Rotating center identification system and identification method of special-shaped pipe clamping device

Abstract

The invention discloses a rotation center identification system and identification method for a special-shaped pipe clamping device, and the system comprises a camera which is used for capturing an image of a special-shaped pipe, and a compensation light source is arranged around the camera, and is used for preventing the special-shaped pipe from generating shadow and light reflection, and improving the quality and identifiability of the image; the image acquisition unit captures the overall contour of the special-shaped pipe through a camera; and the image processing unit is used for converting the color image into a grey-scale map, removing noise in the image, improving the accuracy of edge recognition and extracting the edge information of the pipe by using an edge detection algorithm. The rotating center of the pipe is measured through the visual recognition technology, rapid and accurate positioning can be achieved, the cutting and machining efficiency is greatly improved, and the requirements of various pipes in complex shapes can be effectively met in combination with the image processing technology.

Description

Technical Field

[0001] The invention belongs to the technical field of pipe processing, and in particular relates to a rotation center recognition system and a recognition method for a special-shaped pipe clamping device. Background Art

[0002] In order to ensure the accuracy of pipe cutting, it is necessary to identify the rotation center of the pipe to ensure that the cutting tool or cutter can be accurately positioned on the center line of the pipe to avoid cutting deviation and ensure the quality and accuracy of cutting.

[0003] The existing identification of the rotation center of the pipe is manually measured using tools such as calipers. For special-shaped pipes, multiple points need to be measured and their average values ​​calculated to measure the rotation center of the pipe. The measurement efficiency is low and it is easy to affect the processing progress of the pipe. Summary of the invention

[0004] The present invention aims at solving the problems in the prior art and proposes the following technical solutions:

[0005] A rotation center recognition system and recognition method for a special-shaped pipe clamping device, comprising:

[0006] A camera is used to capture images of special-shaped pipes, and a compensating light source is arranged around the camera to avoid shadows and reflections on the special-shaped pipes and improve the quality and recognizability of the images;

[0007] An image acquisition unit, wherein the image acquisition unit captures the overall contour of the special-shaped pipe through a camera;

[0008] An image processing unit, which is used to convert a color image into a grayscale image, remove noise from the image, improve the accuracy of edge recognition, and extract edge information of the pipe using an edge detection algorithm;

[0009] a feature extraction unit, the feature extraction unit extracting a bounding box, an aspect ratio, a shape moment, and a roundness from the image;

[0010] A rotation center calculation unit, wherein the rotation center calculation unit calculates the rotation center of the extracted contour;

[0011] The regulating mechanism is used to monitor the displacement data of the rotating profile of the special-shaped pipe fixed in the clamping device, and control the rotating axis of the clamping device to keep coincidence with the rotating center of the special-shaped pipe.

[0012] As a preferred embodiment of the above technical solution, the bounding box is used to calculate the minimum circumscribed rectangle or the minimum circumscribed polygon of the special-shaped pipe, so as to understand the external shape of the pipe;

[0013] The aspect ratio is used to calculate the ratio of width to height and determine the shape characteristics of special-shaped pipes;

[0014] Shape moments are used to calculate the shape moments of an image to obtain descriptions of the shape, such as the symmetry and distortion of the shape;

[0015] Roundness is used to calculate the roundness index of special-shaped pipes to evaluate their approximate circularity. The roundness formula is:

[0016]

[0017] As a preferred embodiment of the above technical solution, the adjustment mechanism includes:

[0018] A mounting seat, wherein a lower plate, a middle plate and an upper plate are fixedly mounted on one side of the mounting seat in sequence, a laser distance measuring sensor is mounted on the side of the lower plate close to the middle plate, the laser distance measuring sensor is electrically connected to the clamping device through a controller, inner ring movable sleeves of the middle plate and the upper plate are provided with a resistance rod, an outer ring fixed sleeve of the resistance rod is provided with a baffle, an elastic member is fixedly connected between the middle plate and the baffle, one end of the resistance rod away from the laser distance measuring sensor is in contact with the outer wall of the special-shaped pipe, and the clamping device drives the special-shaped pipe to rotate to drive the resistance rod to move back and forth.

[0019] As a preferred embodiment of the above technical solution, the controller includes:

[0020] A data acquisition unit, the data acquisition unit is used to record the starting position and the ending position of the multiple displacements of the resistance rod and record them in a memory;

[0021] The data processing unit is used to filter the collected data, remove noise, ensure accuracy, and calculate the displacement difference between each reciprocating motion. The formula for calculating the displacement difference is:

[0022] Δd=d n -d n -1

[0023] where d n and d n -1 is the current and previous displacement data respectively;

[0024] The result output unit is used to present the displacement data and the difference results in the form of a chart, and control the clamping device to move the special-shaped pipe according to the displacement data to make the displacement data tend to be flat.

[0025] As a preferred embodiment of the above technical solution, the clamping device includes:

[0026] A chuck, the outer wall of the chuck is fixedly connected to a fixing seat, one side of the fixing seat is fixedly connected to an annular slide rail, the annular slide rail is concentric with the chuck, and a plurality of sliders are slidably arranged between the annular slide rail and the chuck, two adjacent sliders are fixedly connected by a connecting rod, the inner ring fixing sleeve of the slider is provided with a cylinder, the output end of the cylinder is fixedly connected to a flexible clamping block, the camera and the compensation light source are both installed inside the chuck, and the mounting seat is fixed on the fixing seat.

[0027] As a preferred embodiment of the above technical solution, the outer wall of the slider is fixedly connected to a gear ring, and the gear ring is concentric with the annular slide rail and the chuck. The outer wall of the annular slide rail is fixedly connected to a motor seat, and a motor is fixedly installed on the motor seat. The output end of the motor is fixedly connected to a gear, and the gear is meshed with the gear ring for transmission.

[0028] The identification method of the rotation center identification system of the special-shaped pipe clamping device comprises the following steps:

[0029] S1. Image acquisition:

[0030] The special-shaped pipe fixed in the clamping device is photographed by a camera, and the special-shaped pipe is supplemented with light by a compensation light source during the photographing process, thereby improving the image quality photographed by the camera;

[0031] S2. Calculation of rotation center:

[0032] The contour of the special-shaped pipe is obtained and calculated according to the image processing unit and the feature extraction unit. The calculation formula of the rotation center is:

[0033]

[0034] Where A is the area of ​​the region, (C x , C y ) are the coordinates of the center of rotation;

[0035] S3, Special-shaped pipe fine-tuning:

[0036] Several flexible clamps drive the special-shaped pipe to rotate, and the displacement data of the resistance rod is collected by the laser ranging sensor. The displacement data output by the result output unit is compared with the difference result. When it is found that one or more of the displacement data are significantly higher than the mean, the control cylinder adjusts the position of the special-shaped pipe to ensure that the rotation center of the special-shaped pipe coincides with the center of the slider.

[0037] The beneficial effects of the present invention are:

[0038] 1. The present invention measures the rotation center of the pipe through visual recognition technology, which can achieve fast and accurate positioning, greatly improve the efficiency of cutting and processing, and combine with image processing technology to effectively meet the needs of various complex-shaped pipes;

[0039] 2. The present invention can automatically fine-tune the special-shaped pipe through the adjustment mechanism to ensure that the rotation center of the special-shaped pipe coincides with the center of the slider, so that the special-shaped pipe will not suddenly approach or move away from the cutting equipment during the rotation cutting process, thereby ensuring the cutting accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 What is shown is a structural block diagram of a rotation center identification system of a special-shaped pipe clamping device in an embodiment;

[0041] Figure 2 What is shown is a schematic diagram of the structure of the clamping device in the embodiment;

[0042] Figure 3 Shown is a schematic diagram of the structure of the slider and the connecting rod in the embodiment;

[0043] Figure 4 Shown is a schematic structural diagram of the adjustment mechanism in the embodiment.

[0044] Description of reference numerals:

[0045] 10. Camera; 11. Compensation light source; 12. Image acquisition unit; 13. Image processing unit; 14. Feature extraction unit; 15. Rotation center calculation unit; 20. Chuck; 21. Fixed seat; 22. Annular slide rail; 23. Slider; 24. Cylinder; 25. Flexible clamp; 26. Connecting rod; 27. Gear ring; 28. Motor seat; 29. ​​Motor; 210. Gear; 30. Adjustment mechanism; 31. Mounting seat; 32. Lower plate; 33. Middle plate; 34. Upper plate; 35. Laser ranging sensor; 36. Resistance rod; 37. Baffle; 38. Elastic member. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0047] Example 1

[0048] like Figure 1As shown, a rotation center recognition system and recognition method for a special-shaped pipe clamping device include a camera 10, an image acquisition unit 12, an image processing unit 13, a feature extraction unit 14, a rotation center calculation unit 15 and an adjustment mechanism 30. The camera 10 is used to capture the image of the special-shaped pipe, and a compensation light source 11 is arranged around the camera 10 to avoid shadows and reflections of the special-shaped pipe and improve the quality and recognizability of the image. The image acquisition unit 12 captures the overall contour of the special-shaped pipe through the camera 10. The image processing unit 13 is used to convert the color image into a grayscale image, remove noise in the image, improve the accuracy of edge recognition, and use an edge detection algorithm to extract the edge information of the pipe. The feature extraction unit 14 extracts the bounding box, aspect ratio, shape moment and roundness from the image. The rotation center calculation unit 15 calculates the rotation center of the extracted contour. The adjustment mechanism 30 is used to monitor the displacement data of the rotation contour of the special-shaped pipe fixed in the clamping device, and control the rotation axis of the clamping device to keep coincidence with the rotation center of the special-shaped pipe.

[0049] It should be noted that the noise is removed by using a filter, such as a Gaussian filter, the edge detection algorithm used is Canny edge detection, and the feature extraction of the feature extraction unit 14 utilizes a contour detection algorithm to obtain the contour of the pipe, such as findContours in OpenCV.

[0050] Specifically, the rotation center recognition system is suitable for software tools such as OpenCV, and uses computer vision libraries such as OpenCV for image processing and feature extraction. This system can integrate the above steps into an automated script through automated scripts to achieve real-time or batch processing, set feedback mechanisms, monitor the changes in the rotation center during pipe cutting or processing in real time, and make corresponding adjustments.

[0051] like Figure 1 As shown in the figure, the bounding box is used to calculate the minimum circumscribed rectangle or minimum circumscribed polygon of the special-shaped tube in order to understand the external shape of the tube; the aspect ratio is used to calculate the ratio of width to height to determine the shape characteristics of the special-shaped tube; the shape moment is used to calculate the shape moment of the image to obtain a description of the shape, such as the symmetry and distortion of the shape; the roundness is used to calculate the roundness index of the special-shaped tube to evaluate its approximate circularity. The roundness formula is:

[0052]

[0053] It should be noted that this system can perform multi-feature fusion, specifically by assigning feature weights: assigning weights to each feature according to the importance of different features to the identification of the rotation center. Common methods include machine learning algorithms to automatically learn weights, such as decision trees or random forests; principal component analysis: using PCA to reduce feature dimensions, combining features with high correlation to form a new feature set for subsequent analysis; multidimensional feature space: drawing extracted feature points in a multidimensional space, and observing the relationship between different features through visualization methods, such as scatter plots or heat maps; by combining multiple geometric features for comprehensive analysis, the recognition accuracy of the rotation center of irregular shaped tubes can be effectively improved.

[0054] Example 2

[0055] like Figure 2 and Figure 4 As shown, a rotation center identification system and identification method for a special-shaped pipe clamping device, compared with Example 1, the adjustment mechanism 30 of this embodiment includes a mounting seat 31, and a lower plate 32, a middle plate 33 and an upper plate 34 are fixedly installed on one side of the mounting seat 31 in sequence, and a laser ranging sensor 35 is installed on the side of the lower plate 32 close to the middle plate 33, and the laser ranging sensor 35 is electrically connected to the clamping device through a controller, and the inner ring movable sleeves of the middle plate 33 and the upper plate 34 are provided with a resistance rod 36, and the outer ring fixed sleeve of the resistance rod 36 is provided with a baffle 37, and an elastic member 38 is fixedly connected between the middle plate 33 and the baffle 37, and the end of the resistance rod 36 away from the laser ranging sensor 35 is in contact with the outer wall of the special-shaped pipe, and the clamping device drives the special-shaped pipe to rotate to drive the resistance rod 36 to move back and forth.

[0056] It should be noted that the model of the laser distance sensor 35 includes but is not limited to: MSE-LT150, and the elastic member 38 is a spring.

[0057] Specifically, the clamping device drives the fixed special-shaped pipe to rotate. During the rotation of the special-shaped pipe, the force of the elastic member 38 will push the end of the resistance rod 36 to always keep in contact with the special-shaped pipe, causing the resistance rod 36 to continuously move in the inner circle of the middle plate 33 and the upper plate 34, and the laser ranging sensor 35 records and processes the displacement data of the resistance rod 36.

[0058] like Figure 2 and Figure 4 As shown, the controller includes a data acquisition unit, a data processing unit and a result output unit. The data acquisition unit is used to record the starting position and the ending position of the multiple displacements of the interference rod 36 and record them in the memory. The data processing unit is used to filter the collected data, remove noise, ensure accuracy, and calculate the displacement difference between each reciprocating motion. The displacement difference calculation formula is:

[0059] Δd=dn -d n -1

[0060] where d n and d n -1 are the current and previous displacement data respectively. The result output unit is used to present the displacement data and difference results in the form of a chart. The clamping device is controlled to move the special-shaped pipe according to the displacement data to make the displacement data tend to be flat.

[0061] Specifically, the resistance rod 36 is installed on the motion path of the object, the resistance rod 36 is connected using Arduino, a program is written to collect data, Python or MATLAB is used on the computer to process and visualize the data, and multiple reciprocating displacement data are analyzed to generate a report.

[0062] Example 3

[0063] like Figure 2 and Figure 3 As shown, the rotation center identification system and identification method of the special-shaped pipe clamping device proposed by the present invention, compared with Example 1 or Example 2, the clamping device of this embodiment includes a chuck 20, the outer wall of the chuck 20 is fixedly connected with a fixing seat 21, one side of the fixing seat 21 is fixedly connected with an annular slide rail 22, the annular slide rail 22 is concentric with the chuck 20, and a plurality of sliders 23 are slidably arranged between the annular slide rail 22 and the chuck 20, two adjacent sliders 23 are fixedly connected by a connecting rod 26, the inner ring fixed sleeve of the slider 23 is provided with a cylinder 24, the output end of the cylinder 24 is fixedly connected with a flexible clamping block 25, the camera 10 and the compensation light source 11 are both installed inside the chuck 20, and the mounting seat 31 is fixed on the fixing seat 21.

[0064] It should be noted that a plurality of sliders 23 and connecting rods 26 are combined to form an annular structure, and the flexible clamping block 25 is controlled to move by the cylinder 24. The flexible clamping block 25 is made of, but not limited to, rubber material to adapt to pipes of different shapes.

[0065] like Figure 3 As shown, the outer wall of the slider 23 is fixedly connected to a gear ring 27, which is concentric with the annular slide rail 22 and the chuck 20. The outer wall of the annular slide rail 22 is fixedly connected to a motor seat 28, on which a motor 29 is fixedly installed. The output end of the motor 29 is fixedly connected to a gear 210, which meshes with the gear ring 27 for transmission.

[0066] Specifically, the motor 29 drives the gear 210 to rotate, and through the meshing transmission between the gear 210 and the gear ring 27, the slider 23 can be driven to rotate together, thereby driving the special-shaped pipe to rotate, which is convenient for cutting, drilling and other processing procedures of the pipe.

[0067] The identification method of the rotation center identification system of the special-shaped pipe clamping device comprises the following steps:

[0068] S1. Image acquisition:

[0069] The special-shaped pipe fixed in the clamping device is photographed by the camera 10, and the compensation light source 11 is used to fill in the light of the special-shaped pipe during the photographing process to improve the image quality photographed by the camera 10;

[0070] S2. Calculation of rotation center:

[0071] The image processing unit 13 and the feature extraction unit 14 obtain the contour of the special-shaped pipe and perform calculations. The calculation formula of the rotation center is:

[0072]

[0073] Where A is the area of ​​the region, (C x , C y ) are the coordinates of the center of rotation;

[0074] S3, Special-shaped pipe fine-tuning:

[0075] A number of flexible clamps 25 drive the special-shaped pipe to rotate, and the displacement data of the resistance rod 36 is collected by the laser ranging sensor 35. The displacement data output by the result output unit is compared with the difference result. When it is found that one or more of the displacement data are significantly higher than the average, the control cylinder 24 adjusts the position of the special-shaped pipe to ensure that the rotation center of the special-shaped pipe coincides with the center of the slider 23.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. The rotation center identification system of the special-shaped pipe clamping device is characterized by: include: A camera (10), wherein the camera (10) is used to capture an image of the special-shaped pipe, and a compensation light source (11) is arranged around the camera (10) to avoid shadows and reflections on the special-shaped pipe and improve the quality and recognizability of the image; An image acquisition unit (12), wherein the image acquisition unit (12) captures the overall contour of the special-shaped pipe through a camera (10); An image processing unit (13), the image processing unit (13) is used to convert the color image into a grayscale image, remove noise in the image, improve the accuracy of edge recognition, and use an edge detection algorithm to extract edge information of the pipe; A feature extraction unit (14) extracts a bounding box, aspect ratio, shape moment and roundness from the image; A rotation center calculation unit (15), wherein the rotation center calculation unit (15) calculates the rotation center of the extracted contour; The regulating mechanism (30) is used to monitor the displacement data of the rotation profile of the special-shaped pipe fixed in the clamping device, and control the rotation axis of the clamping device to keep coincidence with the rotation center of the special-shaped pipe.

2. The rotation center identification system of the special-shaped pipe clamping device according to claim 1 is characterized in that: The bounding box is used to calculate the minimum circumscribed rectangle or minimum circumscribed polygon of the special-shaped tube in order to understand the external shape of the tube; The aspect ratio is used to calculate the ratio of width to height and determine the shape characteristics of special-shaped pipes; Shape moments are used to calculate the shape moments of an image to obtain descriptions of the shape, such as the symmetry and distortion of the shape; Roundness is used to calculate the roundness index of special-shaped pipes to evaluate their approximate circularity. The roundness formula is:

3. The rotation center identification system of the special-shaped pipe clamping device according to claim 1 is characterized in that: The regulating mechanism (30) comprises: A mounting seat (31), wherein a lower plate (32), a middle plate (33) and an upper plate (34) are fixedly mounted on one side of the mounting seat (31) in sequence; a laser distance sensor (35) is mounted on a side of the lower plate (32) close to the middle plate (33); the laser distance sensor (35) is electrically connected to a clamping device through a controller; inner ring movable sleeves of the middle plate (33) and the upper plate (34) are provided with a resisting rod (36); an outer ring fixed sleeve of the resisting rod (36) is provided with a baffle (37); an elastic member (38) is fixedly connected between the middle plate (33) and the baffle (37); an end of the resisting rod (36) away from the laser distance sensor (35) is in contact with the outer wall of the special-shaped pipe; the clamping device drives the special-shaped pipe to rotate to drive the resisting rod (36) to reciprocate.

4. The rotation center identification system of the special-shaped pipe clamping device according to claim 3 is characterized in that: The controller includes: A data acquisition unit, the data acquisition unit is used to record the starting position and the ending position of the multiple displacements of the interference rod (36), and record them in a memory; The data processing unit is used to filter the collected data, remove noise, ensure accuracy, and calculate the displacement difference between each reciprocating motion. The formula for calculating the displacement difference is: Δd=d n -d n -1 where d n and d n -1 is the current and previous displacement data respectively; The result output unit is used to present the displacement data and the difference results in the form of a chart, and control the clamping device to move the special-shaped pipe according to the displacement data to make the displacement data tend to be flat.

5. The rotation center identification system of the special-shaped pipe clamping device according to claim 3 is characterized in that: The clamping device includes: A chuck (20), wherein the outer wall of the chuck (20) is fixedly connected to a fixing seat (21), one side of the fixing seat (21) is fixedly connected to an annular slide rail (22), the annular slide rail (22) is concentric with the chuck (20), and a plurality of sliders (23) are slidably arranged between the annular slide rail (22) and the chuck (20), two adjacent sliders (23) are fixedly connected by a connecting rod (26), an inner ring fixing sleeve of the slider (23) is provided with a cylinder (24), an output end of the cylinder (24) is fixedly connected to a flexible clamping block (25), the camera (10) and the compensation light source (11) are both installed inside the chuck (20), and the mounting seat (31) is fixed on the fixing seat (21).

6. The rotation center identification system of the special-shaped pipe clamping device according to claim 5, characterized in that: The outer wall of the slider (23) is fixedly connected with a gear ring (27), the gear ring (27) is concentric with the annular slide rail (22) and the chuck (20), the outer wall of the annular slide rail (22) is fixedly connected with a motor seat (28), a motor (29) is fixedly mounted on the motor seat (28), an output end of the motor (29) is fixedly connected with a gear (210), and the gear (210) is meshed with the gear ring (27) for transmission.

7. The identification method of the rotation center identification system of the special-shaped pipe clamping device according to any one of claims 1 to 6, characterized in that: The following steps are included: S1. Image acquisition: The special-shaped pipe fixed in the clamping device is photographed by a camera (10), and during the photographing process, a compensation light source (11) is used to supplement the special-shaped pipe with light, thereby improving the image quality photographed by the camera (10); S2. Calculation of rotation center: The contour of the special-shaped pipe is obtained and calculated by the image processing unit (13) and the feature extraction unit (14). The calculation formula of the rotation center is: Where A is the area of ​​the region, (C x , C y ) are the coordinates of the center of rotation; S3, Special-shaped pipe fine-tuning: A plurality of flexible clamping blocks (25) drive the special-shaped pipe to rotate, and the displacement data of the abutment rod (36) is collected by a laser distance measuring sensor (35). The displacement data output by the result output unit is compared with the difference result. When it is found that one or more displacement data are obviously higher than the average value, the cylinder (24) is controlled to adjust the position of the special-shaped pipe to ensure that the rotation center of the special-shaped pipe coincides with the center of the slider (23).

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