Conventional and slip steering for multi-wheel planetary rovers

All planetary rovers used up to now and most of those under study are based on wheels for their mobility. The trajectory control of wheeled robots is mostly performed by steering some or all wheels, but the alternative of slip steering seems to be quite promising, in particular for low gravity conditions. The aim of the present paper is to investigate conventional and slip steering using simplified models suitable for rovers with more than two axles, moving at low speed on short radius trajectories. Two examples show that even at low speed the kinematic steering model is unable to predict the trajectory and that slip steering compares favorably with conventional steering.