Teleoperation of wheeled mobile robots subject to longitudinal slipping and lateral sliding by time-domain passivity controller

Abstract

Wheeled mobile robot (WMR)-based exploration on soft terrains has created new difficulties for its tele-control system. A critical problem is that wheel-terrain contact areas may induce both longitudinal slipping and lateral sliding. In this paper, a new approach for tele-driving a WMR that addresses the difficulties simultaneously induced by both longitudinal slipping and lateral sliding is presented. In the augmented coordination between the master and slave site, the translational and angular velocities of the slave WMR were modified by the wheel sliding angle. Moreover, they were separately coordinated with the positions of the master haptic interface. To improve the command-tracking performance with the augmented coordination, the teleoperator was designed with feedforward of the sliding angle. To compensate for the non-passivity induced by longitudinal slipping and lateral sliding, a time-domain passivity controller also is proposed. The stability and transparency of the proposed approach were analyzed based on the passivity theory. Numerical experiments validate that this proposed approach can effectively improve the teleoperation performance of human operators for the WMR on soft terrains.