DYNAMICS SIMULATION OF ROVERS ON SOFT TERRAIN: THEORY, ALGORITHMS, AND EXPERIMENTAL VALIDATION

摘要

A new framework is developed in this paper for the efficient implementation of semi-empirical terramechanics models in multibody dynamics environments. In this approach, for every wheel in contact with soft soil, unilateral contact constraints are added to the solver in both the normal direction and the tangent plane. The forces associated with the tangent plane, like traction and rolling resistance, are formulated in this approach as set-valued functions, whose properties are determined by dereg-ularization of the above-mentioned terramechanics relations. As shown in this paper, this leads to the dynamics representation in the form of a linear complementarity problem (LCP). With this formulation, stable simulation of rovers is achieved even with relatively large time steps. In addition, a high-resolution height-field is employed to model terrain-surface deformations and changes in hardening of soil under the wheel. As a result, the multi-pass effect is also captured in our approach. In addition, an extensive set of experiments was conducted using a version of the Juno rover (Juno Ⅱ). The experimental results are analyzed and compared with the model developed in the paper.