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RESEARCH PRODUCT

Linearized Piecewise Affine in Control and States Hydraulic System: Modeling and Identification

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description

In this paper, the modeling and identification of a nonlinear actuated hydraulic system is addressed. The full-order model is first reduced in relation to the load pressure and flow dynamics and, based thereupon, linearized over the entire operational state-space. The dynamics of the proportional control valve is identified, analyzed, and intentionally excluded from the reduced model, due to a unity gain behavior in the frequency range of interest. The input saturation and dead-zone nonlinearities are considered while the latter is identified to be close to 10% of the valve opening. The mechanical part includes the Stribeck friction detected and estimated from the experiments. The linearization is performed in multiple steps, for the most pronounced terms of nonlinear system dynamics. Out of this follows a linearized piecewise affine in the control and state model in a state-dependent matrix form. A series of measurements were performed on the designed and implemented experimental setup, while identifying uncertain parameters of the system, in addition to those obtained from the technical data and characteristics of components. The models behavior are compared with experimental measurements and discussed.