Semi-autonomous bilateral teleoperation of six-wheeled mobile robot on soft terrains

With the increasing use of multi-wheeled mobile robots in various fields, a few new challenges pertaining to the design of the teleoperation system of such robots have emerged. This paper proposes a new two-level architecture for haptic teleoperation of a six-wheeled mobile robot (SWMR) with a rocker-bogie chassis on soft terrains. In teleoperation, the linear and angular velocities of the SWMR base follow the master robot's positions. At the slave SWMR level, local compensation controllers are designed for the driving motors and the steering motors to track the desired velocities of the base and eliminate the negative influence of wheel slippage. Command-tracking errors caused by wheel slippage at environment termination (ET) are conveyed to the human operator through haptic (force) feedback. By guaranteeing the passivity of ET, the stability conditions of the teleoperation system are constrained by the Llewellyn criterion. Experiments conducted using the proposed controllers demonstrated that the tracking errors in the commands sent to the slave robot are effectively compensated for, and the controllers achieve stable teleoperation with satisfactory tracking performance.