Positioning method and device for machine vision assisted numerical control lathe workpiece axis alignment

Abstract

The invention discloses a positioning method and device for machine vision assisted numerical control lathe workpiece axis alignment. The positioning method comprises the steps that pre-clamping and initial positioning are conducted on a to-be-machined part; obtaining point cloud data of the three-dimensional contour of the to-be-machined part through a visual scanning assembly; based on the point cloud data of the three-dimensional contour, the axis position of the to-be-machined part and the deviation value between the axis position and the rotating axis of a main shaft of the numerical control lathe are calculated; and the target clamping position of the to-be-machined part is determined based on the deviation value, so that centering clamping and machining are achieved. The motion path of the visual scanning assembly is accurately controlled, the shaft part can be comprehensively scanned to obtain three-dimensional contour data of the shaft part, the axis line is determined through calculation, then the clamping jaw is accurately adjusted and controlled, the axis line of the part coincides with the axis line of the lathe spindle, centering clamping and driving machining of the part are completed, and the machining efficiency is improved. Unmanned intelligent clamping alignment is achieved, and the part clamping quality and efficiency are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of machining equipment, and particularly to a positioning method and device for aligning the axis of a workpiece on a numerically controlled lathe assisted by machine vision. Background Technique

[0002] As a high-precision, high-efficiency and highly flexible automated machining equipment, numerically controlled lathes are widely used in fields such as aerospace, automotive, electronics, and medical devices. However, when machining shaft parts (shaft blanks or rough-machined parts on numerically controlled lathes), especially for irregular shaft parts such as eccentric structures, the clamping method has a direct impact on machining accuracy and efficiency. Traditional centering clamping methods include self-centering three-jaw chucks, independent four-jaw chucks, two-center clamping, and mandrel clamping, etc. However, the above solutions have the following limitations:

[0003] First, it is difficult to control the clamping force. If the clamping force is too small, the part may slide or fall off, causing vibration and damaging the part and the tool; if the clamping force is too large, the part may deform, damage the surface, and accelerate the wear of the fixture and the machine tool. Second, it is extremely difficult to clamp irregular shaft parts. For irregular shaft parts such as eccentric structures, common clamping methods are difficult to ensure that the rotation center during machining coincides with the spindle axis, thus affecting the clamping efficiency and accuracy. Third, the clamping efficiency is very low. Existing clamping methods require manual adjustment and it is difficult to achieve automation and intelligence. Summary of the Invention

[0004] Embodiments of the present invention provide a positioning method and device for aligning the axis of a workpiece on a numerically controlled lathe assisted by machine vision to solve the technical problems of low clamping efficiency and poor accuracy in machining irregular shaft parts in the prior art.

[0005] In view of the above technical problems, embodiments of the present invention provide a positioning method for aligning the axis of a workpiece on a numerically controlled lathe assisted by machine vision, including:

[0006] Pre-clamp and perform initial positioning on the workpiece to be machined;

[0007] Obtain the point cloud data of the three-dimensional contour of the workpiece to be machined through a vision scanning component;

[0008] Based on the point cloud data of the three-dimensional contour, calculate the axis position of the workpiece to be machined and the deviation value from the spindle rotation axis of the numerically controlled lathe;

[0009] Determine the target clamping position of the workpiece to be machined based on the deviation value to achieve centering clamping and machining.

[0010] Optionally, the pre-clamping and initial positioning of the workpiece to be machined includes:

[0011] Pre - clamp the part to be machined in the servo chuck of the CNC lathe; drive the jaws on the servo chuck to move linearly, so as to make the jaws apply a pre - tightening force to the part to be machined; adjust the rotation of the part to be machined.

[0012] Optionally, obtaining the point cloud data of the three - dimensional contour of the part to be machined through the vision scanning component includes:

[0013] Drive the vision scanning component to move to one side of the part to be machined, and rotate the optical sensor of the vision scanning component to the direction of the part to be machined;

[0014] Adjust the scanning head of the optical sensor to face the part to be machined;

[0015] Drive the optical sensor to move linearly along the axial direction of the part to be machined to scan the contour of the workpiece and obtain the point cloud data of the three - dimensional contour of the part to be machined.

[0016] Optionally, calculating the position of the axis line of the part to be machined and the deviation value from the rotation axis line of the main shaft of the CNC lathe based on the point cloud data of the three - dimensional contour includes:

[0017] Using the coordinate transformation method, determine the coordinates of each point through the scanning path of the optical sensor and the vertical distance between the optical sensor and the part to be machined;

[0018] On each circumferential section, calculate the center coordinates by least - squares fitting;

[0019] Perform least - squares linear fitting on the center coordinates of each section to calculate the position coordinates of the axis line of the part to be machined;

[0020] Compare the position coordinates of the axis line of the part to be machined with the rotation axis line coordinates of the main shaft of the CNC lathe to obtain the deviation value.

[0021] Optionally, determining the target clamping position of the part to be machined based on the deviation value to achieve centering clamping and machining includes:

[0022] According to the deviation value, drive the jaws on the servo chuck to move linearly, and then adjust the position of the part to be machined. When the axis line of the part to be machined coincides with the rotation axis line of the main shaft of the CNC lathe, it is used as the target clamping position, and drive the jaws to apply a pre - tightening force to the part to be machined;

[0023] Adjust the center of the CNC lathe to move to the shaft end of the part to be machined away from the servo chuck to achieve centering clamping of the part to be machined;

[0024] Drive the servo chuck to perform a rotational movement, control the tool rest of the CNC machine tool to rotate to the preset position of the machining tool, and machine the part to be machined.

[0025] The present invention also provides a positioning device for aligning the axis center of a workpiece on a machine vision-assisted numerically controlled lathe, comprising:

[0026] A positioning fixture for pre-clamping and initially positioning the part to be machined;

[0027] A vision scanning assembly mounted on the tool rest of the numerically controlled lathe and arranged on one side of the part to be machined. The vision scanning assembly includes an optical sensor for acquiring point cloud data of the three-dimensional profile of the part to be machined;

[0028] A driving assembly disposed on the base of the numerically controlled lathe for driving the vision scanning assembly to perform a linear motion along the axial direction of the part to be machined;

[0029] A controller communicatively connected to the driving assembly, the vision scanning assembly, and the positioning fixture respectively;

[0030] An upper computer in which a machine-executable program is stored. When the machine-executable program is executed by the controller, it is used to implement the positioning method according to any one of claims 1 to 5;

[0031] A center point disposed on the base and oppositely arranged with the positioning fixture for clamping the shaft end of the part to be machined away from the positioning fixture.

[0032] Optionally, the positioning fixture includes a servo chuck rotatably mounted on the base and at least two jaws slidably mounted on the servo chuck.

[0033] Optionally, the vision scanning assembly includes an optical sensor mounted on the tool rest.

[0034] Optionally, the driving assembly includes a feed base and a driving motor connecting the tool rest, and the driving motor is slidably connected to the feed base.

[0035] The beneficial effects of the present invention are as follows:

[0036] The core of the present invention lies in the ingenious integration of a machine vision component on the tool rest of a numerically controlled lathe, thereby realizing the automated and intelligent clamping and alignment process of a workpiece to be machined (especially shaft parts, particularly complex parts with eccentric structures) before machining. Specifically, this process first relies on precisely controlling the movement path of an optical sensor to conduct a comprehensive and non-blind-spot fine scan of the workpiece to be machined, ensuring the complete acquisition of its three-dimensional contour data. Subsequently, measurement and calculation techniques are used to deeply analyze these three-dimensional data and accurately calculate the position of the axis line of the part. This process takes into account both the overall geometric shape of the workpiece to be machined and its local subtle features, thereby ensuring a very high accuracy of the axis line position. Immediately afterwards, by precisely controlling the clamping action of the servo chuck, the position of the workpiece to be machined is accurately adjusted to ensure that the axis line of the workpiece to be machined perfectly coincides with the axis line of the spindle rotation of the numerically controlled lathe. This not only significantly improves the clamping quality and machining accuracy, but also realizes the intelligent operation without human intervention in the entire clamping process, greatly improving the clamping efficiency and machining quality of the workpiece to be machined, providing a solid technical support for the numerically controlled lathe to achieve high-precision and high-efficiency machining operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 is a flowchart of a positioning method for finding the axis center of a workpiece assisted by machine vision in a numerically controlled lathe according to an embodiment of the present invention;

[0039] Figure 2 is an overall structural diagram of a positioning device for finding the axis center of a workpiece assisted by machine vision in a numerically controlled lathe according to an embodiment of the present invention;

[0040] Figure 3 is a partial structural diagram of a positioning device for finding the axis center of a workpiece assisted by machine vision in a numerically controlled lathe according to another embodiment of the present invention.

[0041] The reference numerals in the specification are as follows:

[0042] 100 - positioning fixture, 110 - servo chuck, 120 - jaw, 200 - vision scanning component, 210 - optical sensor, 300 - drive component, 310 - feed base, 320 - drive motor, 400 - controller, 500 - center, 600 - workpiece to be machined, 700 - tool rest, 800 - base. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection" and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0046] As Figure 1 shown, an embodiment of the present invention provides a positioning method for aligning the axis of a workpiece of a machine vision-assisted numerically controlled lathe, including:

[0047] S10. Pre-clamp and initially position the workpiece 600 to be machined; the step S10 further includes pre-clamping the workpiece 600 to be machined in the servo chuck 110 of the numerically controlled lathe; driving the jaws 120 on the servo chuck 110 to perform a linear motion, so as to drive the jaws 120 to apply a pre-tightening force to the workpiece 600 to be machined; adjusting the rotation of the workpiece 600 to be machined.

[0048] It can be understood that the pre-clamping and initial positioning of the workpiece 600 to be machined is the starting link of the positioning method for aligning the axis of a workpiece of a machine vision-assisted numerically controlled lathe. Its core purpose is to initially fix the workpiece 600 to be machined on the numerically controlled lathe and provide conditions for subsequent scanning operations by slowly rotating. This step ensures that the workpiece 600 to be machined can be stably fixed in the servo chuck 110 in the initial clamping state through the jaws 120, and at the same time avoids damaging the workpiece due to excessive clamping force.

[0049] S20. Obtain the point cloud data of the three-dimensional contour of the part to be machined 600 through the vision scanning component 200. Understandably, use the vision scanning component 200 to comprehensively scan the part to be machined 600 pre-clamped on the numerically controlled lathe to obtain the point cloud data of its three-dimensional contour. The point cloud data is the basis for subsequent calculation of the axis position.

[0050] In one embodiment, the step S20 further includes the following sub-steps:

[0051] S201. Drive the vision scanning component 200 to move to one side of the part to be machined 600, and rotate the optical sensor 210 of the vision scanning component 200 towards the part to be machined 600. This step ensures that the scanning head of the optical sensor 210 is directly aligned with the part to be machined 600. This step ensures that the optical sensor 210 can be aligned with the part to be machined 600.

[0052] S202. Adjust the scanning head of the optical sensor 210 to face the direction of the part to be machined 600. This step ensures that the scanning head of the optical sensor 210 is directly aligned with the part to be machined 600, ensures that the optical sensor 210 is in the best scanning position, and can comprehensively scan the part to be machined 600 from the axial direction, avoiding inaccurate scanning data caused by position deviation.

[0053] S203. Drive the optical sensor 210 to perform a linear motion along the axial direction of the part to be machined 600 to scan the contour of the workpiece and obtain the point cloud data of the three-dimensional contour of the part to be machined 600. This step scans the entire axial contour of the part to be machined 600 through the linear motion of the optical sensor 210 to obtain its accurate point cloud data of the three-dimensional contour. The integrity and accuracy of the point cloud data directly affect the final clamping accuracy and machining quality.

[0054] Understandably, the above steps can quickly and accurately obtain the surface topography data of the part to be machined 600, providing key technical support for realizing automatic and intelligent clamping and alignment.

[0055] S30. Based on the point cloud data of the three-dimensional contour, calculate the axis position of the part to be machined 600 and the deviation value from the spindle rotation axis of the numerically controlled lathe.

[0056] In one embodiment, the step S30 further includes the following sub-steps:

[0057] S301. Using the coordinate transformation method, determine the coordinates of each point based on the scanning path of the optical sensor 210 and the vertical distance between the optical sensor 210 and the part to be machined 600. Understandably, since the optical sensor 210 moves along a specific path during scanning and its relative position with respect to the part to be machined 600 is constantly changing, it is necessary to transform the scanned point cloud data into a unified coordinate system through the coordinate transformation method for subsequent analysis and processing. By considering the scanning path of the optical sensor 210 and its vertical distance from the part, accurately calculate the three-dimensional coordinates of each point in the point cloud data, providing a data basis for the calculation of the axis line.

[0058] S302. On each circumferential section, calculate the center coordinates by least squares fitting. Understandably, by fitting these points using the least squares method, the center coordinates of each circumferential section can be calculated, which helps to eliminate the influence of measurement errors and noise and improve the calculation accuracy of the center coordinates.

[0059] S303. Perform least squares linear fitting on the center coordinates of each section to calculate the position coordinates of the axis line of the part to be machined 600. Understandably, this step takes into account the center coordinates of all sections, so it can more comprehensively reflect the actual position of the axis line of the part to be machined 600.

[0060] S304. Compare the position coordinates of the axis line of the part to be machined 600 with the coordinates of the spindle rotation axis line of the CNC lathe to obtain the deviation value. Understandably, by calculating the deviation value between these two coordinates, the accuracy of the current clamping position of the part to be machined 600 can be quantitatively evaluated, providing a clear basis and direction for the adjustment of the subsequent clamping position.

[0061] S40. Determine the target clamping position of the part to be machined 600 based on the deviation value to achieve centering clamping and machining. The step S40 further includes the following sub-steps:

[0062] In one embodiment, S401: According to the deviation value, drive the jaws 120 on the servo chuck 110 to perform a linear motion, thereby adjusting the position of the part to be machined 600, and taking the coincidence of the axis line of the part to be machined 600 and the rotation axis line of the main shaft of the numerical control lathe as the target clamping position, and driving the jaws 120 to apply a pre-tightening force to the part to be machined 600. Understandably, by controlling the linear motion of the jaws 120 on the servo chuck 110, the position of the part to be machined 600 is accurately adjusted; by continuously adjusting the position of the jaws 120, the axis line of the part to be machined 600 is made to coincide with the rotation axis line of the main shaft of the numerical control lathe, providing a guarantee for improving the machining accuracy; after reaching the target clamping position, driving the jaws 120 to apply an appropriate pre-tightening force to the part to be machined 600 to ensure that the part to be machined 600 will not move due to vibration or external force.

[0063] S402: Adjust the center 500 of the numerical control lathe to move to the shaft end of the part to be machined 600 away from the servo chuck 110 to achieve centering clamping of the part to be machined 600. Understandably, through the combined action of the center 500 and the jaws 120 on the servo chuck 110, centering clamping of the part to be machined 600 is achieved, which can minimize vibration and deviation during the machining process and improve the clamping accuracy.

[0064] S403: Drive the servo chuck 110 to perform a rotational motion, control the tool rest 700 of the numerical control machine tool to rotate to the preset position of the machining tool, and machine the part to be machined 600. Understandably, after the part to be machined 600 is accurately centered and clamped and the tool is positioned, start the machining program of the numerical control machine tool to machine the part to be machined 600.

[0065] In the above embodiments of the present invention, the machine vision component is ingeniously integrated on the tool rest 700 of the numerically controlled lathe, thereby realizing the automatic and intelligent clamping and alignment process of the workpiece 600 to be machined (especially shaft parts, especially complex parts with eccentric structures) before machining. Specifically, this process first relies on precisely controlling the movement path of the optical sensor 210 to finely scan the part in all directions without dead angles, ensuring the complete acquisition of its three-dimensional contour data. Subsequently, measurement and calculation technologies are used to deeply analyze these three-dimensional data and accurately calculate the position of the axis line of the part. This process takes into account both the overall geometric shape of the workpiece 600 to be machined and its local subtle features, thus ensuring a very high accuracy of the axis line position. Immediately afterwards, by precisely controlling the clamping action of the servo chuck 110, the position of the part is accurately adjusted to ensure that the axis line of the part perfectly coincides with the axis line of the spindle rotation of the numerically controlled lathe. This not only significantly improves the clamping quality and machining accuracy, but also realizes the unmanned intelligent operation of the entire clamping process, greatly improving the clamping efficiency and machining quality of the workpiece 600 to be machined, providing a solid technical support for the numerically controlled lathe to achieve high-precision and high-efficiency machining operations.

[0066] In one embodiment, as Figures 2 to 3 shown, the present invention further provides a positioning device for finding the axis center of a workpiece on a numerically controlled lathe assisted by machine vision, including:

[0067] A positioning fixture 100, which is used for pre-clamping and initial positioning of the workpiece 600 to be machined;

[0068] A vision scanning component 200, which is installed on the tool rest 700 of the numerically controlled lathe and arranged on one side of the workpiece 600 to be machined. The vision scanning component 200 includes an optical sensor 210, and the optical sensor 210 is used to obtain the point cloud data of the three-dimensional contour of the workpiece 600 to be machined;

[0069] A driving component 300, which is arranged on the base 800 of the numerically controlled lathe, and the driving component 300 is used to drive the vision scanning component 200 to perform a linear motion along the axial direction of the workpiece 600 to be machined;

[0070] A controller 400, which is respectively communicatively connected to the driving component 300, the vision scanning component 200 and the positioning fixture 100;

[0071] A host computer, in which a machine-executable program is stored. When the machine-executable program is executed by the controller 400, it is used to implement the positioning method according to any one of claims 1 to 5;

[0072] The top center 500 is arranged on the base 800 and is disposed opposite to the positioning fixture 100. The top center 500 is used to clamp the shaft end of the part to be machined 600 away from the positioning fixture 100.

[0073] The optical sensor 210 is used to obtain the point cloud data of the three-dimensional profile of the part to be machined 600. The optical sensor 210 is communicatively connected to the host computer. The host computer sends the point cloud data of the three-dimensional profile to the controller 400, and the controller 400 performs centering clamping and machining on the part to be machined 600 according to the positioning method described above.

[0074] In one embodiment, as Figures 2 to 3 shown, the positioning fixture 100 includes a servo chuck 110 rotatably mounted on the base 800 and at least two jaws 120 slidably mounted on the servo chuck 110. Understandably, the number of jaws 120 can be 4. The 4 jaws 120 are evenly spaced on the servo chuck 110 and can flexibly adapt to shaft parts of different shapes and sizes. The servo chuck 110 is connected to a turntable motor, and the turntable motor is mounted on the main shaft of the servo chuck 110 to drive the servo chuck 110 to perform a rotational movement, which is used for the rotational movement of the part to be machined 600 during the machining of shaft parts, and can achieve precise rotational movement of the part during the machining process and meet the multi-angle machining requirements. In addition, the servo chuck 110 can also be internally provided with a servo system. The servo system includes a servo controller 400 and 4 torque-controlled servo motors. By virtue of the cooperation of the servo controller 400 and the 4 torque-controlled servo motors, the four jaws 120 on the servo chuck 110 are respectively precisely controlled to perform linear movements, not only making the clamping movement accuracy reach an extremely high level, ensuring the precise positioning of the part to be machined 600, but also being able to precisely control the clamping force, avoiding deformation or damage of the part to be machined 600 caused by improper clamping force, and effectively guaranteeing the part machining quality and the stability of clamping.

[0075] In one embodiment, as Figures 2 to 3 shown, the driving assembly 300 includes a feed base 310 and a driving motor 320 connecting the tool rest 700. The driving motor 320 is slidably connected to the feed base 310. Understandably, the feed base 310 is fixedly mounted on the base 800. Multiple slide rails are provided on the feed base 310. The driving motor 320 is connected to the slide rails through sliders. Furthermore, the driving motor 320 can slide on the feed base 310, thereby driving the optical sensor 210 on the vision scanning assembly 200 to run smoothly along a predetermined trajectory, achieving flexible displacement control of the optical sensor 210 in three-dimensional space, ensuring that the scanning trajectory is precisely controllable, and further realizing complete and detailed acquisition of the three-dimensional profile data of different positions of the part, improving the comprehensiveness and accuracy of data acquisition.

[0076] In one embodiment, as Figures 2 to 3 shown, the visual scanning component 200 includes an optical sensor 210 mounted on the tool rest 700. Understandably, the tool rest 700 is mounted on the base 800 and can rotate under the drive of the drive motor 320, so as to flexibly adjust the position of the optical sensor 210 and realize the scanning of the part to be machined 600 from different angles and in all directions.

[0077] In the device of the above embodiment of the present invention, the working process of the device is as follows:

[0078] First, perform the preliminary clamping and pre-tightening of the part to be machined 600. The operator pre-clamps the workpiece to be machined in the servo chuck 110 by visual inspection method, adjusts the servo chuck 110 to an appropriate angle, and the servo motor drives the jaws 120 to perform a linear motion, so that the four jaws 120 simultaneously apply a certain pre-tightening force to the part to be machined 600. After that, start the turntable motor to drive the servo chuck 110 to rotate, so that the part to be machined 600 performs a slow rotational motion to prepare for the subsequent scanning.

[0079] Secondly, perform the three-dimensional contour scanning of the part to be machined 600. Start the optical sensor 210, control the feed base 310 to move so that the tool rest 700 moves to one side of the part to be machined 600, start the drive motor 320 to rotate the optical sensor 210 towards the workpiece direction, and make its scanning head face the part to be machined 600, so as to be able to scan out the complete contour of the part to be machined 600. The operator operates using the numerical control panel provided on the base 800, controls the optical sensor 210 to perform a linear motion along the axial direction of the part to be machined 600, and scans the contour of the part to be machined 600. The optical sensor 210 displays the obtained three-dimensional contour morphology data of the workpiece on the numerical control panel. After the scanning is completed, adjust the feed base 310 to move so that the optical sensor 210 retracts to the safe area to avoid affecting the subsequent machining process.

[0080] Then, perform the calculation of the axis center line position and deviation analysis. Based on the three-dimensional contour point cloud data of the workpiece measured by the optical sensor 210, using the coordinate transformation method, determine the coordinates of each point through the scanning path of the optical sensor 210 and the vertical distance between it and the workpiece. On each circumferential section, the center coordinates are obtained by least squares fitting. Then, perform least squares linear fitting on the center coordinates of each section to calculate the position coordinates of the axis center line. Compare this coordinate with the coordinate of the spindle rotation axis center line of the numerically controlled lathe to obtain the deviation value between the two.

[0081] Finally, precise centering and clamping of the workpiece are carried out according to the calculated deviation value. According to the previously calculated deviation of the axis position coordinates between the workpiece 600 to be machined and the spindle axis of the CNC lathe, the jaws 120 are driven to move linearly by the servo motor again, so that the four jaws 120 respectively move to the positions where the axis of the workpiece 600 to be machined coincides with the rotational axis of the spindle of the CNC lathe. Then, the center point 500 is adjusted to move to the end of the workpiece 600 to be machined to complete the centering and clamping. Next, the servo chuck 110 is driven by the turntable motor to rotate at a high speed, the driving motor 320 is controlled to rotate the tool rest 700 to the position of the required machining tool, and then the part is machined according to the required machining process.

[0082] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A positioning method for finding the axis center of a workpiece on a numerically controlled lathe assisted by machine vision, characterized in that, Including: S10. Pre - clamp and initially position the part to be machined (600); S20. Obtain the point cloud data of the three - dimensional contour of the part to be machined (600) through the vision scanning component (200); S30. Based on the point cloud data of the three - dimensional contour, calculate the position of the axis line of the part to be machined (600) and the deviation value from the rotation axis line of the main shaft of the CNC lathe; S40. Determine the target clamping position of the part to be machined (600) based on the deviation value to achieve centering clamping and machining.

2. The positioning method for workpiece axis alignment of a machine vision-assisted CNC lathe according to claim 1, characterized in that, The step S10 includes: S101. Pre - clamp the part to be machined (600) in the servo chuck (110) of the CNC lathe; drive the jaws (120) on the servo chuck (110) to move linearly, so that the jaws (120) apply a pre - tightening force to the part to be machined (600); adjust the rotation of the part to be machined (600).

3. The positioning method for workpiece axis alignment of a machine vision-assisted CNC lathe according to claim 2, characterized in that, The step S20 includes: S201. Drive the vision scanning component (200) to move to one side of the part to be machined (600), and rotate the optical sensor (210) of the vision scanning component (200) towards the part to be machined (600); S202. Adjust the scanning head of the optical sensor (210) to face the direction of the part to be machined (600); S203. Drive the optical sensor (210) to move linearly along the axial direction of the part to be machined (600) to scan the contour of the workpiece and obtain the point cloud data of the three - dimensional contour of the part to be machined (600).

4. The positioning method for aligning the axis center of a workpiece on a machine vision-assisted numerically controlled lathe according to claim 3, characterized in that, The step S30 includes: S301. Using the coordinate transformation method, determine the coordinates of each point through the scanning path of the optical sensor (210) and the vertical distance between the optical sensor (210) and the part to be machined (600); S302. On each circumferential section, calculate the center coordinates by least - squares fitting; S303. Perform least - squares linear fitting on the center coordinates of each section to calculate the position coordinates of the axis line of the part to be machined (600); S304. Compare the position coordinates of the axis line of the part to be machined (600) with the coordinates of the rotation axis line of the main shaft of the CNC lathe to obtain the deviation value.

5. The positioning method for aligning the axis center of a workpiece on a machine vision-assisted numerically controlled lathe according to claim 4, characterized in that, The step S40 includes: S401. According to the deviation value, drive the jaws (120) on the servo chuck (110) to move linearly, and then adjust the position of the part to be machined (600). When the axis line of the part to be machined (600) coincides with the rotation axis line of the main shaft of the CNC lathe, it is used as the target clamping position, and the jaws (120) apply a pre - tightening force to the part to be machined (600); S402. Adjust the center (500) of the CNC lathe to move to the axial end of the part to be machined (600) far from the servo chuck (110) to achieve centering clamping of the part to be machined (600); S403. Drive the servo chuck (110) to perform a rotational movement, control the tool rest (700) of the CNC machine tool to rotate to the preset position of the machining tool, and machine the part to be machined (600).

6. The positioning device for workpiece axis alignment of a machine vision-assisted CNC lathe according to claim 5, characterized in that, Including: Positioning fixture (100), which is used for pre-clamping and initial positioning of the part to be machined (600); Vision scanning component (200), which is mounted on the tool rest (700) of the CNC lathe and arranged on one side of the part to be machined (600). The vision scanning component (200) includes an optical sensor (210), and the optical sensor (210) is used to obtain the point cloud data of the three-dimensional contour of the part to be machined (600); Drive component (300), which is arranged on the base (800) of the CNC lathe, and the drive component (300) is used to drive the vision scanning component (200) to perform a linear motion along the axial direction of the part to be machined (600); Controller (400), which is communicatively connected to the drive component (300), the vision scanning component (200) and the positioning fixture (100) respectively; Host computer, in which a machine-executable program is stored. When the machine-executable program is executed by the controller (400), it is used to implement the positioning method according to any one of claims 1 to 5; Center (500), which is arranged on the base (800) and is arranged opposite to the positioning fixture (100). The center (500) is used to clamp the shaft end of the part to be machined (600) away from the positioning fixture (100).

7. The positioning device for workpiece axis alignment of a machine vision-assisted CNC lathe according to claim 6, characterized in that, The positioning fixture (100) includes a servo chuck (110) rotatably mounted on the base (800) and at least two jaws (120) slidably mounted on the servo chuck (110).

8. The positioning device for workpiece axis alignment of a machine vision-assisted CNC lathe according to claim 6, characterized in that, The vision scanning component (200) includes an optical sensor (210) mounted on the tool rest (700).

9. The positioning device for aligning the axis center of a workpiece on a machine vision-assisted CNC lathe according to claim 8, characterized in that, The drive component (300) includes a feed base (310) and a drive motor (320) connecting the tool rest (700). The drive motor (320) is slidably connected to the feed base (310).

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