Design On Control System For Four-wheel Independent Drive Electric Vehicle

Both in energy and environmental pressures, electric vehicle(EV) has become the development trend of automobile industry,because EV have advantages including energy-saving,zero-exhausting and low noise etc.Among which, The four-wheel independent drive EV is one of the developing directions for further EV. Because of its perfect controlling performance and potential in engineering applications, more and more efforts have been devoted to the four-wheel independent drive EV by both academicians and engineers alike, the development of this technology botained vigorously promote by large Research institutions at domestic and abroad, and many achievements also have been introduced.This thesis complies with the current issue, carry on research in the present situation and development trend of EV and the key control technology of four-wheel independent driving vehicle at home and abroad. This thesis takes 4WD whole vehicle control system of vehicle as the main research object, and By the design and realization of the complete control system, Mainly includes hardware and software system of vehicle controller and motor controller.Firstly, select the appropriate system to use the drive motor, followed by Depth analysis of the wheel brushless DC motor working principle,mathematical models and four-quadrant operation modein.Secondly, the hardware and software of wheel motor drive controller based on PIC18F4685 are designed. In terms of hardware focused on the inverter circuit of controller and the device selection and some auxiliary circuit design of inverter circuit. On the basis of the hardware circuit is also conducted design ofsoftware architecture. The programme of Electron commutator and speed /current PID regulation is Stressly specified. Eventually wheel brushless DC motor's double closed loop speed regulate control is realized.For the core control unit of paper vehicle conteoller system should have the functionality and technical requirements for a detailed description. While the whole vehicle controller based on the ARM chip STM32F103ZET6 is designed with description of hardware makeup. The whole vehicle controller is content to request of system function, easy to emulator and debug, easy to extend.In experiment,the CAN network was designed for information exchange between the motor controller and the whole vehicle controller. At the same time CAN2.0B is selected as bus communication protocol. Standard data frame is selected. The priority of news is arranged. The corresponding relation between ID and priority of news is given. software of the CAN communication is detailed in the paper. At last the paper makes a brief on principle of regenerative braking and selects a good structure of programs and good control strategy on regenerative braking.