Modular Multibody Formulation for Simulating Off-Road Tracked Vehicles

Abstract

This paper presents a formulation and procedure for incorporating the multibody dynamics analysis capability of tracked vehicles in large-scale multibody system. The proposed self-contained modular approach could be interfaced to any exiting multibody simulation code without need to alter the existing solver architecture. Each track is modeled as a super-component that can be treated separate from the main system. The super-component can be efficiently used in parallel processing environment to reduce the simulation time. In the super-component, each track-link is modeled as separate body with full 6 degrees of freedom (DoF). To improve the solution stability and efficiency, the joints between track links are modeled as complaint connection. The spatial algebra operator is used to express the motion quantities and develop the link’s nonlinear kinematic and dynamic equations of motion. The super-component interacts with the main system through contact forces between the track links and the driving sprocket, the support rollers and the idlers using self-contained force modules. Also, the super-component models the interaction with the terrain through force module that is flexible to include different track-soil models, different terrain geometries, and different soil properties. The interaction forces are expressed in the Cartesian system, applied to the link’s equation of motion and the corresponding bodies in the main system. For sake of completeness, this paper presents dynamic equations of motion of the links as well as the main system formulated using joint coordinates approach.