An intelligent tightening system and method based on projection guidance and machine vision

Abstract

The application discloses an intelligent tightening system and method based on projection guidance and machine vision, and belongs to the technical field of intelligent manufacturing and assembly process, which comprises a data processing module, a projection guidance module and a machine vision module.The data processing module is used for constructing a process database, generating a tightening process file of a workpiece to be tightened according to the process database, issuing data related to projection guidance and tightening execution operation according to the tightening process file, and processing and storing projection images, visual images and tightening data.The projection guidance module is used for guiding workpiece tightening operation and abnormity operation alarm by using the projection images.The machine vision module is used for collecting visual images of the workpiece to be tightened, detecting and matching the workpiece to be tightened, and identifying the tightening hole position of the workpiece to be tightened and the position of a tightening execution module.The tightening execution module is used for executing the tightening operation and collecting tightening data.The application can realize the visualization of tightening points, accurate guidance and intelligent control of tightening operation.

Description

Technical Field

[0001] This invention relates to an intelligent tightening system and method based on projection guidance and machine vision, belonging to the field of intelligent manufacturing and assembly technology. Background Technology

[0002] In modern manufacturing, bolted connections, as a reliable fastening method, are widely used in various fields such as engineering machinery, aerospace, shipbuilding, and automobile manufacturing. The reliability and accuracy of bolted connections directly affect the safety and performance of the entire machine, especially in the assembly of large structural components and complex parts. To ensure connection quality, such assemblies typically employ cross-symmetrical or step-by-step tightening strategies. However, with the increase in the size of structural components and the number of bolts, traditional manual tightening operations have gradually revealed some problems: such as difficulty in bolt positioning, cumbersome tightening parameter settings, and complex operations, leading to frequent occurrences of incorrect tightening, missed tightening, and tightening not in accordance with the process flow. Traditional manual tightening operations not only increase the labor intensity and learning burden of operators but may also pose potential hazards to the assembly quality and safety of the product.

[0003] In recent years, visual recognition technology and digital assembly technology have been gradually applied to the manufacturing field to assist in workpiece positioning, assembly process prompts, and operation verification. However, existing bolt tightening systems lack intelligent guidance and automatic feedback functions. Operators still need to frequently adjust parameters and position bolts during complex assembly processes, resulting in a high dependence on manual operation and failing to completely solve the problems associated with manual tightening. Moreover, existing systems lack effective monitoring and error handling capabilities and still cannot meet the tightening needs of complex workstations and multi-bolt scenarios. Summary of the Invention

[0004] The purpose of this invention is to provide an intelligent tightening system and method based on projection guidance and machine vision. It comprehensively utilizes machine vision, projection transformation calibration, tightening data acquisition and process closed-loop control technologies to achieve visualization and precise guidance of tightening points, as well as intelligent control of tightening operations. This solves the problems of difficult positioning, inconsistent process execution and lack of real-time abnormal prompts in traditional manual assembly, thereby improving the accuracy, consistency and production efficiency of bolt tightening.

[0005] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution:

[0006] In a first aspect, the present invention provides an intelligent tightening system based on projection guidance and machine vision, comprising:

[0007] The data processing module is used to build a process database, generate tightening process files for the workpiece to be tightened based on the process database, issue projection guidance and tightening execution data based on the tightening process files, and also process and store projection images, visual images and tightening data uploaded by other modules.

[0008] The projection guidance module is used to project the tightening hole position and process status information into the surface of the workpiece to be tightened in the form of an image, to guide the tightening operation and provide alarm prompts for abnormal operation.

[0009] The machine vision module is used to acquire visual images of the workpiece to be tightened, detect and match the workpiece to be tightened, and identify the tightening hole positions and the position of the tightening execution module of the workpiece to be tightened.

[0010] The tightening execution module is used to perform tightening operations based on the projected image, visual image, and tightening parameters, and to collect tightening data.

[0011] In conjunction with the first aspect, the process database further includes CAE files of different workpieces, tightening operation sequence, and tightening parameter configuration; the tightening process file includes the tightening hole coordinates of the workpiece to be tightened, the tightening operation sequence, the projection image matching the tightening operation, and the tightening parameters.

[0012] Secondly, the present invention provides a control method for an intelligent tightening system based on projection guidance and machine vision, comprising:

[0013] Alignment of the camera coordinate system, projection coordinate system, and workpiece coordinate system based on the calibration plate and projection reference image;

[0014] The machine vision module is used to acquire a visual image of the workpiece to be tightened, thereby obtaining the workpiece information.

[0015] Tightening process documents are generated based on workpiece information and a pre-built process database;

[0016] According to the tightening process document, the projected images are sequentially projected onto the surface of the workpiece to be tightened and the corresponding tightening parameters are issued. Under the guidance of the projected images and the visual positioning of the industrial camera, the tightening execution module is controlled to perform the tightening operation.

[0017] In conjunction with the second aspect, further, the alignment of the camera coordinate system, projection coordinate system, and workpiece coordinate system based on the calibration plate and the projected reference image includes:

[0018] The calibration plate is fixed at the tooling reference position of the intelligent tightening system. The data processing module processes the calibration plate image acquired by the machine vision module and establishes the mapping relationship between the camera coordinate system and the workpiece coordinate system.

[0019] The projection guidance module projects a preset projection reference image onto the calibration board. The deviation between the theoretical position and the actual position of the projection reference image is compared with the visual image acquired by the machine vision module. The projection transformation matrix from camera coordinates to projection coordinates is calculated by detecting feature points on the calibration board.

[0020] Based on the mapping relationship between the camera coordinate system and the workpiece coordinate system, and the projection transformation matrix from camera coordinates to projection coordinates, the projection coordinate system and the workpiece coordinate system are aligned.

[0021] The calibration board of the tightening execution module is used to collect the position coordinates of the tightening execution module in real time, and the visual images collected by the machine vision module are used to perform tightening positioning and alignment with the workpiece coordinate system.

[0022] In conjunction with the second aspect, the expression for the projection transformation matrix from camera coordinates to projected coordinates is as follows:

[0023] ;

[0024] in, Let H be the coordinates of the i-th feature point in the projected coordinate system, and let H be the projection transformation matrix. Let be the coordinates of the i-th feature point in the camera coordinate system.

[0025] In conjunction with the second aspect, further, the process of acquiring a visual image of the workpiece to be tightened using a machine vision module to obtain workpiece information includes:

[0026] The machine vision module acquires visual images of the workpiece to be tightened, the data processing module processes the visual images, and the workpiece model and its installation posture are determined by label recognition or shape matching to obtain workpiece information.

[0027] If an incorrect workpiece model or abnormal installation posture is detected, an alarm message will be generated.

[0028] In conjunction with the second aspect, further, based on the workpiece information, CAE file, and tightening operation sequence, the data processing module generates a projection image corresponding to each tightening operation step, and associates the projection image with the tightening parameters according to the tightening operation sequence.

[0029] In conjunction with the second aspect, further, according to the tightening process document, the projection images are sequentially projected onto the surface of the workpiece to be tightened and the corresponding tightening parameters are issued. Under the guidance of the projection images and the visual positioning of the industrial camera, the tightening execution module is controlled to perform the tightening operation, including:

[0030] Based on the mapping relationship between the projected coordinates and the workpiece coordinates, the projected image is corrected in position and then projected onto the surface of the workpiece to be tightened.

[0031] The machine vision module acquires the projected image and the visual image of the tightening execution module in real time. Combined with the position coordinates of the tightening execution module, the data processing module determines whether the tightening execution module has entered the projection area and generates a tightening permission signal.

[0032] In response to the tightening permission signal, the tightening execution module is unlocked, the tightening parameters corresponding to the projected image are sent down, and the tightening execution module is controlled to perform the current tightening operation.

[0033] In conjunction with the second aspect, further, the step of using the data processing module to determine whether the tightening execution module has entered the projection area and generating a tightening permission signal includes:

[0034] Based on the projected image, visual image, and the position coordinates of the tightening execution module, the data processing module calculates the distance deviation between the tightening execution module and the target tightening point. If the deviation is lower than a preset threshold, the tightening execution module is determined to be in place, and a tightening permission signal is generated. If the deviation exceeds the preset threshold, a position misalignment alarm for the tightening execution module is generated, and a directional correction prompt is given in the projected image based on the current deviation between the tightening execution module and the target tightening point.

[0035] In conjunction with the second aspect, furthermore, the tightening torque and tightening angle during the tightening process are collected in real time by the tightening execution module to obtain a torque-angle curve; based on the time characteristics and slope changes of the torque-angle curve, it is determined whether there is abnormal operation, and when abnormal operation is found, an abnormal operation alarm signal is generated.

[0036] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0037] This invention proposes an intelligent tightening system and method based on projection guidance and machine vision. The intelligent tightening system incorporates a projection guidance module and a machine vision module, combining visual positioning, projection guidance, and tightening data to achieve visualization and precise guidance of tightening hole positions. The tightening execution module can quickly and accurately complete the tightening operation, effectively reducing the risk of incorrect or missed tightening by manual intervention. By distributing projected images and tightening parameters, precise matching and automatic execution of parameters during the tightening process are achieved, avoiding the complexity and error-prone nature of manual parameter configuration and ensuring that each bolt is tightened correctly according to process requirements. Simultaneously, this invention also enables closed-loop monitoring of the tightening process, collecting tightening data in real time. If deviations or abnormalities occur, the system can automatically alarm and halt operation, ensuring that abnormalities are detected and handled promptly, improving assembly safety and reliability. Attached Figure Description

[0038] Figure 1 The figure shown is a schematic diagram of an intelligent tightening system based on projection guidance and machine vision provided in an embodiment of the present invention;

[0039] Figure 2 The diagram shown is a flowchart illustrating the steps of a control method for an intelligent tightening system based on projection guidance and machine vision, according to an embodiment of the present invention.

[0040] Figure 1 In the middle, 1-industrial control computer, 2-projection device, 3-industrial camera, 4-tightening controller, 5-tightening machine, 6-workpiece to be tightened. Detailed Implementation

[0041] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0042] Example 1

[0043] This embodiment introduces an intelligent tightening system based on projection guidance and machine vision, such as... Figure 1 As shown, it mainly includes: a data processing module, a projection guidance module, a machine vision module, and a tightening execution module.

[0044] In this embodiment of the invention, the data processing module can be an industrial control computer 1. The data processing module is mainly used to process and store the projected images from the projection guidance module, the visual images acquired by the machine vision module, and the tightening data acquired by the tightening execution module. Based on the visual images and tightening data, it determines the positional relationship between the tightening execution module and the workpiece, whether the tightening operation is abnormal, and generates an abnormal operation alarm signal. Furthermore, the data processing module is also used to construct and store a process database containing workpiece assembly process information. The process database includes the workpiece's CAE file, the detailed sequence of the workpiece assembly process, and tightening-related parameter configurations. The process database can be obtained by collecting existing workpiece assembly files and combining them with existing big data analysis technology for data analysis. These files provide the workpiece's geometric information, hole distribution, bolt connection positions, and corresponding tightening sequences.

[0045] The projection guidance module uses a projection device 2, such as a projector. The projection guidance module responds to the projection signal of the data processing module and projects the tightening hole position and process status information into the surface of the workpiece to be tightened in the form of an image. The projected image guides the tightening position of the workpiece, prompts key information of the tightening operation, and provides alarm prompts for abnormal operation, so as to realize the projection guidance of the entire tightening process.

[0046] In this embodiment of the invention, the projector can be replaced by laser markers, head-mounted AR display devices, etc., which allows for flexible guidance methods.

[0047] The machine vision module uses an industrial camera 3 to acquire visual images of the workpiece 6 to be tightened, detect and match the workpiece to be tightened, identify the tightening holes on the workpiece and the position of the tightening execution module, and work with the data processing module and projection guidance module to better perform intelligent tightening operations.

[0048] The tightening execution module mainly includes a tightening controller 4 and a tightening machine 5, which are used to perform tightening operations and collect tightening data. Specifically, the tightening controller obtains the tightening operation sequence, tightening operation and tightening parameters sent by the data acquisition module. In response to the tightening permission signal, it automatically sends the tightening parameters to the tightening machine, completes the current tightening parameter setting, and controls the tightening machine to perform the tightening operation.

[0049] The tightening tools and methods of the tightening execution module are not limited to manual tightening machines, and can include manual tightening tools, automated robotic arms, etc. This invention does not limit the tightening execution method or bolt tightening scenario. The core inventive point of this invention lies in projection / visual guidance + closed-loop control of tightening parameters, tightening sequence, and tightening results + real-time error prevention and leakage prevention mechanisms.

[0050] Example 2

[0051] This embodiment introduces a control method for an intelligent tightening system based on projection guidance and machine vision, such as... Figure 1 As shown, the specific steps include the following:

[0052] Step 1: Establish a process database containing complete assembly process information.

[0053] This invention collects existing assembly process documents (such as various workpiece drawings, employee operation manuals, etc.) and manual assembly experience data as raw data. It uses big data analysis technology to perform semantic analysis, feature extraction and other processing on the raw data to obtain the geometric information of the workpiece that needs to be tightened, the distribution of holes that need to be tightened, the bolt connection positions, and the corresponding tightening sequence. It can also obtain the relevant configuration parameters of the tightening machine, including torque value, tightening angle, etc., according to the specific process requirements of each bolt hole, and finally form a complete process database.

[0054] Based on the process database, the data processing module can quickly match the bolt hole coordinates, tightening operation sequence, tightening parameters, etc. of the workpiece to be tightened, so that the tightening execution module of the system can perform the tightening operation and ensure that all tightening steps meet the design requirements.

[0055] This invention can also generate a projected image of each bolt hole position based on the geometric data of the CAE file and the step-by-step requirements of the assembly process. Each projected image corresponds to the current tightening position in a single operation, so that the projection guidance module can guide the assembly operation step by step. This invention associates and stores the generated projected images with the process parameters of the tightening machine, ensuring that during the assembly process, the tightening machine parameters can automatically call the matching projected image, providing accurate process guidance and real-time correction information for each tightening point.

[0056] Step 2: Deploy an intelligent tightening system based on projection guidance and machine vision, wherein the projection guidance module and the machine vision module are arranged according to a fixed reference.

[0057] The projector of the projection guidance module must be installed in an unobstructed location, ensuring that the projection light path completely covers all bolt hole areas of the workpiece to be tightened, and preventing the light path from being blocked by operators, tools, or workpiece structure. The industrial camera of the machine vision module is fixed in a position that can simultaneously observe the projected marks and key features of the workpiece, ensuring a stable field of view and uniform illumination. All cables of all modules within the system must be kept separate from the workpiece's movement trajectory to avoid pulling, tangling, or obstructing the projection area.

[0058] Step 3: Align the camera coordinate system, projection coordinate system, and workpiece coordinate system based on the calibration plate and the projected reference image. After calibration, the projected image, machine vision inspection, and tightening positioning all operate according to the same coordinate system, which can ensure the accuracy of subsequent bolt hole projection, point recognition, and tightening execution.

[0059] Step 301: Fix the calibration plate at the tooling reference position within the system, where the tooling reference position is the fixed position of the workpiece to be tightened. Acquire images of the calibration plate using the machine vision module, process these images using the data processing module, establish a mapping relationship between the camera coordinate system and the workpiece coordinate system, and achieve alignment between the two coordinate systems.

[0060] Step 302: The preset projection reference image is projected onto the calibration plate using the projection guidance module. The machine vision module synchronously collects the projection results and detects feature points (such as hole edges and marker points) on the calibration plate. By comparing the theoretical position and the actual position of the projection reference image, the projection transformation matrix from camera coordinates to projection coordinates is calculated. The projection reference image is then subjected to perspective transformation to achieve alignment between the projection coordinate system and the camera coordinate system, thereby achieving alignment between the projection coordinate system and the workpiece coordinate system.

[0061] In this embodiment of the invention, the formula for calculating the projection transformation matrix is ​​as follows:

[0062] ;

[0063] in, Let H be the coordinates of the i-th feature point in the projected coordinate system, and let H be the projection transformation matrix. Let be the coordinates of the i-th feature point in the camera coordinate system.

[0064] Step 303: Use the calibration plate of the tightening execution module to perform tightening positioning and alignment with the workpiece coordinate system. Specifically, use the calibration plate of the tightening execution module to collect the position coordinates of the tightening execution module in real time, and use the visual images collected by the machine vision module to perform tightening positioning and alignment with the workpiece coordinate system.

[0065] Step 4: Use the machine vision module to obtain a visual image of the workpiece to be tightened, and obtain the workpiece information.

[0066] After the workpiece to be tightened enters the assembly position, the machine vision module detects the workpiece and acquires its image. The data processing module processes the visual image data acquired by the machine vision module, and determines the workpiece model and its installation posture through label recognition or shape matching to obtain workpiece information. If an incorrect workpiece model or abnormal posture is detected, the system will prompt an alarm and interrupt the process.

[0067] Step 5: Based on the workpiece information, automatically load the corresponding tightening process file from the pre-built process database. The tightening workpiece file includes the coordinates of the tightening holes of the workpiece to be tightened, the tightening operation sequence, the projection image matching the tightening operation, and the tightening parameters, etc.

[0068] Step 6: According to the tightening process document, project the images onto the surface of the workpiece to be tightened in sequence and issue the corresponding tightening parameters. Under the guidance of the projected images and the vision positioning of the industrial camera, control the tightening execution module to move to the tightening point and execute the tightening operation.

[0069] Step 601: Based on the mapping relationship between the calibrated projection coordinates and the workpiece coordinates, the projection image corresponding to the current bolt is corrected and then projected onto the surface of the workpiece to be tightened to indicate the current tightening point.

[0070] Step 602: Use an industrial camera to acquire real-time projected images and visual images of the tightening machine's end point. Obtain the tightening machine's position information through the calibration plate at the end of the tightening machine. Use the data processing module to determine whether the tightening machine has entered the projection area. When the deviation between the tightening machine's position and the current target tightening point is less than a preset threshold, it is determined that the tightening execution module is in place, and a tightening allow signal is sent to the tightening controller. If the deviation exceeds the allowable range, the system will prompt a tightening execution module position misalignment alarm, and based on the deviation between the current tightening machine position and the tightening point, provide directional correction prompts in the projected image to guide the tightening machine to adjust to the correct position.

[0071] Step 603: In response to the tightening permission signal, unlock the tightening execution module, automatically send the tightening parameters (including torque, angle, strategy, etc.) to the tightening machine, complete the current tightening parameter setting, and control the tightening machine to execute the current tightening operation. The corresponding tightening program can be automatically called through the tightening controller.

[0072] During the tightening process, the tightening machine collects tightening data in real time, including torque-angle curves, time characteristics, and slope changes, and judges whether the tightening operation is qualified according to the process judgment rules. If the tightening data is abnormal, the system immediately alarms and records the abnormal information; if the tightening data is qualified, the system moves to the next tightening point, i.e., the next bolt hole, until all bolts are tightened and all are judged to be qualified.

[0073] Step 7: The system automatically generates a complete tightening data record for this workpiece, including curve data, anomaly records, tightening parameters and traceability numbers, providing a basis for assembly quality traceability and production process analysis.

[0074] In summary, this invention addresses the challenges of difficult positioning, incorrect tightening, and missed tightening caused by frequent manual positioning during the assembly of large, complex components with multiple holes. By employing projection guidance and machine vision, this invention visualizes and precisely guides bolt hole positions (also known as tightening points or tightening holes), enabling operators to quickly and accurately complete tightening operations. This effectively reduces the operational difficulty of assembling large, complex components with multiple holes, improves positioning accuracy, reduces the risk of incorrect or missed tightening, and enhances assembly accuracy and consistency.

[0075] To address the problem of numerous tightening parameters for different workpieces and hole positions, and the ease with which manual configuration is prone to errors, this invention manages the tightening parameters for each bolt hole position through a process database and combines this with an intelligent tightening system to automatically distribute parameters, thereby achieving precise matching and automatic execution of tightening parameters and ensuring that each bolt is tightened correctly according to process requirements.

[0076] To address the issue that data acquisition and quality assessment during the tightening process are often independent of the guidance process, lacking real-time judgment and linkage alarm mechanisms, resulting in the inability to promptly identify or accurately locate anomalies, this invention provides real-time monitoring of the entire tightening operation. It collects data such as torque and angle during the tightening process and combines visual positioning, projection guidance, and tightening monitoring data. During tightening, it performs real-time judgment on positional deviations, torque anomalies, or missed tightening. If a deviation exceeds a threshold or an anomaly occurs, the system automatically alarms and stops the tightening operation, guiding the operator or robot to the correct position. This ensures that anomalies are detected and handled promptly, achieving end-to-end error prevention and omission control, significantly improving assembly safety and reliability, and reducing the learning cost for operators.

[0077] To address the issues of a lack of unified coordinate system and the difficulty in achieving precise correspondence between projection, camera, and tightening tools in traditional assembly sites, this invention achieves coordinate unification for projection guidance, visual inspection, and tightening execution through camera calibration, projection calibration, and tightening machine calibration. This enables projection guidance, visual inspection, and tightening execution to work collaboratively, ensuring the accuracy and synchronization of tightening operations and providing technical support for the high-precision assembly of complex structural components.

[0078] This invention can solve the problems of high operation difficulty, easy error in tightening sequence, omissions and complicated parameter settings in the existing multi-bolt tightening process of large and complex structural components. It realizes automatic guidance and closed-loop control of tightening position, sequence and parameters to ensure the accuracy of bolt tightening process and the reliability of tightening quality, and significantly reduce the learning cost and operation complexity of workers.

[0079] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0080] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0081] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0082] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0083] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. An intelligent tightening system based on projection guidance and machine vision, characterized in that, include: The data processing module is used to build a process database, generate tightening process files for the workpiece to be tightened based on the process database, issue projection guidance and tightening execution data based on the tightening process files, and also process and store projection images, visual images and tightening data. The projection guidance module is used to project the tightening hole position and process status information into the surface of the workpiece to be tightened in the form of an image, to guide the tightening operation and provide alarm prompts for abnormal operation. The machine vision module is used to acquire visual images of the workpiece to be tightened, detect and match the workpiece to be tightened, and identify the tightening hole positions and the position of the tightening execution module of the workpiece to be tightened. The tightening execution module is used to perform tightening operations based on the projected image, visual image, and tightening parameters, and to collect tightening data.

2. The intelligent tightening system according to claim 1, characterized in that, The process database includes CAE files for different workpieces, tightening operation sequence, and tightening parameter configuration; the tightening process file includes the coordinates of the tightening holes of the workpiece to be tightened, the tightening operation sequence, the projection image matching the tightening operation, and the tightening parameters.

3. A control method based on the intelligent tightening system according to claim 2, characterized in that, include: Alignment of camera coordinate system, projection coordinate system and workpiece coordinate system based on calibration plate and projection reference image; The machine vision module is used to acquire a visual image of the workpiece to be tightened, thereby obtaining the workpiece information. Tightening process documents are generated based on workpiece information and a pre-built process database; According to the tightening process document, the projected images are sequentially projected onto the surface of the workpiece to be tightened and the corresponding tightening parameters are issued. Under the guidance of the projected images and the visual positioning of the industrial camera, the tightening execution module is controlled to perform the tightening operation.

4. The control method for the intelligent tightening system according to claim 3, characterized in that, The alignment of the camera coordinate system, projection coordinate system, and workpiece coordinate system based on the calibration plate and projection reference image includes: The calibration plate is fixed at the tooling reference position of the intelligent tightening system. The data processing module processes the calibration plate image acquired by the machine vision module and establishes the mapping relationship between the camera coordinate system and the workpiece coordinate system. The projection guidance module projects a preset projection reference image onto the calibration board. The deviation between the theoretical position and the actual position of the projection reference image is compared with the visual image acquired by the machine vision module. The projection transformation matrix from camera coordinates to projection coordinates is calculated by detecting feature points on the calibration board. Based on the mapping relationship between the camera coordinate system and the workpiece coordinate system, and the projection transformation matrix from camera coordinates to projection coordinates, the projection coordinate system and the workpiece coordinate system are aligned. The calibration board of the tightening execution module is used to collect the position coordinates of the tightening execution module in real time, and the visual images collected by the machine vision module are used to perform tightening positioning and alignment with the workpiece coordinate system.

5. The control method for the intelligent tightening system according to claim 4, characterized in that, The expression for the projection transformation matrix from camera coordinates to projected coordinates is as follows: ； in, Let H be the coordinates of the i-th feature point in the projected coordinate system, and let H be the projection transformation matrix. Let be the coordinates of the i-th feature point in the camera coordinate system.

6. The control method for the intelligent tightening system according to claim 3, characterized in that, The process of acquiring a visual image of the workpiece to be tightened using a machine vision module, and obtaining workpiece information, includes: The machine vision module acquires visual images of the workpiece to be tightened, the data processing module processes the visual images, and the workpiece model and its installation posture are determined by label recognition or shape matching to obtain workpiece information. If an incorrect workpiece model or abnormal installation posture is detected, an alarm message will be generated.

7. The control method for the intelligent tightening system according to claim 3, characterized in that, Based on the workpiece information, CAE file, and tightening operation sequence, the data processing module generates a projection image corresponding to each tightening operation, and associates the projection image with the tightening parameters according to the tightening operation sequence.

8. The control method for the intelligent tightening system according to claim 3, characterized in that, The process involves projecting images sequentially onto the surface of the workpiece to be tightened according to the tightening process document and issuing corresponding tightening parameters. Guided by the projected images and positioned visually by an industrial camera, the tightening execution module is controlled to perform the tightening operation, including: Based on the mapping relationship between the projected coordinates and the workpiece coordinates, the projected image is corrected in position and then projected onto the surface of the workpiece to be tightened. The machine vision module acquires the projected image and the visual image of the tightening execution module in real time. Combined with the position coordinates of the tightening execution module, the data processing module determines whether the tightening execution module has entered the projection area and generates a tightening permission signal. In response to the tightening permission signal, the tightening execution module is unlocked, the tightening parameters corresponding to the projected image are sent down, and the tightening execution module is controlled to perform the current tightening operation.

9. The control method for the intelligent tightening system according to claim 8, characterized in that, The step of using the data processing module to determine whether the tightening execution module has entered the projection area and generating a tightening permission signal includes: Based on the projected image, visual image, and the position coordinates of the tightening execution module, the data processing module calculates the distance deviation between the tightening execution module and the target tightening point. If the deviation is lower than a preset threshold, the tightening execution module is determined to be in place, and a tightening permission signal is generated. If the deviation exceeds the preset threshold, a position misalignment alarm for the tightening execution module is generated, and a directional correction prompt is given in the projected image based on the current deviation between the tightening execution module and the target tightening point.

10. The control method for the intelligent tightening system according to claim 8, characterized in that, The tightening execution module collects the tightening torque and tightening angle in real time during the tightening process to obtain a torque-angle curve. Based on the time characteristics and slope changes of the torque-angle curve, it is determined whether there is any abnormal operation. If there is an abnormal operation, an abnormal operation alarm signal is generated.

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