Real-Time Estimation of Bare-Airframe Frequency Responses from Closed-Loop Data and Multisine Inputs

摘要

A method is presented for estimating frequency responses of multiple-input multiple-output bare-airframedynamics from flight test data containing feedback control and/or mixing of control effectors. Orthogonal phaseoptimizedmultisines are used to simultaneously excite each input with unique harmonic frequencies, at whichfrequency responses are computed as ratios of output-to-input Fourier transform data. The confounding effects offeedback and mixing are resolved by interpolation of the frequency responses. The analysis can be run in batch forpostflight analysis, or in real time as the aircraft is flying. The effectiveness of the method was verified usingsimulations of the subscale T-2 generic transport airplane with rate feedback. The method was also demonstratedusing flight test data from the X-56A MUTT aeroelastic airplane, which was flown with both feedback control andmixing.