Landing Dynamics of Telescopic-Legged Bionic Rover on Asteroid Gravel Surface Using Discrete Element Method

This study investigates the landing dynamics of a telescopic-legged robotic rover on granular surfaces of small celestial bodies, addressing the challenges posed by its high-degree-of-freedom structure. Using a custom module within the PolyDEM discrete element framework, the interaction between complex rigid bodies and nonspherical particles was accurately simulated and validated through ground-based experiments. The results reveal that retracted legs exhibit superior damping performance on coarse gravel layers by increasing localized contact area, enhancing friction, and promoting internal particle rearrangement. Conversely, extended legs perform better on fine-grained regolith by increasing penetration depth and enabling multi-point interactions, which amplify energy absorption. Additionally, this study examines the effects of impact velocity and angle on rover stability, providing actionable insights for terrain-specific deployment strategies. These findings advance our understanding of high-DOF robotic systems in extraterrestrial environments and offer practical guidance for future mission planning.