CN-122015657-A - Vibration displacement measuring method and related device

CN122015657ACN 122015657 ACN122015657 ACN 122015657ACN-122015657-A

Abstract

The embodiment of the invention discloses a vibration displacement measurement method and a related device, belonging to the technical field of underwater vehicle testing, wherein the method comprises the following steps: substituting the stripe image light intensity distribution, background light intensity, stripe contrast, initial carrier phase and system displacement sensitivity coefficient of each pixel point on a reflection stripe image acquired by a camera positioned in the pressure-resistant shell of the underwater vehicle main body into a cosine function form formula of the stripe image light intensity distribution to obtain vibration displacement corresponding to each target point on the thin-wall skin to be detected. Therefore, five key parameters including background light intensity, stripe contrast, initial carrier phase and system displacement sensitivity coefficient of the pixel point are integrated instead of the single light intensity parameter, and are substituted into a cosine function form formula of stripe image light intensity distribution to perform vibration displacement calculation. Through the synergistic effect of the five parameters, the resolving precision of the vibration displacement of the thin-wall skin to be measured can be improved.

Inventors

SONG DONG
XU YANPENG
PAN GUANG
DU XIAOXU
SONG BAOWEI

Assignees

西北工业大学

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. A method of measuring vibration displacement, the method comprising: The method comprises the steps of acquiring a reflection fringe image acquired by a camera positioned in a pressure-resistant shell of an underwater vehicle main body, wherein the reflection fringe image is an image acquired by the camera aiming at a fringe pattern reflected by the thin-wall skin to be detected, which is subjected to mirror surface treatment, of the outside of the underwater vehicle, and the fringe image is projected by fringe projection equipment positioned in the pressure-resistant shell of the underwater vehicle main body; Acquiring stripe image light intensity distribution, background light intensity, stripe contrast, initial carrier phase and system displacement sensitivity coefficient of each pixel point on the reflection stripe image; Substituting the stripe image light intensity distribution, background light intensity, stripe contrast, initial carrier phase and system displacement sensitivity coefficient of each pixel point into a cosine function form formula of the stripe image light intensity distribution to obtain vibration displacement corresponding to each target point on the thin-wall skin to be detected, wherein the target point is a point corresponding to the pixel point on the thin-wall skin to be detected, and the cosine function form formula is that (X, y) represents camera pixel coordinates of the pixel, I (x, y) represents stripe image light intensity distribution of the pixel, A (x, y) represents background light intensity of the pixel, B (x, y) represents stripe contrast of the pixel, The initial carrier phase corresponding to the pixel point is represented, k represents the system displacement sensitivity coefficient, and h represents the vibration displacement.
2. The method of claim 1, wherein the obtaining a system displacement sensitivity coefficient comprises: Acquiring a fixed baseline distance between an optical center of the strip projection equipment and an optical center of the camera, a vertical distance between the strip projection equipment and a plane of the thin-wall skin to be detected, and a natural frequency of a strip pattern projected to the thin-wall skin to be detected by the strip projection equipment; Substituting the fixed baseline distance, the vertical distance and the natural frequency into a system displacement sensitivity coefficient calculation formula to obtain the system displacement sensitivity coefficient, wherein the system displacement sensitivity coefficient calculation formula is as follows , Which is indicative of the said natural frequency, Representing the fixed baseline distance, L represents the vertical distance.
3. The method of claim 1, wherein the initial carrier phase of the pixel is calculated as follows: ; where (x, y) denotes the camera pixel coordinates of the pixel point, Representing the initial carrier phase of the pixel point, And the natural frequency of the fringe pattern projected to the thin-wall skin to be detected by the fringe projection equipment is represented.
4. A vibration displacement measuring device for implementing the method according to any one of claims 1 to 3, comprising: The stripe projection equipment is used for projecting stripe patterns to the thin-wall skin to be detected which is subjected to mirror surface treatment outside the pressure-resistant shell of the underwater vehicle body under the condition that the stripe projection equipment is embedded inside the pressure-resistant shell of the underwater vehicle body; The camera is embedded in the pressure-resistant shell of the underwater vehicle body and is used for collecting reflection fringe images reflected by the thin-wall skin to be detected; A processor in communication with the camera for receiving the reflected fringe image transmitted by the camera and performing the steps of the method of any of claims 1-3.
5. The apparatus of claim 4, wherein the vibration displacement measuring means comprises: The device comprises a high-rigidity frame, a stripe projection device and a camera, wherein the high-rigidity frame is used for being fixed at a main bearing structure of the inner surface of a pressure-resistant shell of an underwater vehicle main body, the stripe projection device and the camera are respectively fixed at two sides of the high-rigidity frame through an adjustable transverse moving rod and a vertical telescopic rod and are used for forming an optical measurement main body with a thin-wall skin to be detected which is subjected to mirror surface treatment outside the underwater vehicle, the transverse moving rod and the vertical telescopic rod are used for adjusting the distance between the camera and the stripe projection device, the angle between the camera and the stripe projection device and the plane of the thin-wall skin to be detected and the distance between the camera and the stripe projection device and the plane of the thin-wall skin to be detected, and the optical center of the stripe projection device and the optical center of the camera form a fixed base line.
6. The apparatus of claim 4, wherein a camera in the vibration displacement measurement apparatus is connected to the underwater vehicle through an interface on the back of the camera, wherein a fringe projection device in the vibration displacement measurement apparatus is connected to the underwater vehicle through an interface on the back of the fringe projection device, and wherein the underwater vehicle is configured to power the camera and the fringe projection device.
7. The apparatus of claim 4, wherein the high rigidity frame comprises a plurality of vertical support columns, a plurality of bars and a plurality of rigid connection chassis, wherein the plurality of vertical support columns and the plurality of bars form a cuboid structure, the plurality of bars are connected with the top ends of the plurality of vertical support columns, the bottom ends of the plurality of vertical support columns are connected with the plurality of rigid connection chassis, and the rigid connection chassis is used for fixing the high rigidity frame inside the pressure housing of the underwater vehicle body.
8. The apparatus of claim 7, wherein the vibration displacement measuring apparatus further comprises two inclined mounting surfaces fixed to both side top ends of the high rigidity frame by adjustable lateral moving rods and vertical telescopic rods, respectively, the two inclined mounting surfaces being used for fixing the camera and the fringe projection device, respectively.
9. A computer readable storage medium storing a computer program which, when executed by a processor, causes the processor to perform the steps of the method of any one of claims 1 to 3.
10. A computer device comprising a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method of any of claims 1 to 3.

Description

Vibration displacement measuring method and related device Technical Field The invention relates to the technical field of underwater vehicle testing, in particular to a vibration displacement measuring method and a related device. Background The thin-wall skin of an underwater vehicle is used as an external key structure of the vehicle, and the vibration characteristics (especially the vibration displacement in the vertical direction) of the thin-wall skin directly influence the hydrodynamic performance, the structural stability and the navigation stealth of the vehicle. Because the underwater vehicle works in a complex environment with high pressure, darkness and water scattering for a long time, the thin-wall skin is thin in thickness and low in rigidity, and is easy to generate micro vibration due to the influence of water flow disturbance and vibration of the vehicle body, and strict requirements are put on high-precision measurement of vibration displacement of the underwater vehicle. Currently, a common method for measuring vibration of an underwater thin-wall structure mainly comprises contact type measurement (such as strain gauge and acceleration sensor adhesion measurement). The contact type measuring method needs to directly adhere the sensor to the surface of the skin to be measured, so that the mirror surface property and the structural integrity of the skin can be damaged, the vibration state of the skin is affected, the underwater sealing and pressure-resistant design difficulty of the sensor is high, the sensor is easily affected by underwater high pressure and corrosive environments, and the vibration displacement measuring precision is reduced. Therefore, the vibration displacement obtained by the vibration measurement of the underwater thin-wall structure by adopting a common method is low in effectiveness. Disclosure of Invention In view of the above, it is necessary to provide a vibration displacement measurement method and related device, which aims to solve the problem of low effectiveness of vibration displacement measurement. In a first aspect, an embodiment of the present application provides a vibration displacement measurement method, including: The method comprises the steps of acquiring a reflection fringe image acquired by a camera positioned in a pressure-resistant shell of an underwater vehicle main body, wherein the reflection fringe image is an image acquired by the camera aiming at a fringe pattern reflected by the thin-wall skin to be detected, which is subjected to mirror surface treatment, of the outside of the underwater vehicle, and the fringe image is projected by fringe projection equipment positioned in the pressure-resistant shell of the underwater vehicle main body; Acquiring stripe image light intensity distribution, background light intensity, stripe contrast, initial carrier phase and system displacement sensitivity coefficient of each pixel point on the reflection stripe image; Substituting the stripe image light intensity distribution, background light intensity, stripe contrast, initial carrier phase and system displacement sensitivity coefficient of each pixel point into a cosine function form formula of the stripe image light intensity distribution to obtain vibration displacement corresponding to each target point on the thin-wall skin to be detected, wherein the target point is a point corresponding to the pixel point on the thin-wall skin to be detected, and the cosine function form formula is that (X, y) represents camera pixel coordinates of the pixel, I (x, y) represents stripe image light intensity distribution of the pixel, A (x, y) represents background light intensity of the pixel, B (x, y) represents stripe contrast of the pixel,The initial carrier phase corresponding to the pixel point is represented, k represents the system displacement sensitivity coefficient, and h represents the vibration displacement. In some embodiments, the obtaining the system displacement sensitivity coefficient includes obtaining a fixed baseline distance between the optical center of the fringe projection device and the optical center of the camera, a vertical distance between the fringe projection device and the plane of the thin-wall skin to be measured, and a natural frequency of a fringe pattern projected by the fringe projection device to the thin-wall skin to be measured, substituting the fixed baseline distance, the vertical distance, and the natural frequency into a system displacement sensitivity coefficient calculation formula to obtain the system displacement sensitivity coefficient, wherein the system displacement sensitivity coefficient calculation formula is that,Which is indicative of the said natural frequency,Representing the fixed baseline distance, L represents the vertical distance. In some embodiments, the calculation formula of the initial carrier phase of the pixel is as follows: ; where (x, y) denotes the camera pixel coordinates of the pix