バイモルフ型圧電素子で駆動されるソフトハンドリング・グリッパ : 第2報, 把持動作制御用コントローラの設計

This paper is a study on the hybrid force/position control of a two-fingered miniature gripper driven by piezoelectric bimorph cells. The system is composed of two flexible cantilevers and a compact force sensor attached to the tip of one finger. Control action is applied by two piezoelectric bimorph strips placed at the base of each finger. Both the classical PID control and the H∞ control algorithm are examined for the control problem in which the gripper is commanded to grasp an object with a time-constant force 0.01 N at a prescribed fingertip position. Furthermore, a new PID controller based on the H∞ theory is proposed and applied to the control of the gripper. It is found that the modified PID controller is simple and shows good robustness for controlling and driving the gripper.