Longitudinal skid model for wheels of planetary exploration rovers based on terramechanics

Planetary exploration rovers are playing important roles in space exploration, and the study of wheel–soil interaction mechanics is of substantial importance for a planetary exploration rover to successfully complete its exploration mission. Skid terramechanics is an important part of wheel–soil interaction mechanics, but has been rarely studied. This paper presents a parametric study of the wheel performance under skid conditions and an improved new semi-empirical model, the unknown parameters of which could be estimated with cyclic iteration optimization method. Longitudinal skid experiments are performed using a representative cylindrical wheel on a single-wheel testbed. Experimental results are used to learn longitudinal skid terramechanics. It is assumed in this paper that there exists a misalignment between the angular position of the maximum radial stress and the angular position of the transition point of tangential stress, and an improved quadratic model is proposed for calculating the sinkage exponent. The parameters of mechanical property of planetary soil simulant are measured by pressure-sinkage experiments and shearing experiments. A longitudinal skid terramechanics model is established for planetary rovers’ wheels. According to the comparison between the experimental results and simulation results, we find that the performance of rover wheels can be accurately predicted using the proposed model.