A Frequency Analysis of the Control Input for Right Test

Kwon, Tae-Hee; Chang, Jae-Won; Choi, Sun-Woo; Seong, Kie-Jeong

Journal of the Korea Institute of Military Science and Technology 2005;8(1):39-48.

Tae-Hee Kwon, Jae-Won Chang, Sun-Woo Choi, Kie-Jeong Seong

KARI

비행시험용 조종입력의 주파수분석

권태희, 장재원, 최선우, 성기정

한국항공우주연구원 항공세부계통그룹

Abstract

After the development of the Firefly, flight tests have been performed to verify the performance and get the parameters for the mathematical model of the aircraft. The flight test data is used to get parameters for the mathematical model of the aircraft through the parameter identification process. An arbitrary control input is applied to the test flight which is a part of parameter identification process. A square wave has been used a control input which is called Doublet signal. The aspect of the signal is same length and magnitude in both (+) and (-) directions such as sine wave. The Doublet signal is composed of a dominant frequency and many high frequencies, so that it is appropriate signal to excite the motion of an aircraft. In this paper, the control input of the flight test data has been analyzed to check the efficiency of the control input using DFT(Discrete Fourier Transform). From the result of analysis, an alternative input was extracted.