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CN-122016643-A - Method and device for rapidly characterizing and testing photochromic performance of knitted fabric

CN122016643ACN 122016643 ACN122016643 ACN 122016643ACN-122016643-A

Abstract

The invention provides a method and a device for rapidly characterizing and testing photochromic performance of a knitted fabric, which realize rapid, quantitative and repeatable characterization of the photochromic performance of the knitted fabric and output key indexes such as steady-state color difference, color change/fading rate, fatigue coefficient and the like by means of ultraviolet LED array closed-loop light intensity control, tension coupling clamping, multi-angle composite photoelectric sensing array, dynamic modulation illumination and phase locking detection, texture compensation and soft measurement prediction models, and solve the problems of long testing time, no consideration of knitting structure characteristics and lack of tension coupling in the prior art.

Inventors

  • YU JIAHAI
  • ZHANG XUELI

Assignees

  • 广东睿程智造科技有限公司

Dates

Publication Date
20260512
Application Date
20251217

Claims (10)

  1. 1. The method for rapidly characterizing and testing the photochromic performance of the knitted fabric is characterized by comprising the following steps of: sample preparation and tension setting, namely mounting the knitted fabric sample on a tension control clamping mechanism, enabling the knitted fabric to reach preset elongation in the transverse direction and the longitudinal direction through motor driving, and realizing stable maintenance of set tension through feedback closed loop control of a tension sensor; A light source plane light intensity closed-loop calibration step, namely starting an ultraviolet LED array to light with initial driving current, reading an output signal of a reference ultraviolet light intensity sensor, converting the output signal by an ADC, and executing a closed-loop control algorithm by a processor to adjust the LED driving current so as to enable the measured light intensity to converge to the target light intensity and maintain the stability; A step of dynamically modulating illumination and synchronously sampling, namely switching the ultraviolet LED array into a dynamic modulation mode in a square wave or step mode, and simultaneously starting a multi-channel photoelectric sensing array to synchronously acquire the output of each channel at a sampling frequency; A phase-locked detection and multi-dimensional feature extraction step, namely calculating the average value of each channel signal, obtaining in-phase and quadrature components through multiplication and integration of the average value and a modulation reference signal, realizing digital phase-locked detection, and extracting multi-dimensional features related to photochromic dynamic response; A step of calculating a photochromic performance soft measurement model, in which the extracted multidimensional feature vector is input into a pre-trained machine learning model after being subjected to Z-score standardization pretreatment, and the estimated values of steady-state color-changing chromatic aberration, a color-changing rate constant and a fatigue coefficient are output; and a rapid evaluation index calculation step, namely calculating photochromic rapid evaluation indexes of the knitted fabric based on the estimated performance indexes and carrying out quality grade division.
  2. 2. The method for rapid characterization of photochromic performance of knitted fabric according to claim 1, wherein the phase-locked detection and multidimensional feature extraction step comprises: Calculating an average value I i,DC of the channel signals I i (t) in one or more modulation periods; obtaining an in-phase component X i and a quadrature component Y i of the same-frequency component by multiplying and integrating the modulated reference signal; calculating rising time t rise at the moment of modulating the lamp on, which is the time required for the photoelectric signal to reach the steady state of 90%; The falling time t fall after extinction is calculated to be the time required for the signal to decay to 10% of the initial value; calculating a hysteresis area A hys in a modulation period, wherein the hysteresis area A hys is an area surrounded by a rising and falling curve; Exponential fitting a N = A 0 × exp(-λ short ×n) through the response peak a N of the consecutive multiple modulation periods yields a short-time decay constant λ short as an input feature of the soft measurement model.
  3. 3. The method for rapidly characterizing the photochromic performance of the knitted fabric according to claim 2, wherein the phase-locked detection and multidimensional feature extraction steps further comprise a texture compensation mechanism, wherein spatial uniformity data of each position is collected by the multichannel array through short-time low-intensity scanning before formal testing, a standard plane plate is a barium sulfate standard white plate with the reflectivity of 99%, a calculation formula of a texture compensation coefficient is C tex,i = R std / R i,avg , wherein R std is an average response value of the standard white plate, R i,avg is an average response value of an ith channel on the surface of the knitted fabric, and characteristics of each channel are multiplied by the C tex,i in feature calculation to normalize so as to reduce local dark area and light area differences caused by a knitted coil structure.
  4. 4. The method for rapidly characterizing photochromic performance of a knitted fabric according to claim 1, wherein the closed-loop control algorithm in the step of calibrating the light source plane light intensity in a closed-loop manner is as follows: Wherein I n is the digitally processed LED drive current control quantity, K p is a proportionality coefficient of 0.1-0.5, K i is an integral coefficient of 0.01-0.1, E n,uv,set is the digitally processed target light intensity set value, E n,uv,meas is the digitally processed actual measured illuminance, and the control period is 50ms.
  5. 5. The rapid characterization test method for the photochromic performance of the knitted fabric according to claim 1 is characterized in that in the sample preparation and tension setting step, the knitted fabric sample is subjected to humidity adjustment for at least 4 hours under standard temperature and humidity conditions of 20 ℃ and 65%RH, a four-frame type adjustable tension clamping frame is adopted by the tension control clamping mechanism, and is provided with a motor-screw rod or stepping motor driven fine adjustment mechanism, wherein the preset elongation is any value of 5%, 10% or 15%, and the conditions of slight, moderate and severe stretching are simulated correspondingly; In the dynamic modulation illumination and synchronous sampling step, the peak wavelength of the ultraviolet LED array is 365nm or 395nm, the sampling frequency is 100Hz, the multichannel photoelectric sensing array comprises 4 integrated RGB three-channel color sensors annularly arranged at the position 100mm above a sample, each sensing unit is respectively positioned at azimuth angles of 0 DEG, 90 DEG, 180 DEG and 270 DEG relative to the center of the sample, zenith angles are 45 DEG, and reflected light is observed at different incidence angles and azimuth angles to form multichannel electric signal collection of a three-dimensional reflection field on the surface of the knitted fabric.
  6. 6. The method for rapidly characterizing the photochromic performance of the knitted fabric according to claim 1, wherein in the calculation step of the photochromic performance soft measurement model, a 3-layer feedforward neural network is adopted as the machine learning model, 18 nodes of an input layer correspond to the preprocessed feature vectors, 12 nodes of a hidden layer use a ReLU activation function, 4 nodes of an output layer correspond to delta E ∞,est 、k color,est 、k fade,est 、F fatigue,est , a mean square error loss function MSE= (1/n) sigma (y true - y pred ) 2 and Adam optimizer) is adopted for training, a Z-score standardization method F norm = (F-mu)/sigma is adopted for feature preprocessing, and a training dataset comprises 150 knitted photochromic fabric samples with different formulas and standard long-period test data corresponding to the knitted photochromic fabric samples.
  7. 7. The rapid characterization test method for photochromic performance of knitted fabric according to claim 1, wherein in the rapid evaluation index calculation step, a calculation formula of the photochromic rapid evaluation index Q knit of the knitted fabric is Q knit = α × (ΔE ∞,est /ΔE ref ) + β × (k color,est /k color,ref ) + γ × (F fatigue,ref /F fatigue,est );, Δe ref =20、k color,ref =0.5 s^-1、F fatigue,ref =0.2 is a reference grade sample index, α=0.4, β=0.4, γ=0.2 is a weight coefficient, the photochromic rapid evaluation index is classified into a class a, B class and C class three-level quality grades according to the Q knit value, wherein fatigue terms adopt reciprocal forms to ensure that the smaller the fatigue coefficient is, the higher the evaluation index is, and the threshold can be adjusted through statistical experience on historical samples.
  8. 8. A knitted fabric photochromic performance rapid characterization test device, which adopts the knitted fabric photochromic performance rapid characterization test method according to any one of claims 1 to 7, and is characterized by comprising: the ultraviolet LED array light source module is used for providing ultraviolet irradiation with peak wavelength of 365nm or 395 nm; the closed-loop light intensity control module comprises a reference ultraviolet light intensity sensor, a signal amplifying circuit, an ADC (analog-to-digital converter) and a control processor, and is used for realizing closed-loop control of light intensity and maintaining stability; the tension control clamping mechanism comprises a four-side frame type adjustable tension clamping frame, a motor driving device and a tension sensor, and is used for applying controllable tension to the knitted fabric and keeping the knitted fabric stable; the multi-angle composite photoelectric sensing array comprises a plurality of integrated RGB three-channel color sensors which are annularly arranged and are used for collecting three-dimensional reflection fields on the surface of the knitted fabric and converting the three-dimensional reflection fields into multi-channel electric signals; the data acquisition and signal processing module comprises a multi-channel low-noise amplifier, a multi-channel high-speed ADC and an embedded processor and is used for realizing phase-locked amplification, feature extraction and soft measurement model calculation; the upper computer software and the model library are used for setting test parameters, displaying test results, calling a pre-trained machine learning model and outputting photochromic performance evaluation indexes.
  9. 9. An electronic device, characterized in that the device comprises a processor and a memory for storing a computer program and for transmitting the computer program to the processor, the processor being adapted to execute the method according to instructions in the computer program.
  10. 10. A storage medium storing computer-executable instructions which, when executed by a computer processor, are adapted to perform the method of any one of claims 1-7.

Description

Method and device for rapidly characterizing and testing photochromic performance of knitted fabric Technical Field The application relates to the technical field of intelligent detection and photoelectric measurement of textiles, in particular to a method and a device for rapidly characterizing and testing photochromic performance of knitted fabric. Background Photochromic textiles are functional materials which can change reversible colors under the irradiation of ultraviolet light or light rays with specific wavebands, and are widely applied to scenes such as anti-counterfeiting, intelligent wearing, ultraviolet indication and the like. With the rapid development of intelligent textile technology, photochromic textiles are increasingly applied to the fields of fashion clothing, functional protective articles, outdoor sports equipment and the like. In particular, the knitted fabric becomes an important carrier of photochromic textiles due to good elasticity and comfort. The knitted fabric presents an obvious coil structure, has unique pore distribution and thickness variation characteristics, can generate different degrees of stretching deformation in the actual wearing process, and has important influence on the photochromic performance. Currently, the performance detection of photochromic textiles mainly adopts the following technical routes. The first is a standard light source excitation Method, which adopts standard sunlight or standard D65 light source as excitation light source, and evaluates photochromic performance by measuring chromatic aberration before and after color change and chromatic aberration in the recovery process, and typical standard long period test can refer to AATCC TEST Method 30 or ISO 105-B02 and other existing standards to carry out continuous illumination and dark place recovery, and calculate a chromatic aberration curve changing with time by spectrophotometry. The second is a color-changing performance testing device, which is provided with a standard light source, an ultraviolet lamp, a constant-temperature cold and hot table and a camera, and obtains a change curve of the fabric along with time through image processing, and is used for analyzing the color-changing response speed of the thermosensitive or photosensitive fabric. And thirdly, a special spectrophotometer method is adopted, the spectral accuracy and the theoretical model fitting are emphasized, and a color hysteresis curve is established for performance evaluation. The existing method has the defects that (1) a standard light source excitation method is greatly influenced by environment, fine closed loop control cannot be carried out on light intensity, adaptability to different fabric structures is insufficient, (2) an existing color-changing performance testing device focuses on temperature control and image acquisition, stereoscopic light field distribution of a knitting structure in a stretching and curling state is not compensated, dynamic modulation light and electric phase locking measurement modes are lacked, testing time is relatively long, (3) a special spectrophotometer method generally needs long irradiation and recovery time, equipment is complex and high in cost, small sample testing of fibers and thin fabrics is carried out, on-line or rapid evaluation of large-width knitted fabrics is not friendly enough, 4) the existing detection method is mostly based on flattening, static irradiation and single-angle observation, real photochromic performance of the knitted fabrics under the taking tension is ignored, 5) the existing instrument is mostly used for continuous light irradiation and static color measurement, a dynamic modulation light source and electric synchronous detection are not utilized to improve signal to noise ratio, testing time is shortened, and (6) an algorithm is mostly a traditional color difference calculation model is lacked, and reliable color-changing performance and steady state fatigue performance index is difficult to infer within tens of seconds. In summary, the technical problems of long detection time of the photochromic performance of the knitted fabric, lack of consideration of the characteristics of the knitted structure, lack of tension coupling control and incapability of realizing rapid and accurate prediction exist in the prior art. Disclosure of Invention The invention provides a method and a device for rapidly characterizing and testing the photochromic performance of a knitted fabric, which can realize rapid, quantitative and repeatable characterization of the photochromic performance of the knitted fabric, and solve the technical problems of long testing time, no consideration of the characteristic of a knitted structure and lack of tension coupling in the prior art. According to the method, test conditions of the knitted fabric in a controllable tension state are established through sample preparation and tension setting steps, a knitted fabric sample is arra