Robust Suppression of Noise in Precision Equipment

The problem of suppressing acoustically induced vibration in precision equipment is addressed. The study specifically addresses acoustically induced vibration in an airborne optical train. Two approaches will be studied. (1) The first approach is to inertially instrument each optical element, sensing the motion causing optical jitter. The array of vibration measurements are used with a robust feedback control law and with an adaptive feed forward algorithm to precisely cancel the optical jitter. (2) The second approach is to adapt an SVS active sound barrier concept to the airborne problem. The active sound barrier uses a combination of feed back and adaptive feed forward control to attenuate the sound passing through the barrier. For both approaches, robust control will be applied to the multiple input, multiple output feed back problem. Also advanced techniques of multiple input, multiple output adaptive feed forward control will be evaluated. Performance improvements will be determined using acoustic simulation. Cost for the various approaches will be developed. Based on the risk, cost, and performance benefits, a proof of concept experiment will be defined for the Phase II effort.