Traction Performance Evaluation for a Rashid-1 Rover Wheel

Abstract Single-wheel experiments and discrete element method simulations of a micro-rover wheel modelled on the Rashid-1 rover designed for the Emirates lunar mission. The interaction of the wheel with Toyoura sand and FJS-1 lunar regolith simulant is studied. Slip conditions, traction coefficient and grouser pitch for single-wheel experiments are measured for a range of fixed slip values at the expected rover load of 24.5 N. The angle of repose is used to calibrate the simulation parameters with measured soil parameters. Single-wheel simulations are verified by comparison to experimental results. Lunar simulations can predict lunar gravity performance. Toyoura and FJS-1 results for traction coefficient and dynamic sinkage at 24.5 N in the 0–50% slip range show good agreement between experiment and simulation. 4.1 N lunar gravity matches the 24.5 N Earth gravity results for traction coefficient and tractive efficiency. There is a 1–2 mm difference in total sinkage. Tractive force and resistive torque reduce by 1/6 from Earth to lunar gravity for the same mass. The grouser pitch is unchanged with gravity variation. The angle of repose can independently determine parameters for use in single-wheel simulations. Experimental results validate the models for Toyoura sand and FJS-1. Wheel performance regarding traction coefficient and tractive efficiency under lunar gravity matches that under Earth gravity. Traction performance in tractive force and resistive torque is reduced by the ratio of Earth to lunar gravity, 1/6, for the same mass.