Adaptive global sliding mode control for multilateral teleoperation systems with varying-time delay

In this paper, we suggest an adaptive control for a multilateral teleoperation system (MTS) with an unknown upper limit on the system uncertainty (SU) and varying-time delay (VTD). A novel adaptive global sliding mode (AGSMC) has been addressed, which guarantees the elimination of the reaching phase and forces the tracking error to reach the sliding surface (SS) from the beginning. Moreover, the adaptive tuning law has been addressed in order to deal with the undetermined upper limit of the SU. The convergence and stability analysis of the proposed methods is verified by the Lyapunov stability theory. The simulation is carried out on 1 master, 1 leader, and 3 followers teleoperation system is developed to show the effectiveness of the developed control.