反映载荷影响的星球车车轮试验及模型研究

When the planetary rover is moving up/down a hill or using peristaltic or wheel-lifting gait, the vertical load on its wheels will change significantly. Analyzing the impact of the vertical load on the wheel-terrain interaction can provide support for the rover’s extraterrestrial exploration. The single wheel experiments under different vertical load are carried out using a single-wheel testbed, the changing trends of wheel sinkage, driving resistance torque and drawbar pull with vertical load are obtained. Taking the approximate load value 160 N for the average load of the six wheels of the 240 kg Mars rover as a typical situation, the sensitivity of each parameter in the wheel-terrain interaction model is analyzed using an analytical method. The results show that the bearing characteristic parameter sinkage exponent and the shearing characteristic parameter soil internal friction angle have higher sensitivity. The influence of wheel load on the wheel-terrain interaction model is analyzed based on the results of experiments and sensitivity analysis, and a sinkage exponent model reflecting the influence of the load is established. The goodness of fit of the model to the experimental data can reach 0.99, the estimation error of the drawbar pull is mostly within ±5 N, and the estimation error of the wheel sinkage is less than 3 mm.