State Convergence Based Control of Teleoperation Systems

Abstract

State convergence scheme was proposed in 2004 to overcome the modeling issues and the difficulty in assigning the desired dynamic behavior to the tele-operation systems. It was originally proposed for linear master/slave devices which communicate over a communication channel offering a fixed small time delay. Later, the scheme was extended to cover the cases of non-linear tele-operation systems with a variable time delay in the communication channel using the adaptive control theory, Lyapunov functions and the feedback linearization techniques. However, the use of this scheme for the control of non-linear tele-operation systems which can be approximated by a class of Takagi-Sugeno fuzzy (TS) models has not yet been explored. Also, the scheme is only applicable to teleoperation systems where single master can control a single slave device which limits its usage in situations where more than one master and/or slave devices are involved to perform a task. Thus the objective of the present study is to first employ the state convergence scheme to control a nonlinear teleoperation system represented by TS fuzzy models and then to extend this scheme for the case of teleoperation systems having more than one master and/or slave devices. To achieve the first objective, a parallel distributed compensation (PDC) type control law is introduced to close the feedback loop around the master and slave devices and method of state convergence is applied to solve for the control gains. The second objective is achieved by proposing an alpha modified version of the standard state convergence scheme which provides a framework to combine the commands from all the master units to affect the slave units. The proposed works are validated afterwards in MATLAB/Simulink environment using single and multi-degree-of-freedom (DoF) manipulators.