Computational Studies on Interactions between Robot Leg and Deformable Terrain

Abstract

Dynamic interactions with soft terrain occur in many natural and engineering systems. These events are usually associated with large deformations and plastic flows, which generate unique challenges for grid-based techniques because of local grid distortions. To overcome this issue, the application of Smooth Particle Hydrodynamics (SPH) method is first extended by the authors to the field of terradynamics, in particular, the continuum simulation of legged locomotion on soft soil media. Soil models with and without consideration of plastic failure are introduced to capture the behavior of loose and dense soil terrain. In one of the models considered for legged locomotion, a pendulum model is used to study a swinging mode. Locomotive interactions across different frequencies are introduced to realize quasi-static deformations and rapid collisional flow phenomena. The results obtained from numerical studies reveal that the soil behavior during locomotive interactions can be realistically simulated with the SPH framework. Compared with a dense soil terrain, a loose soil terrain has better characteristics of energy storage and dissipation. These findings can be helpful for understanding possibilities for robot navigation and exploration in unknown and complex terrains.