A multi-line lidar system for acquiring large-scale point cloud data

Abstract

The present invention discloses a multi-line laser radar system for acquiring large-scale point cloud data. By installing a multi-line laser scanner on a shell that can rotate in the vertical direction, the multi-line laser scanner follows the rotation of the shell in the vertical direction, greatly expanding the number of longitudinal lines. Compared with a single-line laser radar, the rotation efficiency is doubled, and the synthesis speed of 3D point clouds can be doubled, realizing the synthesis of large-scale, high-density 3D point cloud data, thereby solving the problem that existing laser radars consume a lot of time to synthesize and acquire 3D point cloud data of very large scene objects.

Description

Technical Field

[0001] The present invention relates to the field of smart factory technology, and in particular to a multi-line laser radar system for acquiring large-scale point cloud data. Background Art

[0002] LiDAR emits a laser beam at a target and then compares the received signal with the transmitted signal to obtain relevant information about the target, such as distance, speed, height, and shape. Currently, robots, drones, and unmanned vehicles are equipped with LiDAR to obtain external information. Currently, in various smart factories, such as automated cement bag loading sites, LiDAR is required to perform a three-dimensional scan of vehicles parked at predetermined locations to determine the specific location of the loading compartment, the shape of the available loading space, and even to obtain real-time data on the stack shape as the loader places the bags. However, in the current field of 3D point cloud applications, the mainstream hardware model is a line laser plus camera or structured light plus camera. This hardware model generates a maximum recognition range of less than 2 meters, primarily within a range of 30 cm. Although ToF radar can generate point cloud data covering tens or even hundreds of meters, ToF radar has primarily developed in the direction of multi-line scanning, from 1 to 16, then 32, and finally 128 lines, with a limited number of vertical lines. The range of a single image is generally small. However, a single-line radar is ten or even dozens of times slower than a multi-line radar in synthesizing a point cloud of the same density. Summary of the Invention

[0003] In response to the deficiencies in the prior art, the present invention provides a multi-line laser radar system for acquiring large-scale point cloud data, comprising a multi-line laser scanner, a radar bracket, and a control device; wherein the radar bracket comprises a first shell, a second shell for mounting the multi-line laser scanner, and a servo motor mounted in the first shell; the first shell is provided with a placement space for accommodating the second shell, the second shell is mounted in the placement space via a shell shaft and can rotate relative to the first shell under the drive of the servo motor; the second shell is provided with a light source window for the light beam of the multi-line laser scanner mounted therein to pass through The light source window can enter and exit the placement space following the rotation of the second shell; the control device is electrically connected to the multi-line laser scanner and the servo motor, respectively, and is configured to obtain the distance value, horizontal angle and serial number of each single-point laser from the scanner, and convert each single-point laser data obtained from the scanner from polar coordinates into data in the bracket coordinate system according to the rotation angle and speed of the shell shaft driven by the servo motor, and synthesize the point cloud data of the laser scanner in the bracket coordinate system. The bracket coordinate system takes the axis center of the shell shaft as the origin, and the axis of the shell shaft is perpendicular to the X-axis of the bracket coordinate system and the X-axis of the radar coordinate system respectively.

[0004] Preferably, the control device is further configured to obtain the angle value Vn of the vertical angle of the bracket of the single-point laser data of the nth point, where v n =(p / ((p / 360°) / s*m-1)*n), where p is the operating angle of the shell shaft, s is the operating speed of the shell shaft, and m is the number of single-point lasers emitted by the multi-line laser scanner per second.

[0005] Preferably, the control device is further configured to convert each single point laser data obtained from the scanner from the radar polar coordinate system x'y'z'o' into data under the bracket coordinate system XYZO (X n Y n Z n ),in

[0006]

[0007] Y n =d n *cos t n *sin a n ;

[0008]

[0009] where X n is the x value of the single point laser at point n in the bracket coordinate system, and Y n is the y value of the single point laser at point n in the bracket coordinate system, Z n is the z value of the single point laser at point n in the bracket coordinate system, d n is the distance value of the single-point laser data at point n, t n is the vertical angle value of the single-point laser data at point n, a n is the horizontal angle value of the single-point laser data at point n, v n is the vertical angle value of the single-point laser data of the nth point in the bracket, n is the variable value of the nth point, A is the Y component of the zero point of the radar polar coordinate system in the bracket coordinate system, and B is the X component of the zero point of the radar polar coordinate system in the bracket coordinate system.

[0010] Preferably, the control device is further configured to convert each single point laser data obtained from the scanner from polar coordinates into data in the bracket coordinate system according to the rotation angle and speed of the housing shaft driven by the servo motor, and synthesize the point cloud data (X n Y n Z n ):

[0011]

[0012] Yn =d n *cos t n *sin a n ;

[0013]

[0014] where X n is the x value of the single point laser at point n in the bracket coordinate system, and Y n is the y value of the single point laser at point n in the bracket coordinate system, Z n is the z value of the single point laser at point n in the bracket coordinate system, d n is the distance value of the single-point laser data at point n, t n is the vertical angle value of the single-point laser data at point n, a n is the horizontal angle value of the single-point laser data at point n, v n is the vertical angle value of the single-point laser data of the nth point in the bracket, n is the variable value of the nth point, A is the Y component of the zero point of the radar polar coordinate system in the bracket coordinate system, B is the X component of the zero point of the radar polar coordinate system in the bracket coordinate system, p is the operating angle of the shell shaft, s is the operating speed of the shell shaft, and m is the number of single-point lasers emitted by the multi-line laser scanner per second.

[0015] Preferably, the radar bracket also includes a transmission structure connecting the servo motor and the shell rotating shaft, the first shell includes an upper shell structure with a servo motor installed inside and side shell structures fixed on both sides of the upper shell structure, the upper parts of the two side shell structures are respectively connected to the two sides of the upper shell structure, and the inner sides of the lower parts of the two side shell structures and the lower side of the upper shell structure form an unclosed placement space, wherein a transmission structure with two ends respectively connected to the servo motor and the shell rotating shaft is installed in one side shell structure; the transmission structure includes a driving wheel, a driven wheel and a synchronous belt connecting the driving wheel and the driven wheel installed in one side shell structure, the driving wheel is connected to the servo motor drive shaft, and the driven wheel is connected to a shell rotating shaft.

[0016] Preferably, the second shell includes a main shell plate, and two side plates perpendicular to the main shell plate and respectively connected to the left and right ends of the main shell plate, the two side plates are respectively connected to the corresponding side shell structures through the shell rotating shaft, the main shell plate includes a first inclined plate, a front plate, a bottom plate, a rear plate and a second inclined plate connected in sequence, the main shell plate and the two side plates surround to form an equipment chamber for installing the laser radar equipment, the rear end of the first inclined plate is connected to the front end of the front plate and is bent toward the second inclined plate, and the front end of the second inclined plate is connected to the rear end of the front plate and is bent toward the first inclined plate.

[0017] Preferably, the two side plates are respectively provided with a first groove and a second groove inward at one end away from the bottom plate, the two sides of the notch of the first groove are respectively connected to the first inclined plate and the second inclined plate, and the two sides of the notch of the second groove are also respectively connected to the first inclined plate and the second inclined plate, and the first groove, the second groove, the front end of the first inclined plate and the rear end of the second inclined plate surround to form a light source window for the light beam of the laser radar equipment to pass through.

[0018] Preferably, the first inclined plate includes a first inclined portion and a first flat portion connected front and back, the rear end of the first flat portion is connected to the front end of the front plate and is bent toward the direction close to the second inclined plate, and the first flat portion is arranged parallel to the bottom of the upper shell structure; the second inclined plate includes a second inclined portion and a second flat portion connected front and back, the front end of the second inclined portion is connected to the rear end of the front plate and is bent toward the direction close to the first inclined plate, and the second flat portion is arranged parallel to the bottom of the upper shell structure; the first groove, the second groove, the front end of the first flat portion and the rear end of the second flat portion surround to form a light source window for the light beam of the laser radar equipment to pass through.

[0019] Preferably, the second shell also includes a mounting base for installing the laser radar equipment, and the mounting base includes a base and side frames installed on both sides of the base, and shell rotating shafts are respectively installed on both sides of the two side members, and mounting channels for the corresponding shell rotating shafts to pass through are respectively provided on the two side plates, and the side plates are connected to the side frames through fasteners; the first groove is inclined toward the direction close to the second inclined plate, and the shape and arrangement direction of the second groove are consistent with the first groove, the length of the first inclined plate is greater than that of the second inclined plate, and the base is fixed to the side plate by the side frame with respect to the bottom plate.

[0020] The multi-line laser radar system for acquiring large-scale point cloud data disclosed in the present invention installs a multi-line laser scanner on a shell that can rotate in the vertical direction, so that the multi-line laser scanner follows the rotation of the shell in the vertical direction, thereby greatly expanding the number of longitudinal lines. Compared with a single-line laser radar, the rotation efficiency is doubled, and the synthesis speed of 3D point clouds can be doubled, realizing the synthesis of large-scale, high-density 3D point cloud data, thereby solving the problem that existing laser radars require a lot of time to synthesize and acquire 3D point cloud data of very large scene objects. At the same time, the laser radar installed on the second shell can enter the first shell serving as the base by rotating in a non-working state, so that the laser radar can work normally in various harsh external environments with a lot of dust and large light changes.

[0021] Additional aspects and detailed advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0023] Attachment Figure 1 A schematic diagram of the connection of a control device of a multi-line laser radar system disclosed in one embodiment.

[0024] Attachment Figure 2 The figure is a schematic structural diagram of a radar support in working state disclosed in one embodiment.

[0025] Attachment Figure 3 The figure is a schematic structural diagram of a radar support in a non-working state disclosed in one embodiment.

[0026] Attachment Figure 4 A schematic diagram of a laser radar polar coordinate system and a bracket coordinate system disclosed in one embodiment.

[0027] Attachment Figure 5 Schematic diagram of the exploded structure of a radar bracket disclosed in one embodiment

[0028] Attachment Figure 6 A schematic diagram of a transmission structure disclosed in an embodiment.

[0029] Attachment Figure 7 This is a schematic diagram of the exploded structure of the second shell disclosed in one embodiment.

[0030] Attachment Figure 8 This is a schematic structural diagram of a main shell plate disclosed in an embodiment.

[0031] Attachment Figure 9 The figure is a schematic structural diagram of a mounting base disclosed in one embodiment. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0035] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] In the present invention, unless otherwise expressly specified or limited, "above," "above," and "above" a first feature of a second feature include the first feature being directly above or obliquely above the second feature, or simply indicate that the first feature is higher in level than the second feature. "below," "below," and "below" a first feature of a second feature include the first feature being directly below or obliquely below the second feature, or simply indicate that the first feature is lower in level than the second feature.

[0037] As attached Figure 1As shown, this embodiment discloses a multi-line laser radar system for acquiring large-scale point cloud data, including a multi-line laser scanner 3, a radar bracket 1, and a control device 2. The radar bracket 1 includes a first housing 11, a second housing 12 for mounting the multi-line laser scanner 3, and a servo motor 141 mounted within the first housing 11. The first housing 11 defines a housing space 111 for accommodating the second housing 12. The second housing 12 is mounted within the housing space 111 via a housing shaft 121 and is rotatable relative to the first housing 11 by the servo motor. The second housing 12 defines a light source window 122 for transmitting the light beam from the internally mounted multi-line laser scanner. The light source window 112 can move in and out of the housing space 111 as the second housing 12 rotates. The multi-line laser radar system also includes a control device 2, which is electrically connected to the multi-line laser scanner 3 and the servo motor 141, respectively, and is configured to obtain the distance value, horizontal angle and serial number of each single-point laser from the scanner, and convert each single-point laser data obtained from the scanner from polar coordinates into data in the bracket coordinate system according to the rotation angle and speed of the shell shaft driven by the servo motor, and synthesize the point cloud data of the laser scanner in the bracket coordinate system. The bracket coordinate system takes the axis center of the shell shaft as the origin, and the axis of the shell shaft is perpendicular to the X-axis of the bracket coordinate system and the X-axis of the radar coordinate system.

[0038] When the multi-line laser scanner of the laser radar system is in working state, the servo motor 141 rotates the second housing 12 on which the multi-line laser scanner is installed to Figure 2 , the laser radar can send laser light through the light source window to scan the object below. As the multi-line laser scanner scans, the servo motor can slowly drive the second shell to rotate, thereby achieving a wide range of three-dimensional point cloud data acquisition. When the multi-line laser scanner is in the non-working state, the servo motor 141 rotates the second shell 12 on which the multi-line laser scanner is installed to Figure 3 , the light source window on the second housing rotates upward into the mounting space. This minimizes the large amount of dust from cement packaging trucks entering the second housing during non-essential working hours and affecting the laser scanner's scanning operation. This enhances the mounting bracket's protection against internal shadows and reduces the impact of harsh working environments on internal shadow testing accuracy and equipment life. The multi-line laser radar system for acquiring large-scale point cloud data in this embodiment greatly expands the number of longitudinal lines by rotating the multi-line radar in the vertical direction, exponentially improving rotation efficiency.

[0039] LiDAR data is output in polar coordinates, emitting only one laser line at a time. This embodiment utilizes a 16-line laser scanner, which transmits in a specific sequence at 3.125µs intervals. It also rotates 360° at a set frequency, such as 5Hz, 10Hz, or 20Hz. This means it simultaneously transmits vertically and horizontally while simultaneously polling a single point. In this embodiment, the initial data from the multi-line laser scanner is expressed in polar coordinates, assuming the data line interface is at a 0° horizontal angle and the radar rotates clockwise. To facilitate subsequent point cloud synthesis, the LiDAR polar coordinates must be converted to a rectangular coordinate system. Specifically, to synthesize 3D point cloud data, the LiDAR's mounting method and dimensions on the rotating bracket must take into account the radar's coordinate system orientation, and the rotation direction must be orthogonal to the LiDAR coordinate system. Therefore, the coordinate system origin can be defined as the radar's mechanical center, with the positive X-axis direction being opposite the tail line exiting, the positive Y-axis direction being 90° counterclockwise from the X-axis, and the positive Z-axis direction being perpendicular to the XY plane and pointing upward.

[0040] In this embodiment, the control device first analyzes the connected multi-line laser scanner control device. The data output by the radar is in polar coordinate format, and only one line of laser is emitted at a time. The radar of this embodiment has 16 laser lines in the vertical direction, and the 16 laser lines are polled and emitted every 3.125us in a specific order. At the same time, they are also rotating 360° according to a set frequency such as 5HZ, 10HZ or 20HZ. The vertical direction polling single point is simultaneously rotated horizontally. Taking the 16-line laser scanner of this embodiment as an example, the data parameters of the laser scanner's single-point laser vertical direction polling 16 times are obtained. The specific sequence of the single-point laser vertical direction polling 16 times is shown in the following table, where T0 is the starting time and T is the polling interval:

[0041] Channel number vertical angle Time (T = 3.125us) Channel 0 -15° <![CDATA[T0]]> Channel 1 1° <![CDATA[T0+(1*T)]]> Channel 2 -13° <![CDATA[T0+(2*T)]]> Channel 3 3° <![CDATA[T0+(3*T)]]> Channel 4 -11° <![CDATA[T0+(4*T)]]> Channel 5 5° <![CDATA[T0+(5*T)]]> Channel 6 -9° <![CDATA[T0+(6*T)]]> Channel 7 7° <![CDATA[T0+(7*T)]]> Channel 8 -7° <![CDATA[T0+(8*T)]]> Channel 9 9° <![CDATA[T0+(9*T)]]> Channel 10 -5° <![CDATA[T0+(10*T)]]> Channel 11 11° <![CDATA[T0+(11*T)]]> Channel 12 -3° <![CDATA[T0+(12*T)]]> Channel 13 13° <![CDATA[T0+(13*T)]]> Channel 14 -1° <![CDATA[T0+(14*T)]]> Channel 15 15° <![CDATA[T0+(15*T)]]>

[0042] The calculation formula for the horizontal component of a single-point laser, taking 10 Hz as an example: the horizontal angle difference between two adjacent points is: Angle_Azimuth = 360° * 10 Hz / (1s / 0.000003125s) = 0.01125°, Point n = (vertical angle, horizontal angle), Point 0 = (-15°, 0°), Point 1 = (1°, 0.01125°).

[0043] The control device then calculates and obtains the relationship between the scanning order and angle of a single point of the laser scanner. Taking the scanner scanning frequency of 10Hz as an example, the 0th to 31st points (vertical angle, horizontal angle) are as follows:

[0044]

[0045]

[0046] From the table above, we can see that the horizontal angle a n =n*0.01125°, vertical angle t n It is a cyclic value of {-15,1,-13,3,-11,5,-9,7,-7,9,-5,11,-3,13,-1,15}.

[0047] In order to expand the point cloud density in the vertical direction, i.e., the Z-axis, the scanner is fixedly mounted on a rotating housing, where the rotation direction must be orthogonal to the scanner coordinate system. After confirming the laser radar polar coordinate system, the coordinate system of the laser radar mounted on the rotating bracket, i.e., the second housing, is obtained. Since the rotation axis is fixed, the rotation axis of the second housing is defined as the origin of the bracket's rectangular coordinate system, which can greatly simplify the algorithm. The specific bracket coordinate system is established as shown in the attached figure. Figure 4 As shown, the X-axis of the bracket coordinate system and the X-axis of the radar are in the rotation plane of the second shell. According to the position of the starting angle specified by the laser scanner, the polar coordinate data obtained from the scanner can be converted into coordinates in the rectangular coordinate system through the following calculation formula. The distance value (Distance), horizontal angle (Azimuth) and serial number (n) of each single point laser are obtained from the scanner. The formula for converting single point laser data from polar coordinates to rectangular coordinates is as follows: The rectangular coordinate system coordinate of point n (x′ n ,y′ n ,z′ n )as follows:

[0048] x′ n =d n *cos t n *cos a n ;

[0049] y′ n =d n *cos t n *sin a n ;

[0050] z′ n =d n *sin t n ;

[0051] where x′ n is the x value of the single point laser x'y'z'o' rectangular coordinate system at point n; y' n is the y value of the single-point laser x'y'z'o' rectangular coordinate system at point n; z' n is the z value of the single-point laser x'y'z'o' rectangular coordinate system at point n; d n is the distance value of the single-point laser data at point n; t nis the vertical angle value of the single-point laser data at point n; a n is the horizontal angle value of the single-point laser data at point n; after the above formula conversion, the coordinate (x′ n ,y′ n ,z′ n ), with the zero point established at the center of the laser scanner. The laser radar's coordinate system was clearly defined, and the radar was mounted on a rotating bracket. While rotating vertically and horizontally, the data from a single laser line rotating vertically around a fixed axis was synthesized into point cloud data. By converting the radar's polar coordinate system to a rectangular coordinate system for each single point, and then converting it back to the bracket's coordinate system, 3D point cloud data was generated by polling and calculating each point.

[0052] In this embodiment, the control device is further configured to obtain the angle value Vn of the vertical angle of the bracket of the single-point laser data of the nth point, where v n =(p / ((p / 360°) / s*m-1)*n), where p is the operating angle of the shell shaft, s is the operating speed of the shell shaft, and m is the number of single-point lasers emitted by the multi-line laser scanner per second.

[0053] Specifically, in this embodiment, the laser scanner emits a single-point laser beam at intervals of 3.125 us, with 320,000 points of data in 1 second. The horizontal angle resolution of the laser scanner is 0.01125°, and the vertical angle of the laser scanner is polled according to the specified angle, theta

[16] = {-15, 1, -13, 3, -11, 5, -9, 7, -7, 9, -5, 11, -3, 13, -1, 15}; the laser scanner data is precisely matched with the motor running trajectory, and the various parameters of the servo motor are clear, the servo motor running angle angle_motor = p (unit degree), and the servo motor running speed speed_motor = s (unit circle / second). When the servo motor runs at an angle of p and a running speed of s, it takes time t = (p / 360°) / s, and the amount of single-point data of the laser scanner generated within time t is q = t*320,000. Therefore, the angle difference between each two single-point data of the laser scanner is: Δv = v n -v n-1 =p / (q-1)=(p / ((p / 360°) / s*320000-1)*n); vertical angle of the nth single point laser: v n =(p / ((p / 360°) / s*320000-1)*n).

[0054] In this embodiment, the control device is further configured to convert each single point laser data obtained from the scanner from the radar polar coordinate system x'y'z'o' into data in the bracket coordinate system XYZO (X nY n Z n ),in:

[0055]

[0056] Y n =d n *cos t n *sin a n ;

[0057]

[0058] where X n is the x value of the single point laser at point n in the bracket coordinate system, and Y n is the y value of the single point laser at point n in the bracket coordinate system, Z n is the z value of the single point laser at point n in the bracket coordinate system, d n is the distance value of the single-point laser data at point n, t n is the vertical angle value of the single-point laser data at point n, a n is the horizontal angle value of the single-point laser data at point n, v n is the vertical angle value of the single-point laser data of the nth point in the bracket, n is the variable value of the nth point, A is the Y component of the zero point of the radar polar coordinate system in the bracket coordinate system, and B is the X component of the zero point of the radar polar coordinate system in the bracket coordinate system.

[0059] In this embodiment, the vertical angle v of each single point laser is adjusted according to the rotation angle and speed of the housing shaft driven by the servo motor. n Substitute the above coordinates (X n Y n Z n ), synthesize the point cloud data of the laser scanner in the bracket coordinate system, where the point cloud data (X n Y n Z n ) are as follows:

[0060]

[0061] Y n =d n *cos t n *sin a n ;

[0062]

[0063] where X n is the x value of the single-point laser at point n in the bracket coordinate system;

[0064] Yn is the y value of the single-point laser at point n in the bracket coordinate system;

[0065] Z n is the z value of the single-point laser at point n in the bracket coordinate system;

[0066] d n is the distance value of the single-point laser data of point n;

[0067] t n is the vertical angle value of the single-point laser data at point n;

[0068] a n is the horizontal angle value of the single-point laser data at point n;

[0069] v n The vertical angle value of the single-point laser data of point n on the bracket;

[0070] n is the variable value of the nth point;

[0071] A is the Y component of the zero point of the radar polar coordinate system in the bracket coordinate system;

[0072] B is the X component of the zero point of the radar polar coordinate system in the bracket coordinate system;

[0073] p is the operating angle of the housing shaft;

[0074] s is the running speed of the housing shaft;

[0075] m is the number of single-point lasers emitted per second by the multi-line laser scanner.

[0076] The above data is calculated by iterative accumulation of n starting from 0 through the above algorithm. After the initial state is set, the point cloud data of the laser scanner in the XYZO coordinate system can be obtained.

[0077] Conventional single-line laser scanner synthesis methods use only a single line of data, and calculations are performed within a single plane based on the vertical angle of that plane. For example, at a 25 Hz scanner frequency, 25 frames of data are synthesized per second, resulting in significant vertical angle variations. This embodiment utilizes a multi-line laser scanner to generate data in a three-dimensional manner. Rotational vertical angle variables are incorporated into the transformation calculations for each point, resulting in 320,000 points of data and 320,000 frames of data synthesized per second, achieving higher-precision matching. By installing the multi-line laser scanner on a shell that can rotate in the vertical direction, the multi-line laser scanner follows the rotation of the shell in the vertical direction, which greatly expands the number of longitudinal lines. Compared with the single-line laser radar, the rotation efficiency is doubled, and the synthesis speed of 3D point cloud can be doubled, realizing the synthesis of large-scale, high-density 3D point cloud data, thereby solving the problem that the existing laser radar takes a lot of time to synthesize and obtain 3D point cloud data of ultra-large scene objects. At the same time, the laser radar installed on the second shell can enter the first shell serving as the base by rotating in the non-working state, so that the laser radar can work normally in various harsh external environments with a lot of dust and large light changes.

[0078] In this embodiment, as shown in the attached Figure 5 and 6As shown, the laser radar bracket also includes a transmission structure connecting the drive motor 141 and the housing shaft 121. The first housing 11 includes an upper housing structure 112 with the drive motor installed inside and side housing structures 113 and 114 fixed to either side of the upper housing structure 112. The upper portions of the two side housing structures are respectively connected to the two sides of the upper housing structure 112. The lower inner sides of the two side housing structures and the lower side of the upper housing structure surround an open housing space 111. One side housing structure is installed with a transmission structure with two ends connected to the drive motor and the housing shaft. The transmission structure 142 includes a driving wheel 1421 and a driven wheel 1422 installed in the side housing structure, and a synchronous belt 1423 connecting the driving and driven wheels. The driving wheel 1421 is connected to the drive shaft of the drive motor 41, and the driven wheel 1422 is connected to a housing shaft. The second housing is rotatably connected to the inner sides of the two side housing structures via the housing shafts on both sides and can rotate up and down around the housing shaft within the housing space. By installing a drive motor on the upper shell structure and a transmission structure on the side shell structure, the upper drive motor can directly drive the rotation of the second shell below the upper shell structure through the transmission structure inside the side shell. This rationally utilizes the internal space of the first shell without exposing the transmission structure outside the shell. All structures are enclosed by the shell, minimizing dust intrusion and improving the reliability of the lidar device in harsh operating environments. In this embodiment, a sensor plate 424 is also installed on the driving wheel, and a rotation sensor 143 for detecting the position of the sensor plate 424 is installed on the upper shell structure 112. This rotation sensor 143 is connected to the control device 2 and can be used to detect the position of the sensor plate in real time and then transmit the rotation angle and rotation data parameters of the driving wheel to the control device.

[0079] In this embodiment, as shown in the attached Figure 7As shown, the second shell 12 includes a main shell plate 123, and two side plates 124 and 125 perpendicular to the main shell plate 123 and respectively connected to the left and right ends of the main shell plate, and the two side plates are respectively connected to the corresponding side shell structures through the shell rotation shaft. The main shell plate 123 includes a first inclined plate 1231, a front plate 1232, a bottom plate 1233, a rear plate 1234 and a second inclined plate 1235 connected in sequence. The main shell plate 123 and the two side plates are surrounded to form an equipment chamber for installing a lidar device. The rear end of the first inclined plate 1231 is connected to the front end of the front plate 1232 and is bent toward the second inclined plate 1235. The front end of the second inclined plate 1235 is connected to the rear end of the front plate 1232 and is bent toward the first inclined plate 1231. By installing two inclined plates in front and behind the light source window on the main shell, when the LiDAR device is not in operation, the light source window of the second shell is rotated upward into the installation space. Most of the dust that falls from the second shell will settle on the first and second inclined plates. Once it accumulates to a certain level, it will slide down the inclined plates, thus ensuring that the second shell is as clean as possible. At the same time, by setting the front and rear ends of the light source window as inclined surfaces, the second shell can be installed as close as possible to the bottom of the upper shell structure of the first shell, effectively reducing the height of the entire LiDAR bracket.

[0080] In this embodiment, as shown in the attached Figure 8 As shown, the two side plates of the second shell are respectively provided with a first groove 1241 and a second groove 1251 inward at one end away from the bottom plate, and the two sides of the notch of the first groove 1241 are respectively connected to the first inclined plate 1231 and the second inclined plate 1235, and the two sides of the notch of the second groove 1251 are also respectively connected to the first inclined plate 1231 and the second inclined plate 1235, and the first groove 1241, the second groove 1251, the front end of the first inclined plate 1231 and the rear end of the second inclined plate 1235 surround to form a light source window 122 for the light beam of the laser radar device 3 to pass through.

[0081] In a specific preferred embodiment, the first inclined plate 1231 includes a first inclined portion 101 and a first flat portion 102 connected front to back. The rear end of the first flat portion 102 connects to the front end of the front plate 1232 and bends toward the second inclined plate 1235. The first flat portion 102 is positioned parallel to the bottom of the upper shell structure 112. The second inclined plate 1235 includes a second inclined portion 201 and a second flat portion 202 connected front to back. The front end of the second inclined portion 201 connects to the rear end of the front plate 1232 and bends toward the first inclined plate 1231. The second flat portion 202 is positioned parallel to the bottom of the upper shell structure 1112. The first groove 1241, the second groove 1251, the front end of the first flat portion 102, and the rear end of the second flat portion 202 surround and form the light source window 122 through which the laser radar device's light beam passes. The inclined first and second grooves allow the side opening of the light source window to be sufficiently long, providing a wider light source window for the laser radar.

[0082] In this embodiment, as shown in the attached Figure 9 As shown, the second housing 12 also includes a mounting base 126 for mounting the laser radar device. The mounting base 126 comprises a base 1261 and side frames 1262 mounted on either side of the base. A housing shaft is mounted on each side of the two side frames. Each side panel has a mounting channel 1263 for the corresponding housing shaft to pass through. The side panels are connected to the side frames via fasteners. The first groove 1241 is inclined toward the second inclined plate 1235. The second groove has the same shape and orientation as the first groove. The first inclined plate is longer than the second inclined plate. The base is fixed to the side panels at an angle relative to the bottom plate via the side frames. The base and the side frames formed a space for mounting the laser radar. The laser radar can be secured to the base or side frames via fasteners. A housing shaft is mounted on the outside of each side frame. The shaft passes through the mounting channel and is rotatably connected to the bearing inside the side shell structure. The mounting base within the housing provides a more stable installation of the laser radar.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0084] In short, the above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the patent of the present invention.

Claims

1. A multi-line laser radar system for acquiring large-scale point cloud data, characterized in that: include: Multi-line laser scanner; A radar bracket includes a first housing, a second housing for mounting a multi-line laser scanner, and a servo motor mounted within the first housing. The first housing defines a housing space for accommodating the second housing. The second housing is mounted within the housing space via a housing shaft and is rotatable relative to the first housing under the drive of the servo motor. The second housing defines a light source window for transmitting a light beam from the multi-line laser scanner mounted therein. The light source window can move in and out of the housing space as the second housing rotates. a control device electrically connected to the multi-line laser scanner and the servo motor, respectively, and configured to obtain the distance value, horizontal angle, and serial number of each single-point laser from the scanner, convert the data of each single-point laser obtained from the scanner from polar coordinates into data in a bracket coordinate system based on the rotation angle and speed of the housing shaft driven by the servo motor, and synthesize point cloud data of the laser scanner in the bracket coordinate system, wherein the bracket coordinate system has the axis of the housing shaft as its origin, and the axis of the housing shaft is perpendicular to the X-axis of the bracket coordinate system and the X-axis of the radar coordinate system; The control device is further configured to obtain the angle value Vn of the vertical angle of the bracket of the single-point laser data of the nth point, where v n =(p / ((p / 360°) / s*m-1)*n), where p is the operating angle of the shell shaft, s is the operating speed of the shell shaft, and m is the number of single-point lasers emitted by the multi-line laser scanner per second.

2. The multi-line laser radar system for acquiring large-scale point cloud data according to claim 1, characterized in that: The control device is also configured to convert each single point laser data obtained from the scanner from the radar polar coordinate system x'y'z'o' into data in the bracket coordinate system XYZO (X n Y n Z n ),in AND n =d n *cos t n *sina n ; where X n is the x value of the single point laser at point n in the bracket coordinate system, and Y n is the y value of the single point laser at point n in the bracket coordinate system, Z n is the z value of the single point laser at point n in the bracket coordinate system, d n is the distance value of the single-point laser data at point n, t n is the vertical angle value of the single-point laser data at point n, a n is the horizontal angle value of the single-point laser data at point n, v n is the vertical angle value of the single-point laser data of the nth point in the bracket, n is the variable value of the nth point, A is the Y component of the zero point of the radar polar coordinate system in the bracket coordinate system, and B is the X component of the zero point of the radar polar coordinate system in the bracket coordinate system.

3. The multi-line laser radar system for acquiring large-scale point cloud data according to claim 1, characterized in that: The control device is further configured to convert each single point laser data obtained from the scanner from polar coordinates into data in the bracket coordinate system according to the rotation angle and speed of the housing shaft driven by the servo motor, and synthesize the point cloud data (X n Y n Z n ): AND n =d n *cos t n *without a n ; where X n is the x value of the single point laser at point n in the bracket coordinate system, and Y n is the y value of the single point laser at point n in the bracket coordinate system, Z n is the z value of the single point laser at point n in the bracket coordinate system, d n is the distance value of the single-point laser data at point n, t n is the vertical angle value of the single-point laser data at point n, a n is the horizontal angle value of the single-point laser data at point n, v n is the vertical angle value of the single-point laser data of the nth point in the bracket, n is the variable value of the nth point, A is the Y component of the zero point of the radar polar coordinate system in the bracket coordinate system, B is the X component of the zero point of the radar polar coordinate system in the bracket coordinate system, p is the operating angle of the shell shaft, s is the operating speed of the shell shaft, and m is the number of single-point lasers emitted by the multi-line laser scanner per second.

4. The multi-line laser radar system for acquiring large-scale point cloud data according to claim 3, characterized in that: The radar bracket also includes a transmission structure connecting the servo motor and the shell rotating shaft. The first shell includes an upper shell structure with a servo motor installed inside and side shell structures fixed on both sides of the upper shell structure. The upper parts of the two side shell structures are respectively connected to the two sides of the upper shell structure, and the inner sides of the lower parts of the two side shell structures and the lower side of the upper shell structure are surrounded by an unclosed placement space, wherein a transmission structure with two ends connected to the servo motor and the shell rotating shaft is installed in one side shell structure; the transmission structure includes a driving wheel, a driven wheel and a synchronous belt connecting the driving wheel and the driven wheel installed in one side shell structure, the driving wheel is connected to the servo motor drive shaft, and the driven wheel is connected to a shell rotating shaft.

5. The multi-line laser radar system for acquiring large-scale point cloud data according to claim 4, characterized in that: The second shell includes a main shell plate, and two side plates perpendicular to the main shell plate and respectively connected to the left and right ends of the main shell plate, and the two side plates are respectively connected to the corresponding side shell structures through the shell rotating shaft. The main shell plate includes a first inclined plate, a front plate, a bottom plate, a rear plate and a second inclined plate connected in sequence. The main shell plate and the two side plates are surrounded to form an equipment chamber for installing the laser radar equipment. The rear end of the first inclined plate is connected to the front end of the front plate and is bent towards the second inclined plate. The front end of the second inclined plate is connected to the rear end of the front plate and is bent towards the first inclined plate.

6. The multi-line laser radar system for acquiring large-scale point cloud data according to claim 5, characterized in that: The two side plates are respectively provided with a first groove and a second groove inward at one end away from the bottom plate. The two sides of the notch of the first groove are respectively connected to the first inclined plate and the second inclined plate, and the two sides of the notch of the second groove are also respectively connected to the first inclined plate and the second inclined plate. The first groove, the second groove, the front end of the first inclined plate and the rear end of the second inclined plate surround to form a light source window for the light beam of the laser radar equipment to pass through.

7. The multi-line laser radar system for acquiring large-scale point cloud data according to claim 6, characterized in that: The first inclined plate includes a first inclined portion and a first flat portion connected front and back, the rear end of the first flat portion is connected to the front end of the front plate and is bent towards the second inclined plate, and the first flat portion is arranged parallel to the bottom of the upper shell structure; the second inclined plate includes a second inclined portion and a second flat portion connected front and back, the front end of the second inclined portion is connected to the rear end of the front plate and is bent towards the first inclined plate, and the second flat portion is arranged parallel to the bottom of the upper shell structure; the first groove, the second groove, the front end of the first flat portion and the rear end of the second flat portion surround to form a light source window for the light beam of the laser radar equipment to pass through.

8. The multi-line laser radar system for acquiring large-scale point cloud data according to claim 7, characterized in that: The second housing further includes a mounting base for mounting the laser radar device, the mounting base including a base and side frames mounted on both sides of the base, housing shafts being mounted on both sides of the two side members, and mounting channels for the corresponding housing shafts to pass through being provided on the two side plates, the side plates being connected to the side frames via fasteners; The first groove is inclined toward the second inclined plate, the shape and arrangement direction of the second groove are consistent with the first groove, the length of the first inclined plate is greater than that of the second inclined plate, and the base is fixed to the side plate by a side frame with respect to the bottom plate.

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