Shubiao S., Chengming P.

Song Shubiao, Pei Chengming Northwestern Polytechnical University, Xi¡¯an, 710072, P.R.China (bluer@mail.nwpu.edu.cn) According to the nonstationarity and processing requirements of flutter signal in progressional speed test, a method of recursive time-frequency analysis is proposed and variable parametric model based on basis function is adopted to realize the method. Adaptive algorithm is used to track a time-variant system, and parametric model with variable coefficients is obtained, and then calculation of varying parametric spectrum and flutter mode parameters is performed. The time-varying parameters is denoted by weighted sum of basis functions, then a linear time-variant problem is transformed to a time-invariant one, and recursive least square algorithm is used to compute the coefficients. By digital simulation and aero-elastic test with progressional speed in wind tunnel, it is proved that the method in this paper is able to meet the requirements of this kind of tests on processing precision and speed. Keywords: flutter test with progressional speed; nonstationary signal processing; time-variable parametric model