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Reduced Order Modelling and Control of an Electrohydraulic Valve System
Published April 19, 2004 by University of Salerno in Italy
In novel combustion strategies like HCCI, fully flexible inlet and exhaust valves in terms of lift and timing are required to enable HCCI. In this paper, we explore issues related to control of an electrohydraulic variable valve system. A nonlinear model of an electrohydraulic valve system is linearized and simplified to a reduced order model to overcome numerical stability issues. A model-based control algorithm is developed based on the reduced order model. The control algorithm consists of an observer to estimate the unmeasurable states and the disturbance acting on the plant, and permits tracking of any sufficiently smooth-bounded trajectory. Numerical simulations and experimental results are presented for a sine wave and for a partial lift profile to indicate the effectiveness of the control algorithm developed.