Sliding-mode-based impedance controller for bilateral teleoperation under varying time-delay

In the previous works, we have proposed new control schemes based on the sliding mode control and impedance control in order to cope with varying time delays. However, the previous controller needs local compliance to reduce contact forces between the slave and environment. In this paper, we modify the previous one to have a sliding surface for the slave include an impedance model. Since the nonlinear gain of the sliding controller is independent of the time delay as in the previous proposed controllers, it is not necessary to measure or estimate the time delay to implement the controller. The validity of the proposed control scheme is demonstrated by experiments with a 1-DOF master/slave system connected through the Internet.