CN116468662A - Bolt pretightening force detection method, system and computer readable storage medium - Google Patents
Bolt pretightening force detection method, system and computer readable storage medium Download PDFInfo
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Abstract
The application discloses a bolt pretightening force detection method, a bolt pretightening force detection system and a computer readable medium, wherein the method is applied to the bolt pretightening force detection system and comprises the following steps: acquiring a bolt image sent by a CMOS camera; performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image; performing image conversion processing on the new bolt image to obtain an HSV channel space image, and determining a characteristic channel threshold value of the HSV channel space image; determining an interested region according to the characteristic channel threshold value, and acquiring a characteristic image corresponding to the interested region; determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest, and determining a bolt pre-tightening angle based on the target contour; and determining a target pretightening force value according to the bolt attribute parameters and the bolt pretightening angle. According to the method, the bolt pretightening force is intelligently calculated based on the bolt image acquired by the CMOS camera, and compared with a traditional manual detection method, the method can improve the detection precision of the pretightening force.
Description
Technical Field
The present invention relates to the field of mechanical state detection and maintenance technologies, and in particular, to a method, a system, and a computer readable storage medium for detecting bolt pretightening force.
Background
The bolt connection mode has the advantages of high interchangeability, low cost, convenient installation and the like, and is widely applied to the connection of parts of various mechanical systems. However, if the problems of loosening of bolts, insufficient pretightening force and the like occur in a mechanical system, equipment is stopped due to light weight, and financial loss is caused due to heavy weight. In traditional mechanical system production workshops, detection of bolt pretightening force is needed manually, and bolts which do not meet pretightening force conditions are pretightened by using a torque wrench, so that loosening of the bolts of a mechanical system is avoided, however, the method consumes certain labor cost, and the problems of low pretightening force detection precision, large pretightening error and the like exist.
Disclosure of Invention
The embodiment of the application provides a bolt pretightening force detection method, a system and a computer readable storage medium, which can effectively improve the pretightening force detection precision.
In a first aspect, an embodiment of the present application provides a method for detecting a bolt pretightening force, which is applied to a bolt pretightening force detection system, where the bolt pretightening force detection system is connected to a CMOS camera, and the method is characterized in that the method includes:
acquiring a bolt image sent by the CMOS camera;
performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image;
performing image conversion processing on the new bolt image to obtain an HSV channel space image, and determining a characteristic channel threshold value of the HSV channel space image;
determining an interested region according to the characteristic channel threshold value, and acquiring a characteristic image corresponding to the interested region;
determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest, and determining a bolt pre-tightening angle based on the target contour;
and determining a target pretightening force value according to the bolt attribute parameters and the bolt pretightening angle.
In some embodiments, the bolt pretightening force detection system is connected with a manipulator, and after the target pretightening force value is determined according to the bolt attribute parameter and the bolt pretightening angle, the bolt pretightening force detection method further includes:
determining a reference pre-tightening force value according to a preset relation mapping table and the bolt pre-tightening angle, wherein the relation mapping table represents the mapping relation between the pre-tightening force value and the pre-tightening angle of the bolt;
and when the target pretightening force value is smaller than the reference pretightening force value, controlling the manipulator to rotate the target bolt corresponding to the bolt image, so that the current pretightening force value of the target bolt reaches the reference pretightening force value.
In some embodiments, the bolt pretension detection method further comprises:
acquiring the position information of the target bolt under the condition that the target pre-tightening force value is smaller than the reference pre-tightening force value;
and generating alarm information according to the position information, the bolt attribute parameters and the target pretightening force value.
In some embodiments, the performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image includes:
performing image perspective transformation on the bolt image to obtain an intermediate image;
and carrying out image smoothing processing on the intermediate image to obtain the new bolt image.
In some embodiments, the performing image smoothing on the intermediate image to obtain the new bolt image is obtained according to the following formula:
wherein I is the intermediate image, J is the new bolt image, p and q are coordinates of pixels in the intermediate image, I p And f is a spatial weight distribution function, and g is a pixel local range weight distribution function for the pixel value corresponding to the coordinate p in the intermediate image.
In some embodiments, the determining the region of interest according to the characteristic channel threshold is obtained according to the following formula:
wherein T (h, s, v) is the characteristic channel threshold, R i (x, y) is the pixel value of the pixel point of the region of interest, T max (h, s, v) and T min (h, s, v) are an upper channel threshold and a lower channel threshold of the HSV channel spatial image, respectively.
In some embodiments, before the determining the target contour of the feature image according to the preset contour acquisition algorithm and the region of interest, the bolt pretightening force detection method further includes:
and corroding the characteristic image by using a rectangular mask with a preset size to obtain a new characteristic image.
In a second aspect, an embodiment of the present application provides a bolt pretension detection system, including:
the image acquisition module is used for acquiring a bolt image sent by the CMOS camera;
the image preprocessing module is used for preprocessing the image of the bolt image according to a preset rule to obtain a preprocessed new bolt image;
the characteristic channel threshold determining module is used for performing image conversion processing on the new bolt image to obtain an HSV channel space image and determining a characteristic channel threshold of the HSV channel space image;
the characteristic image acquisition module is used for determining an interested region according to the characteristic channel threshold value and acquiring a characteristic image corresponding to the interested region;
the bolt pre-tightening angle determining module is used for determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest and determining a bolt pre-tightening angle based on the target contour;
the pretightening force value determining module is used for determining a target pretightening force value according to the bolt attribute parameters and the bolt pretightening angle.
In a third aspect, an embodiment of the present application provides a bolt pretightening force detection system, including: the bolt pretension detection method according to the first aspect is implemented when the processor executes the computer program.
In a third aspect, embodiments of the present application further provide a computer readable storage medium storing computer executable instructions for performing the bolt preload detection method according to the first aspect.
The embodiment of the application provides a bolt pretightening force detection method, a bolt pretightening force detection system and a computer readable medium, wherein the method is applied to the bolt pretightening force detection system and comprises the following steps: acquiring a bolt image sent by the CMOS camera; performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image; performing image conversion processing on the new bolt image to obtain an HSV channel space image, and determining a characteristic channel threshold value of the HSV channel space image; determining an interested region according to the characteristic channel threshold value, and acquiring a characteristic image corresponding to the interested region; determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest, and determining a bolt pre-tightening angle based on the target contour; and determining a target pretightening force value according to the bolt attribute parameters and the bolt pretightening angle. According to the bolt pretightening force intelligent detection method and device, intelligent calculation of the bolt pretightening force can be achieved based on the bolt image obtained by the CMOS camera, and compared with a traditional manual detection method, the pretightening force intelligent detection method and device can effectively improve detection accuracy of pretightening force.
Drawings
FIG. 1 is a flow chart of steps of a method for detecting bolt pretension according to an embodiment of the present application;
FIG. 2 is a flowchart illustrating steps for pre-tightening a target bolt according to another embodiment of the present application;
FIG. 3 is a flowchart illustrating steps for generating alert information provided by another embodiment of the present application;
FIG. 4 is a flowchart illustrating steps for image preprocessing of bolt images according to another embodiment of the present application;
FIG. 5 is a flowchart of steps for obtaining a new feature image provided in another embodiment of the present application;
FIG. 6 is a schematic view of imaging coordinates of a bolt preload detection system according to another embodiment of the present application;
FIG. 7 is a schematic diagram of a bolt pretension detection system according to another embodiment of the present application;
fig. 8 is a block diagram of a bolt pretension detecting system according to another embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
It will be appreciated that although functional block diagrams are depicted in the device diagrams, logical sequences are shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the block diagrams in the device. The terms first, second and the like in the description, in the claims and in the above-described figures, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.
At present, the bolt connection mode is widely applied to the connection of parts of various mechanical systems due to the advantages of high interchangeability, low cost, convenient installation and the like. However, if the problems of loosening of bolts, insufficient pretightening force and the like occur in a mechanical system, equipment is stopped due to light weight, and financial loss is caused due to heavy weight. In traditional mechanical system production workshops, detection of bolt pretightening force is needed manually, and bolts which do not meet pretightening force conditions are pretightened by using a torque wrench, so that loosening of the bolts of a mechanical system is avoided, however, the method consumes certain labor cost, and the problems of low pretightening force detection precision, large pretightening error and the like exist.
In order to solve the above-mentioned existing problems, the embodiments of the present application provide a bolt pretightening force detection method, a bolt pretightening force detection system, and a computer readable medium, where the method is applied to the bolt pretightening force detection system, and the method includes: acquiring a bolt image sent by the CMOS camera; performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image; performing image conversion processing on the new bolt image to obtain an HSV channel space image, and determining a characteristic channel threshold value of the HSV channel space image; determining an interested region according to the characteristic channel threshold value, and acquiring a characteristic image corresponding to the interested region; determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest, and determining a bolt pre-tightening angle based on the target contour; and determining a target pretightening force value according to the bolt attribute parameters and the bolt pretightening angle. According to the bolt pretightening force intelligent detection method and device, intelligent calculation of the bolt pretightening force can be achieved based on the bolt image obtained by the CMOS camera, and compared with a traditional manual detection method, the pretightening force intelligent detection method and device can effectively improve detection accuracy of pretightening force.
Embodiments of the present application are further described below with reference to the accompanying drawings.
As shown in fig. 1, fig. 1 is a flowchart illustrating steps of a bolt pre-tightening force detection method according to an embodiment of the present application, and the embodiment of the present application provides a bolt pre-tightening force detection method applied to a bolt pre-tightening force detection system 700 shown in fig. 7, where the bolt pre-tightening force detection system 700 is connected to a CMOS camera 770, and the method includes, but is not limited to, the following steps:
step S110, acquiring a bolt image sent by a CMOS camera;
step S120, performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image;
step S130, performing image conversion processing on the new bolt image to obtain an HSV channel space image, and determining a characteristic channel threshold value of the HSV channel space image;
step S140, determining a region of interest according to a characteristic channel threshold value, and acquiring a characteristic image corresponding to the region of interest;
step S150, determining a target contour of a characteristic image according to a preset contour acquisition algorithm and a region of interest, and determining a bolt pre-tightening angle based on the target contour;
and step S160, determining a target pre-tightening force value according to the bolt attribute parameters and the bolt pre-tightening angle.
It can be understood that after the bolt image is obtained by the CMOS camera, the feature extraction cannot be directly performed on the bolt image, because the CMOS camera may have problems such as perspective deformation and the like, and irrelevant information exists in the obtained bolt image, so that the authenticity of the bolt image is affected, the bolt image needs to be subjected to image preprocessing according to a preset rule, and a new preprocessed bolt image is obtained, so that the usability of the subsequent new bolt image is improved; performing image conversion processing on the new bolt image to obtain an HSV channel space image, and determining a characteristic channel threshold value of the HSV channel space image; determining an interested region according to the characteristic channel threshold value, and acquiring a characteristic image corresponding to the interested region; determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest, and determining a bolt pre-tightening angle based on the target contour; according to the bolt attribute parameters and the bolt pre-tightening angle, the target pre-tightening force value is determined, that is, the bolt pre-tightening force is intelligently calculated based on the bolt image obtained by the CMOS camera, and compared with a traditional manual detection method, the detection precision of the pre-tightening force can be effectively improved.
It should be noted that, the embodiment of the present application is not limited to a specific method for performing image preprocessing on the bolt image, and may be performing image random number rotation processing, smoothing processing, or image binarization processing on the bolt image, and a specific mode for performing image preprocessing may be selected by a person skilled in the art according to actual situations.
It should be noted that, the embodiment of the present application does not limit the specific content of the bolt attribute parameter, and may include bolt material information, bolt contact surface state information, bolt model information, and the like, which may be determined by a person skilled in the art according to actual situations.
In addition, it should be noted that, before step S110 is performed, that is, before the bolt image is acquired by the CMOS camera, the method provided in the embodiment of the present application may further include: performing system calibration on the bolt pretightening force detection system, wherein the system calibration can comprise internal parameter calibration and external parameter hand-eye calibration of the CMOS camera, wherein the internal parameter calibration of the CMOS camera can effectively avoid distortion of a lens of the CMOS camera, influences the precision of feature extraction realized by a later algorithm, and further influences the calculation precision of pretightening angles; the external reference hand-eye calibration is used for solving the problem that a later-stage bolt pretightening force detection system is deployed in a digital intelligent manufacturing and operation and maintenance factory, and a manipulator can accurately position and pretighten the bolts. Before the CMOS camera calibration, a pixel coordinate system PCS (O-uv), an image coordinate system IPCS (O-XY), a camera coordinate system CCS (O-XcYcZc), a manipulator coordinate system RCS (O-XrYrZr) and a world coordinate system SCS (O-XwYwZw) are established, and after the system calibration is executed, an imaging coordinate diagram of the bolt pretightening force detection system is shown in FIG. 6.
It should be noted that, the region of interest is determined according to the characteristic channel threshold value, and is obtained according to the following formula:
wherein T (h, s, v) is a characteristic channel threshold, R i (x, y) is the pixel value of the pixel point of the region of interest, T max (h, s, v) and T min (h, s, v) are the upper and lower channel thresholds, respectively, of the HSV channel spatial image. It can be understood that, in the threshold range of the upper channel threshold and the lower channel threshold, the pixel values of the pixel points in the region of interest are returned to 255 and displayed as white; the other areas will appear black with a return value of 0. At this time, the white region is the region of interest of the image, and at this time, the region of interest is an 8-bit single-channel image.
It should be noted that, the preset contour obtaining algorithm is not limited in the embodiment of the present application, and may be a circular contour obtaining function cv2.findcontours () preset by OpenCV software, which is selected by a person skilled in the art according to the actual situation, and is not limited herein.
In addition, referring to fig. 2 and 7, in an embodiment, the bolt pretension detection system 700 is connected to the robot 780, and after performing step S160 in the embodiment shown in fig. 1, the bolt pretension detection method further includes, but is not limited to, the following steps:
step S210, determining a reference pre-tightening force value according to a preset relation mapping table and a pre-tightening angle of the bolt, wherein the relation mapping table represents the mapping relation between the pre-tightening force value of the bolt and the pre-tightening angle;
and step S220, when the target pretightening force value is smaller than the reference pretightening force value, controlling the manipulator to rotate the target bolt corresponding to the bolt image so as to enable the current pretightening force value of the target bolt to reach the reference pretightening force value.
It can be understood that the relation mapping table characterizes the mapping relation between the pretightening force value and pretightening angle of the bolt, can be used for establishing a bolt pretightening standard angle database based on factors such as connecting piece and bolt materials, contact surface states, bolt types and the like, is established based on the corresponding relation between the standard pretightening angle in the bolt pretightening standard angle database and the corresponding pretightening force value, and can be applied to the operation and maintenance of later-stage equipment and pretightening force detection. In this embodiment, a reference pre-tightening force value is determined according to a preset relation mapping table and a bolt pre-tightening angle, wherein when the target pre-tightening force value is smaller than the reference pre-tightening force value, it indicates that a target bolt corresponding to the current target pre-tightening force value is in a loose state, a manipulator is controlled to rotate the target bolt corresponding to the bolt image, and pre-tightening is performed on the target bolt, so that the current pre-tightening force value of the target bolt reaches the reference pre-tightening force value.
Additionally, referring to FIG. 3, in some embodiments, the bolt pretension detection method further includes, but is not limited to, the steps of:
step S310, acquiring the position information of a target bolt under the condition that the target pretightening force value is smaller than the reference pretightening force value;
step S320, alarm information is generated according to the position information, the bolt attribute parameters and the target pretightening force value.
It can be understood that under the condition that the target pre-tightening force value is smaller than the reference pre-tightening force value, the condition that the target bolt pre-tightening force is insufficient is indicated, the target bolt is in a loose state, the position information of the target bolt is obtained, and the alarm information is generated according to the position information, the bolt attribute parameters and the target pre-tightening force value, so that a system manager can be effectively reminded of timely finding and overhauling or controlling the intelligent maintenance of the manipulator, and the safety performance of mechanical equipment where the target bolt is located is improved.
In addition, referring to fig. 4, in an embodiment, step S120 in the embodiment shown in fig. 1 includes, but is not limited to, the following steps:
step S410, performing image perspective transformation processing on the bolt image to obtain an intermediate image;
in step S420, image smoothing processing is performed on the intermediate image to obtain a new bolt image.
It can be understood that after the bolt image is obtained by the CMOS camera, the feature extraction cannot be directly performed on the bolt image, because the CMOS camera may have problems such as perspective deformation, performing image perspective transformation processing on the bolt image to obtain an intermediate image, and correcting the bolt image, thereby avoiding the influence of the perspective deformation of the CMOS camera; in the production operation and maintenance process of the bolt, dust and other interference possibly exist in the bolt, noise exists in the obtained bolt image, if the region of interest and the feature extraction are directly carried out on the bolt image, the image noise influences the edge feature extraction precision in the image region of interest extraction process, and finally influences the calculation precision of the pretightening angle, so that the bolt image needs to be subjected to smoothing processing to solve the noise problem, after the intermediate image is obtained, the intermediate image is subjected to image smoothing processing to obtain a new bolt image, irrelevant information in the bolt image can be eliminated, useful real information is recovered, the detectability of related information is enhanced, data is simplified to the maximum extent, and the reliability of the application of the subsequent new bolt image is improved.
The bolt image is subjected to image perspective transformation processing, and an intermediate image is obtained according to the following formula:
h i ＝Th j ；
wherein h is i H is the coordinates of each pixel point of the bolt image j＝ [u j ,v j ,1]，h i ＝[u i ,v i ,1]For the coordinates of each pixel point of the intermediate image after the image perspective transformation, T is a perspective transformation matrix, and the expression of T is:
at a 33 In the case of =0, T is obtained according to the following formula:
the intermediate image is subjected to image smoothing processing, and a new bolt image is obtained according to the following formula:
wherein I is an intermediate image, J is a new bolt image, p and q are coordinates of pixels in the intermediate image, I p And f is a spatial weight distribution function, and g is a pixel local range weight distribution function for the pixel value corresponding to the coordinate p in the intermediate image. It can be appreciated that, because the combined bilateral filtering has the advantages of smooth stripes, clear edges, good contrast and good structural integrity, the embodiment of the application utilizes the combined bilateral filtering algorithm to carry out smoothing treatment on the intermediate image, thereby realizing effective noise reduction on the intermediate image.
In addition, referring to fig. 5, in an embodiment, before executing step S150 in the embodiment shown in fig. 1, the method for detecting a bolt pretightening force according to the embodiment of the present application further includes, but is not limited to, the following steps:
step S510, corroding the characteristic image by utilizing a rectangular mask with a preset size to obtain a new characteristic image.
It can be understood that, before step S150 is performed, that is, before the target contour of the feature image is determined according to the preset contour acquisition algorithm and the region of interest, the feature image is corroded by using a rectangular mask with a preset size to obtain a new feature image, so that independent pixel points at the edge of the feature image can be eliminated, and the edge of the feature image is smoother, thereby improving the accuracy of the target contour.
It should be noted that, the embodiment of the present application is not limited to the specific size of the rectangular mask, and the size may be 3*3, which is determined by those skilled in the art according to practical situations.
In addition, referring to fig. 7, fig. 7 is a schematic block diagram of a bolt pretightening force detection system according to another embodiment of the present application, in an embodiment, a bolt pretightening force detection system 700 is provided, and the bolt pretightening force detection system 700 includes:
the image acquisition module 710, the image acquisition module 710 is used for acquiring the bolt image sent by the CMOS camera;
the image preprocessing module 720 is used for performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image;
the characteristic channel threshold determining module 730, the characteristic channel threshold determining module 730 is configured to perform image conversion processing on the new bolt image, obtain an HSV channel space image, and determine a characteristic channel threshold of the HSV channel space image;
the feature image obtaining module 740 is configured to determine a region of interest according to a feature channel threshold, and obtain a feature image corresponding to the region of interest;
the bolt pre-tightening angle determining module 750 is used for determining a target contour of the feature image according to a preset contour acquisition algorithm and the region of interest, and determining a bolt pre-tightening angle based on the target contour;
the pretightening force value determining module 760, the pretightening force value determining module 760 is configured to determine a target pretightening force value according to the bolt attribute parameter and the bolt pretightening angle.
In addition, referring to fig. 8, fig. 8 is a structural diagram of a bolt pretightening force detection system according to another embodiment of the present application, and one embodiment of the present application further provides a bolt pretightening force detection system 800, where the bolt pretightening force detection system 800 includes: memory 810, processor 720, and computer programs stored on memory 810 and executable on processor 820.
Processor 820 and memory 810 may be connected by a bus or other means.
The non-transitory software program and instructions required to implement the bolt preload detection method of the above embodiments are stored in the memory 810, and when executed by the processor 820, the bolt preload detection method applied to the bolt preload detection system 800 in the above embodiments is performed, for example, the method steps S110 to S160 in fig. 1, the method steps S210 to S220 in fig. 2, the method steps S310 to S320 in fig. 3, the method steps S410 to S420 in fig. 4, and the method step S510 in fig. 5 described above are performed.
The above described apparatus embodiments are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
Furthermore, an embodiment of the present application provides a computer readable storage medium storing computer executable instructions that are executed by a processor or controller, for example, by a processor 820 in the embodiment of the bolt preload detection system 800, which may cause the processor 820 to perform the bolt preload detection method applied to the bolt preload detection system 800 in the embodiment described above, for example, to perform the method steps S110 to S160 in fig. 1, the method steps S210 to S220 in fig. 2, the method steps S310 to S320 in fig. 3, the method steps S410 to S420 in fig. 4, and the method step S510 in fig. 5 described above. Those of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.
Claims (10)
1. The bolt pretightening force detection method is applied to a bolt pretightening force detection system, and the bolt pretightening force detection system is connected with a CMOS camera, and is characterized in that the method comprises the following steps:
acquiring a bolt image sent by the CMOS camera;
performing image preprocessing on the bolt image according to a preset rule to obtain a preprocessed new bolt image;
performing image conversion processing on the new bolt image to obtain an HSV channel space image, and determining a characteristic channel threshold value of the HSV channel space image;
determining an interested region according to the characteristic channel threshold value, and acquiring a characteristic image corresponding to the interested region;
determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest, and determining a bolt pre-tightening angle based on the target contour;
and determining a target pretightening force value according to the bolt attribute parameters and the bolt pretightening angle.
2. The method for detecting a bolt pretension according to claim 1, wherein the bolt pretension detection system is connected to a manipulator, and after the target pretension value is determined according to the bolt attribute parameter and the bolt pretension angle, the method further comprises:
determining a reference pre-tightening force value according to a preset relation mapping table and the bolt pre-tightening angle, wherein the relation mapping table represents the mapping relation between the pre-tightening force value and the pre-tightening angle of the bolt;
and when the target pretightening force value is smaller than the reference pretightening force value, controlling the manipulator to rotate the target bolt corresponding to the bolt image, so that the current pretightening force value of the target bolt reaches the reference pretightening force value.
3. The bolt pretension detection method according to claim 2, characterized in that the method further comprises:
acquiring the position information of the target bolt under the condition that the target pre-tightening force value is smaller than the reference pre-tightening force value;
and generating alarm information according to the position information, the bolt attribute parameters and the target pretightening force value.
4. The method for detecting bolt pretightening force according to claim 1, wherein the performing image pretreatments on the bolt image according to a preset rule to obtain a new bolt image after pretreatments, includes:
performing image perspective transformation on the bolt image to obtain an intermediate image;
and carrying out image smoothing processing on the intermediate image to obtain the new bolt image.
5. The method for detecting bolt pretightening force according to claim 4, wherein the image smoothing process is performed on the intermediate image to obtain the new bolt image, and the new bolt image is obtained according to the following formula:
wherein I is the intermediate image, J is the new bolt image, p and q are coordinates of pixels in the intermediate image, I p And f is a spatial weight distribution function, and g is a pixel local range weight distribution function for the pixel value corresponding to the coordinate p in the intermediate image.
6. The method for detecting the pretightening force of the bolt according to claim 2, wherein the region of interest is determined according to the characteristic channel threshold value, and is obtained according to the following formula:
wherein T (h, s, v) is the characteristic channel threshold, R i (x, y) is the pixel value of the pixel point of the region of interest, T max (h, s, v) and T min (h, s, v) are an upper channel threshold and a lower channel threshold of the HSV channel spatial image, respectively.
7. The bolt pretension detection method according to claim 1, wherein before the target profile of the feature image is determined according to a preset profile acquisition algorithm and the region of interest, the method further includes:
and corroding the characteristic image by using a rectangular mask with a preset size to obtain a new characteristic image.
8. A bolt pretension detection system, comprising:
the image acquisition module is used for acquiring a bolt image sent by the CMOS camera;
the image preprocessing module is used for preprocessing the image of the bolt image according to a preset rule to obtain a preprocessed new bolt image;
the characteristic channel threshold determining module is used for performing image conversion processing on the new bolt image to obtain an HSV channel space image and determining a characteristic channel threshold of the HSV channel space image;
the characteristic image acquisition module is used for determining an interested region according to the characteristic channel threshold value and acquiring a characteristic image corresponding to the interested region;
the bolt pre-tightening angle determining module is used for determining a target contour of the characteristic image according to a preset contour acquisition algorithm and the region of interest and determining a bolt pre-tightening angle based on the target contour;
the pretightening force value determining module is used for determining a target pretightening force value according to the bolt attribute parameters and the bolt pretightening angle.
9. A bolt pretension detection system, comprising: a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the bolt preload detection method according to any one of claims 1 to 7 when executing the computer program.
10. A computer-readable storage medium storing computer-executable instructions for performing the bolt preload detection method according to any one of claims 1 to 7.
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| CN202310233005.8A CN116468662A (en) | 2023-03-10 | 2023-03-10 | Bolt pretightening force detection method, system and computer readable storage medium |
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| CN202310233005.8A CN116468662A (en) | 2023-03-10 | 2023-03-10 | Bolt pretightening force detection method, system and computer readable storage medium |
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