Steer-by-wire System Control Strategy Research

It is important for steering system to implement steer and control the vehicle maneuverability and handling characteristics. A steer-by-wire system has many benefits over conventional steering system for no mechanical link existing between the steering wheel and the road wheels. The steering instructions given by operator are transmitted to the steering controller, then the steering operation are implemented by the steering controller after analyzing the instructions, vehcile status and road conditions. At the same time, the road information must be transmitted to the driver, the road feeling is generatd by the road feeling motor virtualy.Firstly, the steering system and steer-by-wire system development and research status are depicted in this paper. Secondly, the steer-by-wire system steering system dynamics model is built and analized after introducing the steer-by-wire system structure and principle. The vehicle dynamics model for control strategy reaearch is built in ADAMS. The research platform about the steer-by-wire system hardware-in-loop is developed. The steering capability is not only ralative to the steering angle, but also the speed and vehcile dynamical parameters. The relation is described difficultly through the math function, the fuzzy control technology can be applied in the nonlinear widely. So there is a trial research in varaible structure fuzzy varaible ratio in steer-by-wire system. There is a simulation analyses about the varaible structure fuzzy variable ratio control strategy through the Matlab and ADAMS, and then make an experience with the hardware-in-loop. The road feeling is generatd by the road feeling motor virtualy with the road feeling fuzzy decoupling control for no mechanical link existing between the steering wheel and the road wheels. There is a simulation analyses about the road feeling fuzzy decoupling control strategy through the Matlab and ADAMS, and then make an experience with the hardware-in-loop.The research result shows that varaible structure fuzzy varaible ratio works well at the set yaw range. The steering force characteristics can be convenient to generat and set through the road feeling fuzzy decoupling control. The last part gives the conclusion with the shortcoming of this paper and the future work.Steer-by-wire system control strategies are researched in this paper for the purpose of research the steer-by-wire system and developing the sample vehicle. There is not find the same strategy reported in relative paper about the varaible structure fuzzy variable ratio control strategy and the road feeling fuzzy decoupling control. The paper provides an important theroy and practice basis for developing the sample vehicle, especially the control strategies of steer-by-wire system hardware-in-loop experiments.