Tree-topology-oriented modeling for the real-time simulation of sedan vehicle dynamics using independent coordinates and the rod-removal technique

摘要

Multibody dynamics of vehicle systems can be simulated in real time using semi-recursive-based formulations and their various versions, which are normally described in terms of relative coordinates. To efficiently and accurately simulate closed-loop vehicle multibody systems, a semi-recursive formulation must be optimally combined with a numerical integration algorithm. Although a significant number of contributions has been reported in this field, there is still a need to improve accuracy and computational efficiency of real-time or faster-than-real-time simulation. This paper focuses on the loop-closure techniques that can be used when modeling vehicle systems. Consequently, a canonical tree topology is introduced to take advantage of recursive kinematics and dynamics. To this end, real-time vehicle simulations are performed based on a semi-recursive formulation and a tree-topology-oriented modeling method. The applied semi-recursive formulation makes use of double velocity transformation and independent coordinates. The introduced canonical tree topology is generated via joint-cut and rod-removal techniques. The structures of the canonical tree topologies are studied in terms of bodies, joints, constraint equations and branches. How they affect solution accuracy and computational efficiency is investigated in detail. For numerical examples, a 15-degree-of-freedom sedan vehicle model is analyzed and simulated using the semi-recursive formulation and a 4th-order Runge-Kutta algorithm in various system-tree topology cases. The results highlight the efficiency gain of the tree-topology-oriented modeling method. (C) 2019 Elsevier Ltd. All rights reserved.