Establishment and Simulation Analysis of 18 DOF Unified Dynamics Model of Automobile Chassis

The unified dynamics modeling of automobile chassis is the foundation of the chassis integrated control. Previous researches mainly focused on one or two subsystems, which could not fully reflect the dynamics characteristics of automobile chassis. In this paper, a unified dynamics mathematical model involving 18 degrees of freedom (DOF) of a two-axle vehicle is established to evaluate the ride comfort and handling stability of the vehicle, based on the coupling relationship of vehicle longitudinal, lateral and vertical dynamics. In order to verify the correctness of the 18-DOF unified dynamics model, the following three methods are used: 1) comparison with other four submodels, 2) experimental verification and 3) co-simulation test. Both simulation and test results indicate that the unified dynamics mathematical model can be used to evaluate the comprehensive dynamics performance of automobile chassis, and it is beneficial for the subsequent research of chassis integrated control system.