Influence of rim radius on zero radius steering resistance moment of drum-wheel for lunar rover

In order to provide a theoretical basis for wheel configuration design, motion control, vehicle simulation of a lunar rover, based on the terramechanics, a judgment method for sinkage of a drum wheel is presented. The shear and bulldozing characteristics acting on the interaction of wheel-soil for the steering wheel are investigated, and a zero radius steering mechanical model for the drum-wheel is established. Theoretical analysis reveals that the steering resistance moment increases asymptotically with the increase of the rim radius. The drum wheel with smaller rim radius has the smaller value of steering resistance moment, which has better steering ability than the cylinder wheel. To validate the steering model, a single-wheel test bed is employed to test the steering performance of the wheels with two kinds of rim radiuses. The experimental results show that the theoretical model is correct.