A high-precision semi-automatic assembly and adjustment method for laser radar transmitting and receiving modules

Abstract

The present invention discloses a high-precision semi-automatic assembly and adjustment method for a laser radar transmitting and receiving module. The method utilizes 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 to quickly and conveniently assemble and adjust the various optical components of the MEMS laser radar transmitting and receiving module. A computer-aided assembly and adjustment method is employed using a phase-shifting interferometer to detect the installation positions of the optical lenses of the transmitting and receiving modules in real time. By automatically moving the optical graticule on the optical guide rail and using an infrared camera to detect the light spot profile, the assembled lenses can be accurately adjusted in real time to ensure that the alignment 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 is calibrated by moving the reflective calibration plate on the optical guide rail. This method can achieve semi-automation of the assembly and adjustment process of the MEMS laser radar transmitting and receiving module, effectively ensuring the assembly and adjustment accuracy of each component while improving the assembly and adjustment efficiency of the MEMS laser radar.

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] LiDAR is currently widely used in the autonomous driving field. Mainstream LiDARs can be categorized into mechanical, semi-solid-state, and solid-state types based on their scanning methods. Mechanical LiDARs suffer from complex mechanical structures, low reliability due to wear of rotating components, and high costs. Solid-state LiDARs, on the other hand, have a low level of technological maturity. Due to these issues, semi-solid-state LiDARs, as the mainstream LiDAR on the market, have become the preferred front-end installation solution for automakers.

[0003] Semi-solid-state lidars primarily include MEMS lidars, rotating mirror lidars, and prism lidars. MEMS lidars, due to their extremely small mirrors, significantly reduce the overall size and weight of the lidar, facilitating integration into various devices. This offers significant advantages for space-constrained applications, such as autonomous vehicles. Furthermore, the MEMS lidar's internal mechanical structure is significantly simplified, reducing wear and failure caused by mechanical motion and improving reliability. Furthermore, the MEMS mirrors move very quickly, enabling rapid scanning and improving the lidar's response speed and data acquisition efficiency. Therefore, MEMS lidars are currently one of the most popular mainstream lidars. Due to their compact structure and limited space, the assembly accuracy of the transmitting and receiving units is a key factor influencing the lidar's overall performance.

[0004] MEMS LiDAR transmitter and receiver 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, placing high demands on factory commissioning. Inefficient commissioning and assembly is a major bottleneck in unlocking production capacity and reducing costs. Currently, there are few assembly and adjustment methods for MEMS LiDARs for autonomous driving, and no assembly and adjustment methods for integrated MEMS LiDAR receiver and transmitter modules have been reported. Furthermore, how to quickly complete the assembly and calibration of integrated receiver and transmitter modules efficiently and without significantly increasing economic costs is one of the challenges that need to be addressed in MEMS LiDAR production. 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. It adopts a computer-aided assembly and adjustment method and utilizes automated guide rail control to monitor the light spot status in real time, thereby realizing semi-automation of the entire assembly and adjustment process of the MEMS laser radar transmitting and receiving module, effectively ensuring the assembly and adjustment accuracy of each component while improving the MEMS laser radar assembly and adjustment efficiency.

[0006] To achieve the above objectives, 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: Install the transmitting module and measure the wavefront aberration of the transmitting module using a phase-shifting interferometer. Correct the position deviation of the fast-axis collimator and the slow-axis collimator of the transmitting module using 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 captured by the infrared camera through a computer, calculate the lengths of the spot in the x and y directions, plot the collected lengths of the spot in the x and y directions to fit 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 reflector, 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 reflector;

[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 coordinates of the mirror centroid 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: Install the receiving module, replace the receiving detector with a standard laser light source, and use a phase-shifting interferometer to measure the wavefront aberration of the receiving module. Use a computer-aided assembly method to correct the position deviation of the receiving focusing lens I and the receiving focusing lens II of the receiving module;

[0014] Step S7: Replace the standard laser light source in the receiving module with a receiving detector, and fine-tune the receiving detector to maximize the signal received by the detector;

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

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

[0017] An optical model of the emission module to be assembled and adjusted is established in 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 no 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 optical design software to obtain the simulated wavefront aberration F0s of the image plane in the optical system; based on 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 using 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 numbering order of the optical subsystems, the optical system is tolerance analyzed using the sensitivity matrix A0 of the fast-axis collimator. 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 rough adjustment is measured using 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 the allowable range. If so, the fast-axis collimator installation is completed.

[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 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 rail cross-section 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 infrared camera field of view.

[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 the 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, to determine 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 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 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 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.

[0026] As a preferred embodiment of the above scheme, step S5 specifically includes: using OPENCV to develop an image centroid detection algorithm to detect the centroid coordinates of the plane reflector and the centroid coordinates of the light spot. When the coordinates of the two coincide, the plane reflector is installed and adjusted. Otherwise, the plane reflector and the semi-transparent and semi-reflective mirror are fine-tuned until the centroid coordinates of the two coincide; 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 to complete the adjustment of the receiving focusing lens I; and the optical subsystem is added to the receiving focusing lens II to form an optical subsystem 2 to complete the adjustment of the receiving focusing lens II, 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 the transmitting and receiving integrated module, issuing motion control instructions to move the cross-grain plate on the optical electric guide rail, and fine-tuning the receiving detector back and forth. 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, and 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 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 present invention has the following beneficial effects:

[0031] The present invention is directed to a MEMS laser radar transmitting and receiving module, and utilizes 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 to quickly and conveniently assemble and adjust the various optical components of the MEMS laser radar transmitting and receiving module. A computer-aided assembly method is employed using a phase-shifting interferometer to detect the installation positions of the optical lenses of the transmitting and receiving modules in real time. By automatically moving the optical graticule on the optical guide rail and using an infrared camera to detect the size of the light spot, the assembled lenses can be accurately adjusted in real time to ensure that the alignment 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 reflective calibration plate on the optical guide rail. This method utilizes a computer-aided assembly method and automated guide rail control to monitor the light spot status in real time, achieving 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. BRIEF DESCRIPTION OF THE DRAWINGS

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

[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 workflow diagram 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 emission module of the present invention;

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

[0038] Figure 6 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-reticle, 16. Electric optical guide rail, 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 this field without making 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 measure the wavefront aberration of the transmitting module 4 using the phase shift interferometer 17. Correct the position deviation of the fast axis collimator 2 and the fast axis collimator 3 of the transmitting module 4 by computer-aided adjustment method.

[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 an optical system is composed of a laser diode 1 and a 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 through simulation analysis; a position deviation Δx no 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 the 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 order of the optical subsystems, a tolerance analysis is performed on the optical system using the sensitivity matrix A0 of the fast-axis collimator 2. 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 results; 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; and the position deviation Δx0 and the deviation type of the fast-axis collimator 2 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 accordingly according to the calculated position deviation Δx0 and the 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 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 installed and adjusted according to the above computer-aided installation method.

[0052] Step S2: Install the transmitting module 4 on the fixture of the electric optical guide 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.

[0053] The transmitting module 4 is mounted on the base of the optical guide rail 16 using an optical clamp to ensure that the optical axis of the transmitting module 4 is as horizontal as possible; a semi-transparent and semi-reflective mirror 14 is mounted between the transmitting module 4 and the cross-grain plate 15 of the electric optical guide rail 16 using an optical clamp; an infrared camera 13 is placed in the reflection 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 captured by the infrared camera 13 through a computer, calculate the length of the spot in the x and y directions, plot the collected lengths of the spot in the x and y directions to fit 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 the spot profile extraction and fitting algorithm, 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 10 ,y 10 . The x-direction radius x1 to x2 corresponding to the above 1 to 10 positions 10 Draw a curve and calculate the slope of the line by linear fitting, which is the slow axis divergence angle. 10 Draw a curve and calculate the slope of the line through linear 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 return light spot position is approximately 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. Use a 905nm infrared sensor at the receiving detector position to observe whether there is a return light spot. If there is, the return light spot is roughly located at the center of the plane reflector, and the installation and adjustment are complete. If not, fine-tune the semi-transparent and semi-reflective mirrors until the infrared sensor shows a return light spot.

[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 coordinates of the mirror centroid 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] Specifically:

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

[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. Correct the position deviation of the receiving focusing lens I 7 and the receiving focusing lens II 9 of the receiving module 8 using a computer-aided adjustment method. Specifically:

[0063] Using the computer-aided adjustment method in step S1, the standard laser light source 18 and the receiving focusing lens I7 form an optical subsystem 1, and the adjustment of the receiving focusing lens I7 is completed; and the optical subsystem is added to the 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 weakens, restore the receiving detector 6 to the position where the receiving signal is strongest.

[0066] Step S8: Fix the integrated transmitter-receiver module 11, return the position of the crosshair plate 15 on the motorized optical guide rail 16 to zero, and gradually move the crosshair plate 15 on the motorized optical guide rail 16. Record the signal strength of the receiving detector 6 at the corresponding distance at this time. This completes the intensity calibration of the integrated transmitter-receiver module 11, and the installation and calibration of the integrated transmitter-receiver module 11 are completed. Specifically:

[0067] Fix the transmitting and receiving integrated module 11, fine-tune the transmitting and receiving integrated module 11, use the infrared camera 13 to observe, so that the light spot can be imaged in the middle of the cross-hair plate 15, remove the semi-transparent and semi-reflective mirror 14, move the cross-hair plate 15 step by step, and record the distance at different positions and the signal strength of the detection receiver 6 at this time, until the cross-hair plate 15 is located at the farthest position of the optical guide rail 16, and the calibration of the transmitting and receiving integrated module 11 is completed.

[0068] This embodiment is aimed at the MEMS laser radar transmitting and receiving module. It uses simple measuring equipment such as optical gratings, optical guides, semi-transparent and semi-reflective mirrors, infrared cameras, and phase-shifting interferometers to quickly and conveniently assemble and adjust the various optical components of the MEMS laser radar transmitting and receiving module. A computer-assisted assembly method is used to monitor the installation position of the optical lenses of the transmitting and receiving modules using a phase-shifting interferometer. By automatically moving the optical grating 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 alignment 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 reflective calibration plate on the optical guide. This method uses a computer-assisted assembly method and uses automated guides to control real-time monitoring of the light spot status 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 merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A high-precision semi-automatic assembly and adjustment method for a laser radar transmitting and receiving module, characterized in that: The following steps are involved: Step S1: Install the transmitting module and measure the wavefront aberration of the transmitting module using a phase-shifting interferometer. Correct the position deviation of the fast-axis collimator and the slow-axis collimator of the transmitting module using 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 captured by the infrared camera through a computer, calculate the lengths of the spot in the x and y directions, plot the collected lengths of the spot in the x and y directions to fit 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 reflector, 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 reflector; Step S5: using an image centroid detection algorithm to detect the centroid position of the light spot on the plane reflector, so that the coordinates of the mirror centroid 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: Install the receiving module, replace the receiving detector with a standard laser light source, and use a phase-shifting interferometer to measure the wavefront aberration of the receiving module. Use a computer-aided assembly method to correct the position deviation of the receiving focusing lens I and the receiving focusing lens II of the receiving module; Step S7: Replace the standard laser light source in the receiving module with a receiving detector, and fine-tune the receiving detector to maximize the signal received by the detector; Step S8: Fix the integrated transmitter-receiver module, return the position of the crosshair plate on the electric optical guide rail to zero, and gradually move the crosshair plate on the electric optical guide rail to record the signal strength of the receiving detector corresponding to the distance at this time. The intensity calibration of the integrated transmitter-receiver module is completed, and the installation and calibration of the integrated transmitter-receiver module are completed.

2. A high-precision semi-automatic assembly and 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 assembled and adjusted is established in 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 no 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 optical design software to obtain the simulated wavefront aberration F0s of the image plane in the optical system; based on 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 using the sensitivity matrix formula, and the sensitivity matrix A0 of the fast-axis collimator is extracted; A0=(F0s-F0n) / Δx0s; According to the numbering order of the optical subsystems, the optical system is tolerance analyzed using the sensitivity matrix A0 of the fast-axis collimator. 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 rough adjustment is measured using 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 the allowable range. If so, the fast-axis collimator installation is completed.

3. The high-precision semi-automatic assembly and adjustment method of a laser radar transmitting and receiving module according to claim 1, characterized in that: Step S2 specifically includes: with the help of the optical guide rail base and the optical clamp, the assembled 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 rail cross-grid plate through the 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 assembly and adjustment method of a laser radar transmitting and receiving module according to claim 1, 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 the 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, to determine whether the divergence angle meets the design indicators.

5. A high-precision semi-automatic assembly and adjustment method for a laser radar transmitting and receiving module 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. The high-precision semi-automatic assembly and adjustment method of a laser radar transmitting and receiving module 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 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. The high-precision semi-automatic assembly and adjustment method of 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. When the coordinates of the two coincide, the plane reflector is installed. Otherwise, fine-tune the plane reflector and the semi-transparent and semi-reflective mirror until the centroid coordinates of the two coincide. The image centroid detection algorithm includes camera video acquisition, image extraction, filtering, contour extraction, and coordinate detection steps.

8. The high-precision semi-automatic assembly and adjustment method of a laser radar transmitting and receiving module according to claim 1, characterized in that: Step S6 specifically includes: using the computer-aided adjustment method in step S1, the 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. The standard laser light source is removed to complete the adjustment of the focusing lens part of the receiving module.

9. The high-precision semi-automatic assembly and adjustment method of a laser radar transmitting and receiving module 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-grain plate on the optical electric guide rail, and fine-tuning the receiving detector back and forth. If the receiving signal of the receiving detector weakens, the receiving detector is restored to the position where the receiving signal of the receiving detector is the strongest, and the installation of the receiving detector is completed.

10. The high-precision semi-automatic assembly and adjustment method of a laser radar transmitting and receiving module according to claim 1, characterized in that: Step S8 specifically includes: fixing the installed integrated transmitting and receiving module, fine-tuning the integrated transmitting and receiving 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 at this time, until the optical guide rail is at the farthest position, thereby completing the calibration of the integrated transmitting and receiving module.

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