Hierarchical mode optimization strategy for gear engagement process of automated manual transmission with electromagnetic actuator

Abstract

When vehicles equipped with automated manual transmission (AMT) are in the gear engagement process (GEP), the problems of longitudinal shift jerk and synchronizer wear deterioration is prominent, which seriously affects the GEP quality. This paper develops and evaluates a hierarchical mode optimization strategy (HMOS) for GEP. Firstly, the models of gear-shift actuator and three-stage GEP are established, and the correlation between sleeve displacement and cone torque is revealed based on the established models. Next, the HMOS is proposed for cone torque optimization and sleeve trajectory tracking during GEP. At the top layer of the HMOS, a novel sliding-mode predictive controller (SMPC) with constraints is proposed for the cone torque decision during the synchronization stage of the GEP. At the bottom layer of the HMOS, an MPC-based sleeve trajectory tracking controller integrated with a load torque disturbance observer (L-DOB) is presented. Finally, the simulation and hardware-in-the-loop (HIL) test are carried out in a driving condition of power upshift from the first gear to the second gear to verify the performance of the optimization strategy. The verification results show that the proposed optimization strategy achieves satisfactory longitudinal shift jerk, synchronizer sliding work, and thermal stress.

Research on Precise Tracking Control of Gear-Shifting Actuator for Non-Synchronizer Automatic Mechanical Transmission Based on Sleeve Trajectory Planning

“…The comparison between simulation and experimental results validates the effectiveness of the proposed control approach, offering a novel solution for AMT gear-shifting systems. The authors of a study (Tao P et al [16]) developed a hierarchical pattern optimization strategy (HMOS) for AMT gear junction, wherein GEP models were established for the shift actuator and three stages to reveal the In the examination of the AMT shift process, scholars have generally categorized it into six stages [1,8,9] and provided detailed descriptions and analyses for each stage. The conventional AMT shift control involves the engagement of the target gear by the shift actuator after the completion speed adjustment (when the difference between sleeve speed and target gear speed reaches a certain threshold).…”

“…The comparison between simulation and experimental results validates the effectiveness of the proposed control approach, offering a novel solution for AMT gear-shifting systems. The authors of a study (Tao P et al [16]) developed a hierarchical pattern optimization strategy (HMOS) for AMT gear junction, wherein GEP models were established for the shift actuator and three stages to reveal the relationship between sleeve displacement and friction cone torque. At the top layer of the HMOS, a novel sliding mode predictive controller (SMPC) with constraints was proposed for making tapered torque decisions during the GEP synchronization phase.…”

“…Due to the absence of a unified dynamic model in the conventional AMT, it is commonly analyzed in multiple stages [13,16]. Naunheimer et al [25] categorized this process into five stages and provided comprehensive explanations for each stage.…”

MPC-Based Coordinated Control of Gear Shifting Process for a Power-split Hybrid Electric Bus with a Clutchless AMT

“…The speed synchronization process of the synchronizer is an important link in the shifting process. In most articles, the contact reaction force generated between the locking ring and the gear ring during the synchronization stage is a constant value, and the resulting friction torque, namely, the synchronization torque, is a constant value [29,30]. However, in fact, contact reaction force during synchronization is a complex process that gradually increases from 0 to shift force [31,32].…”