Trilateral Predictor-Mediated Teleoperation of a Wheeled Mobile Robot With Slippage

Abstract

With the widespread use of wheeled mobile robots (WMR) in various applications, new challenges have emerged in terms of designing its teleoperation system. One of such challenges is caused by wheel slippage and another is due to the strict need for ensuring WMR safety. This letter proposes a new trilateral teleoperation scheme for haptic teleoperation control of a WMR (slave) with longitudinal slippage. In this teleoperation system, a virtual model (predictor) of the slave WMR is utilized at the master site to guide the human operator to issue more effective commands and, by mediating between the master and the slave WMR, ensure that unsafe maneuvers are not performed by the WMR. Besides compensation for the WMR/terrain's nonpassivity caused by the slippage, a shared control is proposed for the system. Theoretically, the system's stability is shown via its passivity and it is shown that the force felt by the human operator is approximately equal to the forces applied by the environment of the predictor plus that of the slave robot, which is a satisfactory performance outcome. Experiments of the proposed WMR teleoperation system demonstrate that it results in stable trilateral teleoperation with a satisfactory tracking performance. The predictor at the master site is shown to compensate for lack of precise information about the slave robot.