Study On Differential Steering Control Of Four-wheel Independent Drive Intelligent Vehicle

With the environmental problems and resource problems brought by traditional cars,researchers are looking for a new energy vehicle. Because of the need of renewable energy, low noise and precise control, electric vehicles have been paid more and more attention. Now most of the electric vehicles are the traditional internal combustion engine into the motor, the other mechanical structure has not changed any, did not play the advantages of electric vehicles. Four wheel independent drive technology, especially the independent drive technology of the hub motor, can play the advantages of independent control of the hub motor, for the development of electric vehicles into the vitality. The core of the technology is the need for a complete set of control systems and theory. Now the research on this aspect is still not mature,so the prototype research group to build the four wheel independent drive intelligent vehicle based on the prototype of the steering control research.In this paper, the steering mode of the four wheel steering is studied, and the dynamic law of the steering of the intelligent vehicle is studied from the aspects of the whole vehicle, the internal structure of the steering system, the front and rear axles, and the electric wheel. The law of motion of vehicle from straight to turning, especially the law of steering instantaneous center,is studied in detail. The motion law between the steering systems is analyzed during the vehicle steering. The dynamic model of the interaction between the electric wheel and the ground is analyzed. Grasp the movement law of differential steering of intelligent vehicle, lay the foundation for subsequent intelligent control. Briefly introduces the layout of drive system of intelligent vehicle, control strategy of the vehicle and on the basis of the research, studied intelligent vehicle four wheel drive motor coordination control strategy, control strategy and vehicle traction control strategy etc.. The four wheel coordinated control strategy is used to analyze the uniform linear motion, the turning motion and the mutual conversion between them.When driving motor control strategy is studied, four aspects are studied, which are voltage control strategy, speed closed loop control strategy, torque closed-loop control strategy and vehicle traction control strategy. The intelligent vehicle steering trapezium was selected and optimum design of the objective function,a new objective function is proposed. The objective function is used, which can reveal the basic rule of accurate instantaneous center of rotation changes. Then, the hardware part of the differential control system is studied from three aspects of the design goal, the mechanical structure and the electrical system, and the experimental verification of the real car is carried out.In this paper ,the output speed and torque controller through the vehicle to coordinate four wheel motor, so that both sides of the steering wheel speed difference, while driving steering pull the steering wheel rotates a certain angle, thus traction vehicle steering motion. Through the verification of the four wheel steering mode,this paper will bring a new and unique steering mode for the whole wheel independent drive vehicle, and expand the types of the steering mode.Therefore, the study of this paper has theoretical value and practical significance...