Fuzzy model-based design of a transparent controller for a time delayed bilateral teleoperation system through state convergence

Abstract

Transparency optimized state convergence scheme is a simple, elegant and easy to design bilateral control algorithm for nth-order linear teleoperation systems modeled on state space. It requires the solution of 3n+2 design equations to determine the control gains when the time delay in the communication channel is small. The controller thus obtained allows the slave system to follow the master system’s motion in a desired dynamic way while providing the human operator with a high degree of environment’s feeling during the steady state operation. This paper employs the transparency optimized state convergence scheme to design a bilateral controller for a class of nonlinear teleoperation systems which can be approximated by Takagi-Sugeno (TS) fuzzy models. To close the feedback loop around master and slave systems, a suitable parallel distributed compensation (PDC) type TS fuzzy controller is selected which allows to use the state convergence procedure in a true sense. In this way, all the benefits of the state convergence scheme have been kept intact while extending its applicability to nonlinear teleoperation systems at the same time. Further, the proposed fuzzy state convergence controller is more general as the existing linear state convergence controller can be derived from it. MATLAB simulations on a one-degree-of-freedom (DoF) nonlinear teleoperation system are included to show the efficacy of the proposed fuzzy transparent state convergence controller.