Research On Shift Control Of Electric-Drive Mechanical Transmission System

Electric vehicle has the advantages of zero emission,energy saving and environmental protection.It was a potential automobile industry in the future,and also a key industry for each country to develop.The multistage transmission used in electric vehicles can widen the torque of the driving motor,make the driving motor in the high efficiency area,and improve the power and economy of the vehicle.This made the application of electric-drive mechanical transmission(EMT)become the development trend of electric vehicle transmission system.This article studied the coordinated control of drive and shift actuator of EMT system and the control method based on minimum principle,designed the special shift transmission control unit(TCU)for EMT,and tested the comprehensive performance of the shift process.Firstly,analyzed the mechanical transmission structure and shifting actuator of EMT system,and established the power transmission mode.Studied the control strategy of shifting process of EMT.In order to shorten the shifting time and improve the smoothness in the process of shifting,put forward the input and output requirements of TCU in EMT system,and determined the control scheme of shift process.Secondly,studied the double closed-loop control method of torque and speed for driving actuator of EMT system to realize fast speed regulation;studied the position closed-loop control method of gear shifting actuator to realize the position alignment of transmission engagement sleeve.Based on the above two methods,it was studied about the multi-mode coordinated control method of EMT drive and shift system.When the engagement sleeve was in neutral,the minimum principle control method was used to adjust the relative speed and rotation angle of EMT engagement ring and engagement sleeve to achieve synchronization and complete the shift process of EMT system.Thirdly,using modularization method,designed a special TCU and system software for EMT,including minimum system module,CAN communication module,input signal acquisition module,driver and shift actuator control module.The functional requirements of each module were tested,and they provided the hardware basis for shift performance test.Finally,completed the hardware-in-the-loop simulation test and real-lane road test of EMT system.The simulation and test results showed that TCU meets the requirements of accuracy,stability and reliability,and EMT system can shift gears quickly and smoothly.