A non-contact length measuring device based on two-end interferometry

Abstract

The application discloses a kind of non-contact length measuring devices based on double-end interferometry, belong to laser measuring instrument technical field, comprising: mounting plate, mounting plate upper surface is fixedly installed with frequency stabilization laser, frequency stabilization laser upper surface is fixedly installed with Y-shaped frame, Y-shaped frame is fixedly installed with the laser emitter of frequency stabilization laser in, and Y-shaped frame one end is fixedly installed with converging lens, mounting plate upper surface one end is fixedly installed with first collimating lens and mirror, so that the measurement light emitted by laser emitter will be formed into parallel light beam in turn through converging lens and first collimating lens.This application is measured by converging lens, light splitting mechanism, mirror, first collimating lens and second collimating lens design, so that it uses interferometry to measure the length of end degree length standard, without direct contact with the measured piece, avoid the scratch that traditional measurement mode can cause to the surface of measured piece, reduce maintenance cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser measuring instruments, in particular to a non-contact length measuring device based on double-end interference method. BACKGROUND

[0002] End measurement technology is an important part of length measurement. End measurement has many forms in length measurement, such as gauge block length measurement. Traditional lapping end measurement cannot achieve higher precision measurement due to the influence of lapping layer thickness and the technical level of lapping personnel. With the development of technology, the measurement precision required by such end measurement is getting higher and higher. From lapping measurement to double-end measurement without lapping. It can realize end measurement without lapping. Double-end interference measurement technology can directly reflect the interference light on the two surfaces of the measured object to form interference fringes, and finally realize end measurement without lapping. Double-end interference is a new type of non-lapping and non-contact measurement method for measuring the length of gauge block.

[0003] However, in the field of modern industrial manufacturing and precision measurement, length measurement as a basic and key technology directly affects product quality and production efficiency. With the rapid development of science and technology, traditional length measurement methods are difficult to meet the demand for high-precision measurement and non-contact measurement. Therefore, a non-contact length measuring device based on double-end interference method is proposed. SUMMARY

[0004] The purpose of the present application is to provide a non-contact length measuring device based on double-end interference method to solve the problem that traditional length measurement methods gradually fail to meet the demand for high-precision and non-contact measurement.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A non-contact length measuring device based on double-end interference method, comprising: a mounting plate, a frequency stabilized laser is fixedly installed on the upper surface of the mounting plate, a Y-shaped frame is fixedly installed on the upper surface of the frequency stabilized laser, a laser emitter of the frequency stabilized laser is fixedly installed in the Y-shaped frame, a converging lens is fixedly installed at one end of the Y-shaped frame, the converging lens is flush with the laser emitter, a first collimating lens and a mirror are fixedly installed at one end of the upper surface of the mounting plate, and the first collimating lens and the mirror are also flush with the converging lens, and the mirror is inclined;

[0007] Wherein, the measurement light emitted by the laser emitter is sequentially formed into a parallel light beam by the converging lens and the first collimating lens, and then is reflected by the mirror to the spectrometer, which is fixedly installed at the center of the upper surface of the mounting plate, and is provided with three groups of spectrometers (2) arranged in a triangular shape, and the spectrometers on both sides are symmetrically arranged, and a workbench is fixedly installed between the three groups of spectrometers, a clamping mechanism is fixedly installed on the upper surface of the workbench, and the clamping mechanism can clamp the measured member.

[0008] Wherein, the measurement light first incident to the spectrometer through the mirror is divided into two paths, and the measurement light divided into two paths is incident to the other two groups of spectrometers at the lower part, and the two spectrometers at the lower part divide the measurement light beam into two paths again, one of which is incident to the reference mirror, and the other is incident to the outer surface of the measured member clamped by the clamping mechanism, and the reference mirror returns the light to the interference with the reflected light from the surface of the measured member and the light beam reflected by the spectrometer on the other side, forming interference fringes, and the interference fringes on both sides are collected by the camera again through the second collimating lens, which is fixedly installed at both ends of the upper surface of the mounting plate and flush with the camera, and the reference mirror is connected to the PZT phase shifter through the frame to realize phase-shifting interferometry.

[0009] Wherein, the PZT phase shifter is fixedly installed in the connecting frame, and the frame is fixedly connected to the connecting frame, the connecting arm is rotatably installed on the lower surface of the connecting frame, the other end of the connecting arm is rotatably installed with the fastening plate, the fastening plate is fixedly installed at both ends of the upper surface of the mounting plate, and the camera is fixedly installed at one end of the turnover plate, the turnover plate is rotatably installed in the U-shaped frame, and the U-shaped frame is also fixedly installed at both ends of the upper surface of the mounting plate.

[0010] Preferably, the fastening plate rotatably connected with the connecting arm and one end of the connecting frame are both threadedly installed with a first butterfly bolt, so that the first butterfly bolt can be screwed into the end of the connecting arm to achieve the locking of rotation, and through the rotatable connection, the rotatably installed connecting arm and connecting frame can be angularly flipped.

[0011] Preferably, a second butterfly bolt is rotatably installed at one end of the U-shaped frame, the other part of the second butterfly bolt can be threadedly screwed through the U-shaped frame and threadedly pressed at one end of the turnover plate to achieve the locking of rotation, and through the flipping action, the camera fixedly installed at one end can be angularly flipped.

[0012] Preferably, the three sets of light splitting mechanisms comprise three sets of connecting plates, which are fixedly installed on the upper surface of the mounting plate and arranged in a triangular shape, and the outer surfaces of the three sets of connecting plates are slidably sleeved with connecting blocks, and the upper surfaces of the three sets of connecting blocks are fixedly installed with first, second and third light splitters, so that the first, second and third light splitters are arranged in a triangular shape.

[0013] Preferably, the first light splitter splits the reflected light into two beams, and the two beams after the first splitting are incident into the second and third light splitters, respectively, so that the two light splitters split the received light into two beams, respectively, so that a total of four beams are generated, and then the two beams on both sides are split to the reference mirror and the measured object, the light reflected by the reference mirror is reflected back along the original path, and the light reflected by the measured object is also reflected back from the surface of the measured object, so that the reflected light of the reference mirror and the reflected light of the measured object and the light reflected by the other light splitter interfere with each other to form interference fringes, and the interference fringes are collected by the camera after passing through the second collimating lens.

[0014] Preferably, a threaded rod is rotatably installed in each of the three sets of connecting plates, the threaded rod passes through the connecting block in a threaded manner, and both ends of the threaded rod also rotatably pass out of the connecting plate and are fixedly installed with a hand wheel at the end portion, one end of the connecting block fixedly installed on the outer surface of the threaded rod is fixedly installed with a plug, one end of the plug is fixedly installed with a threaded column, the outer surface of the plug is slidably inserted with a locking block, and the outer surface of the threaded column is threadedly installed with a pressing column, so that the pressing column can be screwed onto the outer surface of the threaded column to push the locking block inward on the outer surface of the plug, and the locking block inwardly sliding can be in contact with one end of the connecting block and one end of the connecting plate, so as to realize the locking of the sliding of the connecting block.

[0015] Preferably, the clamping mechanism comprises a first motor fixedly installed on the upper surface of the workbench, a connecting disc fixedly installed on the outer surface of the output shaft of the first motor, an installation frame fixedly installed on the upper surface of the connecting disc, and a clamping arm rotatably installed on the outer surface of both ends of the installation frame, and a half tooth fixedly installed on the inner surface of each of the two clamping arms, and the two half teeth are engaged with each other, so that the two clamping arms can be synchronously driven to turn outward or clamped to the center.

[0016] Preferably, a second motor is fixedly installed in the installation frame, and the output shaft of the second motor rotatably passes through the installation frame and is fixedly connected with one of the clamping arms.

[0017] Preferably, the first motor is externally fixed with a suspension frame, the suspension frame is internally fixed with a laser ranging sensor, the laser ranging sensor is flush with a rotating ring, the rotating ring is fixed on the lower surface of the connecting disc, the outer surface of the rotating ring is in the shape of an ellipse from narrow to wide, when the rotating ring is rotated by the first motor, the distance between the rotating ring and the laser ranging sensor changes constantly, the laser ranging sensor continuously detects the distance between the rotating ring and the laser ranging sensor and transmits data to the controller, the controller is internally provided with a corresponding relationship model of the distance and the angle, according to the received different distance data, the distance change is converted into the angle information of the rotating ring through algorithm conversion, so that the measurement and feedback of the rotating angle are realized, and the control output end of the controller is electrically connected with the electric control end of the first motor.

[0018] Preferably, the model of the laser ranging sensor and the controller is AMS307i120 and S7-1500 respectively.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. Through the design of the frequency stabilized laser, laser emitter, converging lens, first collimating lens, mirror, reference mirror, second collimating lens, PZT phase shifter, camera, light splitting mechanism and clamping mechanism, when in use, the staff can clamp the measured object in the clamping mechanism, then start the frequency stabilized laser to let the laser emitter emit measuring light to the converging lens first, the measuring light converges through the converging lens, then forms a parallel light beam through the first collimating lens, the light beam is incident on the center of the symmetrically arranged triangular light splitting mechanism on the upper surface of the installation plate after changing direction by the inclined mirror, in the light splitting mechanism, the measuring light is first split into two paths by the first group of light splitting mechanism, the two paths of light are respectively incident on the other two groups of light splitting mechanism, in the other two groups of light splitting mechanism, the measuring light is again split into two paths, finally forming four paths of light, among them, two paths of light are respectively incident on the reference mirror, and the other two paths of light are incident on the outer surface of the measured object clamped by the clamping mechanism, at the same time, the light incident on the reference mirror returns to the original path by the reflection performance, and the light incident on the measured object is also reflected from the surface of the measured object, so that the reflected light of the reference mirror and the reflected light of the surface of the measured object, and the light reflected by the other side of the light splitting mechanism interfere with each other, thereby forming interference fringes, which contain the relevant information of the length of the measured object, and the interference fringes are incident into the second collimating lens, and the second collimating lens collimates the interference fringes to ensure that they are clear and stable, then they are collected by the camera, and the camera converts the collected interference fringe image information into electrical or digital signals and transmits them to the subsequent data processing system for length analysis, that is, the non-contact measurement function is realized, and in this process, the reference mirror is connected with the PZT phase shifter through the frame, the PZT phase shifter can realize phase shifting interference measurement, by applying different voltage signals to the PZT phase shifter, the micro displacement of the reference mirror can be accurately controlled, the phase of the reflected light is changed, the interference fringe change data under different phases is combined with the pre-established mathematical model and algorithm, so that the length of the measured object can be more accurately calculated, and the measurement accuracy and reliability are effectively improved, in addition, the connecting frame is rotatably connected with the fastening plate through the connecting arm, and the first butterfly bolt is installed at the connecting place, when it is necessary to adjust the angle of the reference mirror, loosen the first butterfly bolt, rotate the connecting arm and the connecting frame to the appropriate angle, then tighten the first butterfly bolt to lock, so as to ensure that the reference mirror remains stable during the measurement process, similarly, the angle of the camera can be flexibly adjusted and fixed by connecting the V-shaped frame and the turnover plate through the second butterfly bolt, so as to ensure that the camera can clearly and accurately collect the interference fringes.

[0021] 2、Through the design of the first beam splitter, the second beam splitter and the third beam splitter, the connecting block, the threaded rod, the threaded column, the locking block and the pressing column, the measurement light reflected by the reflector will be incident on the first beam splitter arranged in a triangle on the mounting plate at a specific angle, and the first beam splitter is fixed on the upper surface of the connecting block and will accurately divide the incident measurement light into two paths by its optical properties, completing the initial light splitting. This process uses the reflection and transmission principles of the first beam splitter to separate the light beam according to the preset ratio, providing a basic light path branch for subsequent measurement. The two beams after the initial light splitting will be respectively incident on the second beam splitter and the third beam splitter, which are also installed on the corresponding connecting blocks. The received light beams are again divided into two beams, resulting in a total of four beams. Among them, the two beams on the two sides are respectively incident on the reference mirror and the measured object. The light reflected by the reference mirror and the surface of the measured object interferes with the light reflected by the light splitter on the other side, forming interference fringes carrying the length information of the measured object, which are collected by the camera for measurement and calculation. In the structural design of the light splitting mechanism, the connecting block installed on the outer surface of the connecting plate slide and the threaded rod constitute a flexible adjustment system. The staff can rotate the hand wheel to drive the threaded rod to rotate. Since the threaded rod is threaded with the connecting block, the connecting block will slide along the outer surface of the connecting plate, thereby realizing the accurate adjustment of the positions of the first beam splitter, the second beam splitter and the third beam splitter. They can flexibly change the positions of the beam splitters according to different measurement requirements, different sizes of measured objects and light path calibration requirements, to ensure that the measurement light can be accurately incident and split. When the positions of the beam splitters are adjusted in place, the pressing column is tightened on the threaded column, which pushes the locking block to slide inward on the outer surface of the plug block until the locking block simultaneously touches the connecting block and the connecting plate, firmly locking the connecting block. This avoids the displacement of the beam splitter positions caused by factors such as vibration and collision during measurement, ensuring the stability of the light splitting path and the accuracy of the measurement.

[0022] 3、By the design of the first motor, the second motor, the clamping arm, the half tooth, the laser ranging sensor and the rotating ring, when the measured piece is placed, the second motor can be started to drive a group of clamping arms fixedly connected therewith to rotate, and because the half teeth on the inner sides of the two groups of clamping arms are meshed with each other, the rotating clamping arm can drive the other group of clamping arms to move synchronously, so that the two groups of clamping arms are clamped towards the center, thereby stably clamping the measured piece in the middle, and through the structure design that the two groups of half teeth are meshed with each other, the synchronism of the clamping arm action is ensured, a uniform clamping force can be provided, it is ensured that measured pieces of different shapes and sizes can be stably fixed, measurement errors caused by unstable clamping are reduced, and this symmetrical synchronous clamping method can not only adapt to measured pieces of different shapes and sizes, but also provide uniform and stable clamping force, avoid the position deviation of the measured piece caused by uneven force, effectively reduce the measurement error, significantly improve the reliability of the measurement result, and after the clamping of the measured piece is completed, the first motor can be started to drive the connecting disc to rotate, the connecting disc can drive the mounting frame fixedly installed on the upper surface and the clamped measured piece to rotate together, the rotating ring fixedly installed on the lower surface of the connecting disc is also driven to rotate, and the outer surface of the rotating ring is in a special elliptical shape and opposite to the laser ranging sensor in the suspended frame, so that during the rotation of the connecting disc, the distance between the rotating ring and the laser ranging sensor changes constantly along with the change of the elliptical contour of the rotating ring, and in this process, the laser ranging sensor detects the distance in real time and transmits the data to the controller, the controller has a pre-set corresponding relationship model of the distance and the angle, the received distance data is converted into the angle information of the rotation of the rotating ring through an algorithm, at the same time, the controller is connected with the electric control end of the first motor to form a closed-loop control system, when the controller judges that there is a deviation in the rotation angle according to the angle information, the running state of the first motor is adjusted in time to ensure that the measured piece is driven to rotate to an accurate angle, providing an accurate positioning basis for subsequent length measurement based on the double-end interference method, thereby ensuring the accuracy and effectiveness of the whole measurement process. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a whole structure schematic diagram of the present application;

[0024] Figure 2 It is a structure schematic diagram of the first collimating lens and the second collimating lens of the present application;

[0025] Figure 3 It is a whole overhead structure schematic diagram of the present application;

[0026] Figure 4 It is a structure schematic diagram of the light splitting mechanism of the present application;

[0027] Figure 5 It is a structure schematic diagram of the clamping and grabbing mechanism of the present application;

[0028] Figure 6Structure diagram of the laser ranging sensor and the rotary joint in the application;

[0029] Figure 7 Structure diagram of the measurement light path reflection and branching in the application.

[0030] In the figure: 1, mounting plate; 101, frequency stabilized laser; 102, laser emitter; 103, Y-shaped frame; 104, converging lens; 105, first collimating lens; 106, mirror; 107, workbench; 108, V-shaped frame; 109, flip plate; 110, fastening plate; 111, connecting arm; 112, connecting frame; 113, frame; 114, reference mirror; 115, first butterfly bolt; 116, second collimating lens; 117, second butterfly bolt; 118, PZT phase shifter; 119, camera; 2, light splitting mechanism; 201, connecting plate; 202, threaded rod; 203, hand wheel; 204, connecting block; 205, plug-in block; 206, threaded column; 207, locking block; 208, jacking column; 209, first light splitter; 210, second light splitter; 211, third light splitter; 3, clamping mechanism; 301, mounting frame; 302, second motor; 303, half tooth; 304, clamping arm; 305, first motor; 306, overhanging frame; 307, laser ranging sensor; 308, connecting disc; 309, rotary joint. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0032] Please refer to Figures 1-7 The embodiment provides the following technical solutions:

[0033] As Figures 1-3 shown, a non-contact length measuring device based on a double-end interference method belongs to the technical field of laser measuring instruments, comprising: a mounting plate 1, a frequency stabilized laser 101 is fixedly installed on the upper surface of the mounting plate 1, a Y-shaped frame 103 is fixedly installed on the upper surface of the frequency stabilized laser 101, a laser emitter 102 of the frequency stabilized laser 101 is fixedly installed in the Y-shaped frame 103, a converging lens 104 is fixedly installed at one end in the Y-shaped frame 103, the converging lens 104 is flush with the laser emitter 102, a first collimating lens 105 and a mirror 106 are fixedly installed at one end on the upper surface of the mounting plate 1, and the first collimating lens 105 and the mirror 106 are also flush with the converging lens 104, and the mirror 106 therein is inclined;

[0034] Wherein, the measurement light emitted by the laser emitter 102 will form a parallel light beam through the converging lens 104 and the first collimating lens 105, and then be reflected by the mirror 106 to the light splitting mechanism 2, which is fixedly installed on the center of the upper surface of the mounting plate 1, and is provided with three groups of light splitting mechanisms (2) arranged in a triangular shape, and the two side light splitting mechanisms 2 are symmetrically arranged, and the workbench 107 is fixedly installed between the three groups of light splitting mechanisms 2, and the clamping mechanism 3 is fixedly installed on the upper surface of the workbench 107, and the clamping mechanism 3 can clamp the measured part;

[0035] Wherein, the measurement light first incident into the light splitting mechanism 2 through the mirror 106 will be divided into two paths, and the measurement light divided into two paths will be incident into the other two groups of light splitting mechanisms 2 at the lower part, and the two groups of light splitting mechanisms 2 at the lower part will divide the measurement light beam into two paths again, one path is incident into the reference mirror 114, and the other path is incident into the outer surface of the measured part clamped by the clamping mechanism 3, and the reference mirror 114 will return the light to the original path to interfere with the reflected light from the surface of the measured part and the light beam reflected by the light splitting mechanism 2 on the other side, forming interference fringes, and the interference fringes on both sides will be collected by the camera 119 again through the second collimating lens 116, and the second collimating lens 116 is fixedly installed on the upper surface of the mounting plate 1 at both ends and is flush with the camera 119, and the reference mirror 114 is connected with the PZT phase shifter 118 through the frame 113 to realize phase-shifting interference measurement;

[0036] Wherein, the PZT phase shifter 118 is fixedly installed in the connecting frame 112, and the frame 113 is fixedly connected with the connecting frame 112, and the connecting arm 111 is rotatably installed on the lower surface of the connecting frame 112, and the other end of the connecting arm 111 is rotatably installed with the fastening plate 110, and the fastening plate 110 is fixedly installed on the upper surface of the mounting plate 1 at both ends, and the camera 119 is fixedly installed on one end of the turnover plate 109, and the turnover plate 109 is rotatably installed in the U-shaped frame 108, and the U-shaped frame 108 is also fixedly installed on the upper surface of the mounting plate 1 at both ends.

[0037] The fastening plate 110 rotatably connected with the connecting arm 111 and one end of the connecting frame 112 are both screwedly installed with the first butterfly bolt 115, so that the first butterfly bolt 115 can be screwed into the end of the connecting arm 111 to realize the locking of rotation, and through the rotary connection, the rotatably installed connecting arm 111 and connecting frame 112 can be angularly turned over.

[0038] The second butterfly bolt 117 is rotatably installed at one end of the U-shaped frame 108, and the other part of the second butterfly bolt 117 can be screwedly threaded through the U-shaped frame 108 to be screwedly pressed at one end of the turnover plate 109 to realize the locking of rotation, and through the turnover action, the camera 119 fixedly installed at one end can be angularly turned over.

[0039] Through the design of the frequency stabilized laser 101, the laser emitter 102, the converging lens 104, the first collimating lens 105, the reflecting mirror 106, the reference mirror 114, the second collimating lens 116, the PZT phase shifter 118, the camera 119, the light splitting mechanism 2 and the clamping mechanism 3, in use, the staff can clamp the measured object in the clamping mechanism 3, and then start the frequency stabilized laser 101 to make the laser emitter 102 emit measuring light to the converging lens 104 first. After the measuring light converges through the converging lens 104, it forms a parallel light beam through the first collimating lens 105. The light beam is incident on the center of the triangularly arranged and symmetrically arranged light splitting mechanism 2 on the upper surface of the mounting plate 1 after changing direction by reflecting on the inclined reflecting mirror 106. In the light splitting mechanism 2, the measuring light is first split into two paths by the first group of light splitting mechanisms 2. The two light beams are respectively incident on the other two groups of light splitting mechanisms 2. The measuring light is again split into two paths at the other two groups of light splitting mechanisms 2, and finally four light beams are formed. Among them, two light beams are respectively incident on the reference mirror 114, and the other two light beams are incident on the outer surface of the measured object clamped by the clamping mechanism 3. The light incident on the reference mirror 114 returns to the original path by virtue of the reflecting performance. At the same time, the light beam incident on the measured object is also reflected from the surface of the measured object. The reflected light of the reference mirror 114 and the reflected light of the surface of the measured object, as well as the light beam reflected by the other side light splitting mechanism 2, interfere with each other to form interference fringes. These interference fringes contain information related to the length of the measured object and are incident into the second collimating lens 116. The second collimating lens 116 collimates the interference fringes to ensure that they are clear and stable, and then they are collected by the camera 119. The camera 119 converts the collected interference fringe image information into electrical or digital signals and transmits them to the subsequent data processing system for length analysis, thereby realizing non-contact measurement. In this process, the reference mirror 114 is connected to the PZT phase shifter 118 through the frame 113. The PZT phase shifter 118 can realize phase shifting interference measurement. By applying different voltage signals to the PZT phase shifter 118, the micro displacement of the reference mirror 114 can be accurately controlled, the phase of the reflected light is changed, and the interference fringe change data under different phases can be more accurately calculated by combining the pre-established mathematical model and algorithm, thereby effectively improving the measurement accuracy and reliability. In addition, the connecting arm 111 is rotatably connected to the fastening plate 110 through the connecting arm 111, and the first butterfly bolt 115 is installed at the connection. When it is necessary to adjust the angle of the reference mirror 114, the first butterfly bolt 115 is loosened, the connecting arm 111 and the connecting frame 112 are rotated to the appropriate angle, and then the first butterfly bolt 115 is tightened for locking, thereby ensuring the stability of the reference mirror 114 during measurement. Similarly, the angle of the camera 119 can be flexibly adjusted and fixed by connecting the camera 119 to the flip plate 109 through the second butterfly bolt 117, so that the camera 119 can clearly and accurately collect the interference fringes.

[0040] As Figure 4 shown, the three-component light mechanism 2 includes three sets of connecting plates 201, which are fixedly installed on the upper surface of the mounting plate 1 and arranged in a triangular shape, and the outer surfaces of the three sets of connecting plates 201 are slidably sleeved with connecting blocks 204, and the upper surfaces of the three sets of connecting blocks 204 are fixedly installed with first, second and third light splitting mirrors 209, 210 and 211, respectively, so that the first, second and third light splitting mirrors 209, 210 and 211 are arranged in a triangular shape.

[0041] The first light splitting mirror 209 splits the measuring light reflected by the reflector 106 into two beams, and the two beams after the first splitting are incident into the second and third light splitting mirrors 210 and 211, respectively, so that the two light splitting mirrors split the received light into two beams each, so that a total of four beams are generated, and then the two beams on both sides are split to the reference mirror 114 and the measured object, and the light reflected by the reference mirror 114 is reflected back along the original path, and the light reflected by the measured object is also reflected back from the surface of the measured object, so that the reflected light of the reference mirror 114 and the reflected light of the measured object and the light reflected by the other light splitting mirror interfere with each other, thereby forming interference fringes, and the interference fringes formed after passing through the second collimating lens 116 are collected by the camera 119.

[0042] The threaded rods 202 are rotatably installed in the three sets of connecting plates 201, the threaded rods 202 are threaded through the connecting blocks 204, and the two ends of the threaded rods 202 are also rotatably threaded out of the connecting plates 201 and fixedly installed with hand wheels 203 at the ends, and one end of the connecting block 204 threaded on the outer surface of the threaded rod 202 is fixedly installed with an insertion block 205, one end of the insertion block 205 is fixedly installed with a threaded column 206, the outer surface of the insertion block 205 is slidably inserted with a locking block 207, and the outer surface of the threaded column 206 is threaded with a pressing column 208, so that the pressing column 208 can be screwed onto the outer surface of the threaded column 206 to push the locking block 207 inward on the outer surface of the insertion block 205, and the locking block 207 can be pushed inward to touch the end of the connecting block 204 and the end of the connecting plate 201 at the same time, so as to realize the locking of the sliding of the connecting block 204.

[0043] Through the design of the first beam splitter 209, the second beam splitter 210 and the third beam splitter 211, the connecting block 204, the threaded rod 202, the threaded column 206, the locking block 207 and the pressing column 208, after the measurement light is reflected by the mirror 106, it will be incident on the first beam splitter 209 arranged in a triangular shape on the mounting plate 1 at a specific angle, and the first beam splitter 209 is fixed on the upper surface of the connecting block 204 and will accurately divide the incident measurement light into two paths by virtue of its optical properties, completing the initial light splitting. This process uses the reflection and transmission principles of the first beam splitter 209 to separate the light beam according to the preset ratio, providing a basic light path branch for subsequent measurement. The two beams after the initial light splitting will be directed to the second beam splitter 210 and the third beam splitter 211 respectively. The second beam splitter 210 and the third beam splitter 211 are also installed on the corresponding connecting block 204, and each divides the received light beam into two beams. Thus, a total of four beams are generated, of which two beams on both sides are directed to the reference mirror 114 and the measured object, respectively. The light reflected by the reference mirror 114 and the surface of the measured object interferes with the light reflected by the other side of the beam splitter, forming interference fringes carrying the length information of the measured object, which is collected by the camera 119 for measurement and calculation. In the structural design of the light splitting mechanism 2, the connecting block 204 installed on the outer surface of the connecting plate 201 and the threaded rod 202 constitute a flexible adjustment system. The staff can rotate the hand wheel 203 to drive the threaded rod 202 to rotate. Since the threaded rod 202 is threadedly connected with the connecting block 204, the connecting block 204 will slide along the outer surface of the connecting plate 201, thereby realizing accurate adjustment of the positions of the first beam splitter 209, the second beam splitter 210 and the third beam splitter 211. This allows the positions of the beam splitters to be flexibly changed according to different measurement requirements, different sizes of measured objects and light path calibration requirements, ensuring that the measurement light can be accurately incident and split. When the positions of the beam splitters are adjusted in place, the pressing column 208 is tightened on the threaded column 206 to push the locking block 207 to slide inward on the outer surface of the plug block 205 until the locking block 207 simultaneously touches and locks the connecting block 204 and the connecting plate 201, thereby firmly locking the connecting block 204 and preventing the positions of the beam splitters from deviating due to factors such as vibration and collision during measurement, ensuring the stability of the light splitting path and the accuracy of the measurement.

[0044] As shown in Figures 5-7 The clamping mechanism 3 includes a first motor 305 fixedly installed on the upper surface of the workbench 107. The output shaft of the first motor 305 is fixedly installed with a connecting disc 308 on the upper surface. The connecting disc 308 is fixedly installed with a mounting frame 301. The outer surfaces of both ends of the mounting frame 301 are rotatably installed with clamping arms 304. The inner surfaces of both groups of clamping arms 304 are fixedly installed with half teeth 303. The two groups of opposite half teeth 303 are engaged with each other, so that the two groups of clamping arms 304 can be synchronously driven to flip outward or clamped towards the center.

[0045] The second motor 302 is fixedly installed in the mounting frame 301, and an output shaft of the second motor 302 penetrates through the mounting frame 301 and is fixedly connected with one of the groups of clamping arms 304.

[0046] The first motor 305 is fixedly installed on the outer surface of the first motor 305, and the overhanging frame 306 is fixedly installed in the overhanging frame 306. The laser ranging sensor 307 is flush with the rotating ring 309, and the rotating ring 309 is fixedly installed on the lower surface of the connecting disc 308. The outer surface of the rotating ring 309 is in the shape of an ellipse from narrow to wide, so that when the rotating ring 309 is rotated by the first motor 305, the distance between the rotating ring 309 and the laser ranging sensor 307 will change constantly. The laser ranging sensor 307 continuously detects the distance between the two, and transmits the data to the controller. The controller has a pre-set corresponding relationship model between the distance and the angle, and according to the received different distance data, the distance change is converted into the angle information of the rotating ring 309 by algorithm conversion, so as to realize the measurement and feedback of the rotating angle. The control output end of the controller is electrically connected with the electric control end of the first motor 305.

[0047] The model of the laser ranging sensor 307 and the controller is AMS307i120 and S7-1500 respectively.

[0048] The distance-angle corresponding relationship model is as follows:

[0049] 1. Geometric model establishment

[0050] Assumed conditions:

[0051] The rotating ring is a standard ellipse, and the equation is The long axis a and the short axis b;

[0052] The laser ranging sensor is fixed on the center axis of the ellipse, and the initial position corresponds to the rotating ring angle θ=0°.

[0053] Coordinate transformation:

[0054] After the rotating ring is rotated by an angle θ, the coordinates of the contact point on the ellipse are (acosθ,bsinθ).

[0055] Distance formula:

[0056] The distance from the sensor to the contact point Where

[0057] (x0,y0) is the offset of the sensor installation position relative to the center of the ellipse.

[0058] If the sensor is located at the center of the ellipse (x0=0,y0=0), it is simplified as:

[0059]

[0060] 2. Calibration method

[0061] Steps:

[0062] a. Rotate the rotary ring to a known angle θ i (e.g. 0°, 90°, 180°), record the sensor output distance d i ;

[0063] b. Fit the d(θ) curve, solve the ellipse parameters a, b and installation offset (x0, y0);

[0064] c. When measuring in real time, get the rotation angle by the inverse equation θ = f(d).

[0065] Error compensation:

[0066] Introduce temperature sensors to correct the oval deformation caused by thermal expansion, or use oval fitting algorithm for dynamic calibration.

[0067] 3. Controller implementation

[0068] Write the calibration algorithm in PLC / S7-1500, calculate θ in real time and feedback to the first motor 305, forming a closed-loop control.

[0069] By the design of the first motor 305, the second motor 302, the clamping arm 304, the half tooth 303, the laser ranging sensor 307 and the rotating ring 309, when the measured object is placed, the second motor 302 can be started to drive a set of clamping arms 304 fixedly connected thereto to rotate, and because the half teeth 303 inside the two sets of clamping arms 304 are meshed with each other, the rotating clamping arms 304 can drive the other set of clamping arms 304 to move synchronously, so that the two sets of clamping arms 304 are clamped towards the center, thereby stably clamping the measured object in the middle, and through the structure design of the meshing of the two sets of half teeth 303, the synchronism of the clamping arm 304 action is ensured, which can provide uniform clamping force, ensure that measured objects of different shapes and sizes can be stably fixed, reduce measurement errors caused by unstable clamping, and this symmetrical and synchronous clamping method can not only adapt to measured objects of different shapes and sizes, but also provide uniform and stable clamping force, avoid the position deviation of the measured object caused by uneven force, effectively reduce the measurement error, and significantly improve the reliability of the measurement result. After the clamping of the measured object is completed, the first motor 305 can be started to drive the connecting disc 308 to rotate, and the connecting disc 308 can drive the mounting frame 301 fixedly installed on the upper surface and the clamped measured object to rotate together, and the rotating ring 309 fixedly installed on the lower surface of the connecting disc 308 is also driven to rotate, and the outer surface of the rotating ring 309 is specially oval, and is opposite to the laser ranging sensor 307 in the suspended frame 306. During the rotation of the connecting disc 308, the distance between the rotating ring 309 and the laser ranging sensor 307 changes constantly with the change of the oval contour of the rotating ring 309, and in this process, the laser ranging sensor 307 detects the distance between them in real time and transmits the data to the controller. The controller has a pre-set corresponding relationship model of distance and angle, which converts the received distance data into angle information of the rotation of the rotating ring 309 through algorithm, and at the same time, the controller is connected with the electric control end of the first motor 305 to form a closed-loop control system. When the controller judges that there is a deviation in the rotation angle according to the angle information, it will timely adjust the running state of the first motor 305 to ensure that the measured object is driven to rotate to the accurate angle, providing accurate positioning basis for subsequent length measurement based on the double-end interference method, thereby ensuring the accuracy and effectiveness of the whole measurement process.

[0070] According to the above technical scheme, the working steps of the present scheme are summarized and combed: when measuring the measured piece, the second motor 302 can be started to drive a group of clamping arms 304 fixedly connected thereto to rotate, and because the half teeth 303 on the inner sides of the two groups of clamping arms 304 are meshed with each other, the rotating clamping arms 304 can drive the other group of clamping arms 304 to move synchronously, so that the two groups of clamping arms 304 are clamped towards the center, thereby stably clamping the measured piece in the middle. After the measured piece is clamped, the first motor 305 can be started to drive the connecting disc 308 to rotate, and the connecting disc 308 can drive the mounting frame 301 fixedly installed on the upper surface and the clamped measured piece to rotate together. The rotary ring 309 fixedly installed on the lower surface of the connecting disc 308 is also driven to rotate. The outer surface of the rotary ring 309 is specially oval-shaped and opposite to the laser ranging sensor 307 in the suspended frame 306. During the rotation of the connecting disc 308, the distance between the rotary ring 309 and the laser ranging sensor 307 changes with the change of the elliptical contour of the rotary ring 309. The laser ranging sensor 307 detects the distance in real time and transmits the data to the controller. The controller has a pre-set corresponding relationship model between the distance and the angle. The received distance data is converted into the angle information of the rotation of the rotary ring 309 by algorithm. At the same time, the controller is connected to the electric control end of the first motor 305 to form a closed-loop control system. When the controller determines that there is a deviation in the rotation angle according to the angle information, it can timely adjust the running state of the first motor 305 to ensure that the measured piece is driven to rotate to the accurate angle. After the measured piece is rotated to the required angle, the stable frequency laser 101 can be started to make the laser emitter 102 emit measuring light to the converging lens 104 first. The measuring light converges through the converging lens 104 and then forms a parallel light beam through the first collimating lens 105. The light beam is incident on the first beam splitter 209 arranged in a triangular shape and symmetrically on the upper surface of the mounting plate 1. The first beam splitter 209 is fixed on the upper surface of the connecting block 204 and accurately divides the incident measuring light into two paths by virtue of its optical properties. The two beams of light after the first splitting are respectively incident on the second beam splitter 210 and the third beam splitter 211. The second beam splitter 210 and the third beam splitter 211 are also installed on the corresponding connecting block 204 and divide the received light beams into two beams again. Thus, four beams of light are generated, of which the two beams of light on the two sides are respectively incident on the reference mirror 114 and the measured piece. The light reflected by the reference mirror 114 and the surface of the measured piece interferes with the light beam reflected by the other beam splitter to form interference fringes carrying the length information of the measured piece. The interference fringes containing the length information of the measured piece are incident into the second collimating lens 116. The second collimating lens 116 collimates the interference fringes to ensure that they are clear and stable, and then the camera 119 collects them. The camera 119 converts the collected interference fringe image information into an electrical signal or a digital signal and transmits it to the subsequent data processing system for length analysis.That is, the contactless measurement function is realized, and in the process, the reference mirror 114 is connected with the PZT phase shifter 118 through the frame 113, the PZT phase shifter 118 can realize the phase shift interference measurement, by applying different voltage signals to the PZT phase shifter 118, the micro displacement of the reference mirror 114 can be accurately controlled, the phase of the incident reflected light is changed, the interference fringe change data under different phases is changed, combined with the pre-established mathematical model and algorithm, the length of the measured piece can be more accurately calculated, the measurement precision and reliability are effectively improved.

[0071] In summary: the device adopts the interference method to measure the length of the end degree standardizer, does not need to be directly contacted with the measured piece, avoids the damage such as scratch and wear caused to the surface of the measured piece by the traditional measurement method, is especially suitable for the measurement of the precise and easily damaged measured piece, meanwhile, reduces the loss of the measurement tool and the maintenance cost.

[0072] The part not involved in the present application is the same as the prior art or can be realized by using the prior art. Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by

[0073] The appended claims and their equivalents define.

Claims

1. A non-contact length measuring device based on two-end interferometry, characterized by, Include: The installation plate (1), the upper surface of the installation plate (1) is fixedly installed with a frequency stabilization laser (101), the upper surface of the frequency stabilization laser (101) is fixedly installed with a Y-shaped frame (103), the Y-shaped frame (103) is fixedly installed with a laser emitter (102) of the frequency stabilization laser (101) in it, and one end of the Y-shaped frame (103) is fixedly installed with a converging lens (104), the converging lens (104) is flush with the laser emitter (102), one end of the upper surface of the installation plate (1) is fixedly installed with a first collimating lens (105) and a mirror (106), and the first collimating lens (105) and the mirror (106) are also flush with the converging lens (104), wherein the mirror (106) is inclined; The measuring light emitted by the laser emitter (102) will form a quasi-parallel light beam through the converging lens (104) and the first collimating lens (105) in turn, and then be reflected into the light splitting mechanism (2) at one end of the mirror (106), the light splitting mechanism (2) is fixedly installed at the center of the upper surface of the installation plate (1), and is provided with three groups, three groups of light splitting mechanisms (2) are arranged in a triangular shape, and the light splitting mechanisms (2) on both sides are symmetrically arranged, and a workbench (107) is fixedly installed between three groups of light splitting mechanisms (2), a clamping mechanism (3) is fixedly installed on the upper surface of the workbench (107), and the clamping mechanism (3) can clamp and fix the measured part; The clamping mechanism (3) comprises a first motor (305), the first motor (305) is fixedly installed on the upper surface of the workbench (107), a connecting disc (308) is fixedly installed on the outer surface of the output shaft of the first motor (305), an installation frame (301) is fixedly installed on the upper surface of the connecting disc (308), and a clamping arm (304) is rotatably installed on the outer surface of both ends of the installation frame (301). The inner side of the two groups of clamping arms (304) is fixedly installed with a half tooth (303), and the two groups of opposite half teeth (303) are engaged with each other, so that the two groups of clamping arms (304) can be synchronously driven to turn outward or be clamped to the center; A second motor (302) is fixedly installed in the installation frame (301), and the output shaft of the second motor (302) penetrates the installation frame (301) and is fixedly connected with one of the clamping arms (304). The outer surface of the first motor (305) is fixedly installed with a cantilever frame (306), the cantilever frame (306) is fixedly installed with a laser ranging sensor (307) inside, the laser ranging sensor (307) is flush with a rotating ring (309), the rotating ring (309) is fixedly installed at the lower surface of a connecting disc (308), and the outer surface of the rotating ring (309) is in the shape of an ellipse from narrow to wide, so that when the rotating ring (309) is rotated by the first motor (305), the distance between the rotating ring (309) and the laser ranging sensor (307) will change constantly, and the laser ranging sensor (307) will continuously detect the distance between them and transmit data to the controller, and the controller has a pre-set corresponding relationship model between distance and angle, according to the received different distance data, through algorithm conversion, the distance change is converted into the angle information of the rotation of the rotating ring (309), so as to realize the measurement and feedback of the rotation angle, and the control output end of the controller is electrically connected with the electric control end of the first motor (305).

2. A non-contact length measuring device based on dual -end interferometry according to claim 1, characterized in that: The measurement light first incident into the light splitting mechanism (2) through the reflecting mirror (106) will be divided into two paths, and the measurement light divided into two paths will be incident onto the other two groups of light splitting mechanisms (2) in the lower part, and the two light splitting mechanisms (2) in the lower part will divide the measurement light beam into two paths again, one path is incident onto the reference mirror (114), and the other path is incident onto the outer surface of the measured member clamped by the clamping mechanism (3), and the reference mirror (114) will return the light to the original path to interfere with the reflected light from the surface of the measured member and the light beam reflected by the light splitting mechanism (2) on the other side, forming interference fringes, the interference fringes on both sides will be collected by the camera (119) again through the second collimating lens (116), the second collimating lens (116) is fixedly installed on the upper surface of the mounting plate (1) and flush with the camera (119), the reference mirror (114) is connected with the PZT phase shifter (118) through the frame (113), realizing phase-shifting interference measurement; The PZT phase shifter (118) is fixedly installed in the connecting frame (112), the frame (113) is fixedly connected with the connecting frame (112), the connecting arm (111) is rotatably installed on the lower surface of the connecting frame (112), the other end of the connecting arm (111) is rotatably installed with the fastening plate (110), the fastening plate (110) is fixedly installed on the upper surface of the mounting plate (1), and the camera (119) is fixedly installed on one end of the turnover plate (109), the turnover plate (109) is rotatably installed in the o-shaped frame (108), and the o-shaped frame (108) is also fixedly installed on the upper surface of the mounting plate (1).

3. A non-contact length measuring device based on dual -end interferometry according to claim 2, characterized in that: The fastening plate (110) and the one end of the connecting frame (112) which are rotationally connected with the connecting arm (111) are both screw-mounted with the first butterfly bolt (115), the first butterfly bolt (115) can be rotationally locked by screwing into the one end of the connecting arm (111) to press, and through the rotational connection, the connecting arm (111) and the connecting frame (112) which are rotationally installed can be angularly flipped.

4. A non-contact length measuring device based on dual -end interferometry according to claim 3, characterized in that: The one end of the U-shaped frame (108) is rotationally installed with the second butterfly bolt (117), the other part of the second butterfly bolt (117) can be screw-threaded through the U-shaped frame (108) to press on the one end of the flipping plate (109) to realize the rotational locking, and through the flipping, the camera (119) which is fixedly installed on the one end can be angularly flipped.

5. A non-contact length measuring device based on dual -end interferometry according to claim 4, characterized in that: The three groups of the light splitting mechanisms (2) include three groups of connecting plates (201), the three groups of the connecting plates (201) are fixedly installed on the upper surface of the mounting plate (1) and are arranged in a triangle, the outer surfaces of the three groups of the connecting plates (201) are all slidingly sleeved with connecting blocks (204), and the upper surfaces of the three groups of the connecting blocks (204) are respectively fixedly installed with the first light splitting mirror (209), the second light splitting mirror (210) and the third light splitting mirror (211), so that the first light splitting mirror (209), the second light splitting mirror (210) and the third light splitting mirror (211) are arranged in a triangle.

6. A non-contact length measuring device based on dual -end interferometry according to claim 5, characterized in that: The first light splitting mirror (209) will split the measuring light reflected by the reflector (106) into two paths, and the two beams of light after the initial light splitting will be respectively incident into the second light splitting mirror (210) and the third light splitting mirror (211), so that the two light splitting mirrors split the received light into two beams again, so that a total of four beams of light are generated, and then the two beams of light on both sides are split to the reference mirror (114) and the measured object, the light to the reference mirror (114) is reflected back, and the light to the measured object is also reflected back from the surface of the measured object, so that the reflected light of the reference mirror (114) and the reflected light of the measured object and the light reflected by the other light splitting mirror interfere with each other, thereby forming interference fringes, and the interference fringes formed after passing through the second collimating lens (116) are collected by the camera (119).

7. A non-contact length measuring device based on dual -end interferometry according to claim 6, characterized in that: Three groups of connecting plates (201) are rotatably installed with threaded rods (202), the threaded rods (202) are threaded through from the connecting blocks (204), and both ends of the threaded rods (202) are also rotatably threaded out from the connecting plates (201) and fixedly installed with hand wheels (203) at the end portions, and the connecting blocks (204) fixedly installed at one end of the threaded rods (202) are threaded with plug blocks (205) at the outer surfaces, one end of the plug blocks (205) is fixedly installed with threaded columns (206), the outer surfaces of the plug blocks (205) are slidably inserted with locking blocks (207), and the outer surfaces of the threaded columns (206) are threaded with top pressing columns (208), so that the top pressing columns (208) can be screwed onto the outer surfaces of the threaded columns (206) to push the locking blocks (207) to slide inward on the outer surfaces of the plug blocks (205), and then the locking blocks (207) sliding inward can be in contact with one end of the connecting blocks (204) and one end of the connecting plates (201) at the same time, so as to realize the sliding locking of the connecting blocks (204).

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