Optimal Sensing/Actuation Strategies for Vibration and Acoustic Control of Optical Systems

Optical jitter can result in the beam pointing inaccuracy and poor optical system performance. With a correlated measurement of the disturbance, improved control performance can be achieved. In this research, an adaptive optimal sensing strategy for optical systems is proposed. When an array of reference sensors is available, an optimal set of reference sensors that are coupled to modes of interests can be selected. The weighted reference signal from the optimal sensor set is then used in an adaptive control design algorithm. An adaptive generalized predictive control design algorithm combined with the proposed adaptive optimal sensing strategy achieves better performance than the control system using only one of the reference sensors. The overall algorithm is also advantageous in the presence of time-varying or uncertain disturbances. The proposed technique is applied to an experimental test bed in which multiple accelerometer sensors measure the structural vibration of optical elements. Reduction of the structural vibration of optical components is attained using a fast steering mirror which results in a reduction of the corresponding jitter.