Method and system for adjusting the optical axis of a LiDAR sensor

Abstract

This system allows for easy and highly accurate horizontal adjustment of the optical axis of a LiDAR sensor. [Solution] The method for adjusting the optical axis of the LiDAR sensor 10 includes the steps of: irradiating with a horizontal laser beam HL; placing a measuring rod 14 at a first point 30; aligning the horizontal laser beam HL with a positioning marker 20; adjusting the position of the laser detector 22 on a slider unit 18 so that the sensor laser beam SL coincides with the reference point of the laser detector 22; placing a measuring rod 14 at a second point 32 that is point-symmetric to the first point 30; aligning the horizontal laser beam HL with the positioning marker 20; measuring the height difference between the sensor laser beam SL and the reference point using the laser detector 22; and adjusting the angle of the optical axis of the LiDAR sensor 10 so that the height position of the sensor laser beam SL at the second point 32 is shifted toward the reference point by half the height difference.

Description

Technical Field

[0001] The present invention relates to a method for adjusting the optical axis of a LiDAR sensor and an optical axis adjustment system.

Background Art

[0002] Conventionally, an automated guided forklift (AGF) configured to measure its own position by mounting a two-dimensional (2D)-LiDAR (Light Detction And Ranging) sensor is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described automated guided forklift, in order to accurately measure its own position, it is necessary to adjust the optical axis of the LiDAR sensor horizontally with high precision with respect to the floor of a factory or a warehouse.

[0005] The present invention has been made in view of such a situation, and an object thereof is to simply and accurately adjust the optical axis of the LiDAR sensor horizontally.

Means for Solving the Problems

[0006] To solve the above problems, an optical axis adjustment method according to one aspect of the present invention is an optical axis adjustment method for a LiDAR sensor, comprising the steps of: irradiating a horizontal laser beam at a predetermined height; and positioning a measuring rod vertically at a first point at a predetermined distance from the LiDAR sensor, wherein the measuring rod is provided with a slider portion that is movable along its longitudinal direction, and the slider portion is provided with a marker for alignment with the horizontal laser beam and a laser detector capable of measuring the height position of the sensor laser beam irradiated from the LiDAR sensor, and the laser detector is position adjustable on the slider portion, and at the first point, moving the slider portion relative to the measuring rod to position the horizontal laser beam and the marker The system includes the steps of: aligning the sensor and the laser detector; adjusting the position of the laser detector on the slider at the first point so that the sensor laser beam coincides with the reference point of the laser detector; positioning a surveying rod vertically at a second point that is point-symmetric to the first point with respect to the LiDAR sensor; moving the slider at the second point with respect to the surveying rod to align the horizontal laser beam with the alignment marker; measuring the height difference between the sensor laser beam and the reference point at the second point using the laser detector; and adjusting the angle of the optical axis of the LiDAR sensor so that the height position of the sensor laser beam at the second point is shifted towards the reference point by half the height difference.

[0007] Another aspect of the present invention is also a method for adjusting the optical axis. This method is a method for adjusting the optical axis of a LiDAR sensor, comprising the steps of: irradiating a horizontal laser beam to the height of a reference plane of the LiDAR sensor; positioning a measuring rod vertically at a first point at a predetermined distance from the LiDAR sensor, wherein the measuring rod is provided with a slider portion that is movable along its longitudinal direction, and the slider portion is provided with a marker for alignment with the horizontal laser beam and a reflectance changing portion that changes the reflectance to the sensor laser beam irradiated from the LiDAR sensor by comparing it with the slider portion and other parts of the measuring rod, wherein the reflectance changing portion has a height smaller than the height of the sensor laser beam that is permissible at a predetermined distance, and the height from the alignment marker to the center of the reflectance changing portion is equal to the height from the reference plane of the LiDAR sensor to the optical axis; and moving the slider portion relative to the measuring rod at the first point to align the horizontal laser beam with the alignment marker; and adjusting the angle of the optical axis of the LiDAR sensor so that the reflectance changing portion can be detected by the LiDAR sensor.

[0008] A further aspect of the present invention is an optical axis adjustment system. This optical axis adjustment system is for a LiDAR sensor and comprises a horizontal laser irradiator that irradiates a horizontal laser beam at a predetermined height, and a measuring rod positioned vertically at a predetermined distance from the LiDAR sensor, the measuring rod having a slider portion that is movable along its longitudinal direction, the slider portion being equipped with a marker for alignment with the horizontal laser beam, and a laser detector capable of measuring the height position of the sensor laser beam irradiated from the LiDAR sensor, the laser detector being position adjustable on the slider portion.

[0009] Another aspect of the present invention is also an optical axis adjustment system. This optical axis adjustment system is for a LiDAR sensor and comprises: a horizontal laser irradiator that irradiates a horizontal laser beam to the height of the reference plane of the LiDAR sensor; and a measuring rod that is positioned vertically at a predetermined distance from the LiDAR sensor, and is provided with a slider portion that is movable along its longitudinal direction, the slider portion being provided with a marker for alignment with the horizontal laser beam, and a reflectance changing portion that changes the reflectance to the sensor laser beam irradiated from the LiDAR sensor by comparing it with the slider portion and other parts of the measuring rod, the reflectance changing portion being smaller in height than the allowable height of the sensor laser beam at a predetermined distance, and the height from the alignment marker to the center of the reflectance changing portion being equal to the height from the reference plane of the LiDAR sensor to the optical axis.

[0010] Furthermore, any combination of the above components, or any substitution of the components or expressions of the present invention between methods, apparatus, systems, etc., are also valid embodiments of the present invention. [Effects of the Invention]

[0011] According to the present invention, the optical axis of a LiDAR sensor can be adjusted horizontally in a simple and highly accurate manner. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view illustrating the optical axis adjustment system according to the first embodiment. [Figure 2] This is a plan view illustrating the optical axis adjustment system according to the first embodiment. [Figure 3] This is a flowchart illustrating a method for adjusting the optical axis of a LiDAR sensor using the optical axis adjustment system according to the first embodiment. [Figure 4] This is a side view illustrating the optical axis adjustment system according to the second embodiment. [Figure 5]This is a flowchart illustrating a method for adjusting the optical axis of a LiDAR sensor using the optical axis adjustment system according to the second embodiment. [Modes for carrying out the invention]

[0013] In the following, identical or equivalent components and members shown in each drawing will be denoted by the same reference numeral, and redundant explanations will be omitted as appropriate. Furthermore, the dimensions of the members in each drawing will be enlarged or reduced as appropriate for ease of understanding. Additionally, some members that are not important for explaining the embodiment will be omitted from the drawings.

[0014] (First Embodiment) Figure 1 is a side view illustrating the optical axis adjustment system 100 according to the first embodiment. Figure 2 is a plan view illustrating the optical axis adjustment system 100 according to the first embodiment.

[0015] The optical axis adjustment system 100 adjusts the optical axis of the LiDAR sensor 10 mounted on the mobile body 102. The mobile body 102 is not particularly limited and may be, for example, an automated guided forklift (AGF) used in factories or warehouses. The LiDAR sensor 10 is positioned, for example, on the top of the mobile body 102.

[0016] The LiDAR sensor 10 is a sensor that measures the distance and direction to an object by irradiating it with a sensor laser beam SL, measuring the time it takes for the beam to bounce off the object and travel by car. The LiDAR sensor 10 may be a two-dimensional (2D) LiDAR sensor. In this embodiment, the LiDAR sensor 10 is used to measure the self-position of the moving object 102 in the space in which it is used. The self-position measurement technique using information obtained from the LiDAR sensor 10 is known as SLAM (Simultaneous Localization and Mapping). The laser light used by the LiDAR sensor 10 is invisible light such as near-infrared light.

[0017] In order to accurately measure its own position, it is necessary to set the optical axis of the LiDAR sensor 10 horizontally. The adjustment of the optical axis of the LiDAR sensor 10 by the optical axis adjustment system 100 is performed at a location having a flatness below a certain level. This is because if the optical axis is adjusted in the horizontal direction while the moving body 102 is tilted, the optical axis will be adjusted while maintaining the tilt of the floor at the adjustment site. Therefore, separately, for example, using a spirit level of 1 m or more, it is necessary to confirm that the flatness is below a certain level, for example, the difference in unevenness of the floor plane is 7 mm or less per 3 m, and then select a location for optical axis adjustment. Even at a location having such a flatness below a certain level, as shown in FIG. 1, the floor 110 of a factory or a warehouse undulates, and the moving body 102 may be configured to be tilted. Therefore, an operation of horizontally adjusting the optical axis of the LiDAR sensor 10 is required. The optical axis of the LiDAR sensor 10 can be adjusted by adjusting the pitch angle and roll angle of the LiDAR sensor 10.

[0018] As described above, since the laser light used by the LiDAR sensor 10 is non-visible light such as near-infrared light, an operator cannot directly view the horizontal laser beam HL emitted by the LiDAR sensor 10 to adjust the optical axis. By using the optical axis adjustment system 100 according to the present embodiment, the optical axis of the LiDAR sensor 10 can be adjusted with high precision and simply.

[0019] The optical axis adjustment system 100 for the LiDAR sensor 10 includes a horizontal laser irradiator 12 and a surveying rod 14.

[0020] The horizontal laser irradiator 12 is disposed at an arbitrary position in the space where the moving body 102 is used, for example, near the moving body 102. The horizontal laser irradiator 12 is supported by a support member 16 such as a tripod, for example. The horizontal laser irradiator 12 irradiates a horizontal laser beam HL at a predetermined height. The horizontal laser beam HL is visible light. The horizontal laser irradiator 12 may be capable of irradiating the horizontal laser beam HL 360 degrees around. As the horizontal laser irradiator 12, a commercially available laser marker can be used.

[0021] The measuring rod 14 is vertically arranged at a point at a predetermined distance D from the LiDAR sensor 10. In FIG. 2, a virtual circle C with a radius D centered on the LiDAR sensor 10 where the measuring rod 14 can be arranged is shown. The distance D is not particularly limited and may be, for example, 3 m. In FIGS. 1 and 2, the measuring rod 14 is arranged at the first point 30 on the virtual circle C.

[0022] As shown in FIG. 1, the measuring rod 14 is provided with a slider portion 18 that can move along its longitudinal direction. This slider portion 18 is provided with an alignment marker 20 for alignment with the horizontal laser beam HL and a laser detector 22 capable of detecting the sensor laser beam SL irradiated from the LiDAR sensor 10. The laser detector 22 is adjustable in position on the slider portion 18. The laser detector 22 has a light receiving surface in a predetermined range and can measure the height position of the sensor laser beam SL from the reference point (zero point). When the sensor laser beam SL is located above the reference point, the output value of the laser detector 22 becomes a positive value, and when the sensor laser beam SL is located below the reference point, the output value of the laser detector 22 becomes a negative value. As the laser detector 22, for example, the rotary laser receiver Rod Eye 160 manufactured by Leica Geosystems can be used.

[0023] FIG. 3 is a flowchart for explaining a method of adjusting the optical axis of the LiDAR sensor 10 using the optical axis adjustment system 100 according to the first embodiment.

[0024] In this optical axis adjustment method, first, the horizontal laser beam HL is irradiated at a predetermined height using the horizontal laser irradiator 12 (S10).

[0025] Next, the surveying rod 14 is positioned vertically at a first point 30 at a predetermined distance D from the LiDAR sensor 10 (S12). At the first point 30, the slider unit 18 is moved relative to the surveying rod 14 to align the horizontal laser beam HL with the alignment marker 20 of the slider unit 18 (S14). Then, at the first point 30, the laser detector 22 is positioned on the slider unit 18 so that the sensor laser beam SL coincides with the reference point of the laser detector 22 (S16).

[0026] Next, the surveying rod 14 is positioned vertically at the second point 32, which is point-symmetric to the first point 30 with respect to the LiDAR sensor 10 (S18). At the second point 32, the slider part 18 is moved relative to the surveying rod 14 to align the horizontal laser beam HL with the alignment marker 20 (S20). Then, at the second point 32, the height difference HD between the sensor laser beam SL and the reference point is measured using the laser detector 22 (S22). The height difference HD is the absolute value of the output value of the laser detector 22. For example, if the height position H2 of the sensor laser beam SL at the second point 32 is +15 mm, the height difference HD will be 15 mm. Also, for example, if the height position H2 is -5 mm, the height difference HD will be 5 mm.

[0027] Next, the optical axis of the LiDAR sensor 10 is angle-adjusted (S24) so ​​that the height position H2 of the sensor laser beam SL at the second point 32 is shifted towards the reference point by half the height difference HD (HD / 2). The angle of the optical axis of the LiDAR sensor 10 can be adjusted by adjusting the pitch angle and roll angle of the LiDAR sensor 10, as described above. For example, if the height position H2 of the sensor laser beam SL at the second point 32 is +15mm, then half the height difference HD is 15mm / 2 = 7.5mm, so the optical axis of the LiDAR sensor 10 is angle-adjusted so that the height position H2 of the sensor laser beam SL is shifted towards the reference point by 7.5mm from +15mm to +7.5mm. Furthermore, if the height position H2 of the sensor laser beam SL at the second point 32 is -5mm, then half of the height difference HD is 5mm / 2 = 2.5mm. Therefore, the optical axis of the LiDAR sensor 10 is angle-adjusted so that the height position H2 of the sensor laser beam SL shifts from -5mm towards the reference point by 2.5mm to -2.5mm.

[0028] After adjusting the angle in S24, the surveying rod 14 is again positioned vertically at the first point 30. At the first point, the slider part 18 is moved relative to 30 and the surveying rod 14 to align the horizontal laser beam HL with the alignment marker 20 (S28). Then, using the laser detector 22, it is confirmed that the height position H1 of the sensor laser beam SL at the first point 30 is shifted from the reference point by half the height difference HD (S30).

[0029] By performing steps S10 to S30 above, the optical axis of the LiDAR sensor 10 can be adjusted horizontally. While optical axis adjustment can also be performed from S10 to S24, performing the verification steps from S26 to S30 allows for more reliable optical axis adjustment.

[0030] As described above, the optical axis adjustment system 100 and optical axis adjustment method according to this first embodiment allow for high-precision optical axis adjustment of the LiDAR sensor 10 with a simple configuration consisting of a horizontal laser irradiator 12 and a measuring rod 14 equipped with a slider section 18.

[0031] (Second Embodiment) Figure 4 is a side view illustrating the optical axis adjustment system 200 according to the second embodiment.

[0032] The optical axis adjustment system 200 differs from the slider unit 18 in the first embodiment in the configuration of the slider unit 218 provided on the surveying rod 14. The slider unit 218 is provided with a marker 20 for alignment with the horizontal laser beam HL, and a reflectance changing unit 206 that changes the reflectance to the sensor laser beam SL emitted from the LiDAR sensor 10 by comparing the slider unit 218 with other parts of the surveying rod 14.

[0033] The reflectance changing section 206 may be a reflector that reflects the sensor laser beam SL, or it may be a light-absorbing member that absorbs the sensor laser beam SL. Alternatively, instead of a light-absorbing member, holes may be provided in the slider section 218 to suppress light reflection.

[0034] If the reflectance-changing section 206 is a reflector, the light intensity detected by the LiDAR sensor 10 will be higher than that of the slider section 218 and other parts of the measuring rod 14, so the presence of the reflectance-changing section 206 can be detected by the LiDAR sensor 10. Here, it is desirable to adjust the reaction threshold of the LiDAR sensor 10 so that it reacts to reflected light from the reflectance-changing section 206 but not to reflected light from the slider section 218 and other parts of the measuring rod 14 before performing the work. If the reflectance-changing section 206 is a light-absorbing material or if a hole is provided in the slider section 218, the light intensity detected by the LiDAR sensor 10 will be lower than that of the slider section 218 and other parts of the measuring rod 14, so the presence of the reflectance-changing section 206 can be detected by the LiDAR sensor 10.

[0035] In this embodiment, the reflectance changing section 206 includes a first reflectance changing section 202 having a height h1 smaller than the height h of the sensor laser beam SL that is permissible at a predetermined distance D from the LiDAR sensor 10, and a second reflectance changing section 204 having a height h2 equal to the height h. The height h of the sensor laser beam SL that is permissible at a predetermined distance D from the LiDAR sensor 10 is determined by the permissible angle θ of the sensor laser beam SL and the predetermined distance D, and can be expressed as D × tanθ. For example, if the permissible angle θ is 1° and the predetermined distance D is 3m, the height h is 52mm. Therefore, in this case, the height h2 of the second reflectance changing section 204 is 52mm, and the height h1 of the first reflectance changing section 202 is set to a value smaller than 52mm, for example, 42mm.

[0036] Furthermore, it is desirable to set the width of the reflectance-changing section 206 considering the resolution of the LiDAR sensor 10 and the spread of the light rays. Specifically, it is desirable that the width of the reflectance-changing section 206 be such that, at the resolution of the target LiDAR sensor 10, several or more points can be detected at a predetermined distance D from the LiDAR sensor 10 (for example, 50 mm or more).

[0037] The first reflectance changing section 202 and the second reflectance changing section 204 are arranged to face different directions (for example, 90° or 180° apart). Furthermore, the height h3 from the alignment marker 20 to the center of the first reflectance changing section 202 and the second reflectance changing section 204 coincides with the height h4 from the reference plane 10a of the LiDAR sensor 10 to the optical axis. The reference plane of the LiDAR sensor 10 may be, for example, the contact surface with the base bracket.

[0038] Figure 5 is a flowchart illustrating a method for adjusting the optical axis of a LiDAR sensor 10 using the optical axis adjustment system 200 according to the second embodiment.

[0039] In this optical axis adjustment method, first, a horizontal laser beam HL is irradiated using a horizontal laser irradiator 12 to the height of the reference plane 10a of the LiDAR sensor 10 (S110).

[0040] Next, the surveying rod 14 is positioned vertically at a first point 30 at a predetermined distance D from the LiDAR sensor 10 (S112). At the first point 30, the slider unit 18 is moved relative to the surveying rod 14 to align the horizontal laser beam HL with the alignment marker 20 of the slider unit 18 (S114).

[0041] Next, the optical axis of the LiDAR sensor 10 is angle-adjusted so that the first reflectance change section 202 can be detected by the LiDAR sensor 10 (S116). As described above, the height h3 from the alignment marker 20 to the center of the first reflectance change section 202 coincides with the height h4 from the reference plane 10a of the LiDAR sensor 10 to the optical axis. Therefore, if the optical axis of the LiDAR sensor 10 is within the allowable angle, a clear difference will appear in the light intensity detected by the LiDAR sensor 10 due to the light reflection or attenuation effect of the first reflectance change section 202. Based on this clear difference in light intensity, it is possible to determine whether or not the LiDAR sensor 10 can detect the first reflectance change section 202. To improve the workability of optical axis adjustment, it is also possible to notify the operator with sound or light when the first reflectance change section 202 is detected.

[0042] After adjusting the angle in S118, the surveying rod 14 is positioned vertically at the second point 32, which is point-symmetric to the first point 30 with respect to the LiDAR sensor 10 (S120). At the second point 32, the slider part 218 is moved relative to the surveying rod 14 to align the horizontal laser beam HL with the alignment marker 20 (S120). Then, at the second point 32, it is confirmed that the second reflectance change section 204 can be detected by the LiDAR sensor 10 (S122). If the optical axis adjustment at the first point 30 is done properly, the detection of the second reflectance change section 204 in S122 can be performed without any problems.

[0043] By performing steps S110 to S30 above, the optical axis of the LiDAR sensor 10 can be adjusted horizontally. While optical axis adjustment can also be performed from S110 to S116, performing the verification steps from S118 to S122 allows for more reliable optical axis adjustment.

[0044] As in this embodiment, by using two reflectance changing sections 206 with different heights, namely the first reflectance changing section 202 and the second reflectance changing section 204, an allowable tolerance can be set.

[0045] In another embodiment, instead of using two reflectance changing sections 206, optical axis adjustment can be performed using one first reflectance changing section 202 (the reflectance changing section with the smaller height). In this case, the optical axis adjustment needs to be more precise than when using two reflectance changing sections 206. This is because if the optical axis adjustment at the first point 30 is not precise, the confirmation of the first reflectance changing section 202 at the second point 32 may fail.

[0046] As described above, the optical axis adjustment system 200 and optical axis adjustment method according to this second embodiment also enable high-precision optical axis adjustment of the LiDAR sensor 10 with a simple configuration consisting of a horizontal laser irradiator 12 and a measuring rod 14 equipped with a slider section 18.

[0047] In the optical axis adjustment system 200 according to this second embodiment, the laser detector 22 used in the first embodiment is not required, thus reducing the cost of the system.

[0048] Any combination of the embodiments and modifications described above is also useful as an embodiment of the present invention. The new embodiments resulting from these combinations possess the combined effects of the respective embodiments and modifications. [Explanation of Symbols]

[0049] 10 LiDAR sensor, 12 horizontal laser irradiator, 14 measuring rod, 18 slider unit, 20 alignment marker, 22 laser detector, 30 first point, 32 second point, 100 optical axis adjustment system, 102 moving body, 200 optical axis adjustment system, 202 first reflectance change unit, 204 second reflectance change unit, 206 reflectance change unit, 218 slider unit.

Claims

1. A method for adjusting the optical axis of a LiDAR sensor, The steps include irradiating a horizontal laser beam at a predetermined height, A step of vertically positioning a measuring rod at a first point at a predetermined distance from the LiDAR sensor, wherein the measuring rod is provided with a slider portion that is movable along its longitudinal direction, the slider portion is provided with a marker for alignment with the horizontal laser beam, and a laser detector capable of measuring the height position of the sensor laser beam emitted from the LiDAR sensor, the laser detector being adjustable in position on the slider portion, and The first step is to move the slider part relative to the surveying rod at the first point to align the horizontal laser beam with the alignment marker, The first step is to adjust the position of the laser detector on the slider so that the sensor laser beam coincides with the reference point of the laser detector, The steps include positioning the surveying rod vertically at a second point that is point-symmetric to the first point with respect to the LiDAR sensor, The steps include: at the second point, moving the slider part relative to the surveying rod to align the horizontal laser beam with the alignment marker; The steps include: measuring the height difference between the sensor laser beam and the reference point at the second location using the laser detector; The steps include: adjusting the angle of the optical axis of the LiDAR sensor so that the height position of the sensor laser beam at the second point is shifted toward the reference point by half the height difference; A method for adjusting the optical axis, characterized by comprising the following features.

2. After performing the angle adjustment, the step is to position the surveying rod vertically again at the first point, The first step is to move the slider part relative to the surveying rod at the first point to align the horizontal laser beam with the alignment marker, The first step is to use the laser detector to confirm that the height position of the sensor laser beam is shifted from the reference point by half the height difference, The optical axis adjustment method according to claim 1, characterized by comprising the following:

3. A method for adjusting the optical axis of a LiDAR sensor, The steps include irradiating the LiDAR sensor with a horizontal laser beam at the height of the reference plane, A step of vertically positioning a measuring rod at a first point at a predetermined distance from the LiDAR sensor, wherein the measuring rod is provided with a slider portion that is movable along its longitudinal direction, the slider portion is provided with an alignment marker for the horizontal laser beam, and a reflectance changing portion that changes the reflectance to the sensor laser beam emitted from the LiDAR sensor by comparing it with the slider portion and other parts of the measuring rod, the reflectance changing portion having a height smaller than the height of the sensor laser beam allowed at the predetermined distance, and the height from the alignment marker to the center of the reflectance changing portion is equal to the height from the reference plane of the LiDAR sensor to the optical axis, The first step is to move the slider part relative to the surveying rod at the first point to align the horizontal laser beam with the alignment marker, The steps include adjusting the angle of the optical axis of the LiDAR sensor so that the reflectance change portion can be detected by the LiDAR sensor, A method for adjusting the optical axis, characterized by comprising the following features.

4. After performing the angle adjustment, the step is to position the surveying rod vertically at a second point that is point-symmetric to the first point with respect to the LiDAR sensor, The steps include: at the second point, moving the slider part relative to the surveying rod to align the horizontal laser beam with the alignment marker; A step to confirm that the reflectance change portion can be detected by the LiDAR sensor, The optical axis adjustment method according to claim 3, characterized by comprising the above.

5. The slider portion is further provided with a second reflectivity changing portion having the same height as the height of the sensor laser beam that is permissible at the predetermined distance. The second reflectance changing section is arranged to face a different direction from the reflectance changing section. In the angle adjustment step, the optical axis of the LiDAR sensor is angle-adjusted so that the second reflectance change portion can be detected by the LiDAR sensor. The optical axis adjustment method according to claim 4, characterized in that the confirmation step confirms that the second reflectance change portion can be detected by the LiDAR sensor.

6. A LiDAR sensor optical axis adjustment system, A horizontal laser irradiator that irradiates a horizontal laser beam at a predetermined height, A measuring rod positioned vertically at a predetermined distance from the LiDAR sensor, having a slider portion movable along its longitudinal direction, the slider portion being equipped with a marker for alignment with the horizontal laser beam, and a laser detector capable of measuring the height position of the sensor laser beam emitted from the LiDAR sensor, the laser detector being adjustable in position on the slider portion, and the measuring rod, An optical axis adjustment system characterized by comprising the following features.

7. A LiDAR sensor optical axis adjustment system, A horizontal laser irradiator that irradiates a horizontal laser beam at the height of the reference plane of the LiDAR sensor, A surveying rod positioned vertically at a predetermined distance from the LiDAR sensor, the surveying rod having a slider portion movable along its longitudinal direction, the slider portion having a marker for alignment with the horizontal laser beam, and a reflectance changing portion that changes the reflectance to the sensor laser beam emitted from the LiDAR sensor by comparing the slider portion and other parts of the surveying rod, the reflectance changing portion having a height smaller than the height of the sensor laser beam allowed at the predetermined distance, and the height from the alignment marker to the center of the reflectance changing portion being equal to the height from the reference plane of the LiDAR sensor to the optical axis, An optical axis adjustment system characterized by comprising the following features.

8. The slider portion is further provided with a second reflectivity changing portion having the same height as the height of the sensor laser beam that is permissible at the predetermined distance. The optical axis adjustment system according to claim 7, characterized in that the second reflectance changing section is arranged to face a direction different from that of the reflectance changing section.

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