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.