Design of an active vibration control system for isolation of an optical bench

The isolation of an optical bench mounted on an airplane using active noise cancellation was studied. The most difficult problem is the necessity for isolation at low frequencies (0.1 Hz). At these frequencies, an active noise cancellation filter was necessary. An ANC filter using strain gauges (which have no rigid body component) as the reference signal was simulated with several different algorithms. The algorithms were tested under a variety of different frequency inputs and different modal frequencies of the body. A recursive least squares filter was found to give the fastest convergence and best results. A least means squares, on the other hand, gave unsatisfactory performance. It was decided to use active vibration control for this problem.<
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