Robust control techniques for adaptive optic space telescopes

Abstract

Future space telescopes will contain lightweight, flexible, segmented mirrors. Traditional control approaches for mirror alignment and shape control may be inadequate due to flexibilities and low natural frequencies. Using adaptive optics for space telescopes presents a possible solution. This research proposes H∞ robust control techniques for these types of systems. An H∞ controller is synthesized for a complex analytical model. This was accomplished with a new technique for model reduction using Zernike polynomials. The H∞ design process used was validated on a simpler adaptive optics testbed. The experimental verification also showed that the robust control techniques outperformed the classical control techniques in the presence of disturbances. The results are a Zernike polynomial method for model reduction, robust controller synthesis for a complex adaptive optics analytical model, and experimental verification on an AO testbed. Although the robust control design is more complex, it provides improved performance in the presence of uncertainty in the disturbances and modeling.12