Modelling of flexible metal wheels for planetary rover on deformable terrain

Rovers are one of the most important vehicles used for conducting planetary exploration missions. On deformable terrain, traction is limited by the mechanical properties of the soil; therefore, a lack of traction and wheel slippage causes difficulties during operation of the rover. One possible solution for increasing the traction force is to increase the size of the wheel-terrain contact area. Flexible wheel forms can change depending on terrain conditions. So, flexible wheels exhibit high performance in traversing deformable terrain. However, the flexible metal wheel-terrain model for a planetary rover on deformable terrain has not yet been presented in detail. In this paper, a flexible metal wheel and a flexible wheel model that can quantitatively evaluate the sinkage and traction performance of flexible metal wheels on deformable terrain are designed. The theory has been built over the existing equations and validated with by test results. This paper establishes models for estimating static sinkage and dynamic wheel-terrain interaction mechanics. Experimental results from a single-wheel test show that the model can be used for mobility prediction with good accuracy. Based on the calculated model values and experimental results, the drawbar pull and torque of the flexible wheel clearly increases and sinkage clearly decreases compared with a rigid wheel of the same dimensions. The new model can be used to predict the traction performance of flexible wheels. This study can provide a reference for the flexible wheel design of planetary rovers.