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The problem of active control in linear elastic structures with piezoceramic actuators has been investigated using both a theoretical and experimental approach. An active structure consisting of a simple beam element with a bonded piezoceramic actuator and a strain gage as sensor has been made. To model the active estructure for maximum increase in system damping, a simple finite element model has been taken from the classic literature. The model incorporates the electromechanical coupling of the transducers as well as bonding effects. The model control has been experimentally demonstrated by conditioning the output of the sensor with a data acquisition system and a digital signal processing that implements adjustable bandpass filtering, fast Fourier transform for real time spectrum estimation and the cancellation algorithm that supplies the voltage reference to the boost circuit that provides the high voltage level required by the piezoactuator. The experiment primarily consisted of investigating the behavior and performance of the individual unimorph transducer, analysis of the active estructure behavior and searching the best cancellation strategy. Focus has been pointed on some special characteristics of piezoelectric elements, such as their dynamic behavior, as well as the digital signal processing for fast modal frequencies identification avoiding the pitfalls of aliasing and spectral leakage by means of the design of a real multirate system. The active damping augmentation in the low frequency range of flexible beam-shaped structures makes it suitable for placement of electro-optical devices where high-precision pointing is an essential feature. The time reduction to stabilize the structure, that is total vibration cancellation, demonstrates that the piezotechnology is a powerful means to increase the performance of a mechanical structure.
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