Research On Road Feeling Simulation Control Of Automobile Steer-by-Wire System

The steering by wire system replaces the mechanical connection part of the traditional steering system in the form of electrical signal,resulting in the road information can not be transmitted to the driver in the form of steering wheel torque,which directly leads to the driver losing a certain sense of security.This paper studies the road feeling simulation control technology.Its main work is to simulate the steering resistance torque through sensor measurement method and dynamic calculation method,design the road feeling simulation torque preferred by the driver,and control the road feeling motor to realize this torque to the steering wheel to complete the road feeling simulation.By analyzing the structure and working principle of the steering by wire system,the dynamic model of the steering by wire system is built,and the correctness of the model is verified by the joint simulation test of Matlab/Simulink and Carsim.The steering resistance torque is simulated by sensor measurement method and dynamic calculation method respectively,and the three degree of freedom vehicle state estimation model is established.The extended Kalman filter algorithm is used to obtain the vehicle centroid sideslip angle and yaw rate required in the dynamic calculation method.Through the snake condition simulation test at 80km/h,it is verified that the steering resistance torque obtained by the above two methods is basically consistent with the change trend and peak time of the actual steering resistance torque.The bus current of steering executive motor is obtained by Kalman filter algorithm,and the reliability design is carried out by using the residual between the measured value and the estimated value;set the failure test to verify that when the current sensor fails,the simulated steering resistance moment is still basically consistent with the actual steering resistance moment.The steering resistance torque is transformed into the steering wheel torque under the mechanical steering system,and on this basis,the angular variable transmission ratio is designed based on different vehicle speeds;analyze the change relationship between speed,lateral acceleration and steering wheel angle and the driver’s preferred road feeling torque,and carry out the correction design of the driver’s preferred road feeling simulation torque based on different speeds,lateral acceleration and steering wheel angle on the basis of the steering wheel torque under the mechanical steering system.Finally,through relevant tests,verify the effectiveness of the designed angular transmission ratio and the correction design.The PID controller is designed to control the road sense motor and realize the road sense simulation torque preferred by the driver to the steering wheel.The simulation shows that it can better realize the road sense simulation function of the road sense motor;through the simulation test of double button line and high-speed central area steering condition,it is verified that the road feeling simulation torque designed in this paper has better low-speed portability and high-speed stability than the mechanical steering system.