ADAPTIVE FEEDFORWARD CONTROL FOR ACTIVELY ISOLATED SPACECRAFT PLATFORMS

Active vibration isolation systems are being considered to improve the performance of spacecraft instruments and sensors. Because of uncertainties inherent in on-orbit operation, adaptive control strategies and algorithms have relevance to these systems. In this paper, analysis of the algorithms, numerical simulation, and laboratory test data are used to evaluate adaptive feedforward control. Of particular interest are performance characteristics and limitations of the filtered-x LMS (FXLMS) algorithm and its finite impulse response (FIR) filter implementation. Combination feedback/feedforward control and the Augmented Error algorithm are two means investigated to extend the capabilities of FXLMS by desensitizing the algorithm to the specific dynamics of the plant. Several experiments were conducted on a laboratory testbed which serves as the prototype for a planned active vibration isolation flight demonstration.

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