Power Uninterrupted Gear Shift Control Of Two-Speed AMT In Pure Electric Vehicle

With the exhaustion of resources and increasingly serious environmental problems,more and more attention has been paid to the development of green and environmentally friendly modes of transport,the market share of pure electric vehicles is increasing constantly.Pure electric vehicles with gearbox can obviously improve the high-speed acceleration performance and efficiency.Compared to the traditional internal combustion engine vehicles,pure electric vehicles are more rigorous for shift quality of gearbox on count of the strong speed control capability of motor.Therefore,improving the shift quality of the pure electric vehicle gearbox is an urgent task to be completed.This paper is related to a two-speed gearbox based on a overrunning clutch and a friction clutch,aiming to improve the shift quality,the shift control strategy is concluded through dynamics analysis,simulation modeling and vehicle experiments,the results of simulation and vehicle experiments show that the shift control strategy can reduce the shift jerk,ensure the shift without power interruption,and guarantee the shifting time and the work of sliding friction in a reasonable range,the details of this paper are as follows:First,Structure introduction and theoretical analysis.Firstly,the structure of I-AMT and the working principle of overrunning clutch are introduced,the power gearbox routes under different gears are analyzed.The dynamic model of shifting process is established,the shifting process is analyzed to explain the principle of upshift without power interruption,the downshift process is discussed and the reasons for the possible power interruption during the downshift process are analyzed.Second,Vehicle modeling and simulation.Build the vehicle model by Simulink/SimDriveline,which includes motor,I-AMT gearbox,electric clutch actuator,shift simulation results verified the correctness of the theoretical analysis results and show shift jerk and downshift power interruption need to be solved.Third,Control strategy and simulation verification.During the upshift process: according to the different states in the clutch combination process,the reference position of friction cutch in the upshift process is established;during the downshift process: keep the friction clutch sliding to guarantee power output,adjusts the output torque of the motor to make the rotation speed of the inner and outer rings of the overrunning clutch sync smoothly at the same time.To ensure the position tracking control performance of the friction clutch,design the feedforward-feedback controller to reduce the impact of system nonlinear factors;the performance of the control algorithm is verified in the simulation platform.The last,Vehicle experiment.The signals of vehicle and gearbox are obtained and processed,the DSPACE-MicroAutobox is used for vehicle experiment,the experiment results show that the control strategy can guarantee shift without power interruption and improve the shift quality,after the parameters are tuned by MicroAutobox,the control program is converted into C code automatically,then the C code is integrated with Underlying driver code for vehicle real-time operation.