CONTINUOUS SLIDING MODE CONTROL OF FLOW-INDUCED VIBRATIONS

Vortex-induced vibrations of flexible circular cylinders and galloping oscillations of square prisms are controlled using a robust continuou s sliding mode (CSM) controller. The ability of the CSM controller in rejecting the pow-induced disturbances and accommodating parameter unc ertainties is numerically demonstrated. In the present study, emphasis is placed on the development of theoretical models that describe the inter action between the flexible structures, the flow-induced excitat ion, and the CSM controller. In our development, the vortex-induced vi brations are based on the lift-oscillator model of Hartlen and Currie and the galloping phenomenon is described using Parkinson and Smith's model. The effectiveness of the CSM controller in suppressing the pow- induced vibrations of cylinders and square prisms is evaluated at vari ous flow conditions and levels of structural uncertainties. The effect of the design parameters of the CSM controller on its performance is also investigated. Tl?he results obtained in the study suggest the pot ential of the robust control strategy presented as an important tool f or rejecting undesirable and unmeasurable disturbances acting on criti cal structures that have considerably large parameter uncertainties. ( C) 1995 John Wiley & Sons, Inc.