Research On Shift Control Strategy Of Direct Drive AMT Based On Shift Schedule

With the rapid development of the pure electric vehicle industry,the multi-stage pure electric vehicle power transmission system with high-efficiency and energy-saving characteristics has attracted the attention of the majority of scholars.In this paper,the two-speed direct-driving AMT(Direct-Driving Automated Mechanical Transmission)As the research object,the shift schedule and shift process control strategy of a pure electric vehicle equipped with DAMT are studied.In order to further shorten the shift time of DAMT,a motor-synchronizer joint synchronous shift process control is proposed.Strategies,taking into account the effects of shifting rules and shift process control strategies on vehicle performance,respectively formulating dynamic shifting patterns,economical shifting patterns,and driver-based driving styles that can take into account vehicle dynamics and economic performance Recognizing the shift mode has laid the foundation for the application of DAMT in pure electric vehicles.The specific work of this paper mainly includes the following aspects:(1)Parameter matching and optimization of power transmission system based on two-speed DAMT.Based on the vehicle parameters of a certain pure electric vehicle,a series of power performance indicators were formulated,and the DAMT two-gear transmission ratio range was calculated on the basis of completing the matching of driving motor parameters.A simulation model of vehicle driving energy consumption was established,and the optimization goal was the lowest vehicle driving energy consumption in a WLTC cycle.The mode FRONTIER optimization software and Simulink simulation model were used for joint simulation optimization,and the vehicle economic performance was optimal under the constraint conditions.The twospeed transmission ratio.(2)The shift schedule is formulated based on the two-gear DAMT.Based on the two-gear DAMT,the shifting rules under the optimal economic performance and power performance of the vehicle were formulated,and the shift controller was established based on MATLAB/Stateflow.The simulation results of the whole vehicle showed that the shifting logic of the shift controller was accurate.When the best power shift schedule is adopted,the vehicle takes 12.97 s during the 0～100km/h acceleration process.Compared with the best economic shift schedule,the entire acceleration process time is shortened by 5.78%;when the most In the best economical shift schedule,the energy consumption of the vehicle in a WLTC cycle is 3.137 k W·h,which is 3.2% lower than the optimal shift schedule in dynamics.(3)Research on the control strategy of DAMT shift process.A detailed analysis of the DAMT shifting process when using the synchronizer synchronous shift control strategy and the motor speed synchronous shift control strategy is carried out.In order to further shorten the DAMT shift time,a motor-synchronizer joint synchronization is proposed.The gear shifting process control strategy of the company compares and analyzes the shift quality of DAMT under the three shift control strategies.Simultaneously with the simulation analysis,a DAMT general test platform is built.The test results show that: when the shift speed difference is 1050r/min,When the joint synchronous shift control strategy is adopted,the shift synchronization time is0.22 s.When the motor speed control synchronous shift control strategy is adopted,the shift synchronization time is 0.36 s.The joint synchronous shift control strategy shortens the shift synchronization time.38.8%,verifying that this shift control strategy can effectively shorten the DAMT shift time.(4)Research on the comprehensive control of shifting,considering the shifting schedule and the control strategy of the shifting process.The influence of the shifting process on the vehicle’s power and economy performance is studied,and two shifts of power and economy are formulated according to the vehicle’s power and economy performance under different shifting process control strategies and different shifting rules.The simulation results show that the 0～100km/h acceleration process of the vehicle in the dynamic shift mode takes 13.21 s,of which the shift time is 0.29 s,and the acceleration process time is shortened by 6.9% compared with the economic shift mode;The energy consumption of the vehicle in a WLTC cycle of the dynamic shift mode is3.146 k W·h,of which the driving energy consumption accounts for 3.137 k W·h,and the shift energy consumption accounts for 37.28 kj,which is higher than the vehicle energy consumption in the dynamic shift mode Reduced by 3%.In order to solve the problem that the two shift modes cannot take into account the power and economy of the vehicle,a fuzzy controller that can recognize the driving style of the driver is built.The simulation results of the whole vehicle show that the shift mode can be recognized based on the driving style.Under the premise of accurately identifying the driving style of the driver,the goal of taking into account the power and economy of the vehicle is achieved.