Direct Yaw Moment Control Of Four Wheel Steering Vehicles And Hardware In Loop Simulation System

Four wheel steering technology is an important method to improve vehicle steering performance. Vehicle stability control system is a leading technology in active safety. As an important part of VSC system, direct yaw-moment control improves the performance of handling stability much better, then increases the active safety performance. This dissertation connects four wheel steering control and direct yaw-moment control, designs the controller based on the feedback of status parameter, does much work on the simulation with the tool of MATLAB/Simulink. In addition, the author has finished the work of hardware in loop experiment of four wheel steering system. The main content contains:1 Author sets up the vehicle model of front wheel steering with direct yaw moment control, designs the controller based on the feedback of status parameter with tools of optimization theory and H∞control theory separately, gives the simulation results with the tools of MATLAB/Simulink and the results show that the controller has a good effect and the vehicle has a better performance than front wheel steering vehicle.2 Author sets up the vehicle model of four wheel steering with direct yaw-moment control, based on the optimization theory, uses the method of both forward feed and back feed to design the controller, simulates the behavior with the controller and the results show that this system has better performance than not only front wheel steering system but also front wheel steering plus direct yaw moment system.3 Author analyzes synthetically methods of hardware in loop simulation, sets up a four wheel steering experiment platform, connecting with four wheel steering control strategy, uses DSPACE system to design the hardware in loop four wheel steering system, uses MATLAB/Simulink to realize software part and ControlDesk to realize the real-time adjustment of parameters, and achieves the simulation results.4 Author uses TMS320F2812 DSP as electronic control unit to realize hardware in loop simulation, realizes the state flow of four wheel steering hardware in loop system, develops ECU module for four wheel steering system, Introduces hardware resources, development software CCS etc, develops and debugs programs of the whole system, gives a detailed introduction of four wheel steering interruption subprogram.Through setting up the mathematic model and digital simulations, it can be seen that the strategy of connecting four wheel steering and direct yaw moment control takes a good effect that all evaluating parameters have a much better performance and vehicle behavior improves greatly. Through the hardware in loop experiment, connecting hardware and software system, you can easily adjust those control parameters. It has good merit of multiple experiments, greatly improves the performance in economics. Developing ECU module for four wheel steering system does much good for the improvement of electric control and decrease of cost, which is very good for the manufacture in large scale of four wheel steering vehicle.