Measuring device

Abstract

The embodiment of the utility model provides a measuring device, and relates to the field of dimension measurement. The rotating device is arranged on the rack; the moving device is connected with the rotating device; the image acquisition device is connected with the moving device, the rotating device is used for driving the moving device to rotate around the axis perpendicular to the detection plane, and the moving device is used for driving the image acquisition device to move in the direction perpendicular to the axis in the detection plane. According to the utility model, the problem that the measurement is complicated and time-consuming in the prior art is solved, so that the effects of simplifying the measurement method, improving the measurement efficiency and shortening the measurement time are achieved.

Description

Technical Field

[0001] The embodiment of the utility model relates to the field of dimension measurement, and in particular to a measuring device. Background Art

[0002] Large parts are generally provided with multiple holes. When processing or installing large parts, workers are generally required to use vernier calipers to measure the size of each hole and the distance between adjacent holes, which makes the measurement more complicated and time-consuming.

[0003] Currently, no effective solution has been proposed for the above-mentioned problems existing in the related technologies. Utility Model Content

[0004] The embodiment of the utility model provides a measuring device to at least solve the problem of complicated and time-consuming measurement in the related art.

[0005] According to one embodiment of the present invention, a measuring device is provided, comprising:

[0006] frame;

[0007] A rotating device, wherein the rotating device is arranged on the frame;

[0008] A moving device, the moving device is connected to the rotating device;

[0009] The image acquisition device is connected to the moving device, the rotating device is used to drive the moving device to rotate around an axis perpendicular to the detection plane, and the moving device is used to drive the image acquisition device to move in the detection plane along a direction perpendicular to the axis.

[0010] In an exemplary embodiment, the rotating device includes a first stepper motor, the first stepper motor is arranged on the frame, and the main shaft of the first stepper motor is drivingly connected to the moving device.

[0011] In an exemplary embodiment, the rotating device further comprises a first detecting device, and the first detecting device is configured to detect the rotation angle of the first stepper motor main shaft.

[0012] In an exemplary embodiment, the first detection device comprises an encoder.

[0013] In an exemplary embodiment, the frame includes an annular slide rail, and the moving device cooperates with the annular slide rail so that the moving device rotates around an axis perpendicular to the detection plane.

[0014] In an exemplary embodiment, the mobile device comprises:

[0015] A mounting frame connected to the rotating device;

[0016] A linear drive device is arranged on the mounting frame, the linear drive device is connected to the image acquisition device, and the linear drive device is used to drive the image acquisition device to move in the detection plane along a direction perpendicular to the axis.

[0017] In an exemplary embodiment, the linear drive device includes a second stepper motor, a lead screw and a drive nut, the lead screw is rotatably arranged on the mounting frame, the second stepper motor is transmission-connected to the lead screw, the nut cooperates with the lead screw, and the image acquisition device is connected to the nut.

[0018] In an exemplary embodiment, the moving device further comprises a second detection device, and the second detection device is used to detect a distance moved by the image acquisition device in the detection plane along a direction perpendicular to the axis.

[0019] In an exemplary embodiment, the second detection device includes a grating ruler, and the grating ruler includes a scale grating and a grating reading head. The scale grating is arranged on the mounting frame, and the grating reading head is connected to the image acquisition device.

[0020] In an exemplary embodiment, the measuring device further comprises a control device, and the control device is connected to the rotating device, the moving device and the image acquisition device.

[0021] With the measuring device provided in the embodiment of the present application, a rotating device is arranged on a frame, a moving device is connected to the rotating device, and an image acquisition device is connected to the moving device. The rotating device is used to drive the moving device and the image acquisition device to rotate around an axis perpendicular to the detection plane, and the moving device is used to drive the image acquisition device to move in a direction perpendicular to the axis within the detection plane to adjust the position of the image acquisition device. The image acquisition device acquires an image of the measured part, and then the size of the hole and the hole bridge distance on the measured part can be obtained based on the image, thereby simplifying the measurement method, improving the measurement efficiency, and shortening the measurement time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of a measuring device according to an embodiment of the utility model;

[0023] Figure 2 is a schematic diagram of a workpiece to be tested according to an embodiment of the utility model;

[0024] Figure 3 It is a measurement flow chart of the measuring device according to an embodiment of the utility model;

[0025] Figure 4 It is a schematic diagram of a measuring device according to a specific embodiment of the utility model.

[0026] Explanation of reference numerals: 102: frame; 104: rotating device; 106: moving device; 108: image acquisition device; 110: control device. DETAILED DESCRIPTION

[0027] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0029] As the core components of large-scale high-end equipment, large precision parts account for an increasing proportion. There are many problems in the processing and measurement of high-precision large parts. At present, the processing difficulties of high-precision large parts are solved by the more mature application of large machine tools. However, since the geometric accuracy of large core parts directly affects the assembly accuracy of large equipment, and due to the structural and volume limitations of large core parts themselves, the applicability of high-precision general automated measurement equipment is not strong, making the measurement of large parts a common problem faced by the industry. The qualification measurement of large parts currently relies mainly on manual measurement. Since manual measurement is subjective and the measurement of large parts often requires a longer measurement cycle, the low precision and low efficiency of manual measurement methods have become one of the key factors hindering the high-precision and high-efficiency measurement of large parts. This directly affects the delivery and assembly of large equipment. At the same time, some large parts, as core components of high-end equipment, require special structures and shapes, which are not convenient for manual entry, and thus cannot be measured manually. With the advancement of science and technology and the urgent needs of large high-end equipment manufacturing companies, a large number of general instruments and methods suitable for geometric measurement of large parts have developed rapidly. For example, mobile coordinate measurement systems represented by laser trackers; fixed coordinate measurement systems represented by three-coordinate measuring machines; scanning measurement systems represented by laser radars, etc. The measurement efficiency and accuracy of high-precision general-purpose automated measuring instruments are inversely proportional to the size and complexity of large parts to be measured. In addition, the on-site measurement requirements of some large parts make fixed measurement systems "daunting", and the high-precision measurement of surface morphology makes scanning measurement systems represented by laser radars "difficult to take on the task". For example, the tube sheet, a key pressure component of a large heat exchanger as a key equipment in a large boiler plant, is a typical representative. The measurement requirements of large parts such as tube sheets are usually: thousands to tens of thousands of deep holes are arranged on a cylindrical plane with a diameter of 2 to 5 meters, requiring efficient and high-precision on-site measurement of the aperture and hole bridge distance of the deep holes of the tube sheet. If manual measurement is used, it will take about seven days for two people to measure at the same time.

[0030] In view of the above problems existing in the related art, the following embodiments are proposed.

[0031] The embodiment of the present application provides a measuring device, which can be used to measure a hole system on a part. For example, the part may include a large tube sheet, etc. The tube sheet includes a tube body and a plurality of holes arranged in the tube body, and the plurality of holes constitute a hole system. When the part is processed or installed, the diameter of each hole and the hole bridge distance between adjacent holes are measured by the measuring device.

[0032] The schematic diagram of the measuring device in the embodiment of the present application can be found in the attached Figure 1 ,like Figure 1As shown, the device includes a frame 102, which serves as the basis of the measuring device and is used to carry other components in the measuring device. The embodiment of the present application does not limit the specific structure of the frame 102. For example, the frame 102 may include four first brackets located in the same preset plane, and the four first brackets extend in the preset plane. The first brackets are connected at one end close to each other in the preset plane to achieve fixation between the first brackets. The frame 102 also includes a second bracket extending perpendicular to the preset plane, and there are four second brackets, and one end of each second bracket is connected to a first bracket. Each first bracket and the second bracket are arranged to form a receiving cavity, and at least part of the parts to be detected can be placed in the receiving cavity to facilitate the detection of the parts.

[0033] The measuring device also includes a rotating device 104, a moving device 106 and an image acquisition device 108. The rotating device 104 is arranged on the frame 102, the moving device 106 is connected to the rotating device 104, and the image acquisition device 108 is connected to the moving device 106; that is, the image acquisition device 108 is connected to the frame 102 through the moving device 106 and the rotating device 104.

[0034] Among them, the rotating device 104 is used to drive the moving device 106 to rotate around an axis perpendicular to the detection plane, and the moving device 106 is used to drive the image acquisition device 108 to move in the detection plane along a direction perpendicular to the axis. When the rotating device 104 drives the moving device 106 to rotate, it also drives the image acquisition device 108 to rotate; the position of the image acquisition device 108 in the detection plane can be adjusted by the rotating device 104 and the moving device 106 to measure the corresponding position of the detected part.

[0035] It is understandable that the detection plane may be a plane facing the detected part, and through the cooperation of the rotating device 104 and the moving device 106 , the image acquisition device 108 may be aligned with any position in the detection plane.

[0036] In the above implementation, the image acquisition device 108 may include a CCD image sensor, a CMOS image sensor, a camera, or other device capable of acquiring images. The embodiment of the present application does not limit the image acquisition device 108.

[0037] In the embodiment of the present application, the measuring device also includes a control device 110, which is connected to the rotating device 104, the moving device 106 and the image acquisition device 108. The control device 110 can adjust the position of the image acquisition device 108 by controlling the rotating device 104 and the moving device 106. The image acquisition device 108 sends the acquired image to the control device 110, and the control device 110 can obtain the size of the hole on the part (such as the hole diameter and the hole bridge distance, etc.) according to the image.

[0038] In the above embodiment, the measuring object of the measuring device, i.e., the schematic diagram of the workpiece to be measured can be found in the attached Figure 2 ,like Figure 2 As shown, the measuring device can be used to measure the hole system of large hole system feature workpieces represented by large tube sheets, and the main research content is the high-precision and high-efficiency measurement of the hole diameter and hole bridge distance of the above hole system feature workpieces.

[0039] In the above embodiment, when the measuring device is used to measure the workpiece to be measured, the image acquisition device 108 can be first calibrated for the instrument zero point, that is, the optical axis of the camera in the image acquisition device 108 coincides with the rotation axis of the rotating device 104. There is a certain deviation between the actual optical axis position of the camera and the theoretical optical axis position. The actual optical axis position of the camera can be determined by the camera calibration method and then the instrument zero point can be calibrated. When measuring the hole system of a single image, the local measurement image obtained by the camera is a hole system picture, which contains more interference. The image extraction method can be used to obtain the complete image of a single hole and complete the measurement requirements of high-precision aperture and hole bridge distance. In order to measure the hole bridge distance of two holes in different local measurement images, it is necessary to obtain the coordinate positions of the two holes. In order to correct the operating error of the mobile device 106, it seems easy to use image stitching to complete the scanning work of the entire measurement workpiece.

[0040] During the test, the workpiece to be measured can be placed on the measuring platform, or the measuring device can be placed on the placement platform, with the workpiece to be measured on one side of the placement platform. That is, when the workpiece to be measured is convenient to move, the workpiece to be measured can be placed on the measuring platform of the measuring device. When the workpiece to be measured is not convenient to move, the measuring device can be moved and placed on the placement platform to measure the workpiece to be measured. During the measurement, the scanning parameters can be set by the system, such as the control device 110, and the motor can be controlled to drive the camera to scan the surface hole system of the workpiece to be measured, and the collected image can be output to the system control module (corresponding to the control device 110) for subsequent image processing. Among them, the image processing can include pre-processing edge extraction, fitting circle to measure the center coordinates and aperture of the hole system, and image stitching to obtain the complete surface hole system of the workpiece.

[0041] Figure 3 is a measurement flow chart of the measuring device according to an embodiment of the utility model, such as Figure 3As shown in the figure, the process includes: camera calibration and instrument zero point calibration, scanning the local hole system image of the workpiece to be measured, processing the local hole system acquisition image of the workpiece to be measured (which has been dedistorted), firstly using Gaussian filtering and Canny method to extract the edge features of the hole system, and then extracting a single hole image to be measured based on the Hough circle detection method to reduce the influence of "false" edges on the measurement accuracy, and then using the optimized least squares method to complete the high-precision measurement of a single hole, and finally, each single hole sub-image is inversely transformed into the original image, and the template matching method is used to complete the splicing of the local acquisition image of the workpiece to be measured.

[0042] The measuring device provided in the embodiment of the present application comprises a rotating device disposed on a frame, a moving device connected to the rotating device, and an image acquisition device connected to the moving device. The rotating device is used to drive the moving device and the image acquisition device to rotate around an axis perpendicular to a detection plane, and the moving device is used to drive the image acquisition device to move in a direction perpendicular to the axis within the detection plane to adjust the position of the image acquisition device. The image acquisition device acquires an image of the measured part, and then the size of the hole and the hole bridge distance on the measured part can be obtained based on the image, thereby simplifying the measurement method, improving the measurement efficiency, and thereby shortening the measurement time.

[0043] In an exemplary embodiment, the rotating device 104 includes a first stepper motor, which is disposed on the frame 102 , and a main shaft of the first stepper motor is drivingly connected to the moving device 106 .

[0044] Exemplarily, the first stepper motor can be arranged at a position where the first brackets are close to each other, and the main shaft of the first stepper motor is connected to the mobile device 106. When the first stepper motor is working, it can drive the mobile device 106 and the image acquisition device 108 to rotate.

[0045] Through the above arrangement, the first stepper motor drives the moving device 106 to rotate, the structure is simple, and the rotation angle of the moving device 106 can be accurately controlled.

[0046] In an exemplary embodiment, the rotating device 104 further includes a first detection device, which is configured to detect the rotation angle of the first stepper motor main shaft. In this way, the rotation angles of the moving device 106 and the image acquisition device 108 can be accurately controlled.

[0047] Exemplarily, the first detection device may include an encoder, which may be connected to the main shaft of the first stepper motor to detect the rotation angle of the main shaft of the first stepper motor. The encoder may be a rotary encoder.

[0048] In an exemplary embodiment, the frame 102 includes an annular slide rail, and the mobile device 106 cooperates with the annular slide rail so that the mobile device 106 rotates around an axis perpendicular to the detection plane. In this way, the mobile device 106 can be connected to the frame 102 through the annular slide rail, and the mobile device 106 is allowed to rotate under the drive of the rotating device 104.

[0049] Exemplarily, a slide tube may be provided on the mobile device 106, the slide tube is sleeved on the annular slide rail, and the slide tube is slidably connected to the annular slide rail. In other implementations, a first annular slideway is provided on the inner wall (the side wall close to the center of the circle) of the annular slide rail, and a second annular slideway is provided on the outer wall (the side wall away from the center of the circle) of the annular slide rail. Accordingly, a first slider and a second slider are provided on the mobile device 106, the first slider is slidably disposed in the first slideway, and the second slider is slidably disposed in the second slideway.

[0050] In the above implementation, the main shaft of the first stepper motor can be directly connected to the mobile device 106 to drive the mobile device 106 to rotate; illustratively, the first stepper motor can be connected to the mobile device 106 through a coupling. In other implementations, the first stepper motor and the mobile device 106 can also be connected through a gear mechanism, and the speed of the mobile device 106 can be adjusted by properly setting the transmission ratio of the gear mechanism.

[0051] In an exemplary embodiment, the moving device 106 includes: a mounting frame and a linear drive device, the mounting frame is connected to the rotating device 104; the linear drive device is arranged on the mounting frame, the linear drive device is connected to the image acquisition device 108, and the linear drive device is used to drive the image acquisition device 108 to move in a direction perpendicular to the axis within the detection plane.

[0052] Exemplarily, the linear drive device may include a rack disposed on a mounting frame and a second stepper motor connected to the image acquisition device 108. A gear meshing with the rack is disposed on the main shaft of the second stepper motor. When the second stepper motor is working, the drive gear rotates, thereby driving the image acquisition device 108 to move.

[0053] In an exemplary embodiment, the linear drive device includes a second stepper motor, a lead screw and a driving nut, the lead screw is rotatably arranged on a mounting frame, the second stepper motor is drivingly connected to the lead screw, the nut cooperates with the lead screw, and the image acquisition device 108 is connected to the nut. The image acquisition device 108 is driven to move by the cooperation of the lead screw and the nut, and the driving accuracy is high, which can improve the position accuracy of the image acquisition device 108.

[0054] In an exemplary embodiment, the moving device 106 further includes a second detection device, which is used to detect the distance that the image acquisition device 108 moves in the detection plane along a direction perpendicular to the axis. In this way, the second detection device can detect the distance that the image acquisition device 108 moves in the detection plane along a direction perpendicular to the axis, thereby improving the position accuracy of the image acquisition device 108.

[0055] Exemplarily, the second detection device includes a grating ruler, the grating ruler includes a scale grating and a grating reading head, the scale grating is arranged on the mounting frame, and the grating reading head is connected to the image acquisition device 108. The moving distance of the image acquisition device 108 is measured by the grating ruler, the structure is simple, and the detection accuracy is high.

[0056] It can be understood that the embodiment of the present application does not limit the second detection device, as long as it can detect the distance moved by the image acquisition device 108; illustratively, the second detection device may include a laser emitting device and a laser receiving device, the laser emitting device may be arranged on a mounting frame, and the laser receiving device is arranged on the image acquisition device 108; the laser emitting device is used to emit a detection laser beam to the image acquisition device 108, and the position of the image acquisition device 108 can be determined according to the time interval between the laser emitting device emitting the detection laser beam and the laser receiving device receiving the detection laser.

[0057] Figure 4 Schematic diagram of a measuring device according to a specific embodiment of the utility model, such as Figure 4 As shown, the device includes: a visual measurement module (corresponding to the above-mentioned image acquisition module), a linear motion module (corresponding to the above-mentioned moving device 106), a rotational motion module (corresponding to the above-mentioned rotating device 104) and a system control module (corresponding to the above-mentioned control device 110).

[0058] Visual measurement module: A monocular CCD array can be used as an image acquisition component. Its functions include image acquisition at a local position on the workpiece surface, preprocessing the acquired image, and measuring the center coordinates and aperture of the hole system at the local position.

[0059] Linear motion module: It can be driven by a worm gear stepper motor and the linear motion position of the camera can be obtained through a grating ruler;

[0060] Rotational motion module: It can be driven by a worm gear stepper motor and output the camera rotation position through a rotary encoder;

[0061] The visual measurement module is moved to the specified position through linear motion and rotational motion, and its motion accuracy is guaranteed by the control accuracy of the grating ruler and the rotary encoder respectively;

[0062] System control module: It can analyze the data of the visual measurement module, give the current local measurement status, and use the data of the real-time position measurement module to give the motion parameters, and control the motion module to move to the specified position.

[0063] The system uses a visual measurement module to measure the current hole system data, gratings and rotary encoders to provide current position information, and the system control module controls the motion module to complete global scanning.

[0064] In the aforementioned embodiment, the rotating device 104 drives the moving device 106 and the image acquisition device 108 to rotate around an axis perpendicular to the detection plane, and the moving device 106 drives the image acquisition device 108 to move in the detection plane in a direction perpendicular to the axis, that is, a polar coordinate scanning measurement method is adopted, which can effectively solve the problem that the camera field of view is much smaller than the size of the large workpiece to be measured, the measuring surface is too small, and the measurement efficiency is low.

[0065] The entire workpiece surface is scanned by combining a rotary motion module and a linear motion module. The advantages of this solution include:

[0066] (1) The measurement of circular workpieces reduces redundant scanning data compared to rectangular coordinate system measurement and improves measurement efficiency;

[0067] (2) By adding linear modules and camera modules at different angles, it is not easy for the two linear motion modules to interfere with each other;

[0068] (3) By modifying the support frame, it can be applied to the measurement of large cylindrical workpieces of different sizes.

[0069] In the above-mentioned embodiment, the position information of all holes of the workpiece to be measured is collected by the image stitching method. First, the Hough circle detection method is used to extract the image of a single hole to be measured to reduce the influence of the "false" edge on the measurement accuracy. Secondly, the optimized least squares method is used to complete the high-precision measurement of a single hole, and finally each single hole sub-image is inversely transformed into the original image. Finally, the template matching method is used to complete the stitching of the local acquisition images of the workpiece to be measured. Thus, the hole distance of any two holes can be obtained. The positioning accuracy mainly depends on the accuracy of the image stitching algorithm. Since the stitching of all hole systems of the workpiece must be completed first, the efficiency of measuring the distance between two non-adjacent holes is not high, but the measurement efficiency is significantly improved after all the measured local images are stitched. In order to comprehensively improve the measurement accuracy and efficiency of the distance between two holes of the instrument at different local measurement positions, this proposal uses a grating and a rotary encoder to obtain the precise position information of the camera for a few cases where the stitching of all hole systems of the workpiece is not completed, and the camera is only responsible for the measurement of the coordinates of the center of the local hole circle.

[0070] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, the utility model may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A measuring device, characterized in that: include: frame; A rotating device, wherein the rotating device is arranged on the frame; A moving device, the moving device is connected to the rotating device; The image acquisition device is connected to the moving device, the rotating device is used to drive the moving device to rotate around an axis perpendicular to the detection plane, and the moving device is used to drive the image acquisition device to move in the detection plane along a direction perpendicular to the axis.

2. The measuring device according to claim 1, characterized in that The rotating device comprises a first stepper motor, the first stepper motor is arranged on the frame, and the main shaft of the first stepper motor is transmission-connected with the moving device.

3. The measuring device according to claim 2, characterized in that The rotating device further comprises a first detecting device, wherein the first detecting device is configured to detect a rotation angle of the first stepper motor main shaft.

4. The measuring device according to claim 3, characterized in that The first detection device includes an encoder.

5. The measuring device according to any one of claims 1 to 4, characterized in that: The frame comprises an annular slide rail, and the moving device cooperates with the annular slide rail so that the moving device rotates around an axis perpendicular to the detection plane.

6. The measuring device according to any one of claims 1 to 4, characterized in that: The mobile device comprises: A mounting frame connected to the rotating device; A linear drive device is arranged on the mounting frame, the linear drive device is connected to the image acquisition device, and the linear drive device is used to drive the image acquisition device to move in the detection plane along a direction perpendicular to the axis.

7. The measuring device according to claim 6, characterized in that The linear drive device includes a second stepper motor, a lead screw and a driving nut. The lead screw is rotatably arranged on the mounting frame. The second stepper motor is transmission-connected to the lead screw. The nut cooperates with the lead screw. The image acquisition device is connected to the nut.

8. The measuring device according to claim 6, characterized in that The moving device further comprises a second detection device, and the second detection device is used to detect the distance moved by the image acquisition device in the detection plane along a direction perpendicular to the axis.

9. The measuring device according to claim 8, characterized in that The second detection device includes a grating ruler, and the grating ruler includes a scale grating and a grating reading head. The scale grating is arranged on the mounting frame, and the grating reading head is connected to the image acquisition device.

10. The measuring device according to any one of claims 1 to 4, characterized in that: The measuring device further comprises a control device, and the control device is connected to the rotating device, the moving device and the image acquisition device.

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