Tetsuya Mouri

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.

Design and Control of Five-Fingered Haptic Interface Opposite to Human Hand

This paper presents the design and control of a newly developed five-fingered haptic interface robot named HIRO II. The developed haptic interface can present force and tactile feeling to the five fingertips of the human hand. Its mechanism consists of a 6 degree of freedom (DOF) arm and a 15 DOF hand. The interface is placed opposite the human hand, which ensures safety and freedom of movement, but this arrangement leads to difficulty in designing and controlling the haptic interface, which should accurately track the fingertip positions of the operator. A design concept and optimum haptic finger layout, which maximizes the design performance index is presented. The design performance index consists of the product space between the operators finger and the hapic finger, and the opposability of the thumb and fingers. Moreover, in order to reduce the feeling of uneasiness in the operator, a mixed control method consisting of a finger-force control and an arm position control intended to maximize the control performance index, which consists of the hand manipulability measure and the norm of the arm-joint angle vector is proposed. The experimental results demonstrate the high potential of the multifingered haptic interface robot HIRO II+ utilizing the mixed control method.

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.

Developments of new anthropomorphic robot hand and its master slave system

This paper presents a newly developed anthropomorphic robot hand called KH Hand type S, which has high potential of dexterous manipulation and displaying hand shape, and its master slave system using the bilateral controller for five-fingers robot hand. The robot hand is improved by reducing the weight, the backlash of transmission, and the friction between gears by using elastic body. Expression of Japanese finger alphabet is shown. In order to demonstrate the dexterous grasping and manipulating an object, the experiment of peg-in-hole task controlled by bilateral controller is shown. These results denote that the KH Hand type S has a high potential to perform dexterous object manipulation like the human hand.

Control of multi-fingered haptic interface opposite to human hand

Haptic interfaces, which present force and tactile feeling at human fingertips, are utilized in the aria of tele-manipulation of robots, simulation and design in virtual reality environments, educational training, and so on. The haptic interface is demanded to be safe, to work in wide operation space, and to present not only force at contact points but also weight feeling of virtual objects, to have no oppressive feeling when it is attached to humans, and to have no weight feeling of itself. This paper presents a control architecture of the developed multi-fingered haptic interface, named Gifu Haptic Interface. The haptic interface was designed to be completely safe and to be similar to the human upper limb in shape and motion ability. The interface is placed opposed to the human hand, which brings safety and no oppressive feeling, but causes difficulty in controlling the haptic interface because it should follow the hand poses of the operator. Two control methods of the haptic fingers are tested and two approaches to oppose the interface hand to the human hand are studied. A computer graphics simulation and experiments are also presented.

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.

Review of Gifu Hand and Its Application

In this paper, an attempt at summarizing the state of the art in the field of robot hands is described. The survey is focused on the Gifu Hand series and its application. To create a standard robot hand that is used to study grasping and dexterous manipulation, the Gifu Hand has been developed. Authors study not only a mechanical structure of the robot hand but also control methods for dexterous and autonomous work that human hands perform. The robotics technology is applied to a haptic interface and to a hand rehabilitation systems and medical care.

Identification of contact conditions from contaminated data of contact moment

When a grasped object is in contact with external environment, it is required to identify contact conditions prior to performing the assembly tasks. This paper discusses a method for identification of contact conditions from the information of force sensor equipped with the robot hand. This paper treats the practical case where sensing data are contaminated with noise. We propose an efficient and analytical algorithm for identifying contact conditions by using an active force sensing method. The algorithm can identify not only contact position and contact force, but also contact type such as soft finger contact type, line contact type, and plane contact type. These contact types are characterized by a standard deviation of contact moments. The contact position is estimated by a least-squares method. The contact moment is then estimated from noisy observations and its eigenvalues are analyzed. The contact type can be judged by the eigenvalues of estimated contact moment. The effectiveness of the algorithm is demonstrated by simulations.

Virtual teaching based on hand manipulability for multi-fingered robots

A virtual robot teaching that consists of human demonstration and motion-intention analysis in a virtual reality environment is an advanced technology of automatic programming for multi-fingered robots. For the virtual hand model displayed on-screen, a human-hand model is better than a robot-hand model in terms of teaching time and a stable manipulation of virtual object. However, it may occurs that a robot cannot grasp an object at a teaching position and orientation of the robot hand because the geometrical size and motional function of the robot hand is not the same as that of human hand. To solve this problem, we propose a virtual teaching based on hand manipulability, in which a position and orientation of the robot hand is determined so as to maximize a manipulability of the robot hand on the condition that the robot grasps the object at the teaching contact points on the object. Experimental results of a pick-and-place task are shown to demonstrate the effectiveness of the proposed method.

Multi-Fingered Haptic Interface Robot Handling Plural Tool Devices

Tool-type haptic interfaces such as scissors are used to present force feeling for surgical training in virtual reality environment. Presentation of force feelings of plural tools needs to prepare many single tool-type haptic interfaces. This paper proposes newly conceptual idea for plural tool-type haptic interfaces. The proposed system consists of single tool-type haptic devices and a multi-fingered haptic interface. The system has a greater potential for the force feelings of plural tool devices than does a single tool-type interface in the view of work space, removable equipment, force control, small dimensions, and simple tool-type device. Tool-type devices, which are scissors, injector, and knife, are developed to present reactive feeling. Experimental results of cutting simulation are shown to demonstrate the effectiveness of proposed system