CN-122009523-A - Special method for measuring waviness of RVSM key region of airplane

CN122009523ACN 122009523 ACN122009523 ACN 122009523ACN-122009523-A

Abstract

The application belongs to the technical field of aircraft design, and particularly relates to a special method for measuring waviness of an RVSM key region of an aircraft, which comprises the steps of manufacturing target points of a measuring region, and pasting the target points on the measuring region; the method comprises the steps of locating target points, collecting surface information of a measuring area, processing the surface information to obtain measuring data, conducting theoretical data boundary matching on the measuring data to obtain measuring point cloud data, conducting standard surface fitting on the measuring point cloud data to obtain a smooth curved surface, conducting fitting on the smooth curved surface and an actually measured curved surface, conducting waviness parameter analysis, and obtaining wavelength, amplitude and waviness parameters of each wave on an actually measured intersecting line. The measurement system is used for quick calibration, target point measurement and surface measurement and detection of a measurement area, and further measurement data and theoretical data boundary matching, reference surface fitting and actual measurement surface fitting are started, and finally waviness analysis is carried out, so that the measurement accuracy is greatly improved, and the measurement period is shortened.

Inventors

LONG WENGANG
DANG YUHUI
ZHANG YANJUN
QIAO CHAOJUN
MA YUMIN
JIANG SHIHAO
ZHAO ZUOKAI

Assignees

中国航空工业集团公司西安飞机设计研究所

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The special method for measuring the waviness of the RVSM key region of the aircraft is characterized by comprising the following steps of: manufacturing target points of a measuring area, and pasting the target points on the measuring area; acquiring surface information of a measurement area through target point positioning, and processing to obtain measurement data; Carrying out theoretical data boundary matching on the measured data to obtain measured point cloud data, and carrying out reference surface fitting on the measured point cloud data to obtain a smooth surface; fitting the smooth curved surface and the actually measured curved surface, and then carrying out waviness parameter analysis to obtain the wavelength, amplitude and waviness parameters of each wave on the actually measured intersecting line.
2. The method for measuring the waviness of the RVSM key region of the airplane according to claim 1, wherein the surface information of the measuring region is collected, and the method is as follows: Setting the density, scanning parameters and scanning mode of the measuring points, and collecting the surface information of the measuring area by adopting a laser scanner; the laser scanner transmits the collected data to the background equipment, the background equipment performs integrity and relative position relation inspection on the collected data, and after the inspection is passed, measurement data are obtained.
3. The method for measuring the waviness of the key areas of the RVSM of the airplane according to claim 2, wherein the density of the measuring points is set to be 5mm, the scanning parameters comprise scanning resolution, exposure parameters and scanning control parameters, and the scanning mode adopts a long-distance scanning mode.
4. The method for measuring the waviness of the key area of the RVSM of the airplane according to claim 1, wherein the coordinate conversion function is used for carrying out theoretical data boundary matching on the measured data according to the coordinate of the matching point in the measured data and the corresponding coordinate point on the theoretical data, so as to obtain the measured point cloud data.
5. The method for measuring the waviness of the key area of the RVSM of the airplane according to claim 1, wherein the measured point cloud data is subjected to reference surface fitting, and the reference surface is used for processing the measured point cloud data by a least square method according to the measured surface characteristics to form a smooth surface.
6. The method for measuring the waviness of the key areas of the RVSM of the airplane according to claim 5, wherein the least square method is as follows: f(x)=c0+c1x+c2x2+...+cnxn; wherein c0, c1, c2, cn, xn are set curve shape coefficients, x is set axial dimensionless parameter, and f (x) is reference curve longitudinal coordinate.
7. The method for measuring the waviness of the key area of the RVSM of the airplane according to claim 1, wherein when the waviness parameter analysis is carried out, a given plane is intersected with a reference curved surface and an actual measurement curved surface through plane intersection line analysis, curve fluctuation data on the plane are obtained, and the wavelength, the amplitude and the waviness parameter of each wave on the actual measurement intersection line are obtained through calculation.
8. The method for measuring the waviness of the RVSM critical region of the airplane according to claim 7, wherein the specific method for analyzing the intersecting line of the plane is as follows: Intersecting the given plane with the reference curved surface and the actually measured curved surface to obtain a reference curve and an actually measured curve in the given plane, calculating the difference value of the actually measured curve and the reference curve in the normal direction of the reference curve in the given plane to obtain a waviness curve, and calculating to obtain the position of the point with the maximum or minimum curvature on the waviness curve so as to obtain the wave crest and the wave trough of the wave; The length of the straight line connecting adjacent wave crests and wave troughs is the wavelength of the wave, and the distance between the wave trough point between the adjacent wave crests and the wave crest connecting line is the amplitude.
9. The method for measuring waviness of an RVSM key region of an aircraft according to claim 7, wherein when the smooth curved surface is fitted with the actually measured curved surface, the maximum deviation of fitting of the actually measured curved surface and the point cloud of the smooth curved surface is not more than 0.1mm, and the fitting is completed.
10. The method for measuring the waviness of the key area of the RVSM of the airplane according to claim 7, wherein waviness analysis is carried out by adopting waviness analysis software, during analysis, fitted data point clouds are screened according to a distance of 2mm, a measuring area reference curved surface is formed by fitting the screened data point clouds, 48 horizontal sections are taken on each side curved surface of the measuring area reference curved surface, the distance between the horizontal sections is 20mm, and the horizontal sections near the center of the sensor pass through the center point of the sensor.

Description

Special method for measuring waviness of RVSM key region of airplane Technical Field The application belongs to the technical field of aircraft design, and particularly relates to a special method for measuring waviness of an RVSM key region of an aircraft. Background The aircraft is operated in RVSM airspace and its altitude measurement system error is required to meet the requirements specified in advisory notice AC-21-13 (aircraft airworthiness approval for implementing 300 meters (1000 feet) vertical interval standard operation in RVSM airspace). The static pressure measured by the aircraft static pressure source is related to the flying height, and a key area is defined near the aircraft static pressure source in RVSM airworthiness, wherein factors such as the skin surface waviness, the static pressure sensor installation step difference and the like in the key area are important sources of errors of the height measurement system. The surface waviness of the aircraft is measured by a two-dimensional measurement method and a three-dimensional measurement method, and a three-dimensional photogrammetry method is generally adopted for an RVSM key area of the aircraft, and has the advantages of high precision and high speed. But for the multi-stage RVSM critical area, higher demands are placed on the accuracy, stability and efficiency of the waviness measurement data. The conventional three-dimensional measurement method cannot meet the requirement of RVSM surface waviness measurement. Thus, how to make more efficient RVSM surface waviness measurements is a problem to be solved. Disclosure of Invention In order to solve the problems, the application provides a special method for measuring the waviness of an RVSM key region of an airplane, which aims to solve the problem that the traditional three-dimensional measurement method in the prior art cannot meet the requirement for measuring the waviness of the RVSM surface. The technical scheme of the application is that the special method for measuring the waviness of the RVSM key region of the airplane comprises the following steps: manufacturing target points of a measuring area, and pasting the target points on the measuring area; acquiring surface information of a measurement area through target point positioning, and processing to obtain measurement data; Carrying out theoretical data boundary matching on the measured data to obtain measured point cloud data, and carrying out reference surface fitting on the measured point cloud data to obtain a smooth surface; fitting the smooth curved surface and the actually measured curved surface, and then carrying out waviness parameter analysis to obtain the wavelength, amplitude and waviness parameters of each wave on the actually measured intersecting line. Preferably, the surface information of the measurement area is collected as follows: Setting the density, scanning parameters and scanning mode of the measuring points, and collecting the surface information of the measuring area by adopting a laser scanner; the laser scanner transmits the collected data to the background equipment, the background equipment performs integrity and relative position relation inspection on the collected data, and after the inspection is passed, measurement data are obtained. Preferably, the density of the measuring points is set to be 5mm, the scanning parameters comprise scanning resolution, exposure parameters and scanning control parameters, and the scanning mode adopts a long-distance scanning mode. Preferably, according to the coordinate of the matching point in the measurement data and the corresponding coordinate point on the theoretical data, the theoretical data boundary matching is performed on the measurement data through a coordinate conversion function, so as to obtain the measurement point cloud data. Preferably, the measurement point cloud data is subjected to reference surface fitting, and the reference surface is used for processing the measurement point cloud data by a least square method according to the measurement surface characteristics to form a smooth surface. Preferably, the least square method is: f(x)=c0+c1x+c2x2+...+cnxn; wherein c0, c1, c2, cn, xn are set curve shape coefficients, x is set axial dimensionless parameter, and f (x) is reference curve longitudinal coordinate. Preferably, when the waviness parameter analysis is performed, intersecting a given plane with a reference curved surface and an actually measured curved surface through plane intersection line analysis, obtaining curve fluctuation data on the plane, and calculating to obtain the wavelength, amplitude and waviness parameter of each wave on the actually measured intersection line. Preferably, the specific method for analyzing the intersecting line of the plane is as follows: Intersecting the given plane with the reference curved surface and the actually measured curved surface to obtain a reference curve and an actually measured curve