Experimental Study and Modeling of Wheel's Steering Sinkage for Planetary Exploration Rovers

Steering sinkage of planetary exploration rover's wheel is the basis of its steering mechanics, which can in turn be used to the steering mechanism design, control and simulation of rovers. Systematic steering experiments are carried out using a single-wheel testbed to analyze the influence of different vertical loads, lug heights, etc. The conventional model of steering sinkage is analyzed based on the experimental results, and the conclusion that changing the sinkage exponent can fit the dynamic variety of the sinkage is obtained. Further more, two sinkage-exponent models are obtained after analyzing and identifying the experimental results. The improved steering sinkage model is deduced by the two sinkage-exponent models, and by comparing the improved wheel sinkage model with the experimental results, it is found that the error is less than 5% and the R-squares are more than 0.97, which proves the improved model can fit the dynamic steering sinkage caused by soil compression and lateral flow during the period of wheel steering.