Control design for a reduction of clutch judder in a truck drive train

This paper presents a comparison of two alternative control structures for an active oscillation damping of truck drive trains. Uncomfortable oscillations in the drive train may occur in phases when the dry clutch is slipping. The negative friction coefficient of the clutch lining could cause an undesired judder, which leads to a severe driver discomfort. At first, a control-oriented model is derived by a step-by-step simplification. The first control design consists of a model-based approach that uses a feedback of the relative angular velocity for a reduction of the oscillation amplitudes. Despite a measurement of the angular velocity at the drive side, this value is usually not available for the transmission control unit. Therefore, a modified Utkin sliding mode observer is employed that estimates the state vector as well as a disturbance torque. In the second approach, a simple feedback of the angular velocity signal at the clutch side is used for an active damping of torsional oscillations in the truck drive train. Both control approaches are validated at a dedicated test rig at the Chair of Mechatronics, University of Rostock.