A multi-laser-radar-fusion-based ship loader blind area measurement system and method

Abstract

This invention provides a blind-spot-free measurement system and method for ship loaders using multi-LiDAR fusion, relating to the field of LiDAR measurement. The system includes: a ship hull, a multi-LiDAR fusion measurement device, a ship loader, and a robotic arm. The robotic arm clamps the upper end of the multi-LiDAR fusion measurement device. The robotic arm is movably mounted on the ship loader, its movement path running from the bow to the stern of the ship, always positioned on the centerline above the hull. This invention longitudinally mounts two long-range LiDARs and equips them with high-precision gimbals. By rotating the gimbals at low speed and small angles, dynamic stitching of the scan data is achieved, enabling rapid acquisition of accurate point cloud data in a short time, greatly improving data acquisition efficiency and accuracy. Through the installation of two long-range LiDARs and the cooperation of two short-range LiDARs, blind-spot-free measurement of the ship hull is achieved.

Description

Technical Field

[0001] This invention relates to the field of lidar measurement, and in particular to a blind-spot-free measurement system and method for ship loaders using multi-lidar fusion. Background Technology

[0002] Ship loaders are large mechanical devices used in ports to load bulk materials or general cargo onto ships. The accuracy and efficiency of their operation directly affect the port's throughput and operating costs. Traditional ship loader operation relies on manual experience, which is insufficient to meet the growing demands of modern ports. Early research on visual measurement for ship loaders focused primarily on simple material monitoring, using cameras to obtain approximate material accumulation at hoppers or conveyor belts to assist operators in determining whether to adjust loading speed or perform equipment maintenance. The introduction of lidar visual measurement technology enables ship loaders to perceive the surrounding environment, material status, and ship position in real time, opening new avenues for automated and intelligent operations and gradually expanding towards ship position identification and precise material flow measurement. However, existing lidar measurement methods still have the following shortcomings:

[0003] The mechanism-driven 2D LiDAR scanning and point cloud stitching method uses a 2D LiDAR combined with a mechanically driven mechanism to scan and acquire point cloud data from multiple angles. This data is then stitched together into a complete ship hull model using a 3D reconstruction algorithm. While this method offers high flexibility, its detection results are easily affected by occlusion from objects such as chutes. Furthermore, this method has a slow scanning speed and low resolution, failing to meet the real-time and precise positioning requirements of dynamic ship loader operations.

[0004] The lateral long-range lidar solution scans the hull from above and stitches together point cloud data using a lateral long-range lidar, offering advantages such as wide coverage and relatively simple installation. However, data from critical areas like the bow and stern is missing due to obstructions from ship loader structures such as chutes and conveyor belt supports. Furthermore, the upward scanning angle results in incomplete point cloud information for material piles in open hatches, affecting measurement accuracy. Additionally, the limited scanning speed of a single lidar unit makes it difficult to meet the demands of dynamic operations.

[0005] Multi-radar data stitching solutions deploy multiple lidar units and use data fusion algorithms to stitch together the point clouds collected by each lidar unit into a complete 3D model, making them suitable for use in environments with obstructions. However, an excessive number of lidar units can increase the complexity of the entire system and affect its stability.

[0006] In summary, the three methods—mechanism-driven 2D LiDAR, laterally mounted long-range LiDAR, and multi-radar data stitching—all have limitations. The above solutions cannot simultaneously address the following challenges:

[0007] 1. Scanning Speed: Ship loading operations are dynamic and continuous, requiring the lidar measurement system to have strong real-time performance and rapid feedback on changes in the ship and materials. However, some high-precision measurement methods, such as 2D laser scanning and 3D reconstruction technology, have slow scanning speeds that cannot keep up with the pace of the ship loader. When the state of the ship or materials changes, the measurement system updates data slowly, making it difficult for operators to adjust strategies based on real-time data. This results in low operational efficiency, increased error rates, and negatively impacts port profitability.

[0008] 2. Measurement Accuracy: Due to the long longitudinal length of the hull, the bow and stern are far from the lidar of the loading machine. Long-distance lidar measurements are affected by energy attenuation and angular resolution, making it difficult to capture subtle structural changes at the bow and stern, thus hindering high-precision measurement of the hull's attitude and limiting the accuracy and precision of loading operations.

[0009] 3. Sluice Box Obstruction: The complex structure of ship loaders, along with components such as sluice boxes and conveyor belt supports, often obstructs the line of sight of the lidar, adding challenges to measurements. A single lidar unit lacks multi-angle information; when obstructed, critical areas of the target easily fall into "detection blind spots," resulting in incomplete measurement data that fails to reflect the true state. Even when multiple lidar units are combined, complex obstructions can lead to missing data or increased errors in certain areas, affecting overall data quality and creating difficulties for subsequent processing and analysis.

[0010] 4. Arm Rotation: The rotation of the ship loader's arm significantly affects the lidar's field of view, potentially causing the ship to move out of the lidar's observation range. If too few lidar units are configured, it will be difficult to achieve effective coverage of the entire ship; however, if too many lidar units are configured (more than 6), it will place a heavy burden on the entire system, thereby affecting the system's stability.

[0011] 5. Complex Environment: The port operation environment is complex and ever-changing. Material dust is present in the air year-round, posing an extremely severe challenge to lidar vision measurement equipment. Low-cost, short-range lidar is particularly sensitive to dust. Dust particles not only significantly weaken the intensity of the laser signal but may also cause false triggering, resulting in a sharp decline in the stability and accuracy of its measurements. Summary of the Invention

[0012] In view of this, the purpose of this invention is to provide a blind-spot-free measurement system and method for ship loaders using multi-LiDAR fusion, which solves the problems of slow scanning speed, low measurement accuracy, obstruction by the chute, and the influence of boom rotation and complex environment on measurement accuracy in existing LiDAR measurement methods.

[0013] This invention provides a blind-spot-free measurement system for ship loaders based on multi-lidar fusion, comprising:

[0014] Hull, multi-lidar fusion measurement device, ship loader and robotic arm;

[0015] The robotic arm grips the upper part of the multi-LiDAR fusion measurement device;

[0016] The robotic arm is movably mounted on the ship loader. The robotic arm moves from the bow to the stern of the ship and is always positioned on the centerline above the ship.

[0017] Preferred:

[0018] The multi-LiDAR fusion measurement device includes: a first long-range LiDAR, a second long-range LiDAR, a first short-range LiDAR, a second short-range LiDAR, a first gimbal, a second gimbal, a slide base, and a slide;

[0019] The upper end of the chute is fixedly connected to the center of the lower surface of the chute base, and the upper surface of the chute base is connected to the robotic arm.

[0020] The first and second gimbals are symmetrically arranged on the lower surface of the chute base with the chute as the center. The first long-range lidar is set on the first gimbal, and the second long-range lidar is set on the second gimbal.

[0021] The first and second short-range lidars are symmetrically arranged on the lower surface of the chute base with the chute as the center.

[0022] The relative positions of the first short-range lidar, the second short-range lidar, the first gimbal, and the second gimbal remain unchanged.

[0023] Preferred:

[0024] One of the first long-range lidar and the second long-range lidar are pointed towards the shore side of the ship's hull, and the other is pointed towards the sea side of the ship's hull.

[0025] Preferred:

[0026] One of the first and second short-range lidars is pointed towards the bow of the ship, and the other is pointed towards the stern.

[0027] Preferred:

[0028] The rotation axes of the first and second long-range lidars are perpendicular to the direction of the ship's hull from bow to stern.

[0029] Preferred:

[0030] The rotation axes of the first and second gimbals are parallel to the direction of the ship's hull from bow to stern.

[0031] The rotation axis of the first gimbal is perpendicular to the rotation axis of the first long-range lidar, and the rotation axis of the second gimbal is perpendicular to the rotation axis of the second long-range lidar.

[0032] Preferred:

[0033] When the multi-LiDAR fusion measurement device moves, the first gimbal controls the first long-range LiDAR to rotate around the axis of the ship's bow to stern, and the second gimbal controls the second long-range LiDAR to rotate around the axis of the ship's bow to stern, so that the first and second long-range LiDARs move along a sinusoidal trajectory.

[0034] Preferred:

[0035] The rotation axes of the first and second short-range lidars point vertically downwards towards the horizontal sea surface.

[0036] A method for blind-spot-free measurement of ship loaders using multi-lidar fusion, based on the aforementioned blind-spot-free measurement system for ship loaders, includes the following steps:

[0037] S1: Activate the multi-laser radar fusion measurement device, and make the multi-laser radar fusion measurement device move back and forth between the bow and stern of the ship. Control the first long-range laser radar and the second long-range laser radar to move in a sinusoidal trajectory through the first gimbal and the second gimbal.

[0038] S2: Obtain the initial point cloud at the current moment using the first long-range lidar, the second long-range lidar, the first short-range lidar, and the second short-range lidar;

[0039] S3: Obtain the rotation and translation matrices of the multi-LiDAR fusion measurement device at the current moment, and construct the homogeneous transformation matrix at the current moment using the rotation and translation matrices at the current moment;

[0040] S4: Calculate the updated point cloud at the current time using the initial point cloud and the homogeneous transformation matrix at the current time, and construct the 3D hull model at the current time using the updated point cloud at the current time.

[0041] S5: Repeat steps S2-S4 to update the 3D hull model in real time.

[0042] Preferred:

[0043] The expression for updating the point cloud at the current moment is: ΔT(θ) i )·Pts i ;

[0044] Where i represents the current time, Pts i Let ΔT(θ) represent the initial point cloud at the current time. i Let θ represent the homogeneous transformation matrix at the current time step. i This indicates the current angle of gimbal rotation.

[0045]

[0046] Among them, R i Let t represent the rotation matrix at the current time. i This represents the translation matrix at the current moment.

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

[0048] 1. Two long-range lidar units are installed longitudinally and equipped with high-precision gimbals. By rotating the gimbals at low speed and small angle, the scanning data can be dynamically stitched together, which can quickly acquire accurate point cloud data in a short time, greatly improving the efficiency and accuracy of data acquisition.

[0049] 2. Two additional short-range lidar units were installed to specifically scan the blind spot around the chute, which is difficult for long-range lidar to reach. This filled the data gap and ensured that the ship could collect data from all directions without any blind spots. Furthermore, the scanning area could still steadily cover the hull during the boom rotation, ensuring the integrity and continuity of data collection.

[0050] 3. All four lidar units are mounted on the lower surface of the slide block, resulting in a large overlap in their scanning areas. This layout facilitates high-precision data stitching of the long-range lidar data in later stages, further optimizing data quality and making the final ship attitude information more accurate and reliable. Attached Figure Description

[0051] Figure 1 This is a structural diagram of a multi-LiDAR fusion measurement device;

[0052] Figure 2 A schematic diagram showing a long-range lidar scan being obstructed;

[0053] Figure 3 A bottom view of a multi-laser radar fusion measurement device;

[0054] Figure 4 A schematic diagram of a multi-laser radar fusion measurement device scanning the hull;

[0055] Figure 5 This is a schematic diagram of the gimbal's movement;

[0056] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0058] This invention provides a blind-spot-free measurement system for ship loaders based on multi-lidar fusion, comprising:

[0059] Hull, multi-lidar fusion measurement device, ship loader and robotic arm;

[0060] The robotic arm grips the upper part of the multi-LiDAR fusion measurement device;

[0061] The robotic arm is movably mounted on the ship loader. The robotic arm moves from the bow to the stern of the ship and is always positioned on the centerline above the ship.

[0062] As one embodiment, a multi-LiDAR fusion measurement device, such as Figure 1 As shown:

[0063] The multi-LiDAR fusion measurement device includes: a first long-range LiDAR 1, a second long-range LiDAR 2, a first short-range LiDAR 3, a second short-range LiDAR 4, a first gimbal 5, a second gimbal 6, a slide base 7, and a slide 8;

[0064] The upper end of the chute 8 is fixedly connected to the center of the lower surface of the chute base 7, and the upper surface of the chute base 7 is connected to the robotic arm.

[0065] The first gimbal 5 and the second gimbal 6 are symmetrically arranged on the lower surface of the chute seat 7 with the chute 8 as the center. The first long-range lidar 1 is arranged on the first gimbal 5 and the second long-range lidar 2 is arranged on the second gimbal 6.

[0066] The first short-range lidar 3 and the second short-range lidar 4 are symmetrically arranged on the lower surface of the chute seat 7 with the chute 8 as the center.

[0067] The relative positions of the first short-range lidar 3, the second short-range lidar 4, the first gimbal 5, and the second gimbal 6 remain unchanged.

[0068] As one example:

[0069] One of the first long-range lidar 1 and the second long-range lidar 2 points towards the shore side of the ship's hull, while the other points towards the sea side of the ship's hull.

[0070] Specifically, longitudinally mounted long-range lidar is chosen because its scanning area exhibits the characteristic of being smaller near the radar end and larger far from it (longitudinally mounted long-range lidar has a significant characteristic: within the same horizontal plane, the area near the radar end is narrow, while the area far from the radar end is wide, exhibiting a near-small and far-large pattern, and the boundary of this area follows the rule of quadratic curve variation. At the same time, as the scanning distance gradually increases, the resolution of the point cloud collected by the radar decreases sharply, that is, the farther the distance, the more blurred the details of the point cloud and the lower the accuracy), and its boundary exhibits the variation law of quadratic curve. Therefore, even with many variables during the boom rotation, the scanning area can still stably cover the hull.

[0071] As one example:

[0072] One of the first short-range lidar 3 and the second short-range lidar 4 is pointed at the bow of the ship, and the other is pointed at the stern of the ship.

[0073] As one example:

[0074] The rotation axes of the first long-range lidar 1 and the second long-range lidar 2 are perpendicular to the direction of the ship's hull from bow to stern.

[0075] Specifically, long-range lidar must meet the following technical specifications: the horizontal scanning coverage must be no less than 180°, the vertical scanning range must be no narrower than 42°, the number of lines must be at least 128, and the effective ranging distance must exceed 180 meters. Installation requirements are as follows: When the rotating arm of the ship loader is driven so that the chute 8 is directly above the centerline of the reference ship type, the horizontal scanning direction of the long-range lidar should be parallel to the axis from bow to stern, and its rotation axis should be perpendicular to the dockside.

[0076] As one example:

[0077] The rotation axis of the first gimbal 5 and the second gimbal 6 are parallel to the direction of the ship's hull from bow to stern.

[0078] The rotation axis of the first gimbal 5 is perpendicular to the rotation axis of the first long-range lidar 1, and the rotation axis of the second gimbal 6 is perpendicular to the rotation axis of the second long-range lidar 2.

[0079] Specifically, each long-range lidar unit's base needs to be individually and securely mounted on a corresponding high-precision, one-degree-of-freedom rotating gimbal, which is then reliably mounted on the slide block 7. This rotating gimbal possesses high precision characteristics, with its rotation speed flexibly adjustable within the range of 0.1° to 1° / second. Furthermore, the direction of its rotation axis is parallel to the direction from bow to stern and precisely perpendicular to the rotation axis of the long-range lidar, ensuring that the long-range lidar can perform flexible and accurate azimuth adjustments.

[0080] As one example:

[0081] When the multi-LiDAR fusion measurement device moves, the first gimbal 5 controls the first long-range LiDAR 1 to rotate around the direction from the bow to the stern of the ship as the axis, and the second gimbal 6 controls the second long-range LiDAR 2 to rotate around the direction from the bow to the stern of the ship as the axis, so that the first long-range LiDAR 1 and the second long-range LiDAR 2 move along a sine wave trajectory.

[0082] As one example:

[0083] The rotation axes of the first short-range lidar 3 and the second short-range lidar 4 point vertically downwards toward the horizontal sea surface.

[0084] Specifically, two additional short-range lidar units are symmetrically installed on both sides of the chute 8, one facing the bow and the other the stern. Both are stationary relative to the chute base 7 and do not require mounting on a pan-tilt unit. The technical parameters of these two short-range lidar units are: a horizontal scanning range of 360°, a vertical scanning range of at least 60°, and a ranging distance of at least 50 meters. After installation, the rotation axis of the short-range lidar points vertically downwards towards the horizontal ground, ensuring that its detection angle can cover the surrounding environment omnidirectionally and without blind spots. This provides accurate and reliable monitoring data for the overall operation, thus avoiding issues such as... Figure 2 The problem shown is that the scan of a single long-range lidar is obstructed.

[0085] As one example:

[0086] The specific installation methods for the first long-range lidar 1, the second long-range lidar 2, the first short-range lidar 3, the second short-range lidar 4, the first gimbal 5, and the second gimbal 6 are not unique. They can be stably fixed to the slide block base 7 according to the actual working conditions, ensuring the aforementioned directional requirements are met. A bottom view of the multi-lidar fusion measurement device is shown below. Figure 3 As shown, the base of the first long-range lidar 1 is fixed on the high-precision gimbal 5, and the high-precision gimbal 5 is fixed on the slide block 7. The two short-range lidars are directly and stably fixed on the slide block 7. The distance between the first long-range lidar 1, the second long-range lidar 2, the first short-range lidar 3 and the second short-range lidar 4 can be adjusted according to the actual situation to reduce the installation difficulty of each component.

[0087] This invention provides a blind-spot-free measurement method for ship loaders based on multi-lidar fusion, implemented using the aforementioned blind-spot-free measurement system for ship loaders, comprising the following steps:

[0088] S1: Start the multi-laser radar fusion measurement device, and make the multi-laser radar fusion measurement device move back and forth between the bow and stern of the ship, and control the first long-range laser radar 1 and the second long-range laser radar 2 to move in a sine wave trajectory through the first gimbal 5 and the second gimbal 6.

[0089] Specifically, S11: Sluice box positioning: Move the sluice box of the ship loader to directly above the empty ship, ensuring that the sluice box is aligned with the centerline of the ship;

[0090] S12: Radar Activation: Activate the four lidars (two long-range and two short-range) mounted on the slide block and initiate the initial scan;

[0091] S13: Gimbal and LiDAR Clock Synchronization: The gimbal is moved along a sinusoidal trajectory while the position of the target object in the point cloud data collected by the LiDAR is observed synchronously. Based on this positional information, an algorithm is used to fit a curve showing the change of the target object's position over time. Then, the motion curve of the gimbal is compared and matched with the motion curve of the target object in the point cloud data, and fine-tuning is performed on key parameters such as the phase, frequency, and amplitude of the curves. Through this process, the clocks of the gimbal and the LiDAR are synchronized, ensuring their time-level coordination and laying a solid foundation for subsequent accurate data acquisition and analysis.

[0092] S2: Obtain the initial point cloud at the current moment through the first long-range lidar 1, the second long-range lidar 2, the first short-range lidar 3, and the second short-range lidar 4;

[0093] Specifically, S21: Basic point cloud generation: Four radars simultaneously collect point cloud data of the hull and surrounding environment to generate a basic 3D model; since this is based on a single viewpoint scan, some areas may be obscured by chutes or other structures, resulting in voids inside the generated model.

[0094] S22: Dynamic scanning and stitching: When switched to automatic operation mode, the system will automatically control the chute to move to the bow position, and then perform a series of detailed visual scans of the hull from bow to stern.

[0095] S23: Gimbal Motion Control: During the scanning process, the system drives the high-precision gimbal mounted on the long-range lidar to perform small-angle (0.1°~1°) micro-motion according to the preset sine wave trajectory. This process only takes 1 second. During the gimbal movement, a series of single-frame point cloud data are continuously collected and stitched together to obtain accurate high-resolution point clouds, thereby improving the accuracy of the long-range lidar.

[0096] S24: After scanning, the acquired scan results are stitched together to obtain a precise and complete 3D model. In this method, by using close-range radar to fill in locally obscured areas, the entire hull can be modeled, such as... Figure 4 As shown, because the scanning viewpoint achieves full coverage and there are no blind spots, the constructed ship hull model will not have any hollow phenomena.

[0097] S3: Obtain the rotation and translation matrices of the multi-LiDAR fusion measurement device at the current moment, and construct the homogeneous transformation matrix at the current moment using the rotation and translation matrices at the current moment;

[0098] Specifically, the spatial calibration of the gimbal and lidar involves: first, setting the initial angle θ0 of the gimbal and acquiring the corresponding initial point cloud Pts0. Next, driving the gimbal to a series of specific angles θ0, and simultaneously acquiring a series of point cloud frames {Pts} at each angle. i}, where i = 1, 2, ..., N, and N is the number of samples, generally not less than 3. Subsequently, point cloud 3D alignment technology is used for processing, aiming to obtain a value that meets Pts. i =ΔT(θ) i The transformation matrix of the relationship ΔT(θ)·Pts0. i ) is a 4×4 homogeneous transformation matrix. Compared to θ i The function can accurately describe the mathematical transformation relationship of point clouds at different angles. Finally, through the difference algorithm, the functional transformation relationship between θ and ΔT(θ) is derived. In this way, for any given value of θ, the corresponding accurate transformation matrix ΔT(θ) can be obtained based on the established transformation relationship, thus providing support for subsequent accurate point cloud processing and related applications;

[0099] S4: Calculate the updated point cloud at the current time using the initial point cloud and the homogeneous transformation matrix at the current time, and construct the 3D hull model at the current time using the updated point cloud at the current time.

[0100] Specifically, improving the accuracy of long-range LiDAR: Expanding the scanning coverage through slight gimbal movements, combined with sinusoidal trajectory fitting, and stitching together data within one second to obtain a higher-precision point cloud. For example... Figure 5 As shown, during the gimbal movement, each frame of point cloud Pts is acquired. i Based on the point cloud timestamp and the gimbal timestamp, the most matching gimbal rotation angle θ is precisely found. i Next, calculate the corresponding 4×4 homogeneous transformation matrix ΔT(θ). i The current point cloud is transformed using this transformation matrix to obtain a new point cloud ΔT(θ). i )·Pts i Finally, the transformed point clouds are stitched together to obtain a high-resolution point cloud.

[0101] S5: Repeat steps S2-S4 to update the 3D hull model in real time.

[0102] Specifically, during the actual loading process, once there is a need to update the real-time status of the ship, the updated ship model can be obtained immediately, ensuring accurate control over the dynamic changes in the ship's position and the real-time changes in the volume of materials, thus providing a strong guarantee for the smooth progress of the loading operation.

[0103] As one example:

[0104] The expression for updating the point cloud at the current moment is: ΔT(θ) i )·Pts i ;

[0105] Where i represents the current time, Pts i Let ΔT(θ) represent the initial point cloud at the current time. i Let θ represent the homogeneous transformation matrix at the current time step. i This indicates the current angle of gimbal rotation.

[0106]

[0107] Among them, R i Let t represent the rotation matrix at the current time. i This represents the translation matrix at the current moment.

[0108] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0109] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the unit claims listing several devices, several of these devices may be embodied by the same hardware item. The use of the terms first, second, and third, etc., does not indicate any order and can be interpreted as identifiers.

[0110] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A blind-spot-free measurement system for ship loaders using multi-lidar fusion, characterized in that, include: Hull, multi-lidar fusion measurement device, ship loader and robotic arm; The robotic arm grips the upper part of the multi-LiDAR fusion measurement device; The robotic arm is movably mounted on the ship loader. The robotic arm moves from the bow to the stern of the ship and is always located on the centerline above the ship. The multi-laser radar fusion measurement device includes: a first long-range laser radar (1), a second long-range laser radar (2), a first short-range laser radar (3), a second short-range laser radar (4), a first gimbal (5), a second gimbal (6), a duct mount (7), and a duct (8); The upper end of the chute (8) is fixedly connected to the center of the lower surface of the chute seat (7), and the upper surface of the chute seat (7) is connected to the robotic arm. The first gimbal (5) and the second gimbal (6) are symmetrically arranged on the lower surface of the chute seat (7) with the chute (8) as the center. The first long-range laser radar (1) is set on the first gimbal (5) and the second long-range laser radar (2) is set on the second gimbal (6). The first short-range lidar (3) and the second short-range lidar (4) are symmetrically arranged on the lower surface of the chute seat (7) with the chute (8) as the center; The relative positions of the first near-range lidar (3), the second near-range lidar (4), the first gimbal (5), and the second gimbal (6) remain unchanged; One of the first long-range lidar (1) and the second long-range lidar (2) points to the shore side of the ship's hull, and the other points to the sea side of the ship's hull; One of the first short-range lidar (3) and the second short-range lidar (4) is pointed towards the bow of the ship, and the other is pointed towards the stern of the ship.

2. The blind-spot-free measurement system for ship loaders based on multi-lidar fusion as described in claim 1, characterized in that: The rotation axes of the first long-range lidar (1) and the second long-range lidar (2) are perpendicular to the direction of the ship's hull from bow to stern.

3. The multi-lidar fusion ship loader blind-spot-free measurement system according to claim 2, characterized in that: The rotation axis of the first gimbal (5) and the second gimbal (6) is parallel to the direction of the ship's bow to stern. The rotation axis of the first gimbal (5) is perpendicular to the rotation axis of the first long-range lidar (1), and the rotation axis of the second gimbal (6) is perpendicular to the rotation axis of the second long-range lidar (2).

4. The blind-spot-free measurement system for ship loaders based on multi-lidar fusion as described in claim 3, characterized in that: When the multi-laser fusion measurement device moves, the first gimbal (5) controls the first long-range laser radar (1) to rotate around the direction from the bow to the stern of the ship, and the second gimbal (6) controls the second long-range laser radar (2) to rotate around the direction from the bow to the stern of the ship, so that the first long-range laser radar (1) and the second long-range laser radar (2) move along a sine wave trajectory.

5. The blind-spot-free measurement system for ship loaders based on multi-lidar fusion according to claim 1, characterized in that: The rotation axes of the first short-range lidar (3) and the second short-range lidar (4) point vertically downwards toward the horizontal sea surface.

6. A method for blind-spot-free measurement of ship loaders using multi-LiDAR fusion, implemented based on the multi-LiDAR fusion blind-spot-free measurement system for ship loaders as described in any one of claims 1-5, characterized in that, Including the following steps: S1: Start the multi-laser radar fusion measurement device, and make the multi-laser radar fusion measurement device move back and forth between the bow and stern of the ship. Control the first long-range laser radar (1) and the second long-range laser radar (2) to move in a sinusoidal trajectory through the first gimbal (5) and the second gimbal (6). S2: Obtain the initial point cloud at the current moment through the first long-range lidar (1), the second long-range lidar (2), the first short-range lidar (3), and the second short-range lidar (4); S3: Obtain the rotation and translation matrices of the multi-LiDAR fusion measurement device at the current moment, and construct the homogeneous transformation matrix at the current moment using the rotation and translation matrices at the current moment; S4: Calculate the updated point cloud at the current time using the initial point cloud and the homogeneous transformation matrix at the current time, and construct the 3D hull model at the current time using the updated point cloud at the current time. S5: Repeat steps S2-S4 to update the 3D hull model in real time.

7. The blind-spot-free measurement method for ship loaders using multi-lidar fusion as described in claim 6, characterized in that: The expression for updating the point cloud at the current moment is: ； Where i represents the current time, This represents the initial point cloud at the current moment. This represents the homogeneous transformation matrix at the current time. This indicates the current angle of gimbal rotation. in, This represents the rotation matrix at the current moment. This represents the translation matrix at the current moment.

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