Lunar rover wheel-terrain interaction model for climbing-up-slope based on terramechanics

The lunar rover terramechanics model for climbing-up-slope plays important roles in mechanical design, obstacle-overcoming performance evaluation, control, simulation, etc. Experiments are performed to test the wheel performances of climbing slopes using the wheel-terrain interaction testing system developed for lunar rover. A climbing-upslope model for wheel-terrain interaction is derived according to the conventional wheel-terrain stress distribution models and experimental data. The influence on stress distribution of shallow layer soil caused by slope angle is also considered. An empirical formula for calculating the sinkage exponent as a function of the slip ratio is proposed, in order to reflect the sinkage caused by the soil compaction, scrape, lateral flow, and so on. The model for calculating concentrated force/torque is obtained by integrating the stress distribution formula, which is then verified by experimental data and flexible slope-climbing simulation platform developed secondarily with ADAMS. If the slope is 16±, load is 100 N, and slip ratio increases from 0 to 0.6, the relative errors of predicting normal force, drawbar pull and driving torque between calculation values and experimental data are less than 10%. The model can predict wheel-terrain interaction mechanics effectively for a rover while climbing up slopes.