CN-122016244-A - Dynamic performance detection method for hollow anti-resonance optical fiber

CN122016244ACN 122016244 ACN122016244 ACN 122016244ACN-122016244-A

Abstract

The invention relates to the technical field of material damage detection, in particular to a dynamic performance detection method of an air core anti-resonance optical fiber, which is characterized in that in the process of driving the optical fiber to move by a robot, an optical cable curvature vector and an impact conduction vector which represent stress states of different positions of the optical fiber along the body are constructed by collecting relative distances and instantaneous accelerations of a base in real time, and the local thermal damage vector and the structural damage vector of the optical fiber along the body are iteratively inverted by using a recursive parameter estimation algorithm in combination with relative thermal characteristic values and relative structural characteristic values which are decoupled and extracted from periodic pulse data.

Inventors

HE JUN
YU YUHANG
SHAO BO

Assignees

浙江富春江光电科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260416

Claims (10)

1. A method for detecting dynamic performance of a hollow anti-resonant fiber, the method comprising: Acquiring all periodic pulse data corresponding to each sampling moment and the relative distance and instantaneous acceleration of a base corresponding to the robot in the process that the robot drives the optical fiber to perform space movement, wherein an optical cable is positioned between a flange at the tail end of the robot and the base; determining an optical cable curvature vector at each sampling moment according to the relative distance of the base relative to the total length of the optical cable; Determining corresponding relative thermal characteristic values based on the reference relative magnitudes of the pulse main peak trailing edge energy of all the periodic pulse data at each sampling time; Based on the acquisition principle of the optical cable thermal injury vector, carrying out iterative updating according to the regression relation between the relative structural feature value and the impact conduction vector, and determining the optical cable structural injury vector at each sampling moment; and detecting the dynamic performance of the hollow anti-resonance optical fiber according to the optical cable thermal damage vector and the optical cable structure damage vector.
2. The method for detecting dynamic performance of a hollow anti-resonant fiber according to claim 1, wherein the process of obtaining the cable curvature vector comprises: determining the central sag of the optical cable at each sampling moment according to the relative deviation condition between the total length of the optical cable and the relative distance of the base at each sampling moment; Performing parabolic fitting according to the position of each local optical cable section in the optical cable, and determining corresponding morphological distribution characteristic values; And determining the equivalent bending curvature of each local optical cable segment at each sampling time according to the product of the morphological distribution characteristic value and the sagging of the optical cable center, and sequentially arranging the equivalent bending curvatures of all the local optical cable segments to determine the optical cable curvature vector.
3. The method for detecting dynamic performance of hollow anti-resonance optical fiber according to claim 2, wherein the obtaining process of the central sag of the optical cable comprises: And performing positive correlation mapping on the difference between the square of the total length of the optical cable and the square of the relative distance of the base, and determining the central sag of the optical cable at each sampling moment.
4. The method for detecting dynamic performance of a hollow anti-resonance optical fiber according to claim 2, wherein the process of obtaining the morphological distribution characteristic value comprises: Arranging all local optical cable segments along the direction from the end flange of the robot to the base, determining a local optical cable segment sequence, normalizing the index value corresponding to each local optical cable segment in the local optical cable segment sequence, determining a corresponding index coefficient, performing positive correlation mapping on the product of the negative correlation mapping value of the index coefficient of each local optical cable segment and the corresponding index coefficient, and determining the morphological distribution characteristic value of each local optical cable segment.
5. The method for detecting the dynamic performance of a hollow anti-resonant fiber according to claim 4, wherein the process of obtaining the impact conduction vector comprises: Performing differential operation on the acceleration of each sampling moment and the acceleration of the previous sampling moment to determine the instantaneous impact scalar of each sampling moment, performing exponential negative correlation mapping on the product between the index coefficient of each local optical cable section and the total length of the optical cable, and determining the corresponding exponential decay coefficient; Determining the effective impact strength of each local optical cable segment at each sampling time according to the product between the exponential decay coefficient and the instantaneous impact scalar; the effective impact strength of all the local optical cable segments is arranged along the direction from the end flange of the robot to the base, and the impact conduction vector of each sampling moment is determined.
6. The method for detecting dynamic performance of a hollow-core antiresonant optical fiber according to claim 1, wherein the process of obtaining the relative thermal characteristic value comprises: The method comprises the steps of obtaining a main pulse starting moment, a main pulse ending moment and a trailing edge integral ending moment of each period pulse data, integrating waveform amplitude values of each period pulse data in a section corresponding to the main pulse starting moment to the main pulse ending moment to be used as main peak energy, integrating waveform amplitude values of each period pulse data in a section corresponding to the main pulse ending moment to the trailing edge integral ending moment to be used as trailing edge energy, determining a trailing edge energy duty ratio of each period pulse data according to a ratio between the main peak energy and the trailing edge energy, determining corresponding absolute thermal characteristic values according to an average value of the trailing edge energy duty ratios of all sampling moments corresponding to each sampling moment, and determining relative thermal characteristic values of each sampling moment according to a difference value between the absolute thermal characteristic values and preset base line thermal characteristic values.
7. The method for detecting dynamic performance of a hollow anti-resonant fiber according to claim 1, wherein the process of obtaining the relative structural feature value comprises: And determining the relative structural characteristic value of each sampling moment according to the difference value between the absolute structural characteristic value and the preset baseline structural characteristic value.
8. The method for detecting dynamic performance of a hollow anti-resonant fiber according to claim 1, wherein the process for obtaining the thermal damage vector of the optical cable comprises: After splicing a constant 1 at the tail of the optical cable curvature vector, transposition is carried out, and an amplified excitation vector at each sampling moment is determined; Determining a predicted thermal characteristic value according to the product between the transpose of the amplified excitation vector at each sampling time and the optical cable thermal damage vector at the previous sampling time; calculating a Kalman gain vector of each sampling moment according to the iteration covariance matrix of the previous sampling moment of each sampling moment and the augmented excitation vector; And calculating the sum vector of the damage parameter vector correction quantity at each sampling moment and the corresponding optical cable thermal damage vector at the previous sampling moment, and determining the optical cable thermal damage vector at each sampling moment.
9. The method for detecting the dynamic performance of a hollow-core antiresonant optical fiber according to claim 8, wherein the determining the thermal damage vector of the optical cable at each sampling time further comprises: And sequentially multiplying the Kalman gain vector, the transpose vector of the augmented excitation vector and the covariance matrix of the previous sampling moment by a matrix at each sampling moment to determine a covariance correction matrix, and weighting the matrix obtained by subtracting the covariance matrix of the previous sampling moment from the iteration covariance matrix of the covariance correction matrix by a preset forgetting factor to determine an iteration covariance matrix of each sampling moment.
10. The method for detecting the dynamic performance of the hollow anti-resonance optical fiber according to claim 4, wherein the process for detecting the dynamic performance of the hollow anti-resonance optical fiber according to the optical cable thermal damage vector and the optical cable structural damage vector comprises the following steps: the last element in the optical cable thermal damage vector is removed, and an effective thermal damage vector is determined, wherein in the effective thermal damage vector, an index value corresponding to an element larger than a preset thermal damage threshold value is used as a thermal damage index value; Removing the last element in the optical cable structural damage vector to determine an effective structural damage vector, wherein in the effective structural damage vector, an index value corresponding to an element larger than a preset structural damage threshold is used as a structural damage index value; and detecting the dynamic performance of the hollow anti-resonance optical fiber according to the thermally damaged optical cable section and the structurally damaged optical cable section.

Description

Dynamic performance detection method for hollow anti-resonance optical fiber Technical Field The invention relates to the technical field of material damage detection, in particular to a dynamic performance detection method of a hollow anti-resonance optical fiber. Background Hollow-Core antiresonant fibers (HC-ARFs) exhibit excellent high damage threshold and low nonlinear effects due to their extremely low light and material overlap factors, and are increasingly replacing solid-Core fibers as the transmission medium of choice in the field of high-end ultrafast laser precision machining. In a typical industrial application scenario, an optical fiber is typically mounted at the end of a six-axis industrial robot, with a random robot flange performing high-speed, multi-dimensional spatial movements to effect cutting or welding of complex curved parts. However, the long-term dynamic movement is very easy to cause the optical fiber to be aged or damaged, so that the processing accident is caused, and therefore, the real-time state monitoring of the optical fiber is very important. In the prior art, an on-line monitoring mode is generally adopted to integrate a photodiode at an optical fiber output end, and the total optical power transmitted by an optical fiber is collected in real time, so that a shutdown alarm is triggered once the power is monitored to be greatly attenuated. However, the endpoint monitoring method can only acquire the accumulated total value of the transmission loss of the whole optical fiber, can not acquire the local damage distribution information of the optical fiber along the body, namely can not locate a specific damaged position, can not distinguish the physical mechanism of damage, namely can not distinguish whether the material is thermally aged or is structurally micro-cracked, namely, the method for detecting the dynamic performance of the optical fiber by using the endpoint photodiode in the prior art can not realize accurate local damage location and mechanism distinction, so that the accuracy of detecting the dynamic performance of the hollow anti-resonance optical fiber is lower. Disclosure of Invention In order to solve the technical problem of lower accuracy of optical fiber dynamic performance detection by an endpoint photodiode in the prior art, the invention aims to provide a method for detecting the dynamic performance of a hollow anti-resonance optical fiber, which adopts the following technical scheme: the first aspect of the present invention provides a method for detecting dynamic performance of a hollow anti-resonant fiber, comprising: Acquiring all periodic pulse data corresponding to each sampling moment and the relative distance and instantaneous acceleration of a base corresponding to the robot in the process that the robot drives the optical fiber to perform space movement, wherein an optical cable is positioned between a flange at the tail end of the robot and the base; determining an optical cable curvature vector at each sampling moment according to the relative distance of the base relative to the total length of the optical cable; Determining corresponding relative thermal characteristic values based on the reference relative magnitudes of the pulse main peak trailing edge energy of all the periodic pulse data at each sampling time; Based on the acquisition principle of the optical cable thermal injury vector, carrying out iterative updating according to the regression relation between the relative structural feature value and the impact conduction vector, and determining the optical cable structural injury vector at each sampling moment; and detecting the dynamic performance of the hollow anti-resonance optical fiber according to the optical cable thermal damage vector and the optical cable structure damage vector. Further, the obtaining process of the curvature vector of the optical cable comprises the following steps: determining the central sag of the optical cable at each sampling moment according to the relative deviation condition between the total length of the optical cable and the relative distance of the base at each sampling moment; Performing parabolic fitting according to the position of each local optical cable section in the optical cable, and determining corresponding morphological distribution characteristic values; And determining the equivalent bending curvature of each local optical cable segment at each sampling time according to the product of the morphological distribution characteristic value and the sagging of the optical cable center, and sequentially arranging the equivalent bending curvatures of all the local optical cable segments to determine the optical cable curvature vector. Further, the obtaining process of the central sag of the optical cable comprises the following steps: And performing positive correlation mapping on the difference between the square of the total length of the optical cable and the square of the relat