Research On Coordinated Control Strategy Of In-wheel Motors For 4WID/S Electric Vehicle

The output torque and rotation angle of the four wheels of the four-wheel independent drive/steering electric vehicle are independently controllable,which greatly improves the operational stability and maneuverability of the vehicle,and has received extensive attention and research.The increase of actuators brings control challenges,so the coordinated control of wheel drive motors has become a hot spot in the research field of four-wheel independent drive/steer electric vehicles.In order to coordinate and stabilize the four-wheel independent drive/steering electric vehicle,this paper studies the coordinated control of the wheel drive motor when the vehicle is running.The main research contents are as follows:Firstly,the structure and main performance parameters of the four-wheel independent drive/steering electric vehicle are designed,and the vehicle power matching is carried out according to the vehicle dynamics formula.By comparing the performance of the driving motor of the electric vehicle,the permanent magnet brushless DC motor with external rotor is selected as the driving motor,and its mathematical model is established.Secondly,a speed loop controller based on the first-order linear ADRC is designed,and the stability and frequency band characteristics of the first-order linear ADRC are analyzed.The wheel-driven motor control algorithm combining direct torque control and linear ADRC is adopted.The simulation results show that the algorithm improves the dynamic and static performance of the driving motor.Thirdly,based on the hierarchical concept,a coordinated control strategy of wheel-driven motor based on linear ADRC-bias coupling synchronous control and electronic differential control is proposed for four driving modes of four-wheel independent drive/steering electric vehicles,namely,linear driving,conventional steering,in-situ steering and translation steering.The correctness of the proposed control strategy is verified by simulation.Finally,the experimental plaform of four-wheel drive/steering electric vehicle drive system is built.Tne control structure based on CAN bus and distributed and centralized control is adopted.The hardware and program of the experimental platform arc designed with DSP TMS320F28335 as the main control chip.The control algorithm of wheel drive motor and coordinated control strategy of wheel drive motor arc experimentally validated,and the experimental results prove that the proposed control algorithm and coordinated control strategy of wheel drive motor are effective.