A method and system for contactless detection of the flatness and parallelism of a porcelain shell of an arc-extinguishing chamber

Abstract

The application discloses a method and system for non-contact detection of flatness and parallelism of a porcelain shell of an arc-extinguishing chamber. The method positions the porcelain shell of the arc-extinguishing chamber to be detected in a measurement area of a non-contact laser scanning system, determines a first plane to be detected and a second plane to be detected, calibrates a laser displacement sensor and a two-dimensional moving platform, and establishes a corresponding relationship between a vertical distance and a motion coordinate, obtains a first three-dimensional coordinate set and a second three-dimensional coordinate set through rectangular grid scanning, removes abnormal outliers, and performs least square plane fitting to obtain a first fitting reference plane and a second fitting reference plane, determines flatness errors according to distances of measurement points to corresponding fitting reference planes, determines parallelism errors with the first fitting reference plane as a parallelism evaluation reference, and outputs a detection result.

Description

Technical Field

[0001] This invention belongs to the field of flatness detection technology, specifically relating to a non-contact method and system for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber. Background Technology

[0002] As the insulating outer shell of a vacuum interrupter switch, the ceramic shell of the interrupter needs to have its dimensional and positional dimensions, such as those on its end faces, inspected during production and acceptance. Current inspection methods typically involve using feeler gauges, dial indicators, and other measuring tools on an inspection platform to measure flatness and parallelism. If necessary, a coordinate measuring machine can be used to verify the relevant dimensional and positional dimensions to obtain the necessary inspection data for product assembly and quality assessment.

[0003] However, the above-mentioned testing methods mostly rely on manual contact operations. During the measurement process, the measuring instrument comes into contact with the surface of the ceramic shell, which poses a risk of scratching the product surface. At the same time, the number of measurement points for manual testing is limited, making it difficult to cover the overall shape of the plane to be measured. The test results are easily affected by wear of the feeler gauge, differences in operator perception, and differences in the location of the sampling points, which limits the testing efficiency and consistency of results and makes it difficult to meet the needs of batch and online testing. Summary of the Invention

[0004] This application addresses the technical problems of existing arc-extinguishing chamber ceramic shell flatness and parallelism testing, such as the risk of contact damage, insufficient measurement point coverage, and limited testing efficiency and consistency, by providing a non-contact method and system for testing the flatness and parallelism of arc-extinguishing chamber ceramic shells.

[0005] To achieve the above objectives, this application adopts the following technical solution: The first aspect of this application provides a non-contact method for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber, comprising: The ceramic shell of the arc-extinguishing chamber to be tested is positioned in the measurement area of ​​the non-contact laser scanning system, and the first and second test planes are determined. Calibrate the laser displacement sensor and the two-dimensional moving platform, and establish the correspondence between the vertical distance collected by the laser displacement sensor and the motion coordinates of the two-dimensional moving platform; The two-dimensional moving platform is controlled to drive the laser displacement sensor to perform rectangular grid scanning on the first and second planes to be measured along the X-axis and Y-axis respectively. Based on the vertical distance and corresponding motion coordinates collected at each measuring point, the first three-dimensional coordinate set and the second three-dimensional coordinate set are obtained. Abnormal outliers in the first and second 3D coordinate sets are removed respectively to obtain the first and second effective 3D coordinate sets. Least square plane fitting is performed on the first effective three-dimensional coordinate set and the second effective three-dimensional coordinate set respectively to obtain the first fitting reference plane and the second fitting reference plane; Based on the difference between the maximum and minimum distances from the measuring points in each effective three-dimensional coordinate set to the corresponding fitted reference plane, the flatness error of the first and second measured planes is determined. Using the first fitting reference plane as the parallelism evaluation benchmark, the parallelism error between the first and second test planes is determined and the detection result is output based on the difference between the maximum and minimum signed distances from the measurement points in the second effective three-dimensional coordinate set to the first fitting reference plane.

[0006] Furthermore, the laser displacement sensor is a triangular reflection laser displacement sensor; the triangular reflection laser displacement sensor emits laser light towards the first or second plane to be measured, and calculates the vertical distance from the corresponding measuring point to the triangular reflection laser displacement sensor based on the position of the reflected light spot.

[0007] Furthermore, the rectangular grid scanning includes: controlling the two-dimensional moving platform to move at a constant speed along the X-axis and Y-axis according to a preset scanning range, a preset scanning step distance, and a preset scanning speed, so that the scanning measurement points of the laser displacement sensor uniformly cover the first and second test planes.

[0008] Furthermore, the rectangular grid scanning includes: performing grid scanning on the plane to be measured at a scanning step of 2mm, and acquiring the three-dimensional coordinates of the points to be measured.

[0009] Furthermore, the step of removing outliers from the first and second three-dimensional coordinate sets respectively includes: performing initial least-squares plane fitting on the first and second three-dimensional coordinate sets respectively, and calculating the signed residual r of each measurement point relative to the corresponding initial fitting plane. i ; Calculate the signed residual r in the same three-dimensional coordinate set i The mean μ and standard deviation σ, when |r i When -μ|>3σ, the corresponding measurement point is identified as an outlier and removed. The first set of three-dimensional coordinates after removing outliers is taken as the first effective set of three-dimensional coordinates, and the second set of three-dimensional coordinates after removing outliers is taken as the second effective set of three-dimensional coordinates.

[0010] Furthermore, the least squares plane fitting includes: representing the fitting reference plane as Ax + By + Cz + D = 0; for the coordinates (x,y,cz,d) of the n measurement points participating in the fitting... i y i , z iBy minimizing the sum of the squared distances from each measuring point to the fitting reference plane, the coefficients A, B, C, and D of the plane equation are solved to construct either the first or second fitting reference plane.

[0011] Furthermore, the distance d from each measuring point to the corresponding fitting reference plane... i Represented as:

[0012] Where A, B, C, and D represent the plane equation coefficients corresponding to the fitted reference plane, x i y i , z i Let d represent the three-dimensional coordinates of the i-th measurement point. i This represents the distance from the i-th measurement point to the corresponding fitted reference plane.

[0013] Furthermore, the step of using the first fitting reference plane as the parallelism evaluation benchmark, and determining the parallelism error between the first and second planes to be measured based on the difference between the maximum and minimum signed distances from the measuring points in the second effective three-dimensional coordinate set to the first fitting reference plane, includes: representing the first fitting reference plane as A1x+B1y+C1z+D1=0, and the signed distance p from the j-th measuring point in the second effective three-dimensional coordinate set to the first fitting reference plane. j Represented as:

[0014] Where A1, B1, C1, and D1 represent the plane equation coefficients of the first fitted reference plane, x j y j z j Represent the three-dimensional coordinates of the j-th measurement point in the second effective three-dimensional coordinate set; and represent the signed distances p. j The difference between the maximum and minimum values ​​in the equation is determined as the parallelism error.

[0015] The second aspect of this application provides a non-contact system for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber, including a laser displacement sensor, a two-dimensional moving platform, a motion controller, a data acquisition module, and a data processing terminal; The laser displacement sensor is used to collect the vertical distance between each measuring point on the first and second measured planes of the ceramic shell of the arc-extinguishing chamber under test. The two-dimensional mobile platform is used to drive the laser displacement sensor to perform rectangular grid scanning on the first and second test planes along the X-axis and Y-axis directions. The motion controller is connected to the two-dimensional mobile platform and is used to control the scanning range, scanning step distance and scanning speed of the two-dimensional mobile platform; The data acquisition module is connected to the laser displacement sensor and is used to receive the vertical distance of each measuring point, and combine it with the motion coordinates of the two-dimensional moving platform to obtain a first three-dimensional coordinate set and a second three-dimensional coordinate set. The data processing terminal is connected to the data acquisition module and is used to remove outliers from the first and second three-dimensional coordinate sets to obtain a first effective three-dimensional coordinate set and a second effective three-dimensional coordinate set; perform least squares plane fitting on the first and second effective three-dimensional coordinate sets to obtain a first fitting reference plane and a second fitting reference plane; and determine and output the flatness error and parallelism error according to the method described in claim 1.

[0016] Furthermore, the two-dimensional mobile platform is a two-dimensional gantry-type mobile scanning mechanism, and the laser displacement sensor is vertically mounted on the mobile end of the two-dimensional gantry-type mobile scanning mechanism; the data processing terminal has a built-in least squares plane fitting algorithm and a 3σ outlier removal algorithm, and is used to generate a detection report and display the height distribution cloud map of the first and second test planes.

[0017] Compared with the prior art, this application has the following beneficial effects: By positioning the ceramic shell of the arc-extinguishing chamber under test within the measurement area of ​​a non-contact laser scanning system, and utilizing a laser displacement sensor in conjunction with a two-dimensional moving platform to perform rectangular grid scanning on the first and second test planes, three-dimensional coordinate data covering the test planes can be obtained without contacting the ceramic shell surface. This reduces the risk of surface damage caused by contact measurement and improves the problem of limited manual sampling points and insufficient measurement point coverage. System calibration establishes the correspondence between vertical distance and motion coordinates, ensuring that the measurement data of the two test planes are in a unified measurement coordinate system, guaranteeing consistent data benchmarks for parallelism calculation. Outlier point removal and least-squares plane fitting reduce the impact of abnormal measurement points on the detection results, and the flatness error of the first and second test planes is calculated based on the fitted reference plane. Furthermore, using the first fitted reference plane as the parallelism evaluation benchmark, the parallelism error is determined based on the signed distance from the measurement points in the second effective three-dimensional coordinate set to the first fitted reference plane. This achieves non-contact, automated detection of the flatness and parallelism of the arc-extinguishing chamber ceramic shell, improving detection efficiency and consistency of detection results. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A flowchart of a non-contact method for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber, provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a non-contact system for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber, provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Existing methods for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber rely heavily on manual contact measurement methods such as feeler gauges, platforms, and dial indicators. These methods suffer from drawbacks such as easy scratching of the product surface, low measurement efficiency, limited number of measurement points, and difficulty in overall online detection. To address these issues, this application proposes a non-contact method for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber. In short, the method first locates the ceramic shell of the arc-extinguishing chamber to be tested and determines the first and second test planes. Then, it calibrates a laser displacement sensor and a two-dimensional moving platform. Further, it obtains the first and second three-dimensional coordinate sets through rectangular grid scanning. After outlier removal and least-squares plane fitting, it obtains the first and second fitting reference planes. Finally, it calculates the flatness error and parallelism error and outputs the detection results.

[0021] In this embodiment, a non-contact scanning method is used in conjunction with a laser displacement sensor and a two-dimensional moving platform, which effectively solves the problem that contact measurement is prone to damaging the surface of the ceramic shell of the arc-extinguishing chamber. The three-dimensional coordinates of multiple measuring points are obtained by scanning with a rectangular grid, which improves the integrity of the overall detection of the plane under test. Furthermore, through the elimination of outlier points, least squares plane fitting and error calculation, the automatic output of flatness and parallelism detection results is realized.

[0022] like Figure 1 As shown in the figure, this application provides a non-contact method for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber, specifically including the following steps: S1, Position the ceramic shell of the arc-extinguishing chamber to be tested in the measurement area of ​​the non-contact laser scanning system, and determine the first and second test planes.

[0023] Specifically, the ceramic shell of the arc-extinguishing chamber under test is an insulating ceramic shell used in vacuum arc-extinguishing chamber switches. The measurement area is the region where the laser displacement sensor can scan and measure the distance of the ceramic shell of the arc-extinguishing chamber under test. The first and second measured planes are two surfaces that need to be tested for flatness and whose parallelism needs to be evaluated. Through this step, the objects for subsequent scanning, coordinate acquisition, fitting, and error calculation are determined.

[0024] S2, calibrate the laser displacement sensor and the two-dimensional moving platform, and establish the correspondence between the vertical distance collected by the laser displacement sensor and the motion coordinates of the two-dimensional moving platform.

[0025] Specifically, system calibration is used to calibrate the installation relationship and coordinate correspondence between the laser displacement sensor and the two-dimensional moving platform. The two-dimensional moving platform provides the motion coordinates of the measuring point in the X and Y axes, and the laser displacement sensor collects the vertical distance from the measuring point to the laser displacement sensor. By establishing the correspondence between the vertical distance and the motion coordinates, the same measuring point can form three-dimensional coordinates including planar position and height information. The scanning data of the first and second measured planes use the same positioning reference and the same measurement coordinate system; when it is necessary to change the scanning posture of the ceramic shell of the arc-extinguishing chamber under test during the scanning process, the measurement data before and after the posture change are converted to the same measurement coordinate system through the pre-determined positioning reference.

[0026] S3, control the two-dimensional moving platform to drive the laser displacement sensor to perform rectangular grid scanning on the first and second planes to be measured along the X-axis and Y-axis respectively, and obtain the first three-dimensional coordinate set and the second three-dimensional coordinate set based on the vertical distance and corresponding motion coordinates collected by each measuring point.

[0027] Specifically, during the scanning process, the two-dimensional moving platform scans line by line along the X-axis and shifts along the Y-axis between adjacent scan lines according to a preset scanning step distance; or it scans column by column along the Y-axis and shifts along the X-axis between adjacent scan columns according to a preset scanning step distance, so that the laser displacement sensor sequentially reaches each measurement point position in the rectangular grid. For any measurement point, the motion coordinates of the two-dimensional moving platform are used as the planar coordinates of the measurement point, and the vertical distance collected by the laser displacement sensor is used as the height coordinate of the measurement point, thus forming the three-dimensional coordinates of the measurement point. The three-dimensional coordinates of multiple measurement points on the first plane to be measured constitute the first three-dimensional coordinate set, and the three-dimensional coordinates of multiple measurement points on the second plane to be measured constitute the second three-dimensional coordinate set.

[0028] S4, respectively remove outliers from the first and second three-dimensional coordinate sets to obtain the first and second effective three-dimensional coordinate sets.

[0029] Specifically, outliers can be measurement points that significantly deviate from the overall data distribution due to abnormal laser reflection, edge interference, instantaneous vibration, or acquisition noise. Initial least-squares plane fitting is performed on the first and second 3D coordinate sets respectively, and the signed residual *ri* of each measurement point relative to the corresponding initial fitting plane is calculated. The mean *μ* and standard deviation *σ* of the signed residuals *ri* in the same 3D coordinate set are calculated. When |ri-μ|>3σ, the corresponding measurement point is identified as an outlier and removed. The first 3D coordinate set after removing outliers is taken as the first effective 3D coordinate set, and the second 3D coordinate set after removing outliers is taken as the second effective 3D coordinate set. The first and second effective 3D coordinate sets are used as data inputs for subsequent plane fitting.

[0030] S5, perform least squares plane fitting on the first effective three-dimensional coordinate set and the second effective three-dimensional coordinate set respectively to obtain the first fitting reference plane and the second fitting reference plane.

[0031] Specifically, the measuring points in the first effective three-dimensional coordinate set are used to fit the overall spatial state of the first plane to be measured, obtaining the first fitting reference plane; the measuring points in the second effective three-dimensional coordinate set are used to fit the overall spatial state of the second plane to be measured, obtaining the second fitting reference plane. The first and second fitting reference planes serve as the references for subsequent flatness error calculations, with the first fitting reference plane also serving as the evaluation reference for parallelism error calculations.

[0032] S6. Based on the difference between the maximum and minimum distances from the measuring points in each effective three-dimensional coordinate set to the corresponding fitting reference plane, determine the flatness error of the first and second measured planes.

[0033] Specifically, the distance from each measuring point in the first effective three-dimensional coordinate set to the first fitting reference plane is calculated, and the difference between the maximum and minimum distances is taken as the flatness error of the first plane to be measured. Similarly, the distance from each measuring point in the second effective three-dimensional coordinate set to the second fitting reference plane is calculated, and the difference between the maximum and minimum distances is taken as the flatness error of the second plane to be measured. Thus, the flatness error is determined jointly by the effective measuring points, the corresponding fitting reference plane, and the distances between the measuring points, avoiding judgment based solely on a small number of manually selected points.

[0034] S7. Using the first fitting reference plane as the parallelism evaluation reference, the parallelism error between the first test plane and the second test plane is determined and the detection result is output based on the difference between the maximum and minimum signed distances from the measurement points in the second effective three-dimensional coordinate set to the first fitting reference plane.

[0035] Specifically, each measuring point in the second effective three-dimensional coordinate set is the object of parallelism error evaluation, and the first fitting reference plane is the unified evaluation reference. By calculating the signed distance from each measuring point in the second effective three-dimensional coordinate set to the first fitting reference plane, the deviation of the second test plane relative to the first fitting reference plane can be obtained. The difference between the maximum and minimum signed distances is used to represent the parallelism error between the first and second test planes. The detection results include the flatness error of the first and second test planes, as well as the parallelism error between them.

[0036] In a further preferred embodiment of this application, the laser displacement sensor is a triangular reflective laser displacement sensor; the triangular reflective laser displacement sensor emits laser light toward the first plane to be measured or the second plane to be measured, and calculates the vertical distance from the corresponding measuring point to the triangular reflective laser displacement sensor based on the position of the reflected light spot.

[0037] Specifically, the laser emitted by the triangular reflective laser displacement sensor illuminates the first or second plane to be measured, forming a reflected light spot. The sensor calculates the vertical distance from the measuring point to the sensor based on the position change of the reflected light spot in the receiving unit. This vertical distance proceeds to step S30, where it, together with the corresponding motion coordinates provided by the two-dimensional moving platform, forms the three-dimensional coordinates of the measuring point.

[0038] In this embodiment, by employing a triangular reflective laser displacement sensor, the vertical distance can be obtained without contacting the ceramic shell surface of the arc-extinguishing chamber, thereby providing height data for the subsequent establishment of a three-dimensional coordinate set.

[0039] In a further preferred embodiment of this application, the rectangular grid scanning includes: controlling a two-dimensional moving platform to move at a constant speed along the X-axis and Y-axis according to a preset scanning range, a preset scanning step distance, and a preset scanning speed, so that the scanning measurement points of the laser displacement sensor uniformly cover the first and second planes to be measured.

[0040] Specifically, the preset scanning range is determined based on the measured areas of the first and second measured planes, the preset scanning step distance is used to determine the spacing between adjacent measuring points, and the preset scanning speed is used to determine the moving speed of the laser displacement sensor relative to the measured plane. The motion controller controls the movement of the two-dimensional moving platform according to the preset scanning range, preset scanning step distance, and preset scanning speed, so that the measuring points form a rectangular grid distribution on the first and second measured planes.

[0041] In one specific embodiment, the rectangular grid scanning includes performing grid scanning on the plane to be measured at a scanning step of 2mm to acquire the three-dimensional coordinates of the points to be measured.

[0042] In this embodiment of the application, the scanning points are uniformly covered on the plane to be measured by scanning with a rectangular grid, which can reduce the impact of differences in manual point selection on the detection results and provide more complete measurement point data for least squares plane fitting.

[0043] In a further preferred embodiment of this application, the step of removing outliers from the first three-dimensional coordinate set and the second three-dimensional coordinate set respectively includes: processing the first three-dimensional coordinate set and the second three-dimensional coordinate set respectively using a 3σ outlier removal algorithm, taking the first three-dimensional coordinate set after removing outliers as the first effective three-dimensional coordinate set, and taking the second three-dimensional coordinate set after removing outliers as the second effective three-dimensional coordinate set.

[0044] Specifically, the 3σ outlier removal algorithm is used to identify measurement points that deviate from the overall data distribution. For the first 3D coordinate set, after removing outliers, the remaining measurement points are added to the first valid 3D coordinate set; for the second 3D coordinate set, after removing outliers, the remaining measurement points are added to the second valid 3D coordinate set. The first and second valid 3D coordinate sets are then used for least-squares plane fitting in step S50.

[0045] In this embodiment of the application, by removing outliers before fitting, the impact of abnormal acquisition values ​​on the fitting reference plane and error calculation results can be reduced, thereby improving the consistency of the detection results.

[0046] In a further preferred embodiment of this application, the least squares plane fitting includes: representing the fitting reference plane as Ax+By+Cz+D=0; for the coordinates of the n measurement points participating in the fitting (x i y i , z i By minimizing the sum of the squared distances from each measuring point to the fitting reference plane, the coefficients A, B, C, and D of the plane equation are solved to construct either the first or second fitting reference plane.

[0047] The fitting reference plane is represented as: Ax + By + Cz + D = 0.

[0048] Where A, B, C, and D represent the plane equation coefficients of the fitted reference plane, and x, y, and z represent the spatial coordinate variables.

[0049] For the coordinates (x, y) of the n measurement points involved in the fitting... i y i , z iThe objective of least-squares plane fitting is to minimize the sum of the squared distances from each measurement point to the fitting reference plane. By solving for the plane equation coefficients A, B, C, and D that satisfy this objective, a fitting reference plane that matches the corresponding effective three-dimensional coordinate set can be constructed. The first effective three-dimensional coordinate set corresponds to the first fitting reference plane, and the second effective three-dimensional coordinate set corresponds to the second fitting reference plane.

[0050] In a further preferred embodiment of this application, the distance d from each measuring point to the corresponding fitting reference plane is... i Represented as:

[0051] Where A, B, C, and D represent the plane equation coefficients corresponding to the fitted reference plane, x i y i , z i Let d represent the three-dimensional coordinates of the i-th measurement point. i This represents the distance from the i-th measurement point to the corresponding fitted reference plane.

[0052] Specifically, for the first effective three-dimensional coordinate set, the distance d between each measuring point is calculated using the plane equation coefficients of the first fitting reference plane. i And based on the distance d i The difference between the maximum and minimum values ​​yields the flatness error of the first plane to be measured. For the second effective three-dimensional coordinate set, the distance d between each measuring point is calculated using the plane equation coefficients of the second fitted reference plane. i And based on the distance d i The difference between the maximum and minimum values ​​yields the flatness error of the second plane to be measured.

[0053] In this embodiment, by using least squares plane fitting and measuring point distance calculation, the effective three-dimensional coordinate set can be transformed into a fitting reference plane and flatness error, avoiding the lack of necessary data connection relationships when describing the results only as "fitting" or "calculation".

[0054] In a further preferred embodiment of this application, the step of using the first fitting reference plane as the parallelism evaluation benchmark and determining the parallelism error between the first and second test planes based on the difference between the maximum and minimum signed distances from the measurement points in the second effective three-dimensional coordinate set to the first fitting reference plane includes: representing the first fitting reference plane as A1x+B1y+C1z+D1=0, and the signed distance p from the j-th measurement point in the second effective three-dimensional coordinate set to the first fitting reference plane... j Represented as:

[0055] Where A1, B1, C1, and D1 represent the plane equation coefficients of the first fitted reference plane, x j y j z j p represents the three-dimensional coordinates of the j-th measurement point in the second effective three-dimensional coordinate set. j This represents the signed distance from the j-th measurement point in the second effective three-dimensional coordinate set to the first fitting reference plane.

[0056] Specifically, the normal vector of the first fitting reference plane is (A1, B1, C1), and the signed distance p j This represents the deviation of the j-th measurement point in the second effective 3D coordinate set from the first fitting reference plane along the direction of the normal vector. The signed distance p of each measurement point in the second effective 3D coordinate set is calculated. j Then, the signed distance p of each is... j The difference between the maximum and minimum values ​​in the coordinate system is determined as the parallelism error. Therefore, a continuous data processing relationship is formed between the measurement points in the second effective three-dimensional coordinate set, the first fitting reference plane, the signed distance, and the parallelism error.

[0057] In this embodiment of the application, by using the first fitting reference plane as a unified evaluation reference and calculating the parallelism error using the signed distance from each measuring point in the second effective three-dimensional coordinate set to the reference plane, the parallelism between the first test plane and the second test plane can be quantitatively evaluated.

[0058] In one specific embodiment, the non-contact laser scanning system includes a laser displacement sensor, a two-dimensional moving platform, a motion controller, a data acquisition module, and a data processing terminal. The laser displacement sensor is a triangular reflective laser displacement sensor with a measurement accuracy of ±1μm and a sampling frequency of at least 1000Hz. The two-dimensional moving platform drives the laser displacement sensor to scan a rectangular grid along the X and Y axes. The motion controller controls the scanning range, scanning step distance, and scanning speed of the two-dimensional moving platform. The data acquisition module acquires the vertical distance output by the laser displacement sensor and combines it with the motion coordinates of the two-dimensional moving platform to form a three-dimensional coordinate set. The data processing terminal performs outlier removal, least-squares plane fitting, flatness error calculation, and parallelism error calculation on the three-dimensional coordinate set, and outputs the detection results.

[0059] In this specific embodiment, a 100mm × 100mm plane to be measured is scanned using a grid with a scanning step of 2mm, acquiring the three-dimensional coordinates of 2601 measuring points. The data processing terminal uses a 3σ outlier removal algorithm to eliminate outliers, then uses the least squares method to perform plane fitting on the valid measuring points, and determines the flatness error based on the difference between the maximum and minimum distances from the measuring points to the corresponding fitted reference plane. The data processing terminal can also generate a detection report and display the height distribution cloud maps of the first and second measured planes.

[0060] On the other hand, such as Figure 2 As shown in the embodiments of this application, a non-contact system for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber is also provided, including a laser displacement sensor, a two-dimensional moving platform, a motion controller, a data acquisition module, and a data processing terminal.

[0061] The laser displacement sensor is used to acquire the vertical distance between each measuring point on the first and second measuring planes of the ceramic shell of the arc-extinguishing chamber under test. Specifically, the laser displacement sensor can be a triangular reflection laser displacement sensor, which emits a laser beam towards the first or second measuring plane and calculates the vertical distance from the corresponding measuring point to the laser displacement sensor based on the position of the reflected light spot.

[0062] A two-dimensional moving platform is used to drive the laser displacement sensor to perform rectangular grid scanning of the first and second test planes along the X and Y axes. Specifically, the two-dimensional moving platform can be a two-dimensional gantry-type moving scanning mechanism, with the laser displacement sensor vertically mounted on the moving end of the two-dimensional gantry-type moving scanning mechanism. The two-dimensional gantry-type moving scanning mechanism moves along the X and Y axes, causing the laser displacement sensor to sequentially reach the measurement points in the rectangular grid.

[0063] A motion controller is connected to the two-dimensional mobile platform and is used to control the scanning range, scanning step distance, and scanning speed of the two-dimensional mobile platform. Specifically, the motion controller controls the movement of the two-dimensional mobile platform according to a preset scanning range, preset scanning step distance, and preset scanning speed, so that the scanning measurement points uniformly cover the first and second planes to be measured.

[0064] The data acquisition module is connected to the laser displacement sensor and is used to receive the vertical distance of each measuring point. Combined with the motion coordinates of the two-dimensional moving platform, it obtains a first set of three-dimensional coordinates and a second set of three-dimensional coordinates. Specifically, the data acquisition module matches the vertical distance at the same measuring point with the motion coordinates of the two-dimensional moving platform to form the three-dimensional coordinates of that measuring point. The three-dimensional coordinates of multiple measuring points respectively constitute the first set of three-dimensional coordinates and the second set of three-dimensional coordinates.

[0065] The data processing terminal is connected to the data acquisition module and is used to remove outliers from the first and second three-dimensional coordinate sets to obtain the first and second effective three-dimensional coordinate sets; perform least squares plane fitting on the first and second effective three-dimensional coordinate sets to obtain the first and second fitting reference planes; and determine and output the flatness error and parallelism error according to the above method.

[0066] Furthermore, the data processing terminal incorporates a least squares plane fitting algorithm and a 3σ outlier removal algorithm, which are used to generate detection reports and display height distribution cloud maps of the first and second test planes.

[0067] In this embodiment, the laser displacement sensor outputs the vertical distance, the two-dimensional moving platform provides the motion coordinates, the data acquisition module matches the vertical distance with the motion coordinates to form a three-dimensional coordinate set, the data processing terminal performs outlier removal, plane fitting and error calculation on the three-dimensional coordinate set, and the motion controller controls the scanning motion of the two-dimensional moving platform, thereby forming a complete coordination relationship between acquisition, motion, data processing and result output.

[0068] In summary, this application provides a method and system for non-contact inspection of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber. By using a laser displacement sensor in conjunction with a two-dimensional moving platform to perform rectangular grid scanning, it effectively solves the problems of easy damage to the product surface, limited number of measurement points, and low inspection efficiency associated with manual contact measurement. By utilizing three-dimensional coordinate sets, outlier removal, and least-squares plane fitting, the completeness and stability of the overall inspection of the plane under test are improved. Furthermore, by outputting flatness error and parallelism error, non-contact automatic inspection of the shape and position dimensions of the ceramic shell of the arc-extinguishing chamber is achieved.

[0069] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0070] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A non-contact method for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber, characterized in that, include: The ceramic shell of the arc-extinguishing chamber to be tested is positioned in the measurement area of ​​the non-contact laser scanning system, and the first and second test planes are determined. Calibrate the laser displacement sensor and the two-dimensional moving platform, and establish the correspondence between the vertical distance collected by the laser displacement sensor and the motion coordinates of the two-dimensional moving platform; The two-dimensional moving platform is controlled to drive the laser displacement sensor to perform rectangular grid scanning on the first and second planes to be measured along the X-axis and Y-axis respectively. Based on the vertical distance and corresponding motion coordinates collected at each measuring point, the first three-dimensional coordinate set and the second three-dimensional coordinate set are obtained. Abnormal outliers in the first and second 3D coordinate sets are removed respectively to obtain the first and second effective 3D coordinate sets. Least square plane fitting is performed on the first effective three-dimensional coordinate set and the second effective three-dimensional coordinate set respectively to obtain the first fitting reference plane and the second fitting reference plane; Based on the difference between the maximum and minimum distances from the measuring points in each effective three-dimensional coordinate set to the corresponding fitted reference plane, the flatness error of the first and second measured planes is determined. Using the first fitting reference plane as the parallelism evaluation benchmark, the parallelism error between the first and second test planes is determined and the detection result is output based on the difference between the maximum and minimum signed distances from the measurement points in the second effective three-dimensional coordinate set to the first fitting reference plane.

2. The method for non-contact testing of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber according to claim 1, characterized in that, The laser displacement sensor is a triangular reflective laser displacement sensor; the triangular reflective laser displacement sensor emits laser light towards the first or second plane to be measured, and calculates the vertical distance from the corresponding measuring point to the triangular reflective laser displacement sensor based on the position of the reflected light spot.

3. The method for non-contact testing of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber according to claim 1, characterized in that, The rectangular grid scanning includes: controlling a two-dimensional moving platform to move at a constant speed along the X-axis and Y-axis according to a preset scanning range, preset scanning step distance and preset scanning speed, so that the scanning measurement points of the laser displacement sensor uniformly cover the first and second planes to be measured.

4. The method for non-contact testing of the flatness and parallelism of the ceramic shell of the arc-extinguishing chamber according to claim 3, characterized in that, The rectangular grid scanning includes: performing grid scanning on the plane to be measured at a scanning step of 2mm, and acquiring the three-dimensional coordinates of the points to be measured.

5. The method for non-contact testing of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber according to claim 1, characterized in that, The step of removing outliers from the first and second three-dimensional coordinate sets includes: performing initial least-squares plane fitting on the first and second three-dimensional coordinate sets respectively, and calculating the signed residual r of each measurement point relative to the corresponding initial fitting plane. i ; Calculate the signed residual r in the same three-dimensional coordinate set i The mean μ and standard deviation σ, when |r i When -μ|>3σ, the corresponding measurement point is identified as an outlier and removed. The first set of three-dimensional coordinates after removing outliers is taken as the first effective set of three-dimensional coordinates, and the second set of three-dimensional coordinates after removing outliers is taken as the second effective set of three-dimensional coordinates.

6. The method for non-contact testing of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber according to claim 1, characterized in that, The least squares plane fitting includes: representing the fitting reference plane as Ax + By + Cz + D = 0; for the coordinates of the n measurement points participating in the fitting (x i y i , z i By minimizing the sum of the squared distances from each measuring point to the fitting reference plane, the coefficients A, B, C, and D of the plane equation are solved to construct either the first or second fitting reference plane.

7. The method for non-contact testing of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber according to claim 6, characterized in that, The distance d from each measuring point to the corresponding fitting reference plane i Represented as: Where A, B, C, and D represent the plane equation coefficients corresponding to the fitted reference plane, x i y i , z i Let d represent the three-dimensional coordinates of the i-th measurement point. i This represents the distance from the i-th measurement point to the corresponding fitted reference plane.

8. The method for non-contact testing of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber according to claim 1, characterized in that, The method of using the first fitting reference plane as the parallelism evaluation benchmark, and determining the parallelism error between the first and second planes to be measured based on the difference between the maximum and minimum signed distances from the measuring points in the second effective three-dimensional coordinate set to the first fitting reference plane, includes: representing the first fitting reference plane as A1x+B1y+C1z+D1=0, and the signed distance p from the j-th measuring point in the second effective three-dimensional coordinate set to the first fitting reference plane. j Represented as: Where A1, B1, C1, and D1 represent the plane equation coefficients of the first fitted reference plane, x j y j z j Represent the three-dimensional coordinates of the j-th measurement point in the second effective three-dimensional coordinate set; and represent the signed distances p. j The difference between the maximum and minimum values ​​in the equation is determined as the parallelism error.

9. A non-contact system for detecting the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber, characterized in that, It includes a laser displacement sensor, a two-dimensional motion platform, a motion controller, a data acquisition module, and a data processing terminal; The laser displacement sensor is used to collect the vertical distance between each measuring point on the first and second measured planes of the ceramic shell of the arc-extinguishing chamber under test. The two-dimensional mobile platform is used to drive the laser displacement sensor to perform rectangular grid scanning on the first and second test planes along the X-axis and Y-axis directions. The motion controller is connected to the two-dimensional mobile platform and is used to control the scanning range, scanning step distance and scanning speed of the two-dimensional mobile platform; The data acquisition module is connected to the laser displacement sensor and is used to receive the vertical distance of each measuring point, and combine it with the motion coordinates of the two-dimensional moving platform to obtain a first three-dimensional coordinate set and a second three-dimensional coordinate set. The data processing terminal is connected to the data acquisition module and is used to remove abnormal outliers from the first three-dimensional coordinate set and the second three-dimensional coordinate set to obtain the first effective three-dimensional coordinate set and the second effective three-dimensional coordinate set. The first effective three-dimensional coordinate set and the second effective three-dimensional coordinate set are subjected to least squares plane fitting to obtain the first fitting reference plane and the second fitting reference plane; and the flatness error and parallelism error are determined and output according to the method described in claim 1.

10. The system for non-contact detection of the flatness and parallelism of the ceramic shell of an arc-extinguishing chamber according to claim 9, characterized in that, The two-dimensional mobile platform is a two-dimensional gantry-type mobile scanning mechanism, and the laser displacement sensor is vertically installed on the mobile end of the two-dimensional gantry-type mobile scanning mechanism; the data processing terminal has a built-in least squares plane fitting algorithm and a 3σ outlier removal algorithm, and is used to generate a detection report and display the height distribution cloud map of the first and second test planes.

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