Broadband active structural damping using positive real compensation and piezoelectric simultaneous sensing and actuation

The use of piezoelectric elements as a means for implementing broadband, low authority structural control with passive and active electrical impedance matching is investigated. Passive techniques are shown to be ineffective for truly broadband problems due to the relatively large inherent piezoelectric capacitance. Active techniques are developed using the simultaneous sensing and actuation (SSA) circuit. Detailed analysis of circuit tuning issues in conjunction with mechanical boundary conditions of the piezoelectric element is presented. The result is a set of guidelines for SSA component selection to enable the implementation of guaranteed stable positive real feedback for damping enhancement. Examples and experimental results on the SERC Interferometer Testbed are presented. Difficulties in implementation presented by the unmodeled piezoelectric losses and nonlinearities, which prove to be significant when using axially stacked elements, are discussed. (Author)