peculiar to a multi-DOF robot have resulted: a backlash, a large amount of friction, many motors, and many sensors. In order to solve these problems, a new mechanism and a wire-saving control system have been designed and developed. Furthermore, experiments in both free space and constraint space have been carried out. In comparison with the previous HIRO, the force errors in free space and in constraint space have been reduced to 30% and 57%, respectively. These results show a high-precision force representation and the great potential of HIRO III.

A design of fine motion assist equipment for disabled hand in robotic rehabilitation system

This paper reports a newly designed system intended to aid in hand rehabilitation. The motion assistance equipment consists of three parts: mechanisms for the fingers and thumb, a base of these mechanisms, and a motion assistance mechanism for the wrist. The structure of each mechanism is designed to achieve independent, fine motion assistance, especially, for the individual fingers. First, the features of each mechanism in the equipment are explained. Next, the control systems are introduced, which are constructed to realize a self-motion control strategy (i.e., the motion is controlled by its user). Using this control system, the transient response and steady state characteristics of the motion assistance mechanisms for the thumb are evaluated. Consequently, the possibility of practical application is found in regard to some improved points.

Five-fingered haptic interface robot: HIRO III

This paper presents the design and characteristics of a five-fingered haptic interface robot named HIRO III. The aim of the development of HIRO III is to provide a high-precision three-directional force at the five human fingertips. HIRO III consists of a 15-degrees-of-freedom (DOF) haptic hand, a 6-DOF interface arm, and a control system. The haptic interface, which consists of a robot arm and hand, can be used in a large workspace and can provide multipoint contact between the user and a virtual environment. However, the following problems peculiar to a multi-DOF robot have arisen: a large amount of friction, a backlash, and the presence of many wires for many motors and sensors. To solve these problems, a new mechanism and a wire-saving control system have been designed and developed. Furthermore, several experiments have been carried out to investigate the performance of HIRO III. These results show the high-precision force display and great potential of HIRO III.

Development of virtual reality exercise of hand motion assist robot for rehabilitation therapy by patient self-motion control

This paper presents a virtual reality-enhanced hand rehabilitation support system with a symmetric master-slave motion assistant for independent rehabilitation therapies. Our aim is to provide fine motion exercise for a hand and fingers, which allows the impaired hand of a patient to be driven by his or her healthy hand on the opposite side. Since most disabilities caused by cerebral vascular accidents or bone fractures are hemiplegic, we adopted a symmetric master-slave motion assistant system in which the impaired hand is driven by the healthy hand on the opposite side. A VR environment displaying an effective exercise was created in consideration of systems characteristic. To verify the effectiveness of this system, a clinical test was executed by applying to six patients.

A pruning robot with a power-saving chainsaw drive

We present a novel pruning robot that uses self-weight and a power-saving chainsaw drive. The pruning robot consists of a climbing up-and-down mechanism, a chainsaw mechanism, and a controller. The climbing up-and-down mechanism has four active wheels equipped with a steering mechanism and a two-DOF posture adjustment mechanism to keep the pruning robot in a horizontal posture. The robot can stay on a tree without energy consumption by using its own weight. The chainsaw mechanism consists of a chainsaw and a two-DOF pose adjustment mechanism, which has a liner joint to maintain a specified distance between the tree surface and chainsaw, and a tilt joint to keep the chainsaw in a specified posture against the tree surface. In the chainsaw power-saving drive, there are two modes of a high input and a low input, and its switching is executed based on the disturbance estimation. It is shown experimentally that the developed robot can do pruning work with low power consumption.

Development of robot hand for therapist education/training on rehabilitation

Students studying to become therapists have few opportunities for repeated training for the rehabilitation of contracture joints. This paper proposes the concept of a robot hand system for repeated rehabilitation training. A novel robot hand and artificial skin are developed in collaboration with doctors and therapists. Development of the robot hand is based on new design concepts aimed at imitating a human hand with a disability. The joint torque of a disabled person can be estimated by distributed tactile sensors. A model of contracture joints with tendon adhesion is introduced. The robot hand in imitation of contracture joints is governed by the force control based on torque control. The effectiveness of the proposed method is demonstrated experimentally.

A hand rehabilitation support system with improvements based on clinical practices

Abstract We are aiming at developing a hand rehabilitation support system that provides a rehabilitation environment where patients can conduct enjoyable trainings by themselves as much as they want. First of all, the feature of this rehabilitation support system is explained with its design concept. Next, problems that came into the open by the verification test in the clinical practice are described. Two main problems are: (1) the structure of the thumb opposability assistance mechanism sometimes avoids patients from safely attaching their affected hand to the motion assistance device, (2) the connection between the affected hand and the motion assistance device requires much time and often disconnected. For the first point, we improved it by designing new thumb motion assistance mechanism with the double parallel-link structure. For the second one, the attaching method using magnetic force is introduced. The effects of these improvements are reported with experimental results.

Development and experimental study of a novel pruning robot

This article presents the development of a timberjack-like pruning robot. The climbing principal is an imitation of the climbing approach of timberjacks in Japan. The robot’s main features include having its center of mass outside the tree, and an innovative climbing strategy fusing straight and spiral climbs. This novel design brings both lightweight and high climbing speed features to the pruning robot. We report our progress in developing the robot, focusing on straight climbing, behavior on uneven surfaces, and pruning.

A haptic interface robotic measurement system for breast engorgement

Breast engorgement, a potentially harmful condition among new mothers, is difficult to quantify objectively. We propose a system that can precisely quantify breast stiffness as an estimate of engorgement. The table-top system uses a multi-fingered haptic interface robotic hand that can simultaneously measure fingertip force and position with high precision at multiple points. The system includes a support base, power supply, UDP/IP connection, and software for control, data entry and data analysis. The manipulation of the haptic hand is accomplished automatically. We tested the system with a breast exam simulator and found that the stiffness data obtained by the system can be used to objectively estimate breast engorgement.

Parallel controller construction for a multi-DOF hand rehabilitation equipment

This paper describes the development of a hand rehabilitation system for stroke patients. Our aim is to provide fine motion exercise for a hand and fingers. Thus, a hand rehabilitation device that assists patients’ finger movements was developed. Because this device has 18 degrees of freedom of motion, it is difficult for disabled patients to use it by themselves. Therefore, an appropriate control strategy and control system are required to allow its safe and effective use. In light of this requirement, a control system was constructed which is comprised of four separated controllers. This paper presents the structure of the control system and introduces the control protocols used in our hand rehabilitation system.