Massively Parallel Discrete Element Modeling of Legged Mobility on Granular Terrain

Legged mobility of robotic systems is an active area of research. Quantitatively understanding mobility of these systems on natural terrain is critical for design and operations of these systems. In this paper, we present results of computational simulations of legged mobility on granular terrain using massively parallel Discrete Element Method. We model the interactions of a leg from a micro ground vehicle with sandy terrain made of polydispersed granular media. In these simulations, we model the interactions between millions of granules and the leg to quantify ground reactions and associated qualitative behaviors. The simulations are run on parallel computers to overcome the severe computational complexity of simulating these large problems in physically feasible time-frames. We are using high fidelity first-principles approaches to model emergent complex behavior that cannot otherwise be modeled. We present results from a parametric sweep where different leg speeds and penetrations are used to understand differences in ground reaction.