Direct-Drive Rotary-Linear Electromechanical Actuation System for Control of Gearshifts in Automated Transmissions

A direct-drive electromechanical actuation system has been developed which acts directly on the shift rails of either an automated manual transmission (AMT) or a dual clutch transmission (DCT) to facilitate gear selection. Direct-drive electromechanical actuation schemes offer a number of advantages over electric motor and gearbox systems in that they have reduced mechanical hysteresis, backlash and compliance, have fewer components, are more robust, and exhibit a better dynamic response. A high-force, moving-magnet linear actuator is combined with a moving-magnet rotary actuator to enable multi-axis control and, hence, enable the selection of all transmission ratios. The measured and predicted static performance of the rotary actuator, and the dynamic performance of the combined rotary- linear actuator, mounted on a gearbox test rig, are presented.