Research On Coordination Control Of Hub Motors Of 4WID Electric Vehicle Based On Electronic Differential

Each wheel of 4-Wheels Independent Drive(4WID)electric vehicle is independently controllable,which increases the degree of freedom of handling stability control,but also challenges the high-precision and synchronous control of the hub motor.Therefore,for the purpose of improving the handling stability of 4WID electric vehicles,this paper studies the hub motor:Firstly,the development status of electric vehicles in china is discussed,the advantages of 4 WID in structure and control are expounded,the research status of 4 WID electronic differential control and multi-motor synchronous control is summarized,and the research scheme of hub motor coordinated control based on speed electronic differential is determined.Secondly,the dynamic model of 7DOF 4WID electric vehicle is built based on the MATLAB/Simulink simulation platform with reference to the vehicle model parameters of the CarSim database,and the correctness and accuracy of the 7DOF 4WID electric vehicle model built are verified through the comparison of constructing the CarSim/Simulink joint simulation model.Thirdly,this paper analyzes the speed electronic differential control based on the Ackerman vehicle steering model existing the lag response mechanism of the speed of vehicle wheels and puts forward BLDCM sliding mode variable structure control algorithm based on the electronic differential of the speed of the electric vehicle.Compared with torque electronic differential control,the estimation of vehicle dynamics parameters is omitted and the calculation is simplified.Compared with PI control,the response speed of the driven-wheel speed and coordinated control accuracy is enhanced,thereby improving the handling stability of the whole vehicle.Then,the basic principle of the multi-motor cross-coupling control algorithm is analyzed.The differential coefficient is obtained through the Ackerman steering model which takes as the weight coefficient of the "normalized" actual wheel speed,and the cross-coupling control algorithm of 4WID electric vehicle hub motor based on electronic differential control is proposed,which establishes the coupling relationship between the drive wheels,and improves the reliability of the coordinated control of the hub motors.Simulation verification results show that the cross-coupling control algorithm can achieve better tracking of the target wheel speed of 4WID electric vehicles,which improve the accuracy of wheel speed control and enhance vehicle handling stability.Finally,the 7DOF 4WID EV semi-physical simulation platform is constructed based on the RT box,and the correctness of the BLDCM sliding mode variable structure control algorithm based on the electric speed difference of the electric vehicle is verified through experiments;by designing the hierarchical control system structure based on CAN bus and the power circuit and control circuit of the whole vehicle,the vehicle experiment platform of Daqin ? 4WID electric vehicle is built,which verifies the feasibility of electronic differential control for 4WID electric vehicles.