Slippage-Dependent Teleoperation of Wheeled Mobile Robots on Soft Terrains

The slippage appears on soft terrains for wheeled mobile robots (WMR), and generates a motion deviation at the contact area, which can induce poor command-tracking performance (meaning difference between WMR's actual motion and operator's command) and instability for its teleoperation. Our previous studies have presented some approaches to conservatively ensure the system stability, and a new slippage-dependent teleoperator is proposed herein to further improve the teleoperation performance. The kinematic model is augmented in the presence of slippage, and slippage-induced unstable elements are revealed by passivity analysis. To compensate for the activity and improve the command-tracking performance induced by slippage, the combination of a slippage-dependent forward feedback controller and a traditional position-error-based controller is proposed. Experiments validate that the proposed method can yield a stable system with good command-tracking performance and force transparency compared with previous studies.