Measuring method of deep blind hole curve profile based on point spectrum confocal sensor

Abstract

The present invention discloses a method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor, and belongs to the field of optical sensor technology. The measurement method includes: establishing a coordinate system for the deep blind hole, and importing the design profile of the deep blind hole into the coordinate system; combining the coordinate system and the design profile of the deep blind hole to form a trajectory line and determine the coordinates and starting point spacing of the trajectory line; providing a machine tool, on which an output shaft of the machine tool is provided a point spectrum confocal sensor, and inputting the coordinate system and trajectory line into the machine tool, so that the point spectrum confocal sensor sequentially scans the curve profile of the deep blind hole according to the trajectory line between two adjacent trajectory points, and constructs a curve with the scanned point data, starting point spacing and trajectory line in a three-dimensional model and rotates it to obtain the curve profile of the deep blind hole. The embodiment of the present invention provides a method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor, which can obtain an accurate deep blind hole curve profile.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical sensors, and in particular relates to a method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor. Background Art

[0002] As the proportion of large integral workpieces used in modern aircraft, ships, large precision instruments and other products continues to increase, the detection of deep blind holes also occurs frequently.

[0003] Currently, the detection methods for the curved profile of deep blind holes after machining (the inner diameter of the deep blind holes varies in the axial direction) mainly use contact measurement tools or laser scanning methods. Among them, contact measurement tools (such as internal diameter micrometers and pneumatic measuring instruments) rely on mechanical probes to contact the inner wall, which is prone to errors due to probe wear or insufficient rigidity. In the actual measurement process, the detection efficiency is low and the detection data sampling density is insufficient, making it difficult to ensure detection accuracy. The optical system corresponding to the laser scanning method is large and cannot be adapted to deep blind holes. In addition, due to the uneven reflection of the inner wall of the deep blind hole and the interference of oil and dust, the signal will be severely attenuated, making it difficult to ensure detection accuracy. Therefore, a detection method for the curved profile of blind holes is urgently needed to improve detection accuracy. Summary of the Invention

[0004] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a method for measuring the curve profile of a deep blind hole based on a point spectral confocal sensor. The purpose of the method is to control the point spectral confocal sensor to scan and construct the curve along the trajectory line in the coordinate system. The point spectral confocal sensor has high scanning accuracy and can obtain an accurate deep blind hole curve profile.

[0005] To achieve the above object, the present invention provides a method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor, the method comprising:

[0006] Establishing a coordinate system for the deep blind hole, wherein the coordinate system establishes a two-dimensional coordinate system with the central axis of the deep blind hole as the Y-axis and a radial direction as the X-axis, and importing the design outline of the deep blind hole into the coordinate system;

[0007] In combination with the coordinate system and the design profile of the deep blind hole, on the reference plane formed by the X-axis and the Y-axis, trajectory points are set with the X-axis as the corresponding position and moving to the corresponding positions in sequence along the Y-axis, and any two adjacent trajectory points are connected by a connecting line to form a trajectory line and determine the coordinates and starting point spacing of the trajectory line;

[0008] A machine tool is provided, wherein a point spectral confocal sensor is provided on an output shaft of the machine tool, and the coordinate system and the trajectory line are input to the machine tool, so that the point spectral confocal sensor sequentially scans the deep blind hole curve profile between two adjacent trajectory points along the trajectory line, and constructs a curve in a three-dimensional model using the scanned point data, the starting point spacing, and the trajectory line, and rotates the curve to obtain the deep blind hole curve profile;

[0009] In the X-axis direction, the spacing between each point on the trajectory line and the designed contour of the deep blind hole does not exceed the working distance of the point spectral confocal sensor. The height difference between the positions on the designed contour of the deep blind hole corresponding to any two adjacent trajectory points in the X-axis direction does not exceed the measuring range of the point spectral confocal sensor. The starting point spacing is the radial distance between the corresponding position of the trajectory line on the X-axis and the deep blind hole. The position of any point on each connecting line in the X-axis direction does not exceed the position range of the corresponding two trajectory points in the X-axis direction.

[0010] Optionally, the connecting line is a straight line segment.

[0011] Optionally, the connecting line is a broken line segment, and the broken line segment includes a first straight line segment and a second straight line segment connected to each other, the first straight line segment is parallel to the X axis, and the second straight line segment is parallel to the Y axis.

[0012] Optionally, 30 mm ≤ working distance ≤ 40 mm.

[0013] Optionally, the height difference between the positions on the design contour of the deep blind hole corresponding to any two adjacent trajectory points in the X-axis direction satisfies the following formula:

[0014] 80%≤Δx i / L≤90%;

[0015] Where Δx i is the height difference between any two adjacent track points on the designed contour of the deep blind hole in the X-axis direction, in mm; L is the range of the point spectrum confocal sensor, in mm.

[0016] Optionally, a connecting piece is provided on the output shaft of the machine tool, and the point spectrum confocal sensor is located on the connecting piece.

[0017] Optionally, the connecting member is a support rod or a knife rod.

[0018] Optionally, the ratio of the depth to the diameter of the deep blind hole is ≥10.

[0019] Optionally, the maximum inner diameter of the deep blind hole is ≥100 mm, and the depth of the deep blind hole is ≥1 m.

[0020] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0021] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0022] Regarding the method for measuring the curve profile of a deep blind hole based on a point spectral confocal sensor provided in an embodiment of the present invention, when measuring the curve profile of the deep blind hole, first, a coordinate system for the deep blind hole is established. The coordinate system establishes a two-dimensional coordinate system with the central axis of the deep blind hole as the Y-axis and a radial direction as the X-axis, and the designed contour of the deep blind hole is imported into the coordinate system. Through this coordinate system, not only the coordinates of the trajectory point can be confirmed, but also the coordinates of the subsequent trajectory line can be determined. At the same time, coordinate input can also be performed, so that the spectral confocal sensor of the machine tool control point scans according to the coordinates of the trajectory line.

[0023] Then, in conjunction with the coordinate system and the designed contour of the deep blind hole, on the reference plane formed by the X-axis and the Y-axis, trajectory points are set, with the X-axis as the corresponding position and the corresponding positions moved sequentially along the Y-axis. Any two adjacent trajectory points are connected by a connecting line to form a trajectory line and determine the coordinates and starting point spacing of the trajectory line. Setting multiple trajectory points enables the subsequent point spectral confocal sensor to scan sequentially between two adjacent trajectory points. This not only avoids the problem of insufficient scanning accuracy and large errors caused by the height difference between the positions of the designed contour of the deep blind hole corresponding to two adjacent trajectory points exceeding the range of the point spectral confocal sensor during the subsequent spectral confocal sensor scanning a section of the trajectory, but also avoids the problem of the distance between the point spectral confocal sensor and the deep blind hole exceeding the working distance of the point spectral confocal sensor during the subsequent scanning process. Finally, a machine tool is provided, a point spectrum confocal sensor is set on the output shaft of the machine tool, and a coordinate system and a trajectory line are input into the machine tool, so that the point spectrum confocal sensor performs point scanning on the deep blind hole curve profile between two adjacent trajectory points according to the trajectory line in turn, and constructs a curve with the scanned point data, starting point spacing and trajectory line in the three-dimensional model and rotates it to obtain the deep blind hole curve profile, thereby finally obtaining an accurate deep blind hole curve profile.

[0024] That is to say, an embodiment of the present invention provides a method for measuring the curve profile of a deep blind hole based on a point spectral confocal sensor. By controlling the point spectral confocal sensor to scan and construct a curve along a trajectory line in a coordinate system, the point spectral confocal sensor has high scanning accuracy and can obtain an accurate curve profile of a deep blind hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor provided by an embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of the arrangement of trajectory points provided by an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the arrangement of a trajectory line provided by an embodiment of the present invention;

[0028] Figure 4 It is a processing schematic diagram provided by an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the arrangement of a trajectory line provided by an embodiment of the present invention.

[0030] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0031] 1. Deep blind hole; 2. Point spectrum confocal sensor; 3. Connector; 4. Trajectory line; 41. Connecting line; 5. Design outline. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0035] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0037] Example:

[0038] Figure 1 FIG. 1 is a flow chart of a method for measuring the profile of a deep blind hole curve based on a point spectrum confocal sensor provided by an embodiment of the present invention. Figure 1 As shown, the measurement methods include:

[0039] S1. Establish a coordinate system for the deep blind hole 1. The coordinate system establishes a two-dimensional coordinate system with the center axis of the deep blind hole 1 as the Y axis and a radial direction (located on the end surface) as the X axis, and imports the design outline 5 of the deep blind hole 1 into the coordinate system.

[0040] It should be noted that the coordinate system can be established with the assistance of measurement tools.

[0041] S2. Combine the coordinate system and the design outline 5 of the deep blind hole 1 (the central axis of the design outline 5 of the deep blind hole 1 coincides with the Y axis in the coordinate system), and set the trajectory points on the reference plane formed by the X axis and the Y axis, with the X axis as the corresponding position and moving to the corresponding position in sequence along the Y axis (see Figure 2 A1, A2, A3, etc.), and connect any two adjacent track points through a connecting line 41 to form a track line 4 and determine the coordinates and starting point spacing of the track line 4 (see Figure 3 ).

[0042] S3. Provide a machine tool, on which a point spectrum confocal sensor 2 is provided on the output shaft of the machine tool, and input a coordinate system and a trajectory line 4 into the machine tool, so that the point spectrum confocal sensor 2 sequentially scans the curve profile of the deep blind hole 1 between two adjacent trajectory points along the trajectory line 4 (see Figure 4 ), and construct a curve with the scanned point data, starting point spacing and trajectory line 4 in the three-dimensional model and rotate it to obtain the curve profile of the deep blind hole 1.

[0043] The distance between each point of the track line 4 and the design outline 5 of the deep blind hole 1 in the X-axis direction does not exceed the working distance of the point spectrum confocal sensor 2, and the height difference Δx on the design outline 5 of the deep blind hole 1 corresponding to any two adjacent track points in the X-axis direction is i It does not exceed the measuring range of the point spectrum confocal sensor 2. The starting point spacing (i.e., ΔL1) is the radial distance between the corresponding position of the trajectory line 4 on the X-axis and the deep blind hole 1 (which can be obtained by a measuring tool). The position of any point on each connecting line in the X-axis direction does not exceed the position range of the corresponding two trajectory points in the X-axis direction.

[0044] In a method for measuring the curve profile of a deep blind hole based on a point spectral confocal sensor provided in an embodiment of the present invention, when measuring the curve profile of the deep blind hole 1, first, a coordinate system for the deep blind hole 1 is established. The coordinate system establishes a two-dimensional coordinate system with the central axis of the deep blind hole 1 as the Y-axis and a radial direction as the X-axis. The designed contour 5 of the deep blind hole 1 is then imported into the coordinate system. Through this coordinate system, not only the coordinates of the trajectory points can be confirmed, but also the coordinates of the subsequent trajectory line 4 can be determined. At the same time, coordinate input can also be performed, so that the machine tool control point spectral confocal sensor 2 scans according to the coordinates of the trajectory line 4.

[0045] Then, in conjunction with the coordinate system and the designed outline 5 of the deep blind hole 1, track points are set on the reference plane formed by the X-axis and the Y-axis, with the X-axis as the corresponding position and the Y-axis moving to the corresponding position in sequence. Any two adjacent track points are connected by a connecting line to form a track line 4, and the coordinates and starting point spacing of the track line 4 are determined. The setting of multiple track points enables the subsequent point spectral confocal sensor 2 to perform sequential scanning between two adjacent track points. This not only avoids the problem of insufficient scanning accuracy and large errors caused by the height difference between the positions of two adjacent track points on the designed outline 5 of the deep blind hole 1 corresponding to the subsequent spectral confocal sensor during a track scan exceeding the range of the point spectral confocal sensor 2, but also avoids the problem of the distance between the point spectral confocal sensor 2 and the deep blind hole 1 exceeding the working distance of the point spectral confocal sensor 2, resulting in an inability to perform scanning. Finally, a machine tool is provided, a point spectrum confocal sensor 2 is provided on the output shaft of the machine tool, and a coordinate system and a trajectory line 4 are input into the machine tool, so that the point spectrum confocal sensor 2 performs point scanning on the curve profile of the deep blind hole 1 according to the trajectory line 4 between two adjacent trajectory points in sequence (i.e., scanning from the end surface of the deep blind hole to its bottom), and constructs a curve with the scanned point data, the starting point spacing and the trajectory line 4 in the three-dimensional model and rotates it to obtain the curve profile of the deep blind hole 1, thereby finally obtaining an accurate curve profile of the deep blind hole 1.

[0046] That is to say, an embodiment of the present invention provides a method for measuring the curve profile of a deep blind hole based on a point spectral confocal sensor. By controlling the point spectral confocal sensor 2 to scan and construct a curve according to the trajectory line 4 in the coordinate system, the point spectral confocal sensor 2 has high scanning accuracy and can obtain an accurate curve profile of the deep blind hole 1.

[0047] It is easy to understand that the point spectrum confocal sensor 2 is a device that uses optical principles for measurement. It forms a focal point on the surface of the object to be measured by emitting light of different wavelengths. When the distance between the focal point and the surface of the object to be measured changes, the wavelength of the reflected light will also change accordingly. The point spectrum confocal sensor 2 provided by the present invention can scan each point of the deep blind hole 1 and its corresponding elevation difference during the movement along the trajectory line 4, thereby forming the contour line of each segment of the trajectory line in the X-axis direction (at this time, the spacing of the contour line relative to the Y-axis and the starting point spacing are unknown). On this basis, and combined with the coordinates of the trajectory line 4 and the starting point spacing, a complete and known curve is finally formed through integration, and the curve profile of the deep blind hole 1 is finally obtained.

[0048] In addition, since the size of the deep blind hole 1 finally formed in the workpiece during the fine machining process is close to the design contour 5, that is, the actual inner contour of the deep blind hole 1 is not much different from the size of the design contour 5, in order to quickly determine the position of each track point and reduce the number of track points, the present invention uses the design contour 5 as a reference for selecting each track point.

[0049] It is easy to understand that the position of any point on each connecting line in the X-axis direction does not exceed the position range of the corresponding two trajectory points in the X-axis direction, which can effectively constrain each point in the connecting line and avoid the problem that when the position of the connecting line in the X-axis direction exceeds the position range of the two trajectory points in the X-axis direction, there may be two points in the connecting line that exceed the range of the point spectrum confocal sensor 2, resulting in insufficient subsequent scanning accuracy.

[0050] Exemplarily, the ratio of the depth to the diameter of the deep blind hole 1 is ≥ 10. The maximum inner diameter of the deep blind hole 1 is ≥ 100 mm, and the depth of the deep blind hole 1 is ≥ 1 m.

[0051] In one implementation of the present invention, the connecting line is a straight line segment (see Figure 5 ). That is, the connecting line is a straight line connecting two corresponding trajectory points, so that the scanning path of the subsequent point spectral confocal sensor 2 is the shortest, thereby improving the scanning efficiency.

[0052] In another embodiment of the present invention, the connecting line 41 is a broken line segment (see Figure 2 ), the broken line segment includes a first straight line segment and a second straight line segment connected to each other, the first straight line segment is parallel to the X axis, and the second straight line segment is parallel to the Y axis.

[0053] That is to say, setting the connecting line 41 as a broken line segment can make the scanning path move along two coordinate axis directions (i.e., X-axis direction and Y-axis direction) successively, which can improve the accuracy of displacement scanning of the machine tool belt to the point spectral confocal sensor 2.

[0054] It is easy to understand that the output shaft of the machine tool has high precision control and a small error range when performing unidirectional displacement.

[0055] In this embodiment, 30 mm ≤ working distance ΔL i ≤40mm. That is, in the X-axis direction, the distance between each point on the trajectory line 4 and the design contour 5 is less than the working distance, ensuring that scanning can be performed.

[0056] Preferably, the working distances corresponding to the various trajectory points are equal (ie, ΔL1 = ΔL2 = ΔL3).

[0057] In addition, the height difference between the positions on the design contour 5 of the deep blind hole 1 corresponding to any two adjacent trajectory points in the X-axis direction satisfies the following formula:

[0058] 80%≤Δx i / L≤90%;

[0059] Where Δx iis the height difference between any two adjacent track points on the design contour 5 of the deep blind hole 1 (i.e., Δx1, Δx2, etc.; for example, Δx1 is the height difference between the positions of A1 and A2 on the design contour 5 corresponding to the two track points on the X-axis direction, respectively. 10 、A 20 , A 10 and A 20 The height difference in the X-axis direction is Δx1), mm; L is the measuring range of the point spectrum confocal sensor 2, mm.

[0060] In the above embodiment, Δx is controlled i The ratio of / L is between 80% and 90%, which can not only avoid the height difference between the positions on the design outline 5 of the deep blind hole 1 corresponding to any two adjacent track points in the X-axis direction being too large to exceed the range of the point spectrum confocal sensor 2, but also make it as close as possible to the range of the point spectrum confocal sensor 2, while ensuring the scanning accuracy and avoiding Δx i Too small will result in too many track points needing to be set.

[0061] See again Figure 4 A connector 3 is provided on the output shaft of the machine tool, and the point spectrum confocal sensor 2 is located on the connector 3. The connector 3 serves to connect the output shaft of the machine tool and the point spectrum confocal sensor 2 and avoid interference during scanning.

[0062] Furthermore, the connecting member 3 may be a support rod or a knife rod.

[0063] It is easy to understand that the measurement method provided by the present invention is also applicable to deep blind holes 1 with segments of the same diameter, that is, in this case, the point data corresponding to the scanning of the point spectrum confocal sensor 2 are the same in the X-axis direction.

[0064] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor, characterized in that: The measuring method comprises: Establishing a coordinate system for the deep blind hole, wherein the coordinate system establishes a two-dimensional coordinate system with the central axis of the deep blind hole as the Y-axis and a radial direction as the X-axis, and importing the design outline of the deep blind hole into the coordinate system; In combination with the coordinate system and the design profile of the deep blind hole, on the reference plane formed by the X-axis and the Y-axis, trajectory points are set at corresponding positions on the X-axis and at corresponding positions moved sequentially along the Y-axis, and any two adjacent trajectory points are connected by a connecting line to form a trajectory line and determine the coordinates and starting point spacing of the trajectory line; A machine tool is provided, wherein a point spectral confocal sensor is provided on an output shaft of the machine tool, and the coordinate system and the trajectory line are input to the machine tool, so that the point spectral confocal sensor sequentially scans the deep blind hole curve profile between two adjacent trajectory points along the trajectory line, and constructs a curve in a three-dimensional model using the scanned point data, the starting point spacing, and the trajectory line, and rotates the curve to obtain the deep blind hole curve profile; In the X-axis direction, the spacing between each point on the trajectory line and the designed contour of the deep blind hole does not exceed the working distance of the point spectral confocal sensor. The height difference between the positions on the designed contour of the deep blind hole corresponding to any two adjacent trajectory points in the X-axis direction does not exceed the measuring range of the point spectral confocal sensor. The starting point spacing is the radial distance between the corresponding position of the trajectory line on the X-axis and the deep blind hole. The position of any point on each connecting line in the X-axis direction does not exceed the position range of the corresponding two trajectory points in the X-axis direction.

2. The method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to claim 1, characterized in that: The connecting line is a straight line segment.

3. The method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to claim 1, characterized in that: The connecting line is a broken line segment, and the broken line segment includes a first straight line segment and a second straight line segment connected to each other, the first straight line segment is parallel to the X axis, and the second straight line segment is parallel to the Y axis.

4. The method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to claim 1, characterized in that: 30mm≤working distance≤40mm.

5. The method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to claim 1, characterized in that: The height difference between the positions on the design contour of the deep blind hole corresponding to any two adjacent trajectory points in the X-axis direction satisfies the following formula: 80%≤Δx i / L≤90%; Where Δx i is the height difference between any two adjacent track points on the designed contour of the deep blind hole in the X-axis direction, in mm; L is the range of the point spectrum confocal sensor, in mm.

6. The method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to claim 1, characterized in that: A connecting piece is provided on the output shaft of the machine tool, and the point spectrum confocal sensor is located on the connecting piece.

7. The method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to claim 6, characterized in that: The connecting piece is a support rod or a knife rod.

8. The method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to any one of claims 1 to 7, characterized in that: The ratio of the depth to the diameter of the deep blind hole is ≥10.

9. A method for measuring the curve profile of a deep blind hole based on a point spectrum confocal sensor according to any one of claims 1 to 7, characterized in that: The maximum inner diameter of the deep blind hole is ≥100 mm, and the depth of the deep blind hole is ≥1 m.

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