Development Of Hardware And Software For Two-speed AMT Control Unit Of Pure Electric Vehicle And Bench Test

With the rapid development of new energy automobile industry,pure electric vehicle dynamic performance and mileage have been greatly improved.However,compared with the traditional internal combustion engine vehicle,pure electric vehicle still has a certain gap in these respects.Pure electric vehicles equiped with multi-speed transmissions which could improve the acceleration ability,the grade climbing ability,the maximum speed and increase the vehicle mileage are the future development trend.For pure electric vehicles equipped with two-speed AMT,the AMT control unit can directly determine the shifting quality and reliability,so the development of AMT control unit has great significance.In this paper,the factors that affect shift quality during the AMT shift process of pure electric vehicles are analyzed,the economic shift schedule is designed.Then the AMT control unit hardware and software is developed.The bench test results obtained show that the application layer software can satisfy the functional requirements.The specific research contents and methods are as follows:1.The shiting process is analyzed,and the mathematic model of gear shifting process is established to study the factors that affect shifting jerk.In order to increase the vehicle mileage,an economic shift schedule is designed based on a pure electric vehicle.The simulation is carried out with the AMESim and Simulink softwares.The simulation model of pure electric vehicle equiped with two-speed AMT is built in the AMESim and the shift control strategy is designed in the MATLAB/Simulink.The AMT gear changes and the SOC value of the power battery under the NEDC driving cycle are obtained.Simulation of pure electric vehicle equipped with fixed-ratio gear box is conducted in the same way.The simulation results indicate that the economic shift schedule is reasonable.2.The function requirements of the AMT control unit in pure electric vehicle are analyzed.The circuit diagram of AMT control unit is designed,which includes the minimum system of the microcontroller unit,the switch signal processing circuit,the analog signal processing circuit,the frequency signal processing circuit and the shifting motor driving circuit.Based on the hardware reliability design rules,the PCB structure is designed finally.3.The TCU embedded operating system is developed based on the ?C/OS-? to improve the real-time performance of task processing.The application layer software is designed on the MATLAB/Simulink platform,which consists of the signal acquisition component,the strategy management component,the shifting execution component and the driving motor torque recovery control component,then the corresponding target C is automatically generated by MATLAB/RTW.The static self-learning strategy for AMT gear position is developed by using C language.4.Pure electric vehicle AMT test bench is set up,the AMT gear position parameters are calibrated.The application layer software is tansplanted into a mature TCU product for the dynamic shifting test,TCU can control the driving motor and shift actuator to complete the upshift and downshift action.The result shows that the application layer software of AMT control unit can satisfy the design requirements.