Design Of Vehicle Controller Unit For Pure Electric Vehicle

With the rapid development of the automobile industry,the two problems,such as environmental pollution and energy crisis,are also followed.Nowadays,pure electric vehicle is playing an important role in the automotive industry due to its low technology cost,zero emission,low noise and high energy efficiency.As the core component of the pure electric vehicle,the Vehicle Controller Unit plays a key role in the function of the normal driving,network management and vehicle state monitoring.This paper uses the method of combining the simulation and the position machine test and verification to design the Vehicle Controller Unit of the modified pure electric vehicle,the main tasks are as follows:(1)Division of the vehicle control function of pure electric vehicles and according to the functional requirements of the control module,the Freescale single chip microcomputer MC9S12XEP100 is chosen as the main control chip,and the hardware circuit of vehicle controller is designed,including the smallest system module circuit,communication module circuit and input and output module circuit,and then the printed circult board is drawn.Finally,the vehicle controller printed circult board assembly is finally completed,and the hardware design work is completed.(2)The control strategy of the vehicle controller is designed,and the model is built in the Matlab/Simulink environment with the parameters of the whole vehicle,and the simulation is carried out.Firstly,the pedal signal processing is carried out,the mean filter is added to the pedal signal and the first order low pass filter is used,and the pedal fault is detected.Then,the pedal signal and its change rate are input into the fuzzy controller,and the fuzzy rule is worked out to get the torque coefficient.And according to the current speed signal,we calculate the compensated torque value,and get the motor demand torque.Finally,the required torque of the motor is input into the ramp function processing module,so that the torque signal is output to the motor controller smoothly.In addition,the control logic strategy of DC/DC,electric vacuum pump and air conditioner is also designed.The simulation results show that The established control strategy can control vehicle running according to the built-in agenda,especially to ensure the steady and accurate output of the torque.(3)The C code is generated by the control strategy model and then the policy layer library is generated.According to the various registers in the singlechip mainchip,the underlying driver code is completed,and the software code of the application layer is handwritten according to the time series tasks of the whole vehicle.The strategy of calling the strategy layer library function and the underlying driver function are called in the application layer software,and the control functions of the vehicle controller are realized,so as to complete the software design work.(4)The CAN Bootloader lower computer program is completed,and combination with the USBCAN module is used to realize the download and subsequent upgrading of the vehicle controller application program through the way of CAN bus S19 file transmission.The LabVIEW position machine software is designed and the test bench is built to the function debugging of the completed vehicle controller.The results show that the result of the program runs roughly the same as our simulation results,which validates the availability of the vehicle controller and reaches our intended target.