A Nonlinear Block-Oriented Model for Wind Tunnel System
Keywords: Wind tunnel system, block-oriented model, pseudo-Hammerstein model, recursive identification
AbstractThis paper develops a novel nonlinear block-oriented model for the wind tunnel system. Based on the available signals, the wind tunnel system can be divided into three parts, namely, the exhaust valve loop, the choke finger loop and the flow field. Then the considered plant is described as a nonlinear block-oriented model. The exhaust valve subsystem and the flow field subsystem are both expressed by linear dynamic models, whereas the choke finger subsystem exhibits a nonlinear characteristics and is approximated by a pseudo-Hammerstein model. Based on the above parameterization model, the recursive identification algorithms are presented for three subsystems. Interestingly, the adaptive weighted recursive least squares algorithm is applied to the pseudo-Hammerstein model, and the hierarchical recursive least squares algorithm is used to reduce the computational complexities. Both simulations and experiments are carried out to verify the effectiveness of the proposed method.
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