Study On Control Strategy Of Steer-by-wire System Based On Model-based Design

As an important part of the car, steering system determines the safety and stability of thevehicle operation. Conventional steering system is not only likely to cause fatigue, but also it leadsto a certain degree of resource wastage because it works all the way whether it needs to turn or not.The steer-by-wire system brings tremendous innovation to the automotive industry under thisbackground. Steer-by-wire system is called SBW system for short. It combines computertechnology, electronics and intelligent control technology. It transfers control instructions throughelectric signals and the drive ratio can be designed at will, so it has good steering performance. Butas a new technology, the reliability of the steer-by-wire system is not as high as the conventionalsteering system, so a lot of experiments are needed. By building the model-based test platform, thisarticle simulated and analyzed the control strategy of the steer-by-wire system, not only did iteconomize a lot of manpower and resources, shorten the experimental period, but also it avoided therisks that existed in the vehicle tests. So it provided theoretical support and engineering guide forthe study of steer-by-wire system.Firstly, this article put forward the road feeling and the road resistance simulation programbased on the structure and principle of the steer-by-wire system. Then the motors and sensors thatused in the platform were selected. Next, the platform carriage was designed through the Pro/Esoftware and the simulation platform which was the control core to build the simulation model wasestablished based on MATLAB and DSP.Secondly, this article built the kinetic model of the steering operation module and the steeringexecution module based on the reduced-order kinetics. In order to analyze the performance of thewhole vehicle and provide reference for the road resistance equipment, the two freedom model andthe steering resistance module of the vehicle were built too.Thirdly, this article built the ideal model of the drive ratio based on the constant yaw rate gainand the constant lateral acceleration gain respectively. Then the control strategy of the steer-by-wiresystem was analyzed. The front corner strategy used the method of PID angle tracking and the roadfeeling used the PID control and the fuzzy PID control methods respectively. By simulating thestrategies in MATLAB, it indicated that the PID angle tracking strategy can completing the steeringand the fuzzy PID method performed better in imitating the road feeling.Finally, the platform was installed and debugged based on the above study. To verify thepractical application of the control strategies, the strategies were tested in the platform. The results of the test showed that the control strategy can satisfy the steering and road feeling requirementswell.