DEM-MBD Coupled Simulation of a Burrowing auger-shaped Robot in Dry Sand

This study demonstrates the application of a coupled discrete element method (DEM)

– Multi-body Dynamics (MBD) framework in simulating the self-burrowing behavior of a robot in dry sand. In robotics, a robot can be modeled using MBD, in which each component of the robot is modeled as interconnected rigid or flexible bodies whose motions obey the laws of motion and are limited by kinematic constraints. In this study, DEM is coupled to MBD using Chrono – an open-source physics engine – to model the self-burrowing behavior of a two-auger robot in dry sand. The self-burrowing robot consists of two horizontal augers that are connected using two motors defined in DEM. A typical co-simulation loop starts with the DEM module that solves the inter-particle and particle-structure forces and displacements; the particle-structure forces are then transferred to the MBD module to solve the dynamics of the robot; the updated kinematics information is then transferred back to the DEM module. The design of the augers and the geometric parameters was studied to better understand the effect of geometry on the driving force of the robot. The values of the pitch ratio of the shaft and cone were changed to comprehend the effect of the blades of the augers on the self-burrowing driving force.