Takahiro Endo

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.

Simple Boundary Cooperative Control of Two One-Link Flexible Arms for Grasping

This paper considers a grasping task by means of two one-link flexible arms. To accomplish this task, we propose a simple boundary cooperative control based on a dynamic model, which consists of partial differential equations (PDEs) and ordinary differential equations (ODEs) subject to geometric constraints. Since the data which is needed for the implementation of the controller can be obtained by a strain gauge and a rotary encoder, it is easy to implement it. The asymptotic stability of a closed-loop system and the exponential stability of the system under some conditions are studied.

Augmented Stable Fuzzy Control for Flexible Robotic Arm Using LMI Approach and Neuro-Fuzzy State Space Modeling

Designing the control strategy for a flexible robotic arm has long been considered a complex problem as it requires stabilizing the vibration simultaneously with the primary objective of position control. A stable state-feedback fuzzy controller is proposed here for such a flexible arm. The controller is designed on the basis of a neuro-fuzzy state-space model that is successfully trained using the experimental data acquired from a real robotic arm. The complex problem of solving stability conditions is taken care of by recasting them in the form of linear matrix inequalities and then solving them using a popular interior-point-based method. This asymptotically stable fuzzy controller is further augmented to provide enhanced transient performance along with maintaining the excellent steady-state performance shown by the stable control strategy. The controller hence designed has been successfully implemented for a real robotic arm to operate over a long angular range of 180 with several payload conditions and, for situations where the system is operated for a long range and with a large variation in payload conditions, it could successfully outperform the recently proposed proportional derivative and strain controller.

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.

Force control and exponential stabilisation of one-link flexible arm

In this paper, we discuss a force control problem for a constrained one-link flexible arm. To solve the force control problem, we propose a simple boundary feedback controller that consists of the bending moment at the root of the flexible arm and its time derivative. The striking point is that information about the force and the rotational angle of the motor is not necessary for the implementation of the controller, and thus we do not need a force sensor or encoder in the construction of the controller. The exponential stability of the closed-loop system is then provided using the energy multiplier method. We describe several experiments carried out to investigate the performance of the proposed controller.

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

Human Perception Test of Discontinuous Force and a Trial of Skill Transfer Using a Five-Fingered Haptic Interface

In the transferring of expert skills, it takes a great deal of time and effort for beginners to obtain new skills, and it is difficult to teach the skills by using only words. For those reasons, a skill transfer system that uses virtual reality (VR) and a haptic interface technique is very attractive. In this study, we investigated the human perception of fingertip force with respect to the following changes: (1) the spatial change of the presented force, and (2) the change of the time to present the force. Based on the results of the perception experiments, we considered the skill transfer to a persons five fingers by using a five-fingered haptic interface robot.

Finger pad force display for hand haptic interface

This paper presents a finger pad force display device for a hand haptic interface for use in a virtual reality environment. The haptic interface consists of finger pad force display devices and a 3D fingertip haptic display device. The finger pad force display device is closed-loop controlled by the use of a tactile sensor. The design concept, the specifications of the finger pad force display and an experimental comparison between open-loop control and closed-loop control in the case of object touching in a virtual reality are presented.

Hand haptic interface incorporating 1D finger pad and 3D fingertip force display devices

The present paper introduces a hand haptic interface for use in palpation training in a virtual reality environment. The developed hand haptic interface consists of novel finger pad force display devices and a 3D fingertip haptic display device. The total number of displayed points is 14. The finger pad force display devices are open-loop controlled by a time interval control. The design concept, the specifications of the finger pad force display, and the results of experimental evaluations of the hand haptic interface are presented.