A hoisting construction danger alarm method based on AR technology

Abstract

The application discloses a kind of based on AR technology's visual hoisting construction danger alarm method, comprising the following steps: constructing the three-dimensional real scene model of construction site;Beam three-dimensional model is made and imported into three-dimensional real scene model, simulate the hoisting moving path of beam body;After scanning construction site by intelligent mobile terminal, corresponding three-dimensional real scene model is acquired and hoisting moving path is shown;Intelligent mobile terminal for observation is arranged on observation platform;Beam body is hoisted and moved according to hoisting moving path, and intelligent mobile terminal judges whether beam body deviates, overruns or generates excessive amplitude in real time, and if dangerous, alarm is carried out through intelligent mobile terminal in cab.The application has the advantages that: based on AR software on intelligent mobile terminal, simulation hoisting process animation is shown, and hoisting moving path of beam body can be monitored during hoisting process to judge whether there is deviation, overrun or excessive amplitude in real time, and if so, warning is sent out.

Description

Technical Field

[0001] This invention belongs to the field of engineering hoisting and construction technology, specifically relating to a visual hoisting and construction hazard alarm method based on AR technology. Background Technology

[0002] Augmented Reality (AR) technology is a technique that cleverly integrates virtual information with the real world. It widely utilizes multimedia, 3D modeling, real-time tracking and registration, intelligent interaction, and sensing technologies to simulate and apply computer-generated text, images, 3D models, music, videos, and other virtual information to the real world. The two types of information complement each other, thus "enhancing" the real world. Currently, AR technology is mainly used in the gaming and film industries, with limited application in actual industrial production and construction.

[0003] At bridge construction sites, hoisting equipment is needed to lift and erect bridge beams. During this beam erection process, due to the presence of existing structures and various formwork or construction equipment on the construction site, there may be collision hazards, excessive beam swaying amplitude, or beam deviation from the preset path during the lifting process. However, these construction hazards often cannot be detected and warned in time during the construction process.

[0004] Therefore, those skilled in the art urgently need a method that can provide timely warnings of construction hazards during hoisting operations. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a visual hoisting construction hazard alarm method based on AR technology. This construction hazard alarm method is based on AR software on a smart mobile terminal, which displays a simulated hoisting process animation and can monitor the hoisting movement path of the beam during the hoisting process to determine in real time whether there is a danger of deviation, exceeding limits, or excessive amplitude. If so, an early warning is issued.

[0006] The objective of this invention is achieved through the following technical solutions:

[0007] A visual alarm method for hoisting construction based on AR technology, characterized in that the alarm method includes the following steps:

[0008] S1: Set up at least three positioning piles and at least one observation platform within the boundary of the construction site. Use a three-dimensional laser scanning device to perform three-dimensional laser scanning on the existing structures and positioning piles at the construction site to construct the three-dimensional real scene model of the construction site. The positioning piles are set as positioning and identification feature points, and the existing structures are set as clustering feature points, which serve as key elements for query matching of the three-dimensional real scene model.

[0009] S2: Create a 3D model of the hoisting equipment and a 3D model of the beam on the computer; import the 3D model of the hoisting equipment and the 3D model of the beam into the 3D reality model of the construction site; preset and simulate the hoisting movement path of the 3D model of the hoisting equipment to hoist the 3D model of the beam in the 3D reality model of the construction site; the hoisting movement path is divided into a vertical hoisting path and a horizontal movement path;

[0010] The vertical hoisting path is fitted by several vertical position measuring points. Several construction devices with potential collision hazards are distributed on both sides of the vertical hoisting path. The construction devices are set as collision clustering feature points.

[0011] The horizontal movement path is fitted by several horizontal position measuring points, and a supporting beam is set on the horizontal movement path. The supporting beam is set as the hoisting and positioning clustering feature point.

[0012] S3: Before the hoisting operation, the construction personnel stand on the observation platform and use AR software on a smart mobile terminal to scan and detect the construction site from a bird's-eye view. During the scanning and detection process, they find the three positioning and identification feature points and the clustering feature points located on the horizontal plane. Based on the positioning and identification feature points and the clustering feature points as key elements for query matching, they perform query matching on the cloud server of the AR software. The 3D real-scene model that is matched by the query is displayed on the AR software interface of the smart mobile terminal, and a simulated hoisting process animation of the hoisting equipment 3D model hoisting the beam 3D model is displayed. The simulated hoisting process animation includes the hoisting movement path.

[0013] S4: The intelligent mobile terminal is fixedly mounted on the observation platform using a bracket, and the downward shooting angle of the intelligent mobile terminal's camera is associated with the three-dimensional real scene model;

[0014] S5: At the construction site, the beam transport equipment moves the beam to the first hoisting point. Construction workers operate the hoisting equipment according to the hoisting movement path shown in the simulated hoisting process animation.

[0015] At least three sets of laser ranging devices are arranged longitudinally at intervals on the lower surface of the beam, with the centrally located laser ranging device positioned at the center point of the lower surface of the beam. Each set of laser ranging devices monitors the height of the lower surface of the beam from the ground in real time. The centrally located laser ranging device represents the real-time height of the beam, and the difference between the monitoring height of the laser ranging devices on both sides and the monitoring height of the centrally located laser ranging device represents the vertical amplitude of the beam.

[0016] The hoisting equipment is operated to hoist the beam according to the vertical hoisting path. During the hoisting process, it is determined whether the beam moves continuously along the vertical position measuring point, whether the distance between the boundary of the beam and the construction device is within a safe distance, and whether the vertical amplitude of the beam exceeds the threshold. If any deviation or over-limit situation is found, an alarm is notified through the intelligent mobile terminal set in the cab of the hoisting equipment.

[0017] The hoisting equipment is operated to install the beam by moving it horizontally along the horizontal movement path. During the erection of the beam, it is determined whether the beam moves continuously along the horizontal position measuring point. If it is found that the beam does not move continuously along the horizontal position measuring point, an alarm is issued through the intelligent mobile terminal in the operator's cab of the hoisting equipment.

[0018] S6: Repeat step S5 until the hoisting and erection of each beam is completed in sequence.

[0019] The three-dimensional real-scene model in step S1 is stored in the cloud server of the AR software, and the cloud server stores several three-dimensional real-scene models of construction sites.

[0020] In step S3, the overhead shooting angle is the angle between the camera of the smart mobile terminal and the horizontal plane; when querying the matching key elements, each of the three-dimensional real scene models in the cloud server is adjusted to a display viewpoint based on the overhead shooting angle.

[0021] In step S3, the AR software performs a query matching based on the location identification feature points and the clustering feature points as key elements of the query matching. This includes the following steps: based on the clustering feature points of the existing structures, the cloud server is used to query and obtain 3D models of existing structures with the same clustering feature points in different 3D real-world models. Then, the horizontal distance between the clustering feature points and each location identification feature point is used to confirm the corresponding 3D model of the structure. The 3D real-world model in which the 3D model of the structure is located is the query matching result.

[0022] In step S4, associating the overhead shooting angle of the camera of the smart mobile terminal with the three-dimensional real scene model means adjusting the display perspective of the three-dimensional real scene model to be the same as the overhead shooting angle of the camera of the smart mobile terminal.

[0023] In step S5, the intelligent mobile terminal located on the observation platform takes a picture of the beam from above using a camera, converting the movement trajectory of the beam's center point into several trajectory points. These trajectory points are then compared with the preset vertical and horizontal position measurement points in the 3D real-scene model. If three consecutive points of the beam's trajectory points deviate from the vertical position measurement points in the vertical hoisting path, it indicates that the beam has shifted during the vertical hoisting process. Similarly, if three consecutive points of the beam's trajectory points deviate from the horizontal position measurement points in the horizontal movement path, it indicates that the beam has shifted during the horizontal hoisting process.

[0024] In step S5, a first laser rangefinder is installed on each of the two end faces of the beam, and a second laser rangefinder is installed on each of the two ends of the upper surface of the beam. The first laser rangefinder is used to monitor the distance between the two end faces of the beam and the construction device, and the second laser rangefinder is used to monitor the distance between the upper surface of the beam and the construction device.

[0025] In step S5, before the beam is hoisted onto the supporting crossbeam at both ends and before the hoisting of the beam is released, the AR software on the smart mobile terminal identifies the hoisting positioning cluster feature points of the supporting crossbeam and determines whether the ends of the beam are centered on the hoisting positioning cluster feature points. If so, the hoisting of the beam is released and the process proceeds to step S6; otherwise, the beam is hoisted for fine-tuning.

[0026] The advantages of this invention are:

[0027] (1) Based on the AR software on the smart mobile terminal, the corresponding three-dimensional real scene model can be matched from the cloud server through the captured construction site image, and the simulated hoisting process animation of the hoisting equipment model and beam model can be displayed in the three-dimensional real scene model, so that the hoisting equipment operator can clearly understand the requirements and path planning for hoisting construction.

[0028] (2) Multiple sets of laser ranging devices are installed at intervals on the lower surface of the hoisted beam. The vertical amplitude of the entire beam can be monitored through the laser ranging devices, and this parameter is used as the basis for alarm.

[0029] (3) During the beam hoisting process, the AR software on the smart mobile terminal captures the beam hoisting movement path in real time through its camera device. If the actual movement trajectory of the beam deviates from the preset hoisting movement path, an alarm is issued.

[0030] (4) During the beam hoisting process, the distance between the beam and the construction equipment on both sides is monitored in real time by laser rangefinders set on the two ends and the upper surface of the beam to determine whether the beam is within a safe distance from the construction equipment. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the positioning piles, existing structures, and observation platforms distributed at the construction site in this invention.

[0032] Figure 2 This is a schematic diagram of a construction site image captured by AR software within a smart mobile terminal in this invention.

[0033] Figure 3 This is a schematic diagram of the AR software in this invention matching the corresponding 3D real-world model of the construction site and displaying the hoisting movement path animation;

[0034] Figure 4 This is a schematic diagram illustrating the use of hoisting equipment to lift bridge beams onto the construction site in this invention.

[0035] Figure 5 This is a schematic diagram of the laser ranging device arranged on the beam in this invention. Implementation

[0036] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art:

[0037] like Figure 1-5 The markings in the diagram are as follows: 1. Construction site; 2. Positioning pile; 3. Existing structure; 4. Observation platform; 5. Support beam; 6. Construction device; 7. Beam; 8. Lifting equipment; 9. Laser rangefinder; 10. First laser rangefinder; 11. Second laser rangefinder; 12.

[0038] Example: Figure 1 , 2 As shown in Figure 3, this embodiment specifically relates to a visual hoisting construction hazard alarm method based on AR technology. The alarm method mainly includes the following steps:

[0039] (S1) As Figure 1As shown, at least three positioning piles 2 are set within the boundary of construction site 1. Existing structures 3 are located within the boundary. An observation platform 4 that can overlook the entire construction site 1 is set outside the boundary. Within construction site 1, the existing structures 3, positioning piles 2 and other objects are scanned using a 3D laser scanning device to construct a corresponding 3D real-scene model of construction site 1. The 3D real-scene model is uploaded and stored in the cloud server of AR software. The cloud server stores 3D real-scene models of different construction sites. In later use, users can scan the construction site with AR software to query and match the corresponding 3D real-scene model.

[0040] In this process, positioning stake 2 is set as the positioning identification feature point, and existing structure 3 is set as the clustering feature point, serving as the key elements for querying and matching the 3D real scene model. During the query matching process, a planar coordinate system can be constructed through the positioning identification feature points corresponding to the three positioning stakes 2, and the relative positional relationship between the existing structure 3 and each positioning stake 2 can be transformed into the position in the planar coordinate system. Therefore, the corresponding 3D real scene model can be accurately identified and matched during the query matching process.

[0041] (S2) Construction site 1 is a bridge erection site, which requires the use of hoisting equipment 9 to hoist the beam 8 onto the bridge for installation. Therefore, based on the engineering conditions of construction site 1, a three-dimensional model of hoisting equipment 9 and a three-dimensional model of beam 8 are created on a professional modeling software on a computer. The created three-dimensional models of hoisting equipment and beam are then imported into the corresponding three-dimensional real-world model of construction site 1. In addition, the hoisting movement path of the hoisting equipment three-dimensional model to hoist the beam three-dimensional model is preset and simulated in the three-dimensional real-world model. When preset and simulated, the possibility of potential collisions needs to be considered. Therefore, the hoisting movement path needs to be designed according to the placement of the construction device 7 at construction site 1.

[0042] The hoisting and moving path of beam 8 is divided into two stages: the vertical hoisting path and the horizontal moving path.

[0043] For the vertical hoisting path, the path is divided into several vertical position measuring points. The vertical hoisting path is obtained by fitting these continuously spaced vertical position measuring points. Several construction devices 7 with potential collision hazards are distributed on both sides of the vertical hoisting path. The construction devices 7 are set as collision clustering feature points. During the hoisting process, the boundary of the beam 8 and the boundary of the construction device 7 need to be kept within a safe distance.

[0044] For the horizontal movement path, the path is divided into several horizontal position measuring points. The horizontal movement path can be fitted by these continuously spaced horizontal position measuring points. The upper end of the pier column is the supporting beam 6. The two ends of the beam 8 are finally erected on the supporting beam 6. The final horizontal position measuring point on the horizontal movement path is the erection position of the beam 8. Therefore, the supporting beam 6 is set as the hoisting and positioning cluster feature point to facilitate the verification of the erection position of the beam 8 in the later stage.

[0045] (S3) such as Figure 1 , 2 As shown in Figure 3, before the hoisting operation, the construction personnel stand on the observation platform 4 and use the AR software on the smart mobile terminal to scan and detect the construction site 1 from a top-down angle. During the scanning and detection process, they search for three positioning identification feature points (i.e., positioning piles 2) and clustering feature points (i.e., existing structures 3) located on the horizontal plane. Based on the positioning identification feature points and clustering feature points as key elements for query matching, they perform query matching on the cloud server of the AR software. The 3D real scene model obtained by the query matching is displayed on the AR software interface of the smart mobile terminal, and the simulated hoisting process animation of the hoisting equipment 3D model hoisting the beam 3D model is displayed. The simulated hoisting process animation includes the hoisting movement path of the beam 8.

[0046] The so-called overhead angle is the angle between the camera of the smart mobile terminal and the horizontal plane. When querying the matching key elements, the three-dimensional real scene models in the cloud server are adjusted to display perspectives based on the same overhead angle. By adjusting the overhead angle to be the same, the image of construction site 1 captured by the smart mobile terminal can be directly compared and queried with the three-dimensional real scene models in the cloud server.

[0047] The query matching process in the cloud server of the AR software, based on location identification feature points and clustering feature points as key elements, includes the following steps: Querying the cloud server based on the clustering feature points of existing structures to obtain 3D models of existing structures with the same clustering feature points in different 3D real-world models; then confirming the corresponding 3D model of the structure based on the horizontal distance between the clustering feature points and each location identification feature point; the 3D real-world model where the 3D model of the structure is located is the query matching result.

[0048] (S4) such as Figure 1 As shown, the smart mobile terminal is fixedly mounted on the observation platform 4 using the bracket 5, and the downward shooting angle of the smart mobile terminal's camera is associated with the three-dimensional real scene model. That is, the display perspective of the three-dimensional real scene model is adjusted to be the same as the downward shooting angle of the smart mobile terminal's camera.

[0049] (S5) At the construction site, the beam transport equipment moves the beam 8 to the first hoisting point at construction site 1. The construction personnel operate the hoisting equipment according to the hoisting movement path shown in the simulated hoisting process animation, as follows:

[0050] (S5.1) Vertical hoisting path:

[0051] During the vertical hoisting process, the system determines whether beam 8 is continuously hoisted and moved along the vertical position measuring points, whether the distance between the boundary of beam 8 and the construction device 7 is within a safe distance, and whether the vertical amplitude of beam 8 exceeds a threshold. If any deviation or over-limit situation is detected, an alarm is triggered via the intelligent mobile terminal installed in the cab of the hoisting equipment 9, so that the operator can immediately stop the operation or make targeted corrections. It should be noted that an intelligent mobile terminal is installed in the cab of the hoisting equipment 9. The AR software in the intelligent mobile terminal is activated, and the monitoring screen from the intelligent mobile terminal on the observation platform 4 is displayed in real time. Therefore, the operator can know the hoisting status of beam 8 in real time, and the AR software will also activate the alarm operation at any time in dangerous situations.

[0052] like Figure 1 , 4 As shown in Figure 5, at least three sets of laser ranging devices 10 are arranged longitudinally on the lower surface of the beam 8. The set of laser ranging devices 10 arranged in the middle is located at the center point of the lower surface of the beam, while the other two sets of laser ranging devices 10 are arranged near the two ends of the lower surface of the beam 8. Each set of laser ranging devices 10 monitors the distance between its location and the ground in real time. The difference between the monitoring height of the laser ranging devices 10 arranged at both ends and the monitoring height of the laser ranging device 10 arranged in the middle represents the vertical amplitude of the beam 10.

[0053] like Figure 1 , 4 As shown in Figure 5, the intelligent mobile terminal located on the observation platform 4 takes a picture of the beam 8 from above using a camera, and converts the movement trajectory of the center point of the beam 8 into several trajectory points. The trajectory points are then compared with the preset vertical position measuring points in the three-dimensional real scene model. If three consecutive points of the trajectory points of the beam 8 deviate from the vertical position measuring points in the vertical hoisting path, it indicates that the beam 8 has deviated during the vertical hoisting process. It should be noted that there is a tolerance distance of 10cm between the trajectory points and the vertical position measuring points, that is, deviations within 10cm will not be judged as deviations.

[0054] like Figure 1 , 4As shown in Figure 5, during the hoisting of the beam 8, the construction device 7 may cause a collision. Therefore, a first laser rangefinder 11 is installed on each of the two end faces of the beam 8, and a second laser rangefinder 12 is installed on each of the two ends of the upper surface of the beam 8. The first laser rangefinder 11 monitors the distance between the two end faces of the beam 8 and the construction device 7, and the second laser rangefinder monitors the distance between the upper surface of the beam 8 and the construction device 7. It is necessary to ensure that the distance is within a safe distance. If the distance is less than the preset safe distance threshold, a collision hazard may occur, and an alarm will be triggered through the intelligent mobile terminal installed in the cab to remind the driver.

[0055] (S5.2) Horizontal hoisting path

[0056] In the horizontal hoisting path, it is determined whether the beam 8 is continuously hoisted and moved along the horizontal position measuring point, whether the distance between the boundary of the beam 8 and the construction device 7 is within the safe distance, and whether the vertical amplitude of the beam 8 exceeds the threshold. If any deviation or over-limit situation is found, an alarm is notified through the intelligent mobile terminal set in the cab of the hoisting equipment 9 so that the driver can stop the operation immediately or make targeted corrections. The specific judgment method is the same as in step S5.1.

[0057] It should be noted that the last step in the horizontal hoisting path is to determine the erection position of both ends of the beam 8 on the supporting beam 6. Before the beam 8 is hoisted onto the supporting beam 6, the AR software on the smart mobile terminal on the high platform 4 identifies the hoisting and positioning cluster feature points of the supporting beam and determines whether the ends of the beam 8 are erected in the preset position on the hoisting and positioning cluster feature points. If so, the hoisting of the beam 8 is released and the process proceeds to step S6; otherwise, the beam 8 is lifted for fine-tuning.

[0058] (S6) Repeat step S5 until the hoisting and erection of each beam is completed in sequence.

[0059] The beneficial effects of this embodiment are as follows:

[0060] (1) Based on the AR software on the smart mobile terminal, the corresponding three-dimensional real scene model can be matched from the cloud server through the captured construction site image, and the simulated hoisting process animation of the hoisting equipment model and beam model can be displayed in the three-dimensional real scene model, so that the hoisting equipment operator can clearly understand the requirements and path planning for hoisting construction.

[0061] (2) Multiple sets of laser ranging devices are installed at intervals on the lower surface of the hoisted beam. The vertical amplitude of the entire beam can be monitored through the laser ranging devices, and this parameter is used as the basis for alarm.

[0062] (3) During the beam hoisting process, the AR software on the smart mobile terminal captures the beam hoisting movement path in real time through its camera device. If the actual movement trajectory of the beam deviates from the preset hoisting movement path, an alarm is issued.

[0063] (4) During the beam hoisting process, the distance between the beam and the construction equipment on both sides is monitored in real time by laser rangefinders set on the two ends and the upper surface of the beam to determine whether the beam is within a safe distance from the construction equipment.

Claims

1. A visual alarm method for hoisting construction hazards based on AR technology, characterized in that... The alarm method includes the following steps: S1: Set up at least three positioning piles and at least one observation platform within the boundary of the construction site. Use a three-dimensional laser scanning device to perform three-dimensional laser scanning on the existing structures and positioning piles at the construction site to construct the three-dimensional real scene model of the construction site. The positioning piles are set as positioning and identification feature points, and the existing structures are set as clustering feature points, which serve as key elements for query matching of the three-dimensional real scene model. S2: Create a 3D model of the hoisting equipment and a 3D model of the beam on the computer; import the 3D model of the hoisting equipment and the 3D model of the beam into the 3D reality model of the construction site; preset and simulate the hoisting movement path of the 3D model of the hoisting equipment to hoist the 3D model of the beam in the 3D reality model of the construction site; the hoisting movement path is divided into a vertical hoisting path and a horizontal movement path; The vertical hoisting path is fitted by several vertical position measuring points. Several construction devices with potential collision hazards are distributed on both sides of the vertical hoisting path. The construction devices are set as collision clustering feature points. The horizontal movement path is fitted by several horizontal position measuring points, and a supporting beam is set on the horizontal movement path. The supporting beam is set as the hoisting and positioning clustering feature point. S3: Before the hoisting operation, the construction personnel stand on the observation platform and use AR software on a smart mobile terminal to scan and detect the construction site from a bird's-eye view. During the scanning and detection process, they find the three positioning and identification feature points and the clustering feature points located on the horizontal plane. Based on the positioning and identification feature points and the clustering feature points as key elements for query matching, they perform query matching on the cloud server of the AR software. The 3D real-scene model that is matched by the query is displayed on the AR software interface of the smart mobile terminal, and a simulated hoisting process animation of the hoisting equipment 3D model hoisting the beam 3D model is displayed. The simulated hoisting process animation includes the hoisting movement path. S4: The intelligent mobile terminal is fixedly mounted on the observation platform using a bracket, and the downward shooting angle of the intelligent mobile terminal's camera is associated with the three-dimensional real scene model; S5: At the construction site, the beam transport equipment moves the beam to the first hoisting point. Construction workers operate the hoisting equipment according to the hoisting movement path shown in the simulated hoisting process animation. At least three sets of laser ranging devices are arranged longitudinally at intervals on the lower surface of the beam, with the centrally located laser ranging device positioned at the center point of the lower surface of the beam. Each set of laser ranging devices monitors the height of the lower surface of the beam from the ground in real time. The centrally located laser ranging device represents the real-time height of the beam, and the difference between the monitoring height of the laser ranging devices on both sides and the monitoring height of the centrally located laser ranging device represents the vertical amplitude of the beam. The hoisting equipment is operated to hoist the beam according to the vertical hoisting path. During the hoisting process, it is determined whether the beam moves continuously along the vertical position measuring point, whether the distance between the boundary of the beam and the construction device is within a safe distance, and whether the vertical amplitude of the beam exceeds the threshold. If any deviation or over-limit situation is found, an alarm is notified through the intelligent mobile terminal set in the cab of the hoisting equipment. The hoisting equipment is operated to install the beam by moving it horizontally along the horizontal movement path. During the erection of the beam, it is determined whether the beam moves continuously along the horizontal position measuring point. If it is found that the beam does not move continuously along the horizontal position measuring point, an alarm is issued through the intelligent mobile terminal in the operator's cab of the hoisting equipment. S6: Repeat step S5 until the hoisting and erection of each beam is completed in sequence.

2. The AR-based visual hoisting construction hazard alarm method according to claim 1, characterized in that... The three-dimensional real-scene model in step S1 is stored in the cloud server of the AR software, and the cloud server stores several three-dimensional real-scene models of construction sites.

3. The AR-based visual hoisting construction hazard alarm method according to claim 1, characterized in that... In step S3, the overhead shooting angle is the angle between the camera of the smart mobile terminal and the horizontal plane; when querying the matching key elements, each of the three-dimensional real scene models in the cloud server is adjusted to a display viewpoint based on the overhead shooting angle.

4. The AR-based visual hoisting construction hazard alarm method according to claim 3, characterized in that... In step S3, the AR software performs a query matching based on the location identification feature points and the clustering feature points as key elements of the query matching. This includes the following steps: based on the clustering feature points of the existing structures, the cloud server is used to query and obtain 3D models of existing structures with the same clustering feature points in different 3D real-world models. Then, the horizontal distance between the clustering feature points and each location identification feature point is used to confirm the corresponding 3D model of the structure. The 3D real-world model in which the 3D model of the structure is located is the query matching result.

5. The AR-based visual hoisting construction hazard alarm method according to claim 1, characterized in that... In step S4, associating the overhead shooting angle of the camera of the smart mobile terminal with the three-dimensional real scene model means adjusting the display perspective of the three-dimensional real scene model to be the same as the overhead shooting angle of the camera of the smart mobile terminal.

6. The AR-based visual hoisting construction hazard alarm method according to claim 5, characterized in that... In step S5, the intelligent mobile terminal located on the observation platform takes a picture of the beam from above using a camera, converting the movement trajectory of the beam's center point into several trajectory points. These trajectory points are then compared with the preset vertical and horizontal position measurement points in the 3D real-scene model. If three consecutive points of the beam's trajectory points deviate from the vertical position measurement points in the vertical hoisting path, it indicates that the beam has shifted during the vertical hoisting process. Similarly, if three consecutive points of the beam's trajectory points deviate from the horizontal position measurement points in the horizontal movement path, it indicates that the beam has shifted during the horizontal hoisting process.

7. A visual hoisting construction hazard alarm method based on AR technology according to claim 6, characterized in that... In step S5, a first laser rangefinder is installed on each of the two end faces of the beam, and a second laser rangefinder is installed on each of the two ends of the upper surface of the beam. The first laser rangefinder is used to monitor the distance between the two end faces of the beam and the construction device, and the second laser rangefinder is used to monitor the distance between the upper surface of the beam and the construction device.

8. A visual hoisting construction hazard alarm method based on AR technology according to claim 7, characterized in that... In step S5, before the beam is hoisted onto the supporting crossbeam at both ends and before the hoisting of the beam is released, the AR software on the smart mobile terminal identifies the hoisting positioning cluster feature points of the supporting crossbeam and determines whether the ends of the beam are centered on the hoisting positioning cluster feature points. If so, the hoisting of the beam is released and the process proceeds to step S6; otherwise, the beam is hoisted for fine-tuning.

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