Analysis and optimization of the gear-shifting process for automated manual transmissions in electric vehicles

Abstract

In recent years, it has been a trend for an automated manual transmission to be adopted as the powertrain for an electric vehicle. However, the strong degrees of jerk and power interruption during the gear-shifting process affect the shifting quality and restrict the application of automated manual transmissions. Therefore, it is a currently popular research topic to find an optimal method to improve the shifting qualities of automated manual transmissions. In this paper, the clutchless shifting process is analysed on the basis of a dynamics model of an automated manual transmission in an electric vehicle, and the parameters are optimized to improve the shifting quality using a defined comprehensive evaluation index. First, the dynamics model of the shifting process for an automated manual transmission is established by considering the stiffness, the damping and the non-linearity contact backlash of the gear mesh and the synchronizer. The whole shifting process is carried out in MATLAB/Simulink and compared with that in the Adams model and bench experiments to prove the accuracy of the dynamics model. Then, the factors of the shifting quality, which include the shifting force and the control accuracy of the speed of the driving motor, are quantified. With the comprehensive evaluation index, all the main factors are described in a cobweb model diagram to find the optimal parameters of the shifting process. The results show that the comprehensive evaluation index can be reduced by 23% by regulating the parameters of the shifting process. This study may be conducive to improving the shifting quality of automated manual transmissions in electric vehicles.

Minimizing synchronization time of a gear shifting mechanism by optimizing its structural design parameters

“…The gear shifting process is modeled in MATLAB/ Simulink. 6 The model is verified with the Adams model and validated with experimental data. Parameters of the gear shifting mechanism are optimized based upon the quality measures which are the shift force and control accuracy of the driving motor speed.…”

Synchroniser control with proportional pressure reducing valves and displacement feedback

“…The dual-clutch transmissions developed fast these years. 1,2 With the high transmission efficiency, it can satisfy the fuel economy requirement. Further, more speed ratios and a wider speed range can also be achieved.…”

Multi-Stage Gear Shifting Control Scheme for Electric Mechanical Transmission: Design and Experiment

“…Electric mechanical transmission (EMT) is basically an mechanical transmission (MT) with the integration of electromechanical actuator [1], [2], which combines the high efficiency, low cost of traditional MT, with the convenience of automated transmission (AT) [3]. Two key technologies of EMT are the clutch control and gear shifting control [4], [5].…”