Scm – a Soil Contact Model for Multi-body System Simulations

The paper introduces a new simulation tool called Soil Contact Model (SCM) that has been recently developed at DLR’s Institute of Robotics and Mechatronics. SCM provides an interface between the classical terramechanics theory of Bekker and the capabilities of multi-body system (MBS) simulation technique for general, full 3D simulations of soil contact dynamics problems. Beyond the computation of contact forces and torques, a further key component of SCM is the computation of plastic soil deformation during physical contact with wheels, tracks, legs or any other arbitrarily shaped contact objects. It comprises features such as generation of the contact footprint, displacement of soil material and landfill around the contact zone. These features enable SCM to compute typical terramechanical phenomena like (1) rising rolling resistance caused by humps in front, (2) lateral guidance inside ruts, (3) drawbar pull variations versus slippage and (4) multi-pass effects of wheels running inline. Unlike volumetric, FEM/DEM-like approaches SCM computes all required data based on relative kinematics between discretized contact surfaces. Therefore, the computational efficiency is quite high and adequate for MBS applications. In the paper the architecture and the key features of the implementation are presented. Simulation performance and sensitivity aspects of SCM are addressed in chapters on verification and correlation with experimental results.