Study On Transient Shift Control Of Two-speed AMT Of Pure Electric Vehicle

Nowadays,environmental pollution and resource depletion have become a worldwide problem.Countries around the world have introduced relevant policies and measures to solve environmental pollution and alleviate resource depletion.The traditional fuel vehicles with serious air pollution and fuel consumption have become the focus of the public.Almost all automobile manufacturing countries have formulated a fuel vehicle exit schedule and increased the research and development of new energy vehicles.Among them,pure electric vehicles have become an important development direction of new energy vehicles with their clean and pollution-free characteristics,but most of the pure electric vehicles still have a certain gap in performance compared with fuel vehicles.In order to narrow this gap,a lot of research has been carried out on pure electric vehicles by automobile and parts enterprises and relevant research institutes.As one of the core systems of pure electric vehicle,the parameters and control of power transmission system directly determine the driving performance of the whole vehicle and the driving experience of the driver.The first is to solve the problem that only the transmission gear ratio but not the powertrain parameters are optimized in the research process of General Electric Vehicle Powertrain Parameters Matching Optimization.By using the genetic algorithm compiled in MATLAB,taking the acceleration time of 100 kilometers and the energy consumption of NEDC working condition of the two-speed transmission model of electric vehicle built in AMESim as the dynamic and economic indexes,the power assembly parameters(driving motor speed,torque and gear ratio)in the model are optimized.After optimization,the economy and power of the whole vehicle are greatly improved,and the contradiction between economy and power is effectively balanced.The second is the development and research of the transient shift model of the powertrain of the electric vehicle with two-speed AMT transmission.Through the analysis of the shift process and state of the two-speed transmission model,AMESim software is used to establish the two-speed transmission transient dynamic model of the electric vehicle,and then through the analysis of the cooperative control among the controllers(VCU,TCU,MCU)in the transient process of the upshift and downshift,simulink software is used to establish the transient control model and complete the joint simulation.Through the simulation analysis,it is proved that the joint simulation model can effectively simulate and analyze each stage of the two-speed transmission transient upshift and downshift process of electric vehicle.The third is the optimization of shift process control based on driver intention recognition.Through the dynamic analysis of the up and down shift process of the two-speed AMT transmission,it is concluded that the vehicle jerk in the unloading and recovery stage of the driving motor torque is affected by the change rate of the motor torque.Then,in view of the shortcomings of the fixed value of the unloading and recovery rate of the driving motor torque in the traditional shift control of the electric vehicle transmission,the optimization method based on the driver intention recognition is adopted.Through the simulation analysis,it is proved that this optimization method can improve the shift quality.