A study on controller structure interaction of piezoelectric smart structures based on finite element method

The control of piezoelectric smart structures described by large-scale finite element models typically requires construction and use of reduced-order models for the purpose of feedback controller design and implementation. However, reduced-order model–based controllers can have deleterious interactions with unmodeled modes. The unwanted controller structure interaction can cause performance degradation and even instability. The concern is that the controller structure interaction is seldom considered in conventional vibration control study of piezoelectric smart structures. In this article, a general framework within which one can study the effect of controller structure interaction is developed by integrating the reduced-order model–based controller into finite element environment. The issue of controller structure interaction is then examined numerically. The importance of including controller structure interaction effects in closed-loop simulation of piezoelectric smart structures is demonstrated. It is shown that the conventional controller design approach is very much influenced by the order of reduction of the piezoelectric smart structure. This suggests that for piezoelectric smart structures in which controller structure interaction is significant, application of the conventional control system design methods may not be adequate. Moreover, examples of controller structure interaction–induced spillover are illustrated via power spectral density of the displacement response.