Main hook motion measurement system and method for a large hoisting vessel

Abstract

The present invention discloses a main hook motion measurement system and method for a large lifting ship, which includes a lifting ship hull. An arm is provided on the lifting ship hull, and the arm is connected to a main hook through a suspension cable. There are two arms, and two main hooks are provided on each arm. The four main hooks are distributed in a rectangle. Two laser ranging radars are fixedly connected to the cross beam of each arm. The included angle formed by the connection line between the centers of the two laser ranging radars on the cross beam of each arm and the center of the cross beam of the arm is 60°. The two fan-shaped fields of view of the two laser ranging radars on the cross beam of each arm form a butterfly-shaped field of view. The field of view range of the butterfly-shaped field of view can completely cover the motion space of the main hook under various working conditions. The present invention uses high-precision laser ranging radars and intelligent three-dimensional information processing, not only making the measurement process automated, but also being able to intuitively and integrally view the overall motion states of the main hook, the lifting appliance, and the lifted object.

Description

Technical Field

[0001] The present invention relates to the technical field of crane vessels, and in particular to a main hook motion measurement system and method for a large crane vessel. Background Art

[0002] Large crane vessels are important equipment for water construction. From the overall hoisting of wind turbines to the overall lifting of large-section bridges to large pile driving operations, they are all inseparable from large lifting equipment. However, the efficiency of construction operations and the judgment of operation windows play a crucial part, and whether the main hook can reach the swing range for hoisting operations is the main judgment content. Currently, the observation of the main hook and the judgment of operation feasibility mainly rely on human eye observation, and it is experienced operators who rely on visual inspection and experience to judge whether the movement amplitude of the main hook meets the operation requirements. This observation method is relatively common, but there are large errors, and the judgment often tends to be conservative, and there are also many uncontrollable factors. There are few intelligent devices applied on traditional large crane vessels. With the development of technology, on the premise of ensuring accuracy, measurement will tend to be unmanned, providing auxiliary decision-making for operators, reducing the labor force in construction, and improving construction efficiency and window periods. Therefore, in view of the above problems, there is an urgent need to provide an intelligent measurement system and method for measuring the motion of the main hook of a large crane vessel. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a main hook motion measurement system and method for a large crane vessel in view of the defects in the prior art. It can not only provide intelligent auxiliary decision-making for judging the operation window period of construction operations, but also provide state monitoring of the suspended load during construction operations, reduce the manual labor volume and increase the measurement accuracy, realize the measurement of the real-time motion state of the 6 degrees of freedom of the main hook, generate a real-time three-dimensional model schematic animation of the main hook, and at the same time, the parameters of the suspended load and the lifting appliance can be input, and a real-time three-dimensional model schematic animation of the main hook, the lifting appliance, and the suspended load can be generated.

[0004] The technical solution adopted by the present invention to solve its technical problems is: The present invention provides a main hook motion measurement system for a large crane vessel, including a crane hull. An arm is provided on the crane hull, and the arm is connected to a main hook through a suspension cable. There are two arms, and two main hooks are provided on each arm. The four main hooks are distributed in a rectangle. Two laser rangefinders are fixedly connected to the cross beam of each arm. The included angle formed by the connection line between the centers of the two laser rangefinders on the cross beam of each arm and the center of the cross beam of the arm is 60°. The two fan-shaped fields of view of the two laser rangefinders on each arm form a butterfly-shaped field of view, and the field of view range of the butterfly-shaped field of view can completely cover the motion space of the main hook under various working conditions.

[0005] In a preferred embodiment of the present invention, two laser range finders are installed at the cross beam of each boom, which is 108 m away from the base.

[0006] In a preferred embodiment of the present invention, a bearing platform is connected to the cross beam of each boom through a mounting clamp, and two laser range finders are arranged on the bearing platform.

[0007] In a preferred embodiment of the present invention, the boom is a fixed boom, and the boom is arranged at the working position of the bow of the ship.

[0008] In a preferred embodiment of the present invention, one end of the lifting cable is connected to the lifting cable winch located on the lifting hull, and the other end is connected to the main hook.

[0009] The present invention also discloses a method for measuring the movement of the main hook of a large lifting ship, which obtains the three-dimensional point clouds of the four main hooks based on the four laser range finders; obtains the three-dimensional front view of the point clouds of the four main hooks based on the three-dimensional point clouds; obtains the three-dimensional coordinates of the movement of the main hook based on the three-dimensional front view of the point clouds and the FVNet algorithm of the target detection framework; and reconstructs and visualizes the movement field of the lifting hook based on the three-dimensional coordinates of the movement of the main hook.

[0010] In a preferred embodiment of the present invention, the specific steps include that when the four main hooks are in the empty hook working condition,

[0011] S1, the main console or the sub-console sends a measurement start signal;

[0012] S2, the laser range finder receives the signal from the main console or the sub-console and starts the laser emission work;

[0013] S3, the laser range finder emits lasers covering the entire designed range within the horizontal and vertical ranges;

[0014] S4, the laser range finder receives the laser reflected back by the main hook and processes and analyzes the reflected signal;

[0015] S5, the laser range finder converts the collected reflected signal into the position signal of the empty hook in the horizontal and vertical directions;

[0016] S6, the laser range finder transmits the position signal of the empty hook back to the main console and the sub-console;

[0017] S7, the main console and the sub-console display the position parameters of the empty hook, and process the signal into a three-dimensional model and display the current state in real time on the panels of the main console and the sub-console;

[0018] S8, accurately observe the real-time movement state of the 6 degrees of freedom of the main hook, and provide intelligent auxiliary decision-making for the main hook for judging the construction operation window period and predicting dangerous situations.

[0019] In a preferred embodiment of the present invention, when the intelligent auxiliary decision-making system detects that the angle between the swing of the empty hook and the vertical axis exceeds 15°, an alarm is triggered, and alarm messages are sent simultaneously to the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large and that the hull, boom, and wire rope length need to be adjusted to reduce the swing of the main hook.

[0020] In a preferred embodiment of the present invention, the specific steps include that when the four main hooks are in the working condition of lifting an object,

[0021] S1, the main console or the secondary console sends a measurement start signal;

[0022] S2, the laser ranging radar receives the signal from the main console or the secondary console and starts the laser emission work;

[0023] S3, the laser ranging radar emits laser within the horizontal and vertical ranges to cover the entire designed range;

[0024] S4, the laser ranging radar receives the laser reflected by the main hook and processes and analyzes the reflected signal;

[0025] S5, the laser ranging radar converts the collected reflected signal into the position signal of the empty hook in the horizontal and vertical directions;

[0026] S6, the laser ranging radar transmits the position signal of the empty hook back to the main console and the secondary console;

[0027] S7, the main console and the secondary console display the position parameters of the empty hook, process the signal into a three-dimensional model, and display the current state in real time on the panels of the main console and the secondary console. At the same time, the three-dimensional parameters of the lifted object and the lifting appliance and the relative positions of the main hook, the lifting appliance, and the lifted object are input into the panels of the main console or the secondary console, and the three-dimensional real-time state diagram of the lifted object is obtained through analysis;

[0028] S8, by accurately measuring the real-time motion state of the 6 degrees of freedom of the main hook, the real-time motion state of the 6 degrees of freedom of the lifted object is calculated, providing intelligent auxiliary decision-making for the lifting operation.

[0029] In a preferred embodiment of the present invention, during the lifting operation, the intelligent auxiliary decision-making system:

[0030] During single-boom operation, when the laser ranging radar detects that the angle between the swing of the two main hooks and the overall swing of the lifted object and the vertical axis exceeds 5°, an alarm is triggered, and alarm messages are sent simultaneously to the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large and that the hull, boom, and wire rope length need to be adjusted to reduce the swing of the main hook, or the main hook and the lifted object need to be lowered to a lower position;

[0031] When the double jib is in operation, when the laser ranging radar monitors that the included angle between the overall swing of the four main hooks and the suspended load and the vertical axis exceeds 5°, an alarm is triggered, and alarm messages are sent simultaneously on the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large. It is necessary to adjust the hull, jib, and wire rope length to reduce the swing of the main hook, or lower the main hook and the suspended load to a lower position.

[0032] The beneficial effects of the present invention are as follows: The present invention realizes unmanned measurement of the main hook, lifting tackle, and suspended load on a large crane ship. It can not only provide intelligent auxiliary decision-making for judging the construction operation window period, but also provide state monitoring of the suspended load during construction operations, reducing the manual labor intensity and increasing the measurement accuracy. It realizes the measurement of the real-time motion state of the 6 degrees of freedom of the main hook and generates a schematic animation of the real-time three-dimensional model of the main hook. At the same time, the parameters of the suspended load and lifting tackle can be input, and schematic animations of the real-time three-dimensional models of the main hook, lifting tackle, and suspended load can be generated. By using a high-precision laser ranging radar and intelligent three-dimensional information processing, the present invention not only automates the measurement process, but also enables an intuitive overall view of the overall motion states of the main hook, lifting tackle, and suspended load. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0034] Figure 1 is a butterfly-shaped field of view schematic diagram of the laser ranging radar of a main hook motion measurement system for a large crane ship according to an embodiment of the present invention;

[0035] Figure 2 is a field of view schematic diagram of the laser ranging radar of a main hook motion measurement system for a large crane ship according to an embodiment of the present invention;

[0036] Figure 3 is a field of view schematic diagram of the laser ranging radar of a main hook motion measurement system for a large crane ship according to an embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of the gear transmission mechanism of a main hook motion measurement system for a large crane ship according to an embodiment of the present invention;

[0038] Figure 5 is an assembly schematic diagram of the laser ranging radar of a main hook motion measurement system for a large crane ship according to an embodiment of the present invention;

[0039] Figure 6 is an assembly schematic diagram of the laser ranging radar of a main hook motion measurement system for a large crane ship according to an embodiment of the present invention;

[0040] In the figure: 1 - crane hull, 2 - jib, 3 - lifting cable, 4 - main hook, 5 - laser ranging radar installation point, 6 - living quarters, 7 - bow observation house, 8 - lifting tackle and the object being lifted, 9 - laser ranging radar, 10 - bearing platform. Detailed implementation manners

[0041] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] The present invention discloses a main hook motion measurement system for a large hoisting ship, which includes a hoisting hull 1. An arm 2 is provided on the hoisting hull 1. The arm 2 is connected to a main hook 4 through a suspension cable 3. There are two arms 2, and two main hooks 4 are provided on each arm 2. The four main hooks 4 are arranged in a rectangle. Two laser rangefinder radars 9 are fixedly connected to the cross beam of each arm 2. The included angle formed by the connection line between the centers of the two laser rangefinder radars 9 on the cross beam of each arm 2 and the center of the cross beam of this arm 2 is 60°. The two fan-shaped fields of view of the two laser rangefinder radars 9 on each arm 2 form a butterfly-shaped field of view, and the field of view range of the butterfly-shaped field of view can completely cover the motion space of the main hook 4 under various working conditions.

[0043] Preferably, the main definition of the large hoisting ship of the present invention is as follows: This ship is a large hoisting ship with double arms. Two main hooks are arranged front and back on each arm. The 4 main hooks of the whole ship are arranged in a rectangle. Two lidar radars are vertically installed on the platform at an included angle of 60 degrees. The platform is fixed to the cross beam through a special installation clamp. The arm is a fixed arm, a double arm, arranged at the bow operation part, and is the main operation equipment of the large hoisting ship.

[0044] Preferably, two laser rangefinder radars 9 are installed at the cross beam of the boom 108m away from the base.

[0045] Preferably, a platform 10 is connected to the cross beam of each arm 2 through an installation clamp, and two laser rangefinder radars 9 are arranged on the platform 10.

[0046] Preferably, the arm 2 is a fixed arm, and the arm 2 is arranged at the bow operation part.

[0047] Preferably, one end of the suspension cable 3 is connected to a suspension cable winch located on the hoisting hull 1, and the other end is connected to the main hook 4.

[0048] Preferably, the suspension cable winch is arranged below the A-frame. The cable passes through the connecting arm of the A-frame and passes through the guiding pulley at the lower end of the suspension cable platform at the upper end of the arm and hangs down naturally.

[0049] Preferably, the main hook is located at the front end of the suspension cable. Two main hooks and one auxiliary hook are arranged on a single arm. The two main hooks are arranged front and back.

[0050] Preferably, two lidar sensors are vertically installed on the console at an angle of 60°, and the console is fixed to the crossbeam by a special installation clamp. To ensure that the field of view of the lidar sensors can cover the space where the main hook moves, two lidar sensors are installed at the crossbeam 108 m away from the base of each boom. The two lidar sensors are vertically installed and arranged at an angle of 60°. Thus, the two fan-shaped fields of view of the two lidar sensors form a large butterfly-shaped field of view, and this butterfly-shaped field of view can completely cover the movement space of the main hook under various working conditions. The main working principle is that the laser of the lidar sensor emits a cluster of pulsed lasers to the wave surface. After the laser reaches an object (main hook) with a certain reflectivity, it is reflected back to the radar receiver. According to the laser ranging principle, the distance and azimuth angle from the radar to the target point can be obtained, and the overall movement of the measured object (main hook) can be determined.

[0051] Preferably, the main console is located in the captain's cabin and integrated into the panel of the ship intelligent auxiliary decision-making system, serving as the main decision-making center during the construction operation window period. The sub-console is located in the bow observation house, serving as the main observation point for measuring the movement of the main hook during construction operations and an auxiliary decision-making point for the construction operation window. The spreader and the object being lifted are located directly below the main hook and connected by the main hook, having a certain relative position with the main hook, and the relative position of the spreader and the object being lifted with respect to the main hook is relatively stable.

[0052] The present invention also discloses a method for measuring the movement of the main hook of a large lifting ship, which includes obtaining the three-dimensional point cloud of four main hooks 4 based on four lidar sensors 9; obtaining the three-dimensional front view of the point cloud of the four main hooks 4 based on the three-dimensional point cloud; obtaining the three-dimensional coordinates of the movement of the main hook based on the three-dimensional front view of the point cloud and the FVNet algorithm of the target detection framework; and reconstructing and visualizing the movement field of the lifting hook based on the three-dimensional coordinates of the movement of the main hook.

[0053] Specifically, the method for measuring the movement of the main hook of a large lifting ship disclosed in the present invention includes:

[0054] Correction of the absolute movement of the main hook:

[0055] Constructing a main hook target detection algorithm using a deep learning neural network method based on the three-dimensional point cloud generated by the lidar sensor to realize the monitoring of the three-dimensional movement of the main hook.

[0056] The monitoring of the main hook movement is based on the point cloud 3D front view generation and target detection framework FVNet algorithm implementation (it should be pointed out that the "point cloud 3D front view generation and target detection framework FVNet algorithm implementation" recorded in the present invention belongs to the prior art, and the specific reference can be made to the paper FVNet: 3D Front-View Proposal Generation for Real-Time Object Detection from Point Clouds. The creativity of the present invention lies in applying the above method to the specific scenario of large crane ship main hook measurement). The above algorithm includes two stages: the generation of the front view proposal and the estimation of the main hook 3D bounding box parameters. First, the 3D point cloud is projected onto the cylinder to generate a front view feature map that retains rich information. Then a region proposal network is introduced to predict the 3D region proposal from the generated map, and further extract the main hook object of interest from the entire point cloud. Finally, the point features are extracted from the extracted target points, and the final main hook 3D bounding box parameters are regressed in the standard coordinate system. The center point of the main hook 3D bounding box is the 3D coordinate of the main hook movement.

[0057] Since the hull in the water will inevitably be affected by the combined effects of wind, waves and currents, and the laser ranging radar is fixed on the crane arm, it will move along with the hull. During the lifting operation, the absolute coordinate position of the hook is required to match the construction position.

[0058] First, establish the earth coordinate system O-XYZ and the body coordinate system O'-xyz for describing the point coordinates. The earth coordinate system is fixed to the earth, and the origin of the coordinates is the center of gravity of the floating body. The body coordinate system is fixed to the laser radar, and its origin of the coordinates is the center of the radar O'. The x-axis points from the stern to the bow, the y-axis points from the port side to the starboard side, and the z-axis points vertically from the bottom of the radar to the top. Then, the laser radar with an integrated inertial navigation module is installed on the platform, and the radar coverage area is directed to the main hook and the hanging object.

[0059] The laser radar emits a cluster of pulsed lasers at a certain pulse frequency to form a conical measurement area covering the entire domain. Based on the laser ranging principle, the coordinates P0i (x, y, z, t) of each laser reflection point on the wave surface in the body coordinate system are calculated. All reflection points form the main hook coordinate set {P0i (x, y, z, t)}. At the same time, the six-degree-of-freedom motion of the radar relative to the earth coordinate system is synchronously measured by the inertial navigation module integrated on the laser radar. And the coordinate transformation matrix Ni(t) is obtained from the six-degree-of-freedom motion:

[0060]

[0061] Then, in the main hook motion data processing module, the coordinate transformation algorithm is used to transform the main hook coordinate set from the body-fixed coordinate P0i(x, y, z, t) to the earth coordinate Pei(x, y, z, t):

[0062] {Pei} = {Ni(t)}{P0i}

[0063] Thus, based on the lidar and the data processing module, the acquisition of three-dimensional main hook data in the earth coordinate system is completed. Finally, the data processing module sends the acquired three-dimensional main hook coordinate set {Pei} to the central processing computer through wireless or wired data transmission for the reconstruction and visualization of the hook motion field.

[0064] Lidar measurement and data transmission:

[0065] The main console or the sub-console can control simultaneously and generate real-time observation results. When there is no object being lifted, it is the empty hook condition, and when there is an object being lifted, it is the loaded hook condition.

[0066] Empty hook condition

[0067] The main console or the sub-console sends a measurement start signal;

[0068] The lidar receives the signal from the main console or the sub-console and starts the laser emission work;

[0069] The lidar emits lasers covering the entire designed range horizontally and vertically;

[0070] The lidar receives the laser reflected by the main hook and processes and analyzes the reflected signal;

[0071] The lidar converts the collected reflected signal into the position signals of the empty hook in the horizontal and vertical directions;

[0072] The lidar transmits the position signals of the empty hook back to the main console and the sub-console;

[0073] The main console and the sub-console display the position parameters of the empty hook, and process the signal into a three-dimensional model and display the current state in real time on the panels of the main console and the sub-console.

[0074] Precisely observe the real-time motion state of the 6 degrees of freedom of the main hook, providing intelligent auxiliary decision-making for the main hook to judge the construction operation window period and predict dangerous situations.

[0075] The intelligent auxiliary decision-making alarms when the lidar monitors that the angle between the swing of the empty hook and the vertical axis exceeds 15°, and issues alarm messages simultaneously on the main console and the sub-console, reminding the operator that the swing amplitude of the main hook is too large and it is necessary to adjust the hull, boom and wire rope length to reduce the swing of the main hook.

[0076] Lifting load condition

[0077] The main console or the secondary console sends a measurement start signal;

[0078] The laser ranging radar receives the signal from the main console or the secondary console and starts the laser emission work;

[0079] The laser ranging radar emits lasers covering the entire designed range within the horizontal and vertical ranges;

[0080] The laser ranging radar receives the laser reflected by the main hook and processes and analyzes the reflected signal;

[0081] The laser ranging radar converts the collected reflected signal into the position signals of the empty hook in the horizontal and vertical directions;

[0082] The laser ranging radar transmits the position signals of the empty hook back to the main console and the secondary console;

[0083] The main console and the secondary console display the position parameters of the empty hook, and process the signal into a three-dimensional model and display the current state in real time on the panels of the main console and the secondary console.

[0084] At the same time, input the three-dimensional parameters of the lifted object and the lifting appliance and the relative positions of the main hook, the lifting appliance and the lifted object into the panel of the main console or the secondary console, and analyze to obtain the three-dimensional real-time state diagram of the lifted object.

[0085] By accurately measuring the real-time motion state of the 6 degrees of freedom of the main hook, calculate the real-time motion state of the 6 degrees of freedom of the lifted load, and provide an intelligent auxiliary decision for the construction operation regarding the lifted load.

[0086] The intelligent auxiliary decision during lifting the load:

[0087] During single boom operation, when the laser ranging radar monitors that the included angle between the overall swing of the two main hooks and the lifted load and the vertical axis exceeds 5°, an alarm is triggered, and alarm messages are sent simultaneously to the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large, and it is necessary to adjust the hull, the boom and the wire rope length to reduce the swing of the main hook, or lower the main hook and the lifted load to a lower position.

[0088] During double boom operation, when the laser ranging radar monitors that the included angle between the overall swing of the four main hooks and the lifted load and the vertical axis exceeds 5°, an alarm is triggered, and alarm messages are sent simultaneously to the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large, and it is necessary to adjust the hull, the boom and the wire rope length to reduce the swing of the main hook, or lower the main hook and the lifted load to a lower position.

[0089] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application 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. Therefore, it should not be construed as a limitation to the present application. Unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0090] It should be noted that in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0091] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A main hook motion measurement system for a large hoisting ship, characterized in that The invention is used to determine whether a main hook on a large crane ship can reach a swing range that allows for lifting operations, and comprises a crane hull (1), wherein a boom (2) is arranged on the crane hull (1), wherein the boom (2) is connected to a main hook (4) via a hoisting cable (3), and is characterized in that the boom (2) comprises two, each boom (2) is provided with two main hooks (4), and the four main hooks (4) are distributed in a rectangular shape, and two laser ranging radars (9) are fixedly connected to the crossbeam of each boom (2), and the centers of the two laser ranging radars (9) on the crossbeam of each boom (2) are aligned with the center of the crossbeam of the boom (2). The angle formed by the line connecting the centers of the two laser rangefinders (9) is 60°, and the two fan-shaped fields of view of the two laser rangefinders (9) on each boom (2) form a butterfly-shaped field of view, and the field of view range of the butterfly-shaped field of view can completely cover the motion space of the main hook (4) under various working conditions; based on the four laser rangefinders (9), the three-dimensional point clouds of the four main hooks (4) are obtained; based on the three-dimensional point clouds, the three-dimensional front views of the point clouds of the four main hooks (4) are obtained; based on the three-dimensional front views of the point clouds and the target detection framework FVNet algorithm, the three-dimensional coordinates of the main hook motion are obtained; based on the three-dimensional coordinates of the main hook motion, the hook motion field is reconstructed and visualized; Main hook absolute motion correction: Based on the three-dimensional point cloud generated by the laser ranging radar, a deep learning neural network method is used to build a main hook target detection algorithm to achieve the monitoring of the three-dimensional movement of the main hook; The monitoring of the main hook movement is based on the point cloud 3D front view generation and target detection framework FVNet algorithm. First, the 3D point cloud is projected onto a cylindrical surface to generate a front view feature map that retains rich information. Then a region proposal network is introduced to predict the 3D region proposal from the generated map, and further extract the main hook object of interest from the entire point cloud. Finally, point features are extracted from the extracted target points, and the final main hook 3D bounding box parameters are regressed in the standard coordinate system. The center point of the main hook 3D bounding box is the 3D coordinate of the main hook movement. Since the hull in the water will inevitably be affected by the combined effects of wind, waves and currents to produce a certain amount of movement, and the laser ranging radar is fixed on the crane boom and will produce a certain amount of movement with the hull, the absolute coordinate position of the hook is required to match the construction position during the lifting operation; First, establish the earth coordinate system O-XYZ and the body coordinate system O'-xyz for describing the point coordinates. The earth coordinate system is fixed to the earth, and the origin of the coordinates is the center of gravity of the floating body. The body coordinate system is fixed to the laser radar, and its origin of the coordinates is the center of the radar O'. The x-axis points from the stern to the bow, the y-axis points from the port side to the starboard side, and the z-axis points vertically from the bottom of the radar to the top. Then, install the laser radar with an integrated inertial navigation module on the platform, and the radar coverage area is directed to the main hook and the hanging object. The lidar emits a cluster of pulsed lasers at a certain pulse frequency to form a conical measurement area covering the entire area. According to the principle of laser ranging, the coordinates P0i(x, y, z, t) of each laser reflection point on the wave surface in the body coordinate system are calculated. All the reflection points form the main hook coordinate set {P0i(x, y, z, t)}. At the same time, the six-degree-of-freedom motion of the lidar relative to the earth coordinate system is synchronously measured through the inertial navigation module integrated on the lidar And the coordinate transformation matrix Ni(t) is obtained from the six-degree-of-freedom motion: Then, in the main hook motion data processing module, the coordinate transformation algorithm is used to transform the main hook coordinate set from the body coordinate P0i (x, y, z, t) to the earth coordinate Pei (x, y, z, t): {Pei}={Ni(t)}{P0i} Thus, based on the lidar and the data processing module, the acquisition of three-dimensional main hook data in the earth coordinate system is completed; finally, the data processing module sends the collected three-dimensional main hook coordinate set {Pei} to the central processing computer through wireless or wired data transmission for the reconstruction and visualization of the hook motion field; Lidar measurement and data transmission: The main console or the secondary console can control simultaneously and generate real-time observation results. When there is no object being lifted, it is the empty hook condition, and when there is an object being lifted, it is the lifting condition.

2. The main hook motion measurement system of the large hoisting ship according to claim 1, characterized in that Two lidar sensors (9) are installed at the crossbeam of each boom 108 m away from the base.

3. The main hook motion measurement system of the large lifting ship according to claim 1, characterized in that On the crossbeam of each boom (2), a bearing platform (10) is connected through a mounting clamp, and two lidar sensors (9) are arranged on the bearing platform (10).

4. The main hook motion measurement system of the large hoisting ship according to claim 1, characterized in that The boom (2) is a fixed boom, and the boom (2) is arranged at the bow working area.

5. The main hook motion measurement system of the large hoisting ship according to claim 1, characterized in that One end of the lifting cable (3) is connected to the lifting cable winch located on the lifting hull (1), and the other end is connected to the main hook (4).

6. The main hook motion measurement system of the large lifting ship according to claim 1, characterized in that, The measurement method of the main hook motion measurement system of the large lifting ship specifically includes the steps that when the four main hooks (4) are in the empty hook condition, S1, the main console or the secondary console sends a measurement start signal; S2, the lidar sensor receives the signal from the main console or the secondary console and starts the laser emission work; S3, the lidar sensor emits lasers covering the entire designed range within the horizontal and vertical ranges; S4, the lidar sensor receives the laser reflected by the main hook and processes and analyzes the reflected signal; S5, the lidar sensor converts the collected reflected signal into the position signal of the empty hook in the horizontal and vertical directions; S6, the lidar sensor transmits the position signal of the empty hook back to the main console and the secondary console; S7, the main console and the secondary console display the position parameters of the empty hook, and process the signal into a three-dimensional model and display the current state in real time on the panels of the main console and the secondary console; S8, accurately observe the real-time motion state of the 6 degrees of freedom of the main hook, and provide intelligent auxiliary decision-making for the main hook for judging the construction operation window period and predicting dangerous situations.

7. The main hook motion measurement system of the large lifting ship according to claim 6, characterized in that The intelligent auxiliary decision-making alarms when the lidar sensor monitors that the angle between the swing of the empty hook and the vertical axis exceeds 15°, and sends alarm messages simultaneously on the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large and the hull, boom and wire rope length need to be adjusted to reduce the swing of the main hook.

8. The main hook motion measurement system of the large lifting ship according to claim 1, characterized in that, The measurement method of the main hook motion measurement system of the large lifting ship specifically includes the steps that when the four main hooks (4) are in the lifting condition, S1, the main console or the secondary console sends a measurement start signal; S2, the lidar sensor receives the signal from the main console or the secondary console and starts the laser emission work; S3, the lidar sensor emits lasers covering the entire designed range within the horizontal and vertical ranges; S4, the lidar sensor receives the laser reflected by the main hook and processes and analyzes the reflected signal; S5, the lidar sensor converts the collected reflected signal into the position signal of the empty hook in the horizontal and vertical directions; S6, the lidar sensor transmits the position signal of the empty hook back to the main console and the secondary console; S7. The main console and the secondary console display the position parameters of the empty hook, process the signals into a 3D model, and display the current status in real time on the panels of the main console and the secondary console. At the same time, input the 3D parameters of the lifted object and the lifting gear and the relative positions of the main hook, the lifting gear and the lifted object into the panel of the main console or the secondary console, and analyze to obtain the 3D real-time status diagram of the lifted object. S8. By accurately measuring the real-time motion state of the 6 degrees of freedom of the main hook, calculate the real-time motion state of the 6 degrees of freedom of the lifted object, and provide intelligent auxiliary decision-making for the lifting operation.

9. The main hook motion measurement system of the large hoisting ship according to claim 8, characterized in that, Intelligent auxiliary decision-making during lifting: During single-boom operation, when the laser ranging radar monitors that the overall swing of the two main hooks and the lifted object forms an angle with the vertical axis exceeding 5°, an alarm is triggered, and alarm messages are sent simultaneously on the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large and that the hull, boom and wire rope length need to be adjusted to reduce the swing of the main hook, or the main hook and the lifted object need to be lowered to a lower position. During double-boom operation, when the laser ranging radar monitors that the overall swing of the four main hooks and the lifted object forms an angle with the vertical axis exceeding 5°, an alarm is triggered, and alarm messages are sent simultaneously on the main console and the secondary console, reminding the operator that the swing amplitude of the main hook is too large and that the hull, boom and wire rope length need to be adjusted to reduce the swing of the main hook, or the main hook and the lifted object need to be lowered to a lower position.

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