Coordinated Engine Torque and Clutch Control During Gear-Shifting Process of Automated Manual Transmission

This paper presents a novel powertrain control system specifically designed for longitudinal motion-control applications of an automated-manual-transmission vehicle, whereby the clutch and throttle modulation and gear change are highly coordinated such that the vehicle can precisely track the target acceleration or deceleration command even during an upshift or a downshift. An observer-free method for estimation of the engine’s operating point under various working condition is developed to compensate for limited sensing and enable effective feed-forward control of the engine torque and the clutch pressure. With minor modifications of the coordination strategies in the existing powertrain control system, the proposed control system can prevent stalling the engine from a standing start and achieve smoother shifting and faster dynamic response of the powertrain system, where non-smooth actuator nonlinearities are addressed explicitly, robustly, and efficiently. As revealed through off-line simulation, the proposed control methodology brings an average decrease in the clutch-slipping duration of 35.73% with negligible loss of the motion-tracking performance, such that system reliability, driving comfort, and fuel economy of the vehicle can be guaranteed.