Development And Test Research On Algorithm Of Steering Wheel Reaction Force Of Steer-by-Wire System

The Steer-by-Wire(SBW)has the advantages of flexible layout,customizable steering feel,and active steering function.It will be used in many cars in the future.This paper focuses on the SBW system steering wheel reaction simulation algorithm.Based on the analysis of the mathematical model and control principle of the permanent magnet synchronous motor,the problem of improving the current following response of the steering motor is studied.The deadbeat current prediction method is used to reduce the response delay.The experimental results show that compared with the basic PI control method,the current follow-up effect is significantly improved after applying the feedback decoupling current without beating prediction.In the SBW system,the consistency between the steering wheel and the road wheel movement is a basic requirement.Because there is no mechanical connection between them,the combined effect of the steering hand force and the steering load moment causes the complexity of the dynamic consistency problem,this is the "bidirectional control" problem in SBW systems.Based on the analysis of various bidirectional control schemes,this paper selects the scheme of position control and force feedback.Its core issues include wheel angle control,steering load torque observation and steering wheel reaction force reconstruction.The problem of wheel angle control was studied.Due to the existence of system inertia lag,it is difficult to further improve the follow-up effect by using only the PI feedback control.Under this understanding,a feedforward link is constructed,a feedforward and feedback control scheme is adopted.Simulation and experimental studies were conducted.The experimental results show that the hysteresis and accuracy of wheel following control basically reach the level of practical application.Steering wheel reaction force reconfiguration is also a core control technology of SBW system.Based on the analysis of the principle of EPS control,a steering wheel force reconfiguration scheme based on the principle of EPS control is proposed,including steering main torque decision,inertia compensation,friction compensation and damping compensation.This program has the advantages of clear and concise routes,easy calibration and adjustment,inherited EPS core control technology and other advantages.A hardware-in-the-loop experimental platform for rapid prototyping controllers and actuators was built to carry out experimental research on the above strategies.The experimental results show that: 1)The proposed steering wheel reaction reconfiguration strategy achieves an ideal steering reaction force simulation function;2)Applying the "position control-force feedback" type bidirectional control scheme,a good steering wheel angle consistency with the front wheel angle is obtained.In the in-place steering obstacle experiment and steering return positive experiment,obtained similar steering characteristic with the traditional car.Steering load torque observation is also a core strategy of steering wheel reaction simulation.Due to limited energy,this article only carried out exploratory research.In the hardware-in-the-loop simulation experiment of the steering wheel reaction force simulation strategy,the rack force sensor was used to instead of the steering load force observation.