Assist control for positioning task by flexible master-slave system

Abstract

This paper presents a new assist control method for positioning tasks by using a master-slave system having the elasticity on the slave arm. When the operator performs the positioning task with the flexible master-slave system, the remote operation becomes too difficult owing to the elastic vibration of the slave arm. In order to reduce the operator's load and to assist the operation, we design a new assist control method on the basis of the following design policies: (i) we imitate skills of skilled operators and (ii) we permit a slight autonomic movement of the slave arm. For these policies, the strain feedback is introduced to the conventional bilateral control method. This implies the strain signal at the root of the slave arm is fed back to both the master and slave inputs. We examine the stability of the closed-loop system with the human model and the proposed control system. Then we evaluate the maneuverability of the proposed assist control method on the basis of the task success time and the operator's feeling by the SD method. Also we evaluate it by applying the principle component analysis to the results of the SD method. These evaluation results show an improvement of the maneuverability and confirm the effectiveness of the proposed assist control method.