Speed control for automated manual transmission with dry clutch

Automated manual transmissions (AMTs) with dry clutches are becoming more and more used as an improving add-on solution on classical manual transmission systems and as a reconfiguration element in modern hybrid electric vehicles. Due to the two possible states of the clutch (engaged or not) and to the different gear ratios AMTs can be considered as a particular class of the hybrid systems. The paper presents a gearshift control strategy for modern AMTs. Models of the driveline, of an electrohydraulic engagement actuator and of the dry clutch are detailed and tuned on experimental data. The controller is designed through a hierarchical approach by discriminating among five different AMT operating conditions: engaged, slipping-opening, synchronization, go-to-slipping and slipping-closing. Three cascaded feedback loops are designed respectively on speeds, torques and throwout bearing position. Simulation results on a gasoline 2.4 FIAT STILO car show the effectiveness of the proposed controller.