Sliding-mode controller for bilateral teleoperation with varying time delay

Bilateral teleoperation systems connected to computer networks, such as Internet, have to deal with varying communication time delay. The entire system is easy to become unstable due to irregular time delay. In this paper, we design a sliding-mode controller for the slave and an impedance controller for the master. We propose a modified sliding-mode controller, in which the nonlinear gain can be set independently of the time delay variation. The proposed controller effectively compensates the effects of the varying time delay which deteriorates the performance of the regular sliding-mode controller. We illustrate the validity of the proposed controller using simulations with 1-DOF master/slave bilateral teleoperation system