High-precision semi-automatic assembling and adjusting method for laser radar transmitting and receiving module

Abstract

The invention discloses a high-precision semi-automatic assembling and adjusting method for a laser radar transmitting and receiving module. Each optical element of the MEMS laser radar transmitting and receiving module can be quickly and conveniently assembled and adjusted by using simple measuring equipment such as an optical reticle, an optical guide rail, a semi-transparent and semi-reflecting mirror, an infrared camera and a phase shift interferometer. The installation positions of optical lenses of the transmitting module and the receiving module are detected in real time by using a phase shift interferometer and a computer-aided adjustment method; an optical reticle on an optical guide rail is automatically moved, and an infrared camera is adopted to detect the contour of a light spot, so that the installed and adjusted lens can be accurately adjusted in real time to ensure that the collimation precision of a transmitting module meets the requirement; after the transmit-receive module is installed, the reflection calibration plate on the optical guide rail is moved to calibrate the reflection intensity of the MEMS laser radar transmit-receive module. According to the method, semi-automation of an MEMS laser radar transmitting and receiving module assembling and adjusting process can be realized, and the assembling and adjusting efficiency of the MEMS laser radar is improved while the assembling and adjusting precision of each component is effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a high-precision semi-automatic assembly and adjustment method for a laser radar transmitting and receiving module. Background Art

[0002] At present, LiDAR has been widely used in the field of unmanned driving. The mainstream LiDAR can be divided into mechanical, semi-solid and solid types based on the scanning method. Mechanical LiDAR has a complex mechanical structure, low reliability due to wear of rotating parts, and high cost, while solid-state LiDAR technology is not mature enough. Based on the above problems, semi-solid LiDAR, as a mainstream LiDAR on the market, has become the preferred front-end solution for various automobile manufacturers.

[0003] Among semi-solid-state laser radars, there are mainly three types of products: MEMS laser radar, rotating mirror laser radar, and prism laser radar. Among them, MEMS laser radar has a very small size of MEMS mirror, which greatly reduces the volume and weight of the entire laser radar, making it easy to integrate into various devices, especially for application scenarios with limited space, such as self-driving cars. At the same time, the internal mechanical structure of MEMS laser radar is greatly simplified, reducing wear and failure caused by mechanical movement and improving reliability. In addition, the MEMS mirror moves very fast, which can achieve fast scanning and improve the response speed and data acquisition efficiency of the laser radar. Therefore, MEMS laser radar is one of the most popular mainstream laser radars at present. In MEMS laser radar, due to its compact structure and small space, the assembly and adjustment accuracy of the transmitting and receiving units is one of the key factors affecting the overall performance indicators of the laser radar.

[0004] MEMS LiDAR transmitting and receiving modules usually use coaxial transceiver optical systems, and the integrated design can further reduce the product size to meet vehicle-mounted requirements, such as Figure 1 As shown. This also means that MEMS LiDAR requires extremely high precision in the assembly and adjustment of optical components, and has high requirements for factory debugging. Inefficient debugging and assembly is the main bottleneck for releasing production capacity and reducing costs. At present, there are few assembly and adjustment methods for vehicle-mounted autonomous driving MEMS LiDARs, and assembly and adjustment methods based on the integrated receiving and transmitting modules of MEMS LiDARs have not been reported. In addition, how to quickly complete the integrated assembly and calibration of receiving and transmitting modules with high efficiency and without significantly increasing economic costs is one of the problems that need to be solved in the production of MEMS LiDARs. Summary of the invention

[0005] In response to at least one of the above problems, the present invention provides a high-precision semi-automatic assembly and adjustment method for a laser radar transmitting and receiving module. The method adopts a computer-aided assembly and adjustment method and utilizes automated guide rail control to monitor the state of the light spot in real time, thereby realizing semi-automation of the entire assembly and adjustment process of the MEMS laser radar transmitting and receiving module, thereby effectively ensuring the assembly and adjustment accuracy of each component while improving the assembly and adjustment efficiency of the MEMS laser radar.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-precision semi-automatic assembly and adjustment method for a laser radar transmitting and receiving module comprises the following steps:

[0008] Step S1: installing the transmitting module, and measuring the wavefront aberration of the transmitting module by using a phase-shifting interferometer, and correcting the position deviation of the fast-axis collimator and the slow-axis collimator of the transmitting module by a computer-aided adjustment method;

[0009] Step S2: Install the transmitting module on the fixture of the electric optical guide rail mounting base, install the semi-transparent and semi-reflective mirror through the optical fixture, and place an infrared camera in the reflection direction of the semi-transparent and semi-reflective mirror;

[0010] Step S3: Process the laser spot collected by the infrared camera through a computer, calculate the length of the spot in the x and y directions, draw and fit the collected lengths of the spot in the x and y directions into a straight line, calculate the fast axis and slow axis divergence angles of the spot, and check whether the spot divergence angle meets the system design requirements;

[0011] Step S4: Install the semi-transparent and semi-reflective mirror of the transmitting and receiving integrated module between the semi-transparent and semi-reflective mirror and the transmitting module, and install the plane reflective mirror, and adjust the position of the semi-transparent and semi-reflective mirror so that the position of the return light spot is approximately located at the center of the mirror surface of the plane reflective mirror;

[0012] Step S5: using an image centroid detection algorithm to detect the centroid position of the light spot on the plane reflector, so that the mirror centroid coordinates of the plane reflector and the centroid of the light spot on the mirror surface of the plane reflector coincide with each other;

[0013] Step S6: installing the receiving module, replacing the receiving detector with a standard laser light source, and measuring the wavefront aberration of the receiving module using a phase-shifting interferometer, and correcting the position deviation of the receiving focusing lens I and the receiving focusing lens II of the receiving module by a computer-aided adjustment method;

[0014] Step S7: replacing the standard laser light source in the receiving module with a receiving detector, and fine-tuning the receiving detector to make the detector receive the strongest signal;

[0015] Step S8: Fix the transmitting and receiving integrated module, return the position of the cross-grain plate on the electric optical rail to zero, and gradually move the cross-grain plate on the electric optical rail to record the signal strength of the receiving detector corresponding to the distance at this time. The intensity calibration of the transmitting and receiving integrated module is completed, and the installation and calibration of the transmitting and receiving integrated module are completed.

[0016] As a preferred embodiment of the above scheme, in step S1, the computer-aided adjustment method specifically includes:

[0017] An optical model of the emission module to be installed and adjusted is established in the optical design software, and the optical elements in the optical model are numbered in sequence along the optical path direction; first, a slow-axis collimator is not introduced, and an optical system is composed of a laser diode and a fast-axis collimator, the image plane position of the fast-axis collimator is selected, and the ideal wavefront aberration F0n of the optical system is obtained through simulation analysis; a position deviation Δx0s not greater than the rough adjustment accuracy is introduced into the fast-axis collimator in the optical subsystem, and the optical system after the introduction of the simulated position deviation Δx0s is simulated and analyzed using the optical design software to obtain the simulated wavefront aberration F0s of the image plane in the optical system; according to the simulated position deviation Δx0s, the ideal wavefront aberration F0n and the simulated wavefront aberration F0s, the sensitivity matrix corresponding to the optical system is solved by the sensitivity matrix formula, and the sensitivity matrix A0 of the fast-axis collimator is extracted;

[0018] A0=(F0s-F0n) / Δx0s;

[0019] According to the serial numbering sequence of the optical subsystems, the sensitivity matrix A0 of the fast-axis collimator is used to perform tolerance analysis on the optical system. The object plane of the optical system is used as a reference, and the fast-axis collimator in the optical system is roughly adjusted according to the tolerance analysis results. The actual wavefront aberration F0 of the image plane of the optical system after the rough adjustment is measured by a phase-shifting interferometer. The position deviation Δx0 of the fast-axis collimator and the deviation type are obtained by inversely solving the sensitivity matrix A0, the actual wavefront aberration F0 and the ideal wavefront aberration F0n.

[0020] Δx0=(F0-F0n) / A0

[0021] The position of the fast-axis collimator in the optical system is adjusted according to the calculated position deviation Δx0 of the fast-axis collimator and the deviation type; the actual wavefront aberration F0 of the image plane of the optical system is measured again using a phase-shifting interferometer, and it is determined whether the deviation between the actual wavefront aberration F0 and the ideal wavefront aberration F0n is within an allowable range. If so, the fast-axis collimator is installed and adjusted.

[0022] As a preferred embodiment of the above scheme, step S2 specifically includes: with the help of an optical guide rail base and an optical clamp, the assembled and adjusted transmitting module is installed on the optical guide rail base as a whole using the optical clamp, and the optical axis of the transmitting module is ensured to be as horizontal as possible; a semi-transparent and semi-reflective mirror is installed between the transmitting module and the electric optical guide cross-grain plate through an optical clamp; an infrared camera is placed in the reflection direction of the semi-transparent and semi-reflective mirror, and the focal length of the infrared camera is adjusted so that the reflected light spot can be clearly imaged in the middle of the field of view of the infrared camera.

[0023] As a preferred embodiment of the above scheme, step S3 specifically includes: using a computer to collect the laser spot received by the infrared camera, and calculating the x and y direction radii of the spot through spot profile extraction and fitting algorithm, which are x1 and y1 respectively, gradually moving the electric optical guide rail, recording the x and y direction radii of the laser spot at the nth position, which are xn and yn respectively, drawing the x direction radii x1 to xn corresponding to the above 1 to n positions into a curve, and calculating the slope of the straight line by a straight line fitting method, which is the slow axis divergence angle, drawing the y direction radii y1 to yn corresponding to the above 1 to n positions into a curve, and calculating the slope of the straight line by a straight line fitting method, which is the fast axis divergence angle, and judging whether the divergence angle meets the design indicators.

[0024] As a preferred embodiment of the above scheme, the spot contour extraction and fitting detection algorithm program is developed based on the OPENCV library, including camera video acquisition, image extraction, filtering, edge detection, contour extraction, and contour fitting steps.

[0025] As a preferred embodiment of the above scheme, step S4 specifically includes: installing a semi-transparent and semi-reflective mirror and a plane reflector in sequence, and using a 905nm infrared sensitive film at the receiving detector position to observe whether there is a return light spot. If so, the position of the returned light spot is roughly located at the center of the mirror surface of the plane reflector, and the installation and adjustment is completed. If not, fine-tune the semi-transparent and semi-reflective mirror and the plane reflector until there is a return light spot on the infrared sensitive film.

[0026] As a preferred embodiment of the above scheme, step S5 specifically includes: using OPENCV to develop an image centroid detection algorithm, detecting the centroid coordinates of the plane reflector and the centroid coordinates of the light spot, and when the coordinates of the two coincide, the plane reflector is installed and adjusted, otherwise, fine-tuning the plane reflector and the semi-transparent and semi-reflective mirror until the centroid coordinates of the two coincide; wherein the image centroid detection algorithm includes camera video acquisition, image extraction, filtering, contour extraction, and coordinate detection steps.

[0027] As a preferred embodiment of the above scheme, step S6 specifically includes: using the computer-aided adjustment method in step S1, an optical subsystem 1 is composed of a standard laser light source and a receiving focusing lens I, and the adjustment of the receiving focusing lens I is completed; and the optical subsystem is added to the receiving focusing lens II to form an optical subsystem 2, and the adjustment of the receiving focusing lens II is completed, and the standard laser light source is removed to complete the adjustment of the focusing lens part of the receiving module.

[0028] As a preferred embodiment of the above scheme, step S7 specifically includes: replacing the standard laser light source in the receiving module with a receiving detector, and assembling the receiving module into a transmitting and receiving integrated module, issuing motion control instructions to move the cross-grained plate on the optical electric guide rail, and fine-tuning the receiving detector forward and backward. If the receiving signal of the receiving detector is weakened, the receiving detector is restored to the position where the receiving signal of the receiving detector is the strongest, and the installation and adjustment of the receiving detector is completed.

[0029] As a preferred embodiment of the above scheme, step S8 specifically includes: fixing the installed transmitting and receiving integrated module, fine-tuning the transmitting and receiving integrated module, observing with an infrared camera so that the light spot can be imaged in the middle of the cross-hair plate, removing the semi-transparent and semi-reflective mirror, gradually moving the cross-hair plate on the optical electric guide rail, and recording the distances at different positions and the signal strength of the receiver detected at this time, until the optical guide rail is at the farthest position, thereby completing the calibration of the transmitting and receiving integrated module.

[0030] Due to the above structure, the beneficial effects of the present invention are:

[0031] The present invention is aimed at the MEMS laser radar transmitting and receiving module, and can quickly and conveniently assemble and adjust the various optical elements of the MEMS laser radar transmitting and receiving module by using simple measuring equipment such as an optical graticule, an optical guide rail, a semi-transparent and semi-reflective mirror, an infrared camera and a phase-shifting interferometer. The phase-shifting interferometer is used to adopt a computer-aided assembly method to detect the installation position of the optical lenses of the transmitting module and the receiving module in real time; by automatically moving the optical graticule on the optical guide rail, the infrared camera is used to detect the spot size, and the assembled lenses can be accurately adjusted in real time to ensure that the collimation accuracy of the transmitting module meets the requirements; after the transceiver module is installed, the reflection intensity of the MEMS laser radar transmitting and receiving module can be calibrated by moving the reflection calibration plate on the optical guide rail. This method adopts a computer-aided assembly method and uses an automated guide rail to control the real-time monitoring of the spot state, so as to realize the semi-automation of the entire assembly process of the MEMS laser radar transmitting and receiving module, and effectively ensure the assembly accuracy of each component while improving the assembly efficiency of the MEMS laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below.

[0033] Figure 1 This is a schematic diagram of the structure of the laser radar transmitting and receiving module of the present invention;

[0034] Figure 2 It is a work flow chart of the present invention;

[0035] Figure 3 This is a schematic diagram of the assembly and adjustment structure of the laser radar transmitting module of the present invention;

[0036] Figure 4 This is a schematic diagram of the alignment accuracy detection of the laser radar transmitting module of the present invention;

[0037] Figure 5 It is a schematic diagram of the assembly and adjustment structure of the semi-transparent and semi-reflective mirror of the laser radar of the present invention;

[0038] Figure 6 It is a schematic diagram of the assembly and adjustment structure of the laser radar plane reflector of the present invention;

[0039] Figure 7 This is a schematic diagram of the assembly and adjustment structure of the laser radar receiving module of the present invention;

[0040] Figure 8 This is a schematic diagram of the calibration and adjustment structure of the laser radar transmitting and receiving module of the present invention;

[0041] In the figure, the corresponding relationship between each component and the reference numeral is as follows:

[0042] 1. Laser emitting diode, 2. Fast axis collimator, 3. Fast axis collimator, 4. Transmitting module, 5. Semi-transparent and semi-reflective mirror 1, 6. Receiving detector, 7. Receiving focusing lens I, 8. Receiving module, 9. Receiving focusing lens II, 10. Plane reflector, 11. Transmitting and receiving integrated module, 12. Target plate, 13. Infrared camera, 14. Semi-transparent and semi-reflective mirror 2, 15. Cross-section plate, 16. Electric optical guide, 17. Phase-shifting interferometer, 18. Standard laser light source. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0044] like Figures 2 to 8 As shown, this embodiment provides a high-precision semi-automatic assembly and adjustment method for a laser radar transmitting and receiving module, comprising the following steps:

[0045] Step S1: Install the transmitting module 4, and use the phase-shifting interferometer 17 to measure the wavefront aberration of the transmitting module 4, and correct the position deviation of the fast-axis collimator 2 and the fast-axis collimator 3 of the transmitting module 4 by a computer-aided adjustment method. Specifically:

[0046] According to the sequential adjustment method, the emission module 4 is first adjusted, an optical model of the emission module 4 to be adjusted is established in the optical design software, and the optical elements in the optical model are numbered in sequence along the optical path direction; first, the slow axis collimator 3 is not introduced, and the optical system is composed of the laser diode 1 and the fast axis collimator 2, the image plane position of the fast axis collimator 2 is selected, and the ideal wavefront aberration F0n of the optical system is obtained by simulation analysis;: a position deviation Δx not greater than the rough adjustment accuracy is introduced to the fast axis collimator 2 in the optical subsystem 0s , using optical design software to introduce the simulated position deviation Δx 0s The optical system is simulated and analyzed to obtain the simulated wavefront aberration F0s of the image plane in the optical system; according to the simulated position deviation Δx 0s , ideal wavefront aberration F0n and simulated wavefront aberration F0s, using a sensitivity matrix formula to solve the sensitivity matrix corresponding to the optical system and extract the sensitivity matrix A0 of the fast axis collimator;

[0047] A0=(F0s-F0n) / Δx 0s ;

[0048] According to the numbering sequence of the optical subsystems, the optical system is subjected to tolerance analysis using the sensitivity matrix A0 of the fast-axis collimator 2, and the object plane of the optical system is used as a reference, and the fast-axis collimator 2 in the optical system is roughly adjusted according to the tolerance analysis result; the actual wavefront aberration F0 of the image plane of the optical system after the rough adjustment is measured using a phase-shifting interferometer 17; the position deviation Δx0 of the fast-axis collimator 2 and the deviation type are obtained by inversely solving the sensitivity matrix A0, the actual wavefront aberration F0 and the ideal wavefront aberration F0n;

[0049] Δx0=(F0-F0n) / A0

[0050] The position of the fast-axis collimator 2 in the optical system is adjusted according to the calculated position deviation Δx0 and deviation type of the fast-axis collimator 2; the actual wavefront aberration F0 of the image plane of the optical system is measured again using the phase-shifting interferometer 17, and it is determined whether the deviation between the actual wavefront aberration F0 and the ideal wavefront aberration F0n is within the allowable range. If so, the installation and adjustment of the fast-axis collimator 2 is completed.

[0051] In the above optical system, a slow axis collimator 3 is added, and the slow axis collimator 3 is adjusted according to the above computer-aided adjustment method.

[0052] Step S2: Install the transmitting module 4 on the fixture of the electric optical rail 16 mounting base, install the semi-transparent and semi-reflective mirror 14 through the optical fixture, and place the infrared camera 13 in the reflection direction of the semi-transparent and semi-reflective mirror 14. The image resolution of the infrared camera is 1920*1080. Specifically:

[0053] The transmitting module 4 is installed on the base of the optical guide rail 16 by using an optical clamp to ensure that the optical axis of the transmitting module 4 is as horizontal as possible; the semi-transparent and semi-reflective mirror 14 is installed between the transmitting module 4 and the cross-grained plate 15 of the electric optical guide rail 16 by using an optical clamp; the infrared camera 13 is placed in the reflecting direction of the semi-transparent and semi-reflective mirror 14, and the focal length of the infrared camera 13 is adjusted so that the reflected light spot can be clearly imaged in the middle of the field of view of the infrared camera 13.

[0054] Step S3: Process the laser spot collected by the infrared camera 13 through a computer, calculate the length of the spot in the x and y directions, draw and fit the collected length of the spot in the x and y directions into a straight line, calculate the fast axis and slow axis divergence angles of the spot, and check whether the spot divergence angle meets the system design requirements. Specifically:

[0055] The computer is used to collect the laser spot received by the infrared camera 13, and the x and y direction radii of the spot are calculated by extracting and fitting the spot profile, which are x1 and y1 respectively. The electric optical guide rail 16 is moved step by step to record the x and y direction radii of the laser spot at the 10th position, which are x and y1 respectively. 10 ,y 10 . The x-direction radius x1 to x10 corresponding to the above positions 1 to 10 10 Draw a curve, and calculate the slope of the line by straight line fitting, which is the slow axis divergence angle. 10 Draw a curve and calculate the slope of the line by straight line fitting, which is the fast axis divergence angle. Determine whether the divergence angle meets the design specifications.

[0056] Among them, the spot contour extraction and fitting algorithm program is developed based on the OPENCV library, including camera video acquisition, image extraction, filtering, edge detection, contour extraction, and contour fitting steps.

[0057] Step S4: Install the semi-transparent mirror 5 of the transmitting and receiving integrated module 11 between the semi-transparent mirror 14 and the transmitting module 4, and install the plane reflector 10. Adjust the position of the semi-transparent mirror 5 so that the position of the return light spot is approximately located at the center of the mirror surface of the plane reflector 5. Specifically:

[0058] Install the semi-transparent and semi-reflective mirrors and the plane reflector in sequence, and use the 905nm infrared photosensitive film at the receiving detector position to observe whether there is a return light spot. If there is, the position of the return light spot is roughly located at the center of the mirror surface of the plane reflector, and the installation and adjustment is completed. If not, fine-tune the semi-transparent and semi-reflective mirrors and the plane reflector until there is a return light spot on the infrared photosensitive film.

[0059] Step S5: using an image centroid detection algorithm to detect the centroid position of the light spot on the plane reflector 5 , so that the mirror centroid coordinates of the plane reflector 5 and the centroid of the light spot on the mirror surface of the plane reflector 5 coincide with each other.

[0060] Specific:

[0061] The image centroid detection algorithm is used to detect the centroid coordinates of the plane reflector 10 and the spot centroid coordinates. When the two coordinates coincide, the plane reflector 10 is installed. The image centroid detection algorithm program is developed based on the OpenCV library, including camera video acquisition, image extraction, filtering, contour extraction, centroid detection and other steps.

[0062] Step S6: Install the receiving module 8 and replace the receiving detector 6 with a standard laser light source 18. Use a phase-shifting interferometer to measure the wavefront aberration of the receiving module 8, and use a computer-aided adjustment method to correct the position deviation of the receiving focusing lens I7 and the receiving focusing lens II9 of the receiving module 8. Specifically:

[0063] By using the computer-aided adjustment method in step S1, an optical subsystem 1 is formed by a standard laser light source 18 and a receiving focusing lens I7, and the adjustment of the receiving focusing lens I7 is completed; and the optical subsystem is added with a receiving focusing lens II9 to form an optical subsystem 2, and the adjustment of the receiving focusing lens II9 is ​​completed. The standard laser light source 18 is removed, and the adjustment of the focusing lens part of the receiving module 8 is completed.

[0064] Step S7: Replace the standard laser light source 18 in the receiving module 8 with the receiving detector 6, and fine-tune the receiving detector 6 so that the detector 6 receives the strongest signal. Specifically:

[0065] Replace the standard laser light source 18 in the receiving module 8 with the receiving detector 6, and install the receiving module 8 into the transmitting and receiving integrated module 11, move the cross-grain plate 15 on the optical electric guide rail 16, and fine-tune the receiving detector 6 back and forth. If the receiving signal of the receiving detector 6 is weakened, restore the receiving detector 6 to the position where the receiving signal of the receiving detector 6 is the strongest.

[0066] Step S8: Fix the transmitting and receiving integrated module 11, return the position of the cross-grained plate 15 on the electric optical guide rail 16 to zero, and gradually move the cross-grained plate 15 on the optical electric guide rail 16 to record the signal strength of the receiving detector 6 corresponding to the distance at this time, and then complete the intensity calibration of the transmitting and receiving integrated module 11, and the installation and calibration of the transmitting and receiving integrated module 11 are completed. Specifically:

[0067] Fix the transmitting and receiving integrated module 11, fine-tune the transmitting and receiving integrated module 11, observe with the infrared camera 13, make the light spot image in the middle of the cross-reticle plate 15, remove the semi-transparent and semi-reflective mirror 14, move the cross-reticle plate 15 step by step, and record the distances at different positions and the signal strength of the detection receiver 6 at this time, until the cross-reticle plate 15 is located at the farthest position of the optical guide rail 16, and complete the calibration of the transmitting and receiving integrated module 11.

[0068] This embodiment is aimed at the MEMS laser radar transmitting and receiving module, and the various optical components of the MEMS laser radar transmitting and receiving module can be quickly and conveniently assembled and adjusted by using simple measuring equipment such as optical graticules, optical guides, semi-transparent and semi-reflective mirrors, infrared cameras and phase-shifting interferometers. The computer-aided assembly method is used to monitor the installation position of the optical lenses of the transmitting module and the receiving module by using a phase-shifting interferometer; by automatically moving the optical graticule on the optical guide and using an infrared camera to detect the light spot profile, the assembled lenses can be accurately adjusted to ensure that the collimation accuracy of the transmitting module meets the requirements; after the transceiver module is installed, the reflection intensity of the MEMS laser radar transmitting and receiving module can be calibrated by moving the reflection calibration plate on the optical guide. This method uses a computer-aided assembly method and uses an automated guide rail to control the real-time monitoring of the light spot state, so as to achieve semi-automation of the entire assembly process of the MEMS laser radar transmitting and receiving module, effectively ensuring the assembly accuracy of each component while improving the assembly efficiency of the MEMS laser radar.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-precision semi-automatic adjustment method for a laser radar transmitting and receiving module, characterized in that: The following steps are involved: Step S1: installing the transmitting module, and measuring the wavefront aberration of the transmitting module by using a phase-shifting interferometer, and correcting the position deviation of the fast-axis collimator and the slow-axis collimator of the transmitting module by a computer-aided adjustment method; Step S2: Install the transmitting module on the fixture of the electric optical guide rail mounting base, install the semi-transparent and semi-reflective mirror through the optical fixture, and place an infrared camera in the reflection direction of the semi-transparent and semi-reflective mirror; Step S3: Process the laser spot collected by the infrared camera through a computer, calculate the length of the spot in the x and y directions, draw and fit the collected lengths of the spot in the x and y directions into a straight line, calculate the fast axis and slow axis divergence angles of the spot, and check whether the spot divergence angle meets the system design requirements; Step S4: Install the semi-transparent and semi-reflective mirror of the transmitting and receiving integrated module between the semi-transparent and semi-reflective mirror and the transmitting module, and install the plane reflective mirror, and adjust the position of the semi-transparent and semi-reflective mirror so that the position of the return light spot is approximately located at the center of the mirror surface of the plane reflective mirror; Step S5: using an image centroid detection algorithm to detect the centroid position of the light spot on the plane reflector, so that the mirror centroid coordinates of the plane reflector and the centroid of the light spot on the mirror surface of the plane reflector coincide with each other; Step S6: installing the receiving module, replacing the receiving detector with a standard laser light source, and measuring the wavefront aberration of the receiving module using a phase-shifting interferometer, and correcting the position deviation of the receiving focusing lens I and the receiving focusing lens II of the receiving module by a computer-aided adjustment method; Step S7: replacing the standard laser light source in the receiving module with a receiving detector, and fine-tuning the receiving detector to make the detector receive the strongest signal; Step S8: Fix the transmitting and receiving integrated module, return the position of the cross-grain plate on the electric optical rail to zero, and gradually move the cross-grain plate on the electric optical rail to record the signal strength of the receiving detector corresponding to the distance at this time. The intensity calibration of the transmitting and receiving integrated module is completed, and the installation and calibration of the transmitting and receiving integrated module are completed.

2. A high-precision semi-automatic adjustment method for a laser radar transmitting and receiving module according to claim 1, characterized in that: In step S1, the computer-aided assembly and adjustment method specifically includes: An optical model of the emission module to be installed and adjusted is established in the optical design software, and the optical elements in the optical model are numbered in sequence along the optical path direction; first, a slow-axis collimator is not introduced, and an optical system is composed of a laser diode and a fast-axis collimator, the image plane position of the fast-axis collimator is selected, and the ideal wavefront aberration F0n of the optical system is obtained through simulation analysis; a position deviation Δx0s not greater than the rough adjustment accuracy is introduced into the fast-axis collimator in the optical subsystem, and the optical system after the introduction of the simulated position deviation Δx0s is simulated and analyzed using the optical design software to obtain the simulated wavefront aberration F0s of the image plane in the optical system; according to the simulated position deviation Δx0s, the ideal wavefront aberration F0n and the simulated wavefront aberration F0s, the sensitivity matrix corresponding to the optical system is solved by the sensitivity matrix formula, and the sensitivity matrix A0 of the fast-axis collimator is extracted; A0=(F0s-F0n) / Δx0s; According to the serial numbering sequence of the optical subsystems, the sensitivity matrix A0 of the fast-axis collimator is used to perform tolerance analysis on the optical system. The object plane of the optical system is used as a reference, and the fast-axis collimator in the optical system is roughly adjusted according to the tolerance analysis results. The actual wavefront aberration F0 of the image plane of the optical system after the rough adjustment is measured by a phase-shifting interferometer. The position deviation Δx0 of the fast-axis collimator and the deviation type are obtained by inversely solving the sensitivity matrix A0, the actual wavefront aberration F0 and the ideal wavefront aberration F0n. Δx0=(F0-F0n) / A0 The position of the fast-axis collimator in the optical system is adjusted according to the calculated position deviation Δx0 of the fast-axis collimator and the deviation type; the actual wavefront aberration F0 of the image plane of the optical system is measured again using a phase-shifting interferometer, and it is determined whether the deviation between the actual wavefront aberration F0 and the ideal wavefront aberration F0n is within an allowable range. If so, the fast-axis collimator is installed and adjusted.

3. A high-precision semi-automatic adjustment method for a laser radar transmitting and receiving module according to claim 1, characterized in that: Step S2 specifically includes: with the help of an optical guide rail base and an optical clamp, the assembled and adjusted transmitting module is installed on the optical guide rail base as a whole using the optical clamp, and the optical axis of the transmitting module is ensured to be as horizontal as possible; between the transmitting module and the electric optical guide rail cross-cut plate, a semi-transparent and semi-reflective mirror is installed through an optical clamp; an infrared camera is placed in the reflection direction of the semi-transparent and semi-reflective mirror, and the focal length of the infrared camera is adjusted so that the reflected light spot can be clearly imaged in the middle of the infrared camera's field of view.

4. The high-precision semi-automatic adjustment method for a laser radar transmitting and receiving module according to claim 1 is characterized in that: Step S3 specifically includes: using a computer to collect the laser spot received by the infrared camera, and calculating the x and y direction radii of the spot through spot profile extraction and fitting algorithm, which are x1 and y1 respectively, gradually moving the electric optical guide rail, recording the x and y direction radii of the laser spot at the nth position, which are xn and yn respectively, plotting the x direction radii x1 to xn corresponding to the above 1 to n positions into a curve, and calculating the slope of the straight line by a straight line fitting method, which is the slow axis divergence angle, plotting the y direction radii y1 to yn corresponding to the above 1 to n positions into a curve, and calculating the slope of the straight line by a straight line fitting method, which is the fast axis divergence angle, and judging whether the divergence angle meets the design indicators.

5. A high-precision semi-automatic adjustment method for laser radar transmitting and receiving modules according to claim 4, characterized in that: The spot contour extraction and fitting detection algorithm program is developed based on the OPENCV library, including camera video acquisition, image extraction, filtering, edge detection, contour extraction, and contour fitting steps.

6. A high-precision semi-automatic adjustment method for laser radar transmitting and receiving modules according to claim 1, characterized in that: Step S4 specifically includes: installing the semi-transparent and semi-reflective mirror and the plane reflector in sequence, and using a 905nm infrared sensitive film at the receiving detector position to observe whether there is a return light spot. If there is, the position of the returned light spot is roughly located at the center of the mirror surface of the plane reflector, and the installation and adjustment is completed. If not, fine-tune the above-mentioned semi-transparent and semi-reflective mirror and the plane reflector until there is a return light spot on the infrared sensitive film.

7. A high-precision semi-automatic adjustment method for a laser radar transmitting and receiving module according to claim 1, characterized in that: Step S5 specifically includes: using OPENCV to develop an image centroid detection algorithm, detecting the centroid coordinates of the plane reflector and the centroid coordinates of the light spot, and when the coordinates of the two coincide, the plane reflector is installed and adjusted, otherwise, fine-tuning the plane reflector and the semi-transparent and semi-reflective mirror until the centroid coordinates of the two coincide; wherein the image centroid detection algorithm includes camera video acquisition, image extraction, filtering, contour extraction, and coordinate detection steps.

8. The high-precision semi-automatic adjustment method for laser radar transmitting and receiving modules according to claim 1 is characterized in that: Step S6 specifically includes: using the computer-aided adjustment method in step S1, a standard laser light source and a receiving focusing lens I form an optical subsystem 1, and the adjustment of the receiving focusing lens I is completed; and the optical subsystem is added to the receiving focusing lens II to form an optical subsystem 2, and the adjustment of the receiving focusing lens II is completed. The standard laser light source is removed to complete the adjustment of the focusing lens part of the receiving module.

9. A high-precision semi-automatic adjustment method for laser radar transmitting and receiving modules according to claim 1, characterized in that: Step S7 specifically includes: replacing the standard laser light source in the receiving module with a receiving detector, and assembling the receiving module into the transmitting and receiving integrated module, issuing motion control instructions to move the cross-grained plate on the optical electric guide rail, and fine-tuning the receiving detector forward and backward. If the receiving signal of the receiving detector is weakened, the receiving detector is restored to the position where the receiving signal of the receiving detector is the strongest, and the installation and adjustment of the receiving detector is completed.

10. The high-precision semi-automatic adjustment method for laser radar transmitting and receiving modules according to claim 1, characterized in that: Step S8 specifically includes: fixing the installed transmitting and receiving integrated module, fine-tuning the transmitting and receiving integrated module, observing with an infrared camera so that the light spot can be imaged in the middle of the cross-reticle plate, removing the semi-transparent and semi-reflective mirror, gradually moving the cross-reticle plate on the optical electric guide rail, and recording the distances at different positions and the signal strength of the receiver at this time, until the optical guide rail is at the farthest position, and completing the calibration of the transmitting and receiving integrated module.

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