Test device, test method of laser radar and speed measurement calibration method

Abstract

The invention provides a test device, a laser radar test method and a speed measurement calibration method. The testing device comprises a target piece and a driving assembly, wherein the target piece is provided with a reflection plane capable of reflecting laser; the driving assembly is connected with the target piece; the driving assembly is configured to drive the target piece to rotate around the first axis at a preset linear speed, the reflection plane is arranged parallel to the radial direction of the rotation path of the target piece, and in the rotation process of the target piece, the reflection plane can face a transceiving window of a to-be-detected laser radar with a fixed position. According to the testing device provided by the invention, the motion path of the target piece can be limited in the circumferential path, so that the occupied area of the whole testing device is relatively small under the condition that the target piece can rotate at the preset linear speed.

Description

Technical Field

[0001] This invention belongs to the field of lidar, specifically relating to a lidar testing device, a lidar testing method, and a lidar speed measurement calibration method. Background Technology

[0002] With the development of the automotive industry, the technical requirements for automotive LiDAR are becoming increasingly stringent. Frequency Modulated Continuous Wave (FMCW) LiDAR is gradually being adopted in vehicles due to its excellent speed measurement capabilities. Specifically, FMCW LiDAR can detect the relative velocity between itself and a target using the Doppler frequency shift principle. The Doppler frequency shift principle states that when there is a relative velocity between the target and the LiDAR, a frequency difference will occur between the frequency of the received echo laser signal and the frequency of the transmitted signal; by measuring this frequency difference, the relative velocity between the target and the LiDAR can be determined.

[0003] Before FMCW lidar is put into use, its speed measurement performance usually needs to be tested. To calibrate the speed of the FMCW lidar, a speed-adjustable reflective target is required. Vehicle-mounted lidar needs to test various moving targets with different speeds, such as pedestrians and cars, generally requiring the reflective target's speed range to be 0–300 km / h.

[0004] Currently, the traditional testing method involves placing the FMCW lidar under test on a moving car to measure the relative speed between it and a stationary object on the roadside as the car travels at a certain height; or mounting the lidar on the roadside to measure the relative speed between the lidar and a high-speed moving car. However, this method is limited by the available space, inconvenient to operate, and costly. Summary of the Invention

[0005] The present invention aims to solve the problem of the large footprint of existing lidar testing equipment, and provides a lidar testing device as well as a testing method and a velocity calibration method using the testing device.

[0006] This invention provides a testing device.

[0007] This device is used for testing the speed measurement function of a lidar under test, wherein the lidar under test is positioned fixed during the test; it includes a target component and a driving assembly; wherein the target component has a reflective plane capable of reflecting laser light;

[0008] The driving component is connected to the target component; the driving component is configured to drive the target component to rotate around a first axis at a preset linear velocity; the reflecting plane is arranged radially parallel to the rotation path of the target component, and during the rotation of the target component, the reflecting plane can face the transceiver window of the lidar under test.

[0009] Optionally, the drive assembly includes a power source and transmission components;

[0010] The power source is configured to output rotational power at a preset speed;

[0011] The transmission component is connected to the power source and the target component respectively to drive the transmission component to rotate around the first axis; the transmission component is configured to adjust the rotation radius of the target component, and the rotation radius of the target component satisfies that: when the transmission component rotates at the preset speed, the linear velocity of the target component can reach the preset linear velocity.

[0012] Optionally, the transmission component includes a drive turntable and a mounting bracket; wherein,

[0013] The drive turntable is coaxially arranged with the first axis and connected to the power output end of the power source, so that the drive turntable can rotate around the first axis.

[0014] One end of the mounting bracket is fixedly connected to the target component, and the reflective plane is arranged radially along the drive turntable; the drive turntable has a plurality of radially spaced mounting portions, and the other end of the mounting bracket is detachably connected to at least one of the plurality of mounting portions to adjust the distance between the target component and the first axis.

[0015] Optionally, the transmission component includes a first rotating shaft and a second rotating shaft; wherein,

[0016] The first rotating shaft is coaxial with the first axis and connected to the power output end of the power source, so that the first rotating shaft can rotate around the first axis.

[0017] The second rotating shaft is connected to the first rotating shaft and is arranged perpendicular to the first axis; the reflective plane is arranged along the axial direction of the second rotating shaft; the second rotating shaft has a retractable mounting end, which is connected to the target component.

[0018] Optionally, the testing apparatus may also include a fixing component;

[0019] The fixing component is configured to fix the lidar under test at a preset fixed position, and the preset fixed position satisfies that the emission path of the lidar under test is tangent to the rotation path of the target.

[0020] Optionally, the testing apparatus may also include a protective cover;

[0021] The protective cover covers the periphery of the target and the drive assembly; the protective cover is configured to allow laser light to pass through.

[0022] As another technical solution, the present invention also provides a testing method for lidar, employing the testing apparatus described above, which includes:

[0023] Control the target component to rotate around the first axis at a preset linear velocity;

[0024] The laser radar under test is controlled to measure the speed of the target component in order to obtain the detection speed;

[0025] Calculate the difference between the preset linear velocity and the detection velocity of the lidar under test, and determine whether the difference is within the expected error range;

[0026] If so, the lidar under test is deemed qualified.

[0027] Optionally, controlling the lidar under test to measure the speed of the target object includes:

[0028] The laser radar under test is controlled to continuously measure the speed for a specified duration to obtain a set of detection values; the specified duration is greater than or equal to the time required for the target to rotate one revolution.

[0029] The maximum value is obtained from the set of detected values ​​and used as the detection speed.

[0030] Or, including:

[0031] The rotation angle of the driving component is continuously acquired, and the angle between the reflecting plane and the emission path of the lidar under test is calculated based on the rotation angle of the driving component.

[0032] When the included angle is 90°, the laser radar under test is controlled to measure the speed to obtain the detection speed.

[0033] As another technical solution, the present invention also provides a speed measurement calibration method for lidar, which uses the testing device described above and includes the following steps performed cyclically:

[0034] Obtain a preset linear velocity within the preset linear velocity range;

[0035] The target component is controlled to rotate around the first axis at the preset linear velocity;

[0036] Control the lidar to be calibrated to measure the speed of the target component;

[0037] The detection signal emitted by the lidar to be calibrated is acquired, and the corresponding preset linear velocity is used as the calibration velocity.

[0038] Optionally, the driving component of the testing device includes a power source and a transmission component; the power source is configured to output rotational power; the transmission component is configured to drive the transmission component to rotate around the first axis and is capable of adjusting the rotation radius of the target component;

[0039] The speed measurement calibration method also includes:

[0040] Obtain the velocity measurement period of the lidar to be calibrated;

[0041] Calculate the speed measurement distance based on the preset linear velocity and the speed measurement period;

[0042] The rotation radius of the target component is calculated based on the measured speed distance.

[0043] The preset rotational speed of the power source is calculated based on the rotation radius and the preset linear velocity.

[0044] Optionally, the rotation radius of the target component is greater than or equal to 50 times the speed measuring distance.

[0045] Optionally, after calculating the rotation radius of the target component, the method further includes:

[0046] Adjust the position of the target component relative to the first axis so that the distance between them is the radius of rotation.

[0047] The present invention has the following beneficial effects:

[0048] The testing apparatus provided in this invention includes a target component and a driving assembly for driving the target component to rotate. Specifically, the driving assembly is configured to drive the target component to rotate around a first axis at a preset linear velocity for detection by a lidar under test. The speed measurement performance of the lidar under test can then be determined by comparing the preset linear velocity with the detection result. Furthermore, the driving assembly proposed in this invention can restrict the motion path of the target component to a circular path, thereby reducing the footprint of the entire testing apparatus while ensuring the target component can rotate at the preset linear velocity.

[0049] Furthermore, as the target component rotates with the drive assembly, it can rotate until its reflective plane faces the fixed-position transceiver window of the lidar under test. This prevents the laser signal from being obliquely reflected at the reflective surface, thereby increasing the proportion of the echo laser signal returning along the original path in the echo laser signal. Consequently, the speed detected by the lidar under test can be made as close as possible to the actual speed of the target component, thus improving the test accuracy. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of a test device for a lidar provided in an embodiment of the present invention;

[0051] Figure 2 A schematic diagram of another testing device for lidar provided in an embodiment of the invention;

[0052] Figure 3 for Figure 2 A top view of the test setup for the lidar shown;

[0053] Figure 4 A schematic diagram illustrating the positional relationship between the target component and the lidar in the testing apparatus provided for an embodiment of the invention;

[0054] Figure 5A A velocity decomposition diagram of a target component during rotation, provided for an embodiment of the invention;

[0055] Figure 5B Another velocity decomposition diagram of the target component during rotation process provided for an embodiment of the invention;

[0056] Figure 5C A schematic diagram illustrating another velocity decomposition during the rotation process of the target component, provided for an embodiment of the invention;

[0057] Figure 6 A flowchart illustrating the testing method for lidar provided in an embodiment of the present invention;

[0058] Figure 7 A flowchart illustrating the calibration method for a lidar provided in an embodiment of the present invention. Detailed Implementation

[0059] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] It is understood that the specific embodiments and accompanying drawings described herein are merely for explaining the invention and are not intended to limit the invention.

[0061] It is understood that, without conflict, the various embodiments of the present invention and the features thereof can be combined with each other.

[0062] It is understood that, for ease of description, the accompanying drawings of this invention only show the parts related to the embodiments of this invention, while the parts unrelated to the embodiments of this invention are not shown in the drawings.

[0063] It is understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of the embodiments of the present invention may occur in a different order than that marked in the accompanying drawings.

[0064] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

[0065] Example 1

[0066] Please refer to Figure 1 This embodiment provides a testing device for a lidar, used to test the speed measurement function of the lidar. The testing device includes a target component 1 and a driving component 2.

[0067] The target component 1 has a reflective surface capable of reflecting laser light. Specifically, the material of the reflective surface can be determined according to the application scenario of the lidar under test 3; for example, if the lidar under test 3 is used as a vehicle-mounted radar, the material of the reflective surface can be Lambertian board, metal, cement, wood, etc., to simulate objects with different reflectivities on the road surface, so that the test results are more applicable to actual application scenarios.

[0068] The driving component 2 is connected to the target component 1 and is used to drive the target component 1 to move so that the lidar under test 3 can detect the target component 1. By comparing the speed of the target component 1 with the detection result of the lidar under test 3, it can be determined whether the speed measurement performance of the lidar under test 3 meets the standard. Specifically, the driving component 2 is configured to drive the target component 1 to rotate around the first axis L1 at a preset linear velocity. This restricts the movement path of the target component 1 to a circular path, thereby reducing the footprint of the entire testing device while ensuring that the target component 1 can rotate at the preset linear velocity. In other words, under the condition of limited footprint, the testing device proposed in this embodiment can increase the upper limit of the testing speed range. It should be noted that during the above testing process, the position of the lidar under test 3 is fixed to reduce the footprint required to place the lidar under test 3 and to ensure that the relative speed between the lidar under test 3 and the target component 1 depends only on the speed of the target component 1, thus avoiding interference from the speed of the lidar under test 3 itself on the detection result, thereby reducing the difficulty of data analysis of the detection result.

[0069] like Figure 4 As shown, the reflective plane of target component 1 is arranged radially parallel to the rotation path of target component 1. Thus, during the rotation of target component 1, the reflective plane remains perpendicular to the direction of movement of target component 1. Furthermore, the positional relationship between target component 1 and the lidar under test 3 satisfies the following condition: during the rotation of target component 1, its reflective plane can face the transceiver window of lidar under test 3. When the reflective plane faces the transceiver window, most of the echo laser signal can be reflected back to the transceiver window of lidar under test 3 after reaching the reflective plane. In addition, since the reflective plane is planar and always perpendicular to the direction of movement of target component 1, the laser signal emitted by the lidar is less prone to deviation or divergence after being reflected by the reflective plane. This further reduces the deviation of the echo laser signal from the transceiver window of lidar under test 3, increases the proportion of echo laser signal returning along the original path, and allows the speed detected by lidar under test 3 to be as close as possible to the actual speed of target component 1, thereby improving the accuracy of the speed measurement performance test for lidar under test 3.

[0070] It should be noted that, ideally, the "reflecting plane facing the transceiver window of the lidar under test" mentioned in this application refers to the position where the reflecting plane reaches a position perpendicular to the transmission path of the lidar under test 3. However, in practical applications, due to installation errors and interference factors such as airflow in the site, which are difficult to avoid, this application also allows the reflecting plane to have a slight deflection relative to the transmission path of the lidar under test 3 when it reaches the position facing the transceiver window of the lidar under test. For example, it can be deflected by 0° to 5°.

[0071] Furthermore, in some embodiments, the testing apparatus further includes a fixing component (not shown in the figure), which is configured to fix the lidar under test 3 at a preset fixed position, wherein the preset fixed position satisfies that the emission path of the lidar under test 3 is tangent to the rotation path of the target 1. Thus, when the reflective plane of the target 1 faces the transceiver window of the lidar under test 3, the laser signal emitted by the lidar under test 3 can be perpendicular to the reflective plane, and the echo laser signal can also return to the transceiver window of the lidar under test 3 in a direction perpendicular to the reflective plane.

[0072] It should be noted that lidar can only measure velocities parallel to the laser direction; and since target 1 only rotates around the first axis L1, and the lidar 3 under test maintains a fixed position, therefore, if... Figure 4 As shown, the direction of motion of target 1 is not always parallel to the laser direction, and the laser signal emitted by the laser radar 3 under test does not always illuminate the reflector at a perpendicular angle. Instead, the angle between the reflecting plane and the laser signal path changes from an acute angle to a right angle and then to an obtuse angle. Therefore, as Figures 5A-5CAs shown, according to the principle of velocity decomposition, the linear velocity of target 1 can be decomposed into a velocity V1 parallel to the laser signal path and a component velocity V2 perpendicular to velocity V1. Component velocity V1 is the detection velocity detected by the lidar 3 under test. Figures 5A-5C As shown, as target 1 rotates, the speed V1 detected by the lidar will increase and then decrease again; among which, as Figure 5B As shown, at the moment when the reflecting plane is perpendicular to the laser signal path, the velocity V1 is equal to the preset linear velocity V0. Moreover, at this moment, the detection velocity detected by the lidar under test 3 reaches its maximum. Therefore, the maximum value of the velocity detected by the lidar under test 3 can be taken as the final detection result of the lidar under test 3, so that the detection velocity detected by the lidar under test 3 is as close as possible to the preset linear velocity, thereby minimizing the detection error.

[0073] In some embodiments, such as Figure 1 and Figure 2 As shown, the drive assembly 2 includes a power source 21 and a transmission component. The power source 21 is configured to output rotational power at a preset rotational speed. The transmission component is connected to both the power source 21 and the target component 1 to drive the transmission component to rotate around a first axis L1. The transmission component is configured to adjust the rotation radius of the target component 1, which satisfies the following condition: when the transmission component rotates at a preset rotational speed, the linear velocity of the target component 1 can reach a preset linear velocity, so that the speed of the target component 1 reaches the preset linear velocity. Specifically, in circular motion, the linear velocity is equal to 2π times the product of the rotation radius and the rotational speed. Therefore, the speed of the target component 1 can be adjusted by adjusting the preset rotational speed of the power source 21 and the rotation radius of the target component 1. Accordingly, 2π times the product of the rotation radius of the target component 1 and the preset rotational speed should be equal to the preset linear velocity.

[0074] In some preferred embodiments, the drive source described above may be a servo motor with adjustable speed.

[0075] Based on the above principle, the preset linear velocity range is 2π times the product of the rotational speed range of the power source 21 and the rotational radius range of the target component 1. For example, if the power source 21 uses a servo motor with a rotational speed range of 0–1600 rpm and the rotational radius range of the target component 1 is 0–0.5 m, then the preset linear velocity range is 0–300 km / h. Correspondingly, the test speed range of the testing device can reach 0–300 km / h, which can meet the testing requirements for the speed measurement function of vehicle-mounted LiDAR. In comparison, traditional vehicle-mounted LiDAR testing equipment typically requires tens or even hundreds of square meters of floor space. Therefore, the testing equipment proposed in this embodiment can significantly reduce the floor space required for vehicle-mounted LiDAR testing.

[0076] In some specific embodiments, before the test begins, the aforementioned fixed component can be movable relative to the driving component 2, while the driving component 2 remains fixed; or, the driving component 2 can be movable relative to the fixed component, while the fixed component remains fixed; or, both the fixed component and the driving component 2 can be movable relative to each other, so that the port of the lidar under test 3 can be positioned on the tangent of the rotation path of the target component 1 by making them movable relative to each other. Furthermore, the driving component 2 and the fixed component can be movable relative to each other in the direction of the first axis L1 and in the direction of the rotation diameter of the target component 1, so that when the target component 1 rotates to a position opposite to the lidar under test 3, the transceiver window of the lidar is aligned as much as possible with the reflecting plane.

[0077] In some specific embodiments, such as Figure 1 As shown, the aforementioned transmission components include a drive turntable 22 and a mounting bracket 23. The drive turntable 22 is coaxially arranged with the first axis L1 and connected to the power output end of the power source 21, enabling the drive turntable 22 to rotate around the first axis L1. One end of the mounting bracket 23 is fixedly connected to the target component 1, and its reflective plane is arranged radially along the drive turntable 22, ensuring that the reflective plane is always perpendicular to the tangent of the rotation path during the rotation of the target component 1. The drive turntable 22 has multiple radially spaced mounting portions; the other end of the mounting bracket 23 is detachably connected to at least one of these mounting portions, allowing adjustment of the distance between the target component 1 and the first axis L1 by switching the position of the mounting bracket 23, thereby adjusting the rotation radius of the target component 1.

[0078] In some specific embodiments, the mounting portion can be a mounting hole for inserting the mounting bracket 23, thereby adjusting the rotation radius of the target component 1 by inserting the mounting bracket 23 into different mounting holes.

[0079] In some specific embodiments, such as Figure 1 As shown, there are multiple target components 1. Correspondingly, there are also multiple mounting brackets 23. Moreover, the multiple mounting holes are symmetrically arranged around the first axis L1, so that multiple target components 1 can be fixed symmetrically on the drive turntable 22. This allows the same lidar under test 3 to measure the speed of multiple target components 1 with different reflective surfaces, or it can also test the speed measurement function of multiple lidar under test 3.

[0080] In some specific embodiments, the drive turntable 22 can be placed horizontally so that the surface of the drive turntable 22 is set in the horizontal direction, thereby avoiding the interference of gravity on the rotation speed of the target part 1.

[0081] In some feasible embodiments, the drive turntable 22 can also be placed vertically so that the surface of the drive turntable 22 is set in the vertical direction. For example, the drive turntable 22 can be installed on a vertical wall to save space.

[0082] In other embodiments, such as Figure 2 and Figure 3 The transmission components shown include a first rotating shaft 24 and a second rotating shaft 25. The first rotating shaft 24 is coaxial with the first axis L1 and connected to the power output end of the power source 21, enabling it to rotate around the first axis L1. The second rotating shaft 25 is connected to the first rotating shaft 24 and is perpendicular to the first axis L1; the reflecting plane is parallel to the axial direction of the second rotating shaft 25. Thus, during the rotation of the target component 1, the reflecting plane is always perpendicular to the tangent of the rotation path, allowing it to reach a position perpendicular to the laser signal path when the reflecting plane of the target component 1 faces the transceiver window of the laser radar 3 under test.

[0083] The second rotating shaft 25 has a retractable mounting end 251, which is connected to the target part 1. By extending or retracting the mounting end 251 along the axial direction of the second rotating shaft 25, the distance between the target part 1 and the first axis L1 can be adjusted, thereby adjusting the rotation radius of the target part 1. Furthermore, when the testing device is not performing tests, the mounting end 251 can be retracted to the position closest to the first axis L1, so that the length of the second rotating shaft 25 is shortened as much as possible, thereby saving storage space for the testing device.

[0084] Specifically, the connection between the mounting end 251 and the target part 1 can be achieved by plug-in connection, threaded connection or clamping connection.

[0085] In some specific embodiments, such as Figure 2 and Figure 3 As shown, there are two target components 1. Correspondingly, there are also two mounting ends 251 of the second rotating shaft 25, so that the two target components 1 can be symmetrically arranged on both sides of the first axis L1. Alternatively, there can be more than two target components 1, so that multiple target components 1 can be symmetrically fixed on multiple mounting ends 251 with the first axis L1 as the center. This allows the same lidar under test 3 to measure the speed of multiple target components 1 with different reflective surfaces, or it can also test the speed measurement function of multiple lidar under test 3.

[0086] Alternatively, in other embodiments, the second rotating shaft 25 may be multiple non-extendable shafts of different lengths, so that the rotation radius of the target component 1 can be adjusted by replacing the second rotating shaft 25 of different lengths.

[0087] In some specific embodiments, the first rotating shaft 24 described above can be placed horizontally or vertically.

[0088] In some embodiments, the distance from the mounting bracket 23 to the first axis L1 and the distance from the mounting end 251 of the second rotating shaft 25 to the first axis L1 are greater than or equal to 50 times the distance traveled by the target component 1 within the speed measurement cycle, so that the rotation radius of the target component 1 is greater than or equal to 50 times the distance traveled within the speed measurement cycle. The speed measurement cycle of the lidar is the time interval from the emission of the laser signal to the receipt of a complete echo laser signal containing speed information. Specifically, the speed measurement cycle of the lidar is extremely short, therefore the distance traveled by the target component 1 within one speed measurement cycle is also extremely short. Taking an FMCW lidar as an example, its speed measurement cycle is typically 10–100 μs; when the linear velocity of the target component 1 reaches 300 km / h, its distance traveled within one speed measurement cycle is 0.8–8 mm. In this case, the rotation radius of the target component 1 is, for example, 0.5 m, which is much larger than the distance traveled by the target component 1. It can be seen that the circular motion of the target component 1 within the speed measurement cycle can be approximated as linear motion, thereby minimizing the error caused by non-radial motion, or even making it negligible, thus improving the test accuracy.

[0089] It is easy to understand that in actual testing, different radii can be selected based on the requirements for speed measurement accuracy and the space occupied.

[0090] In some embodiments, the testing apparatus further includes a protective cover (not shown in the figure). The protective cover is configured to allow laser light to pass through and covers the periphery of the target 1 and the drive assembly 2, so as to protect the structure of the drive assembly 2 and the target 1 while ensuring that the laser signal can reach the reflective surface and the echo laser signal can reach the transceiver window of the lidar under test 3, and to prevent the target 1 or the transmission mechanism from being thrown out during rotation, thereby avoiding the occurrence of safety accidents.

[0091] In some specific embodiments, the protective cover can be a mesh cover with mesh openings sufficient for a laser to pass through. Alternatively, the protective cover can be a light-transmitting glass cover; furthermore, the glass cover can also form a sealed space, so that the target part 1 can be prevented from being subjected to air resistance during rotation by evacuating the sealed space, thereby eliminating the interference of air resistance on the test accuracy, and increasing the upper limit of the speed of the target part 1, thereby increasing the upper limit of the test speed range.

[0092] The testing device provided in this embodiment drives a target component to rotate at a preset linear velocity for detection by the lidar under test. This restricts the target component's motion path to a circular path, thus minimizing the overall footprint of the testing device while ensuring the target component can rotate at the preset linear velocity. Furthermore, the target component in this embodiment has a reflective plane that faces the transceiver window of the lidar under test, increasing the proportion of the echo laser signal returning along the original path, thereby improving the accuracy of velocity measurement tests on the lidar under test.

[0093] Example 2

[0094] Based on the testing apparatus proposed in Embodiment 1, this embodiment provides a testing method for a lidar, used to test the speed measurement function of a calibrated lidar. Referring to Figure 5, the testing method includes:

[0095] S01: Control the target component 1 to rotate around the first axis L1 at a preset linear velocity;

[0096] S02: Control the laser radar 3 under test to measure the speed of the target 1 in order to obtain the detection speed;

[0097] S03: Calculate the difference between the preset linear velocity and the detection velocity of the lidar 3 under test, and determine whether the difference is within the expected error range; if yes, the lidar 3 under test is qualified; if no, the lidar 3 under test is unqualified.

[0098] Specifically, the above-mentioned expected error range can be set according to the actual accuracy requirements of the lidar.

[0099] As mentioned above, the lidar can only measure velocities parallel to the laser direction. Furthermore, as the target 1 rotates, the angle between the reflective plane and the emission path of the lidar 3 will increase and then decrease again. Therefore, the maximum velocity detected by the lidar is the velocity at the moment when the reflective plane is perpendicular to the laser signal path. Since the reflective plane is radially positioned along the rotation path of the target 1, the velocity at the moment when the reflective plane is perpendicular to the laser signal path is the preset linear velocity. Based on this principle, in some embodiments, step S02 may include the following steps:

[0100] S021a: Control the laser radar under test 3 to continuously measure the speed for a specified duration to obtain a set of detection values; wherein, the specified duration is greater than or equal to the time required for the target to rotate one revolution, so that the laser radar under test 3 can detect the speed at the moment when the reflecting plane is perpendicular to the laser signal path, thereby making the detection speed as close as possible to the preset linear speed to ensure the accuracy of the detection results;

[0101] S022a: Obtain the maximum value in the set of detected values ​​and use it as the detection speed.

[0102] Alternatively, step S02 above may also include the following steps:

[0103] S021b: Continuously acquire the rotation angle of the drive component 2, and calculate the angle between the reflective plane and the emission path of the lidar under test 3 based on the rotation angle of the drive component 2;

[0104] Specifically, step S021b can utilize the servo motor's self-rotation angle monitoring function in drive component 2 to obtain the aforementioned rotation angle from the servo motor's own control module.

[0105] S022b: When the included angle is 90°, control the laser radar 3 under test to perform speed measurement to obtain the detection speed; that is, measure the speed at the moment when the reflection plane is perpendicular to the laser signal path, so that the detection speed is as close as possible to the preset linear speed to ensure the accuracy of the detection results.

[0106] Furthermore, based on the above testing apparatus, please refer to... Figure 6 This embodiment also provides a speed measurement calibration method for lidar, used to calibrate the speed measurement function of an uncalibrated lidar. The testing method includes:

[0107] S11: Obtain a preset linear velocity within the preset linear velocity range;

[0108] S12: Control the target component 1 to rotate around the first axis L1 at the preset linear velocity obtained in step S11;

[0109] S13: Control the lidar to be calibrated to measure the speed of target component 1;

[0110] Specifically, in some feasible embodiments, step S13 can be performed by measuring the speed of the target component 1 using steps S021a-S022a or steps S021b-S022b described above.

[0111] S14: Acquire the detection signal emitted by the lidar to be calibrated, and use the corresponding preset linear velocity as the calibration velocity.

[0112] By repeatedly performing steps S11-S14, the calibration of the lidar to be calibrated can be completed. It is easy to understand that the preset linear velocities obtained in each of the multiple iterations will be different.

[0113] Specifically, after obtaining multiple calibration speeds, the multiple detection signals and multiple calibration speeds can be stored one-to-one in the LiDAR's built-in memory or in an external data processing device in the form of data tables or data pointers. In the actual speed measurement process, the calibration speed corresponding to the actual detection signal of the LiDAR can be called as the detection value and sent to an external display device for the user to view, or sent to an external data processing device to process the detection value.

[0114] Please refer to Figure 4 In some embodiments, the testing method further includes a step of calculating the setting parameters of the testing apparatus, specifically including the following steps:

[0115] S111: Obtain the velocity measurement period t of the lidar to be calibrated;

[0116] Specifically, the velocity measurement period of a lidar is the time interval from the emission of the laser signal to the receipt of a complete echo laser signal containing velocity information; taking FMCW lidar as an example, its velocity measurement period is usually 10 to 100 μs.

[0117] S112: Calculate the speed measurement distance s based on the preset linear velocity v and the speed measurement period t;

[0118] Specifically, the speed measurement distance is the distance traveled by the target component 1 at a preset linear velocity for one speed measurement cycle; that is, s = v × t;

[0119] S113: Calculate the rotation radius r of target component 1 based on the measured distance s;

[0120] Specifically, the rotation radius r of the target component 1 is greater than or equal to 50 times the speed measuring distance. As mentioned above, setting the rotation radius r of the target component 1 to be greater than or equal to 50 times the speed measuring distance can make the rotation radius r much larger than the speed measuring distance s, so that the motion of the target component 1 can be approximated as linear motion.

[0121] Furthermore, after step S113, the method further includes: adjusting the position of the target component 1 relative to the first axis L1 so that the distance between them is the aforementioned rotation radius r; specifically, the rotation radius r can be adjusted by extending or retracting the mounting end 251 of the second rotating shaft 25, or by adjusting the position of the mounting bracket 23 on the drive turntable 22.

[0122] S114: Calculate the preset rotational speed n of power source 21 based on the rotation radius r and the preset linear velocity v;

[0123] Specifically, the preset rotational speed n of the power source 21 can be determined according to the formula for circular motion: And the calculations show that...

[0124] Furthermore, after step S114, the method further includes setting the output speed of the drive source to the calculated preset speed n.

[0125] The above-described testing and calibration methods for lidar provided in this embodiment can utilize the testing device provided in Embodiment 1 to test the speed measurement function of a calibrated lidar to determine its qualification, and to calibrate the speed measurement function of an uncalibrated lidar. Furthermore, it can reduce the area required for the testing and calibration processes and improve the accuracy of the test and calibration results.

[0126] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A testing device for testing the speed measurement function of a lidar under test, wherein the lidar under test is positioned fixed during the testing process; characterized in that, It includes a target component and a driving assembly; wherein the target component has a reflective plane capable of reflecting laser light; The driving component is connected to the target component; the driving component is configured to drive the target component to rotate around a first axis at a preset linear velocity; the reflecting plane is arranged radially parallel to the rotation path of the target component, and during the rotation of the target component, the reflecting plane can face the transceiver window of the lidar under test.

2. The testing apparatus according to claim 1, characterized in that, The drive assembly includes a power source and transmission components; The power source is configured to output rotational power at a preset speed; The transmission component is connected to the power source and the target component respectively to drive the transmission component to rotate around the first axis; the transmission component is configured to adjust the rotation radius of the target component, and the rotation radius of the target component satisfies that: when the transmission component rotates at the preset speed, the linear velocity of the target component can reach the preset linear velocity.

3. The testing apparatus according to claim 2, characterized in that, The transmission component includes a drive turntable and a mounting bracket; wherein... The drive turntable is coaxially arranged with the first axis and connected to the power output end of the power source, so that the drive turntable can rotate around the first axis. One end of the mounting bracket is fixedly connected to the target component, and the reflective plane is arranged radially along the drive turntable; the drive turntable has a plurality of radially spaced mounting portions, and the other end of the mounting bracket is detachably connected to at least one of the plurality of mounting portions to adjust the distance between the target component and the first axis.

4. The testing apparatus according to claim 2, characterized in that, The transmission component includes a first rotating shaft and a second rotating shaft; wherein... The first rotating shaft is coaxial with the first axis and connected to the power output end of the power source, so that the first rotating shaft can rotate around the first axis. The second rotating shaft is connected to the first rotating shaft and is arranged perpendicular to the first axis; the reflective plane is arranged along the axial direction of the second rotating shaft; the second rotating shaft has a retractable mounting end, which is connected to the target component.

5. The testing apparatus according to claim 1, characterized in that, It also includes fixed components; The fixing component is configured to fix the lidar under test at a preset fixed position, and the preset fixed position satisfies that the emission path of the lidar under test is tangent to the rotation path of the target.

6. The testing apparatus according to claim 1, characterized in that, It also includes a protective shield; The protective cover covers the periphery of the target and the drive assembly; the protective cover is configured to allow laser light to pass through.

7. A testing method for lidar, employing the testing apparatus as described in any one of claims 1-6, characterized in that, include: Control the target component to rotate around the first axis at a preset linear velocity; The laser radar under test is controlled to measure the speed of the target component in order to obtain the detection speed; Calculate the difference between the preset linear velocity and the detection velocity of the lidar under test, and determine whether the difference is within the expected error range; If so, the lidar under test is deemed qualified.

8. The test method according to claim 7, characterized in that, The control of the laser radar under test to measure the speed of the target object includes: The laser radar under test is controlled to continuously measure the speed for a specified duration to obtain a set of detection values; the specified duration is greater than or equal to the time required for the target to rotate one revolution. The maximum value is obtained from the set of detected values ​​and used as the detection speed. Or, including: The rotation angle of the driving component is continuously acquired, and the angle between the reflecting plane and the emission path of the lidar under test is calculated based on the rotation angle of the driving component. When the included angle is 90°, the laser radar under test is controlled to measure the speed to obtain the detection speed.

9. A method for calibrating the velocity of a lidar, employing the testing apparatus as described in any one of claims 1-6, characterized in that, This includes the following steps performed cyclically: Obtain a preset linear velocity within the preset linear velocity range; The target component is controlled to rotate around the first axis at the preset linear velocity; Control the lidar to be calibrated to measure the speed of the target component; The detection signal emitted by the lidar to be calibrated is acquired, and the corresponding preset linear velocity is used as the calibration velocity.

10. The speed measurement calibration method according to claim 9, characterized in that, The driving component of the testing device includes a power source and a transmission component; the power source is configured to output rotational power; the transmission component is configured to drive the transmission component to rotate around the first axis and is capable of adjusting the rotation radius of the target component; The speed measurement calibration method also includes: Obtain the velocity measurement period of the lidar to be calibrated; Calculate the speed measurement distance based on the preset linear velocity and the speed measurement period; The rotation radius of the target component is calculated based on the measured speed distance. The preset rotational speed of the power source is calculated based on the rotation radius and the preset linear velocity.

11. The speed measurement calibration method according to claim 10, characterized in that, The rotation radius of the target component is greater than or equal to 50 times the speed measuring distance.

12. The speed measurement calibration method according to claim 10, characterized in that, After calculating the rotation radius of the target component, the method further includes: Adjust the position of the target component relative to the first axis so that the distance between them is the radius of rotation.

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