Visual measurement and control method and system for perpendicularity of prefabricated part

Abstract

The invention discloses a visual measurement and control method and system for perpendicularity of a prefabricated part, and belongs to the technical field of engineering measurement. The method comprises the following steps: arranging a laser plumb aligner at a ground reference point around a component pedestal to form a vertical laser reference line; a telescopic vision measurement unit is installed at the corresponding position of the upper portion of the component template and comprises a laser target, an image acquisition module, a driving mechanism, a distance measurement module and a controller, and the controller calculates the target telescopic distance according to preset parameters and controls the driving mechanism to stretch out in place based on feedback of the distance measurement module in a closed-loop mode; the image acquisition module acquires a light spot image on the laser target; the controller processes the image to determine the deviation value of the light spot relative to the center of the target, calculates the real-time perpendicularity in combination with the height of the component, and finally synthesizes the multi-point result. According to the invention, automatic, high-precision and high-efficiency verticality measurement can be realized, the real-time process control capability is realized, and the construction quality and efficiency of the prefabricated part are obviously improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering measurement, and in particular relates to a method and system for visually measuring and controlling the verticality of prefabricated components. Background Art

[0002] With the development of infrastructure construction, such as bridges, prefabrication and assembly technology has gained widespread application. For example, in large bridge construction, such as the Hangzhou Bay Cross-sea Railway Bridge, piers are prefabricated and then hoisted on-site. The prefabricated pier segments can reach heights of up to 16 meters, making them exceptionally tall and large components. For these components, controlling verticality during installation or prefabrication is crucial, directly impacting the safety, appearance, and quality of the structure.

[0003] At present, total stations are often used for verticality measurement in engineering practice. However, when using total stations to measure the verticality of tall prefabricated piers at prefabrication sites or installation sites, there are many problems: (1) Limited installation of measuring stations and safety hazards: Prefabrication sites are usually densely populated with pedestals and often involve large construction machinery. It is difficult to choose the installation location of the total station, and it is difficult to find an ideal and safe measuring station with line of sight. (2) Poor measurement conditions: Due to site space limitations, when measuring tall piers, the measurement distance is often short, resulting in a large vertical angle (elevation angle), which exceeds the instrument's optimal working range and affects accuracy. In extreme cases, for super-high piers or densely arranged sites, line of sight may be lost. (3) Low efficiency and high resource investment: Total station measurement relies on manual operation, resulting in low measurement efficiency. To ensure accuracy, it is usually necessary to set up observation stations in multiple directions (such as the four main directions) of the component for observation, which increases measurement time and manpower and equipment investment; (3) Lack of process control capabilities: Total station measurement is usually carried out after the template installation is basically completed, making it difficult to conduct real-time verticality monitoring during the template assembly and adjustment process. This means that deviations cannot be discovered and corrected in a timely manner through process control, increasing the risk of rework and making it difficult to ensure the final installation accuracy. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a method and system for visual measurement and control of the verticality of prefabricated components in order to address the problems of limited measurement, low efficiency, low precision, and inability to perform real-time process control in the prior art.

[0005] Technical solution: The method for visually measuring and controlling the verticality of prefabricated components of the present invention comprises:

[0006] Step 1: symmetrically set a number of ground reference points along a predetermined axis around a pedestal for placing the prefabricated component to be tested, and set a laser plumb line at each of the ground reference points, the laser plumb line projecting upward to form a vertical laser reference line;

[0007] Step 2: Install a telescopic vision measurement unit on the upper portion of the template of the prefabricated component at a predetermined position corresponding to the ground reference point, the telescopic vision measurement unit comprising: a laser target for receiving the vertical laser reference line, an image acquisition module for acquiring an image on the laser target, a driving mechanism for driving the laser target and the image acquisition module to extend and retract in a predetermined direction, a distance measurement module for measuring the extension and retraction distance, and a controller for control and processing;

[0008] Step 3: Calculating a target telescopic distance of the telescopic vision measurement unit based on preset geometric parameters of the prefabricated component and a preset spatial position relationship between the ground reference point and the prefabricated component;

[0009] Step 4: The controller controls the driving mechanism to dynamically adjust the movement of the driving mechanism according to the real-time feedback signal of the distance measurement module until the telescopic vision measurement unit is extended to the target telescopic distance;

[0010] Step 5: The image acquisition module acquires a spot image formed by projecting the vertical laser reference line onto the laser target;

[0011] Step 6: The controller processes the light spot image to determine a deviation value of the light spot center relative to a predetermined center point of the laser target;

[0012] Step 7: Calculate the verticality of the prefabricated component in the direction corresponding to the ground reference point based on the deviation value and the preset height parameter of the prefabricated component;

[0013] Step 8: Based on several verticality calculation results, the comprehensive verticality of the prefabricated component is obtained.

[0014] To further improve the above technical solution, in step 2, the image acquisition module includes an industrial camera, a reflector for reflecting the laser target image to the industrial camera, and a magnetic fill light; the driving mechanism is an electric push rod; and the laser target is a light-transmitting plate with a preset grid pattern.

[0015] Furthermore, the telescopic vision measurement unit further comprises: an inner square tube and an outer square tube; a slide rail is provided on the outer side of the outer wall or top of the inner square tube, the outer square tube is sleeved on the outside of the inner square tube, and a slider is provided on the inner side of the inner wall or top of the outer square tube for slidingly cooperating with the slide rail; the electric push rod is fixedly mounted on the inner square tube, and the movable telescopic end of the electric push rod is connected to the bottom of the outer square tube, and is used to drive the outer square tube to telescope relative to the inner square tube along the guide direction of the slide rail and the slider, so that the laser target extends or retracts along a predetermined direction;

[0016] The electric push rod, industrial camera, ranging module, controller and power supply assembly are all installed in the inner square tube; the laser target, reflector and magnetic fill light are all installed at the end of the outer square tube, and are located at the end of the outer square tube away from the inner square tube.

[0017] Furthermore, the prefabricated component includes a plurality of segments with different cross-sectional sizes; the preset geometric parameters correspond to the geometric parameters of the prefabricated component segment currently being measured, and the calculated target telescopic distance varies with the geometric parameters of different segments.

[0018] Furthermore, the processing of the light spot image in step 6 includes: identifying the light spot and determining the center coordinates of the light spot by an image recognition algorithm, and calculating the longitudinal deviation between the center coordinates and the predetermined center point of the laser target. and lateral deviation ; The calculation of the verticality in step seven includes: calculating the vertical verticality respectively, and its value is , and the horizontal verticality, whose value is , where H is the preset height parameter.

[0019] Furthermore, the method further includes the steps of establishing a communication connection with the controller through the client, for inputting the preset geometric parameters and the preset spatial position relationship, triggering the execution of the measurement and control method, and receiving and displaying the verticality calculation result.

[0020] Furthermore, the ground reference point is a forced centering pier.

[0021] Accordingly, the present invention also provides a prefabricated component verticality visual measurement and control system for implementing the aforementioned method, comprising:

[0022] A laser plummet is provided corresponding to the ground reference point and is used to project upward to form a vertical laser reference line;

[0023] a telescopic visual measurement unit mounted on the prefabricated component formwork at a predetermined position corresponding to the ground reference point;

[0024] The telescopic visual measurement unit includes: a laser target for receiving the vertical laser reference line, an image acquisition module for acquiring an image of the laser target, a driving mechanism for driving the laser target and the image acquisition module to extend and retract along a predetermined direction, a distance measuring module for measuring the telescopic distance, and a controller;

[0025] The controller is configured to: calculate a target telescopic distance of the telescopic vision measurement unit based on preset geometric parameters of the prefabricated component and a preset spatial positional relationship between the ground reference point and the prefabricated component; control the drive mechanism, according to a real-time feedback signal from the distance measurement module, and dynamically adjust a control instruction to the drive mechanism based on the feedback signal until the telescopic distance reaches the target telescopic distance; control the image acquisition module to acquire a spot image formed by the vertical laser reference line projected onto the laser target; process the spot image to determine a deviation value of the spot center relative to a predetermined center point of the laser target; and calculate the verticality of the prefabricated component at the measuring point based on the deviation value and a preset height parameter of the prefabricated component;

[0026] The client is used to establish a communication connection with the controller to input the preset geometric parameters and preset spatial position relationship, trigger the controller to perform measurement and control operations, and receive and display the verticality calculation result.

[0027] Beneficial Effects: Compared with existing technologies, the present invention offers advantages in that it utilizes an automated telescopic measurement unit and a fixed ground reference, eliminating the need for manual station setup, sighting, and reading. The measurement process is automated and can be performed simultaneously at multiple points, significantly improving measurement efficiency and reducing measurement time. The present invention provides real-time measurement and feedback during template installation and adjustment. Operators can adjust the template promptly based on the real-time verticality display (e.g., displayed via the client, with overshoots highlighted in red), achieving process control, effectively avoiding cumulative errors, and ensuring that the final verticality accuracy meets requirements.

[0028] This invention utilizes a stable ground-based laser vertical reference, combined with the high resolution and precise algorithms of visual measurement, to achieve highly accurate deviation measurement and verticality calculation. Closed-loop controlled telescopic positioning also ensures accurate measurement conditions. Furthermore, compared to total stations that require open space, the fixed ground reference and formwork-mounted measuring unit are less susceptible to environmental factors such as confined construction sites, mechanical interference, and line of sight obstructions, enabling reliable operation in complex construction environments.

[0029] The present invention uses a client (such as a mobile phone APP) to input parameters, control tasks, and view results. It has friendly human-computer interaction and simple operation, making it easy for on-site construction personnel to master and use it. It is not only suitable for tall prefabricated piers, but also for components with variable cross-section characteristics. Accurate measurements can be performed by simply entering the parameters of the corresponding segment.

[0030] The present invention reduces the need for surveyors to work at high altitudes or in complex environments, thereby improving safety; at the same time, it reduces the need for expensive total stations and a large number of surveyors, thereby reducing resource investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a distribution diagram of the forced centering piers in the present invention.

[0032] Figure 2 It is a schematic diagram of the position of the telescopic visual measurement unit in the present invention installed on the prefabricated component through the U-shaped slot.

[0033] Figure 3 It is a structural schematic diagram of the telescopic visual measurement unit in the present invention.

[0034] Figure 4 It is a top view of the top structure after the telescopic visual measurement unit is connected to the prefabricated components in the present invention.

[0035] Figure 5 It is a top view of the middle layer structure after the telescopic visual measurement unit is connected to the prefabricated components in the present invention.

[0036] Figure 6 It is a top view of the underlying structure after the telescopic visual measurement unit is connected to the prefabricated component in the present invention.

[0037] Figure 7 It is a structural schematic diagram of the telescopic visual measurement unit of the present invention after being connected to the prefabricated component and before being telescoped.

[0038] Figure 8 It is a schematic structural diagram of the telescopic visual measurement unit after being connected to the prefabricated component and telescoped in the present invention.

[0039] The reference numerals in the figure are: 1. electric push rod; 2. distance measuring module; 3. industrial camera; 4. controller; 5. step-down module; 6. splitter; 7. battery; 8. slide rail; 9. slider; 10. magnetic fill light; 11. reflector; 12. laser target; 13. electric push rod switch; 14. U-shaped slot; 15. fixing screw; 16. prefabricated component side mold; 17. prefabricated component bottom mold; 19. laser plumb line. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0041] Example 1: The prefabricated component verticality visual measurement and control system provided in this embodiment mainly includes several laser plummets 19 set on ground reference points, several sets of telescopic visual measurement units installed on the upper part of the prefabricated component template, and a client for human-computer interaction and control.

[0042] like Figure 1As shown in the figure, around a typical prefabricated pier pedestal, four ground reference points are symmetrically arranged along its longitudinal and transverse axes. The ground reference points use forced centering piers to ensure that the position of the laser plummet is accurate and consistent each time. Figure 1 The direction of the middle arrow is the direction of the major mileage. The left side of the minor mileage of each prefabricated pier pedestal is the starting point of the forced centering pier numbering. They are numbered 1-1, 1-2, 1-3, and 1-4 in a counterclockwise direction. The first value represents the pedestal number, and the second value represents the forced centering pier number. The distance between each forced centering pier and the longitudinal (horizontal) axis is consistent. A laser plumb line is installed on each forced centering pier, and the instrument is adjusted so that it accurately projects a stable vertical laser reference line upward.

[0043] like Figure 2 As shown, a telescopic vision measuring unit is installed on the upper portion of the precast component formwork, corresponding to each ground reference point. The telescopic vision measuring unit is inserted into a specific position on the formwork (the distance from the center of this position to the component's longitudinal / transverse axis is consistent with the distance from the corresponding forced centering pier to that axis) through a U-shaped slot 14 at the bottom and secured with a set screw 15.

[0044] like Figures 3 to 6 As shown, the telescopic vision measurement unit comprises an inner square tube and an outer square tube, with the inner tube housed within the outer tube. A slide rail 8 is fixed to the outer wall or top of the inner tube, while a slider 9 is fixed to the inner wall or bottom of the outer tube. The slider and the slide rail slide together to form a linear guide mechanism.

[0045] The driving mechanism is preferably an electric push rod 1, whose main body is fixedly mounted on the inner square tube. The movable telescopic end of the electric push rod 1 is connected to the bottom of the outer square tube through a pin. By controlling the extension and retraction of the electric push rod, the outer square tube can be driven to extend or retract accurately relative to the inner square tube along the direction of the slide rail.

[0046] like Figure 3 As shown, the components installed inside the inner square tube include: electric push rod 1, ranging module 2, industrial camera 3, controller 4 (such as industrial computer), power supply assembly (including step-down module 5, splitter 6, battery 7), main power switch, charging interface, and electric push rod switch.

[0047] The components installed on the outer square tube (the end away from the inner square tube) include: a laser target 12, a reflector 11, a magnetic fill light 10 and a slider 9.

[0048] The image acquisition module includes an industrial camera 3 and a reflector 11. Mirror 11 is used to reflect the image from the laser target 12 to the industrial camera 3 mounted on the inner square tube. Laser target 12 is a translucent acrylic sheet with a fine, pre-set grid pattern, facilitating subsequent image processing to determine deviations. The ranging module 2 is used to measure the extension distance of the outer square tube relative to the inner square tube in real time. A magnetic fill light 10 is used to illuminate the laser target when light levels are low. The controller 4 is responsible for the calculations, control, and communication of the entire unit.

[0049] Example 2: A measurement and control method using the system provided in Example 1 includes the following steps:

[0050] Complete the installation and setup of the laser plummet and telescopic vision measurement unit;

[0051] Enter the relevant parameters of the precast component to be measured in the client, including: pedestal number N, pier number D, segment type (such as upper section, middle section, lower section), segment geometric parameters (such as transverse width L, longitudinal length W, height H), vertical distance Slong (Short) from the forced centering pier to the longitudinal (transverse) axis of the pedestal, and the allowable verticality tolerance E. Also enter a constant C, which represents the preset distance between the center of the laser target and the inner wall of the component template when the measuring unit is in the working state (extended).

[0052] Connect the client to the controller of the telescopic vision measuring unit, select the corresponding pedestal number, pier number and segment form, and calculate the theoretical extension distance of the electric push rod. ; The calculation method is: the vertical distance from the forced centering pier to the horizontal axis of the pedestal is known to be , the longitudinal length of the precast pier is known , it is known that the distance between the center of the laser target and the inner wall of the pier side mold before the telescopic visual measurement unit works is a constant C, then: ;

[0053] The controller controls the extension of the electric push rod. The extension process is as follows: Figure 7 、 Figure 8 As shown, the principle of elongation control is: the distance measurement module of the telescopic component before working is known to be After the electric push rod extends and drives the outer square tube to slide, the distance measurement module measures the distance ,satisfy ;

[0054] After combining the formulas, the controller controls the distance measurement: .

[0055] Image acquisition: When the telescopic vision measurement unit is extended into place, the vertical laser reference line projected by the laser plumb line passes through the laser target 12 and forms a clear light spot on it with a diameter usually less than 1 mm. The industrial camera 3 captures the laser target 12 and the light spot image on it through the reflector 11. If there is insufficient light, the magnetic fill light 10 will be automatically or manually turned on.

[0056] Image processing and deviation calculation: After receiving the spot image, the controller runs the built-in image recognition algorithm to identify the laser spot in the image and calculate the pixel coordinates of its center point; combined with the pre-calibrated camera parameters and target grid information, the pixel coordinates of the center of the spot are converted into physical deviation values ​​relative to the predetermined center point of the laser target (theoretically, the position where the laser should land) to obtain the longitudinal deviation. and lateral deviation (Unit: mm).

[0057] Verticality calculation: The controller calculates the verticality at the measuring point based on the calculated deviation value and the input component (or segment) height H:

[0058] Vertical verticality ;

[0059] Horizontal verticality ;

[0060] The verticality results are expressed in thousandths (‰).

[0061] Result Display and Feedback: Calculated deviation and verticality results are sent to the client via a communication link, displaying real-time vertical and horizontal verticality values ​​for each measuring point. A threshold can be set; when verticality exceeds the allowable tolerance E, a prominent indicator (such as a red number or an alarm) appears, while when it passes, the indicator turns green. On-site personnel can use the real-time results displayed on the app to guide template adjustments until verticality meets requirements.

[0062] Comprehensive verticality calculation: When the verticality of all measuring points is adjusted to meet the requirements, the average longitudinal verticality value of all (4 in this embodiment) measuring points of the controller or client is used as the final longitudinal verticality result, and the average transverse verticality value of all measuring points is used as the final transverse verticality result.

[0063] Through the above steps, the present invention realizes the automated, high-precision, real-time visual measurement and control of the verticality of prefabricated components. The entire process does not require manual and complex measurement operations, greatly improving efficiency and reliability, and realizing valuable process control.

[0064] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A method for visually measuring and controlling the verticality of prefabricated components, characterized in that: include: Step 1: symmetrically set a number of ground reference points along a predetermined axis around a pedestal for placing the prefabricated component to be tested, and set a laser plumb line at each of the ground reference points, the laser plumb line projecting upward to form a vertical laser reference line; Step 2: Install a telescopic vision measurement unit on the upper portion of the template of the prefabricated component at a predetermined position corresponding to the ground reference point, the telescopic vision measurement unit comprising: a laser target for receiving the vertical laser reference line, an image acquisition module for acquiring an image on the laser target, a driving mechanism for driving the laser target and the image acquisition module to extend and retract in a predetermined direction, a distance measurement module for measuring the extension and retraction distance, and a controller for control and processing; Step 3: Calculating a target telescopic distance of the telescopic vision measurement unit based on preset geometric parameters of the prefabricated component and a preset spatial position relationship between the ground reference point and the prefabricated component; Step 4: The controller controls the driving mechanism to dynamically adjust the movement of the driving mechanism according to the real-time feedback signal of the distance measurement module until the telescopic vision measurement unit is extended to the target telescopic distance; Step 5: The image acquisition module acquires a spot image formed by projecting the vertical laser reference line onto the laser target; Step 6: The controller processes the light spot image and determines a deviation value of the light spot center relative to a predetermined center point of the laser target; Step 7: Calculate the verticality of the prefabricated component in the direction corresponding to the ground reference point based on the deviation value and the preset height parameter of the prefabricated component; Step 8: Based on several verticality calculation results, the comprehensive verticality of the prefabricated component is obtained.

2. The method for visually measuring and controlling the verticality of prefabricated components according to claim 1 is characterized in that: In step 2, the image acquisition module includes an industrial camera, a reflector for reflecting the laser target image to the industrial camera, and a magnetic fill light; the driving mechanism is an electric push rod; and the laser target is a light-transmitting plate with a preset grid pattern.

3. The method for visually measuring and controlling the verticality of prefabricated components according to claim 2, characterized in that: The telescopic vision measurement unit further includes: an inner square tube and an outer square tube; a slide rail is provided on the outer side of the outer wall or top of the inner square tube, the outer square tube is sleeved on the outside of the inner square tube, and a slider is provided on the inner side of the inner wall or top of the outer square tube to slide with the slide rail; the electric push rod is fixedly mounted on the inner square tube, and the movable telescopic end of the electric push rod is connected to the bottom of the outer square tube, and is used to drive the outer square tube to telescope relative to the inner square tube along the guide direction of the slide rail and the slider, so that the laser target extends or retracts along a predetermined direction; The electric push rod, industrial camera, ranging module, controller and power supply assembly are all installed in the inner square tube; the laser target, reflector and magnetic fill light are all installed at the end of the outer square tube, and are located at the end of the outer square tube away from the inner square tube.

4. The method for visually measuring and controlling the verticality of prefabricated components according to claim 1, characterized in that: The prefabricated component includes a plurality of segments with different cross-sectional sizes; the preset geometric parameters correspond to the geometric parameters of the prefabricated component segment currently being measured, and the calculated target telescopic distance varies with the geometric parameters of different segments.

5. The method for visually measuring and controlling the verticality of prefabricated components according to claim 1, characterized in that: The processing of the light spot image in step 6 includes: identifying the light spot and determining the center coordinates of the light spot by an image recognition algorithm, and calculating the longitudinal deviation between the center coordinates and the predetermined center point of the laser target. and lateral deviation ; The calculation of the verticality in step seven includes: calculating the vertical verticality respectively, and its value is , and the horizontal verticality, whose value is , where H is the preset height parameter.

6. The method for visually measuring and controlling the verticality of prefabricated components according to claim 1, characterized in that: The method further includes the steps of establishing a communication connection with the controller through a client, for inputting the preset geometric parameters and the preset spatial position relationship, triggering the execution of the measurement and control method, and receiving and displaying the verticality calculation result.

7. The method for visually measuring and controlling the verticality of prefabricated components according to claim 1, characterized in that: The ground reference point is the forced centering pier.

8. A system for implementing the method for visually measuring and controlling the verticality of a prefabricated component according to claim 1, applied to the template installation or adjustment process of the prefabricated component, wherein the prefabricated component is set on a pedestal, and a plurality of ground reference points are symmetrically arranged around the pedestal along a predetermined axis, characterized in that: include: A laser plummet is provided corresponding to the ground reference point and is used to project upward to form a vertical laser reference line; a telescopic visual measurement unit mounted on the prefabricated component formwork at a predetermined position corresponding to the ground reference point; The telescopic visual measurement unit includes: a laser target for receiving the vertical laser reference line, an image acquisition module for acquiring an image of the laser target, a driving mechanism for driving the laser target and the image acquisition module to extend and retract along a predetermined direction, a distance measuring module for measuring the telescopic distance, and a controller; The controller is configured to: calculate a target telescopic distance of the telescopic vision measurement unit based on preset geometric parameters of the prefabricated component and a preset spatial positional relationship between the ground reference point and the prefabricated component; control the drive mechanism, according to a real-time feedback signal from the distance measurement module, and dynamically adjust a control instruction to the drive mechanism based on the feedback signal until the telescopic distance reaches the target telescopic distance; control the image acquisition module to acquire a spot image formed by the vertical laser reference line projected on the laser target; process the spot image to determine a deviation value of the spot center relative to a predetermined center point of the laser target; and calculate the verticality of the prefabricated component in the direction corresponding to the ground reference point based on the deviation value and a preset height parameter of the prefabricated component; and obtain a comprehensive verticality of the prefabricated component based on a plurality of verticality calculation results; The client is used to establish a communication connection with the controller to input the preset geometric parameters and preset spatial position relationship, trigger the controller to perform measurement and control operations, and receive and display the verticality calculation result.

9. The system according to claim 8, characterized in that The controller is configured to process the light spot image and calculate the verticality, including: identifying the light spot and determining the center coordinates of the light spot through an image recognition algorithm, and calculating the longitudinal deviation between the center coordinates and the predetermined center point of the laser target. and lateral deviation ; Calculate the vertical verticality respectively, and its value is , and the horizontal verticality, whose value is , where H is the preset height parameter.

10. The system according to claim 8, wherein: It also includes a mounting mechanism for fixing the telescopic vision measurement unit to a prefabricated component template, wherein the mounting mechanism includes a U-shaped slot provided at the bottom of the telescopic vision measurement unit and a fixing screw for fastening.

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