Aircraft elastic vibration online identification algorithm based on modulation sliding Fourier transform

Abstract

The invention discloses an aircraft elastic vibration online identification algorithm based on modulation sliding Fourier transform, and belongs to the technical field of flight control. The algorithmprovided by the invention comprises the following steps: 1, periodically sampling an attitude angular velocity through a rate gyroscope, and updating a time domain array; 2, calling data in the timedomain array to carry out modulation sliding Fourier transform, and carrying out frequency domain windowing processing; and 3, performing descending sort on the frequency domain analysis result according to the amplitude to identify the elastic vibration frequency and amplitude of the aircraft. According to the aircraft elastic vibration online identification algorithm based on modulation slidingFourier transform provided by the invention, the aircraft elastic vibration frequency and amplitude are identified on line, and a foundation is laid for the adaptive design of an on-missile filter soas to improve the flight control of the aircraft.

Description

Technical field [0001] The invention relates to the field of aircraft flight control, and particularly relates to an online identification method for aircraft elastic vibration. Background technique [0002] During the flight of the aircraft, the elastic vibration is easily excited by the projectile under the action of aerodynamic force and external force. The coupling of elastic vibration and rigid body control system will affect the stability margin of the system on the one hand, and affect the performance of steering gear on the other hand, and seriously affect the flight control. Quality. Aiming at the problem of elastic vibration, in engineering, the elastic mode is generally measured through ground tests. The filter is conservatively designed by increasing the depth and width, which affects the quality of flight control. Moreover, the new generation of aircraft has a wide flying airspace, long time, fast speed, etc. Characteristics, the harsh flight environment and complex ...

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Problems solved by technology

[0002] During the flight of the aircraft, the elastic vibration is easily excited by the projectile body under the action of aerodynamic force and external force. The coupling between the elastic vibration and the rigid body control system will affect the stability margin of the system on the one hand, and affect the performance of the steering gear on the other hand, seriously affecting the flight control. Quality, for the problem of elastic vibration, in engineering, the elastic mode is generally measured through ground tests. The filter is conservatively designed by increasing the depth and width, which affects the flight control quality, and the new generation of aircraft has a wide flight space, long time, and fast speed. The harsh flight environment and complex and changeable flight conditions make the elastic mode have strong time-varying and strong uncertainty characteristics. It is difficult to simulate accurate elastic vibration modal information through ground modal tests. Therefore, the elastic vibration online It is particularly important to identify

[0003] In order to carry out online identification of aircraft elastic vibration, existing methods include references: [1] Zhang Wanle, Wang Xiaohu. Aircraft Elastic Adaptive Filtering Method Based on Wavelet Transform and Singular Value Decomposition [J]. Aerospace Control, 2018, 36( 4): 59-64; [2] Chu Longfei, Wu Zhigang. Design and Simulation of Missile Adaptive Structural Filter [J]. Acta Aeronautics Sinica, 2011, 32(2): 195-201; [3] Kang Yiru, Shen Hanlin .Fast mechanical resonance suppression based on SDFT and adaptive three-parameter notch filter[J]. Micromotor, 2018,51(5):25-30; based on wavelet transform and singular value decomposition described in literature [1] The frequency of the elastic mode shape is estimated online, but only the elastic mode shape corresponding to the largest singular value can be identified. In literature [2], the recursive least squares method is used to identify the modal parameters of the missile online, but this algorithm relies on the projectile model and is reliable. The accuracy is difficult to guarantee. In the literature [3], the sliding Fourier transform (Sliding Discrete Fourier Transform, SDFT) is used to detect the resonant frequency online, but the stability of the algorithm and the accuracy of frequency identification are poor under long-term work.

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