Laser radar test method and laser radar test system

Abstract

The invention relates to a laser radar test method and a laser radar test system. The laser radar test system comprises a laser radar calibration trolley, a coarse adjustment system, a first fine adjustment system, a main support, a test system and a laser positioning system, the first fine adjustment system comprises a leveling mechanism and a fine adjustment mechanism, the fine adjustment mechanism is arranged on a lifting mechanism through the leveling mechanism, and the test system comprises a total station and a test rotary table. The laser positioning system comprises a telescope and three laser range finders which are arranged on the main bracket; the target plate trolley comprises a second fine adjustment system, a support frame, a reflecting plate and a calibration plate; and the radar calibration system comprises an upper computer, and the upper computer is used for controlling the laser radar calibration trolley and the target plate trolley so as to respectively adjust the pose of the laser positioning system and the pose of the calibration plate, so that the normal of the reflecting plate is aligned with the transmitting direction of the laser radar to be measured. According to the invention, the long-distance and high-precision performance test of the laser radar can be realized, and the repeatability of the test result is ensured.

Description

Technical Field

[0001] The present invention relates to the field of laser radar testing technology, and in particular to a laser radar testing method and a laser radar testing system. Background Art

[0002] As a high-precision environmental perception device, LiDAR is widely used in areas such as autonomous driving and smart transportation. Its detection performance (such as maximum detection range, ranging accuracy, and angular resolution) directly affects application reliability. Currently, LiDAR performance testing mainly relies on standard diffuse reflectors as targets, using two main technical approaches:

[0003] Indoor static field testing: A diffuse reflector is mounted on a linear guide rail, with the lidar fixed to one end. This solution is limited by the site size and cannot achieve long-distance testing of hundreds of meters. Furthermore, linearity errors on long guide rails accumulate over distance, resulting in reduced target alignment accuracy and distorted test results.

[0004] Outdoor field testing: Placing diffuse reflectors in open areas can meet long-distance requirements, but lacks high-precision relative position measurement. Manual adjustment of the normal line between the reflector and the lidar is required, and true reference values ​​for distance and angle cannot be obtained. This results in poor test repeatability and an inability to quantify measurement errors.

[0005] In summary, the existing technology has the problem of "not being able to measure far" or "not being able to measure accurately", and there is an urgent need for a system and method that can achieve long-distance, high-precision and high-repeatability testing. Summary of the Invention

[0006] In response to the above-mentioned problems in the prior art, the present invention proposes a lidar testing method and a lidar testing system, which can realize long-distance, high-precision performance testing of lidar and ensure the repeatability of test results.

[0007] Specifically, the present invention proposes a laser radar test system, comprising:

[0008] A laser radar calibration trolley includes a coarse adjustment system, a first fine adjustment system, a main support, a test system, and a laser positioning system. The coarse adjustment system includes a lifting mechanism and a support assembly disposed at the bottom of the lifting mechanism. The first fine adjustment system includes a leveling mechanism and a fine adjustment mechanism. The fine adjustment mechanism is disposed on the lifting mechanism via the leveling mechanism. The main support is fixed to the first fine adjustment system. The test system includes a total station and a test turntable disposed on the main support. The test turntable is suitable for mounting a laser radar to be tested. The leveling mechanism levels the main support via the total station. The laser positioning system includes a telescope and three laser rangefinders. The laser positioning system is disposed on the main support.

[0009] A target plate trolley comprises a second fine adjustment system, a support frame, a reflective plate and a calibration plate, wherein the support frame is arranged on the second fine adjustment system, the reflective plate is fixed on the support frame, and the calibration plate is suitable for being fixed to the support frame to cover the reflective plate;

[0010] The radar calibration system includes a host computer, which is used to control the laser radar calibration cart and the target board cart. The host computer fine-tunes the position of the laser positioning system through the first fine-tuning system, and adjusts the position of the calibration board through the second fine-tuning system to align the normal of the reflector with the emission direction of the laser radar to be measured.

[0011] According to one embodiment of the present invention, the support assembly includes a first movable roller and a first retractable support leg, the laser radar calibration trolley is moved to the test position by the first movable roller, the height of the first retractable support leg is adjustable, and the first retractable support leg is lowered to fix the laser radar calibration trolley in the test position;

[0012] The lifting mechanism is used to adjust the height of the laser positioning system so that the heights of the laser positioning system and the reflective plate are aligned.

[0013] According to one embodiment of the present invention, the fine adjustment mechanism includes a Z-axis fine adjustment mechanism, an X / Y-axis fine adjustment mechanism, and an RZ-axis fine adjustment mechanism, wherein the Z-axis fine adjustment mechanism is arranged on top of the lifting mechanism, the X / Y-axis fine adjustment mechanism is arranged on top of the Z-axis fine adjustment mechanism, and the RZ-axis fine adjustment mechanism is arranged on top of the X / Y-axis fine adjustment mechanism;

[0014] The Z-axis fine-tuning mechanism is used to fine-tune the height position of the laser positioning system in the vertical direction, the X / Y-axis fine-tuning mechanism is used to fine-tune the position of the X-axis and Y-axis of the laser positioning system in the horizontal direction, and the RZ-axis fine-tuning mechanism is used to adjust the horizontal rotation angle of the laser positioning system.

[0015] According to one embodiment of the present invention, the laser beams emitted by the three laser rangefinders are parallel to the normal of the laser radar to be measured, and the positions of the three laser rangefinders form a triangle;

[0016] The host computer adjusts the spatial positions of the three laser rangefinders through the coarse adjustment system and the first fine adjustment system so that the triangle is perpendicular to the ground.

[0017] According to one embodiment of the present invention, the triangle is an isosceles triangle, and the emission center of the laser radar to be tested is located at the center of the isosceles triangle.

[0018] According to one embodiment of the present invention, the coarse adjustment system is used to preliminarily adjust the spatial positions of the three laser rangefinders so that the lasers emitted by the three laser rangefinders fall on the calibration plate; the host computer finely adjusts the spatial positions of the three laser rangefinders and the posture of the calibration plate through the first fine adjustment system and the second fine adjustment system respectively so that the distances between the three laser rangefinders and the calibration plate are equal.

[0019] According to one embodiment of the present invention, the fine adjustment of the spatial positions of the three laser rangefinders by the first fine adjustment system is based on the time-of-flight method, and the calculation formula of the time-of-flight method is:

[0020]

[0021] Where L is the target distance, n is the refractive index of air, c is the speed of light, and t is the delay of the echo relative to the transmitted beam.

[0022] According to one embodiment of the present invention, the second fine adjustment system includes a second movable roller, a second retractable support leg, an RZ axis adjustment mechanism, and an RY axis adjustment mechanism. The second movable roller and the second retractable support leg are provided at the bottom of the RZ axis adjustment mechanism. The target plate trolley is transferred to the test position by the second movable roller. The height of the second retractable support leg is adjustable. The second retractable support leg is lowered to fix the target plate trolley in the test position.

[0023] The support frame is fixed to the RZ-axis adjustment mechanism through the RY-axis adjustment mechanism. The RZ-axis adjustment mechanism is used to adjust the horizontal rotation angle of the calibration plate, and the RY-axis adjustment mechanism is used to adjust the pitch angles of the calibration plate and the reflector.

[0024] The present invention also provides a laser radar test method, which is applicable to the aforementioned laser radar test system, and the test method comprises the following steps:

[0025] Move the laser radar calibration trolley to a set position and fix it;

[0026] Move the target plate trolley to a set position and fix it, fix the reflector plate to the support frame, and fix the calibration plate to the support frame and cover the reflector plate;

[0027] Observe through the telescope and adjust the laser positioning system via the coarse adjustment system so that the crosshairs of the telescope are preliminarily aligned with the mark on the calibration plate; level the target plate carriage;

[0028] Turning on the total station and leveling the main support using the leveling mechanism;

[0029] According to the distances between the laser beams emitted by the three laser rangefinders and the calibration plate, the host computer adjusts the position of the laser positioning system through the first fine adjustment system and adjusts the position of the calibration plate through the second fine adjustment system so that the crosshairs of the telescope are aligned with the marks on the calibration plate;

[0030] Remove the calibration plate.

[0031] According to one embodiment of the present invention, the laser beams emitted by the three laser rangefinders are parallel to the normal of the laser radar to be measured, and the positions of the three laser rangefinders form a triangle; when the total station is in a leveling state, the triangle is perpendicular to the ground;

[0032] The process of aligning the crosshairs of the telescope with the markings on the calibration plate includes:

[0033] The distances between the three laser rangefinders and the calibration plate are measured, and the host computer calculates the angular deviation between the calibration plate and the triangle;

[0034] The host computer adjusts the posture of the calibration plate through the second fine adjustment system so that the triangle is parallel to the calibration plate.

[0035] The present invention provides a laser radar testing method and a laser radar testing system, which can realize long-distance, high-precision performance testing of the laser radar through a two-level adjustment of "coarse adjustment + fine adjustment" combined with total station calibration, and ensure the repeatability of the test results.

[0036] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are included to provide further explanation of the present invention and are incorporated into and constitute a part of this application. The accompanying drawings illustrate embodiments of the present invention and together with the description serve to explain the principle of the present invention.

[0038] In the attached figure:

[0039] Figure 1 A schematic structural diagram of a laser radar testing system according to an embodiment of the present invention is shown.

[0040] Figure 2 A schematic structural diagram of a laser radar calibration vehicle according to an embodiment of the present invention is shown.

[0041] Figure 3 A schematic structural diagram of a target board trolley according to an embodiment of the present invention is shown.

[0042] Figure 4 A schematic diagram of distance measurement using a laser rangefinder and a calibration plate during posture adjustment according to an embodiment of the present invention is shown.

[0043] Figure 5 A flowchart of a lidar testing method according to an embodiment of the present invention is shown.

[0044] The above drawings include the following reference numerals:

[0045] LiDAR Test System 100

[0046] LiDAR Calibration Car 101

[0047] Target board car 102

[0048] Coarse adjustment system 103

[0049] First fine adjustment system 104

[0050] Test System 105

[0051] Laser positioning system 106

[0052] Lifting mechanism 107

[0053] Support assembly 108

[0054] Leveling mechanism 109

[0055] Fine adjustment mechanism 110

[0056] Total Station 111

[0057] Test turntable 112

[0058] Telescope 113

[0059] Laser rangefinder 114

[0060] Second fine adjustment system 115

[0061] Support frame 116

[0062] Calibration plate 117

[0063] First moving roller 118

[0064] First retractable support leg 119

[0065] Z-axis fine adjustment mechanism 120

[0066] X / Y axis fine adjustment mechanism 121

[0067] RZ axis fine adjustment mechanism 122

[0068] Second moving roller 123

[0069] The second retractable support leg 124

[0070] RZ axis adjustment mechanism 125

[0071] RY axis adjustment mechanism 126

[0072] Radar calibration system 127

[0073] Electric control box 128

[0074] Main bracket 129

[0075] LiDAR 200 to be tested DETAILED DESCRIPTION

[0076] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0077] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0078] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0079] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. Technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0080] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0081] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0082] Figure 1 A schematic structural diagram of a laser radar testing system according to an embodiment of the present invention is shown. Figure 2 A schematic structural diagram of a laser radar calibration vehicle according to an embodiment of the present invention is shown. Figure 3 A schematic diagram of a target board trolley according to an embodiment of the present invention is shown. As shown in the figure, a laser radar test system 100 mainly includes a laser radar calibration trolley 101, a target board trolley 102, and a radar calibration system 127, which work together to achieve high-precision alignment and testing.

[0083] The LiDAR calibration cart 101 includes a coarse adjustment system 103, a first fine adjustment system 104, a test system 105, and a laser positioning system 106. The coarse adjustment system 103 includes a lifting mechanism 107 and a support assembly 108 at its base, enabling initial positioning and height adjustment. The first fine adjustment system 104 includes a leveling mechanism 109 and a fine adjustment mechanism 110. The fine adjustment mechanism 110 is mounted on the lifting mechanism 107 via the leveling mechanism 109. The leveling mechanism 109 includes three leveling handwheels. Rotating the handwheels allows the fine adjustment system mounted on it, along with the test system 105 and the laser positioning system 106 on the main support 129, to be aligned parallel to the ground. The first fine adjustment system 104 ensures equipment levelness and provides fine position adjustment. The test system 105 includes a total station 111 and a test turntable 112. The total station 111 is secured to the main support 129 via a chuck. The test turntable 112 is suitable for mounting the LiDAR 200 under test. The laser positioning system 106 includes a telescope 113 and three laser rangefinders 114. It is mounted on a total station 111. A lifting mechanism 107 adjusts the overall height within a range of 0 to 100 mm. The fine-tuning mechanism 110 has an adjustment accuracy of ±0.1 mm / ±0.1°. The total station 111 boasts higher accuracy than the laser radar 200 under test. A test turntable 112 is used for performance testing and true value calibration.

[0084] The target plate trolley 102 serves as a reflective target carrier. The target plate trolley 102 includes a second fine-tuning system 115, a support frame 116, a reflector, and a calibration plate 117. The support frame 116 is arranged on the second fine-tuning system 115. The reflector is a standard diffuse reflector fixed on the support frame 116. The second fine-tuning system 115 is used to achieve precise adjustment of the normal direction of the reflector. The calibration plate 117 is suitable for being fixed to the support frame 116 to cover the reflector. The calibration plate 117 is used for temporary mounting to assist the alignment process (marking the laser landing point). The two realize the rapid loading and unloading of the calibration plate 117 through a quick connection structure.

[0085] The radar calibration system 127 implements global control and data processing through the host computer. Based on the three-dimensional distance data fed back by the laser rangefinder 114, the host computer coordinates and controls the first fine-tuning system 104 of the laser radar calibration trolley 101 and the second fine-tuning system 115 of the target board trolley 102, dynamically adjusts the relative position of the reflector and the laser radar, and ultimately achieves high-precision alignment between the normal of the reflector and the emission direction of the laser radar 200 to be tested. The radar calibration system 127 can be set on the laser radar calibration trolley 101. It has a wifi communication module that can realize communication between the laser radar calibration trolley 101 and the target board trolley 102, complete the sending of control instructions and receive the current trolley data and status information. The host computer realizes user interface functions such as parameter setting, status monitoring, switching between manual / automatic control, etc. during the fine-tuning and testing process, and realizes scheduling and coordinated actions between the two trolleys through the control logic module.

[0086] In some examples, the support assembly 108 includes an integrated first movable roller 118 and a first retractable support leg 119. The laser radar calibration trolley 101 is quickly transferred to the test position by the first movable roller 118. The height of the first retractable support leg 119 is adjustable, and the first retractable support leg 119 is lowered to fix the laser radar calibration trolley 101 to the bottom surface of the test position, forming a rigid support base. The lifting mechanism 107 adjusts the vertical height based on the base, and by controlling the height position of the laser positioning system 106, ensures that it achieves height matching with the reflector on the target board trolley 102, providing basic spatial positioning guarantee for subsequent precise alignment.

[0087] In some examples, the fine-tuning mechanism 110 utilizes a hierarchical, multi-dimensional adjustment architecture, with components stacked sequentially according to their functional logic: the Z-axis fine-tuning mechanism 120, placed atop the lifting mechanism 107, is responsible for fine-tuning the vertical height; the X / Y-axis fine-tuning mechanism 121 above it is responsible for two-dimensional translation adjustment in the horizontal plane; and the topmost RZ-axis fine-tuning mechanism 122 achieves fine adjustment of the horizontal rotation angle. This bottom-up layout allows Z-axis adjustment to provide a stable reference for X / Y-axis translation, while X / Y-axis position calibration lays the foundation for RZ-axis rotation positioning. These three components work together to achieve high-precision correction of the spatial position of the laser positioning system 106 by precisely controlling its vertical height, horizontal position, and horizontal rotation angle, providing fine adjustment capability for the normal alignment of the reflector and the laser radar 200 under test.

[0088] In some examples, the laser beams emitted by the three laser rangefinders 114 are parallel to the normal of the laser radar 200 under test and the axis of the telescope 113, forming a triangular arrangement. The host computer coordinates and controls the first fine-tuning system 104 to adjust the spatial positions of the three laser rangefinders 114 so that the plane of the triangle is perpendicular to the ground. This design ensures a unified reference for ranging, detection, and observation by ensuring the consistency of the directions of the multiple beams. The perpendicularity of the triangle to the ground provides a regular geometric reference for analyzing the reflector's posture based on the three-point distance difference, ensuring the accuracy of alignment adjustments.

[0089] In some examples, the triangle is an isosceles triangle, and the emission center of the laser radar 200 to be tested is located at the center of the isosceles triangle. Specifically, the spatial arrangement of the three laser rangefinders 114 forms an isosceles triangle structure, and the emission center of the laser radar 200 to be tested coincides with the center of the isosceles triangle. This symmetrical layout creates a spatially centrally symmetrical relationship between the measurement reference of the laser rangefinder 114 and the radar emission reference, ensuring the balance of the three ranging points in detecting the attitude of the reflector. The center-coincidence design eliminates the spatial offset error between the ranging reference and the detection reference, providing symmetrical geometric conditions for subsequent attitude calculation based on the three-point distance difference, further improving the accuracy and stability of the alignment adjustment.

[0090] In some examples, the host computer achieves precise coordination between the laser rangefinder 114 and the calibration plate 117. Through observation by the telescope 113, the coarse adjustment system 103 makes preliminary adjustments to the spatial positions of the three laser rangefinders 114 to ensure that the lasers emitted by them can all fall on the calibration plate 117, completing basic alignment. Subsequently, the host computer collaboratively controls the first fine adjustment system 104 and the second fine adjustment system 115 to respectively make fine corrections to the spatial positions of the laser rangefinders 114 and accurately adjust the posture of the calibration plate 117, ultimately making the distances from the three laser rangefinders 114 to the calibration plate 117 tend to be equal. This dual-system collaborative adjustment method not only quickly establishes measurement associations through coarse adjustment, but also eliminates spatial deviations with the help of two-way fine adjustment in the fine adjustment stage. Through the judgment standard of equal distance, it intuitively reflects the perpendicular relationship between the laser beam and the calibration plate 117, providing a quantitative basis for the normal alignment of the reflector and the lidar.

[0091] Figure 4A schematic diagram illustrates the distance measurement of a laser rangefinder and a calibration plate during the posture adjustment process according to one embodiment of the present invention. As shown, during the fine-tuning process, three laser rangefinders 114 arranged in an isosceles triangle (ABC) emit parallel laser beams toward a calibration plate 117. The projections form three laser marks (A', B', C'), and the corresponding distance data (dA, dB, and dC) are transmitted in real time to a host computer. Because triangle ABC is perpendicular to the ground, and the emission center (D) of the laser radar 200 under test is located at the center of the triangle, this geometric arrangement makes the three distance values ​​the key basis for reflecting the posture relationship between the reflector and the radar. When dA, dB, and dC are equal, it indicates that the normal direction of the laser radar 200 under test remains perpendicular to the reflector. If the distances are unequal, the host computer can control the first fine-tuning mechanism 110 of the laser radar calibration cart 101 in conjunction with the second fine-tuning mechanism of the target plate cart 102 to automatically adjust the distances. By correcting for spatial position deviations, high-precision alignment of the reflector and the normal of the laser radar 200 under test is ultimately achieved. This adjustment logic based on three-point distance consistency transforms abstract pose alignment into quantifiable distance parameter control, significantly improving the accuracy and automation level of the alignment process.

[0092] In some examples, the fine adjustment of the spatial positions of the three laser rangefinders 114 by the first fine adjustment system 104 is based on the time-of-flight (ToF) method. The calculation formula of the time-of-flight method is:

[0093]

[0094] Where L is the target distance; n is the refractive index of air, set to 1.000278; c is the speed of light, set to 299,792,458 m / s to ensure measurement accuracy; and t is the delay of the echo relative to the transmitted beam. This distance measurement method based on the propagation time of light provides a highly accurate distance measurement basis for the laser rangefinder 114 by directly linking physical quantities to the quantitative relationship between distance. The first fine-tuning system 104 uses this measurement result as feedback to accurately correct the spatial position of the laser rangefinder 114, ensuring the accuracy of subsequent alignment adjustments from the source of the data.

[0095] In some instances, the second fine-tuning system 115 integrates movement, fixation, and angle adjustment functions. The second fine-tuning system 115 includes a second movable roller 123, a second retractable support leg 124, an RZ-axis adjustment mechanism 125, and an RY-axis adjustment mechanism 126. Among them, the RZ-axis adjustment mechanism 125 is equipped with a second movable roller 123 and a second retractable support leg 124. After the target plate trolley 102 is quickly transferred to the test position by the second movable roller 123, the second retractable support leg 124 with adjustable height is lowered to achieve stable fixation. The support frame 116 is connected to the RZ-axis adjustment mechanism 125 via the RY-axis adjustment mechanism 126, wherein the RZ-axis adjustment mechanism 125 is responsible for adjusting the horizontal rotation angle of the calibration plate 117, and the RY-axis adjustment mechanism 126 controls the pitch angle of the calibration plate 117 and the reflector. This design ensures the deployment flexibility of the target board cart 102 through the coherent logic of "moving-fixing-dual-axis angle adjustment". It also provides attitude adjustment capability for the normal alignment of the reflector and the lidar through precise angle correction in the horizontal and pitch directions. It forms a synergistic relationship with the adjustment function of the lidar calibration cart 101 to jointly improve the alignment accuracy.

[0096] Figure 5 The flowchart of a laser radar test method according to an embodiment of the present invention is shown. As shown in the figure, the present invention also provides a laser radar test method applicable to the aforementioned laser radar test system 100. The test method includes the following steps:

[0097] S1, move the laser radar calibration vehicle 101 to the set position and fix it;

[0098] S2: Move the target plate trolley 102 to the set position and fix it. The laser radar calibration trolley 101 and the target plate trolley 102 are usually set at both ends of the test site. Fix the reflector to the support frame 116, and fix (mount) the calibration plate 117 to the support frame 116 and cover the reflector.

[0099] S3, observe through the telescope 113, and adjust the laser positioning system 106 via the coarse adjustment system 103 to preliminarily align the cross cursor of the telescope 113 with the mark on the calibration plate 117. Specifically, the height of the cross cursor of the manual observation telescope 113 is located near the F' mark of the calibration plate 117, and the target plate trolley 102 is moved laterally so that the position of the cross cursor of the manual observation telescope 113 is located near the F' mark of the calibration plate 117. In this example, it is recommended that the difference between the distance range placement position and the target distance be ≤100mm; the angle deviation range is -15° to +15°. During the leveling process of the target plate trolley 102, a spirit level can be placed on the RZ axis adjustment mechanism 125, and leveling can be performed by adjusting the height of the second retractable support leg 124.

[0100] S4: Turn on the total station 111 and use the leveling mechanism 109 to level the main support 129. Based on the leveling status displayed on the total station 111, adjust the leveling mechanism 109 using the handwheel to bring the inclination angle as close to 0° as possible. At this point, the main support 129 is leveled, and the triangle formed by the three laser rangefinders 114 is perpendicular to the ground.

[0101] S5: Based on the distances between the laser beams emitted by the three laser rangefinders 114 and the calibration plate 117, the host computer controls the first fine adjustment system 104 to adjust the position of the laser positioning system 106, and adjusts the position of the calibration plate 117 through the second fine adjustment system 115, so that the crosshairs of the telescope 113 are precisely aligned with the markings on the calibration plate 117.

[0102] S6, remove the calibration plate 117 and perform testing using a reflective plate.

[0103] This lidar testing method uses the progressive operation of "fixed deployment - initial alignment - precise leveling - accurate alignment - removal of auxiliary devices", combined with the coordination of mechanical adjustment and data feedback, to gradually reduce the alignment error. It not only ensures the orderliness of the operation, but also ensures the position accuracy of the reflector and lidar through a multi-dimensional adjustment mechanism, providing a reliable foundation for subsequent tests.

[0104] In some examples, the laser beams emitted by the three laser rangefinders 114 are parallel to the normal of the laser radar 200 to be measured, and the positions of the three laser rangefinders 114 form an isosceles triangle; when the total station 111 is in a leveling state, the triangle is perpendicular to the ground. Figure 4 The process of aligning the crosshairs F of the telescope 113 with the mark F' on the calibration plate 117 includes:

[0105] The distances between the three laser rangefinders 114 and the calibration plate 117 are measured, and the upper computer calculates the angular deviation between the calibration plate 117 and the triangle. Specifically, the upper computer first triggers and starts the three laser rangefinders 114 at the same time to measure the distance. The three laser rangefinders 114 form a triangle ABC, and the projection points on the calibration plate 117 form a triangle A'B'C'. The three distances from point A to A', point B to B', and point C to C' are measured as dA1, dB1, and dC1. Based on the parallel relationship between the three distance values ​​and the three laser beams, the upper computer can calculate the angle difference between the plane where the triangle A'B'C' projected by the three laser beams on the calibration plate 117 is located and the plane where the triangle ABC formed by the three laser rangefinders 114 is located, and decompose the angle difference into the pitch angle Ry adjustment amount and the horizontal angle Rz adjustment amount (since the rotation of the reflector in the Rx direction does not affect the radar test, Rx is not considered).

[0106] The host computer adjusts the position of the calibration plate 117 through the second fine-tuning system 115. The target plate trolley 102 is equipped with an electrical control box 128, through which the host computer controls the two-dimensional rotation of the calibration plate 117. Specifically, the horizontal rotation angle of the calibration plate 117 is adjusted through the RZ-axis adjustment mechanism 125, and the pitch angle of the calibration plate 117 and the reflector plate are adjusted through the RY-axis adjustment mechanism 126. The host computer controls the target plate trolley 102 to adjust the corresponding angles of the calibration plate 117. Next, the distances between the three laser rangefinders 114 and the calibration plate 117 are remeasured as dA2, dB2, and dC2. The angular difference between plane A'B'C' and plane ABC is recalculated and adjusted. This process is repeated until the difference between dAn, dBn, and dCn is within the maximum allowable error range. In this case, the plane containing triangle A'B'C' is considered parallel to the plane containing triangle ABC, and the automatic adjustment process ends. Through manual observation, the crosshairs F of telescope 113 are aligned with mark F' on calibration plate 117. Fine adjustment is achieved when the laser points emitted by the three laser rangefinders 114, located at ABC, fall on the corresponding marks A', B', and C' on calibration plate 117. It should be noted that the normal direction of laser point E emitted by total station 111 falls on point E' on calibration plate 117. Total station 111 provides a relative true value for the positional relationship between the LiDAR calibration cart 101 and the target plate cart 102.

[0107] The laser radar test system and laser radar test method provided by the present invention can quickly and accurately carry out long-distance laser radar performance tests such as distance, angle and reflection characteristics without being restricted by indoor venues. Among them, distance performance includes ranging accuracy, maximum detection distance, etc., mainly by placing reflectors at different distances and carrying out relevant distance tests after alignment; angle testing is mainly achieved by rotating the test turntable in the horizontal or pitch direction, including angle range (FOV) and angle accuracy. As an extension, the reflector can be replaced with two long rods or other equipment to carry out angle resolution testing; reflection characteristic testing is mainly carried out by replacing reflectors with different reflectivities and coupling distance and angle parameters. Reflection characteristic analysis of different reflectivities at different distances / angles can be carried out. In order to improve test efficiency and reduce the number of calibration times, the test plan can be disassembled and rearranged. After all tests at a certain distance are completed, the next test distance is moved on until all test items are completed.

[0108] It will be apparent to those skilled in the art that various modifications and variations may be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention cover modifications and variations of the present invention that fall within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A laser radar test system, comprising: A laser radar calibration trolley includes a coarse adjustment system, a first fine adjustment system, a main support, a test system, and a laser positioning system. The coarse adjustment system includes a lifting mechanism and a support assembly arranged at the bottom of the lifting mechanism. The first fine adjustment system includes a leveling mechanism and a fine adjustment mechanism. The fine adjustment mechanism is arranged on the lifting mechanism via the leveling mechanism. The main support is fixed to the first fine adjustment system. The test system includes a total station and a test turntable arranged on the main support. The test turntable is suitable for installing a laser radar to be tested. The leveling mechanism levels the main support via the total station. The laser positioning system includes a telescope and three laser rangefinders. The laser positioning system is arranged on the main support. A target plate trolley comprises a second fine adjustment system, a support frame, a reflective plate and a calibration plate, wherein the support frame is arranged on the second fine adjustment system, the reflective plate is fixed on the support frame, and the calibration plate is suitable for being fixed to the support frame to cover the reflective plate; The radar calibration system includes a host computer, which is used to control the laser radar calibration cart and the target board cart. The host computer fine-tunes the position of the laser positioning system through the first fine-tuning system, and adjusts the position of the calibration board through the second fine-tuning system to align the normal of the reflector with the emission direction of the laser radar to be measured.

2. The laser radar test system according to claim 1, wherein: The support assembly includes a first movable roller and a first retractable support leg, the laser radar calibration trolley is moved to the test position by the first movable roller, the height of the first retractable support leg is adjustable, and the first retractable support leg is lowered to fix the laser radar calibration trolley in the test position; The lifting mechanism is used to adjust the height of the laser positioning system so that the heights of the laser positioning system and the reflective plate are aligned.

3. The laser radar test system according to claim 1, wherein: The fine adjustment mechanism includes a Z-axis fine adjustment mechanism, an X / Y-axis fine adjustment mechanism and an RZ-axis fine adjustment mechanism, wherein the Z-axis fine adjustment mechanism is arranged on the top of the lifting mechanism, the X / Y-axis fine adjustment mechanism is arranged on the top of the Z-axis fine adjustment mechanism, and the RZ-axis fine adjustment mechanism is arranged on the top of the X / Y-axis fine adjustment mechanism; The Z-axis fine-tuning mechanism is used to fine-tune the height position of the laser positioning system in the vertical direction, the X / Y-axis fine-tuning mechanism is used to fine-tune the position of the X-axis and Y-axis of the laser positioning system in the horizontal direction, and the RZ-axis fine-tuning mechanism is used to adjust the horizontal rotation angle of the laser positioning system.

4. The laser radar test system according to claim 1, wherein: The laser beams emitted by the three laser rangefinders are parallel to the normal of the laser radar to be measured, and the positions of the three laser rangefinders form a triangle; The host computer adjusts the spatial positions of the three laser rangefinders through the coarse adjustment system and the first fine adjustment system so that the triangle is perpendicular to the ground.

5. The laser radar test system according to claim 4, wherein: The triangle is an isosceles triangle, and the emission center of the laser radar to be tested is located at the center of the isosceles triangle.

6. The laser radar test system according to claim 4, wherein: The coarse adjustment system is used to preliminarily adjust the spatial positions of the three laser rangefinders so that the lasers emitted by the three laser rangefinders fall on the calibration plate; the host computer finely adjusts the spatial positions of the three laser rangefinders and the posture of the calibration plate through the first fine adjustment system and the second fine adjustment system respectively so that the distances between the three laser rangefinders and the calibration plate are equal.

7. The laser radar test system according to claim 4, wherein: The fine adjustment of the spatial positions of the three laser rangefinders by the first fine adjustment system is based on the time-of-flight method, and the calculation formula of the time-of-flight method is: Where L is the target distance, n is the refractive index of air, c is the speed of light, and t is the delay of the echo relative to the transmitted beam.

8. The laser radar test system according to claim 1, wherein: The second fine adjustment system includes a second movable roller, a second retractable support leg, an RZ axis adjustment mechanism, and an RY axis adjustment mechanism. The second movable roller and the second retractable support leg are provided at the bottom of the RZ axis adjustment mechanism. The target plate trolley is transferred to the test position by the second movable roller. The height of the second retractable support leg is adjustable. The second retractable support leg is lowered to fix the target plate trolley in the test position. The support frame is fixed to the RZ-axis adjustment mechanism through the RY-axis adjustment mechanism. The RZ-axis adjustment mechanism is used to adjust the horizontal rotation angle of the calibration plate, and the RY-axis adjustment mechanism is used to adjust the pitch angles of the calibration plate and the reflector.

9. A laser radar testing method, applicable to the laser radar testing system according to any one of claims 1 to 8, the testing method comprising the steps of: Move the laser radar calibration trolley to a set position and fix it; Move the target plate trolley to a set position and fix it, fix the reflector plate to the support frame, and fix the calibration plate to the support frame and cover the reflector plate; Observe through the telescope and adjust the laser positioning system via the coarse adjustment system so that the crosshairs of the telescope are preliminarily aligned with the mark on the calibration plate; level the target plate carriage; Turning on the total station and leveling the main support using the leveling mechanism; According to the distances between the laser beams emitted by the three laser rangefinders and the calibration plate, the host computer adjusts the position of the laser positioning system through the first fine adjustment system and adjusts the position of the calibration plate through the second fine adjustment system so that the crosshairs of the telescope are aligned with the marks on the calibration plate; Remove the calibration plate.

10. The laser radar testing method according to claim 9, wherein: The laser beams emitted by the three laser rangefinders are parallel to the normal of the laser radar to be measured, and the positions of the three laser rangefinders form a triangle; when the total station is in a leveling state, the triangle is perpendicular to the ground; The process of aligning the crosshairs of the telescope with the markings on the calibration plate includes: The distances between the three laser rangefinders and the calibration plate are measured, and the host computer calculates the angular deviation between the calibration plate and the triangle; The host computer adjusts the posture of the calibration plate through the second fine adjustment system so that the triangle is parallel to the calibration plate.

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