Abstract: Terramechanics for wheel-terrain interaction of lunar exploring rover, which is the bottleneck of dynamics-based research at present, can play an important role in mechanical design, performance evaluation, control, simulation, etc. Experiments are done by using the wheel-terrain interaction testing system developed for lunar rover. The conventional normal and shear stress distribution models are improved according to the experimental data. And the effect caused by the wheel lugs is also analyzed. To reflect the slip-sinkage caused by lateral flow of deformable soil, the concept that the sinkage exponent should vary according to the slip ratio is proposed and an empirical formula is given. Mathematic model for calculating concentrated force/torque is deduced by integrating the distributed stresses, which is verified by experimental data. With a load of 80 N, while the slip ratio increases from 0.05 to 0.6, the relative error of calculated value and experimental data for normal load, drawbar pull and driving torque is less than 10%. The model can reflect slip-sinkage and the effect of wheel lugs, and can be used effectively for the calculation of wheel-terrain interaction mechanics.

Key words: Lunar rover, Slip ratio, Terramechanics, Wheel lug, Wheel-terrain interaction