Research On Two-speed AMT Control System Of Pure Electric Vehicle

In recent years,global new energy automobile industry have a high degree of attention,our country has made great progress in new energy vehicles.Among them,the development of power performance and convenient range of pure electric vehicles has also been improved to some extent.But battery technology still limits the range of all-electric vehicles to generally shorter than conventional vehicles.And in pure electric vehicles equipped with a multi-stage automatic transmission to enhance the electric vehicle acceleration,grade ability,maximum speed,while increasing the role of vehicle mileage,as well as a pure electric vehicle research focus in the future.In addition,for Automatic Manual Transmission(AMT),the electronic control unit directly determines the quality and reliability of gear shift,and has a greater impact on vehicle dynamic performance and economy.Based on a company’s project requirements,this paper develops its control unit based on a pure electric vehicle equipped with a two-speed mechanical automatic transmission.The shift process of AMT and the factors that affect the shift quality are analyzed.Based on the economical shifting rules,a sinusoidal wave curvilinear control strategy was proposed.Then,the selection and verification of the shifting actuator,the software and hardware design of the two-speed AMT electronic control unit were completed.The MIL/SIL/HIL tests were performed to verify the feasibility and effectiveness of the shift strategy.At the same time,a two-speed AMT experimental bench and a real vehicle test platform were constructed to further verify the rationality of the design of the shift actuator and the control strategy of the application unit control layer Able to meet functional requirements.The specific research content and steps are as follows:(1)Designing economic shifting rules.Analyze the factors that affect the quality of shifting,build a sinusoidal wave curvilinear control strategy,and simulate the effectiveness of the strategy.(2)According to the needs of the project,redesign a shift actuator,and select and check the components of the shift actuator.Through the verification of shifting stroke,shifting force and shifting time,the shifting requirements are met.(3)According to the design requirements of the control unit,freescale Power PC series 32-bit SPC5634 chip is adopted as the control core,and the hardware circuit is modularized.The minimum system,power supply circuit,signal acquisition circuit,CAN communication circuit and shift motor drive circuit of the microprocessor are designed.(4)Analyze the project design requirements,complete the software design architecture of the electronic control unit,and modularize the application layer program.MATLAB/Simulink and NI Veristand tools were used to build the test HIL model,respectively,to complete the functional test of shifting process control,shift motor control,torque,speed control,fault diagnosis and other modules.(5)Set up a two-speed AMT test bench for pure electric vehicles for AMT shift calibration,shift function test,and durability test of the shift mechanism.Equipped with a real vehicle test platform,the effectiveness test of the real vehicle verification based on the sinusoidal curve lifting and twisting control strategy is performed.The experimental results show the effectiveness of each function and the integrity of the overall scheme.