Four-Wheel Rover Performance Analysis at Lunar Analog Test

A high fidelity field test of a four-wheeled lunar micro-rover, code-named Moonraker, was conducted by the Space Robotics Lab at a lunar analog site in Hamamatsu Japan, in cooperation with Google Lunar XPRIZE Team Hakuto. For the target mission to a lunar maria region with a steep slope, slippage in loose soil is a key risk; a prediction method of the slip ratio of the system based on the angle of the slope being traversed using only on-board telemetry is highly desirable. A ground truth of Moonraker’s location was measured and compared with the motor telemetry to obtain a profile of slippage during the entire four hour 500 m mission. A linear relationship between the slope angle and slip ratio was determined which can be used to predict the slip ratio when ground truth data is not available.