Cooperative Impedance Control of a Finger-Manipulator System in Consideration of Manipulability

Abstract

In the previous study, a cooperative control algorithm was proposed for a finger-arm robot composed of a 3 DOF finger robot and a 6 DOF arm robot. However, free movement of the robot was only discused in the previous study. This paper describes a control method for a finger-arm robot in order to simulataneously achieve the manipulability control and the impedance control in a three-dimensional space. Firstly, the control loops of the passive impedance control and the active impedance control are developed by using the previous heuristic method, and the experiments are made to examine their features and effects. Secondly, the algorithm of the steepest ascent method to control the manipulability of the finger robot is also proposed for the impedance control. The effectiveness of the proposed method was shown in the optimization process of the manipulability. The proposed method gives advantages of enlarging the impedance space, singularity avoidance and avoidance of unexpected obstacles.