ROBUSTNESS EVALUATION OF A FLEXIBLE AIRCRAFT CONTROL-SYSTEM

The structured singular value analysis technique is used to generate s tability and performance robustness guidelines for multivariable, flex ible aircraft flight control systems. A stability augmentation and str uctural mode control system, designed using the same classical techniq ue as on the original production aircraft, is evaluated to produce the new guidelines. Stability margins are computed for simultaneous gain and phase uncertainty in each of the control system feedback loops. Pe rformance weighting filters are chosen specifically from military flyi ng qualities specifications. The results of this research define exact ly how robust a control system of this type should be, such that any p erformance improvements achieved using more advanced design techniques can be compared directly.