Helicopter Individual Blade Control Through Optimal Output FeedBack

This paper presents an application of optimal output feedback control techniques to helicopter individual blade control (IBC). The controller architecture is based on a recent extension of optimal output feedback control theory to the design of fixed gain controllers for periodic systems. Constant feedback gains based on available rotor sensor measurements are calculated by minimizing a linear quadratic performance index using Floquet theory. The theory is applied to articulated rotor flap/lag stabilization, high speed hingeless rotor lag damping augmentation, and ground resonance suppression. It is shown that fixed gain output feedback can be used for stability augmentation of helicopter rotor systems. The implementation complexity associated with individual blade control is considerably reduced relative to previous formulations.