Fuzzy bilateral control of time delayed nonlinear tele-robotic system in unknown environments through state convergence

State convergence belongs to the class of non-passive schemes and offers a complete framework for bilaterally controlling the tele-robotic systems. Contrary to many other schemes, it allows modeling the tele-robotic systems on state space and provides guaranteed performance of their closed loop behavior. In this study, we have used the state convergence scheme to design a bilateral controller for a nonlinear tele-robotic system where the slave is working in an unknown environment. The nonlinear tele-robotic system is first approximated by a Takagi-Sugeno (TS) fuzzy model. A fuzzy control law is then employed to derive the design conditions following the method of state convergence in order to ensure that the slave follows the master and the desired dynamic behavior of the tele-robotic system is achieved. Further, the existing state convergence based linear bilateral controller is found to be a special case of the proposed state convergence based fuzzy bilateral controller. A one-degree-of-freedom (DoF) nonlinear tele-robotic system is finally simulated in MATLAB/Simulink environment to show the effectiveness of the proposed approach.