Enhancing the tractive performance of unmanned vehicles using an optimised wheel-step driving system

A wheel-step driving system that can realise a wheel-step driving mode is proposed to improve the tractive performances of wheeled unmanned vehicles when driving on soft roads. Although the wheel-step driving system proposed in this paper adopts double wishbone suspension, it also can be applied for different suspension configurations after adjustment. In this paper, a typical sandy soil and a designated tyre are selected as hypotheses to verify the enhanced effect of wheel-step driving system on tractive performance. First, the wheel-soil interaction mechanism of the wheel-step driving mode is analysed based on terramechanics theory and the wheel-step driving strategy is optimised. The tractive performances of the wheel-step driving mode and the normal driving mode are compared and analysed through numerical calculations. Then, a soil model is established using discrete element software and a wheel model is established using dynamics software; the coupled simulation of the dynamic and discrete elements compares the drawbar pull, the driving torque and the sinkage in the normal driving mode, the wheel-step driving mode and the optimised wheel-step driving mode. The simulation data verify the effectiveness of the optimisation strategy used and the enhancement effect of the wheel-step driving mode on the traction performance. Finally, a soil-bin test system is built and a tractive performance experiment is performed. The experimental data and the simulation data show good agreement, thus verifying the correctness of the simulation model.