Thread parameter measuring device and measuring method

Abstract

The application discloses a thread parameter measuring device, which comprises a base and a stand column, the stand column is fixedly connected to the base, a rotary clamping unit is further fixedly connected to the base, a rotary sliding unit is arranged on one side of the stand column close to the rotary clamping unit, and a visual detection unit is fixedly connected to one side of the stand column away from the rotary sliding unit. The application further discloses a thread parameter measuring method, which specifically comprises the following steps: S1, clamping a workpiece to be measured; S2, image initial collection; S3, image collection based on an adaptive spiral angle search compensation algorithm based on a thread angle; S4, judging a thread type based on the collected image; S5, moving a camera to different measuring positions for collection; and S6, measuring and recording the images collected at different positions. The thread parameter measuring device solves the problem of inaccurate thread parameter measurement in the prior art.

Description

Technical Field

[0001] This invention relates to the field of measuring tool technology, specifically to a thread parameter measuring device, and also to a measuring method using the aforementioned measuring device. Background Technology

[0002] Thread inspection technology is mainly divided into two types: contact and non-contact. Traditional thread parameter measurement mostly uses contact methods, such as go / no-go gauge calibration, length measuring machines, and micrometers. These methods either have limited accuracy, measure only a single parameter, or have low inspection efficiency and high costs, failing to effectively meet the needs of the thread inspection market. Due to the huge usage and production volume of threads, traditional thread inspection methods are inefficient and struggle to inspect all threads. With the rapid advancement of image processing technology, machine vision-based non-contact thread inspection technology has emerged. This technology can acquire comprehensive thread parameters and complete dimensional information in a single inspection, offering advantages such as high inspection speed, high accuracy, and ease of automation, meeting the online inspection requirements in the production process of threaded parts. Although existing machine vision-based non-contact external thread inspection methods have been successfully applied in some industries, these existing inspection systems still have room for improvement in terms of robustness, accuracy, speed, and automation integration. Moreover, a single device cannot automatically adapt to the measurement of threaded workpieces with different helix angles, the thread parameter data obtained through this method is not highly accurate, the inspection process relies on manual operation, and wear on the threads is inevitable during the inspection process. Summary of the Invention

[0003] The purpose of this invention is to provide a thread parameter measuring device that solves the problem of low accuracy in thread parameter measurement in the prior art.

[0004] Another object of the present invention is to provide a method for measuring thread parameters using the above-described apparatus.

[0005] The first technical solution adopted in this invention is: a thread parameter measuring device, including a base and a column fixed on the base, a rotary clamping unit fixed on the base, a rotary sliding unit provided on the side of the column near the rotary clamping unit, a vision inspection unit fixed on the side of the column away from the rotary sliding unit, and also including a PLC and a processor. The PLC is electrically connected to the rotary clamping unit, the rotary sliding unit and the vision inspection unit, and the processor is electrically connected to the vision inspection unit.

[0006] The first technical solution of this invention is further characterized by:

[0007] The rotary clamping unit includes a turntable drive motor, which is fixedly connected to the base. The turntable drive motor is connected to a turntable reducer via a shaft, and the turntable reducer is connected to a pneumatic three-jaw chuck via a shaft.

[0008] The rotary sliding unit includes a pair of guide rails, which are fixed to the side of the column near the pneumatic three-jaw chuck. Each guide rail has a slider connected to it and a connecting plate fixed to it. The connecting plate is fixed to a rotary center bracket. The rotary center bracket has a through hole that coincides with the axis of the pneumatic three-jaw chuck. A sleeve passes through the through hole of the rotary center bracket, and a rotary center is connected to the end of the sleeve near the pneumatic three-jaw chuck.

[0009] The visual inspection unit includes a linear module, which is fixedly connected to the side of the column away from the pneumatic three-jaw chuck. The end of the linear module near the top of the column is connected to a module drive motor via a shaft. A turntable slider is slidably connected to the slide rail of the linear module. A turntable connecting plate is bolted to the turntable slider. An electric rotary turntable is fixedly connected to the turntable connecting plate. A turntable disk is fixedly connected to the shaft of the electric rotary turntable. A visual inspection bracket is bolted to the turntable disk. The visual inspection bracket has a "U" shaped cross-section. A camera bracket and a light source bracket are fixedly connected to both ends of the inspection bracket, respectively. The camera bracket and the light source bracket have through holes. A camera and a light source are respectively installed on the camera bracket and the light source bracket. A lens is mounted on the camera.

[0010] The axis of the through hole of the camera bracket and the light source bracket is in the same plane as the axis of the rotating tip.

[0011] The second technical solution adopted in this invention specifically includes the following steps:

[0012] S1: Clamp the workpiece to be tested;

[0013] S2: Initial image acquisition;

[0014] S3: Image acquisition is performed using an adaptive helix angle search compensation algorithm based on tooth profile angle;

[0015] S4: Determine the thread type based on the acquired image;

[0016] S5: Move the camera to different measurement positions to collect data;

[0017] S6: Measure and record images acquired at different locations.

[0018] The second technical solution of the present invention is further characterized by:

[0019] The specific process of S1 is as follows: one end of the workpiece to be tested is clamped by a pneumatic three-jaw chuck, and the height of the rotating center is adjusted by a sliding connecting plate to fix the other end of the workpiece to be tested.

[0020] The specific process of S2 is as follows: the PLC controls the linear module to move the vision inspection bracket connected to the linear module to the initial position, and the camera performs initial image acquisition of the workpiece to be tested.

[0021] The specific process of S3 is as follows:

[0022] S301: The electric rotary table controlled by PLC rotates the camera to a preset image acquisition angle for image acquisition. The preset image acquisition angle is set manually on the processor, based on the fact that the line connecting the camera and the light source is perpendicular to the axis of the rotary tip.

[0023] S302: Based on the image, calculate the tooth profile angle and record the tooth profile angle and its corresponding camera rotation angle;

[0024] S303: Determine if the preset number of image acquisitions has been reached, usually set to 5-10 times. If not, rotate the camera shooting angle according to the preset large step angle and return to S302. The preset large step angle is 1° on the processor. This value is modified by the user. The modification is based on 0.5-1 times the helix angle of the thread to be tested. If the number of acquisitions has been reached, proceed to the next step.

[0025] S304: Determine the trend of the tooth angle change to ensure that the camera can capture the maximum tooth angle during the rotation process; if the angle increases from small to large, adjust the rotation direction of the camera angle adjustment and adjust the camera angle in the opposite direction; if the angle decreases from large to small, the camera rotation direction remains unchanged; if there is a trend of change from small to large and then back to small, that is, the maximum value of the tooth angle appears, then proceed to step S307.

[0026] S305: Acquire images, then calculate the tooth profile angle and record the tooth profile angle and its corresponding camera rotation angle;

[0027] S306: Determine if the tooth angle change trend reaches a maximum point. If not, continue rotating the camera angle according to the set large increment angle and move to S305; if a maximum point appears, proceed to the next step.

[0028] S307: Rotate the camera to the camera rotation angle corresponding to the maximum value of the tooth angle in S306, then reduce it by five degrees, and start searching for the maximum tooth angle from one side of the maximum tooth angle;

[0029] S308: Acquire images, calculate tooth profile angles, and record tooth profile angles and their corresponding camera rotation angles;

[0030] S309: Determine if a maximum value has appeared in the trend of the tooth profile angle change. If not, continue to rotate the camera angle according to the preset small increment angle and turn to S308. The preset small increment angle is 0.05° on the processor. This value is modified by the user. The modification basis is set to 0.01-0.05 times the helix angle of the thread to be tested. Continue to rotate the camera angle and turn to S608. If a maximum value appears, proceed to S4.

[0031] The beneficial effects of this invention are:

[0032] The thread parameter measuring device and method of this invention solve the problem of inaccurate thread parameter measurement caused by the mismatch between the helix angle and the camera shooting angle, which results in the thread image acquired by the projection method not being the maximum projection acquisition. By combining the adaptive helix angle search compensation algorithm of this invention with the thread parameter measuring device, the problem of inaccurate thread parameter measurement caused by incorrect camera angle when capturing the thread is minimized through automatic search for the optimal shooting angle. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the thread parameter measuring device of the present invention;

[0034] Figure 2 This is a schematic diagram of the rear structure of the thread parameter measuring device of the present invention;

[0035] Figure 3 This is a schematic diagram of the connection of the visual inspection unit of the thread parameter measuring device of the present invention;

[0036] Figure 4 This is a flowchart of the thread parameter measurement method of the present invention;

[0037] Figure 5 This is a flowchart of image acquisition using the adaptive helix angle search compensation algorithm based on the tooth profile angle in the thread parameter measurement method of the present invention.

[0038] In the diagram: 1. Base; 2. Pneumatic three-jaw chuck; 3. Workpiece to be measured; 4. Camera; 5. Lens; 6. Camera bracket; 7. Vision inspection bracket; 8. Rotary center; 9. Rotary center bracket; 10. Sleeve; 11. Connecting plate; 12. Module drive motor; 13. Guide rail; 14. Linear module; 15. Electric rotary table; 16. Light source bracket; 17. Light source; 18. Column; 19. Rotary table reducer; 20. Rotary table drive motor; 21. Slider; 22. Rotary table slider; 23. Rotary table connecting plate; 24. Rotary table turntable. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1As described above, the present invention provides a thread parameter measuring apparatus, which includes a base 1 and a column 18 fixedly connected to the base 1. A rotary clamping unit is also fixedly connected to the base 1. A rotary sliding unit is disposed on the side of the column 18 close to the rotary clamping unit, and a visual detection unit is fixedly connected to the side of the column 18 away from the rotary sliding unit. The apparatus further includes a PLC and a processor, wherein the PLC is electrically connected to the rotary clamping unit, the rotary sliding unit and the visual detection unit, and the processor is electrically connected to the visual detection unit. The rotary clamping unit includes a turntable drive motor 20, which is fixedly connected to the base 1. The turntable drive motor 20 is connected to a turntable reducer 19 through a shaft, and the turntable reducer 19 is connected to a pneumatic three-jaw chuck 2 through a shaft. A workpiece 3 to be measured is clamped by the pneumatic three-jaw chuck 2 and placed vertically on a precision turntable to perform rotary motion. The rotary sliding unit includes a pair of guide rails 13, which are fixedly connected to the side of the column 18 close to the pneumatic three-jaw chuck 2. A sliding block 21 is slidably connected to each guide rail 13, the sliding block is fixedly connected to a connection plate 11, the connection plate 11 is fixedly connected to a live center bracket 9, the live center bracket 9 is provided with a through hole coaxial with the pneumatic three-jaw chuck 2, a sleeve 10 penetrates through the through hole of the live center bracket 9, and the end of the sleeve 10 close to the pneumatic three-jaw chuck 2 is connected with a live center 8.

[0041] As Figure 2 shown, the visual detection unit includes a linear module 14, which is fixedly connected to the side of the column 18 away from the pneumatic three-jaw chuck 2. The end of the linear module 14 close to the top end of the column 18 is connected to a module drive motor 12 through a shaft. The visual detection unit uses a camera 4 and a light source 17 to adjust the thread shooting angle through an electric rotary turntable 15, and can move up and down through the linear module 14 to collect images of different positions of the thread.

[0042] As Figure 3 shown, a turntable sliding block 22 is slidably connected to the slide rail of the linear module 14, the turntable sliding block 22 is connected to a turntable connection plate 23 through bolts, the electric rotary turntable 15 is fixedly connected to the turntable connection plate 23, the rotating shaft of the electric rotary turntable 15 is fixedly connected to a turntable rotary plate 24, the turntable rotary plate 24 is fixedly connected to a visual detection bracket 7 through bolts, the cross section of the visual detection bracket 7 is in a "several" shape, the two ends of the detection bracket 7 are fixedly connected with a camera bracket 6 and a light source bracket 16 respectively, the camera bracket 6 and the light source bracket 16 are provided with through holes, the camera bracket 6 and the light source bracket 16 are respectively provided with the camera 4 and the light source 17, and a lens 5 is mounted on the camera 4. The axes of the through holes of the camera bracket 6 and the light source bracket 16 are in the same plane as the axis of the live center 8. The light source 17 and the lens 5 of the camera 4 are connected together through the visual detection bracket 7, which has good consistency during measurement movement. Secondly, the visual detection bracket 7, the light source 17 and the lens 5 of the camera 4 are all disposed on the electric rotary turntable 15, and the image error caused by the helix angle is eliminated through rotation adjustment.

[0043] The thread parameter measuring device provided by this invention operates as follows: the workpiece 3 to be measured is clamped by a pneumatic three-jaw chuck 2 and placed vertically on it, undergoing rotational motion. The vision inspection unit rotates the camera 4 and the light source 17 via an electric rotary table 15, thereby adjusting the thread imaging angle and allowing it to move up and down along the linear module 14 to acquire images of different positions on the thread. This structure is strong, compact, and operates smoothly, making it suitable for inspecting threaded parts of various sizes and types.

[0044] like Figure 4 As shown, the present invention provides a method for measuring thread parameters, which specifically includes the following steps:

[0045] S1: Clamp the workpiece 3 to be tested, and use the pneumatic three-jaw chuck 2 to hold one end of the workpiece 3 to be tested, and slide the connecting plate 11 to adjust the height of the rotating center 8 to fix the other end of the workpiece 3 to be tested.

[0046] S2: Initial image acquisition. The PLC controls the linear module 14 to move the vision inspection bracket 7 connected to the linear module 14 to the initial position. The camera performs initial image acquisition on the workpiece 3 to be tested. The initial position is manually set and does not interfere with other components.

[0047] S3: Image acquisition is performed using an adaptive helix angle search and compensation algorithm based on the thread profile angle. This adjusts the angle between the camera light source axis and the thread axis (i.e., the helix angle), eliminating projection occlusion between the helical surfaces and improving the accuracy of various thread parameters measurements. Figure 5 As shown:

[0048] S301: The electric rotary table 15 is controlled by PLC to rotate the camera 4 to a preset image acquisition angle for image acquisition. The preset image acquisition angle is set manually on the processor. The setting is based on the fact that the line connecting the camera and the light source is perpendicular to the axis of the rotating tip 8.

[0049] S302: Based on the image, calculate the tooth profile angle and record the tooth profile angle and its corresponding camera rotation angle;

[0050] S303: Determine whether the number of image acquisitions has reached the preset number, usually set to 5-10. If not, rotate the camera shooting angle according to the preset large step angle and return to S302. The preset large step angle is preset to 1° on the processor. This value is modified by the user. The modification is based on 0.5-1 times the helix angle of the thread to be tested. If the number of acquisitions has been reached, proceed to the next step.

[0051] S304: Determine the change trend of the thread form angle to ensure that the camera can capture the maximum thread form angle during rotation; if the angle changes from small to large, adjust the rotation direction of the camera angle adjustment, and reversely adjust the camera angle; if the angle changes from large to small, the camera rotation direction remains unchanged; if the change trend of from small to large and then to small occurs, that is, the maximum value point of the thread form angle appears, proceed to step S307;

[0052] S305: Collect an image, then calculate the thread form angle and record the thread form angle as well as its corresponding camera rotation angle;

[0053] S306: Determine whether a maximum value point appears in the change trend of the thread form angle. If no maximum value point appears, continue to rotate the camera angle according to the set large increment angle, and go to S305; if a maximum value point appears, proceed to the next step;

[0054] S307: Rotate the camera to the camera rotation angle corresponding to the maximum thread form angle that appears in S306, then subtract five degrees, and start searching for the maximum thread form angle from one side of the maximum thread form angle;

[0055] S308: Collect an image, calculate the thread form angle and record the thread form angle as well as its corresponding camera rotation angle;

[0056] S309: Determine whether a maximum value point appears in the change trend of the thread form angle. If no maximum value point appears, continue to rotate the camera angle according to the preset small increment angle, and go to S308. The preset small increment angle is preset to 0.05° on the processor, this value can be modified by the user, and the modification basis is set to 0.01-0.05 times the helix angle of the thread to be measured; continue to rotate the camera angle, and go to S608; if a maximum value point appears, proceed to S4;

[0057] S4: Determine the thread type based on the collected images, collect thread images, and judge the thread type through a template matching scheme. Different types of threads correspond to different types of output parameters;

[0058] S5: Move the camera 4 to different measurement positions for collection;

[0059] S6: Measure and record the images collected at different positions. After the images are preprocessed, the thread data is measured and output by the measurement software, and a measurement report can be automatically generated, which includes the theoretical value, actual value, tolerance zone, deviation and out-of-tolerance of each parameter of the threaded workpiece, and can directly judge whether the measurement result is qualified, and the measurement report can also be exported to an excel file. When the workpiece to be measured is long, the height of the camera 4 and the light source 17 is changed through the linear module 14, and the spacing between adjacent positions is set according to the field of view of the camera 4.

[0060] Example 1

[0061] As Figure 1As shown, the thread parameter measuring device proposed in this embodiment includes a base 1 and a column 18 fixed on the base 1. A rotary clamping unit is also fixed on the base 1. A rotary sliding unit is provided on the side of the column 18 near the rotary clamping unit. A vision inspection unit is fixed on the side of the column 18 away from the rotary sliding unit. The device also includes a PLC and a processor. The PLC is electrically connected to the rotary clamping unit, the rotary sliding unit and the vision inspection unit. The processor is electrically connected to the vision inspection unit.

[0062] Example 2

[0063] like Figure 1 , 2 As shown in Figure 3, the thread parameter measuring device proposed in this embodiment includes a base 1 and a column 18 fixedly connected to the base 1. A rotary clamping unit is also fixedly connected to the base 1. A rotary sliding unit is provided on the side of the column 18 near the rotary clamping unit, and a vision inspection unit is fixedly connected to the side of the column 18 away from the rotary sliding unit. The device also includes a PLC and a processor. The PLC is electrically connected to the rotary clamping unit, the rotary sliding unit, and the vision inspection unit, and the processor is electrically connected to the vision inspection unit. The rotary clamping unit includes a turntable drive motor 20, which is fixedly connected to the base 1. The turntable drive motor 20 is connected to a turntable reducer 19 via a shaft, and the turntable reducer 19 is connected to a pneumatic three-jaw chuck 2 via a shaft. The rotary sliding unit includes a pair of guide rails 13, which are fixed to the column 18 on the side near the pneumatic three-jaw chuck 2. Each guide rail 13 is slidably connected to a slider 21, which is fixed to a connecting plate 11. The connecting plate 11 is fixed to a rotary center support 9. The rotary center support 9 has a through hole that coincides with the axis of the pneumatic three-jaw chuck 2. A sleeve 10 passes through the through hole of the rotary center support 9. A rotary center 8 is connected to one end of the sleeve 10 near the pneumatic three-jaw chuck 2. The visual inspection unit includes a linear module 14, which is fixedly connected to the side of the column 18 away from the pneumatic three-jaw chuck 2. A module drive motor 12 is connected to the end of the linear module 14 near the top of the column 18 via a shaft. A turntable slider 22 is slidably connected to the slide rail of the linear module 14. A turntable connecting plate 23 is bolted to the turntable slider 22. An electric rotary turntable 15 is fixedly connected to the turntable connecting plate 23. A turntable disk 24 is fixedly connected to the rotating shaft of the electric rotary turntable 15. A visual inspection bracket 7 is bolted to the turntable disk 24. The visual inspection bracket 7 has a "U"-shaped cross-section. A camera bracket 6 and a light source bracket 16 are fixedly connected to both ends of the inspection bracket 7, respectively. Both the camera bracket 6 and the light source bracket 16 have through holes. A camera 4 and a light source 17 are respectively mounted on the camera bracket 6 and the light source bracket 16. A lens 5 is mounted on the camera 4. The axis of the through hole in the camera bracket 6 and the light source bracket 16 is in the same plane as the axis of the rotating center 8.

[0064] Example 3

[0065] like Figure 4 As shown, the present invention provides a method for measuring thread parameters, which specifically includes the following steps:

[0066] S1: Clamp the workpiece to be tested 3;

[0067] S2: Initial image acquisition;

[0068] S3: Image acquisition is performed using an adaptive helix angle search compensation algorithm based on tooth profile angle;

[0069] S4: Determine the thread type based on the acquired image;

[0070] S5: Move camera 4 to different measurement positions to collect data;

[0071] S6: Measure and record images acquired at different locations.

[0072] Example 4

[0073] like Figure 4 and 5 As shown, the present invention provides a method for measuring thread parameters, which specifically includes the following steps:

[0074] S1: Clamp the workpiece 3 to be tested, and use the pneumatic three-jaw chuck 2 to hold one end of the workpiece 3 to be tested, and slide the connecting plate 11 to adjust the height of the rotating center 8 to fix the other end of the workpiece 3 to be tested.

[0075] S2: Initial image acquisition. The PLC controls the linear module 14 to move the vision inspection bracket 7 connected to the linear module 14 to the initial position. The camera performs initial image acquisition on the workpiece 3 to be tested. The initial position is manually set and does not interfere with other components.

[0076] S3: Image acquisition is performed using an adaptive helix angle search compensation algorithm based on tooth profile angle, such as... Figure 5 As shown, S301: The electric rotary table 15 is controlled by PLC to rotate the camera 4 to a preset image acquisition angle for image acquisition. The preset image acquisition angle is set manually on the processor. The setting is based on the fact that the line connecting the camera and the light source is perpendicular to the axis of the rotating tip 8.

[0077] S302: Based on the image, calculate the tooth profile angle and record the tooth profile angle and its corresponding camera rotation angle;

[0078] S303: Determine whether the number of image acquisitions has reached the preset number, usually set to 5-10. If not, rotate the camera shooting angle according to the preset large step angle and return to S302. The preset large step angle is preset to 1° on the processor. This value is modified by the user. The modification is based on 0.5-1 times the helix angle of the thread to be tested. If the number of acquisitions has been reached, proceed to the next step.

[0079] S304: Determine the trend of the tooth angle change to ensure that the camera can capture the maximum tooth angle during the rotation process; if the angle increases from small to large, adjust the rotation direction of the camera angle adjustment and adjust the camera angle in the opposite direction; if the angle decreases from large to small, the camera rotation direction remains unchanged; if there is a trend of change from small to large and then back to small, that is, the maximum value of the tooth angle appears, then proceed to step S307.

[0080] S305: Acquire images, then calculate the tooth profile angle and record the tooth profile angle and its corresponding camera rotation angle;

[0081] S306: Determine if the tooth angle change trend reaches a maximum point. If not, continue rotating the camera angle according to the set large increment angle and move to S305; if a maximum point appears, proceed to the next step.

[0082] S307: Rotate the camera to the camera rotation angle corresponding to the maximum value of the tooth angle in S306, then reduce it by five degrees, and start searching for the maximum tooth angle from one side of the maximum tooth angle;

[0083] S308: Acquire images, calculate tooth profile angles, and record tooth profile angles and their corresponding camera rotation angles;

[0084] S309: Determine if a maximum value has appeared in the trend of the tooth profile angle change. If not, continue rotating the camera angle by a preset small increment angle and proceed to S308. The preset small increment angle is preset to 0.05° on the processor. This value is modified by the user, and the modification is based on a multiple of 0.01-0.05 of the helix angle of the thread to be tested. Continue rotating the camera angle and proceed to S608. If a maximum value has appeared, proceed to S4.

[0085] S4: Determine the thread type based on the acquired image. Acquire thread images and determine the thread type using a template matching scheme. Different types of threads will output different types of parameters.

[0086] S5: Move camera 4 to different measurement positions to collect data;

[0087] S6: Measure and record images acquired at different locations.

Claims

1. A thread parameter measuring device, characterized in that, comprising a base (1) and a column (18) fixedly connected to the base (1), wherein a rotary clamping unit is further fixedly connected to the base (1), a rotary sliding unit is disposed on the side of the column (18) close to the rotary clamping unit, a visual detection unit is fixedly connected to the side of the column (18) away from the rotary sliding unit, the device further comprises a PLC and a processor, the PLC is electrically connected with the rotary clamping unit, the rotary sliding unit and the visual detection unit, and the processor is electrically connected with the visual detection unit; the rotary clamping unit comprises a rotary table driving motor (20), the rotary table driving motor (20) is fixedly connected with the base (1), the rotary table driving motor (20) is connected with a rotary table reducer (19) through a shaft, and the rotary table reducer (19) is connected with a pneumatic three-jaw chuck (2) through a shaft; the rotary sliding unit comprises a pair of guide rails (13), the pair of guide rails (13) are fixedly connected to the side of the column (18) close to the pneumatic three-jaw chuck (2), each guide rail (13) is slidably connected with a sliding block (21), the sliding block (21) is fixedly connected with a connecting plate (11), the connecting plate (11) is fixedly connected with a live center support (9), the live center support (9) is provided with a through hole coinciding with the axis of the pneumatic three-jaw chuck (2), a sleeve (10) penetrates through the through hole of the live center support (9), and the end of the sleeve (10) close to the pneumatic three-jaw chuck (2) is connected with a live center (8); the visual detection unit comprises a linear module (14), the linear module (14) is fixedly connected to the side of the column (18) away from the pneumatic three-jaw chuck (2), the end of the linear module (14) close to the top end of the column (18) is connected with a module driving motor (12) through a shaft, a rotary table sliding block (22) is slidably connected to the slide rail of the linear module (14), the rotary table sliding block (22) is connected with a rotary table connecting plate (23) through bolts, an electric rotary table (15) is fixedly connected to the rotary table connecting plate (23), the rotating shaft of the electric rotary table (15) is fixedly connected with a rotary table turntable (24), the rotary table turntable (24) is fixedly connected with a visual detection support (7) through bolts, the cross section of the visual detection support (7) is in a "几" shape, two ends of the detection support (7) are respectively and fixedly connected with a camera support (6) and a light source support (16), the camera support (6) and the light source support (16) are provided with through holes, the camera support (6) and the light source support (16) are respectively provided with a camera (4) and a light source (17), and a lens (5) is mounted on the camera (4).

2. The thread parameter measuring device according to claim 1, characterized in that, the axes of the through holes of the camera support (6) and the light source support (16) are on the same plane as the axis of the live center (8).

3. A method for measuring thread parameters using the thread parameter measuring device as described in claim 2, characterized in that, specifically comprising the following steps: S1: Clamp the workpiece (3) to be tested; S2: Perform initial image acquisition; S3: Perform image acquisition through an adaptive helix angle search compensation algorithm based on the thread profile angle; S4: Determine the thread type based on the acquired image; S5: Move the camera (4) to different measurement positions for acquisition; S6: Perform measurement and recording on the images acquired at different positions.

4. The method for measuring thread parameters according to claim 3, characterized in that, The specific process of S1 is as follows: The pneumatic three-jaw chuck (2) holds one end of the workpiece (3) to be tested, and the connecting plate (11) is slid to adjust the height of the rotating center (8) so as to fix the other end of the workpiece (3).

5. The method for measuring thread parameters according to claim 4, characterized in that, The specific process of S2 is as follows: By controlling the linear module (14) with PLC, the vision inspection bracket (7) connected to the linear module (14) is moved to the initial position, and the image of the workpiece (3) to be tested is initially acquired by the camera.

6. The method for measuring thread parameters according to claim 5, characterized in that, The specific process of S3 is as follows: S301: The camera (4) is rotated to a preset image acquisition angle by controlling the electric rotary table (15) through PLC to acquire images. The preset image acquisition angle is set manually on the processor. The setting is based on the fact that the line connecting the camera and the light source is perpendicular to the axis of the rotary tip (8). S302: Based on the image, calculate the tooth profile angle and record the tooth profile angle and its corresponding camera rotation angle; S303: Determine whether the number of image acquisitions has reached the preset number, usually set to 5-10 times. If not, rotate the camera shooting angle according to the preset large step angle and return to S302. The preset large step angle is preset to 1° on the processor. This value is modified by the user. The modification is based on 0.5-1 times the helix angle of the thread to be tested. If the number of acquisitions has been reached, proceed to the next step. S304: Determine the trend of the tooth angle change to ensure that the camera can capture the maximum tooth angle during the rotation process; if the angle increases from small to large, adjust the rotation direction of the camera angle adjustment and adjust the camera angle in the opposite direction; if the angle decreases from large to small, the camera rotation direction remains unchanged; if there is a trend of change from small to large and then back to small, that is, the maximum value of the tooth angle appears, then proceed to step S307. S305: Acquire images, then calculate the tooth profile angle and record the tooth profile angle and its corresponding camera rotation angle; S306: Determine if the tooth angle change trend reaches a maximum point. If not, continue rotating the camera angle according to the set large increment angle and move to S305; if a maximum point appears, proceed to the next step. S307: Rotate the camera to the camera rotation angle corresponding to the maximum value of the tooth angle in S306, then reduce it by five degrees, and start searching for the maximum tooth angle from one side of the maximum tooth angle; S308: Acquire images, calculate tooth profile angles, and record tooth profile angles and their corresponding camera rotation angles; S309: Determine whether the trend of the tooth angle change has reached a maximum value. If not, continue to rotate the camera angle according to the preset small increment angle and return to S308. The preset small increment angle is preset to 0.05° on the processor. This value is modified by the user. The modification basis is set to 0.01-0.05 times the helix angle of the thread to be tested. Continue to rotate the camera angle and return to S308. If a maximum value is found, proceed to S4.

Images