Parameter Identification of Flexible Aircraft Using Frequency Domain Output Error Approach

Abstract

Abstract Aerodynamic parameter estimation from flight data become a complex process when the aircraft has significant effects of flexibility on the flight dynamics, especially as the frequencies of the elastic modes become lower and approach those of the rigid body modes. In this paper, output error method (OEM) in frequency domain is applied to flight simulated data of a flexible aircraft to estimate the rigid body and aeroelastic derivatives. For the frequency domain estimation, flight data is generated using logarithmic frequency sweep input, and sensitivity of the estimated short period frequency and damping ratio to FFT window length is also investigated. Model validation is carried out by comparing time histories of the simulated and model predicted responses to multistep 3211 and sweep inputs.