Teleoperation of Wheeled Mobile Robot With Dynamic Longitudinal Slippage

The increasing demand for a wheeled mobile robot (WMR) in many special fields (e.g., planetary exploration) has generated new difficulties, one of which is caused by the wheel longitudinal slippage on soft terrains. Compared with the general teleoperation under wheel pure rolling (no slippage), the introduction of wheel slippage creates new issues that potentially cause WMR instability. A new bilateral teleoperator for WMR coupling with dynamic longitudinal slippage is presented in this article. The traditional dynamic model is augmented in the presence of wheel slippage, whereas the slippage-induced unstable elements are determined through passivity analysis. To compensate for the active energy at the slave site, this article proposes a conservative slippage-dependent local controller without online estimation for wheel slippage. The teleoperator is then designed by guaranteeing the passivity of the entire teleoperation system. Experiments validate that the proposed methods can result in a stable system on soft terrains with good performance.