Method for identifying dead head of pressed ball blank and measuring diameter of pressed ball blank

Abstract

The invention belongs to the technical field of measurement, and particularly relates to a pressed ball blank riser recognition and diameter measurement method. The industrial camera is installed on the camera support, the rotating motor is installed on the support, a ball blank to be judged is placed on a platform of the rotating motor, the rotating motor starts to rotate and triggers the industrial camera, the industrial camera scans the outer contour of the ball blank after the rotating motor rotates by a circle, and 36 projection pictures are presented on the imaging plate. The method comprises the following steps: carrying out feature recognition on a picture contour, recognizing a curvature radius change point, recognizing a riser position, measuring the length of the riser and the distance between the riser and an equator line, and finally, obtaining a pose of a sphere through length interval judgment and a scanning result, so as to calculate a compensation angle and realize straightening of the sphere riser. The problem of manual recognition in the production line machining process is solved, and production efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of measurement, and particularly relates to a method for identifying the riser of a pressed spherical blank and measuring its diameter. Background Art

[0002] The spherical fuel element of the high-temperature gas-cooled reactor is to press the material into a spherical blank with a certain strength through a silica gel mold. After pressing, the graphite spherical blank needs to be turned on a lathe, and then processed into a graphite sphere with a smooth surface and a diameter of (59.6 - 60.2) mm. When the turning chuck of the lathe holds the graphite spherical blank, the spherical blank must be in a state where the center line of the riser coincides with the main axis of the lathe. Since the spatial pose of the spherical blank is random when it comes in, it is necessary to use the method of visual judgment + robot to adjust the pose of the spherical blank to a state where the riser faces outward and the center line is parallel to the main axis of the lathe. In addition, it is also necessary to measure the diameter of the product, that is, the major axis diameter and the minor axis diameter. If the diameter detection is out of tolerance, it will be directly rejected. At present, the production is in the engineering stage. There is no standard equipment and mature method for identifying the riser, and all are identified and judged manually by eyes, resulting in low turning efficiency. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for identifying the riser of a pressed spherical blank and measuring its diameter, to solve the problem of manual identification in the production line processing, and to improve production efficiency.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A method for identifying the riser of a pressed spherical blank and measuring its diameter. An industrial camera is installed on a camera support, a rotating motor is installed on the support, the spherical blank to be judged is placed on the platform of the rotating motor, the rotating motor starts to rotate and triggers the industrial camera. When the rotating motor rotates one circle, the industrial camera scans out the outer contour of the spherical blank, and 36 projection images are presented on the imaging plate. Feature recognition is performed on the image contour, the points with changing curvature radius are recognized, the position of the riser is recognized, and the length of the riser and the distance between the riser and the equator line are measured. Finally, through the length interval judgment, the pose of the sphere is obtained from the scanning result, and the compensation angle is calculated to realize the alignment of the riser of the sphere.

[0006] The industrial camera is a laser line scan 3D camera.

[0007] Riser: A circular convex feature generated by the accumulation of materials at the joint of the top cover of the pressing mold and the feeding port of the upper half mold during the pressing process.

[0008] Equator line: An annular convex feature generated by the accumulation of materials at the joint of the upper half mold and the lower half mold of the pressing mold during the pressing process.

[0009] The beneficial effects obtained by the present invention are as follows:

[0010] The feature recognition process and method for the lower spherical blank of spherical fuel elements mainly include feature recognition, selection of difference methods, etc. The diameter measurement process and method for the lower spherical blank of spherical fuel elements. The automatic correction of the position of the spherical blank is completed, and the placement accuracy of the spherical blank is improved. The production efficiency meets the requirements of industrial production. The recognition of the riser feature of the spherical blank and the diameter measurement are realized, meeting the industrial production requirements of the production line. Description of the Drawings

[0011] Figure 1 It is a schematic diagram of the riser recognition device;

[0012] Figure 2 It is the recognition image;

[0013] Figure 3 It is the flow chart of the present invention;

[0014] In the figure: 1-1 industrial camera; 1-2 camera support; 1-3 rotating motor; 1-4 support; 1-5 imaging plate. 2-1 riser; 2-2 equator line. Detailed Embodiment

[0015] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0016] The method of the present invention is as follows:

[0017] The industrial camera 1-1 is installed on the camera support 1-2 and can detect whether there is a sphere. When the robot places the sphere into the work station, the rotating motor 1-3 starts to rotate and triggers the industrial camera 1-1. When the rotating motor 1-3 rotates one circle, the outer contour of the whole sphere will be scanned. The rotating motor 1-3 is installed on the support 1-4. When it is to be determined that the spherical blank is placed on the platform of the rotating motor 1-3, through the rotation of the rotating motor 1-3, the industrial camera 1-1 will present 36 projection images on the imaging plate 1-5. Feature recognition is performed on the contour of the imaging image, the points where the radius of curvature changes are recognized, the length of the riser 2-1 and the distance between the riser 2-1 and the equator line 2-2 are measured. Finally, through the judgment of the length interval, the pose of the sphere is obtained from the scanning result, and then the compensation angle is calculated to realize the alignment of the riser of the sphere and the position of the riser 2-1 is recognized.

[0018] The method of recognizing the equator line + riser has relatively high feasibility and can determine the pose of the riser. According to this design, the working process of the equipment should be: the robot clamps the graphite spherical blank and places it on a tray driven by a servo motor, and the position of the riser is determined by imaging with a vision camera. Through the algorithm, the compensation of the servo motor (rotation around the Z axis), the rotation mechanism (rotation around the X axis) and the compensation angle of the robot (comprehensive compensation) are calculated, and finally the sphere is aligned.

[0019] Riser positioning algorithm flow: The ball seat mechanism rotates the sphere, uses a laser line scan 3D camera to obtain the 3D point cloud data of the sphere, and performs preprocessing. Find the riser position in the point cloud data, and calculate the position of the riser in the X and Y directions. If the riser position cannot be located, the ball seat mechanism rotates the sphere and re-executes the first step. Adjust the riser angle so that the sphere is perpendicular to the camera's shooting direction. The ball seat mechanism rotates the sphere, uses a laser line scan 3D camera to obtain the 3D point cloud data of the sphere, and the diameters of both sides of the riser can be measured. Convert the coordinate data of the machine number and control the robot to perform the clamping and unloading operation. The robot adjusts the angle to place the ball blank in the specified position.

[0020] Diameter measurement process: Using the height measurement function of the 3D laser line scan camera, the 3D camera will be calibrated horizontally before positioning the riser. After finding the reference horizontal plane of the 3D camera, the radius of the sphere can be measured.

[0021] The method of identifying the riser of the ball billet and measuring its diameter is similar to the current fruit segmentation and fruit feature recognition. First, the characteristics of each type of fruit need to be analyzed, and then information collection is completed through image acquisition. The image is processed by grayscale, smoothing, tilt correction, etc. to complete information conversion. Then, the recognition and screening technical route is designed based on the analyzed characteristics. Finally, the communication grasping device grasps according to the position of the recognized features.

[0022] Riser: A circular raised feature produced by the material accumulated at the junction of the top cover of the pressing die and the feeding port of the upper die during the pressing process. Equator: A circular raised feature produced by the material accumulated at the junction of the upper and lower die during the pressing process.

Claims

1. A method for identifying the riser of a pressed billet and measuring its diameter, characterized in that: An industrial camera is installed on the camera support, and a rotating motor is installed on the support. The billet to be judged is placed on the platform of the rotating motor. The rotating motor starts to rotate and triggers the industrial camera. When the rotating motor rotates one circle, the industrial camera scans the outer contour of the billet, and 36 projection images are presented on the imaging plate. Feature recognition is performed on the image contour, the points with changing curvature radius are recognized, the riser position is identified, the riser length and the distance between the riser and the equator line are measured. Finally, through the judgment of the length interval, the pose of the sphere is obtained from the scanning result, and the compensation angle is calculated to achieve the alignment of the sphere riser.

2. The method for identifying the riser of a pressed billet and measuring its diameter according to claim 1, characterized in that: The industrial camera is a laser line-scanning 3D camera.

3. The method for identifying the riser of a pressed billet and measuring its diameter according to claim 1, characterized in that: Riser: A circular convex feature generated by the accumulated material at the joint of the top cover of the pressing die and the feeding port of the upper half die during the pressing process.

4. The method for identifying the riser of a pressed billet and measuring its diameter according to claim 1, characterized in that: Equator line: An annular convex feature generated by the accumulated material at the joint of the upper half die and the lower half die of the pressing die during the pressing process.

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