Active vibration control in a cantilever-like structure: a time delay compensation approach

Abstract

The aim of this study is to develop a method of active control based on time delay compensation for the low-order modes of a cantilever-like structure suffering from complex excitations. The time delay is induced by an anti-aliasing filter and a high-order digital low-pass filter, which are introduced to prevent frequency aliasing and observation spillover. However, approaches for time delay processing in active control systems have in the past been model dependent. This paper adopts a velocity feedback control law to increase system damping, and constructs an autoregressive moving average (ARMA) model for eliminating the time delay caused by filters. The ARMA model is model-free and its coefficients are adjusted adaptively according to the outputs of the system. In practical applications, the direct current (DC) excursion induced by the calculation is also considered, and a proper method of DC cancellation is adopted. A wind-tunnel model with rear sting is used as a cantilever-like structure in the experiments. The results reveal that the first mode vibrations of the model are effectively suppressed by this controller when the structure suffers from complex excitations.