Slip-based Traction Control of a Planetary Rover

This paper investigates slip-based traction control of a planetary rover that travels over natural rough terrain. Special attention is made on tire-soil traction mechanics and articulated body dynamics. Experiments are carried out with a rover test bed to understand the physical behavior of tire-soil interaction and, thereby, a traction model is investigated using the tire slip ratio as a state variable. Specific soil and tire parameters are identified from the experimental data. A slip-based control method is proposed and tested. The proposed method keeps the slip ratio within a small value and limits excessive tire velocity or force, so that the rover can successfully traverse over sandy obstacles avoiding the situation that spinning wheels are stuck in the loose soil.