Desgin And Control Research Of Electric Steer-by-wire System

With the development of vehicle electrification and intelligence,vehicle structure has become more and more complex.Electric vehicles,intelligent vehicles and self-driving vehicles become the development trend of the automobile industry.A key point of intelligent driving is the drive-by-wire technology.This dissertation focuses on the research of steer-by-wire(Sb W)system in deep,which includes the steering system architecture design,structural design,and the system controller design.Firstly,this dissertation proposes a new type of electric steer-by-wire system architecture.3D modeling software to is utilized to design the steering system which is assembled to an electric vehicle chassis.The simplified mathematical model of the steering actuator is derived by the second-order differential equation.The functional relationship between the steering actuator transmission ratio and the front wheels angle is analyzed in detail.The self-aligning torque from the road are simplified into an equation.Based on the purpose of steering angle tracking,model predictive control(MPC)algorithm is adopted to design the Sb W controller,the sliding mode control algorithm is also introduced for the disturbance torque compensation.Finally,the motor torque is controlled to realize that the front wheel steering angle can effectively tracking the reference angle.Simulation test is used to initially verify the effect of the designed algorithm and system model.A hardware in-loop test platform for Sb W system is set up based on the designed steer-by-wire system structure.Various working conditions,including steering angle tracking tests and double land change test,were used to test and verify the system and control algorithm.The experimental results indicate that the front wheel angle can effectively follow the reference angle instruction,and the driver can effectively manipulate the steering system for steering under specific trajectory conditions.Experiments also verifies the feasibility of the Sb W mechanism structure assembled on the chassis of the vehicle.