This paper discusses the use of eigenspace techniques for the design of an active flutter suppression/gust load alleviation system for a hypothetical research drone. One leading-edge and two trailing-edge aerodynamic control surfaces and four sensors (accelerometers) are available for each wing. Full-state control laws are designed by selecting feedback gains which place closed-loop eigenvalues and shape closed-loop eigenvectors so as to stabilize wing flutter and reduce gust loads at the wing root while yielding acceptable robustness and satisfying constraints on rms control surface activity. These controllers are realized by state estimators designed using an eigenvalue placement/eigenvector shaping technique which results in recovery of the full-state loop transfer characteristics. The resulting feedback compensators are shown to perform almost as well as the full state designs. They also exhibit acceptable performance in situations in which the failure of an actuator is simulated.
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Acknowledgments The research reported in this paper was partially supported by NASA Langley Research Center under Grant NAG-1-217 with Mr. William M. Adams as technical monitor, by NSF Grant DMS-8413129, and by a grant from the Academic Com-puter Center of the University of Minnesota. References ^bel, I., Newsom, J.R., and Dunn, H.J., "Application of Two Synthesis Techniques for Active Flutter Suppression of an Aeroelastic Win2 d Tunnel Model," AIAA Paper 79-1633, Aug. 1979. Schmidt, O.K. and Chen, T.K., "Frequency Domain Synthesis of a Robust Flutter Suppression Control Law," Journal of Guidance, Control, and Dynamics, Vol. 9, May-June 1986, pp. 346-351. 3Newsom, J.R., "Control Law Synthesis Using Optimal Control Theory," Journal of Guidance and Control, Vol. 2, Sept.-Oct. 1979, pp. 388-394.