Soil Mechanics–Based Testbed Setup for Lunar Rover Wheel and Corresponding Experimental Investigations

This paper introduces a testbed developed from a perspective of soil mechanics that not only focused on wheel design and optimization but also considered the elimination of the boundary effect caused by a soil bin. Using this testbed, a series of experimental investigations were performed by changing the wheel rotational velocity, vertical load, and towed load. Tracks were generated at a regular spacing as the wheel lugs enter and exit the soil periodically. It has been found that there is a relationship between the track length and wheel slip ratio regardless of different mechanical properties of soil. The wheel rotational velocity has little effect on the driving torque and sinkage. The towed load affects the driving torque more than the sinkage. However, the vertical load effects on the driving torque and sinkage are similar. The current models used for parameter estimations may not be appropriate for Tongji-1 lunar soil simulant, which has a relatively high internal friction angle according to the experimental results. But the internal friction angle and cohesion can still be estimated with proper selection of shear deformation modulus.