A Design of Digital Controller Using Disturbance Observer for Bilateral Master-Slave Manipulator Systems

Abstract

This paper presents a digital control architecture of bilateral master-slave manipulator systems which can realize high-fidelity telemanipulation.
So far, we proposed a digital control algorithm for bilateral master-slave manipulator systems which maintains system stability even though the inertial parameters of the operator and the task object are changed. This algorithm was developed based on linearization using inverse dynamics, however, obtaining precise manipulator dynamic models is not easy.
In order to realize high-fidelity telemanipulation in actual manipulator systems, it is necessary to achieve high-performance dynamic control of the manipulator and to incorporate force and acceleration signal sensors. So, we installe a disturbance observer in front of the master-slave controller in each manipulator to compensate for error dynamics from a model system, such as friction at manipulator joints. As a result, we can design a master-slave control system based on the model manipulator system and that helps to estimate the acceleration signals of the manipulator end-point using model manipulator dynamics, where previously acceleration sensors were required for high performance bilateral control.
In this paper, we first design a double structured digital controller consisting of disturbance observers and a master-slave controller. Secondly, stability of the designed disturbance observer is analyzed for single degree-of-freedom case. Finally, the validity of the proposed control method is confirmed experimentally for a single degree-of-freedom master-slave system.