Suppression of Cross-Well Oscillations With Active Control of a Bistable Laminate

Abstract

Although there have been numerous efforts into harnessing the snap through dynamics of bistable structures with piezoelectric transducers to achieve large energy conversion, these same dynamics are undesirable under morphing applications where stationary control of the structure’s configuration is paramount. To suppress cross-well vibrations that primarily result from periodic excitation at low frequencies, a novel control strategy is proposed and implemented on the piezoelectrically generated bistable laminate, which consists of only Macro Fiber Composites (MFC) in a [0MFC/90MFC]T layup. While under cross-well regimes such as chaotic or limit cycle oscillations, a single MFC is actuated past the laminate’s limit voltage to eliminate one of its potential wells and force it into the remaining stable state. Simultaneously, a Positive Position Feedback (PPF) controller suppresses the resulting single-well oscillations through the other MFC. This dual control strategy is demonstrated with an electromechanical model through the suppression of various cross-well regimes, and results in significant reduction of amplitude. The active control capability of the laminate prevents snap through instability when under large enough external vibrations and adds to its multifunctionality along with morphing and broadband energy harvesting.