Abstract: During planetary exploration, the rover demands the capability of terrain characteristic estimation for timely adjustment of control strategies to quickly adapt to terrain changes. For the parameter-coupled wheel-terrain interaction model with complex forms, the Sobol analysis method is adopted to quantitatively analyze the sensitivity of terrain bearing and shearing characteristic parameters in the model, respectively. In consequence, the sinkage exponent and internal fraction angle are selected as the dominant parameters reflecting significant changes in the terrain bearing and shearing characteristics. Based on the mechanics equilibrium equation of wheel-terrain interaction, the analytical model of the dominant parameters is further derived by simplifying the stress distribution formula. By fixing the non-dominant parameters with typical values, the system state parameters and the filtering process are used to realize dominant parameter estimation of the terrain mechanical characteristics. The results show that the proposed analytical model of the dominant terrain mechanical parameters and the corresponding estimation method can quickly follow the change of terrain properties. The average relative error of the sinkage exponent estimation is 2.8% and that of the internal friction angle estimation is smaller than 3%. The estimation results can accurately predict the traction force of the wheels as well as provide necessary information for real-time traction control.

Key words: sensitivity analysis, parameter estimation, wheel-terrain interaction, dominant parameters, analytical model