A sliding mode-based impedance control for bilateral teleoperation under time delay

Several control strategies have been proposed to deal with time delay, parametric uncertainties and nonlinearities for bilateral teleoperation. Furthermore, published works had shown that sliding mode control is a viable option to deal with parametric uncertainty and hard nonlinearities. In this paper, an impedance control based on sliding mode techniques is presented, to guarantee robust tracking under unknown constant time delay. Furthermore, in order to implement the proposed impedance controller, it is necessary to know the velocity and acceleration of the slave system, then to overcome this problem, i.e the estimation in teleoperation in presence the unknown time-delays in the communication channel, a nonlinear observer designed via the super twisting algorithm is presented in order to estimate velocity and acceleration. Simulation results are presented and discussed, which reveal the effectiveness of the proposed observer with the sliding mode control.