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 fi nite-element model of a cantilever beam and laser sensing showed that if th e laser can be scanned faster than the highest natural frequency of the bea m, and all the velocity states are measured, the performance of classical l inear optimal control can be approached. To further verify the technique, a n experiment using a cantilever beam structure was built and the laser sens or was tested along with other types of sensors. In the experiments, only t he first vibration mode of the cantilever beam was controlled because of a limitation in the speed of the scanning mirror used. The testing showed tha t a hybrid-sensing technique in which the laser and a piezoceramic patch ar e used simultaneously for sensing, and separate piezoceramic patches are us ed for actuation, was a very effective approach for vibration suppression. Although laser sensing requires expensive components, the technique propose d can be used for the control of structures that are large, inaccessible, r equire non-contact sensors, or when a large number of coordinates must be m easured. (C) 2000 Academic Press.