CN114942016A - Vertical laser pointing correction device and method based on interference fringe decoupling - Google Patents

Abstract

The invention discloses a vertical laser pointing correction device and method based on interference fringe decoupling, comprising: obtaining a vertical laser signal through a vertical laser generating module, transmitting the vertical laser signal to an integrated sensing module, The chemical sensing module generates a spatial interference image; the spatial interference image is input into the signal processing module for high-precision decoupling operation to obtain the angle deviation result of the vertical laser relative to the direction of gravity, and real-time correction of the vertical laser pointing is realized according to the angle deviation result. . The vertical laser pointing correction device of the present invention is completely based on the principle of laser interferometry, has high measurement resolution, and the angle measurement result can be directly traced to the laser wavelength, which meets the requirements of high-end equipment for ultra-precise vertical laser pointing. In addition, the integrated sensing module of the device of the present invention is convenient for disassembly and repeated installation, which is convenient for reuse in multiple sets of devices, and saves costs.

Description

A device and method for vertical laser pointing correction based on interference fringe decoupling

technical field

The invention belongs to the technical field of precise angle measurement, and in particular relates to a vertical laser pointing correction device and method based on interference fringe decoupling.

Background technique

The vertical laser based on gravity is widely used to determine the vertical reference line and measure the slight deviation relative to the plumb line, and has important application value in engineering construction and precision measurement. For example, it can be used to measure and ensure the verticality of buildings, elevators, dams and other buildings, and can also be used for the precision detection of verticality and straightness of mechanical structures such as guide rails, as well as the measurement and correction of torsion. With the rapid development of precision engineering in recent years, high-end equipment has put forward higher requirements for the pointing accuracy of vertical lasers. For example, in the mass unit "Kg" quantization reference device, the pointing accuracy of the vertical laser determines the overall accuracy of the device, and the pointing of the vertical laser must be ultra-precisely measured and corrected to ensure that it coincides with the direction of gravity.

The vertical collimator can generate vertical laser based on gravity and use it as a plumb line, which is often used in construction monitoring of large buildings and installation of mechanical equipment. Generally, equipment such as collimator, pentagonal prism, rectangular coordinate plate and steel ruler are used to calibrate the coaxiality between the vertical laser and the vertical axis in the vertical collimator. Chinese Patent Publication No. CN104949689A, published on September 30, 2015, invented the "Digital Calibration Method and Device of Laser Pivot Instrument Based on Source Imaging", which images the reticle through an imaging light source, and then projects the image to infinity On the target, the calibration is compared with the debugging reference center, which reduces the complexity of calibration and detection and improves the accuracy to a certain extent. However, due to factors such as the levelness of the workbench, the accuracy of the measuring ruler, and the inaccurate readings of the human eye, the vertical laser generated by the vertical collimator has the problems of low pointing accuracy and difficult to guarantee traceability in principle, and it is difficult to be used for ultra-high Precision measurement.

In the field of precision metrology, some scholars have also proposed vertical laser pointing measurement devices based on new principles. For example, in 2016, the article "Flat mirror level adjustment method based on high-precision electronic level" was published in the 37th volume of the 4th issue of the Chinese Journal of Instrumentation, which proposed a method to trace the vertical laser point to the level through the least transfer link. This method Firstly, the horizontal attitude of the plane mirror is adjusted based on a high-precision electronic level, and then the vertical beam pointing of the laser interferometer is corrected by using the plane mirror as a reference. The device finally achieves a synthetic standard uncertainty of 41 μrad for the vertical laser pointing, which is affected by the accuracy of the rotary axis of the rotary table, the accuracy of the leveling mechanism of the rotary table, the influence of the lead wire of the electronic level, and the nonlinearity and machining accuracy of the electronic level itself. It is seriously limited, which directly limits the pointing accuracy of the vertical beam, and the traceability is also poor. Furthermore, the device cannot use the measurements for feedback control to achieve real-time correction of beam pointing.

Another example, in 2016, the 55th issue of Applied Optics published the article "System for the measurement of the deviation of a laser beam from the vertical direction", which proposed a vertical laser pointing deviation measurement device based on the principle of laser self-collimation. face as a benchmark. It divides the vertical laser into two beams, one beam passes through the corner mirror and then passes through the lens, and the other beam passes through the lens after being reflected by the liquid surface. The short-term stability of the device can reach 2.4 μrad, but due to the processing error and positional installation error of optical components such as CCD and converging lens, the measurement accuracy of the device is directly limited, and the traceability is difficult to improve. In addition, the device can only measure the deviation angle of the laser pointing, and cannot correct it to the direction of gravity.

To sum up, the traditional vertical laser pointing calibration method for vertical collimators has low accuracy, and in principle cannot trace the beam direction to the direction of gravity; the vertical laser pointing correction device based on electronic level is limited by factors such as processing errors. , the accuracy is limited, and the traceability is also poor; the vertical laser pointing measurement device based on the principle of self-collimation is limited by the assembly error of the optical components, and the measurement results are still difficult to trace directly. Furthermore, the above devices cannot take measurements of beam pointing for real-time feedback and correct them to the direction of gravity. Therefore, there is currently a lack of a direct traceable high-precision vertical laser pointing correction device in the technical field of precise angle measurement.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a vertical laser pointing correction device and method based on interference fringe decoupling, which can realize high-precision measurement and correction of vertical laser pointing, and directly trace the source to the direction of gravity.

In order to achieve the above object, the present invention provides the following solution: a vertical laser pointing correction device based on interference fringe decoupling, comprising:

a vertical laser generating module for generating a vertical laser signal and fine-tuning the direction of the vertical laser signal;

an integrated sensing module, connected to the vertical laser generating module, for receiving the vertical laser signal, and generating a spatial interference image based on the vertical laser signal;

A signal processing module, connected with the integrated sensing module, is used to perform high-precision decoupling operation on the spatial interference image, and obtain the angle deviation result of the vertical laser relative to the direction of gravity. According to the angle deviation result, realize Real-time correction of vertical laser pointing.

Preferably, the vertical laser generating module includes a single-frequency laser, a single-mode polarization-maintaining fiber, a fiber collimator, a pentagonal prism, an integrated light source base, and a two-dimensional precision angle turntable;

The single-frequency laser is used to provide a frequency-stabilized laser signal;

The single-mode polarization-maintaining fiber is connected to the single-frequency laser, and is used for conducting the frequency-stabilized laser signal to the fiber collimator;

The fiber collimator is connected to the single-mode polarization-maintaining fiber, and is used for receiving the frequency-stabilized laser signal and outputting the collimated laser;

The pentagonal prism is used for receiving the collimated laser light and outputting a vertical laser signal;

The integrated light source base is used for fixing the optical fiber collimator and the pentagonal prism;

The two-dimensional precision angle turntable is used for placing the integrated sensing base and the integrated light source base.

Preferably, the integrated sensing module includes an integrated sensing base, a beam splitting corner prism, a beam splitter, a reflector, a polarizing beam splitter, a quarter-wave plate, a liquid container unit, a liquid unit, and a micro-corner array. ,Image Sensor;

The integrated sensing base is used to fix the beam splitter cube prism, beam splitter, reflector, polarized beam splitter, quarter wave plate, liquid container unit, liquid unit, and image sensor;

the beam splitting corner prism is used for transmitting the vertical laser signal and reflecting part of the vertical laser signal to the first beam splitter;

The spectroscope is used for dividing the vertical laser signal into transmitted light and reflected light;

the reflecting mirror is used for reflecting the reflected light to the polarizing beam splitter;

The polarizing beam splitter is used to transmit the transmitted light and reflected light whose polarization state is P to the quarter-wave plate; and is used to reflect the first liquid surface refracted light and the first liquid surface reflection whose polarization state is S light, the second liquid surface refracted light, and the second liquid surface reflected light to obtain the first signal light, the second signal light, the third signal light, and the fourth signal light and send them to the image sensor;

The quarter wave plate is used to transmit the transmitted light and reflected light, and convert it into circularly polarized light; it is used to refract the first liquid surface refracted light, the first liquid surface reflected light, and the second liquid surface refracted light The polarization state of the light and the light reflected from the second liquid surface becomes S;

The liquid container unit is used to place the liquid in the liquid unit; it is used to reflect the second liquid surface refracted light on the bottom surface to a quarter-wave plate;

The liquid unit is used for dividing the transmitted light and reflected light into circularly polarized light through the liquid surface into first liquid surface refracted light and first liquid surface reflected light; second liquid surface refracted light and second liquid surface refracted light Surface reflected light; used to reflect the first liquid surface reflected light and the second liquid surface reflected light to a quarter wave plate;

The micro-pyramid array is arranged at the bottom of the liquid container unit, and is used for reflecting the first liquid surface refracted light to a quarter-wave plate;

The image sensor is used to detect the spatial interference light spot formed by the interference of the first signal light and the second signal light; and used to detect the spatial interference fringes formed by the interference of the third signal light and the fourth signal light.

Preferably, the spatial interference light spot and the spatial interference fringe do not overlap in space.

Preferably, the signal processing module includes a host computer and a signal processing card;

The signal processing card is used to perform high-precision decoupling operation on the interference signal through the spatial interference fringe decoupling algorithm, and send a feedback control signal to the two-dimensional precision angle turntable according to the measurement result to correct the vertical laser pointing and trace the source to the direction of gravity. , and upload the operation result to the upper computer;

The upper computer is used for receiving, displaying and storing the measurement results of the vertical laser pointing correction.

A vertical laser pointing correction method based on interference fringe decoupling, comprising,

Obtain a vertical laser signal through a vertical laser generating module, transmit the vertical laser signal to an integrated sensing module, and generate a spatial interference image based on the integrated sensing module;

The spatial interference image is input into the signal processing module for high-precision decoupling operation to obtain the angular deviation result of the vertical laser relative to the gravitational direction, and real-time correction of the vertical laser pointing is realized according to the angular deviation result.

Preferably, the vertical laser signal is obtained by a vertical laser generating module, and the process of transmitting the vertical laser signal to the integrated sensing module includes: generating a frequency-stabilized laser signal by a single-frequency laser, and converting the signal to a single-mode polarization-maintaining fiber through a single-mode polarization-maintaining fiber. The frequency-stabilized laser signal is conducted to a fiber collimator; the fiber collimator outputs a collimated laser, and after the collimated laser obtains a vertical laser signal through a pentagonal prism, the vertical laser signal is transmitted to the integrated sensor module.

Preferably, the process of generating a spatial interference image based on the integrated sensing module includes:

The vertical laser signal is reflected by the beam splitter corner prism and then returns in the original direction, and is divided into transmitted light and reflected light by the beam splitter;

The transmitted light is transmitted through a polarizing beam splitter and a quarter-wave plate to obtain circularly polarized light; the circularly polarized light is divided into the first liquid surface refracted light and the first liquid surface reflected light on the surface of the liquid unit;

The reflected light is reflected by the mirror, and then transmitted through a polarizing beam splitter and a quarter-wave plate to obtain circularly polarized light; the circularly polarized light is divided into a second liquid surface refracted light and a second liquid surface refracted light on the surface of the liquid unit. liquid surface reflected light;

The first liquid surface refracted light is reflected by the micro-pyramid array at the bottom of the liquid container unit and returns to the original path, and the polarization state becomes S after passing through the quarter-wave plate in the reverse direction, and then becomes the first after being reflected by the polarization beam splitter. The signal light is directed to the image sensor;

The first liquid surface reflected light and the second liquid surface reflected light are reflected by the liquid, and the polarization state changes to S after passing through the quarter-wave plate in the reverse direction, and then becomes the second signal light and the fourth signal light after being reflected by the polarization beam splitter. The signal light is directed to the image sensor;

The second liquid surface refracted light is reflected by the bottom surface of the liquid container, and the polarization state changes to S after passing through the quarter-wave plate in the reverse direction, and then becomes the third signal light after being reflected by the polarization beam splitter and is directed to the image sensor;

The first signal light and the second signal light interfere on the detection surface of the image sensor to obtain spatial interference light spots; the third signal light and the fourth signal light interfere on the detection surface of the image sensor to obtain spatial interference fringes; The spatial interference light spot and the spatial interference fringe do not overlap in space.

Preferably, the real-time correction process of the vertical laser pointing includes:

Send the spatial interference image to the signal processing card, and the signal processing card traces the vertical laser signal to the absolute gravity direction through the angle modulation of the two-dimensional precision angle turntable and the Gaussian fitting of the spatial interference light spot, Then perform the interference fringe decoupling algorithm on the spatial interference fringes to realize the precise measurement of the vertical laser pointing, and finally send a feedback control signal to the two-dimensional precision angle turntable according to the measurement results to realize the real-time correction of the vertical laser pointing, and upload the measurement results at the same time. to the host computer.

Preferably, the process of performing an interference image decoupling algorithm on the spatial interference image includes,

Convert the spatial interference fringes into a two-dimensional grayscale matrix, perform a two-dimensional discrete Fourier transform based on butterfly operation on the two-dimensional grayscale matrix, and obtain the frequency space matrix of the spatial interference fringes. The amplitude space of , calculates different spatial frequency components;

Obtain the maximum amplitude point and its corresponding position in the frequency space matrix based on the amplitude space of the spatial interference fringe spectrum, and use the amplitude information of the maximum amplitude point and the adjacent matrix points to perform two-dimensional curve peak fitting, and obtain The exact frequency coordinates after fitting;

According to the X-direction and Y-direction components of the accurate frequency coordinates obtained by fitting, the horizontal inclination angles of the X-direction and the Y-direction are obtained respectively according to the formula that the angle measurement value is linearly related to the spatial frequency of the spatial interference fringes.

The present invention discloses the following technical effects:

(1) The vertical laser pointing correction device and method based on interference fringe decoupling provided by the present invention are completely based on the principle of laser interferometry, take the horizontal plane as the reference plane, and have high measurement resolution, which can directly trace the beam pointing to the direction of gravity.

(2) The invention ensures the contrast and signal-to-noise ratio of the interference signal by means of the conversion of the laser polarization state and the matching of the reflectivity of the liquid surface, the bottom surface of the liquid container and the reflectivity of the micro-pyramid array, and the angle measurement results can be traced back to laser wavelength.

(3) On the basis of the precise measurement of the vertical laser pointing, the present invention further realizes the real-time feedback precise correction of the beam pointing.

(4) The integrated sensing module of the device of the present invention is convenient for disassembly and repeated installation, which is convenient for reuse in multiple sets of devices and saves costs.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic diagram of a system structure according to an embodiment of the present invention;

1-host computer, 2-image sensor, 3-beam splitting corner prism, 4-integrated sensing base, 5-beamsplitter, 6-reflector, 7-polarization beamsplitter, 8-quarter wave plate, 9-Micro pyramid array, 10-Liquid container, 11-Liquid, 12-Two-dimensional precision angle turntable, 13-Pentagon prism, 14-Integrated light source base, 15-Fiber collimator, 16-Single frequency laser, 17- -Single-mode polarization-maintaining fiber, 18-signal processing card.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, the vertical laser pointing correction device based on interference fringe decoupling includes a host computer 1, an image sensor 2, a beam splitting corner prism 3, an integrated sensing base 4, a beam splitter 5, a reflector 6, a polarization mirror Beam splitter 7, quarter wave plate 8, micro pyramid array 9, liquid container 10, liquid 11, two-dimensional precision angle turntable 12, pentagonal prism 13, integrated light source base 14, fiber collimator 15, single frequency Laser 16, single-mode polarization maintaining fiber 17 and signal processing card 18;

Among them, the fiber collimator 15 and the pentagonal prism 13 are fixed on the integrated light source base 14; and the image sensor 2 are fixed on the integrated sensing base 4; the integrated sensing base 4 and the integrated light source base 14 are both located on the two-dimensional precision angle turntable 12; the integrated sensing module can be disassembled or installed at any time, and is compatible with The integrated light source base is located on the same plane.

The liquid container 10 is a circular shape with a diameter of 50mm, made of a transparent material and coated with a light-absorbing material; its bottom surface is a slope, and the angles in the X and Y directions relative to the integrated base 4 are in the order of milliradians. One side is coated with a partially reflective film, and the reflectivity is equivalent to the reflectivity of the liquid in the laser band used, that is, the reflectivity of the 633 nm band laser is 3%; The laser wavelength used is equivalent to the reflectivity of the liquid, that is, the reflectivity of the laser in the 633nm band is 3%; the liquid 11 is silicone oil, its viscosity is 350CS, the reflectivity is about 3%, the refractive index is 1.4, and the liquid level height is 2mm. reference datum.

As shown in FIG. 1 , the vertical laser pointing correction device based on interference fringe decoupling provided by the present invention includes: a vertical laser generating module, an integrated sensing module, and a signal processing module;

Among them, the vertical laser generation module includes a single-frequency laser, a single-mode polarization-maintaining fiber, a fiber collimator, a pentagonal prism, an integrated light source base, and a two-dimensional precision angle turntable. Point for fine-tuning;

The integrated sensing module includes an integrated sensing base, a beam splitter cube prism, a beam splitter, a reflector, a polarizing beam splitter, a quarter wave plate, a liquid container, a liquid, a micro cube corner array, and an image sensor;

The working principle of the vertical laser pointing correction device is as follows: a 633nm single-frequency helium-neon laser 16 provides a frequency-stabilized laser signal, and the laser signal is linearly polarized light, which is conducted to a fiber collimator 15 through a single-mode polarization-maintaining fiber 17, and the fiber The collimator 15 outputs a collimated laser whose polarization state is P, and becomes a vertical laser signal after passing through the pentagonal prism 13;

Part of the vertical laser signal is reflected by the beam splitter corner prism 3 and returns in the original direction, and is divided into transmitted light and reflected light by the beam splitter 5; The circularly polarized light is divided into the first liquid surface refracted light and the first liquid surface reflected light on the surface of the liquid 11; the reflected light is reflected by the mirror 6, and then transmitted by the polarizing beam splitter 7 and the quarter wave plate 8 , becomes circularly polarized light, and is divided into the second liquid surface refracted light and the second liquid surface reflected light on the surface of the liquid 11; Returning, the polarization state changes to S after passing through the quarter-wave plate 8 in the reverse direction, and is reflected by the polarization beam splitter 7 to become the first signal light and directed to the image sensor 2; the first liquid surface reflected light is reflected by the liquid 11, After passing through the quarter-wave plate 8 in reverse, the polarization state becomes S, and after being reflected by the polarization beam splitter 7, it becomes the second signal light and is directed to the image sensor 2; the second liquid surface refracted light is reflected by the bottom surface of the liquid container 10 , the polarization state changes to S after passing through the quarter-wave plate 8 in the reverse direction, and then becomes the third signal light after being reflected by the polarization beam splitter 7 and is directed to the image sensor 2; the second liquid surface reflected light is reflected by the liquid 11, After passing through the quarter wave plate 8, the polarization state becomes S, and after being reflected by the polarization beam splitter 7, it becomes the fourth signal light and is directed to the image sensor 2; the first signal light and the second signal light are in the image sensor 2. The detection surface interferes to form a spatial interference light spot; the third signal light and the fourth signal light interfere on the detection surface of the image sensor 2 to form a spatial interference fringe; the spatial interference light spot and the spatial interference fringe do not overlap; the spatial interference light spot and the spatial interference The fringes are sent to the signal processing card 18 in the form of digital quantities. The signal processing card 18 integrates the spatial interference fringe decoupling algorithm to perform high-precision decoupling operations on the interference signal, and send feedback control to the two-dimensional precision angle turntable 12 according to the measurement results. Signal, the vertical laser point is corrected and traced to the direction of gravity, and the measurement results are sent to the upper computer 1 at the same time.

Further, the correction method for vertical laser pointing includes:

Step 1, vertical laser pointing pre-adjustment: the signal processing card drives the two-dimensional precision angle turntable to rotate around the X-axis and the Y-axis respectively, so that the spatial interference spot is approximately circular;

Step 2, adjustment of the initial value of the angle in the X direction: the signal processing card drives the two-dimensional precision angle turntable to reciprocate around the Y axis, and performs sinusoidal modulation on the pointing of the vertical laser along the X direction, and the modulation frequency is f _m ; Real-time Gaussian fitting is performed on the intensity distribution of the spatial interference light spot, and the half-height width d _x of the fitting curve is recorded; the center angle value of the two-dimensional precision angle turntable is adjusted around the Y axis, so that the d _x curve becomes a sinusoidal curve with a frequency of 2f _m , at this time d _x reaches the maximum value d _x-max when the turntable is at the center angle value;

Step 3, the initial value adjustment of the Y direction angle: the signal processing card drives the two-dimensional precision angle turntable to reciprocate around the X axis, and performs sinusoidal modulation on the direction of the vertical laser along the Y direction, and the modulation frequency is f _m ; Real-time Gaussian fitting is performed on the intensity distribution of the spatial interference spot, and the half-height width _dy of the fitting curve is recorded; the central angle value of the two-dimensional precision angle turntable is adjusted around the X-axis, so that the _dy curve becomes a sine curve with a frequency of 2f _m , at this time dy reaches the maximum value _{dy -max} when the turntable is at the center angle value;

Step 4: Correction of the initial value of vertical laser pointing: stop the angle modulation of the two-dimensional precision angle turntable so that it is at the above-mentioned central angle value in both the X and Y directions, and the half height of the spatial interference spot along the X and Y directions is at the same time. The width reaches the maximum value d _x-max and d _y-max ; at the same time, the spatial interference fringe decoupling algorithm is performed on the spatial interference fringes, and the initial values θ _X0 and θ _Y0 of the horizontal inclination angles in the X and Y directions are recorded;

Step 5, vertical laser pointing monitoring and real-time correction: perform spatial interference fringe decoupling algorithm on the spatial interference fringes, measure the angle results θ _X and θ _Y in real time, then the vertical laser relative to the gravitational direction in the X and Y directions. The angle deviations are respectively θ′ _X = θ _X - θ _X0 and θ _Y ′ = θ _Y - θ _Y0 ; at the same time, the signal processing card performs closed-loop feedback control on the attitude of the two-dimensional precision angle turntable according to the measured angle deviation, so that θ′ _X and θ _Y ′ are both zero.

The spatial interference fringe decoupling algorithm of the , which traces the angle measurement to the laser wavelength, includes:

Step 1: Convert the spatial interference fringes into a two-dimensional grayscale matrix, perform a two-dimensional discrete Fourier transform based on butterfly operation on the matrix, obtain the frequency space matrix of the spatial interference fringes, and calculate in the amplitude space of the spectrum of the spatial interference fringes. its different spatial frequency components;

Step 2: Obtain the maximum amplitude point and its corresponding position in the frequency space matrix in the amplitude space of the spatial interference fringe spectrum, and perform two-dimensional curve peak fitting using the amplitude information of the maximum amplitude point and the adjacent matrix points. , get the exact frequency coordinates after fitting;

Step 3, the angle measurement values θ _X and θ _Y have a linear relationship with the spatial frequency of the spatial interference fringes. According to the X-direction and Y-direction components of the precise frequency coordinates obtained by fitting, X can be obtained according to formula 1 and formula 2 respectively. Horizontal inclination angles θ _X and θ _Y to the Y direction.

In the formula, f _X and f _Y are the X- and Y-direction components of the spatial interference fringe frequency, respectively, λ is the laser wavelength, and n _liquid is the liquid refractive index. Since the liquid level is always perpendicular to the direction of gravity, this method can calculate and monitor the change of the laser pointing relative to the direction of gravity in real time.

The invention also provides a method for a vertical laser pointing correction device based on interference fringe decoupling, which utilizes the reflection and refraction effects of the liquid on the laser, takes the horizontal plane as the reference plane, and uses the spatial interference spot to direct the beam to the source of gravity. Using the slope reflection at the bottom of the liquid container, the beam inclination angle is converted into the spatial interference fringes of the linearly polarized laser, and by calculating the frequency of the spatial interference fringes in the X and Y directions, the angular deviation of the beam pointing relative to the direction of gravity is accurately measured; At the same time, the contrast of the interference signal and the signal-to-noise ratio are guaranteed by the conversion of the laser polarization state and the matching of the reflectivity. Finally, the precise real-time correction of the vertical laser pointing is realized by feedback control of the attitude of the vertical laser generator module. The vertical laser pointing correction device of the present invention is completely based on the principle of laser interference measurement, has high measurement resolution, and the angle measurement result can be directly traced to the laser wavelength, which meets the requirements of high-end equipment for ultra-precise vertical laser pointing. In addition, the integrated sensing module of the device of the present invention is convenient for disassembly and repeated installation, which is convenient for reuse in multiple sets of devices, and saves costs.

The above-mentioned embodiments are only to describe the preferred modes of the present invention, but not to limit the scope of the present invention. Without departing from the design spirit of the present invention, those of ordinary skill in the art can make various modifications to the technical solutions of the present invention. Variations and improvements should fall within the protection scope determined by the claims of the present invention.

Claims (10)

1. a vertical laser pointing correction device based on interference fringe decoupling, is characterized in that, comprises: a vertical laser generating module for generating a vertical laser signal and fine-tuning the direction of the vertical laser signal; an integrated sensing module, connected to the vertical laser generating module, for receiving the vertical laser signal, and generating a spatial interference image based on the vertical laser signal; A signal processing module, connected with the integrated sensing module, is used to perform high-precision decoupling operation on the spatial interference image, and obtain the angle deviation result of the vertical laser relative to the direction of gravity. According to the angle deviation result, realize Real-time correction of vertical laser pointing. 2. The vertical laser pointing correction device based on interference fringe decoupling according to claim 1, characterized in that, The vertical laser generation module includes a single-frequency laser, a single-mode polarization-maintaining fiber, a fiber collimator, a pentagonal prism, an integrated light source base, and a two-dimensional precision angle turntable; The single-frequency laser is used to provide a frequency-stabilized laser signal; The single-mode polarization-maintaining fiber is connected to the single-frequency laser, and is used for conducting the frequency-stabilized laser signal to the fiber collimator; The fiber collimator is connected to the single-mode polarization-maintaining fiber, and is used for receiving the frequency-stabilized laser signal and outputting the collimated laser; The pentagonal prism is used for receiving the collimated laser light and outputting a vertical laser signal; The integrated light source base is used for fixing the optical fiber collimator and the pentagonal prism; The two-dimensional precision angle turntable is used for placing the integrated sensing base and the integrated light source base. 3. The vertical laser pointing correction device based on interference fringe decoupling according to claim 1, characterized in that, The integrated sensing module includes an integrated sensing base, a beam splitting corner prism, a beam splitter, a reflector, a polarizing beam splitter, a quarter wave plate, a liquid container unit, a liquid unit, a micro-corner array, and an image sensor. ; The integrated sensing base is used to fix the beam splitter cube prism, beam splitter, reflector, polarized beam splitter, quarter wave plate, liquid container unit, liquid unit, and image sensor; the beam splitting corner prism is used for transmitting the vertical laser signal and reflecting part of the vertical laser signal to the first beam splitter; The spectroscope is used for dividing the vertical laser signal into transmitted light and reflected light; the reflecting mirror is used for reflecting the reflected light to the polarizing beam splitter; The polarizing beam splitter is used to transmit the transmitted light and reflected light whose polarization state is P to the quarter-wave plate; and is used to reflect the first liquid surface refracted light and the first liquid surface reflection whose polarization state is S light, the second liquid surface refracted light, and the second liquid surface reflected light to obtain the first signal light, the second signal light, the third signal light, and the fourth signal light and send them to the image sensor; The quarter wave plate is used to transmit the transmitted light and reflected light, and convert it into circularly polarized light; it is used to refract the first liquid surface refracted light, the first liquid surface reflected light, and the second liquid surface refracted light The polarization state of the light and the light reflected from the second liquid surface becomes S; The liquid container unit is used to place the liquid in the liquid unit; it is used to reflect the second liquid surface refracted light on the bottom surface to a quarter-wave plate; The liquid unit is used for dividing the transmitted light and reflected light into circularly polarized light through the liquid surface into first liquid surface refracted light, first liquid surface reflected light, second liquid surface refracted light, and second liquid surface refracted light. Surface reflected light; used to reflect the first liquid surface reflected light and the second liquid surface reflected light to a quarter wave plate; The micro-pyramid array is arranged at the bottom of the liquid container unit, and is used for reflecting the first liquid surface refracted light to a quarter-wave plate; The image sensor is used to detect the spatial interference light spot formed by the interference of the first signal light and the second signal light; and used to detect the spatial interference fringes formed by the interference of the third signal light and the fourth signal light. 4. The vertical laser pointing correction device based on interference fringe decoupling according to claim 3, characterized in that, The spatial interference light spot and the spatial interference fringes do not overlap in space. 5. The vertical laser pointing correction device based on interference fringe decoupling according to claim 1, wherein, The signal processing module includes a host computer and a signal processing card; The signal processing card is used to perform high-precision decoupling operation on the interference signal through the spatial interference fringe decoupling algorithm, and send a feedback control signal to the two-dimensional precision angle turntable according to the measurement result to correct the vertical laser pointing and trace the source to the direction of gravity. , and upload the operation result to the upper computer; The upper computer is used for receiving, displaying and storing the measurement results of the vertical laser pointing correction. 6. A vertical laser pointing correction method based on interference fringe decoupling is characterized in that, comprising, Obtain a vertical laser signal through a vertical laser generating module, transmit the vertical laser signal to an integrated sensing module, and generate a spatial interference image based on the integrated sensing module; The spatial interference image is input into the signal processing module for high-precision decoupling operation to obtain the angular deviation result of the vertical laser relative to the gravitational direction, and real-time correction of the vertical laser pointing is realized according to the angular deviation result. 7 . The vertical laser pointing correction method based on interference fringe decoupling according to claim 6 , wherein a vertical laser signal is obtained through a vertical laser generating module, and the vertical laser signal is transmitted to the integrated transmission system. 8 . The process of the sense module includes, A frequency-stabilized laser signal is generated by a single-frequency laser, and the frequency-stabilized laser signal is conducted to a fiber collimator through a single-mode polarization-maintaining fiber; the fiber collimator outputs a collimated laser, which is obtained through a pentagonal prism After the vertical laser signal is transmitted, the vertical laser signal is transmitted to the integrated sensing module. 8. The vertical laser pointing correction method based on interference fringe decoupling according to claim 6, wherein the process of generating a spatial interference image based on the integrated sensing module comprises: The vertical laser signal is reflected by the beam splitter corner prism and then returns in the original direction, and is divided into transmitted light and reflected light by the beam splitter; The transmitted light is transmitted through a polarizing beam splitter and a quarter-wave plate to obtain circularly polarized light; the circularly polarized light is divided into the first liquid surface refracted light and the first liquid surface reflected light on the surface of the liquid unit; The reflected light is reflected by the mirror, and then transmitted through a polarizing beam splitter and a quarter-wave plate to obtain circularly polarized light; the circularly polarized light is divided into a second liquid surface refracted light and a second liquid surface refracted light on the surface of the liquid unit. liquid surface reflected light; The first liquid surface refracted light is reflected by the micro-pyramid array at the bottom of the liquid container unit and returns to the original path, and the polarization state becomes S after passing through the quarter-wave plate in the reverse direction, and then becomes the first after being reflected by the polarization beam splitter. The signal light is directed to the image sensor; The first liquid surface reflected light and the second liquid surface reflected light are reflected by the liquid, and the polarization state changes to S after passing through the quarter-wave plate in the reverse direction, and then becomes the second signal light and the fourth signal light after being reflected by the polarization beam splitter. The signal light is directed to the image sensor; The second liquid surface refracted light is reflected by the bottom surface of the liquid container, and the polarization state changes to S after passing through the quarter-wave plate in the reverse direction, and then becomes the third signal light after being reflected by the polarization beam splitter and is directed to the image sensor; The first signal light and the second signal light interfere on the detection surface of the image sensor to obtain spatial interference light spots; the third signal light and the fourth signal light interfere on the detection surface of the image sensor to obtain spatial interference fringes; The spatial interference light spot and the spatial interference fringe do not overlap in space. 9. The vertical laser pointing correction method based on interference fringe decoupling according to claim 6, wherein the real-time correction process of the vertical laser pointing comprises: Send the spatial interference image to the signal processing card, and the signal processing card traces the vertical laser signal to the absolute gravity direction through the angle modulation of the two-dimensional precision angle turntable and the Gaussian fitting of the spatial interference light spot, Then perform the interference fringe decoupling algorithm on the spatial interference fringes to realize the precise measurement of the vertical laser pointing, and finally send a feedback control signal to the two-dimensional precision angle turntable according to the measurement results to realize the real-time correction of the vertical laser pointing, and upload the measurement results at the same time. to the host computer. 10 . The vertical laser pointing correction method based on interference fringe decoupling according to claim 9 , wherein the process of performing the interference image decoupling algorithm on the spatial interference image comprises: 10 . Sending the spatial interference image to a signal processing card, and the signal processing card performs a high-precision decoupling operation on the wavefront spatial interference image through an interference image decoupling algorithm, including: Convert the spatial interference fringes into a two-dimensional grayscale matrix, perform a two-dimensional discrete Fourier transform based on butterfly operation on the two-dimensional grayscale matrix, and obtain the frequency space matrix of the spatial interference fringes. The amplitude space of , calculates different spatial frequency components; Based on the amplitude space of the spatial interference fringe spectrum, the maximum amplitude point and its corresponding position in the frequency space matrix are obtained, and the peak value of the two-dimensional curve is fitted by using the amplitude information of the maximum amplitude point and the adjacent matrix points to obtain The exact frequency coordinates after fitting; According to the X-direction and Y-direction components of the accurate frequency coordinates obtained by fitting, the horizontal inclination angles of the X-direction and Y-direction are obtained respectively according to the formula that the angle measurement value is linearly related to the spatial frequency of the spatial interference fringes.

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