VIBRATION SUPPRESSION USING A LASER VIBROMETER AND PIEZOCERAMIC PATCHES

A new vibration suppression technique is investigated that uses a scanning laser Doppler vibrometer to measure structural velocities for feedback in a control system. Piezoceramic patches are used for control actuators and to measure strains for feedback in the control system. Simulations using a finite-element model of a cantilever beam and laser sensing showed that if the laser can be scanned faster than the highest natural frequency of the beam, and all the velocity states are measured, the performance of classical linear optimal control can be approached. To further verify the technique, an experiment using a cantilever beam structure was built and the laser sensor was tested along with other types of sensors. In the experiments, only the first vibration mode of the cantilever beam was controlled because of a limitation in the speed of the scanning mirror used. The testing showed that a hybrid-sensing technique in which the laser and a piezoceramic patch are used simultaneously for sensing, and separate piezoceramic patches are used for actuation, was a very effective approach for vibration suppression. Although laser sensing requires expensive components, the technique proposed can be used for the control of structures that are large, inaccessible, require non-contact sensors, or where a large number of coordinates must be measured.