Research On Optimal Control Of Driving Efficiency In Two-speed AMT Pure Electric Vehicle

With the strong guidance of the policies on the development of the new energy vehicles,major auto companies are rushing to invest heavily in researching and developing the new electrical vehicles.As pure electric vehicles have the advantages of low noise,no pollution and simple structure,they are widely concerned by government decision-making departments,business circles and academia.However,most pure electric vehicles assembled single-main reduce on the market,which resulted in a reduction in the motor's efficient operating range and a decrease in output power.The adoption of a two-speed transmission can effectively reduce the requirements for the performance of electric vehicles and extend the driving range.Therefore,it is of great significance to study two-speed pure electric vehicles.This article uses the pure electric vehicle equipped with the DCT(Double Clutch Transmission)as a prototype,to match and optimize the parameters of the power transmission system in a two-speed AMT(Automated Mechanical Transmission)pure electric vehicle.And then,The method of torque estimator based on UKF-H? driveshaft is designed,and the vehicle drive control strategy and shift control strategy are formulated.The main research content of this article is as follows:(1)According to the design requirements of two-speed AMT pure electric vehicles,calculating and matching the parameters of power transmission system.Afterwards,Based on the AMESim/Simulink simulation platform,a complete vehicle model is built,which include a driver model,a battery model,a motor model,a transmission system model,and a complete vehicle longitudinal dynamic model.(2)Rational using the motor characteristics,designing the optimal dynamic shift law,adapting the entire vehicle dynamic design index as a constraint condition,utilizing a multi-objective genetic algorithm to match the optimization of motor peak power and peak torque.The optimal economic shift schedule was designed to optimize the power consumption of the vehicle's overall operating conditions.The global genetic algorithm was used to optimize the transmission ratio of the transmission and the final drive.The simulation results show that,compared with the optimization,the driving range of the optimized NEDC operating conditions has increased by 0.31%,and the driving range of the HWFET operating conditions has increased by 1.44%.(3)In order to achieve the smooth shift control of two-speed AMT pure electric vehicle,a design method based on the UKF-H? torque estimator of the drive shaft was designed to suppress the interference of the measurement noise on the accuracy of the drive shaft torque estimation.A MATLAB/Simulink simulation model was built to verify the correctness of the designed torque estimation method of the drive shaft,the testing on acceleration conditions,acceleration,deceleration conditions and shift conditions was established to the effectiveness of this strategy.(4)Analyzed the composition of the control strategy of the whole two-speed AMT pure electric vehicle.Afterwards,formulated the drive control strategy and shift control strategy.In order to improve the driving efficiency of the vehicle and optimize the motor working interval,the shift curve is corrected and the accelerator pedal response curve is modified and optimized.The simulation results show that the shift curve and throttle pedal response curve modification strategy have little impact on the vehicle's dynamic performance,but have a great influence on the overall vehicle economy.To a certain extent,with the gradual acceleration of the accelerator pedal,the vehicle continues to drive.Mileage increases gradually.The optimized energy consumption minimization optimization strategy can accurately obtain the economical optimal accelerator pedal response curve.Simulations verify the effectiveness of the strategy and the vehicle driving range has been significantly improved.