State and Disturbance Estimation Based on Internal Model Control Structure and Its Application to Sensorless Grasping Control

A new controller scheme based on the IMC design structure is proposed in this paper. Due to using an inverse system or an approximate inverse system for the IMC structure, the order of the controller leads the high order, meanwhile the high order controller is not practical in implementation. This paper is concerned with the problem of reducing a high order controller to a reduced order one. The disturbance estimation property of the closed loop system is also discussed. The proposed controller scheme is applied to a prototype robotic hand that can hold an object with suitable grasping force without force sensor. The effectiveness of the proposed controller scheme is confirmed by experiments.