Design of Landing-Gear Footpad Based on Resistive Force Generated by Celestial Soil

Abstract

Minimizing the risk of tipping during landing is critical for achieving successful celestial surface explorations by moon, Mars, and asteroid landers. The footpad is an important part of the mechanism for tip-over prevention of landers because it is the only mechanical part that contacts the terrain surface during landing. The force that acts on the footpad depends on its shape, and so its design is important in preventing overturning of the lander. This study describes the relationship of the attachment angle of the footpad and the force that acts on it based on resistive force theory. This theory describes the relationship between the state of the mechanical part in granular media and the force that acts on its surface. Based on this theory, the footpad’s attachment angle is optimized. The relationship between landing performance and the attached angle of the footpad is confirmed through dynamic simulations. The simulation results show that the tilted footpad is effective for safe landings under conditions in which there is a horizontal velocity component during landing.