Vehicle-mounted laser radar detection optical axis adaptive adjustment device and method
By combining a gravity collimation unit and a leveling execution unit with a scanning algorithm, the problem of non-perpendicular detection direction of vehicle-mounted lidar on uneven roads is solved, realizing vertical measurement and efficient adjustment of lidar under any road conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-03-20
AI Technical Summary
During the detection process, changes in the environment and uneven road surfaces can cause the detection direction to be non-perpendicular to the ground, resulting in measurement errors and inaccurate echo signals. Traditional adjustment methods are inconvenient and time-consuming.
The system employs a gravity collimation unit and a leveling execution unit. Using the direction of gravity as a reference, the pose of the lidar is adjusted through a combination of reflectors and a leveling mechanism. Combined with coarse and fine scanning algorithms, the optical axis is adaptively adjusted to ensure that the laser emission direction is consistent with the direction of gravity.
Vertical detection by lidar was achieved on uneven road surfaces, improving measurement accuracy and ease of operation while reducing setup time.
Smart Images
Figure CN121703793A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of laser radar atmospheric detection, in particular to a vehicle-mounted laser radar detection optical axis self-adaptive adjustment method and device. BACKGROUND
[0002] The laser radar is an active optical remote sensing device, which has obvious advantages in atmospheric detection. The vehicle-mounted laser radar is a mobile atmospheric measurement device, which has better flexibility. In the working process, due to the change of environmental temperature, the vibration caused by the driving of the vehicle, and the unevenness of the road when stopping for measurement, etc., the detection direction of the vehicle-mounted laser radar may not be perpendicular to the ground during the detection process.
[0003] In the actual use process of the vehicle-mounted laser radar, the outgoing laser light path is consistent with the direction of gravity, so that the vertical extinction profile of the atmosphere at the point can be accurately measured. The traditional method needs to be manually adjusted according to the specific situation of the vehicle parking position, which is not convenient to operate, and a lot of leveling time is required. SUMMARY
[0004] The purpose of the present application is to provide a vehicle-mounted laser radar detection optical axis self-adaptive adjustment device and method, which uses the direction of gravity as a reference to solve the problem of shortening of the radar detection distance and misalignment of the echo signal caused by the non-perpendicularity of the detection optical axis to the ground.
[0005] In order to achieve the above-mentioned task, the present application adopts the following technical scheme: The vehicle-mounted laser radar detection optical axis self-adaptive adjustment device comprises an outgoing light path gravity collimation unit and a leveling execution unit, wherein: The outgoing light path gravity collimation unit comprises a light-shielding sealed box mounted on the outgoing light path of the laser radar, the top plate and the bottom plate of the light-shielding sealed box are respectively provided with a light inlet and a light outlet, and a gravity collimation pipe with a counterweight is hingedly mounted at the top of the light-shielding sealed box; the laser emitted by the laser of the laser radar is reflected into the atmosphere through the light inlet, the light-shielding sealed box, the gravity collimation pipe and the light outlet through the combination of the mirrors; The leveling execution unit comprises a fixed top plate, a radar mounting plate and a leveling mechanism, wherein the fixed top plate is mounted on the vehicle, the laser radar is mounted on the radar mounting plate, and the leveling mechanism is arranged between the fixed top plate and the radar mounting plate; the leveling mechanism is controlled by the radar host computer, and drives the radar mounting plate to rotate to adjust the pose of the laser radar, so as to calibrate the laser optical axis.
[0006] Further, the mirror combination comprises a first mirror arranged at the lower part of the light inlet, a second mirror arranged at the upper part of the light outlet, and a third mirror arranged at one side of the second mirror.
[0007] Further, a hinge base is arranged at the top of the gravity collimator, and a hinge mounting frame is arranged on the hinge base, and a spherical hinge is arranged in the hinge mounting frame.
[0008] Further, the leveling mechanism comprises first to fourth adjusting arms arranged at four vertices of a rectangle on the fixed top plate and the radar mounting plate.
[0009] Further, a set of opposite rectangles are first determined on the fixed top plate and the radar mounting plate, and the first to fourth adjusting arms are arranged at four vertices of the rectangle; a line connecting the mounting positions of the first adjusting arm and the third adjusting arm on the fixed top plate is taken as an X axis, and a line connecting the mounting positions of the fourth adjusting arm and the third adjusting arm on the fixed top plate is taken as a Y axis; the second adjusting arm and the fourth adjusting arm are adjusted to enable the radar mounting plate to rotate about the X axis; and the third adjusting arm and the fourth adjusting arm are adjusted to enable the radar mounting plate to rotate about the Y axis.
[0010] Further, the linear electric cylinder is driven by an electric cylinder driver, and the electric cylinder driver can drive the linear electric cylinder to extend or retract by a corresponding length at different step lengths; each step length is a minimum unit of single extension or retraction of the linear electric cylinder; and each step length corresponds to a fixed number of degrees of rotation of the radar mounting plate about the X axis / Y axis.
[0011] A vehicle-mounted laser radar detection optical axis self-adaptive adjustment method, comprising: When the vehicle carrying the laser radar travels on a bumpy road, the gravity collimator is always perpendicular to the horizontal plane under the action of the counterweight; if the laser of the laser radar is blocked by the gravity collimator or the light-shielding sealing box due to the pose of the vehicle, the radar echo signal will be attenuated; the radar host computer judges the strength of the radar echo signal, and when the strength is less than a set threshold, the radar host computer controls the triggering of the self-adaptive adjustment algorithm, comprising: The leveling execution unit is controlled to perform coarse scanning and fine scanning, so that the radar mounting plate drives the laser radar to produce controllable two-dimensional angular deflection, so that the optical axis of the laser is aligned with the direction of gravity; at this time, the laser emitted by the laser is reflected by the third mirror in a direction perpendicular to the horizontal plane to the atmosphere.
[0012] Further, the signal-to-noise ratio of the radar echo signal is taken as a calibration criterion in the coarse scanning stage; the radar host computer drives the first to fourth adjusting arms to drive the radar mounting plate to perform global cross scanning about the X / Y axis through the electric cylinder driver; the specific process is as follows: First, the first adjusting arm, the third adjusting arm are fixed, the second adjusting arm, the fourth adjusting arm are synchronously driven with a preset first step value, so that the radar mounting plate scans in a first preset angle range around the X axis; the scanning refers to the process that the radar host computer continuously collects radar echoes through the laser radar; in the scanning process, the radar host computer determines the first position when the signal-to-noise ratio is maximum in the scanning process around the X axis through continuous determination of the signal-to-noise ratio of the radar echo signal; then the first adjusting arm and the second adjusting arm are fixed at the first position, and the third adjusting arm and the fourth adjusting arm are synchronously driven with the first step value, so that the radar mounting plate scans in a second preset angle range around the Y axis, thereby determining the second position when the signal-to-noise ratio is maximum in the scanning process around the Y axis.
[0013] Further, the peak position of the radar echo signal is used as the calibration criterion in the fine scanning stage; first, based on the second position determined after coarse scanning, a scanning angle range is determined in the X axis and Y axis directions respectively with the second position as the center, thereby forming a fine scanning region; point-by-point scanning is performed in the fine scanning region using a second step value until each position in the fine scanning region is scanned; finally, when the peak position of the radar echo signal at a certain position in the fine scanning region coincides with the preset collimation criterion, it is determined that the optical axis of the laser is aligned with the direction of gravity, and the position of the radar mounting plate at this time is fixed, that is, the detection operation can be started.
[0014] Further, the collimation criterion refers to the peak position of the radar echo signal recorded by using a collimator when the laser emitted by the laser is reflected by the third mirror to the atmosphere in a direction perpendicular to the horizontal plane.
[0015] Compared with the prior art, the present application has the following technical features: When the vehicle is detecting on uneven road surface, the gravity collimator with counterweight always keeps vertical to the ground under the action of gravity, at this time, if the laser emission direction is inclined, part or all of the laser beam will be blocked by the gravity collimator, resulting in a significant decrease in the signal-to-noise ratio of the echo signal or even complete disappearance of the signal. Based on this characteristic, the software algorithm unit drives the leveling execution unit to work by analyzing the echo signal quality in real time: by driving the four adjusting arms with the linear cylinder, the radar mounting plate is accurately adjusted in the X / Y two perpendicular directions in the plane until the optical axis of the emitted laser is parallel to the central axis of the gravity collimator, thereby realizing the function that the laser radar can maintain vertical ground detection under any road surface conditions. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 It is an emission light path gravity collimation unit of the application; Figure 2 It is an emission light path gravity collimation unit of the application in the case of inclined detection; Figure 3 A schematic diagram of the leveling execution unit of the invention; Figure 4 A schematic diagram of the fixed top plate of the leveling execution unit of the invention; Figure 5 The system software flowchart for the invention; Figure 6 A comparison chart of the signal-to-noise ratio of the coarse scan echo signal for the invention; Figure 7 A comparison diagram of the number of photons in the fine-scan echo signal for the invention.
[0017] Explanation of reference numerals in the attached drawings: 1-1 First reflector, 1-2 Second reflector, 1-3 Third reflector, 2-1 Light-shielding sealing box, 2-2 Hinge base, 2-3 Spherical hinge, 2-4 Hinge mounting bracket, 2-5 Gravity collimator, 2-6 Counterweight, 3-1 Fixed top plate, 3-2 Radar mounting plate, 3-3 Upper spherical hinge seat, 3-4 Upper articulated ball, 3-5 Upper mounting bracket, 3-6 Linear electric cylinder, 3-7 Electric cylinder actuator, 3-8 Lower mounting bracket, 3-9 Lower articulated ball, ① First adjusting arm, ② Second adjusting arm, ③ Third adjusting arm, ④ Fourth adjusting arm. Detailed Implementation
[0018] This invention first provides a vehicle-mounted lidar detection optical axis adaptive adjustment device, such as... Figure 1 As shown, the device includes an output optical path gravity collimation unit and a leveling execution unit, wherein: 1. Gravity collimation unit for outgoing light path.
[0019] The gravity collimation unit for the output light path includes a light-shielding sealed box 2-1 installed on the output light path of the lidar. The top and bottom plates of the light-shielding sealed box 2-1 are respectively provided with a light inlet and a light outlet. A gravity collimation tube 2-5 with a counterweight 2-6 is hinged to the top of the light-shielding sealed box 2-1. A first reflector 1-1 is provided at the lower part of the light inlet, a second reflector 1-2 is provided at the upper part of the light outlet, and a third reflector 1-3 is provided on one side of the second reflector 1-2. The laser emitted by the lidar laser is reflected by the first reflector 1-1, enters the light-shielding sealed box 2-1 through the light inlet, passes through the gravity collimation tube 2-5, and exits from the light outlet onto the second reflector 1-2. Finally, it is reflected into the atmosphere by the third reflector 1-3. It is required that the laser light path after reflection by the third reflector 1-3 is consistent with the direction of gravity in order to accurately measure the vertical extinction profile of the atmosphere.
[0020] In this embodiment of the invention, a hinge base 2-2 is provided at the top inside the gravity collimating tube 2-5, a hinge mounting bracket 2-4 is mounted on the hinge base 2-2, a spherical hinge 2-3 is provided in the hinge mounting bracket 2-4, and the upper end of the gravity collimating tube 2-5 is connected to the spherical hinge 2-3.
[0021] When the current parking surface of the vehicle is flat, the laser emitted by the laser can be finally reflected by the third mirror 1-3 in a direction perpendicular to the horizontal plane into the atmosphere, at which time no adjustment of the laser radar is required, which is the ideal state; when the parking surface of the vehicle carrying the laser radar is an uneven inclined surface, due to the hinged installation of the gravity collimator 2-5, its axis is always perpendicular to the horizontal plane under the action of the counterweight 2-6; but at this time, because there is an angle between the laser radar and the horizontal plane, the emitted laser of the laser will be blocked by the gravity collimator 2-5, as shown in Figure 2 At this time, it is necessary to adjust the attitude of the laser radar.
[0022] 2. Leveling execution unit.
[0023] The leveling execution unit comprises a fixed top plate 3-1, a radar mounting plate 3-2 and a leveling mechanism, wherein: The fixed top plate 3-1 is fixedly connected to the vehicle by screws, and the laser radar is fixedly installed on the radar mounting plate 3-2; the leveling mechanism comprises first to fourth adjusting arms arranged at the four corners of the fixed top plate 3-1 and the radar mounting plate 3-2; the first to fourth adjusting arms are the same in structure, and the first adjusting arm comprises a linear electric cylinder 3-6 and upper and lower spherical hinge mechanisms arranged at the upper and lower ends thereof; the upper spherical hinge mechanism comprises an upper joint ball 3-4 installed at the upper end of the linear electric cylinder 3-6, and the upper joint ball 3-4 is installed on an upper spherical hinge seat 3-3 arranged on the fixed top plate 3-1 through an upper mounting bracket 3-5; the lower spherical hinge mechanism comprises a lower joint ball 3-9 installed at the lower end of the linear electric cylinder 3-6, and the lower joint ball 3-9 is installed on a lower spherical hinge seat arranged on the radar mounting plate 3-2 through a lower mounting bracket 3-8.
[0024] For the first to fourth adjusting arms, the position and attitude of the radar mounting plate 3-2 can be adjusted by driving the linear electric cylinder 3-6 to extend and retract under the cooperation of the upper and lower spherical hinge mechanisms.
[0025] As Figure 4As shown, in the embodiment of the present application, a relative group of rectangles is first determined on the fixed top plate 3-1 and the radar mounting plate 3-2, and the first to fourth adjusting arms are arranged at the four vertices of the rectangle; the line connecting the installation positions of the first adjusting arm and the third adjusting arm on the fixed top plate 3-1 is taken as the X axis, the line connecting the installation positions of the fourth adjusting arm and the third adjusting arm on the fixed top plate 3-1 is taken as the Y axis, and the first adjusting arm is taken as the reference fixed arm, then the second adjusting arm and the fourth adjusting arm are adjusted to make the radar mounting plate 3-2 rotate around the X axis; the third adjusting arm and the fourth adjusting arm are adjusted to make the radar mounting plate 3-2 rotate around the Y axis; during the position adjustment of the radar mounting plate 3-2, the synchronous belt drives the laser radar to adjust the position and posture, so as to adjust the laser exit light path of the laser radar, and finally make the exit light path after being reflected by the third reflector consistent with the direction of gravity.
[0026] The linear motor cylinder 3-6 is driven by the motor cylinder driver 3-7, and the motor cylinder driver 3-7 can drive the linear motor cylinder 3-6 to stretch and contract by a corresponding length at different steps; wherein one step is the minimum unit of single stretching and contraction of the linear motor cylinder 3-6; each step corresponds to a fixed number of degrees of rotation of the radar mounting plate 3-2 around the X axis / Y axis, such as 1°.
[0027] On the basis of the above technical solution, the present application further provides a vehicle-mounted laser radar detection optical axis self-adaptive adjustment method, comprising: When the vehicle carrying the laser radar runs on a bumpy road, because the gravity collimating tube 2-5 is installed in a hinged manner, its axis is always perpendicular to the horizontal plane under the action of the counterweight 2-6; if the laser radar is caused by the pose of the vehicle to cause the emitted laser of the laser radar to be blocked by the gravity collimating tube 2-5 or the light-shielding sealed box 2-1, the radar echo signal will be attenuated; the radar host computer judges the strength of the radar echo signal, and when it is less than a set threshold, the radar host computer controls the triggering of the self-adaptive adjustment algorithm, which is as follows: The first to fourth adjusting arms in the leveling execution unit perform coarse scanning and fine scanning, so that the radar mounting plate 3-2 drives the laser radar to produce controllable two-dimensional angular deflection until the adjustment process is completed, so that the optical axis of the laser completes alignment with the direction of gravity; at this time, the laser emitted by the laser is reflected by the third reflector 1-3 in a direction perpendicular to the horizontal plane to the atmosphere.
[0028] (1) Coarse scanning.
[0029] The signal-to-noise ratio of the radar echo signal is taken as the calibration criterion in the coarse scanning stage; the radar host computer drives the first to fourth adjusting arms to drive the radar mounting plate 3-2 to perform global cross scanning around the X / Y axis through the motor cylinder driver 3-7, and the specific process is as follows: First, the first adjusting arm and the third adjusting arm are fixed, and the second adjusting arm and the fourth adjusting arm are synchronously driven by a preset first step value, so that the radar mounting plate 3-2 is scanned in a first preset angle range around the X axis; the scanning refers to the process that the radar host computer continuously collects radar echoes through the laser radar; during the scanning process, the radar host computer determines the first position when the signal-to-noise ratio is maximum during the scanning around the X axis through continuous determination of the signal-to-noise ratio of the radar echo signal; then the first adjusting arm and the second adjusting arm are fixed at the first position, and the third adjusting arm and the fourth adjusting arm are synchronously driven by the first step value, so that the radar mounting plate 3-2 is scanned in a second preset angle range around the Y axis, so as to determine the second position when the signal-to-noise ratio is maximum during the scanning around the Y axis; the second position is the position when the signal-to-noise ratio reaches the maximum value during the scanning around the X / Y axis, and the coarse scanning process is completed. The position is used as the starting point of fine scanning, and the initial position of each fine scanning is different due to the coarse scanning result, and has dynamic adaptability.
[0030] In the embodiment of the application, the first step value is 5 steps; the first and second preset angle ranges are determined according to actual needs, for example, the angle between the positive and negative limit positions during rotation around the X axis can be set as the first angle range; but in actual application, the entire range may not need to be scanned, and should be adjusted as appropriate.
[0031] (2) Fine scanning.
[0032] The peak position of the radar echo signal is used as the calibration criterion in the fine scanning stage; first, based on the second position determined after coarse scanning, a scanning angle range is determined in the X axis and Y axis directions respectively with the second position as the center, so as to form a fine scanning region; in the fine scanning region, point-by-point scanning is performed by using a second step value, for example, the radar mounting plate 3-2 can be first driven to rotate around the X axis by a second step value, and then scanned in the scanning angle range of the Y axis around the Y axis, until each position in the fine scanning region is scanned; finally, when the peak position of the radar echo signal at a certain position in the fine scanning region coincides with the preset collimation criterion, it is determined that the optical axis of the laser is aligned with the direction of gravity, and the position of the radar mounting plate 3-2 at this time is fixed, and the detection operation can be started.
[0033] The collimation criterion refers to the peak position of the radar echo signal collected and recorded when the laser emitted by the laser is reflected to the atmosphere by the third mirror 1-3 in a direction perpendicular to the horizontal plane (the direction of gravity). The collimation criterion is a preset reference value, which is obtained through pre-calibration (such as using a collimator) and stored in the radar host computer.
[0034] The second step value is less than the first step value, and in the embodiment, the second step value is 1 step, that is, the radar mounting plate 3-2 is rotated by 1° in the X / Y axis direction in the fine scanning area each time. The fine scanning area range is a preset smaller area, for example, a scanning angle range of 2 steps before and after the coordinates of the center in the X / Y axis direction is determined in the X axis and Y axis direction with the second position as the center, so as to form a 5-step x 5-step fine scanning area.
[0035] In the application, the combination of coarse scanning and fine scanning can improve the optical axis adjustment efficiency while ensuring the accuracy.
[0036] Figure 6 With Figure 7 The results obtained in the experimental verification stage of the embodiment of the application.
[0037] Figure 6 The figure is a comparison of the signal-to-noise ratio of the radar echo signal before and after coarse scanning; the results show that after coarse scanning, the signal-to-noise ratio decreases with the decrease of the detection distance, which indicates that the laser radar has initially restored the vertical detection state; Figure 7 The figure is a comparison of the radar echo photon number curve before and after fine scanning; it can be seen that after fine scanning, the peak position of the echo coincides with the preset collimation criterion (for example, at sampling point 26), and the signal attenuation trend is more gentle, which indicates that the optical axis alignment accuracy is further improved, and the system has restored to the ideal vertical detection state. The above results verify the feasibility and effectiveness of the present application in the optical axis self-adaptive adjustment.
[0038] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.
Claims
1. A vehicle-mounted lidar detection optical axis adaptive adjustment device, characterized in that, It includes an output optical path gravity collimation unit and a leveling execution unit, wherein: The gravity collimation unit for the output optical path includes a light-shielding and sealing box (2-1) installed on the output optical path of the lidar. The top and bottom plates of the light-shielding and sealing box (2-1) are respectively provided with light inlet and light outlet. The top of the light-shielding and sealing box (2-1) is hinged to a gravity collimation tube (2-5) with a counterweight (2-6). The laser emitted by the lidar laser is reflected into the atmosphere through the light inlet, the light-shielding and sealing box (2-1), the gravity collimation tube (2-5), and the light outlet by a combination of reflectors. The leveling execution unit includes a fixed top plate (3-1), a radar mounting plate (3-2), and a leveling mechanism. The fixed top plate (3-1) is mounted on the vehicle, the lidar is mounted on the radar mounting plate (3-2), and the leveling mechanism is located between the fixed top plate (3-1) and the radar mounting plate (3-2). The leveling mechanism is controlled by the radar host computer and drives the radar mounting plate (3-2) to rotate to adjust the position and orientation of the lidar, thereby calibrating the laser optical axis.
2. The vehicle-mounted lidar detection optical axis adaptive adjustment device according to claim 1, characterized in that, The reflector assembly includes a first reflector (1-1) disposed at the lower part of the light inlet, a second reflector (1-2) disposed at the upper part of the light outlet, and a third reflector (1-3) disposed on one side of the second reflector (1-2).
3. The vehicle-mounted lidar detection optical axis adaptive adjustment device according to claim 1, characterized in that, A hinge base (2-2) is provided at the top inside the gravity collimator (2-5), a hinge mounting bracket (2-4) is mounted on the hinge base (2-2), a spherical hinge (2-3) is provided in the hinge mounting bracket (2-4), and the upper end of the gravity collimator (2-5) is connected to the spherical hinge (2-3).
4. The vehicle-mounted lidar detection optical axis adaptive adjustment device according to claim 1, characterized in that, The leveling mechanism includes a first to a fourth adjusting arm located at the four vertices of a rectangle at relative positions on the fixed top plate (3-1) and the radar mounting plate (3-2). The first to fourth adjusting arms have the same structure, including a linear electric cylinder (3-6) and an upper ball joint mechanism and a lower ball joint mechanism located at their upper and lower ends.
5. The vehicle-mounted lidar detection optical axis adaptive adjustment device according to claim 1, characterized in that, First, determine a set of opposite rectangles on the fixed top plate (3-1) and the radar mounting plate (3-2). Arrange the first to fourth adjusting arms at the four vertices of the rectangles. Take the line connecting the installation positions of the first and third adjusting arms on the fixed top plate (3-1) as the X-axis and the line connecting the installation positions of the fourth and third adjusting arms on the fixed top plate (3-1) as the Y-axis. Adjusting the second and fourth adjusting arms will allow the radar mounting plate (3-2) to rotate around the X-axis. Adjusting the third and fourth adjusting arms will allow the radar mounting plate (3-2) to rotate around the Y-axis.
6. The vehicle-mounted lidar detection optical axis adaptive adjustment device according to claim 1, characterized in that, The linear electric cylinder (3-6) is driven by the electric cylinder driver (3-7), which can drive the linear electric cylinder (3-6) to extend and retract to the corresponding length with different step lengths; where (1) step length is the smallest unit of a single extension and retraction of the linear electric cylinder (3-6); each step length corresponds to a fixed degree of rotation of the radar mounting plate (3-2) around the X-axis / Y-axis.
7. A method for adaptive adjustment of the optical axis of a vehicle-mounted lidar detector, characterized in that, include: When the lidar carrier vehicle is traveling on a bumpy road, the axis of the gravity collimator (2-5) is always perpendicular to the horizontal plane under the action of the counterweight (2-6). If the lidar's laser output is blocked by the gravity collimator (2-5) or the light-shielding sealing box (2-1) due to the position of the carrier vehicle, the radar echo signal will be attenuated. The radar host computer determines the strength of the radar echo signal. When the strength is less than a set threshold, the host computer triggers an adaptive adjustment algorithm, including: By controlling the leveling execution unit to perform coarse and fine scanning, the radar mounting plate (3-2) drives the lidar to generate a controllable two-dimensional angle deflection, so that the optical axis of the laser is aligned with the direction of gravity; at this time, the laser emitted by the laser is reflected into the atmosphere by the third reflector (1-3) in a direction perpendicular to the horizontal plane.
8. The adaptive adjustment method for the optical axis of a vehicle-mounted lidar detector according to claim 7, characterized in that, In the coarse scan stage, the signal-to-noise ratio of the radar echo signal is used as the calibration criterion; the radar host computer drives the first to fourth adjustment arms through the electric cylinder driver (3-7) to move the radar mounting plate (3-2) to perform a global cross scan around the X / Y axis. The specific process is as follows: First, the first and third adjusting arms are fixed, and the second and fourth adjusting arms are synchronously driven with a preset first step value, so that the radar mounting plate (3-2) scans around the X-axis within a first preset angle range. The scanning refers to the process by which the radar host computer continuously collects radar echoes through the lidar. During the scanning process, the radar host computer determines the first position where the signal-to-noise ratio is the largest during the X-axis scanning process by continuously judging the signal-to-noise ratio of the radar echo signal. Then, the first and second adjusting arms are fixed at the first position, and the third and fourth adjusting arms are synchronously driven with the first step value, so that the radar mounting plate (3-2) scans around the Y-axis within a second preset angle range, thereby determining the second position where the signal-to-noise ratio is the largest during the Y-axis scanning process.
9. The adaptive adjustment method for the optical axis of a vehicle-mounted lidar detector according to claim 7, characterized in that, In the fine scanning stage, the peak position of the radar echo signal is used as the calibration criterion. First, based on the second position determined after the coarse scan, a scanning angle range is determined in the X and Y axes with the second position as the center, thus forming the fine scanning area. In the fine scanning area, the second step value is used to scan point by point until every position in the fine scanning area is scanned. Finally, when the peak position of the radar echo signal at a certain position in the fine scanning area coincides with the preset collimation criterion, it is determined that the optical axis of the laser is aligned with the direction of gravity. The position of the radar mounting plate (3-2) is fixed at this time, and the detection operation can begin.
10. The adaptive adjustment method for the optical axis of a vehicle-mounted lidar detector according to claim 9, characterized in that, The collimation criterion refers to the use of a collimator to determine the peak position of the collected and recorded radar echo signal when the laser emitted from the laser is reflected into the atmosphere by the third reflecting mirror (1-3) in a direction perpendicular to the horizontal plane.