Oscillation mode flight data analysis based on FFT

Fu, Jingcheng; Huang, Jun; Wang, Libo; Song, Lei

doi:10.1108/aeat-04-2018-0139

Cited by 3 publications

(4 citation statements)

References 8 publications

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“…The natural frequency and the damping ratio are used to describe the Dutch roll mode. According to the sideslip angle data, the natural frequency and the damping ratio were identified using the fast fourier transform (FFT)-based half-power bandwidth method (Fu et al , 2019). This method has been compared with the time-domain peak attenuation method in Fu’s research (Fu et al , 2019).…”

Section: Resultsmentioning

confidence: 99%

“…According to the sideslip angle data, the natural frequency and the damping ratio were identified using the fast fourier transform (FFT)-based half-power bandwidth method (Fu et al , 2019). This method has been compared with the time-domain peak attenuation method in Fu’s research (Fu et al , 2019). The comparison results indicated the advantages of the FFT-based half-power bandwidth method when the aircraft oscillation mode identification is needed.…”

Section: Resultsmentioning

confidence: 99%

“…In this case, the artificial addition of data will have a great impact on the identified results. In Fu’s research (Fu et al , 2019), the influence of sampling time to results has been analysed. The results show that increasing sampling time help to make the results more accurate.…”

Section: Resultsmentioning

confidence: 99%

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Flight testing verification of lateral-directional dynamic stability of gliding birds due to wing dihedral

Wei

Liu²,

Huang

et al. 2022

AEAT

Self Cite

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Purpose Unlike conventional aircraft, birds can glide without a vertical tail. The purpose of this paper is to analyse the influence of dihedral angle spanwise distribution on lateral-directional dynamic stability by the simulation, calculation in the development of the bird-inspired aircraft and the flight testing. Design/methodology/approach The gliding magnificent frigatebird (Fregata magnificens) was selected as the study object. The geometric and mass model of the study object were developed. Stability derivatives and moments of inertia were obtained. The lateral-directional stability was assessed under different spanwise distributions of dihedral angle. A bird-inspired aircraft was developed, and a flight test was carried out to verify the analysed results. Findings The results show that spanwise distribution changing of dihedral angle has influence on the lateral-directional mode stability. All of the analysed configurations have convergent Dutch roll mode and rolling mode. The key role of dihedral angle changing is to achieve a convergent spiral mode. Flight test results show that the bird-inspired aircraft has a well-convergent Dutch roll mode. Practical implications The theory that birds can achieve its lateral-directional stability by changing its dihedral angle spanwise distribution may explain the stability mechanism of gliding birds. Originality/value This paper helps to improve the understanding of bird gliding stability mechanism and provides bio-inspired solutions in aircraft designing.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Flight testing verification of lateral-directional dynamic stability of gliding birds due to wing dihedral

Wei

Liu²,

Huang

et al. 2022

AEAT

Self Cite

View full text Add to dashboard Cite

show abstract

“…Various methods regarding CFD, flight tests, wind tunnel experiments, etc. are employed to study the conversion characteristics [8][9][10]. The conversion corridor is an effective method to evaluate the conversion flight performance.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Flight Envelope for V/STOL Aircraft with Multiple Flight Modes

Wang

et al. 2022

Aerospace

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Vertical or short take-off and landing (V/STOL) aircraft generally have three flight modes, namely, vertical take-off and landing (VTOL), conversion, and cruise, according to the variable angle of propulsion direction to the fuselage axis. However, the traditional flight envelope or conversion corridor lacks the capability to comprehensively present the flight characteristics of these three modes. Pursuant to this, the purpose of this paper was to present a three-dimensional (3D) flight envelope that combines propulsion direction, airspeed, and altitude in one figure. The 3D envelope was constructed subject to the constraints of power rating and equilibrium conditions. To verify its effectiveness, the flight data of XV-15 was used to generate the 3D envelope, following the projection along with the cross-section, which was compared with the traditional flight envelope and conversion corridor, respectively. The maximum specific excess power (SEP) of each flight state was also promptly obtained. In the case study, the flight performance of a rotor-wing aircraft was comprehensively analyzed using the generated 3D envelope. The proposed method in this study exhibited its versatility and capability to demonstrate the performance in all flight modes intuitively, which promoted the efficiency of V/STOL aircraft flight performance analysis as well.

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Fault Diagnosis Method of Gearbox Based on Sound Pressure Signal Analysis

Guo

Wang

et al. 2021

J. Phys.: Conf. Ser.

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The gearbox structure is complex, so it is difficult to determine the root cause of the problem after abnormal sound appears. The method of sound pressure signal analysis is used to analyze the abnormal sound of gearbox. The spectrum analysis method is used as the data processing method. The sound pressure of a kind of abnormal sound of gearbox is collected. By analyzing its frequency characteristics and structural characteristics, it is judged that the gear is abnormal. The accuracy of the inference based on the result of sound pressure analysis is verified by the shape and position detection of the gear. The results show that through the frequency analysis of the sound pressure signal, the root cause of the gearbox problem can be accurately determined.

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Oscillation mode flight data analysis based on FFT

Cited by 3 publications

References 8 publications

Flight testing verification of lateral-directional dynamic stability of gliding birds due to wing dihedral

Flight testing verification of lateral-directional dynamic stability of gliding birds due to wing dihedral

Three-Dimensional Flight Envelope for V/STOL Aircraft with Multiple Flight Modes

Fault Diagnosis Method of Gearbox Based on Sound Pressure Signal Analysis

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