Abstract
The potential advantages of lightweight, compact and easily attacheable or embeddable induced strain actuators can be quickly overshadowed by the bulky power supplies, electronics and controls necessary to drive them. Previous work in power and control has used circuit-theoretic concepts to combine the control system design process with energy flow analysis. This is extended here to encompass thin plates with multiple attached piezoelectric devices, providing the basis for an integrated theory of high-efficiency active control with piezoelectric elements. A major result is that, while good broadband vibration suppression and damping require active control, this does not imply that the control consumes net energy. In addition to the usual division into passive and active control, therefore, a third possibility of active, zero-energy control (termed quasi-active control) arises.