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 per-formances of climbing slopes using the wheel-terrain interaction testing system developed for lunar rover.A climbing-up-slope 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 16º,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 experimen-tal data are less than 10%.The model can predict wheel-terrain interaction mechanics effectively for a rover while climbing up slopes.