Gear Shifting Control For 2-speed AMT Without Power Interruption In Pure Electric Vehicle

With the development of electric vehicles,the transmission for electric vehicles has received more and more attention.Due to the high requirements of electric vehicles for driving comfort,the shift quality of electric vehicle transmissions is particularly importantAMT(Automated Manual Transmission)is increasingly used in pure electric vehicles due to its low cost and high efficiency.Traditionally,AMT-matched vehicles usually adopt a rule-based shift control method.In this way,a large number of calibrations are required to ensure their shift quality.And due to internal and external uncertain factors during driving,it is difficult to achieve the optimal shift quality in various operating conditions based on calibration.Therefore,this paper uses model-based control to ensure shift quality under various operating conditions while avoiding a lot of calibrationIn this paper,an I-AMT(Inverse Automated Manual Transmission)is taken as the research object.In order to improve its shift quality,a transmission dynamic model is established and an optimal controller is designed.Then the performance of this controller is proved through simulation and tests.The specific work of this article is as follows1.The overall structure and arrangement of I-AMT,the working principle of overrunning clutch and shift actuator are introduced.The power transmission routes of its first and second gears is elaborated,and it is explained why this transmission can realize shifting without power interruption.Then the key of shifting without power interruption and improving shifting quality is pointed out.This article divides the shifting process into four stages:idle stage,moment phase,inertia phase,and actuator homing.Propose control strategy for each stage,and point out the control of inertia phase is the key to improving the shift quality2.The dynamic model of the transmission in the inertia phase is established Based on the LQR(Linear Quadratic Regulation),considering external and internal vehicle disturbances,a disturbance term is introduced and a disturbance suppression control law is derived.Since the disturbance term cannot be measured by sensors,a disturbance observer is designed to improve the robustness of the controller.3.The vehicle and controller were modeled and simulated in Simulink.The simulation conditions are up shifting and downshifting under constant and varying acceleration pedals,and the control strategies of optimal control and open loop control are selected for comparison.Simulation results show that the proposed control strategy can improve the shift quality of I-AMT4.A test platform is built,the automatic transmission control unit(TCU)and the PC software are designed,and a shift test of the real vehicle is conducted.The conditions are upshifting at different accelerator pedal depths and downshift at maximum accelerator pedal depths.The results show that the shifting time is within a reasonable range,and the shifting jerk meets the requirements of driving comfort,which proves the effectiveness of the control strategy proposed in this paper.