CN114812457A - Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method - Google Patents

Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method Download PDF

Info

Publication number
CN114812457A
CN114812457A CN202210741145.1A CN202210741145A CN114812457A CN 114812457 A CN114812457 A CN 114812457A CN 202210741145 A CN202210741145 A CN 202210741145A CN 114812457 A CN114812457 A CN 114812457A
Authority
CN
China
Prior art keywords
pulse laser
eccentricity
angle adjusting
adjusting mechanism
shaft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202210741145.1A
Other languages
Chinese (zh)
Other versions
CN114812457B (en
Inventor
张彦杰
王涛
闫鹏
弓鹏飞
和东平
张金柱
张炜
于程豪
张超
张勇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Taiyuan University of Technology
Original Assignee
Taiyuan University of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Taiyuan University of Technology filed Critical Taiyuan University of Technology
Priority to CN202210741145.1A priority Critical patent/CN114812457B/en
Publication of CN114812457A publication Critical patent/CN114812457A/en
Application granted granted Critical
Publication of CN114812457B publication Critical patent/CN114812457B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G01B17/02—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

The invention belongs to the technical field of metal material thickness measurement, and particularly relates to a laser ultrasonic metal composite plate thickness measuring device and method with self-adjusting light path alignment, the camera coaxial mounting block or the sample clamp is arranged in the middle of the slide rail, the pulse laser CCD camera and the continuous laser CCD camera are respectively arranged on two sides of the camera coaxial mounting block, the pulse laser developing screen and the continuous laser developing screen are respectively arranged in front of the lens of the pulse laser CCD camera and the lens of the continuous laser CCD camera, the pulse laser diaphragm and the continuous laser diaphragm are symmetrically arranged at the left side and the right side of the slide rail, the invention combines the pulse laser CCD camera and the continuous laser CCD camera with the pulse laser diaphragm and the continuous laser diaphragm, the two laser beams can be adjusted to be coaxial within an error range, and the collinear adjustment of only the excitation point and the detection point to the thickness direction is avoided.

Description

Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method
Technical Field
The invention belongs to the technical field of metal material thickness measurement, and particularly relates to a laser ultrasonic metal composite plate thickness measuring device and method with self-adjusting light path alignment.
Background
The metal composite plate can realize the performance requirements which can not be met by single metal, fully exerts the respective advantages of the base material and the multiple layer material and realizes the optimal performance configuration among the materials. The thicknesses of the base layer material and the composite layer material of the metal composite board have important influence on key properties such as strength, electric conductivity and the like of the composite board, so that accurate thickness measurement of the base layer material and the composite layer material has an important effect on service performance evaluation of the composite board.
Common methods for measuring the thickness of the metal composite plate comprise a magnetic method for measuring the thickness, a metallographic method for measuring the thickness and an ultrasonic method for measuring the thickness. The magnetic method thickness measurement is to measure the thickness of a non-magnetic coating on a magnetic substrate by using a magnetic induction principle, the thickness is seriously influenced by the magnetic change of a substrate metal, and the surface roughness of a measured target can cause system errors and accidental errors; although the thickness measurement by the metallographic method is visual and has high measurement precision, the procedures of cutting, sampling, polishing and the like need to be carried out on a detection target, the process is complicated, the real-time performance is not realized, the sampling point for the detection target is limited, and the comprehensive detection cannot be realized; the ultrasonic thickness measurement is based on the ultrasonic pulse reflection principle, and has the advantages of good real-time performance, wide detectable range, high precision and the like. However, ultrasonic pulses generated by the conventional piezoelectric probe are wide in time domain, and when the ultrasonic pulses are transmitted in the composite layer of the composite plate, aliasing of echoes on the time domain is easily generated, so that time information of multiple echoes is difficult to distinguish, and the thickness of each layer of the composite plate cannot be effectively calculated.
Compared with the traditional piezoelectric ultrasound, the ultrasonic pulse excited by the pulse laser has a narrow time domain width, is particularly suitable for the thickness measurement of a thin plate, is a full-optical non-contact high-time/space-resolution nondestructive detection technology, does not need a coupling agent in the detection process, and is also suitable for the nondestructive detection of high-temperature and moving targets compared with the traditional piezoelectric ultrasound.
Laser ultrasound generally uses a pulsed laser as an excitation source of ultrasonic waves, and the pulsed laser can simultaneously excite waveforms such as longitudinal waves, transverse waves, and surface waves in a solid material by a thermoelastic or ablation effect. Where the surface wave propagates along the surface of the material, the excitation and reception of the surface wave is typically done on the same side of the sample being measured. However, longitudinal waves and transverse waves belong to bulk waves, and particularly longitudinal waves excited by ablation effect, are generally used for thickness detection because the direction of the highest waveform energy is the normal direction of the material surface. The excitation and the reception of the longitudinal wave can be on the same side of the sample to be detected, and can also be on the different side of the sample to be detected, when the excitation and the reception are on the same side of the sample, the excitation laser and the detection laser only need to be adjusted to be coincident through naked eyes. However, when the ultrasonic wave is excited and received on the opposite side of the sample, it is difficult to ensure the coaxiality of the two laser beams only by visual observation, so that the excitation point and the receiving point of the ultrasonic wave cannot be kept collinear in the thickness direction of the sample, and the actual propagation path of the ultrasonic wave is greater than the thickness of the sample. If the eccentricity between the excitation point and the detection point occurs when the sample side is thick, the measurement result of the thickness will be large, and thus it can be seen that the eccentricity between the excitation point and the detection point has a direct influence on the accuracy of the measurement result.
If the collinearity of the excitation point and the detection point in the sample thickness direction is only adjusted before measurement, and the coaxiality of the excitation laser and the detection laser is not adjusted, the axial direction of the excitation laser and the axial direction of the detection laser form a certain included angle, if test samples with different thicknesses are replaced or the size of an excitation light spot is adjusted, the excitation point and the detection point generate position deviation again, and the alignment needs to be adjusted again. Therefore, in order to ensure the applicability of the light path under different sample thicknesses, the excitation laser and the detection laser on two sides of the sample must be adjusted to be coaxial before measurement, which has very important significance for improving the thickness measurement precision and the measurement stability of laser ultrasound.
Disclosure of Invention
Aiming at the problems, the invention provides a laser ultrasonic metal composite plate thickness measuring device and method with self-adjusting light path alignment.
In order to achieve the purpose, the invention adopts the following technical scheme:
the light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device comprises an operation platform, a slide rail, a camera coaxial mounting block, a sample clamp, a pulse laser CCD camera, a continuous laser CCD camera, a pulse laser developing screen, a continuous laser developing screen, a pulse laser diaphragm, a continuous laser diaphragm, a first angle adjusting mechanism, a second angle adjusting mechanism, a first reflecting mirror, a second reflecting mirror, a pulse laser and an optical interferometer, wherein the slide rail is mounted on the operation platform, the camera coaxial mounting block or the sample clamp is mounted in the middle of the slide rail, the camera coaxial mounting block is used for self-adjusting alignment errors of light paths, the sample clamp is used for clamping metal composite plates when the thickness of the metal composite plates is measured, the pulse laser CCD camera and the continuous laser CCD camera are respectively mounted on two sides of the camera coaxial mounting block, and the pulse laser developing screen and the continuous laser developing screen are respectively mounted on lenses of the pulse laser CCD camera and the continuous laser CCD camera It is preceding, pulse laser diaphragm and continuous laser diaphragm symmetry are installed in the left and right sides of slide rail, and corresponding with pulse laser CCD camera and continuous laser CCD camera respectively pulse laser diaphragm and continuous laser diaphragm's the outside is installed two angle adjustment mechanism a angle adjustment mechanism is installed to two angle adjustment mechanism's the place ahead or rear, an angle adjustment mechanism and two angle adjustment mechanism all install on operation platform, a speculum and No. two speculums are installed respectively on an angle adjustment mechanism and two angle adjustment mechanism, pulse laser and optical interferometer are installed to an angle adjustment mechanism's inboard, and wherein pulse laser and pulse laser diaphragm homonymy, optical interferometer are in continuous laser diaphragm homonymy, line and a speculum and pulse laser between two speculums and the pulse laser development screen/continuous laser development screen between The connecting lines between the two are parallel.
Furthermore, the pulse laser diaphragm and the continuous laser diaphragm are arranged on the slide rail through telescopic support rods.
Still further, the first angle adjusting mechanism and the second angle adjusting mechanism are the same in structure, the first angle adjusting mechanism comprises a fixing rod, a mounting seat is arranged on the fixing rod, and a mounting seat is fixedly arranged on the mounting seatYShaft support frame inYThe outer side of the shaft support frame is fixed withYShaft rotating electric machine inYAn output shaft of the shaft rotating motor is fixedly provided withYA shaft rotating shaft, saidYThe shaft rotating shaft is rotatably mounted onYOn the shaft support frameYThe shaft rotating shaft is fixedly provided withYShaft adjusting block atYThe shaft adjusting block is fixedly provided withXShaft support frame inXThe outer side of the shaft support frame is fixed withXShaft rotating electric machine inXAn output shaft of the shaft rotating motor is fixedly provided withXA shaft rotating shaft, saidXThe shaft rotating shaft is rotatably mounted onXOn the shaft support frameXA first reflector is fixedly arranged on the shaft rotating shaft.
The method for measuring the thickness of the laser ultrasonic metal composite plate by self-adjusting light path alignment comprises the following steps:
step 1, a pulse laser diaphragm, a camera coaxial installation block and a continuous laser diaphragm are sequentially installed on a slide rail, the camera coaxial installation block is installed at the center position of the slide rail, a pulse laser CCD camera and a continuous laser CCD camera are respectively installed on two sides of the camera coaxial installation block, the pulse laser CCD camera and the pulse laser diaphragm are located on the same side of the camera coaxial installation block, the continuous laser CCD camera and the continuous laser diaphragm are located on the same side of the camera coaxial installation block, and a pulse laser developing screen and a continuous laser developing screen are respectively installed in front of lenses of the pulse laser CCD camera and the continuous laser CCD camera;
step 2, calibrating the pulse laser side light path, comprising the following steps:
step 2.1, calibrating the image center of the pulse laser CCD cameraO，The imaging area of the pulse laser CCD camera adopts a Cartesian coordinate system, and the origin of the imaging area is the image centerOThe reference point is used for providing a reference point for the adjustment of the position of the light spot;
step 2.2, setting the roundness coefficient threshold of the light spot asδ 0 Center of light spotO 1 Deviating from the image center of the pulse laser CCD cameraOHas an eccentricity threshold ofβ 0 ；
Step 2.3, adjusting the axis position of the pulse laser diaphragm to enable the axis position to coincide with the axis of the pulse laser CCD camera, and specifically comprising the following steps:
step 2.3.1, manually and coarsely adjusting the position of the pulse laser diaphragm by changing the length of a support rod below the pulse laser diaphragm, so that the center line of the pulse laser diaphragm and the center line of a pulse laser CCD camera are approximately in the same horizontal plane;
step 2.3.2, starting the pulse laser CCD camera, irradiating the pulse laser diaphragm by using a parallel light source superposed on the geometric axis of the pulse laser CCD camera to enable the light spot to fall on the pulse laser video screen, and calculating the coordinate of the geometric center point of the light spotO 1 (x 0 , y 0 ) The specific calculation steps are as follows:
a1, acquiring an image on a pulse laser development screen through a pulse laser CCD camera, and carrying out binarization processing on the acquired image to completely reserve a light spot area;
step a2, extracting contour information of the spot image after binarization processing, recording the contour information as phi, and recording the contour edgeXAbscissa and ordinate of maximum point of coordinate values in the axial direction ((S))x 1 , y 1 ) As the starting point for curvature and curvature radius calculation;
step a3, calculating Φ st by the following equation in a counterclockwise direction from the start pointiCurvature at pointK i ：
Figure 583156DEST_PATH_IMAGE001
（1）
(x i , y i ) Is as followsiCoordinates of points;
step a4, analyzing curvature at each point phiK i And calculating the coordinates of the central point of the light spot as follows:
(i) curvature at each point of phiK i The method has the advantages that the mutation point does not exist, namely the light spot completely passes through the central hole of the pulse laser diaphragm and falls on the pulse laser developing screen, and the coordinates of the central point of the light spot are calculated according to the following formula:
Figure 116906DEST_PATH_IMAGE002
（2）
whereinSRepresenting the area of the light spot in the pulsed laser CCD camera image,nrepresents the number of discrete points of the light spot profile,x i 、y i represents the firstiThe horizontal and vertical coordinates of each discrete point;
Figure 374712DEST_PATH_IMAGE003
（3）
(ii) if curvatureK i When the coordinates of the center point of the light spot are calculated, the coordinates A of the two curvature mutation points need to be extracted (the coordinates A are calculated)xx 1 , yy 1 ) And B (a), (B)xx 2 , yy 2 ) And calculating the curvature radius of two sections of circular arcs on the pulse laser developing screen, namely the curvature radius of the light spot and the curvature radius of the light spot projection:
Figure 335715DEST_PATH_IMAGE004
（4）
whereinK 1 ＞K 2 ，K 1 Which is the curvature of the spot itself,K 2 is the curvature of the projection of the light spot, wherein A: (xx 1 , yy 1 ) Is always maintained at B: (xx 2 , yy 2 ) On the right side of the frame,R 1 indicating the radius of curvature of the spot itself,R 2 a radius of curvature representing a projection of the spot;
to calculateO 1 (x 0 , y 0 ) The absolute coordinates in the imaging area of the pulsed laser CCD camera, i.e. in the cartesian coordinate system, need to be calculated first a: (xx 1 , yy 1 ) And B (a), (B)xx 2 , yy 2 ) A midpoint C of (xx 3 , yy 3 ) Coordinates are as follows:
Figure 311761DEST_PATH_IMAGE005
（5）
by the central point of the light spotO 1 (x 0 , y 0 ) Establishing a sub-coordinate system for the origin, in which sub-coordinate system the origin is determined byO 1 C、O 1 The geometrical relationship between A and AC can be listed as follows:
Figure 649201DEST_PATH_IMAGE006
（6）
solving the above equation, if C: (xx 3 , yy 3 ) In the first quadrant of the sub-coordinate system, then (x 0 , y 0 ) Can be expressed as:
Figure 558252DEST_PATH_IMAGE007
（7a）
if C (C: (C))xx 3 , yy 3 ) In the second quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be used forExpressed as:
Figure 893418DEST_PATH_IMAGE008
（7b）
if C (C: (C))xx 3 , yy 3 ) In the third quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 153498DEST_PATH_IMAGE009
（7c）
if C (C: (C))xx 3 , yy 3 ) In the fourth quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 29050DEST_PATH_IMAGE010
（7d）
step 2.3.3, according to the calculated coordinates of the geometric center point of the light spot, the pulse laser diaphragm is finely adjusted through a fine adjustment mechanism on the pulse laser diaphragm, so that the center point of the light spot is finely adjustedO 1 With the centre of the imageOCoincidence to eccentricity of spot centerβSatisfies the following conditions:
Figure 261448DEST_PATH_IMAGE011
（8）
degree of eccentricityβThe calculation formula of (2) is as follows:
Figure 564254DEST_PATH_IMAGE012
（9）
wherein (A) and (B)x 0 , y 0 ) Representing the geometric center point coordinates of the light spot;
step 2.4, fixing the slide rail on an operation platform, and installing a pulse laser, a first angle adjusting mechanism and a second angle adjusting mechanism on the operation platform, wherein a first reflector and a second reflector are respectively installed on the first angle adjusting mechanism and the second angle adjusting mechanism, the first reflector and the second reflector are oppositely arranged, the inclination angles of the first reflector and the second reflector are 45 degrees and 135 degrees respectively, and the connecting line between the second reflector and the pulse laser developing screen is parallel to the connecting line between the first reflector and the pulse laser;
step 2.5, starting the pulse laser, manually adjusting the first reflector and the second reflector to enable the pulse laser to completely pass through the pulse laser diaphragm and form a complete light spot on the pulse laser developing screen;
step 2.6, adjusting the pulse laser by adjusting the first reflector and the second reflector to enable the pulse laser to be coaxial with the pulse laser CCD camera, and specifically comprising the following steps:
step 2.6.1, define the first angle adjusting mechanism and the second angle adjusting mechanismYShaft rotating electric machine andXthe positive and negative rotation of the shaft rotating motor specifically comprises the following steps: seen from the end direction of the motor shaft, in the first angle adjusting mechanism and the second angle adjusting mechanismYShaft rotating electric machine andXthe clockwise rotation of the shaft rotating motor is called forward rotation, the anticlockwise rotation is called reverse rotation, the angle is positive when the shaft rotating motor rotates forwards, and the angle is negative when the shaft rotating motor rotates reversely;
step 2.6.2, collecting a light spot image on a pulse laser developing screen through a pulse laser CCD camera, carrying out binarization processing, extracting contour information after binarization processing, and calculating the roundness coefficient of the light spot by using a formula (10)δ；
Figure 514892DEST_PATH_IMAGE013
（10）
WhereinSRepresenting the area of the light spot in the pulsed laser CCD camera image,crepresenting the perimeter of a light spot in a pulsed laser CCD camera image;
Figure 194135DEST_PATH_IMAGE014
（11）
Figure 77778DEST_PATH_IMAGE015
（12）
step 2.6.3, judging the roundness coefficient of the current light spotδIf, ifδ≤δ 0 Then, the center coordinates of the current light spot are calculated by using the formula (2)O 1 (x 0 , y 0 ) If, ifδ＞δ 0 Then, the center coordinates of the current spot are calculated by using the formula (7 a), (7 b), (7 c) or (7 d)O 1 (x 0 , y 0 )；
Step 2.6.4, calculating the eccentricity of the current light spot by using the formula (9), if the eccentricity is not calculated, calculating the eccentricity of the current light spotβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Adjusting the position of the light spot;
step 2.6.5, adjust the current light spot andXthe deviation of the shaft comprises the following specific steps:
b1, recording the current spot centerO 1 In the quadrant of the Cartesian coordinate system, and reading the current eccentricityβ；
b2, defining the motor rotation direction coefficientM、NWhereinMFor indicating an angle adjusting mechanismXShaft rotating electric machine andYthe rotation direction coefficient of the shaft rotating motor,Nfor indicating angle adjustment mechanism of two numbersXShaft rotating electric machine andYthe rotation direction coefficient of the shaft rotating motor,M、Nis selected from 1 and-1, 1 and-1 respectively represent forward rotation and reverse rotation, if the central coordinate of the light spotO 1 In the first or second quadrant, the definition is initializedM=1、N= -1, if central coordinate of light spotO 1 In the third or fourth quadrant, the definition is initializedM=1、N=1；
b3, calculating the current pulse laser beam andXangle of horizontal plane of axisθ x ：
Figure 489167DEST_PATH_IMAGE016
（13）
Whereinl 2 Represents the horizontal distance between the second reflecting mirror and the pulse laser developing screen,y 0 is the ordinate of the light spot center;
in the second angle adjusting mechanismXStep rotation angle Δ of shaft rotating motorθ x2 Comprises the following steps:
Figure 458260DEST_PATH_IMAGE017
（14）
in a first angle adjusting mechanismXStep rotation angle Δ of shaft rotating motorθ x1 Comprises the following steps:
Figure 941194DEST_PATH_IMAGE018
（15）
whereinl 1 The distance between the first reflector and the second reflector is represented;
b4 recording the current eccentricity of the light spot asβ 1 In defining an angle adjustment mechanismXStep rotation angle of shaft rotation motorMΔθ x1 In a second angle adjusting mechanismXStep rotation angle of shaft rotation motorNΔθ x2 ；
b5 in Angle-adjusting mechanismXRotation of shaft rotating electric machineMΔθ x1 In the primary and secondary angle adjusting mechanismXThe shaft rotating motor rotates in successive steps, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer reduced;
b6, judging the current eccentricityβWhether less than the eccentricity recorded in step b4β 1 If, ifβ≥β 1 In an angle adjusting mechanismXThe rotating direction of the shaft rotating motor is wrong, so thatM= -1, repeat step b5 untilβ＜β 1 (ii) a If it isβ＜β 1 Then an angle of oneIn the adjusting mechanismXThe shaft rotating motor has correct rotating direction and enters the next step;
b7, judging the current eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Then, the adjustment is continued, in the first angle adjusting mechanismXRotation of shaft rotating electric machineMΔθ x1 In the primary and secondary angle adjusting mechanismXThe shaft rotating motor rotates in a continuous stepping manner, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
b8, judging the current eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Entering the next step;
b9, if the current spot centerO 1 The quadrant comparison step b1 is changed, and the operation is stoppedXAdjustment of the axis deviation if the current spot centerO 1 If the quadrant is not changed compared with the step b1, returning to the step b 7;
step 2.6.6, judging the current eccentricityβIf, ifβ≤β 0 If so, the adjustment is finished; if it isβ＞β 0 Then adjust the current spot andYthe deviation of the shaft comprises the following specific steps:
c1, recording the current spot centerO 1 In the quadrant of the Cartesian coordinate system, and reading the current eccentricityβ；
c2, if the center coordinate of the current light spotO 1 In the first or fourth quadrant, the definition is initializedM=1、N=1, if the center coordinates of the light spotO 1 In the second or third quadrant, the definition is initializedM=1、N=-1；
c3, calculating the current pulse laser beam andYangle of horizontal plane of axisθ y ：
Figure 882605DEST_PATH_IMAGE019
（16）
x 0 The abscissa is the center of the light spot;
in the second angle adjusting mechanismYStep rotation angle Δ of shaft rotating motorθ y2 Comprises the following steps:
Figure 792793DEST_PATH_IMAGE020
（17）
in a first angle adjusting mechanismYStep rotation angle Δ of shaft rotating motorθ y1 ：
Figure 249182DEST_PATH_IMAGE021
（18）
c4, recording the current eccentricity of the light spotβ 2 In the system definition-angle adjustment mechanismYStep rotation angle of shaft rotation motorMΔθ y1 In a second angle adjusting mechanismYStep rotation angle of shaft rotation motorNΔθ y2 ；
c5 in angle-adjusting mechanismYRotation of shaft rotating electric machineMΔθ x1 In the primary and secondary angle adjusting mechanismYThe shaft rotating motor rotates in successive steps, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
c6, determining eccentricityβWhether less than the eccentricity recorded in step c4β 2 If, ifβ≥β 2 In an angle adjusting mechanismYThe rotating direction of the shaft rotating motor is wrong, so thatM= -1, re-rotation ifβ＜β 1 In an angle adjusting mechanismYThe shaft rotating motor has correct rotating direction and enters the next step;
c7, judging eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Then, the adjustment is continued, in the first angle adjusting mechanismYRotation of shaft rotating electric machineMΔθ y1 In the primary and secondary angle adjusting mechanismYThe shaft-rotating motor rotates in successive steps, each stepNΔθ y2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
c8, judging eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Entering the next step;
c9, if the current spot centerO 1 The quadrant comparison step c1 is changed, and the operation is stoppedYAdjustment of the axis deviation if the current spot centerO 1 If the quadrant is not changed compared with the step c1, returning to the step c 7;
step 2.6.7, determining the current eccentricityβIf, ifβ＞β 0 Then return to step c7 ifβ≤β 0 If so, the adjustment is finished;
step 3, repeating the step 2, and calibrating the continuous laser side light path;
step 4, sequentially removing the pulse laser CCD camera, the continuous laser CCD camera and the camera coaxial mounting block, mounting a sample clamp at the position where the camera coaxial mounting block is located, and clamping a metal composite plate on the sample clamp, wherein the base layer of the metal composite plate faces the pulse laser, and the multiple layers of the metal composite plate face the continuous laser of the interferometer;
and 5, acquiring laser ultrasonic signals of the metal composite plate, and respectively calculating the thicknesses of the composite layer and the base layer.
Further, in the step 5, the laser ultrasonic signal of the metal composite plate is obtained, and the specific steps of calculating the thicknesses of the composite layer and the base layer respectively are as follows:
step 5.1, starting a pulse laser, exciting ultrasonic waves by the pulse laser at the base layer of the metal composite plate, wherein the ultrasonic waves are transmitted to the interface between the base layer and the multiple layer due to the difference of acoustic impedances of the materials of the multiple layer and the base layerThen, an optical interferometer receives ultrasonic echo signals in the metal composite plate in a multi-layer mode, direct longitudinal waves I, interface primary reflected waves II and top surface primary reflected waves III are respectively marked, and the occurrence time of the direct longitudinal waves I, the interface primary reflected waves II and the top surface primary reflected waves III in the signals is extractedt Ⅰ 、t Ⅱ 、t Ⅲ From this, the thickness of the multilayer is calculated:
Figure 207911DEST_PATH_IMAGE022
（19）
in the above formula, the first and second carbon atoms are,h 1 the thickness of the multi-layer is the thickness of the multi-layer,v 1 the propagation speed of the direct longitudinal wave in the multiple layers;
step 5.2, the thickness of the metal composite plate is formed by the thickness of the base layer and the thickness of the compound layer, and the following equation can be listed according to the propagation time of the ultrasonic waves in the base layer and the compound layer:
Figure 331724DEST_PATH_IMAGE023
（20）
in the above formula, the first and second carbon atoms are,h 2 is the thickness of the base layer,v 2 the propagation speed of the ultrasonic longitudinal wave in the base layer is shown;
the thickness of the base layer of the composite panel can be derived from equation (20):
Figure 350496DEST_PATH_IMAGE024
（21）。
still further, up to eccentricity in said steps b5 and b7βNo longer decreases: in particular to a second angle adjusting mechanismXThe shaft rotating motor rotates in a continuous stepping manner in eccentricityβIn the process of continuously reducing, eccentricity occursβIn the case of increasing, the eccentricity at the turning point is determinedβPoints no longer reduced, then in angle-adjusting mechanisms of twoXShaft rotating electric machineReverse rotation to eccentricityβA corner point; up to eccentricity in said c5 and c7βNo longer decreases: in particular to a second angle adjusting mechanismYThe shaft rotating motor rotates in a continuous stepping manner in eccentricityβIn the process of continuously reducing, eccentricity occursβIn the case of increasing, the eccentricity at the turning point is determinedβPoints no longer reduced, in subsequent angle-adjusting mechanisms of two degreesYThe shaft rotating motor rotates reversely to eccentricityβAt the point of inflection.
Compared with the prior art, the invention has the following advantages:
1. the invention adopts the all-optical non-contact laser ultrasonic method to measure the thickness of each layer of the metal composite plate, and avoids the measurement error caused by the different axes of the light path through the self-adjustment of the light path alignment error;
2. when the thickness is measured, the pulse laser for exciting the ultrasonic waves and the continuous laser for detecting the ultrasonic waves are respectively positioned at two sides of a detection target, and the ultrasonic waves are excited at a base layer and detected in a multiple layer of the metal composite plate, so that the narrow pulse characteristic of the laser ultrasonic waves in a time domain is fully utilized;
3. the pulse laser CCD camera and the continuous laser CCD camera are adopted when the light beam coaxiality is adjusted, and the coaxial pulse laser CCD camera and the coaxial continuous laser CCD camera are utilized, so that the light spot position can be identified with high precision, two laser beams can be prevented from entering the laser of the other laser mutually during adjustment, and the laser is protected;
4. the invention determines the position of the light spot through image recognition and utilizesXShaft rotating electric machine andYthe shaft rotating motor adjusts the angles of the first reflecting mirror and the second reflecting mirror, so that the problems of low manual adjusting efficiency and poor precision are solved;
5. according to the invention, through the combination of the pulse laser CCD camera and the continuous laser CCD camera, the pulse laser diaphragm and the continuous laser diaphragm, two beams of laser can be adjusted to be coaxial within an error range, and the collinearity that only the excitation point and the detection point are adjusted to the thickness direction is avoided, so that the light path alignment does not need to be readjusted when samples with different thicknesses are replaced or the sizes of light spots are adjusted, and the method has an important effect on improving the detection precision and the detection efficiency.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of the installation of the coaxial camera mounting block, the pulsed laser diaphragm and the continuous laser diaphragm of the present invention;
FIG. 3 is a schematic structural view of an angle adjustment mechanism according to the present invention;
FIG. 4 is a schematic diagram of an imaging area of a pulsed laser CCD camera according to the present invention;
FIG. 5 shows the curvature of the CCD camera according to the present inventionK i Schematic of the image when there are two discontinuities.
Detailed Description
In order to further illustrate the technical solution of the present invention, the present invention is further illustrated by the following examples.
As shown in fig. 1 to 3, the laser ultrasonic metal composite plate thickness measuring device with self-adjusting light path alignment comprises an operation platform, a slide rail 1, a camera coaxial installation block 2, a sample clamp, a pulse laser CCD camera 3, a continuous laser CCD camera 4, a pulse laser developing screen 5, a continuous laser developing screen 6, a pulse laser diaphragm 7, a continuous laser diaphragm 8, a first angle adjusting mechanism 9, a second angle adjusting mechanism 10, a first reflecting mirror 11, a second reflecting mirror 12, a pulse laser 13 and an optical interferometer 14, wherein the slide rail 1 is installed on the operation platform, the camera coaxial installation block 2 or the sample clamp is installed in the middle of the slide rail 1, the camera coaxial installation block 2 is used for self-adjusting alignment errors of the light path, the sample clamp is used for clamping a metal composite plate when the metal composite plate thickness is measured, the pulse laser CCD camera 3 and the continuous laser CCD camera 4 are respectively installed on two sides of the camera coaxial installation block 2 through a telescopic support rod 15, the pulse laser developing screen 5 and the continuous laser developing screen 6 are respectively installed in front of lenses of a pulse laser CCD camera 3 and a continuous laser CCD camera 4, the pulse laser diaphragm 7 and the continuous laser diaphragm 8 are symmetrically installed on the left side and the right side of the sliding rail 1 and respectively correspond to the pulse laser CCD camera 3 and the continuous laser CCD camera 4, two angle adjusting mechanisms 10 are installed on the outer sides of the pulse laser diaphragm 7 and the continuous laser diaphragm 8, one angle adjusting mechanism 9 is installed in front of or behind the two angle adjusting mechanisms 10, the one angle adjusting mechanism 9 and the two angle adjusting mechanism 10 are both installed on an operation platform, the first reflecting mirror 11 and the second reflecting mirror 12 are respectively installed on the one angle adjusting mechanism 9 and the two angle adjusting mechanism 10, a pulse laser 13 and an optical interferometer 14 are installed on the inner side of the one angle adjusting mechanism 9, wherein the pulse laser 13 is arranged at the same side of the pulse laser diaphragm 7, the optical interferometer 14 is arranged at the same side of the continuous laser diaphragm 8, and a connecting line between the second reflecting mirror 12 and the pulse laser developing screen 5/the continuous laser developing screen 6 is parallel to a connecting line between the first reflecting mirror 11 and the pulse laser 13/the optical interferometer 14.
The first angle adjusting mechanism 9 and the second angle adjusting mechanism 10 have the same structure, the first angle adjusting mechanism 9 comprises a fixing rod 901, a mounting seat 902 is arranged on the fixing rod 901, and a mounting seat 902 is fixedly arranged on the mounting seat 902YShaft support 903 in the aboveYThe outside of the shaft support 903 is fixed withYShaft rotating electric machine 904 described aboveYAn output shaft of the shaft rotating motor 904 is fixedly provided withYThe shaft rotates a shaft 905, theYThe shaft rotating shaft 905 is rotatably mounted onYOn the shaft support 903, on the shaft supportYThe shaft rotating shaft 905 is fixedly provided withYShaft adjusting block 906 in the shaftYThe shaft adjusting block 906 is fixedly provided withXShaft support 907 in saidXThe outside of the shaft support frame 907 is fixed withXShaft rotating electric machine 908 in the aboveXAn output shaft of the shaft rotating motor 908 is fixedly provided withXShaft rotating shaft 909XThe shaft rotary shaft 909 is rotatably mounted onXOn the shaft support 907, on the saidXA first mirror 11 is fixedly mounted on the shaft rotation shaft 909.
The method for measuring the thickness of the laser ultrasonic metal composite plate by self-adjusting light path alignment comprises the following steps:
step 1, a pulse laser diaphragm 7, a camera coaxial installation block 2 and a continuous laser diaphragm 8 are sequentially installed on a slide rail 1, the camera coaxial installation block 2 is installed at the center position of the slide rail 1, a pulse laser CCD camera 3 and a continuous laser CCD camera 4 are respectively installed on two sides of the camera coaxial installation block 2, the pulse laser CCD camera 3 and the pulse laser diaphragm 7 are located on the same side of the camera coaxial installation block 2, the continuous laser CCD camera 4 and the continuous laser diaphragm 8 are located on the same side of the camera coaxial installation block 2, and a pulse laser developing screen 5 and a continuous laser developing screen 6 are respectively installed in front of lenses of the pulse laser CCD camera 3 and the continuous laser CCD camera 4;
step 2, calibrating the pulse laser side light path, comprising the following steps:
step 2.1, calibrating the image center of the pulse laser CCD camera 3O，The imaging area of the pulse laser CCD camera 3 adopts a Cartesian coordinate system, and the origin of the imaging area is the image centerOThe reference point is used for providing a reference point for the adjustment of the position of the light spot;
step 2.2, setting the roundness coefficient threshold of the light spot asδ 0 Center of light spotO 1 Deviating from the image center of the pulse laser CCD camera 3OHas an eccentricity threshold ofβ 0 ；
Step 2.3, adjusting the axis position of the pulse laser diaphragm 7 to enable the axis position to coincide with the axis of the pulse laser CCD camera 3, and specifically comprising the following steps:
step 2.3.1, manually and coarsely adjusting the position of the pulse laser diaphragm 7 by changing the length of a support rod below the pulse laser diaphragm 7, so that the center line of the pulse laser diaphragm 7 and the center line of the pulse laser CCD camera 3 are approximately in the same horizontal plane;
step 2.3.2, the pulse laser CCD camera 3 is started, the parallel light source superposed on the geometric axis of the pulse laser CCD camera 3 is utilized to irradiate the pulse laser diaphragm 7, so that the light spot falls on the pulse laser video screen 5, and the geometric center point coordinate of the light spot is calculatedO 1 (x 0 , y 0 ) The specific calculation steps are as follows:
step a1, acquiring an image on a pulse laser development screen 5 through a pulse laser CCD camera 3, and carrying out binarization processing on the acquired image to completely reserve a light spot area;
step a2, extracting contour information of the spot image after binarization processing, recording the contour information as phi, and recording the contour edgeXAxial squareAbscissa and ordinate of maximum point of upward coordinate value: (x 1 , y 1 ) As the starting point for curvature and curvature radius calculation;
step a3, calculating Φ st by the following equation in a counterclockwise direction from the start pointiCurvature at pointK i ：
Figure 294181DEST_PATH_IMAGE001
（1）
(x i , y i ) Is as followsiCoordinates of points;
step a4, analyzing curvature at each point phiK i And calculating the coordinates of the central point of the light spot as follows:
(i) curvature at each point of phiK i The method has no mutation point, namely the light spot completely passes through a central hole of the pulse laser diaphragm 7 and falls on the pulse laser development screen 5, and the coordinates of the central point of the light spot are calculated according to the following formula:
Figure 853338DEST_PATH_IMAGE025
（2）
whereinSRepresenting the area of the light spot in the image of the pulsed laser CCD camera 3,nrepresents the number of discrete points of the light spot profile,x i 、y i represents the firstiThe horizontal and vertical coordinates of each discrete point;
Figure 769342DEST_PATH_IMAGE026
（3）
(ii) if curvatureK i Two mutation points exist, namely, only part of the light spot passes through the central hole of the pulse laser diaphragm 7, and the rest part of the light spot is projected to the pulse laser developing screen 5 through the pulse laser diaphragm 7, so that the coordinates A (A) of the two curvature mutation points need to be extracted when the coordinates of the central point of the light spot are calculatedxx 1 , yy 1 ) And B (a), (B)xx 2 , yy 2 ) And calculating the curvature radius of two sections of circular arcs on the pulse laser developing screen 5, namely the curvature radius of the light spot and the curvature radius of the light spot projection:
Figure 21332DEST_PATH_IMAGE004
（4）
whereinK 1 ＞K 2 ，K 1 Which is the curvature of the spot itself,K 2 is the curvature of the projection of the light spot, wherein A: (xx 1 , yy 1 ) Is always kept at B: (xx 2 , yy 2 ) On the right side of the frame,R 1 indicating the radius of curvature of the spot itself,R 2 a radius of curvature representing a projection of the spot;
to calculateO 1 (x 0 , y 0 ) The absolute coordinates in the imaging area of the pulsed laser CCD camera 3, i.e., the absolute coordinates in the cartesian coordinate system, need to be first calculated a (axx 1 , yy 1 ) And B (a), (B)xx 2 , yy 2 ) A midpoint C of (xx 3 , yy 3 ) Coordinates are as follows:
Figure 655575DEST_PATH_IMAGE027
（5）
by the central point of the light spotO 1 (x 0 , y 0 ) Establishing a sub-coordinate system for the origin, in which sub-coordinate system the origin is determined byO 1 C、O 1 The geometrical relationship between A and AC can be listed as follows:
Figure 18424DEST_PATH_IMAGE028
（6）
solving the above equation, if C: (xx 3 , yy 3 ) In the first quadrant of the sub-coordinate system, then (x 0 , y 0 ) Can be expressed as：
Figure 585671DEST_PATH_IMAGE007
（7a）
If C (C: (C))xx 3 , yy 3 ) In the second quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 946245DEST_PATH_IMAGE008
（7b）
if C (C: (C))xx 3 , yy 3 ) In the third quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 864523DEST_PATH_IMAGE009
（7c）
if C (C: (C))xx 3 , yy 3 ) In the fourth quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 968745DEST_PATH_IMAGE029
（7d）
step 2.3.3, according to the calculated coordinates of the geometrical center point of the light spot, the pulse laser diaphragm 7 is finely adjusted through a fine adjustment mechanism on the pulse laser diaphragm 7, so that the center point of the light spot is adjustedO 1 With the center of the imageOCoincidence to eccentricity of spot centerβSatisfies the following conditions:
Figure 921658DEST_PATH_IMAGE011
（8）
degree of eccentricityβThe calculation formula of (2) is as follows:
Figure 249871DEST_PATH_IMAGE012
（9）
wherein (A) and (B)x 0 , y 0 ) Representing the geometric center point coordinates of the light spot;
step 2.4, fixing the sliding rail 1 on an operation platform, installing a pulse laser 13, a first angle adjusting mechanism 9 and a second angle adjusting mechanism 10 on the operation platform, respectively installing a first reflecting mirror 11 and a second reflecting mirror 12 on the first angle adjusting mechanism 9 and the second angle adjusting mechanism 10, wherein the first reflecting mirror 11 and the second reflecting mirror 12 are oppositely arranged, the inclination angles of the first reflecting mirror 11 and the second reflecting mirror 12 are 45 degrees and 135 degrees respectively, and the connecting line between the second reflecting mirror 12 and the pulse laser developing screen 5 is parallel to the connecting line between the first reflecting mirror 11 and the pulse laser 13;
step 2.5, starting a pulse laser 13, manually adjusting a first reflecting mirror 11 and a second reflecting mirror 12 to enable pulse laser to completely pass through a pulse laser diaphragm 7, and forming complete light spots on a pulse laser developing screen 5;
step 2.6, adjusting the pulse laser by adjusting the first reflecting mirror 11 and the second reflecting mirror 12 to enable the pulse laser to be coaxial with the pulse laser CCD camera 3, and specifically comprises the following steps:
step 2.6.1, define the first angle adjusting mechanism 9 and the second angle adjusting mechanism 10YShaft rotating electric machine 904 andXthe forward and reverse rotation of the shaft rotating motor 908 specifically includes: in the first angle adjusting mechanism 9 and the second angle adjusting mechanism 10 viewed from the end direction of the motor shaftYShaft rotating electric machine 904 andXthe clockwise rotation of the shaft rotating motor 908 is called forward rotation, the counterclockwise rotation is called reverse rotation, the angle is positive in the forward rotation, and the angle is negative in the reverse rotation;
step 2.6.2, acquiring a light spot image on a pulse laser developing screen 5 through a pulse laser CCD camera 3, carrying out binarization processing, extracting contour information after binarization processing, and calculating the roundness coefficient of the light spot by using a formula (10)δ；
Figure 593127DEST_PATH_IMAGE030
（10）
WhereinSRepresenting the area of the light spot in the image of the pulsed laser CCD camera 3,crepresenting the perimeter of the light spot in the image of the pulsed laser CCD camera 3;
Figure 297778DEST_PATH_IMAGE031
（11）
Figure 42880DEST_PATH_IMAGE032
（12）
step 2.6.3, judging the roundness coefficient of the current light spotδIf, ifδ≤δ 0 Then, the center coordinates of the current light spot are calculated by using the formula (2)O 1 (x 0 , y 0 ) If, ifδ＞δ 0 Then, the center coordinates of the current spot are calculated by using the formula (7 a), (7 b), (7 c) or (7 d)O 1 (x 0 , y 0 )；
Step 2.6.4, calculating the eccentricity of the current light spot by using the formula (9), if the eccentricity is not calculated, calculating the eccentricity of the current light spotβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Adjusting the position of the light spot;
step 2.6.5, adjust the current light spot andXthe deviation of the shaft comprises the following specific steps:
b1, recording the current spot centerO 1 In the quadrant of the Cartesian coordinate system, and reading the current eccentricityβ；
b2, defining the motor rotation direction coefficientM、NWhereinMFor indicating an angle adjusting mechanism 9XShaft rotating electric machine 908 andYthe rotation direction coefficient of the shaft rotating motor 904,Nfor use in a two-angle adjustment mechanism 10XShaft rotating electric machine 908 andYthe rotation direction coefficient of the shaft rotating motor 904,M、Nis selected from 1 and-1, 1 and-1 respectively represent forward rotation and reverse rotation, if the central coordinate of the light spotO 1 In the first or second quadrant, the definition is initializedM=1、N=1, if the center coordinates of the light spotO 1 In the third or fourth quadrant, the definition is initializedM=1、N=1；
b3, calculating the current pulse laser beam andXangle of horizontal plane of axisθ x ：
Figure 541995DEST_PATH_IMAGE016
（13）
Whereinl 2 Representing the horizontal distance between the mirror number two 12 and the pulsed laser development screen 5,y 0 is the ordinate of the light spot center;
in the second angle adjusting mechanism 10XStep rotation angle Δ of shaft rotating motor 908θ x2 Comprises the following steps:
Figure 434864DEST_PATH_IMAGE017
（14）
in the first angle adjusting mechanism 9XStep rotation angle Δ of shaft rotating motor 908θ x1 Comprises the following steps:
Figure 880889DEST_PATH_IMAGE033
（15）
whereinl 1 Represents the distance between the first mirror 11 and the second mirror 12;
b4 recording the current eccentricity of the light spot asβ 1 Define in an angle adjusting mechanism 9XStep rotation angle of shaft rotation motor 908MΔθ x1 In a second angle adjusting mechanism 10XStep rotation angle of shaft rotation motor 908NΔθ x2 ；
b5 in the first angle adjusting mechanism 9XShaft rotating electric machine 908 rotatesMΔθ x1 In the primary and secondary angle adjusting mechanism 10XThe shaft rotating motor 908 rotates in successive steps, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
b6, judging the current eccentricityβWhether less than the eccentricity recorded in step b4β 1 If, ifβ≥β 1 In the angle adjusting mechanism 9XThe shaft rotating motor 908 has an incorrect rotating directionM= -1, repeat step b5 untilβ＜β 1 (ii) a If it isβ＜β 1 In the angle adjusting mechanism 9XThe shaft rotating motor 908 rotates in the right direction, and the next step is carried out;
b7, judging the current eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Then, the adjustment is continued, in the angle adjusting mechanism 9XShaft rotating electric machine 908 rotatesMΔθ x1 In the primary and secondary angle adjusting mechanism 10XThe shaft rotating motor 908 rotates in successive steps, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
b8, judging the current eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Entering the next step;
b9, if the current spot centerO 1 The quadrant comparison step b1 is changed, and the operation is stoppedXAdjusting the deviation of the axis if the current spot centerO 1 If the quadrant is not changed compared with the step b1, returning to the step b 7;
step 2.6.6, judging the current eccentricityβIf, ifβ≤β 0 If so, the adjustment is finished; if it isβ＞β 0 Then adjust the current spot andYthe deviation of the shaft comprises the following specific steps:
c1, recording the current spot centerO 1 In the quadrant of the Cartesian coordinate system, and reading the current eccentricityβ；
c2, if the center of the current spotCoordinates of the objectO 1 In the first or fourth quadrant, the definition is initializedM=1、N=1, if the center coordinates of the light spotO 1 In the second or third quadrant, the definition is initializedM=1、N=-1；
c3, calculating the current pulse laser beam andYangle of horizontal plane of axisθ y ：
Figure 808394DEST_PATH_IMAGE019
（16）
x 0 The abscissa is the center of the light spot;
in the second angle adjusting mechanism 10YStep rotation angle Δ of shaft rotation motor 904θ y2 Comprises the following steps:
Figure 681672DEST_PATH_IMAGE020
（17）
in the first angle adjusting mechanism 9YStep rotation angle Δ of shaft rotating motor 904θ y1 ：
Figure 530679DEST_PATH_IMAGE021
（18）
c4, recording the current eccentricity of the light spotβ 2 In the system definition-angle adjusting mechanism 9YStep rotation angle of shaft rotation motor 904MΔθ y1 In a second angle adjusting mechanism 10YStep rotation angle of shaft rotation motor 904NΔθ y2 ；
c5 in the first angle adjusting mechanism 9YShaft rotating electric machine 904 rotatesMΔθ x1 In the primary and secondary angle adjusting mechanism 10YThe shaft rotating motor 904 rotates in successive steps, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
c6, judging eccentricityβWhether less than the eccentricity recorded in step c4β 2 If, ifβ≥β 2 In the angle adjusting mechanism 9YThe shaft rotating motor 904 has a wrong rotating directionM= -1, re-rotation ifβ＜β 1 In the angle adjusting mechanism 9YThe shaft rotating motor 904 has the correct rotating direction and enters the next step;
c7, judging eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Then, the adjustment is continued, in the angle adjusting mechanism 9YShaft rotating electric machine 904 rotatesMΔθ y1 In the primary and secondary angle adjusting mechanism 10YThe shaft rotating motor 904 rotates in successive steps, each stepNΔθ y2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
c8, judging eccentricityβWhether or not a stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Entering the next step;
c9, if the current spot centerO 1 The quadrant comparison step c1 is changed, and the operation is stoppedYAdjustment of the axis deviation if the current spot centerO 1 If the quadrant is not changed compared with the step c1, returning to the step c 7;
step 2.6.7, determining the current eccentricityβIf, ifβ＞β 0 Then go back to step c7 ifβ≤β 0 If so, the adjustment is finished;
step 3, repeating the step 2, and calibrating the continuous laser side light path;
step 4, sequentially removing the pulse laser CCD camera 3, the continuous laser CCD camera 4 and the camera coaxial mounting block 2, mounting a sample clamp at the position of the camera coaxial mounting block 2, and clamping a metal composite plate on the sample clamp, wherein the base layer of the metal composite plate faces the pulse laser, and the composite layer of the metal composite plate faces the continuous laser of the interferometer;
step 5, acquiring laser ultrasonic signals of the metal composite plate, and respectively calculating the thicknesses of the composite layer and the base layer, wherein the method specifically comprises the following steps:
step 5.1, starting a pulse laser 13, exciting ultrasonic waves by the pulse laser at a base layer of the metal composite plate, transmitting and reflecting the ultrasonic waves at the interface of the base layer and the compound layer simultaneously due to the difference of acoustic impedances of the compound layer and the base layer, receiving ultrasonic echo signals in the metal composite plate at the compound layer by an optical interferometer 14, respectively marking a direct longitudinal wave I, an interface primary reflected wave II and a top surface primary reflected wave III, and extracting the occurrence time of the direct longitudinal wave I, the interface primary reflected wave II and the top surface primary reflected wave III in the signalst Ⅰ 、t Ⅱ 、t Ⅲ From this, the thickness of the multilayer is calculated:
Figure 842712DEST_PATH_IMAGE022
（19）
in the above formula, the first and second carbon atoms are,h 1 the thickness of the multi-layer is the thickness of the multi-layer,v 1 the propagation speed of the direct longitudinal wave in the multiple layers;
step 5.2, the thickness of the metal composite plate is formed by the thickness of the base layer and the thickness of the compound layer, and the following equation can be listed according to the propagation time of the ultrasonic waves in the base layer and the compound layer:
Figure 562406DEST_PATH_IMAGE023
（20）
in the above formula, the first and second carbon atoms are,h 2 is the thickness of the base layer,v 2 the propagation speed of the ultrasonic longitudinal wave in the base layer is shown;
the thickness of the base layer of the composite panel can be derived from equation (20):
Figure 403323DEST_PATH_IMAGE034
（21）。
up to eccentricity of said steps b5 and b7βNo longer decreases: in particular to a second angle adjusting mechanism 10XThe shaft rotating motor 908 rotates in continuous steps with eccentricityβIn the process of continuously reducing, eccentricity occursβIn the case of increasing, the eccentricity at the turning point is determinedβPoints no longer decreasing, in the subsequent second angle adjustment mechanism 10XShaft rotating electric machine 908 rotates in reverse to eccentricityβA corner point; up to eccentricity in said c5 and c7βNo longer decreases: in particular to a second angle adjusting mechanism 10YThe shaft rotating motor 904 rotates in a continuous step-by-step manner at eccentricityβIn the process of continuously reducing, eccentricity occursβIn the case of increasing, the eccentricity at the turning point is determinedβPoints no longer decreasing, in the subsequent second angle adjustment mechanism 10YShaft rotating electric machine 904 rotates in reverse to eccentricityβAt the point of inflection
While there have been shown and described what are at present considered to be the essential features and advantages of the invention, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims (6)

1. Light path aims at self-adjusting laser supersound metal clad sheet thickness measuring device, its characterized in that: the device comprises an operation platform, a slide rail (1), a camera coaxial mounting block (2), a sample clamp, a pulse laser CCD camera (3), a continuous laser CCD camera (4), a pulse laser developing screen (5), a continuous laser developing screen (6), a pulse laser diaphragm (7), a continuous laser diaphragm (8), an angle adjusting mechanism (9), a second angle adjusting mechanism (10), a reflector (11), a second reflector (12), a pulse laser (13) and an optical interferometer (14), wherein the slide rail (1) is installed on the operation platform, the camera coaxial mounting block (2) or the sample clamp is installed in the middle of the slide rail (1), the camera coaxial mounting block (2) is used for self-adjusting alignment errors of light paths, the sample clamp is used for clamping metal composite plates when the metal composite plates are used for thickness measurement, the pulse laser CCD camera (3) and the continuous laser CCD camera (4) are respectively installed on two sides of the camera coaxial mounting block (2) The pulse laser developing screen (5) and the continuous laser developing screen (6) are respectively installed in front of lenses of the pulse laser CCD camera (3) and the continuous laser CCD camera (4), the pulse laser diaphragm (7) and the continuous laser diaphragm (8) are symmetrically installed on the left side and the right side of the sliding rail (1) and respectively correspond to the pulse laser CCD camera (3) and the continuous laser CCD camera (4), two angle adjusting mechanisms (10) are installed on the outer sides of the pulse laser diaphragm (7) and the continuous laser diaphragm (8), one angle adjusting mechanism (9) is installed in front of or behind the two angle adjusting mechanisms (10), the one angle adjusting mechanism (9) and the two angle adjusting mechanisms (10) are both installed on an operation platform, the one reflecting mirror (11) and the two reflecting mirrors (12) are respectively installed on the one angle adjusting mechanism (9) and the two angle adjusting mechanisms (10), the inner side of the first angle adjusting mechanism (9) is provided with a pulse laser (13) and an optical interferometer (14), wherein the pulse laser (13) is arranged at the same side of the pulse laser diaphragm (7), the optical interferometer (14) is arranged at the same side of the continuous laser diaphragm (8), and a connecting line between the second reflecting mirror (12) and the pulse laser developing screen (5)/the continuous laser developing screen (6) is parallel to a connecting line between the first reflecting mirror (11) and the pulse laser (13)/the optical interferometer (14).
2. The optical alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device of claim 1, wherein: the pulse laser diaphragm (7) and the continuous laser diaphragm (8) are arranged on the sliding rail (1) through a telescopic supporting rod (15).
3. The optical alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device of claim 2, wherein: the first angle adjusting mechanism (9) and the second angle adjusting mechanism (10) are identical in structure, the first angle adjusting mechanism (9) comprises a fixing rod (901), an installation seat (902) is arranged on the fixing rod (901), and the installation seat (902) is fixedly arranged on the installation seat (902)YA shaft support (903) at the shaftYThe outside of the shaft support frame (903) is fixed withYA shaft rotating electric machine (904) in the aboveYAn output shaft of the shaft rotating motor (904) is fixedly provided withYA shaft rotation shaft (905), saidYThe shaft rotating shaft (905) is rotatably arranged onYOn the shaft support (903) on the shaftYThe shaft rotating shaft (905) is fixedly provided withYA shaft adjusting block (906) at the shaftYThe shaft adjusting block (906) is fixedly provided withXShaft support (907) in saidXThe outer side of the shaft support frame (907) is fixed withXA shaft rotating electric machine (908) in the motorXAn output shaft of the shaft rotating motor (908) is fixedly provided withXA shaft rotating shaft (909), saidXThe shaft rotating shaft (909) is rotatably arranged onXOn the shaft support (907), on the saidXA first reflector (11) is fixedly arranged on the shaft rotating shaft (909).
4. A method for measuring the thickness of a metal composite plate by using the device of claim 3, which is characterized by comprising the following steps: the method comprises the following steps:
step 1, a pulse laser diaphragm (7), a camera coaxial installation block (2) and a continuous laser diaphragm (8) are sequentially installed on a slide rail (1), the camera coaxial installation block (2) is installed at the center of the slide rail (1), a pulse laser CCD camera (3) and a continuous laser CCD camera (4) are respectively installed on two sides of the camera coaxial installation block (2), the pulse laser CCD camera (3) and the pulse laser diaphragm (7) are located on the same side of the camera coaxial installation block (2), the continuous laser CCD camera (4) and the continuous laser diaphragm (8) are located on the same side of the camera coaxial installation block (2), and a pulse laser development screen (5) and a continuous laser development screen (6) are respectively installed in front of lenses of the pulse laser CCD camera (3) and the continuous laser CCD camera (4);
step 2, calibrating the pulse laser side light path, comprising the following steps:
step 2.1, calibrating the image center of the pulse laser CCD camera (3)O，The imaging area of the pulse laser CCD camera (3) adopts a Cartesian coordinate system, and the origin of the imaging area is the image centerOThe reference point is used for providing a reference point for the adjustment of the position of the light spot;
step 2.2, setting the roundness coefficient threshold of the light spot asδ 0 Center of light spotO 1 Deviates from the image center of the pulse laser CCD camera (3)OHas an eccentricity threshold ofβ 0 ；
Step 2.3, adjusting the axis position of the pulse laser diaphragm (7) to enable the axis position to coincide with the axis of the pulse laser CCD camera (3), and specifically comprising the following steps:
step 2.3.1, manually and roughly adjusting the position of the pulse laser diaphragm (7) by changing the length of a support rod below the pulse laser diaphragm (7) to enable the center line of the pulse laser diaphragm and the center line of the pulse laser CCD camera (3) to be approximately in the same horizontal plane;
step 2.3.2, the pulse laser CCD camera (3) is started, a parallel light source which is superposed on the geometric axis of the pulse laser CCD camera (3) is used for irradiating a pulse laser diaphragm (7), so that light spots fall on a pulse laser developing screen (5), and the coordinate of the geometric center point of the light spots is calculatedO 1 (x 0 , y 0 ) The specific calculation steps are as follows:
a1, acquiring an image on a pulse laser development screen (5) through a pulse laser CCD camera (3), and carrying out binarization processing on the acquired image to completely reserve a light spot area;
step a2, extracting contour information of the spot image after binarization processing, recording the contour information as phi, and recording the contour edgeXAbscissa and ordinate of maximum point of coordinate values in the axial direction ((S))x 1 , y 1 ) As the starting point for curvature and curvature radius calculation;
step a3, calculating Φ st by the following equation in a counterclockwise direction from the start pointiCurvature at pointK i ：
Figure 824435DEST_PATH_IMAGE001
（1）
(x i , y i ) Is as followsiCoordinates of points;
step a4, analyzing curvature at each point phiK i And calculating the coordinates of the central point of the light spot as follows:
(i) curvature at each point of phiK i The method has no abrupt point, namely a light spot completely passes through a central hole of a pulse laser diaphragm (7) and falls on a pulse laser development screen (5), and the coordinates of the central point of the light spot are calculated according to the following formula:
Figure 736896DEST_PATH_IMAGE002
（2）
whereinSRepresenting the area of a light spot in the image of the pulsed laser CCD camera (3),nrepresents the number of discrete points of the light spot profile,x i 、y i represents the firstiThe horizontal and vertical coordinates of each discrete point;
Figure 311097DEST_PATH_IMAGE003
（3）
(ii) if curvatureK i Two catastrophe points exist, namely, only part of a light spot passes through a central hole of the pulse laser diaphragm (7), the rest part of the light spot is projected onto the pulse laser developing screen (5) through the pulse laser diaphragm (7), and then coordinates A (A) of the two curvature catastrophe points need to be extracted when the coordinates of the center point of the light spot are calculatedxx 1 , yy 1 ) And B (a), (B)xx 2 , yy 2 ) And calculating the curvature radius of two sections of circular arcs on the pulse laser developing screen (5), namely the curvature radius of the light spot and the curvature radius of the light spot projection:
Figure 322915DEST_PATH_IMAGE004
（4）
whereinK 1 ＞K 2 ，K 1 Which is the curvature of the spot itself,K 2 is the curvature of the projection of the light spot, wherein A: (xx 1 , yy 1 ) Is always maintained at B: (xx 2 , yy 2 ) On the right side of the frame,R 1 indicating the radius of curvature of the spot itself,R 2 a radius of curvature representing a projection of the spot;
to calculateO 1 (x 0 , y 0 ) The absolute coordinates in the imaging area of the pulsed laser CCD camera (3), i.e., in the Cartesian coordinate system, need to be first calculated A (A:)xx 1 , yy 1 ) And B (a), (B)xx 2 , yy 2 ) A midpoint C of (xx 3 , yy 3 ) Coordinates are as follows:
Figure 677673DEST_PATH_IMAGE005
（5）
by the central point of the light spotO 1 (x 0 , y 0 ) Establishing a sub-coordinate system for the origin, in which sub-coordinate system the origin is determined byO 1 C、O 1 The geometrical relationship between A and AC can be listed as follows:
Figure 3613DEST_PATH_IMAGE006
（6）
solving the above equation, if C: (xx 3 , yy 3 ) In the first quadrant of the sub-coordinate system, then (x 0 , y 0 ) Can be expressed as:
Figure 494637DEST_PATH_IMAGE007
（7a）
if C (C: (C))xx 3 , yy 3 ) In the second quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 677356DEST_PATH_IMAGE008
（7b）
if C (C: (C))xx 3 , yy 3 ) In the third quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 253831DEST_PATH_IMAGE009
（7c）
if C (C: (C))xx 3 , yy 3 ) In the fourth quadrant of the sub-coordinate system, thenx 0 , y 0 ) Can be expressed as:
Figure 383461DEST_PATH_IMAGE010
（7d）
step 2.3.3, according to the calculated coordinates of the geometric center point of the light spot, the pulse laser diaphragm (7) is finely adjusted through a fine adjustment mechanism on the pulse laser diaphragm (7) so that the center point of the light spot is enabled to be fine adjustedO 1 With the center of the imageOCoincidence to eccentricity of spot centerβSatisfies the following conditions:
Figure 728992DEST_PATH_IMAGE011
（8）
degree of eccentricityβThe calculation formula of (2) is as follows:
Figure 348192DEST_PATH_IMAGE012
（9）
wherein (A) and (B)x 0 , y 0 ) Representing the geometric center point coordinates of the light spot;
step 2.4, fixing the sliding rail (1) on an operation platform, installing a pulse laser (13), a first angle adjusting mechanism (9) and a second angle adjusting mechanism (10) on the operation platform, respectively installing a first reflecting mirror (11) and a second reflecting mirror (12) on the first angle adjusting mechanism (9) and the second angle adjusting mechanism (10), wherein the first reflecting mirror (11) and the second reflecting mirror (12) are oppositely arranged, the inclination angles of the first reflecting mirror (11) and the second reflecting mirror (12) are respectively 45 degrees and 135 degrees, and the connecting line between the second reflecting mirror (12) and the pulse laser developing screen (5) is parallel to the connecting line between the first reflecting mirror (11) and the pulse laser (13);
step 2.5, starting a pulse laser (13), manually adjusting a first reflecting mirror (11) and a second reflecting mirror (12) to enable the pulse laser to completely pass through a pulse laser diaphragm (7), and forming a complete light spot on a pulse laser developing screen (5);
step 2.6, adjusting the pulse laser by adjusting the first reflector (11) and the second reflector (12) to enable the pulse laser to be coaxial with the pulse laser CCD camera (3), and specifically comprises the following steps:
step 2.6.1, defining the first angle adjusting mechanism (9) and the second angle adjusting mechanism (10)YShaft rotating electric machine (904) andXthe positive and negative rotation of the shaft rotating motor (908) is specifically as follows: slave motorViewed from the shaft end direction, the first angle adjusting mechanism (9) and the second angle adjusting mechanism (10)YShaft rotating electric machine (904) andXthe clockwise rotation of the shaft rotating motor (908) is called forward rotation, the anticlockwise rotation is called reverse rotation, the angle is positive when the shaft rotating motor rotates forwards, and the angle is negative when the shaft rotating motor rotates reversely;
step 2.6.2, acquiring a light spot image on a pulse laser developing screen (5) through a pulse laser CCD camera (3), carrying out binarization processing, extracting contour information after binarization processing, and calculating the roundness coefficient of the light spot by using a formula (10)δ；
Figure 349646DEST_PATH_IMAGE013
（10）
WhereinSRepresenting the area of a light spot in the image of the pulsed laser CCD camera (3),crepresenting the perimeter of a light spot in an image of a pulsed laser CCD camera (3);
Figure 79705DEST_PATH_IMAGE014
（11）
Figure 545321DEST_PATH_IMAGE015
（12）
step 2.6.3, judging the roundness coefficient of the current light spotδIf, ifδ≤δ 0 Then, the center coordinates of the current light spot are calculated by using the formula (2)O 1 (x 0 , y 0 ) If, ifδ＞δ 0 Then, the center coordinates of the current spot are calculated by using the formula (7 a), (7 b), (7 c) or (7 d)O 1 (x 0 , y 0 )；
Step 2.6.4, calculating the eccentricity of the current light spot by using the formula (9), if the eccentricity is not calculated, calculating the eccentricity of the current light spotβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Then the position of the light spot is adjusted；
Step 2.6.5, adjust the current light spot andXthe deviation of the shaft comprises the following specific steps:
b1, recording the current spot centerO 1 In the quadrant of the Cartesian coordinate system, and reading the current eccentricityβ；
b2, defining the motor rotation direction coefficientM、NWhereinMFor indicating an angle adjusting mechanism (9)XShaft rotating electric machine (908) andYa rotation direction coefficient of the shaft rotating motor (904),Nfor indicating a second angle adjusting mechanism (10)XShaft rotating electric machine (908) andYa rotation direction coefficient of the shaft rotating motor (904),M、Nis selected from 1 and-1, 1 and-1 respectively represent forward rotation and reverse rotation, if the central coordinate of the light spotO 1 In the first or second quadrant, the definition is initializedM=1、N=1, if the center coordinates of the light spotO 1 In the third or fourth quadrant, the definition is initializedM=1、N=1；
b3, calculating the current pulse laser beam andXangle of horizontal plane of axisθ x ：
Figure 273106DEST_PATH_IMAGE016
（13）
Whereinl 2 Represents the horizontal distance between the second reflecting mirror (12) and the pulse laser developing screen (5),y 0 is the ordinate of the light spot center;
in a second angle adjusting mechanism (10)XStep rotation angle Delta of shaft rotation motor 908θ x2 Comprises the following steps:
Figure 558594DEST_PATH_IMAGE017
（14）
in a first angle adjusting mechanism (9)XStep rotation angle Delta of shaft rotation motor 908θ x1 Comprises the following steps:
Figure 92343DEST_PATH_IMAGE018
（15）
whereinl 1 Represents the distance between the first reflector (11) and the second reflector (12);
b4 recording the current eccentricity of the light spot asβ 1 Defining an angle adjusting mechanism (9)XStep rotation angle of shaft rotation motor (908)MΔθ x1 In a second angle adjusting mechanism (10)XStep rotation angle of shaft rotation motor (908)NΔθ x2 ；
b5 in the first angle adjusting mechanism (9)XRotation of shaft rotating electric machine (908)MΔθ x1 In the primary and secondary angle adjusting mechanism (10)XThe shaft rotating motor (908) rotates in successive steps, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
b6, judging the current eccentricityβWhether less than the eccentricity recorded in step b4β 1 If, ifβ≥β 1 In a first angle adjusting mechanism (9)XThe rotating direction of the shaft rotating motor (908) is wrong, so thatM= -1, repeat step b5 untilβ＜β 1 (ii) a If it isβ＜β 1 In a first angle adjusting mechanism (9)XThe shaft rotating motor (908) has correct rotating direction and enters the next step;
b7, judging the current eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Then, the adjustment is continued, in a first angle adjusting mechanism (9)XRotation of shaft rotating electric machine (908)MΔθ x1 In the primary and secondary angle adjusting mechanism (10)XThe shaft rotating motor (908) is continuously steppedRotation, step by stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
b8, judging the current eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Entering the next step;
b9, if the current spot centerO 1 The quadrant comparison step b1 is changed, and the process is stoppedXAdjustment of the axis deviation if the current spot centerO 1 If the quadrant is not changed compared with the step b1, returning to the step b 7;
step 2.6.6, judging the current eccentricityβIf, ifβ≤β 0 If so, the adjustment is finished; if it isβ＞β 0 Then adjust the current spot andYthe deviation of the shaft comprises the following specific steps:
c1, recording the current spot centerO 1 In the quadrant of the Cartesian coordinate system, and reading the current eccentricityβ；
c2, if the center coordinate of the current light spotO 1 In the first or fourth quadrant, the definition is initializedM=1、N=1, if the center coordinates of the light spotO 1 In the second or third quadrant, the definition is initializedM=1、N=-1；
c3, calculating the current pulse laser beam andYangle of horizontal plane of axisθ y ：
Figure 740362DEST_PATH_IMAGE019
（16）
x 0 The abscissa is the center of the light spot;
in a second angle adjusting mechanism (10)YStep rotation angle Delta of shaft rotation motor 904θ y2 Comprises the following steps:
Figure 763682DEST_PATH_IMAGE020
（17）
in a first angle adjusting mechanism (9)YStep rotation angle Delta of shaft rotation motor 904θ y1 ：
Figure 67624DEST_PATH_IMAGE021
（18）
c4, recording the current eccentricity of the light spotβ 2 The system defines an angle adjusting mechanism (9)YStep rotation angle of shaft rotation motor (904)MΔθ y1 In a second angle adjusting mechanism (10)YStep rotation angle of shaft rotation motor (904)NΔθ y2 ；
c5 in the first angle adjusting mechanism (9)YThe shaft rotating motor (904) rotatesMΔθ x1 In the primary and secondary angle adjusting mechanism (10)YThe shaft rotating motor (904) rotates in successive steps, each stepNΔθ x2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
c6, judging eccentricityβWhether less than the eccentricity recorded in step c4β 2 If, ifβ≥β 2 In a first angle adjusting mechanism (9)YThe rotating direction of the shaft rotating motor (904) is wrong, so thatM= -1, re-rotation ifβ＜β 1 In a first angle adjusting mechanism (9)YThe shaft rotating motor (904) has correct rotating direction and enters the next step;
c7, judging eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Then, the adjustment is continued, in a first angle adjusting mechanism (9)YThe shaft rotating motor (904) rotatesMΔθ y1 In the primary and secondary angle adjusting mechanism (10)YThe shaft rotating motor (904) rotates in successive steps, each stepNΔθ y2 Rear uniform update eccentricityβUp to eccentricityβNo longer decreases;
c8, judging eccentricityβWhether or not the stop condition is satisfied, ifβ≤β 0 Then the adjustment is finished, ifβ＞β 0 Entering the next step;
c9, if the current spot centerO 1 The quadrant comparison step c1 is changed, and the operation is stoppedYAdjustment of the axis deviation if the current spot centerO 1 If the quadrant is not changed compared with the step c1, returning to the step c 7;
step 2.6.7, determining the current eccentricityβIf, ifβ＞β 0 Then go back to step c7 ifβ≤β 0 If so, the adjustment is finished;
step 3, repeating the step 2, and calibrating the continuous laser side light path;
step 4, sequentially removing the pulse laser CCD camera (3), the continuous laser CCD camera (4) and the camera coaxial mounting block (2), mounting a sample clamp at the position where the camera coaxial mounting block (2) is located, and clamping a metal composite plate on the sample clamp, wherein the base layer of the metal composite plate faces the pulse laser, and the composite layer of the metal composite plate faces the continuous laser of the interferometer;
and 5, acquiring laser ultrasonic signals of the metal composite plate, and respectively calculating the thicknesses of the composite layer and the base layer.
5. The method of claim 4 for measuring the thickness of a laser ultrasonic metal composite slab with self-adjusting optical path alignment, wherein the method comprises the following steps: the step 5 of obtaining the laser ultrasonic signal of the metal composite plate and respectively calculating the thicknesses of the composite layer and the base layer comprises the following specific steps:
step 5.1, a pulse laser (13) is started, the pulse laser excites ultrasonic waves at the base layer of the metal composite plate, due to the difference of acoustic impedances of the composite layer and the base layer, the ultrasonic waves are transmitted and reflected at the interface of the base layer and the composite layer at the same time when being transmitted to the interface of the base layer and the composite layer, and then the ultrasonic waves are transmitted and reflected by the interface of the base layer and the composite layerAn optical interferometer (14) receives ultrasonic echo signals in the metal composite plate in a multi-layer mode, marks direct longitudinal waves I, interface primary reflected waves II and top surface primary reflected waves III respectively, and extracts the occurrence time of the direct longitudinal waves I, the interface primary reflected waves II and the top surface primary reflected waves III in the signalst Ⅰ 、t Ⅱ 、t Ⅲ From this, the thickness of the multilayer is calculated:
Figure 873906DEST_PATH_IMAGE022
（19）
in the above formula, the first and second carbon atoms are,h 1 the thickness of the multi-layer is the thickness of the multi-layer,v 1 the propagation speed of the direct longitudinal wave in the multiple layers;
step 5.2, the thickness of the metal composite plate is formed by the thickness of the base layer and the thickness of the compound layer, and the following equation can be listed according to the propagation time of the ultrasonic waves in the base layer and the compound layer:
Figure 782956DEST_PATH_IMAGE023
（20）
in the above formula, the first and second carbon atoms are,h 2 is the thickness of the base layer,v 2 the propagation speed of the ultrasonic longitudinal wave in the base layer is shown;
the thickness of the base layer of the composite panel can be derived from equation (20):
Figure 914860DEST_PATH_IMAGE024
（21）。
6. the method of claim 4, wherein the method comprises the steps of: up to eccentricity of said steps b5 and b7βNo longer decreases: in particular to a second angle adjusting mechanism (10)XThe shaft rotating motor (908) rotates in a continuous stepping manner and has eccentricityβIn the process of continuously reducing, eccentricity occursβIn the case of increasing, the eccentricity at the turning point is determinedβThe point at which the reduction is no longer reduced, then in the second angle adjustment mechanism (10)XThe shaft rotating motor (908) rotates in reverse to eccentricityβA corner point; up to eccentricity in said c5 and c7βNo longer decreases: in particular to a second angle adjusting mechanism (10)YThe shaft rotating motor (904) rotates in a continuous stepping manner and has eccentricityβIn the process of continuously reducing, eccentricity occursβIn the case of increasing, the eccentricity at the turning point is determinedβThe point at which the reduction is no longer reduced, then in the second angle adjustment mechanism (10)YThe shaft rotating motor (904) rotates in reverse to eccentricityβAt the point of inflection.
CN202210741145.1A 2022-06-28 2022-06-28 Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method Active CN114812457B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210741145.1A CN114812457B (en) 2022-06-28 2022-06-28 Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210741145.1A CN114812457B (en) 2022-06-28 2022-06-28 Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method

Publications (2)

Publication Number Publication Date
CN114812457A true CN114812457A (en) 2022-07-29
CN114812457B CN114812457B (en) 2022-09-23

Family

ID=82522961

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210741145.1A Active CN114812457B (en) 2022-06-28 2022-06-28 Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method

Country Status (1)

Country Link
CN (1) CN114812457B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117073550A (en) * 2023-10-12 2023-11-17 太原理工大学 Non-contact metal pipe wall thickness measuring device

Citations (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0390478A1 (en) * 1989-03-31 1990-10-03 Seiko Instruments Inc. X-ray apparatus for measuring film thickness
JPH09113228A (en) * 1995-10-13 1997-05-02 Asahi Chem Ind Co Ltd Film thickness meter
CN1363820A (en) * 2002-02-05 2002-08-14 北京大学 Short-pulse laser and ultrasonic method and equipment for presisely measuring thickness
WO2003019114A1 (en) * 2001-08-30 2003-03-06 Centre De Recherches Metallurgiques, A.S.B.L. Method and device for measuring distances on bright metal strips
US20030144650A1 (en) * 2002-01-29 2003-07-31 Smith Robert F. Integrated wavefront-directed topography-controlled photoablation
CN1641313A (en) * 2005-01-04 2005-07-20 华南理工大学 POP can opening impression residual thickness measuring device and its measuring method
CN101210806A (en) * 2007-12-20 2008-07-02 哈尔滨工业大学 Laser emission axis and mechanical base level coaxiality measuring method based on secondary light source
CN101592787A (en) * 2008-05-28 2009-12-02 北京中视中科光电技术有限公司 A kind of apparatus and method that are used for the light path adjusting
US20100053617A1 (en) * 2008-06-27 2010-03-04 Nec Lcd Technologies, Ltd. Alignment marker, display device using the same, and fabrication method thereof
CN102353330A (en) * 2011-08-30 2012-02-15 东莞市盟拓光电科技有限公司 Method for determining solder paste datum plane in three-dimensional solder paste thickness test
CN102506781A (en) * 2011-11-17 2012-06-20 江苏大学 Laser ultrasonic thickness measuring method and laser ultrasonic thickness measuring device capable of being used for field detection
CN102679892A (en) * 2012-05-11 2012-09-19 华中科技大学 Single-lens laser trigonometry thickness measuring instrument
CN102967281A (en) * 2012-11-29 2013-03-13 中国航空综合技术研究所 System for measuring longitudinal wave thickness of pulse laser
CN103363911A (en) * 2013-04-25 2013-10-23 谢逢春 Laser thickness gauge taking laser as light source
CN204924188U (en) * 2015-05-27 2015-12-30 郑州宏拓超硬材料制品有限公司 Thin slice thickness measurement with laser system
CN107421473A (en) * 2017-05-26 2017-12-01 南京理工大学 The two beam laser coaxial degree detection methods based on image procossing
CN109827511A (en) * 2018-12-12 2019-05-31 常州工学院 Thickness measurement with laser is to penetrating hot spot automatic detection device and method
CN110672047A (en) * 2019-10-16 2020-01-10 江苏省特种设备安全监督检验研究院 Laser ultrasonic measurement method for thickness of high-temperature metal material
CN112229338A (en) * 2020-11-27 2021-01-15 中国计量科学研究院 Double-spectrum confocal thickness measuring method without standard sheet zero alignment
CN212409631U (en) * 2020-08-14 2021-01-26 深圳市兴华炜科技有限公司 High-precision thickness measuring device for large-size object
CN112362732A (en) * 2020-10-21 2021-02-12 南京理工大学 Free-form surface defect detection method and system based on laser ultrasonic elliptical imaging
CN113008803A (en) * 2021-02-01 2021-06-22 太原理工大学 Laser ultrasonic nondestructive online detection method and device for surface cracks of bar

Patent Citations (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0390478A1 (en) * 1989-03-31 1990-10-03 Seiko Instruments Inc. X-ray apparatus for measuring film thickness
JPH09113228A (en) * 1995-10-13 1997-05-02 Asahi Chem Ind Co Ltd Film thickness meter
WO2003019114A1 (en) * 2001-08-30 2003-03-06 Centre De Recherches Metallurgiques, A.S.B.L. Method and device for measuring distances on bright metal strips
US20030144650A1 (en) * 2002-01-29 2003-07-31 Smith Robert F. Integrated wavefront-directed topography-controlled photoablation
CN1363820A (en) * 2002-02-05 2002-08-14 北京大学 Short-pulse laser and ultrasonic method and equipment for presisely measuring thickness
CN1641313A (en) * 2005-01-04 2005-07-20 华南理工大学 POP can opening impression residual thickness measuring device and its measuring method
CN101210806A (en) * 2007-12-20 2008-07-02 哈尔滨工业大学 Laser emission axis and mechanical base level coaxiality measuring method based on secondary light source
CN101592787A (en) * 2008-05-28 2009-12-02 北京中视中科光电技术有限公司 A kind of apparatus and method that are used for the light path adjusting
US20100053617A1 (en) * 2008-06-27 2010-03-04 Nec Lcd Technologies, Ltd. Alignment marker, display device using the same, and fabrication method thereof
CN102353330A (en) * 2011-08-30 2012-02-15 东莞市盟拓光电科技有限公司 Method for determining solder paste datum plane in three-dimensional solder paste thickness test
CN102506781A (en) * 2011-11-17 2012-06-20 江苏大学 Laser ultrasonic thickness measuring method and laser ultrasonic thickness measuring device capable of being used for field detection
CN102679892A (en) * 2012-05-11 2012-09-19 华中科技大学 Single-lens laser trigonometry thickness measuring instrument
CN102967281A (en) * 2012-11-29 2013-03-13 中国航空综合技术研究所 System for measuring longitudinal wave thickness of pulse laser
CN103363911A (en) * 2013-04-25 2013-10-23 谢逢春 Laser thickness gauge taking laser as light source
CN204924188U (en) * 2015-05-27 2015-12-30 郑州宏拓超硬材料制品有限公司 Thin slice thickness measurement with laser system
CN107421473A (en) * 2017-05-26 2017-12-01 南京理工大学 The two beam laser coaxial degree detection methods based on image procossing
CN109827511A (en) * 2018-12-12 2019-05-31 常州工学院 Thickness measurement with laser is to penetrating hot spot automatic detection device and method
CN110672047A (en) * 2019-10-16 2020-01-10 江苏省特种设备安全监督检验研究院 Laser ultrasonic measurement method for thickness of high-temperature metal material
CN212409631U (en) * 2020-08-14 2021-01-26 深圳市兴华炜科技有限公司 High-precision thickness measuring device for large-size object
CN112362732A (en) * 2020-10-21 2021-02-12 南京理工大学 Free-form surface defect detection method and system based on laser ultrasonic elliptical imaging
CN112229338A (en) * 2020-11-27 2021-01-15 中国计量科学研究院 Double-spectrum confocal thickness measuring method without standard sheet zero alignment
CN113008803A (en) * 2021-02-01 2021-06-22 太原理工大学 Laser ultrasonic nondestructive online detection method and device for surface cracks of bar

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
K.-J.BOEHM等: "Assembly and metrology of NIF target subassemblies using robotic systems", 《HIGH POWER LASER SCIENCE AND ENGINEERING》 *
宋海峰 等: "双激光位移传感器测厚实验装置的研制", 《太赫兹科学与电子信息学报》 *
汪琛 等: "单镜头激光三角法薄板厚度测量研究", 《激光技术》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117073550A (en) * 2023-10-12 2023-11-17 太原理工大学 Non-contact metal pipe wall thickness measuring device
CN117073550B (en) * 2023-10-12 2023-12-15 太原理工大学 Non-contact metal pipe wall thickness measuring device

Also Published As

Publication number Publication date
CN114812457B (en) 2022-09-23

Similar Documents

Publication Publication Date Title
CA2626026C (en) Ultrasonic testing system and ultrasonic testing technique for pipe member
CN114812457B (en) Light path alignment self-adjusting laser ultrasonic metal composite plate thickness measuring device and method
CN108956776A (en) The ultrasonic phased array detection method and system of U rib full penetration fillet welding seam defect
WO2020250378A1 (en) Ultrasound flaw detection method, ultrasound flaw detection device, manufacturing equipment line for steel material, manufacturing method for steel material, and quality assurance method for steel material
CN110988139A (en) Phased array ultrasonic detection method for welding buoy base plate and sampan
CN111174894B (en) Laser ultrasonic transverse wave sound velocity measurement method
CN114674928A (en) Method for suppressing blind area in ultrasonic TOFD (time of flight diffraction) detection of thin plate structure based on second-order mode wave
CN113866279B (en) Ultrasonic phased array detection method for curved surface double-shaft-shoulder friction stir welding seam
CN113884035A (en) Ultrasonic detection system and detection method for thick-wall pipe
CN1715893A (en) Fault positioning method in complicate welding structure
JP2009058238A (en) Method and device for defect inspection
KR101942792B1 (en) Steel material quality evaluation method and quality evaluation device
CN111060044B (en) Method for measuring thickness of welding type target by adopting water immersion type C-scan equipment
JPH05261564A (en) Manufacture of electric resistance welded tube
WO2022104907A1 (en) Micro-space three-dimensional morphology measurement apparatus
Wüst et al. 3‐D Scanning Acoustic Microscope for Investigation of Curved‐Structured Smart Material Compounds
JP3557553B2 (en) Ultrasonic testing method for welded joints
JP2943567B2 (en) Pipe shape inspection device
CN110988116A (en) Method and device for distinguishing defect signals of inner wall and outer wall of water immersion ultrasonic detection pipe
CN111413412A (en) Method for measuring refraction angle of ultrasonic probe
JP5641435B2 (en) Ultrasonic oblique angle flaw detection method and ultrasonic oblique angle flaw detector
CN114002323B (en) Imaging detection method and system for interface debonding of solid rocket engine II
CN217466810U (en) Detection mechanism of gear
CN114487102B (en) Ultrasonic detection method for weld joint phased array with residual height
CN113418991A (en) Reference block and method for determining incident point of circumferential defect detection of pipe fitting

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant