Kinematic Teleoperation of Wheeled Mobile Robot With Slippage Compensation on Soft Terrains

The wheeled mobile robot (WMR) is widely employed in many industrial fields, and more new control difficulties appear when the WMR works on soft terrains (e.g., Lunar exploration), one of which is induced by wheel slippage. In this paper, a new approach for the haptic teleoperation of a differential WMR coupling with wheel slippage on soft terrains is proposed. In the proposed teleoperator, the linear/angular velocities of the slave WMR are directly mapped with the master robot's positions. The command-tracking errors and the non-passivity at the slave WMR site induced by the wheel slippage are compensated by the proposed feedforward controllers for each wheel based on the online estimated slippage. The stability of the teleoperation system is guaranteed by the passivity theory while the environment termination is proved to be passive with the proposed feedforward controllers. The experiments validate that the proposed teleoperator is stable while the command-tracking performance of the slave WMR is obviously improved on soft terrains.