Research On Modeling And Roll Stability Control Of Commercial Vehicles

Due to the characteristics of high center of gravity,large volume and relatively small track,the lateral stability of heavy commercial vehicle is relatively lower,bringing many rollover accidents.Therefore,how to use active safety system to improve its roll stability is an important subject of today’s scholars.For instance,roll stability control system which is a typical active safety system.Based on the previous research results,this paper builds the roll stability control system based on the three-axle vehicle dynamics model to improve the roll stability of heavy commercial vehicles.The specific contents are as follows:Firstly,the model of some kind of vehicle is established in ADAMS/Car software,and the important parameters of ADAMS model are identified by combining genetic algorithm and L-M numerical optimization algorithm under typical operating conditions.Based on the dynamics of the automobile system,the 2DOF model of the three-axle vehicle is established.The simulation model is established in the MATLAB software and the accuracy of the model is verified by comparing the simulation data of 2DOF model with ADAMS model under the step condition.Secondly,based on the theory of multi-body dynamics and D’Alembert,and considering suspension K&C characteristics,the rear axle twins three-axis vehicle nonlinear dynamic model of 26DOF is established.The improved Euler iterative method is used to solve the system of differential equations of vehicle dynamics,and the simulation system is compiled in MATLAB.The simulation results are compared with the simulation data of ADAMS and TruckSim models.The experimental results show that the model is accurate and efficient.Finally,a linear 3DOF model of three-axle is established as a reference model for establishing rollover warning system.Transverse Load Transfer Rate(LTR)is selected as the rollover warning index and the rollover threshold LTRmax is established.Based on the dynamic rollover warning algorithm(TTR)to establish rollover warning system and based on the principle of differential braking,using additional yaw moment to restrain the occurrence of rollover.Based on LQG algorithm to determine the size of the additional yaw moment.In order to control the size and direction of the yaw moment,a differential braking control regulator is established and the braking torque is distributed by controlling the brake cylinder pressure.Then,the stability control system is written in MATLAB and embedded in the three-axis vehicle dynamic model of 26DOF.Finally,the validity of the roll stability control system is verified under the angular step steering and the hook steering simulation condition.