Construction and retrieval method of aircraft vibration fault database based on perceptual hash algorithm

Abstract

A construction and retrieval method of aircraft vibration fault database based on perceptual hash algorithm includes that a test data, a filtering, a resampling, a wavelet transform are read, and time-frequency domain data matrix is transformed into gray-scale image, the gray-scale image is mapped to a new fixed-size gray-scale image by hashing algorithm, the mapped gray-scale image is mapped twice and converted into binary image, the elements in the binary image matrix are rearranged to generate a hash value; the generated hash value is compared to the hash value in the database one by one, coherence coefficient is calculated: and then the fault analysis and prejudgment are carried out. The invention summarizes the vibration fault data and experience of civil aircraft, constructs the vibration fault database of civil aircraft, directly processes the collected complete vibration data in time domain, and compares the data with the data in the database, so that the fault type can be quickly located, the engineering use precision can be satisfied, the engineering is safe and reliable, and is suitable for popularization and popularization.

Description

technical field [0001] The invention relates to the technical field of fault diagnosis of civil aircraft vibration data, in particular to an aircraft vibration fault database construction and retrieval method based on perceptual hash algorithm. Background technique [0002] Vibration is a common phenomenon in nature and engineering. Unreasonable vibration often affects the functions of instruments and equipment, reduces the working accuracy of mechanical equipment, aggravates component wear, and even causes structural fatigue damage. With the development of modern science and technology, aircraft design Modern engineering designs such as ship design, civil engineering design, and mechanical design are becoming more and more sophisticated, and higher and stricter requirements are put forward for the solution to vibration problems; especially in the design of aircraft, the solution to vibration problems is particularly important; And during the whole flight process, vibration ...

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Problems solved by technology

[0006] ① The doctoral dissertation of Yuan Chunhui of Huazhong University of Science and Technology - "Research on the Testing Method of Vibration Source Characteristics of Mechanical Equipment". In general, a ring-shaped piezoelectric force sensor is connected in series between the equipment foot and the foundation. Under elastic installation conditions, a ring-shaped piezoelectric force sensor is generally connected in series between the equipment foot and the vibration isolator; in fact, In this installation state, the force transmitted from the equipment foot to the vibration isolator or the foundation is transmitted by two paths, one is that the equipment foot is transmitted to the vibration isolator or foundation through the force sensor, and the other is transmitted by the equipment foot Transmitted to the mounting bolts and then to the vibration isolator or foundation, the sensor can only measure the force transmitted through it, but cannot measure the force transmitted through the bolts. It is generally believed that the force transmitted through the bolts can reach 10% to 30% of the resultant force. The sensor can only measure 70% to 90%, and the measurement error is relatively large, which does not meet the use requirements of existing high-precision flying devices;

[0007] ②Wang Shuchu's "Using Ultrasonic Measuring Dynamic Force" published in "Applied Acoustics" in February 1990. The method used in this document is the ultrasonic measurement method. The data processing is very complicated and requires a complicated ultrasonic generating device, which is not suitable for popularization. universal;

[0008] ③Song Kongjie's "Discussion on the Measurement of Dynamic Force" published in the "Journal of Shandong University of Technology" in the first issue of 1984. This document also mentioned the measurement method using piezoelectric force sensors and strain force sensors. The sensor is also a single-sensor measurement method in the measurement. The strain-type force sensor has a small measurement frequency band and can only measure low frequencies, and it is easy to change the impedance characteristics of the system vibration isolation. In engineering, there are also requirements for the measurement of dynamic forces in high-frequency bands, and It is not expected to change the impedance characteristics of the vibration isolation system, which is far from adapting to the use standards of modern spacecraft

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