Abstract:To improve the shifting quality of the automated manual transmission (AMT), a type of AMT gearshift system based on a 2-DOF electromagnetic actuator was developed. A coupling system model including electric, magnetic circuit and mechanics was built. The characteristics were investigated through tests. The output force was more than 1200N and the maximum output torque was 2.5N·m, which showed that the dynamic response was relatively fast. The gearshift process was divided into four phases. During the synchronization process, an optimal objective function of shift quality indexes was developed and the optimal control was adopted to achieve the optimal shift quality. The shift sequence coordinated control of shift out and gear selection was introduced, and the gearshift controller was designed and tested. When the equivalent inertia was 0.03kg·m2 and the speed difference was 620r/min, the results showed that the shift time was 135ms, the impact was 3.86m/s3, and the friction work per unit was 0.077J/mm2. The coordinated control method could be reduced to 11ms. The test results indicated that, combined with the designed control strategy, the novel gearshift system achieved good shift performance.