A generalized method for three-dimensional dynamic analysis of a full-vehicle model

Abstract

Dynamic performances of the vehicle are significantly influenced by the suspension mechanisms. An understanding of the effects of the suspension kinematics and statics (or, briefly, kinestatics) is crucial to improve the dynamic performances of a vehicle. However, the suspension kinestatics is often neglected in the dynamic analysis. This paper presents a generalized full-vehicle model for the three-dimensional dynamic analysis, which consists of two pairs of the front and rear spatial suspension mechanisms. Each suspension is represented by a corresponding instantaneous screw joint supporting the vehicle body at any instant. The full-vehicle model is viewed to be a 6-degree-of-freedom spatial parallel mechanism. As the spatial parallel mechanism, the kinematics and statics of the full-vehicle model are analysed using the theory of screws. Taking the suspension kinestatics and tyre dynamics into consideration, the dynamic equations of the full-vehicle model are formulated in terms of the Lagrangian equations. As immediate applications, the dynamic behaviours of a vehicle are simulated and evaluated under two different road disturbances, respectively. By comparing with the simulation results from two other widely used methods, it confirms the validity of the theoretical method.