Active Flutter Control using Discrete Optimal Constrained Dynamic Compensators

A method for synthesizing digital active flutter suppression controllers using the concept of optimal output feedback is presented. A recently developed convergent algorithm is employed to determine constrained control law parameters that minimize an infinite-time discrete quadratic performance index. Low-order compensator dynamics are included in the control law and the compensator parameters are computed along with the output feedback gain as part of the optimization process. An input noise adjustment procedure is used to improve the stability margins of the digital active flutter controller. Results from investigations into sample rate variation, prefilter pole variation, and effects of varying flight conditions are discussed. The study indicates that a digital control law which accommodates computation delay can stabilize the wing with reasonable rms performance and adequate stability margins.

[1]  E. Kreindler,et al.  Model-following in linear-quadratic optimization , 1976 .

[2]  Michael Athans,et al.  Gain and phase margin for multiloop LQG regulators , 1976, 1976 IEEE Conference on Decision and Control including the 15th Symposium on Adaptive Processes.

[3]  G. Stein,et al.  Robustness with observers , 1978, 1978 IEEE Conference on Decision and Control including the 17th Symposium on Adaptive Processes.

[4]  B. Kurtaran.  Suboptimal control for discrete linear constant stochastic systems , 1975 .

[5]  T. Johnson,et al.  Invariants of optimal minimal-order observer-based compensators , 1976 .

[6]  J. Tyler.  The characteristics of model-following systems as synthesized by optimal control , 1964 .

[7]  M. Athans,et al.  Optimal limited state variable feedback controllers for linear systems , 1971 .

[8]  John R. Broussard,et al.  Investigation and appreciation of optimal output feedback. Volume 1: A convergent algorithm for the stochastic infinite-time discrete optimal output feedback problem , 1981 .

[9]  Thomas E. Noll,et al.  Wing/Store Flutter Suppression Investigation , 1981 .

[10]  John W. Edwards,et al.  Active Flutter Control Using Generalized Unsteady Aerodynamic Theory , 1978 .

[11]  J. R. Newsom,et al.  Reduced-Order Optimal Feedback Control Law Synthesis for Flutter Suppression , 1982 .

[12]  Alper K. Caglayan,et al.  A separation theorem for the stochastic sampled-data LQG problem. [control of continuous linear plant disturbed by white noise] , 1976 .

[13]  C. R. Stone,et al.  Control Law Synthesis for Flutter Suppression Using Linear Quadratic Gaussian Theory , 1981 .

[14]  Jerry M. Mendel,et al.  On the design of optimal time-invariant compensators for linear stochastic time-invariant systems , 1975 .

[15]  T. Rajagopalan,et al.  Algorithms for the computation of optimal output feedback gains , 1979, 1979 18th IEEE Conference on Decision and Control including the Symposium on Adaptive Processes.