Observer-based control of an electro-pneumatic clutch using extended linearisation techniques

This paper presents a non-linear model-based control design for an electro-pneumatic clutch for heavy trucks, which is required at start-up or during gear shifts to disconnect the combustion engine from the gear box. This automated actuator disburdens the driver and provides the necessary actuation force according to the large torque transmitted through the power train. The proposed control structure consists of a combined gain-scheduled feedforward and feedback control law with the clutch position as controlled variable, which are both designed based on extended linearisation techniques. A reduced-order observer estimates the internal pressure and contributes to steady-state accuracy. Moreover, a recursive least-squares estimation is used within a disturbance compensation scheme. Thereby, high tracking accuracy is achievable for the piston position as controlled variable. The efficiency of the proposed control structure is demonstrated by experimental results from a dedicated test rig.