LPV control of speed fluctuations in rotating machines with nonlinear dynamics

This paper presents a method for controlling torsional vibrations in rotating machines with nonlinear dynamics. The work is motivated by rotating machines with cam or crankshaft mechanisms that generate harmonic signal components in the angular speed with respect to the rotation angle. In the system description, the torsional vibrations are modeled as disturbances acting upon a linear plant. Thus, the system can be decomposed into a plant model and a disturbance model. Both models are then described as polytopic linear parameter-varying (pLPV) systems. A disturbance observer-based controller is used to counteract the time varying fluctuations in the angle speed. The method is tested in a simulation study with a model of a camshaft drive. The simulation results demonstrate the efficiency of the control approach.