Analysis and Control of Wet Friction Clutches for Automotive Applications**In cooperation with Magna PT B.V. Co. KG, Untergruppenbach, Germany.

摘要

This article proposes a two-degree-of-freedom control for an electro-hydraulic actuated wet friction clutch in an automotive transmission. A holistic approach is used that deals with both, the nonlinearity of the system and the switching behavior that occurs when the clutch is actuated within its complete range of motion. Hence, we analyze the system with a special focus on the controllability and observability of the actuator. Subsequently, the feedforward-part of the controller is designed with an exact feedforward linearization of a reduced clutch model. For the feedback-part a linear-quadratic regulator is proposed that is obtained by a linearization around an appropriate operating point for each of the discrete modes. For the reconstruction of the full state for the feedback controller, an extended Kalman-Filter is designed that uses the implicit Euler method, ensuring numerical stability of the stiff clutch ODEs in presence of a fixed-step simulation scenario. The performance of both, the observer and the control algorithm, is illustrated by means of simulations with a detailed model, that is typically used for the study of powertrain efficiency.