Road-feeling Design Of Steer-by-Wire System With Multiple Information Cooperative Perception

The automobile steering system is the hub connecting the driver and the car.Obtaining an accurate road feel plays an important role in the initiative safety technology of the vehicle.At the same time,the emergence of steer-by-wire technology has brought new developments to the car steering system,which provides more convenient and safer highway driving for both drivers and vehicles.Since the steering information cannot be transmitted through the mechanical structure in the steer-by-wire system,and the road feel needs to be generated by simulation,a effective road feel design is extremely important for the vehicle steering system.In response to this problem,this paper also studies the roadfeeling design of the steer-by-wire system.Aiming at the problem that the vehicle state parameters affect the road sense acquisition in actual driving,and by analyzing the common methods of state estimation and the advantages and disadvantages of different fusion algorithms,a fusion algorithm based on unscented Kalman filtering is proposed to obtain real-time vehicle state parameters.The method adopted in this paper is mainly to design the vehicle state estimator based on the easy-to-measure car conditions,which is based on the fusion theory of unscented Kalman filter,to estimate the required difficult-to-measure vehicle driving state parameters,and to compare with the results of vehicle driving state parameter estimated by fusion algorithm based on extended Kalman filter theory.The simulation results show that the fusion algorithm based on the unscented Kalman filter can more accurately estimate the vehicle driving state parameters,and is more suitable for the steering-by-wire system vehicles.It provides the theoretical basis and design ideas for the subsequent road surface adhesion coefficient estimation and vehicle control strategy research,which helps to improve car control stability.Aiming at the road-feeling design problem of the steer-by-wire system and,based on the nonlinear 3 freedom degrees vehicle model,this paper proposes a road information planning method with multi-information fusion by analyzing the road feel generation mechanism and the currently used road-feeling design method.First,by analyzing the basic unit structure of the steer-by-wire system,and on the basis of the Simulink model of steerby-wire system composed of the steering wheel,steering motor,rack and pinion,and steering front wheels,a nonlinear three freedom degrees vehicle model based on the "magic formula" tire model was established.Second,the assist torque and compensation torque are obtained by analyzing the influence of vehicle speed and variable transmission ratio on the road feel,which is superimposed on the steering resistance torque calculated by the dynamic model to form the road feel.Finally,based on the fuzzy immune PID control method,the vehicle feel control strategy of the steer-by-wire system is designed to verify the effectiveness of the feel in the nonlinear vehicle model.The simulation results show that the road feel planning method enables the driver to obtain accurate road conditions,perceive the real-time driving status of the car,and realize the real-time,comfort and stability of the road feel to a certain extent.