ICR-based Kinematics for Wheeled Skid-Steer Vehicles on Firm Slopes^*

This paper proposes a new kinematic model for wheeled skid-steer vehicles moving with low inertia on firm slopes that is based on the variation of the Instantaneous Center of Rotation (ICR) of its lateral treads. To this end, the ICR-based model for horizontal surfaces, where constant tread ICRs were considered, has been extended with two additional parameters to account for the sliding down phenomenon on inclined terrains that the former is unable to predict. The current pitch and roll angles of the vehicle together with the speeds of the treads are employed to calculate the changing positions of tread ICRs during turnings. This kinematic approach shows promising results when applied to the heavy robotic rover J8 on a slanted surface of smooth concrete.