Automatic measuring device

Abstract

The system allows for automatic adjustment of any positional deviations in the part being measured. [Solution] A laser is irradiated towards multiple laser irradiation points D1 surrounding the measurement target part T of the workpiece W, and it is determined whether there are any undetected reflection points D1b among the multiple laser irradiation points D1, other than the point D1a where reflected laser light is detected. If an undetected reflection point D1b exists, a scanning center point CTR is set at a position shifted in the direction of the undetected reflection point D1b relative to the reference point C of the measurement target part T, and the laser is scanned along multiple scanning lines L1 passing through the scanning center point CTR to detect multiple edge points E1 of the measurement target part T, the position of the reference point C is updated based on the positions of the multiple edge points E1, and the measurement target part T' is measured using the updated reference point C', which is the updated reference point.

Description

[Technical Field]

[0001] The present invention relates to an automatic measuring device using a laser measuring machine. [Background Art]

[0002] There is a technology for automatically measuring the shape and dimensions of holes or protrusions on a workpiece using a laser measuring machine. According to the laser measuring machine, it is possible to accurately measure the shape or dimensions of the workpiece by acquiring point cloud data. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-257918 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] The actual position of a portion or part to be measured (hereinafter referred to as a "measurement target part") such as a hole in a workpiece may be deviated from a normal position or a designed position. If the deviation is large and the position of the measurement target part deviates from the initially scheduled measurement range, it becomes difficult to correctly measure the position of the measurement target part. In this case, when performing measurement, an operator needs to adjust the position of the laser irradiation point with respect to the workpiece.

[0005] This adjustment is generally performed manually for each measurement target part by the operator, for example, the operator grasps the deviation state based on their own judgment from the display of the point cloud obtained as the output of the laser measuring machine and the actual condition of the workpiece, and changes the measurement range in the direction in which the deviation has occurred.

[0006] However, accurately understanding the extent of the misalignment from the point cloud display requires sufficient knowledge of the laser measuring machine's characteristics and the workpiece design. Therefore, adjustments tend to depend on the operator's skill level, and even for skilled operators, it is not always easy or quick to perform. To ensure measurement is possible even when misalignment occurs, one could consider anticipating the range in which misalignment will occur and simply expanding the measurement range. However, this would require time for each measurement target, making it too time-consuming for numerous measurements.

[0007] In view of these circumstances, the present invention aims to provide an automatic measuring device that automatically adjusts for any misalignment of the part to be measured, thereby enabling measurement of the part to be measured. [Means for solving the problem]

[0008] To solve the aforementioned problems, an automatic control device according to one embodiment of the present invention irradiates a laser toward a plurality of laser irradiation points surrounding the part of the workpiece to be measured, determines whether there are any points among the plurality of laser irradiation points other than the points where reflected light of the laser is detected that are not reflected, and if there are any points that are not reflected, sets a scanning center point at a position shifted in the direction of the points that are not reflected relative to the reference point of the part of the workpiece to be measured, scans the laser along a plurality of scanning lines passing through the scanning center point to detect a plurality of edge points of the part of the workpiece to be measured, changes the position of the reference point based on the positions of the plurality of edge points, and measures the part of the workpiece to be measured using the changed reference point, which is the changed reference point. [Effects of the Invention]

[0009] According to one embodiment of the present invention, when a deviation occurs in the position of the part to be measured on a workpiece from its normal or design position, the reference point of the part to be measured, that is, the reference point for measurement by the laser measuring machine, can be adjusted using the laser measuring machine without the need for special or additional equipment, thereby mitigating or eliminating problems caused by the deviation of the part to be measured and enabling measurement to be performed. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the configuration of an automated measuring device relating to one embodiment of the present invention. [Figure 2] This flowchart shows the flow of the measurement mode setting process by the automatic measuring device. [Figure 3] This flowchart shows the flow of the measurement mode setting process by the automatic measuring device (part A in the flowchart shown in Figure 2). [Figure 4] This flowchart shows the flow of the measurement process using an automated measuring device. [Figure 5] This flowchart shows the flow of coordinate system adjustment processing by an automated measuring device. [Figure 6] This flowchart shows the flow of the measurement process when measuring stud bolts. [Figure 7] This flowchart shows the flow of the coordinate system adjustment process when measuring stud bolts. [Figure 8] This is an explanatory diagram showing the procedure for adjusting the coordinate system when measuring circular holes (determining whether or not there are points where reflection was not detected). [Figure 9] This is an explanatory diagram showing the procedure for adjusting the coordinate system when measuring a circular hole (setting the scanning center point and scanning with a laser). [Figure 10] This is an explanatory diagram showing the procedure for adjusting the coordinate system when measuring a circular hole (detection of the edge point and change of the measurement reference point). [Figure 11] This is an explanatory diagram showing the procedure for measuring round holes. [Figure 12] This is an explanatory diagram showing the procedure for adjusting the coordinate system when measuring a circular hole (setting the scanning center point and scanning with a laser). [Figure 13] This is an explanatory diagram showing the procedure for adjusting the coordinate system when measuring a circular hole (detection of the edge point and change of the measurement reference point). [Figure 14] This is an explanatory diagram showing the procedure for adjusting the coordinate system when measuring elongated holes (determining whether or not there are points where reflection was not detected). [Figure 15]It is an explanatory diagram showing the procedure for coordinate system adjustment (setting of a scanning center point and scanning by laser) when measuring an elongated hole. [Figure 16] It is an explanatory diagram showing the procedure for coordinate system adjustment (detection of edge points and change of measurement reference points) when measuring an elongated hole. [Figure 17] It is an explanatory diagram showing the procedure for coordinate system adjustment (inclination correction) when measuring an elongated hole. [Figure 18] It is an explanatory diagram showing the procedure of main measurement when measuring an elongated hole. [Figure 19] It is an explanatory diagram showing the procedure for coordinate system adjustment (setting of a scanning center point and scanning by laser) when measuring an elongated hole. [Figure 20] It is an explanatory diagram showing the procedure for coordinate system adjustment (detection of edge points and change of measurement reference points) when measuring an elongated hole. [Figure 21] It is an explanatory diagram showing the procedure for coordinate system adjustment (determination of presence or absence of undetected reflection points) when measuring a square hole. [Figure 22] It is an explanatory diagram showing the procedure for coordinate system adjustment (setting of a scanning center point and scanning by laser) when measuring a square hole. [Figure 23] It is an explanatory diagram showing the procedure for coordinate system adjustment (detection of edge points and change of measurement reference points) when measuring a square hole. [Figure 24] It is an explanatory diagram showing the procedure for coordinate system adjustment (inclination correction) when measuring a square hole. [Figure 25] It is an explanatory diagram showing the procedure of main measurement when measuring a square hole. [Figure 26] It is an explanatory diagram showing the procedure for coordinate system adjustment (setting of a scanning center point and scanning by laser) when measuring a square hole. [Figure 27] It is an explanatory diagram showing the procedure for coordinate system adjustment (detection of edge points and change of measurement reference points) when measuring a square hole. [Figure 28] It is an explanatory diagram showing the procedure for coordinate system adjustment (detection of a stud bolt) when measuring a stud bolt. [Figure 29]This is an explanatory diagram showing the procedure for adjusting the coordinate system (extracting the cylinder) when measuring stud bolts. [Figure 30] This is an explanatory diagram showing the procedure for adjusting the coordinate system (changing the bolt center) when measuring stud bolts. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings.

[0012] (Configuration of the automatic measuring device) The automatic measuring device 1 according to this embodiment (hereinafter referred to as "automatic measuring device") comprises, as its main components, a laser measuring machine 101, a controller 102, and a display 103.

[0013] The automatic measuring device 1 uses a laser measuring machine 101 to perform measurements on a predetermined part (hereinafter referred to as the "measurement target part") T of the workpiece W. In this embodiment, the automatic measuring device 1 detects any deviation of the measurement target part T from its normal position or design position (hereinafter, including the design position, the position where the measurement target part T should originally be located is referred to as the "normal position"). The device then adjusts the measurement of the measurement target part T in accordance with this deviation to measure the actual position and shape of the measurement target part T. Based on the measured values, it is possible to determine whether the measurement target part T on the workpiece W is formed as designed. Specifically, the measurement target part T may be a hole or a protrusion provided on the workpiece W.

[0014] In this embodiment, examples of holes in the workpiece W include round holes, elongated holes, and square holes, and an example of a stud bolt is shown as a protruding part. When the hole in the workpiece W is used as the measurement target, the center position of the hole is calculated, and when the stud bolt is used as the measurement target, the center position of the stud bolt (specifically, the center position on the surface of the workpiece W) is calculated. Based on the measured center position, it is determined whether the hole is formed or positioned in the correct location on the workpiece W, and whether the stud bolt is installed in the correct location on the workpiece W.

[0015] Design values ​​such as the center position and orientation of the hole that will be measured (part T) are stored in advance in the automatic measuring device 1, and the actual position and orientation of the hole are measured based on these design values. A three-dimensional coordinate system (x, y, z) is set, and the design values ​​of the position of the part T to be measured, such as the center position of the hole, are described as the origin O of this coordinate system. The origin O can be set to an appropriate position relative to the workpiece W as the origin of the coordinate system.

[0016] Work W refers to, for example, the subcomponents (hereinafter referred to as "subcomps") that make up the body of a vehicle. In vehicle body manufacturing, first, panels for each part are made using sheet metal (mainly pressed steel sheets), which is the raw material. Next, multiple panels are joined together by methods such as welding or bonding to construct subassemblies (i.e., subcomps). Then, by combining multiple subcomps, the entire vehicle body (the unpainted vehicle body, called the "white body") is constructed.

[0017] Work W is not limited to subcompressors; it can also be a panel or a white body. Furthermore, it can even be a painted body.

[0018] The laser measuring device 101 comprises a laser emitter 101a that emits a laser and a laser receiver 101b that detects the reflected light of the laser. Based on the time difference from the emission of the laser to the detection of the reflected light, and the phase difference between the incident light and the reflected light of the laser, it is possible to measure the distance from the laser measuring device 101 to the object (specifically, the point of incidence of the laser on the object) and to measure the relative position of the object with respect to the laser measuring device 101.

[0019] The laser measuring device 101 is, for example, a 3D laser scanner.

[0020] The controller 102 controls the operation of the laser measuring machine 101, including the emission of the laser and the detection of reflected light, and receives point cloud data acquired by the laser measuring machine 101. The controller 102 further performs calculations related to the measurement of the workpiece W based on the received point cloud data.

[0021] The controller 102 includes a CPU (Central Processing Unit) 102a, and calculations are performed by executing computer programs using the CPU 102a. The controller 102 further has a storage unit 102b in which a computer program for measurement (hereinafter referred to as the "measurement program") is pre-stored, and when performing calculations, the measurement program is read from the storage unit 102b and executed by the CPU 102a.

[0022] The point cloud data is information acquired by the laser measuring instrument 101 and includes information about the position or coordinates of each point that makes up the point cloud, in other words, the position or coordinates of the laser irradiation point on the object.

[0023] The display 103 presents the operator with visual information indicating the measurement results. The measurement results can also be presented not only visually, but also aurally via a speaker or other means.

[0024] (Overall flow of automated measurement) The measurement process using the automatic measuring device 1 will be explained below with reference to the flowcharts shown in Figures 2 to 5.

[0025] In this embodiment, the measurement by the automatic measuring device 1 is broadly divided into a measurement mode selection process and the main measurement process, the main measurement process including a coordinate system adjustment process. Figures 2 and 3 show the contents of the measurement mode selection process, and Figures 4 to 7 show the contents of the main measurement process. Figures 4 and 5 show the contents of the process when measuring a round hole, an elongated hole, or a square hole as the measurement target part T, and Figures 6 and 7 show the contents of the process when measuring a stud bolt as the measurement target part T. A round hole, an elongated hole, and a square hole are each forms of a "hole," and a stud bolt is one form of a "protruding part."

[0026] In the flowchart shown in Figure 2, step S111 determines the type of part T to be measured. Specifically, the automatic measuring device 1 reads information about the type of part T to be measured, which is stored in advance, and by referring to this information, it determines whether the part T to be measured is a hole or a protrusion, and in this embodiment, whether the part T to be measured is a round hole, an elongated hole, a square hole, or a stud bolt.

[0027] In S112, it is determined whether the part T to be measured is a round hole or not. If the part T to be measured is a round hole, proceed to S115; otherwise, proceed to S113.

[0028] In S113, it is determined whether the part to be measured T is an elongated hole or not. If the part to be measured T is an elongated hole, proceed to S116; otherwise, proceed to S114.

[0029] In S114, it is determined whether the part to be measured T is a rectangular hole or not. If the part to be measured T is a rectangular hole, proceed to S117; otherwise, proceed to S211 in the flowchart shown in Figure 3.

[0030] In S115, select the first measurement mode (automatic mode A) as the measurement mode. The first measurement mode is the measurement mode used when measuring round holes.

[0031] In S116, the second measurement mode (automatic mode B) is selected as the measurement mode. The second measurement mode is the measurement mode used when measuring elongated holes.

[0032] In S117, select the third measurement mode (automatic mode C) as the measurement mode. The third measurement mode is the measurement mode used when measuring square holes.

[0033] In the flowchart shown in Figure 3, step S211 reads the result of the discrimination performed in step S111, that is, the type of measurement target part T that was determined in step S111.

[0034] In S212, it is determined whether the part T to be measured is a stud bolt or not. If it is a stud bolt, proceed to S213; otherwise, proceed to S214.

[0035] In S213, select the fourth measurement mode (automatic mode D) as the measurement mode. The fourth measurement mode is the measurement mode used when measuring stud bolts.

[0036] In S214, since it does not fall under any of the first measurement modes (automatic mode A) through the fourth measurement mode (automatic mode D), the fifth measurement mode (manual mode) is selected as the measurement mode. The fifth measurement mode is used when measuring holes other than round holes, elongated holes, and square holes, or protrusions other than stud bolts. In other words, for special shapes that do not have a large number of parts to be measured, the fifth measurement mode (manual mode) is selected.

[0037] If the part to be measured T is a hole, specifically if the part to be measured T is a round hole, an elongated hole, or a square hole, the measurement process shall be carried out according to the flowcharts shown in Figures 4 and 5. If the part to be measured T is a stud bolt, the measurement process shall be carried out according to the flowcharts shown in Figures 6 and 7.

[0038] In this embodiment, the center position of the hole used for measurement is adjusted according to the displacement or actual position of the part T to be measured in the workpiece W, and a new coordinate system (hereinafter referred to as the "local coordinate system") is set. As mentioned above, the center position of the hole is, in design terms, the origin O of the three-dimensional coordinate system (x, y, z). When measuring a round hole, elongated hole, square hole, or stud bolt, the adjustment of the local coordinate system is performed automatically by the controller 102. On the other hand, when measuring holes other than round holes, elongated holes, and square holes, or protrusions other than stud bolts, the adjustment is performed manually by the operator when measuring the position or shape of those holes or protrusions.

[0039] Figure 4 shows the details of the measurement process when measuring a hole as the part to be measured T. In the flowchart shown in Figure 4, in S311, the laser measuring device 101 irradiates a laser towards each of the multiple laser irradiation points (hereinafter referred to as "first laser irradiation points") D1 set on the surface of the workpiece W so as to surround the part to be measured T (see Figure 8). The laser measuring device 101 then receives the reflected light of the irradiated laser. Among the first laser irradiation points D1, the points where reflected light is detected are identified as "reflection detection points" D1a, while the first laser irradiation points D1 other than the reflection detection points D1a, that is, the first laser irradiation points where reflected light is not detected, are identified as "reflection undetected points" D1b. The position of the first laser irradiation point D1 can be changed or switched depending on the type of measurement target T, such as a round hole or an elongated hole. In this embodiment, multiple first laser irradiation points D1 are arranged at equal intervals in the circumferential direction so as to surround the measurement target T, which is formed according to the design. The multiple first laser irradiation points D1 are set at positions with a certain margin so that they do not overlap with the hole even if the measurement target T is slightly deviated from its normal position, and are positioned at a distance from the edge of the measurement target T. The distance from the edge to each first laser irradiation point D1 is set to be equal to each other and smaller than the radius of the hole. In other words, a radial line segment is virtually defined connecting the center point of the hole in the design (i.e., the origin O) and each first laser irradiation point D1. The position of each first laser irradiation point D1 is set such that the intersection point of these line segments with the edge of the hole (the part to be measured T) is closer to each first laser irradiation point D1 than to the center point of the hole.

[0040] In S312, it is determined whether or not there is an undetected reflection point D1b at the first laser irradiation point D1. If there is an undetected reflection point D1b, the process proceeds to S313. If there is no undetected reflection point D1b, in other words, if reflected laser light is detected from all first laser irradiation points D1, the process proceeds to S314. As mentioned earlier, there is some margin in the position of the first laser irradiation point D1, so an undetected reflection point D1b at the first laser irradiation point D1 occurs when the position of the measurement target T deviates relatively significantly from the design value, i.e., the normal position.

[0041] In S313, to enable measurement in response to the displacement of the measurement target T, the center position of the measurement target T is moved to adjust the local coordinate system. When a hole, including a round hole, is used as the measurement target T, the adjustment of the local coordinate system is performed according to the procedure shown in the flowchart of Figure 5.

[0042] In S314, the laser is irradiated toward the region surrounded by multiple first laser irradiation points D1. For example, the laser is irradiated toward the center point of the measurement target T surrounded by the first laser irradiation points D1, which in this embodiment is the origin O of the coordinate system (x,y,z). This is an operation to confirm whether the measurement target T exists in the region surrounded by the first laser irradiation points D1.

[0043] In S315, it is determined whether or not the reflected light from the laser irradiated in S314 (which may be referred to as "central reflected light" below to distinguish it from the reflected light from the laser irradiation points surrounding the measurement target T) has been detected. If central reflected light is detected, the process proceeds to S316. Detection of central reflected light suggests that the measurement target T is significantly deviated from its normal position, to the point where it is outside the area surrounded by the first laser irradiation point D1. Conversely, if central reflected light is not detected, the process proceeds to S320. In this case, the measurement target T is located within the area surrounded by the first laser irradiation point D1, and measurement can be performed without adjusting the local coordinate system.

[0044] In S316, in order to search a wider area for the measurement target T which is significantly deviated from its normal position, the laser measuring device 101 irradiates a laser towards each of the multiple laser irradiation points (hereinafter referred to as "second laser irradiation points") D2, which are set at a wider distance from the measurement target T or its center point than the first laser irradiation point D1 (see Figure 12). The laser measuring device 101 then receives the reflected light of the irradiated laser. Among the second laser irradiation points D2, the point where reflected light is detected is identified as the reflection detection point D2a, while the second laser irradiation points D2 other than the reflection detection points D2a, that is, the second laser irradiation points where reflected light is not detected, are identified as the reflection undetected points D2b. In this embodiment, the number of second laser irradiation points D2 is set to be greater than the number of first laser irradiation points D1. Specifically, the second laser irradiation point D2 is positioned at locations on a straight line extending radially from the center point of the design hole (i.e., the origin O) and passing through each of the multiple first laser irradiation points D1, and at additional locations between these locations on the straight line.

[0045] In S317, it is determined whether or not there is an undetected reflection point D2b at the second laser irradiation point D2. If there is an undetected reflection point D2b, it is assumed that the measurement target T has been found by expanding the search range, and the process proceeds to S318. If there is no undetected reflection point D2b, it is assumed that the measurement target T has still not been found even after expanding the search range, and the process proceeds to S319.

[0046] In S318, the local coordinate system is adjusted. In this embodiment, this adjustment is performed according to the procedure shown in the flowchart of Figure 5, similar to the adjustment performed in S313.

[0047] In S319, an error is detected. If an error is detected, the measurement described below will be postponed.

[0048] In S320, the measurement is performed under the adjusted local coordinate system, and then the measurement is terminated. In this measurement, the part to be measured T is scanned to measure its shape, and measurement values ​​related to the actual shape of the part to be measured T, such as its position or diameter, are calculated. In this embodiment, the position of the part to be measured T is the center position of the part to be measured T on the surface of the workpiece W. While a detailed explanation will be omitted, when measuring the shape of the part T to be measured, the inclination of the surface of the workpiece W is also measured simultaneously, and the shape measurement value of the part T to be measured is calculated taking into account the inclination of the surface of the workpiece W. For the sake of simplicity, the following explanation will assume a view from a direction perpendicular to the surface of the workpiece W.

[0049] Figure 5 shows the specific procedure for adjusting the local coordinate system when the hole is the part to be measured T (S313 and S318 in Figure 4). In the flowchart shown in Figure 5, in S411, the scanning center point CTR is set at a position shifted in the direction of the undetected reflection point D1b relative to the reference point C of the measurement target unit T (hereinafter referred to as the "measurement reference point"). Then, multiple laser scanning lines L1 passing through the set scanning center point CTR are set (see Figure 9).

[0050] Here, the "reference point" used as the basis for setting the scanning center point CTR, that is, the measurement reference point C, is the reference point assuming that the part to be measured T is in the normal position. The measurement reference point C is, for example, located at the center position of the hole which is the part to be measured T (in other words, the design value of the center position), and in this embodiment, the measurement reference point C coincides with the origin O.

[0051] The number of laser scanning lines L1 can be preset to a different number depending on the type of measurement target T.

[0052] In S412, the surface of the workpiece W is scanned along each of the multiple laser scanning lines L1 set in S411.

[0053] In S413, the edge point E1 of the part to be measured T is identified. In this embodiment, the part to be measured T is a hole, and the edge point E1 of the part to be measured T is the edge point of a hole such as a round hole or an elongated hole. The edge point E1 is identified by determining whether or not reflected laser light was detected from the laser irradiation point on each scanning line L1 when the surface of the workpiece W is scanned along multiple laser scanning lines L1. In other words, the edge point E1 is the surface portion of the workpiece W where the reflected laser light from the laser irradiation point on each scanning line L1 transitioned from a "detectable" state to a "undetectable" state, or the surface portion of the workpiece W where it transitioned from an "undetectable" state to a "detectable" state.

[0054] In S414, the shape of the part to be measured T is determined from the edge point E1, and the actual position, such as the center position of the part to be measured T, is calculated.

[0055] Figure 6 shows the details of the measurement process when measuring a stud bolt as the part to be measured T. In the flowchart shown in Figure 6, at S511, the side surface of the stud bolt is scanned in a direction that crosses the stud bolt, in other words, in a direction perpendicular to the central axis of the stud bolt, and the side surface of the stud bolt is measured. This scanning is performed multiple times, shifting in the direction in which the stud bolt protrudes from the surface of the workpiece W, in other words, in a direction parallel to the central axis of the stud bolt. This makes it possible to determine the position and shape of the stud bolt. In this embodiment, this scanning is performed three times.

[0056] In S512, it is determined whether the actual position of the stud bolt deviates from its normal position by a predetermined amount or more. If the position of the stud bolt deviates by a predetermined amount or more, it is determined that the measurement range needs to be changed, and the process proceeds to S513. If there is no deviation, or if the deviation is less than the predetermined amount, it is determined that the measurement range does not need to be changed, and the process bypasses S513 and proceeds to S514. The process in S512 may be omitted. In other words, the process may proceed to S513 regardless of the magnitude of the deviation in the actual position of the stud bolts; in other words, if there is even a minute deviation in the actual position of the stud bolts, the process may proceed.

[0057] In S513, the local coordinate system is adjusted. When the stud bolt is the measurement target part T, the adjustment of the local coordinate system is performed according to the procedure shown in the flowchart of Figure 7.

[0058] From S514 to S516, this measurement will be performed. Specifically, the procedure will be as follows.

[0059] In S514, a laser is shone onto the side of the stud bolt, and a point cloud of the laser is acquired on the side of the bolt.

[0060] In S515, a cylinder simulating a stud bolt or a part thereof is formed based on the point cloud acquired in S514.

[0061] S516 calculates the actual position, such as the center position of the stud bolts.

[0062] In S517, it is determined whether the actual position calculated in S516 is within the acceptable range of error relative to the normal position, i.e., the design value. If the center position is within the acceptable range, the calculated actual position (i.e., the measured value) is retained as measurement data and the measurement is terminated. If it is not within the acceptable range, the process proceeds to S518.

[0063] S518 determines that an error has occurred. If an error has occurred, information indicating that an error has occurred is displayed on display 103.

[0064] Figure 7 shows the specific procedure for adjusting the local coordinate system when the stud bolt is the part to be measured T (S513 in Figure 6). In the flowchart shown in Figure 7, step S611 adjusts the origin O of the local coordinate system with respect to the x and y directions. Specifically, based on the laser irradiation point D1 detected by S511, a circle or cylinder is formed that mimics the portion of the stud bolt's side surface that includes the laser irradiation point D1. The central axis of the formed circle or cylinder is then extended toward the surface of the workpiece W, and the intersection point between the surface of the workpiece W in its normal position and this extended central axis is calculated. The zero points in the x and y directions of the local coordinate system are then changed to the position of this intersection point.

[0065] In S612, the surface of the workpiece W is scanned along multiple scan lines extending radially from the modified zero point, and a point cloud of lasers aligned along these scan lines is acquired.

[0066] In S613, the projection plane of the stud bolt onto the surface of the workpiece W is extracted based on the point cloud acquired in S612. The projection plane of the stud bolt is obtained on the actual surface of the workpiece W and can be extracted from the arrangement of the acquired point cloud. Specifically, the boundary between the side surface of the stud bolt and the surface of the workpiece W is determined from the arrangement of the point cloud, and the projection plane of the stud bolt is extracted as a plane that includes this boundary.

[0067] In S614, the zero point in the z-direction of the local coordinate system is changed to a position on the projection plane, and this zero point is set to the origin O' of the adjusted local coordinate system. This completes the adjustment of the local coordinate system. Then, the process returns to the flowchart shown in Figure 6, and the actual measurement process from S514 onwards is performed.

[0068] The procedure for this measurement process (including coordinate system adjustment) when the measurement target part T is a round hole, elongated hole, square hole, or stud bolt will be explained in more detail below with reference to the schematic diagrams shown in Figures 8 to 30. For convenience, in the following explanation, the origin O of the three-dimensional coordinate system (x,y,z) is assumed to be the normal position of the part T being measured. The surface of the workpiece W lies on the xy plane where its position in the z direction of the coordinate system is 0, and it is assumed that there is no deviation from the normal position.

[0069] In Figures 8 through 30, the origin of the local coordinate system before adjustment is indicated by the symbol O, and the origin of the local coordinate system after adjustment is indicated by the symbol O'. Furthermore, the measurement target part T at the normal position is indicated by a dashed line, and the measurement target part T' actually formed on the workpiece W is indicated by a solid line.

[0070] (Measurement of round holes) This measurement process for circular holes is broadly divided into the following steps: determining whether or not there are any undetected reflection points (Figure 8), setting the scanning center point and scanning with a laser (Figure 9), detecting the edge points and changing the measurement reference point (Figure 10), and the actual measurement (Figure 11). Each of these steps is described below.

[0071] (Determination of whether or not there are points where reflection was not detected) As shown in Figure 8, multiple (eight in this embodiment) first laser irradiation points D1 (D1a, D1b) are set to surround the entire circumference of the circular hole T, which is the part to be measured. Then, the laser emitter 101a of the laser measuring machine 101 is driven to irradiate each of the first laser irradiation points D1 with a laser.

[0072] The laser receiver 101b of the laser measuring device 101 receives the reflected laser light and determines whether or not there are any undetected reflection points D1b at the first laser irradiation point D1. In the example shown in Figure 8, reflected laser light is detected at six of the first laser irradiation points D1 that are not at the location of the circular hole T' actually formed in the workpiece W (reflection detection points D1a), and the other two first laser irradiation points D1 that are at the location of the circular hole T' are identified as undetected reflection points D1b. In other words, the actual circular hole T' is not in its normal position, but is shifted to a position that includes the undetected reflection points D1b. From the reflection detection point D1a of the first laser irradiation point D1, it is possible to detect the tilt and positional displacement of the surface of the workpiece W in which the circular hole T is formed.

[0073] (Setting the scanning center point and scanning with a laser) To measure the actual circular hole T', as shown in Figure 9, the scanning center point CTR is set at a position shifted in the direction of the undetected reflection point D1b relative to the measurement reference point C (which in this embodiment coincides with the origin O) of the circular hole T. If there is one undetected reflection point D1b, the scanning center point CTR is set on the straight line connecting the measurement reference point C and the undetected reflection point D1b. If there are multiple undetected reflection points Dlb, the scanning center point CTR is set on a straight line starting from the measurement reference point C and passing between the undetected reflection points D1b at both ends in the circumferential direction.

[0074] Furthermore, multiple laser scan lines L1 (L1x, L1y) passing through the set scanning center point CTR are configured. In this embodiment, two laser scan lines that are mutually orthogonal at the scanning center point CTR are configured, specifically, a first scan line L1x extending in the x direction and a second scan line L1y extending in the y direction. Figure 9 schematically shows the first and second scan lines L1x and L1y, respectively, with dashed lines.

[0075] Then, the laser measuring device 101 scans the surface of the workpiece W along the first and second scanning lines L1x and L1y, respectively.

[0076] (Detection of edge points and modification of measurement reference points) As shown in Figure 10, the edge point E1(E1x, E1y) of the circular hole T' actually formed in the workpiece W is identified by scanning the surface of the workpiece W. The edge point E1(E1x, E1y) can be identified by whether or not reflected laser light is detected from the laser irradiation point on each of the two laser scan lines L1x and L1y when scanning the surface of the workpiece W along the two laser scan lines L1x and L1y. The edge point E1 is the edge of the circular hole T', and is the edge of the workpiece W surrounding the circular hole T'.

[0077] For example, when scanning along the first scan line L1x in the increasing direction of the x-axis, on the first scan line L1x, the proximal edge point E1x with respect to the origin O is identified as the point where the detected laser reflected light disappears, and the distal edge point E1x is identified as the point where the previously undetected laser reflected light appears. In other words, there is no surface of the workpiece W between the edge points E1x and the other edge point E1x, and the region sandwiched between these edge points E1x corresponds to the circular hole T'. The edge points E1x identified on the first scan line L1x correspond to the "first edge point" in this embodiment.

[0078] On the other hand, when scanning along the second scan line L1y in the increasing direction of the y-axis, on the second scan line L1y, the proximal edge point E1y with respect to the origin O is identified as the point where the detected laser reflected light disappears, and the distal edge point E1y is identified as the point where the previously undetected laser reflected light appears. In other words, similar to the edge point E1x, there is no surface of the workpiece W between the edge points E1y and the other edge point E1y, and the region sandwiched between these edge points E1y corresponds to the circular hole T'. The edge point E1y identified on the second scan line L1y corresponds to the "second edge point" in this embodiment.

[0079] Then, based on the positions of the identified edge points E1x and E1y, the position of the measurement reference point C is changed. Specifically, the midpoint M1x of the two edge points E1x and E1x identified on the first scan line L1x is calculated, and the midpoint M1y of the two edge points E1y and E1y identified on the second scan line L1y is calculated. The intersection point of a straight line passing through the midpoint M1x and extending in a direction parallel to the second scan line L1y (y-direction) and a straight line passing through the midpoint M1y and extending in a direction parallel to the first scan line L1x (x-direction) is calculated, and this intersection point is set as the measurement reference point for the round hole T', i.e., the changed reference point C'.

[0080] (This measurement) In this measurement, the circular hole T' is measured. In this embodiment, the center point of the circular hole T' is set as the measurement reference point C', and for this measurement, the measurement reference point of the modified circular hole T', i.e., the modified reference point C', is set to the origin O' of the local coordinate system.

[0081] As shown in Figure 11, multiple laser scan lines L2r are set, passing through the origin O' and arranged radially as a whole. The surface of the workpiece W is scanned along each of these multiple laser scan lines L2r. Edge points E2r of the circular hole T' are identified on each scan line L2r, and the actual position and shape of the circular hole T' are calculated based on the identified multiple edge points E2r.

[0082] Specifically, a circle is virtually created that represents the circular hole T', with multiple edge points E2r included on its outer circumference. Based on this created circle, the actual position and shape of the circular hole T', such as its center position C' and diameter φ, are calculated.

[0083] (Measurements related to modified examples) When the position of the part to be measured (round hole) T is significantly off from its normal position, the measurement should be performed according to the following procedure. This procedure is the process from S314 onwards as shown in Figure 4.

[0084] Among the procedures for when the positional deviation is large, the determination of whether or not there are undetected reflection points, setting the scanning center point, and scanning with a laser are shown in Figure 12, and the detection of edge points and the change of the measurement reference point are shown in Figure 13.

[0085] As shown in Figure 12, if the positional displacement of the circular hole T is large, reflected laser light is detected at all of the first laser irradiation points D1 (S311 in Figure 4), and all of the first laser irradiation points D1 are identified as reflection detection points D1a (negative determination in S312). To confirm whether the circular hole T' does not exist at the position of the first laser irradiation point D1 and whether the circular hole T' exists in the region enclosed by the first laser irradiation point D1, the laser is irradiated toward the origin O of the local coordinate system (S314). In the example shown in Figure 12, the circular hole T' is located far beyond the first laser irradiation point D1 from the origin O and is not within the region enclosed by the first laser irradiation point D1. Therefore, the laser irradiated towards the origin O is reflected off the surface of the workpiece W, and the centrally reflected light is detected.

[0086] Upon detection of the central reflected light (affirmative judgment in S315), the laser is directed towards each of the multiple second laser irradiation points D2 that are further from the origin O than the first laser irradiation point D1, and the reflected light is detected (S316).

[0087] Specifically, a greater number of second laser irradiation points D2 (16 points in this embodiment) are set outside the first laser irradiation point D1 in the radial direction of the circular hole T, so as to surround the circular hole T around its entire circumference. The positions of the second laser irradiation points D2 are on a straight line connecting the origin O and the first laser irradiation point D1. The interval i1 between the first laser irradiation point D1 and the second laser irradiation point D2 along this straight line can be set appropriately, taking into account the magnitude of any possible displacement that may occur in the position of the circular hole T'.

[0088] Of the second laser irradiation points D2, reflected laser light is detected at 15 points D2 that are not located at the position of the circular hole T' (reflection detection points D2a), and the one second laser irradiation point D2 located at the position of the circular hole T' is identified as the undetected reflection point D2b. In other words, the actual circular hole T' is shifted to a position that includes the undetected reflection point D2b.

[0089] Upon identifying the undetected reflection point D2b (affirmative judgment in S317), the scanning center point CTR is set at a position shifted in the direction of the undetected reflection point D2b relative to the measurement reference point C of the circular hole T. Then, two mutually orthogonal laser scanning lines (first scanning line L1x, second scanning line L1y) are set at the scanning center point CTR, and the surface of the workpiece W is scanned along the first and second scanning lines L1x and L1y, respectively.

[0090] The procedure for detecting the edge point and changing the measurement reference point is the same as the procedure described above, with reference to Figure 10.

[0091] Specifically, as shown in Figure 13, the edge point E1 (E1x, E1y) of the circular hole T' is identified. Then, the midpoint M1x of the two edge points E1x and E1x identified on the first scan line L1x is calculated, and the midpoint M1y of the two edge points E1y and E1y identified on the second scan line L1y is calculated. The intersection point of the line passing through the midpoint M1x and extending in the direction parallel to the second scan line L1y (y-direction) and the line passing through the midpoint M1y and extending in the direction parallel to the first scan line L1x (x-direction) is calculated, and this intersection point is set as the modification reference point C' of the circular hole T'. Then, the modified reference point C' is set to the origin O' of the local coordinate system, and the actual measurement of the circular hole T' is performed in the same manner as described earlier.

[0092] (Measurement of elongated holes) This measurement process for elongated holes is broadly divided into the following steps: determining whether or not there are undetected reflection points (Figure 14), setting the scanning center point and scanning with a laser (Figure 15), detecting edge points and changing the measurement reference point (Figure 16), correcting the inclination (Figure 17), and the actual measurement (Figure 18). Each of these steps is described below.

[0093] In this embodiment, "elongated hole" refers to a hole having an overall shape that is elongated in the direction of its major axis, with arcs at both ends in the direction of its major axis, and these arcs connected by a pair of sides extending in the direction of its major axis. Specifically, it refers to the shape illustrated by the dashed line in Figure 14. For the sake of explanation, the position of the elongated hole, which is the part to be measured T, is determined by its center position, and the origin O of the three-dimensional coordinate system (x,y,z) is considered the normal position of the elongated hole. The long axis direction of the elongated hole is the x direction, and the short axis direction is the y direction. The surface of the workpiece W lies on the xy plane where the position in the z direction of the coordinate system is 0, and it is assumed that there is no deviation from the normal position.

[0094] (Determination of whether or not there are points where reflection was not detected) As shown in Figure 14, multiple (eight in this embodiment) first laser irradiation points D1 (D1a, D1b) are set to surround the entire circumference of the elongated hole T, which is the part to be measured. Then, the laser emitter 101a of the laser measuring machine 101 is driven to irradiate each of the first laser irradiation points D1 with a laser, and it is determined whether or not there is a point D1b at the first laser irradiation point D1 where reflection was not detected. In the example shown in Figure 14, reflected laser light is detected at five of the first laser irradiation points D1 that are not located at the position of the elongated hole T' actually formed in the workpiece W (reflection detection points D1a), while the other three first laser irradiation points D1 located at the position of the elongated hole T' are identified as non-reflection detection points D1b. In other words, the actual elongated hole T' is not in its normal position, but is shifted to a position that includes the non-reflection detection points D1b.

[0095] (Setting the scanning center point and scanning with a laser) To measure the actual elongated hole T', as shown in Figure 15, a reference point REF is set at a position shifted in the direction of the undetected reflection point D1b relative to the measurement reference point C (which in this embodiment coincides with the origin O) of the elongated hole T. In this embodiment, since there are three undetected reflection points D1b, the reference point REF is set on a straight line passing between the undetected reflection points D1b at both ends of the circumferential direction, starting from the measurement reference point C.

[0096] Furthermore, scanning center points CTR (first scanning center point CTR1, second scanning center point CTR2) are set at positions separated from the set reference point REF in both the positive and negative x-axis directions, within the range that fits within the elongated hole T'. In this embodiment, the reference point REF is located midway between the first scanning center point CTR1 and the second scanning center point CTR2 (equally distanced from each of the first and second scanning center points CTR1 and CTR2), and the first and second scanning center points CTR1 and CTR2 are set at a distance from the reference point REF equivalent to half the length of the long side (a pair of sides extending in the direction of the long axis) of the elongated hole T. In other words, the first and second scanning center points CTR1 and CTR2 are set at positions corresponding to the center points of the semicircular shapes at both ends in the direction of the long axis of the elongated hole T, when the reference point REF is set to coincide with the origin O. In the example shown in Figure 15, the first scanning center point CTR1 is set on one side in the x-direction relative to the measurement reference point C, and the second scanning center point CTR2 is set on the other side in the x-direction relative to the measurement reference point C.

[0097] Then, multiple laser scanning lines L11r and L12r are set, extending radially from the first and second scanning center points CTR1 and CTR2, respectively. As shown in Figure 16, the laser scanning line L11r centered on the first scanning center point CTR1 intersects one arc ARC1 of the elongated hole T' actually formed in the workpiece W, and the laser scanning line L12r centered on the second scanning center point CTR2 intersects the other arc ARC2. Figures 15 and 16 schematically show the laser scanning lines L11r and L12r, respectively, with dashed lines.

[0098] Then, the laser measuring device 101 scans the surface of the workpiece W along the laser scanning lines L11r and L12r, respectively.

[0099] (Detection of edge points and modification of measurement reference points) As shown in Figure 16, the edge points E11r and E12r of the elongated hole T' actually formed in the workpiece W are identified.

[0100] To explain this in more detail with respect to the first scanning center point CTR1, when the surface of the workpiece W is scanned radially outward along the laser scanning line L11r from the first scanning center point CTR1, the first edge point E11r is identified as the point on the laser scanning line L11r where previously undetected reflected laser light appears. The first edge points E11r identified on each scanning line L11r are then arranged in an arc shape along one of the circular arcs ARC1.

[0101] The same applies to the second scanning center line CTR2. As a result of scanning the surface of the workpiece W along the laser scanning line L12r, the second edge point E12r is identified, which is arranged in an arc shape along the other arc ARC2.

[0102] Then, based on the identified first and second edge points E11r and E12r, the position of the measurement reference point C is changed. Specifically, an arc passing through the identified first edge point E11r (corresponding to the "first arc") is created on the laser scan line L11r, and the center C11 of this arc is calculated. At the same time, an arc passing through the identified second edge point E12r (corresponding to the "second arc") is created on the laser scan line L12r, and the center C12 of this arc is calculated.

[0103] Create a line segment with these two centers C11 and C12 as its endpoints, and calculate the midpoint of this line segment. Then, set this midpoint as the measurement reference point for the elongated hole T', i.e., the modification reference point C'.

[0104] (Tilt correction) The angle θ that a line segment with its endpoints C11 and C12 makes with respect to the x-axis, or in other words, the angle θ that this line segment makes with respect to the major axis of the elongated hole T in its normal position, is used to detect the inclination of the elongated hole T', and the coordinate system (x,y,z) is corrected according to this inclination of the elongated hole T'.

[0105] Specifically, as shown in Figure 17, a straight line is set that passes through the reference point C' and extends parallel to the x-axis, and the orientation of the x-axis and y-axis is adjusted so that the angle θ that this straight line makes with the line segment C11-C12 is 0 degrees. Then, under the adjusted coordinate system (x', y', z), the modified reference point C' is set to the origin O' of this local coordinate system, and the actual measurement of the elongated hole T' is performed.

[0106] (This measurement) In this measurement, the elongated hole T' is measured. In this embodiment, the center point of the elongated hole T' is set as the measurement reference point C', and for this measurement, the measurement reference point of the modified elongated hole T', i.e., the modified reference point C', is set to the origin O' of the local coordinate system.

[0107] As shown in Figure 18, a laser scan line L2y is set that passes through the origin O' and is perpendicular to the pair of long sides, and two laser scan lines L2y are set that are shifted in the x direction from this laser scan line L2y. These three laser scan lines L2y are parallel to each other. Furthermore, multiple laser scan lines L21r are set that radiate from the center C11' of one arc ARC1, and multiple laser scan lines L22r are set that radiate from the center C12' of the other arc ARC2.

[0108] Then, the surface of the workpiece W is scanned along the laser scanning lines L2y, L21r, and L22r, and the edge points E2y, E21r, and E22r of the elongated hole T' are identified on each of the scanning lines L2y, L21r, and L22r.

[0109] Furthermore, the actual position and shape of the elongated hole T' are measured based on the identified edge points E2y, E21r, and E22r. Specifically, arcs passing through edge point L21r and L22r are created, and these two arcs are connected by a line segment passing through edge point E2y to virtually create an elongated hole that mimics the elongated hole T'. Based on the created elongated hole, the actual position and shape of the elongated hole T', including its center position C' and dimensions, are calculated.

[0110] (Measurements related to modified examples) When the position of the part to be measured (elongated hole) T is significantly off from its normal position, the measurement should be performed according to the following procedure.

[0111] Among the procedures for when the positional deviation is large, the determination of whether or not there are undetected reflection points, setting the scanning center point, and scanning with a laser are shown in Figure 19, and the detection of edge points and the change of the measurement reference point are shown in Figure 20.

[0112] As shown in Figure 19, if the displacement of the elongated hole T is large, reflected laser light is detected at all of the first laser irradiation points D1, and all of the first laser irradiation points D1 are identified as reflection detection points D1a. To confirm whether the elongated hole T' does not exist at the position of the first laser irradiation point D1 and whether the elongated hole T' exists in the region enclosed by the first laser irradiation point D1, the laser is irradiated towards the origin O of the local coordinate system. In the example shown in Figure 19, the elongated hole T' is located far beyond the origin O and beyond the first laser irradiation point D1, and is not within the region enclosed by the first laser irradiation point D1. Therefore, the laser irradiated towards the origin O is reflected off the surface of the workpiece W, and the centrally reflected light is detected.

[0113] Upon detection of the central reflected light, the laser is directed towards each of the multiple second laser irradiation points D2 that are further from the origin O than the first laser irradiation point D1, and the reflected light is detected. Specifically, a greater number of second laser irradiation points D2 (16 points in this embodiment) are set to surround the entire circumference of the elongated hole T, at a position further from the origin O than the first laser irradiation point D1. The positions of the second laser irradiation points D2 are between the straight line passing through the origin O and the first laser irradiation point D1, and the second laser irradiation points D2 positioned on this straight line. The interval i2 between the first laser irradiation point D1 and the second laser irradiation points D2 along this straight line can be appropriately set considering the magnitude of the possible displacement that may occur in the position of the elongated hole T'.

[0114] Of the second laser irradiation points D2, reflected laser light is detected at 15 points D2 that are not located at the position of the elongated hole T' (reflection detection points D2a), and the one second laser irradiation point D2 located at the position of the elongated hole T' is identified as the undetected reflection point D2b. In other words, the actual elongated hole T' is shifted to a position that includes the undetected reflection point D2b.

[0115] Upon identifying the point D2b where reflection was not detected, a reference point REF is set at a position shifted in the direction of the point D2b relative to the measurement reference point C of the elongated hole T. In this embodiment, this point REF is set on a straight line passing through the origin O and the point D2b. Based on this reference point REF, two scanning center points CTR (first scanning center point CTR1, second scanning center point CTR2) are set. Then, laser scanning lines L11r and L12r are set, extending radially from the first and second scanning center points CTR1 and CTR2, respectively, and the surface of the workpiece W is scanned along the first and second scanning lines L1x and L1y, respectively.

[0116] The procedure for detecting the edge point and changing the measurement reference point is the same as the procedure described above, with reference to Figure 16.

[0117] Specifically, as shown in Figure 20, the edge points of the elongated hole T' (first edge point E11r, second edge point E12r) are identified. Then, the center C11 of the arc ARC1 that includes the first edge point E11r on its outer circumference is calculated, and the center C12 of the arc ARC2 that includes the second edge point E12r on its outer circumference is calculated. The midpoint of the line segment connecting these centers C11 and C12 is calculated, and this midpoint is set as the modification reference point C' of the elongated hole T'. Then, the modified reference point C' is set to the origin O' of the local coordinate system, and the main measurement of the elongated hole T' is performed.

[0118] (Measurement of square holes) This measurement process for rectangular holes is broadly divided into the following steps: determining whether there are any undetected reflection points (Figure 21), setting the scanning center point and scanning with a laser (Figure 22), detecting edge points and changing the measurement reference point (Figure 23), correcting the tilt (Figure 24), and the actual measurement (Figure 25). Each of these steps is described below.

[0119] In this embodiment, a "square hole" refers to a hole having a pair of sides extending in the direction of the major axis (long side) and a pair of sides extending in the direction of the minor axis (short side), and having an overall rectangular shape that is long in the direction of the major axis. Specifically, it refers to the shape illustrated by the dashed line in Figure 21. Here, a "square hole" is not limited to one in which a corner is interposed between the long side and the short side, but may also be one in which a circular arc is interposed.

[0120] (Determination of whether or not there are points where reflection was not detected) As shown in Figure 21, multiple (eight in this embodiment) first laser irradiation points D1 (D1a, D1b) are set to surround the entire circumference of the rectangular hole T, which is the part to be measured. Then, the laser emitter 101a of the laser measuring machine 101 is driven to irradiate each of the first laser irradiation points D1 with a laser, and it is determined whether or not there are any undetected reflection points D1b at the first laser irradiation points D1. In the example shown in Figure 21, the reflected laser light is detected at five of the first laser irradiation points D1 that are not located at the positions of the rectangular hole T' actually formed in the workpiece W (reflection detection points D1a), and the other three first laser irradiation points D1 located at the positions of the rectangular hole T' are identified as undetected reflection points D1b. In other words, the actual rectangular hole T' is shifted to a position that includes the undetected reflection points D1b.

[0121] (Setting the scanning center point and scanning with a laser) To measure the actual rectangular hole T', a reference point REF is set at a position shifted in the direction of the undetected reflection point D1b relative to the measurement reference point C (which in this embodiment coincides with the origin O) of the rectangular hole T, as shown in Figure 22. In this embodiment, since there are three undetected reflection points D1b, the reference point REF is set on a straight line passing between the undetected reflection points D1b at both ends of the circumferential direction, starting from the measurement reference point C.

[0122] Furthermore, a first scan line L1x is set, which passes through the set reference point REF and extends in the x-direction (corresponding to the long axis direction of the rectangular hole T in the normal position), and two second scan lines L1y are set, which extend in the y-direction perpendicular to the laser scan line L1x from scan center points CTR (first scan center point CTR1, second scan center point CTR2), which are set at positions separated in the positive and negative x-directions, respectively, within the range that fits within the rectangular hole T' from the reference point REF. In this embodiment, the reference point REF is located at an equal distance from the first scanning center point CTR1 and the second scanning center point CTR2, respectively. The distance from each of the first and second scanning center points CT1 and CTR2 to the reference point REF is equal to or shorter than half the length of the long side of the rectangular hole T. In the example shown in Figure 22, the distance between the first scanning center point CTR1 and the second scanning center point CTR2 is equal to or shorter than half the length of the long side of the rectangular hole T. The first scanning center point CTR1 is set on one side in the x-direction with respect to the measurement reference point C, and the second scanning center point CTR2 is set on the other side in the x-direction with respect to the measurement reference point C.

[0123] In other words, we set up a laser scan line L1x that passes through the first and second scanning center points CTR1 and CTR2 and extends in the x direction (corresponding to the "first scan line"), a laser scan line L11y that passes through the first scanning center point CTR1 and extends perpendicular to the first scan line L1x (corresponding to the "second scan line"), and a laser scan line L12y that passes through the second scanning center point CTR2 and extends perpendicular to the first scan line L1x (corresponding to the "third scan line"). The first scan line L1x intersects the short side of the rectangular hole T', and the second and third scan lines L11y and L12y intersect the long side of the rectangular hole T'. Figure 22 schematically shows the laser scan lines L1x, L11y, and L12y, respectively, with dashed lines.

[0124] Then, the laser measuring device 101 scans the surface of the workpiece W along the laser scanning lines L1x, L11y, and L12y, respectively.

[0125] (Detection of edge points and modification of measurement reference points) As shown in Figure 23, the edge points E1x, E11y, and E12y of the elongated hole T' actually formed in the workpiece W are identified.

[0126] To explain this in more detail with respect to the first scan line L1x, when the surface of the workpiece W is scanned in the positive x-axis direction along the first scan line L1x, a pair of first edge points E1x are identified on the first scan line L1x as the point where the detected laser reflected light disappears and the point where the undetected laser reflected light appears.

[0127] The same applies to the second and third scanning lines L11y and L12y. When the surface of the workpiece W is scanned in the positive direction of the y-axis along the second and third scanning lines L11y and L12y, a pair of second edge points E11y and a pair of third edge points E12y are identified on each scanning line L11y and L12y as points where the detected laser reflected light disappears and points where the undetected laser reflected light appears, respectively.

[0128] Then, based on the identified edge points E1x, E11y, and E12y, the position of the measurement reference point C is changed. Specifically, the intersection point of a straight line (corresponding to the "first reference line") passing through the midpoint M1x of the pair of first edge points E1x and perpendicular to the first scan line L1x, and a line segment (corresponding to the "second reference line") connecting the midpoint M11y of the pair of second edge points E11y and the midpoint M12y of the pair of third edge points E12y is calculated, and this intersection point is set as the measurement reference point for the square hole T', i.e., the changed reference point C'.

[0129] (Tilt correction) The angle θ that the line segment with its endpoints M11y and M12y makes with respect to the x-axis, or in other words, the angle θ that this line segment makes with respect to the major axis of the square hole T in its normal position, is used to detect the inclination of the square hole T', and the coordinate system (x,y,z) is corrected according to this inclination of the square hole T'.

[0130] Specifically, as shown in Figure 24, a straight line is set that passes through the modification reference point C' and extends parallel to the x-axis, and the orientation of the x-axis and y-axis is adjusted so that the angle θ that this straight line makes with the line segment M11y-M12y is 0 degrees. Then, under the adjusted coordinate system (x',y',z), the modified reference point C' is set to the origin O' of this local coordinate system, and the actual measurement of the rectangular hole T' is performed.

[0131] (This measurement) In this measurement, the square hole T' is measured. In this embodiment, the center point of the square hole T' is set as the measurement reference point C', and for this measurement, the measurement reference point of the square hole T' after modification, i.e., the modification reference point C', is set to the origin O' of the local coordinate system.

[0132] As shown in Figure 25, multiple laser scan lines L2x extending in the x-direction and multiple laser scan lines L2y extending in the y-direction are set. The laser scan lines L2x in the x-direction are parallel to each other and spaced equally apart, and the laser scan lines L2y in the y-direction are parallel to each other and spaced equally apart. The laser scan lines L2x in the x-direction are perpendicular to the short side of the rectangular hole T', and the laser scan lines L2y in the y-direction are perpendicular to the long side of the rectangular hole T'. The number of laser scan lines L2x can be appropriately set so that they extend in the x-direction, intersecting each of the opposing short sides, and spaced apart in the y-direction, excluding the portion connecting the short and long sides of the rectangular hole T' (shown as an arc in Figure 25). Similarly, the number of laser scan lines L2y can be appropriately set so that they extend in the y-direction, intersecting each of the opposing long sides, and spaced apart in the x-direction, excluding the portion connecting the short and long sides of the rectangular hole T'.

[0133] Then, the surface of the workpiece W is scanned along the laser scanning lines L2x and L2y, respectively, and the edge points E2x and E2y of the rectangular hole T' are identified on each scanning line L2x and L2y.

[0134] Furthermore, the actual position and shape of the rectangular hole T' are calculated based on the identified edge points E2x and E2y. Specifically, the shorter side of the rectangular hole T' is created on a straight line passing through the edge points E2x aligned in the y direction, and the longer side of the rectangular hole T' is created on a straight line passing through the edge points E2y aligned in the x direction. By connecting the created shorter and longer sides, a rectangular hole that mimics the rectangular hole T' is virtually created. Based on the created rectangular hole, the actual position and shape of the rectangular hole T', including its center position C' and dimensions, are calculated.

[0135] (Measurements related to modified examples) When the position of the part to be measured (square hole) T is significantly off from the normal position, the measurement should be performed according to the following procedure.

[0136] Among the procedures for when the positional deviation is large, the determination of whether or not there are undetected reflection points, setting the scanning center point, and scanning with a laser are shown in Figure 26, and the detection of edge points and the change of the measurement reference point are shown in Figure 27.

[0137] As shown in Figure 26, if the displacement of the rectangular hole T is large, reflected laser light is detected at all of the first laser irradiation points D1, and all of the first laser irradiation points D1 are identified as reflection detection points D1a. To confirm whether the rectangular hole T does not exist at the position of the first laser irradiation point D1 and whether the rectangular hole T' exists in the region enclosed by the first laser irradiation point D1, the laser is irradiated towards the origin O of the local coordinate system. In the example shown in Figure 26, the rectangular hole T' is located far from the origin O, beyond the first laser irradiation point D1, and is not within the region enclosed by the first laser irradiation point D1. Therefore, the laser irradiated towards the origin O is reflected off the surface of the workpiece W, and the centrally reflected light is detected.

[0138] Upon detection of the central reflected light, the laser is directed towards each of the multiple second laser irradiation points D2 that are further from the origin O than the first laser irradiation point D1, and the reflected light is detected. Specifically, a greater number of second laser irradiation points D2 (16 points in this embodiment) are set to surround the entire circumference of the rectangular hole T, at a position further from the origin O than the first laser irradiation point D1. The positions of the second laser irradiation points D2 lie on the straight line connecting the origin O and the first laser irradiation point D1. The interval i3 between the first laser irradiation point D1 and the second laser irradiation points D2 along this straight line can be set appropriately, taking into account the magnitude of any possible displacement in the position of the rectangular hole T'.

[0139] Of the second laser irradiation points D2, reflected laser light is detected at 14 points D2 that are not located at the position of the rectangular hole T' (reflection detection points D2a), and the two points D2 that are located at the position of the rectangular hole T' are identified as undetected reflection points D2b. In other words, the actual rectangular hole T' is shifted to a position that includes the undetected reflection points D2b.

[0140] Upon identifying the point D2b where reflection was not detected, a reference point REF is set at a position shifted in the direction of the point D2b relative to the measurement reference point C of the rectangular hole T. In this embodiment, the reference point REF is set on a straight line passing between the two points D2b, starting from the origin O. Based on this reference point REF, two scanning center points CTR (first scanning center point CTR1, second scanning center point CTR2) are set. Then, a first scanning line L1x is set that extends in the x direction passing through the first and second scanning center points CTR1 and CTR2, and second and third scanning lines L11y and L12y are set that are orthogonal to the first scanning line L1x at the first and second scanning center points CTR1 and CTR2, respectively. The surface of the workpiece W is scanned along the first, second and third scanning lines L1x, L11y and L12y, respectively.

[0141] The procedure for detecting the edge point and changing the measurement reference point is the same as the procedure described above, with reference to Figure 23.

[0142] Specifically, as shown in Figure 27, the edge points of the rectangular hole T' (first edge point E1x, second edge point E11y, and third edge point E12y) are identified. Then, based on these edge points E1x, E11y, and E12y, a straight line passing through the midpoint M1x (first reference line) and a line segment connecting the midpoints M11y and M12y (second reference line) are created, and the intersection point of these reference lines is calculated. This intersection point is then set as the modification reference point C' of the rectangular hole T'. Then, the modified reference point C' is set to the origin O' of the local coordinate system, and the main measurement of the square hole T' is performed.

[0143] (Measurement of stud bolts) The process for stud bolts includes coordinate system adjustment and the main measurement process. The coordinate system adjustment process is broadly divided into stud bolt detection (Figure 28), cylinder extraction (Figure 29), and bolt center modification (Figure 30). The following describes each step of the coordinate system adjustment process.

[0144] In Figures 28 to 30, the x and y directions of the local coordinate system are set parallel to the surface Wa of the workpiece W. Then, the z direction of the local coordinate system is set perpendicular to the surface Wa of the workpiece W. The stud bolt T in the normal position is installed perpendicular to the surface Wa of the workpiece W, and its central axis A extends in the z direction and is perpendicular to the surface Wa.

[0145] In Figures 28 to 30, (a) shows the stud bolt T viewed in the y-direction, specifically in the negative direction along the y-axis, and (b) shows the stud bolt T viewed in the z-direction, specifically in the negative direction along the z-axis.

[0146] In each of these figures, the stud bolt T in its normal position is shown by a dashed line, and the stud bolt T' actually installed on the workpiece W, i.e., the stud bolt T' in its actual position, is shown by a solid line. Thus, in the following explanation, we will assume a case where there is a deviation in the position of the stud bolt T' from its normal position (stud bolt T). Figure 28 shows the state where deviations occur in the x, y, and z directions, specifically, when deviations occur in the positive x-axis, negative y-axis, and positive z-axis directions.

[0147] (Detection of stud bolts) As shown in Figure 28, the laser is irradiated onto the side of the stud bolt T by scanning along multiple scan lines that extend perpendicular to the central axis of the stud bolt T, in this embodiment, in the negative direction of the y-axis. The reference point for determining the direction of the scan lines is the central axis of the stud bolt T in its normal position, i.e., the z-axis before adjustment, and the laser is actually irradiated onto the side of the stud bolt T' that is actually installed in the workpiece W. Figure 28(a) shows the laser irradiation direction RD, and Figure 28(b) shows the laser scanning direction SC. The laser irradiation direction RD is the laser propagation direction and extends in the negative direction of the x-axis.

[0148] Based on the laser irradiation point D1 where the reflected laser light is detected from the side of the stud bolt T', the stud bolt T' is detected, and it is determined whether or not there is a deviation from its normal position (stud bolt T) at the detected stud bolt's position. In this embodiment, as shown in Figure 28(b), the amount of deviation in the xy plane is determined.

[0149] (Extraction of cylinder) As shown in Figure 29(a), a cylindrical CY is formed that mimics the portion of the side surface of the stud bolt T' that includes the laser irradiation point D1, based on the laser irradiation point D1 where the reflected light of the laser is detected. In this embodiment, a point cloud of the laser irradiation points D1, which are arranged in the circumferential direction centered on the z-axis Az, is extracted on each scan line to create the cylindrical CY. Figures 29(a) and (b) schematically show the cylindrical CY with a thick dashed line.

[0150] The central axis of the formed cylinder CY is extended toward the surface of the workpiece W, and the intersection point between the surface of the workpiece W in the normal position and this extended central axis is calculated. Here, the surface of the workpiece W in the normal position is at the 0 point in the z direction. Then, as shown in Figure 29(b), the 0 points in the x and y directions of the local coordinate system are changed to the position of this intersection point. The changed 0 point corresponds to the "reference point" when the stud bolt is the part to be measured.

[0151] (Modification of the bolt center) As shown in Figure 30(b), the surface Wa of the workpiece W is scanned along multiple scan lines extending radially from the modified zero point (i.e., the zero point in the x and y directions), and a point cloud of laser irradiation points D2 aligned along each of these scan lines is obtained.

[0152] Then, based on these point clouds, the projection plane of the stud bolt T' onto the surface Wa of the workpiece W is extracted. Since the surface on which the laser irradiation point D2 is formed is the surface Wa of the workpiece W on which the stud bolt T' is actually installed (the actual surface of the workpiece W), the projection plane is located at the position of point 0 in the z direction.

[0153] As shown in Figure 30(a), the zero point in the z-direction of the local coordinate system is changed to a position on the projection plane, and this zero point is set to the origin O' of the adjusted local coordinate system. This completes the adjustment of the local coordinate system.

[0154] After completing the coordinate system adjustment process, the process moves on to the main measurement targeting the stud bolt T', and the main measurement is carried out.

[0155] In this measurement, for example, the stud bolt T' is scanned in the y and z directions to create a cylinder that simulates the entire stud bolt T'. Based on the created cylinder, the actual position and shape of the stud bolt T', such as its center position C', length, and diameter, are calculated.

[0156] (Explanation of action and effects) The effects obtained by this embodiment will be described below.

[0157] First, a laser is shone towards multiple laser irradiation points D1 surrounding the part of the workpiece W to be measured (for example, a hole). If there are undetected reflection points D1b at these multiple laser irradiation points D1, a scanning center point CTR is set at a position shifted relative to the reference point C of the part of the workpiece T in the direction of the undetected reflection points D1b. Then, the laser is scanned along multiple scan lines L1 passing through the scanning center point CTR to detect multiple edge points E1 of the part of the workpiece T. Based on the positions of the multiple edge points E1, the position of the reference point C is updated, and the part of the workpiece T is measured using the updated reference point C', which is the updated reference point.

[0158] This makes it possible to adjust the reference point C using the laser measuring machine 101 to eliminate or mitigate the deviation if the position of the part T to be measured in the workpiece W deviates from its normal position, i.e., the design position, without the need for special or additional equipment.

[0159] Secondly, the circular hole formed in the workpiece W is designated as the measurement target T, and the laser is scanned along multiple scanning lines, including mutually orthogonal first and second scanning lines L1x and L1y (Figure 9).

[0160] This makes it possible to quickly adjust any misalignment in the position of the circular hole in the workpiece W while minimizing the number of laser irradiations.

[0161] Thirdly, when the part to be measured T is a round hole, a pair of first edge points E1x detected on the first scan line L1x and a pair of second edge points E1y detected on the second scan line L1y are identified as multiple edge points E1, and the updated reference point C' is set as a position that is equal in distance from each of the pair of first edge points E1x and the pair of second edge points E1y (Figure 10).

[0162] This makes it possible to more accurately adjust for any misalignment in the position of the circular hole, which is the part to be measured (T).

[0163] Fourth, the elongated hole formed in the workpiece W is designated as the measurement target T. After determining whether or not there are any undetected reflection points D1b, the first scanning center point CTR1 is set on one side of the reference point C with respect to the long axis direction of the elongated hole, and the second scanning center point CTR2 is set on the other side. The laser is scanned radially from the first scanning center point CTR1 and the second scanning center point CTR2, respectively, to detect the first and second edge points E11r and E12r of the measurement target T, which are arranged in an arc shape, as multiple edge points E1. Based on the positions of the first and second edge points E11r and E12r, respectively, the position of the reference point C is changed (Figures 15 and 16).

[0164] This makes it possible to detect and adjust any misalignment in the position of the elongated holes in the workpiece W.

[0165] Fifth, we define an arc (first arc) ARC1 that includes the first edge point E11r on its outer circumference, and an arc (second arc) ARC2 that includes the second edge point E12r on its outer circumference, and set the update reference point C' as the midpoint between the center C11 of the first arc ARC1 and the center C12 of the second arc ARC2 (Figure 16).

[0166] This makes it possible to more accurately detect and adjust any misalignment in the position of the elongated hole, which is the part to be measured (T).

[0167] Sixth, the orientation of the workpiece W is corrected based on the slope of the line segment (i.e., the reference line) connecting the center C11 of the first arc ARC1 and the center C12 of the second arc ARC2 (Figure 17).

[0168] This makes it possible to understand deviations in the orientation of the workpiece W in addition to its position, and by correcting the orientation of the workpiece W prior to the main measurement of the measurement target T, it becomes possible to perform the measurement more accurately.

[0169] Seventh, the rectangular hole formed in the workpiece W is used as the measurement target T, and the laser is scanned along a plurality of scan lines, including a first scan line L1x and second and third scan lines L11y and L12y, which are orthogonal to the first scan line L1x, respectively (Figure 22).

[0170] This makes it possible to detect and adjust for any misalignment in the position of the square hole in the workpiece W, including misalignment in the rotational direction.

[0171] Eighth, when the part to be measured T is a square hole, a pair of first edge points E1x detected on the first scan line L1x, a pair of second edge points E11y detected on the second scan line L11y, and a pair of third edge points E12y detected on the third scan line L12y are identified as multiple edge points E1, and an updated reference point C' is set as the intersection of a straight line (first reference line) that passes through the midpoint M1x of the pair of first edge points E1x and is perpendicular to the first scan line L1x, and a line segment (second reference line) that connects the midpoint M11y of the pair of second edge points E11y and the midpoint M12y of the pair of third edge points E12y (Figure 23).

[0172] This allows for the detection of misalignment in the position of the rectangular hole (the part T being measured), as well as the detection of misalignment in the rotational direction, enabling more accurate adjustment.

[0173] Ninth, the orientation of the workpiece W is corrected based on the slope of the second reference line (Figure 24).

[0174] This allows for more accurate measurement by correcting the orientation of the workpiece W prior to the main measurement of the part T to be measured.

[0175] Tenth, if reflected laser light is detected at all of the multiple laser irradiation points D1, the laser is irradiated toward the measurement reference point C. If reflected laser light is still detected at the measurement reference point C, the multiple laser irradiation points D2 are changed to positions further away from the measurement reference point C, the laser is irradiated toward the changed laser irradiation points D2, and the presence or absence of points D2b where reflection was not detected is determined again.

[0176] This makes it possible to detect and adjust for any significant deviation in the position of the measurement target T using existing equipment.

[0177] Laser irradiation is not limited to the measurement reference point C; it can also be performed at appropriate positions on the surface of the workpiece W within the area enclosed by multiple laser irradiation points D1. For example, if the part to be measured T is a circular hole and the measurement reference point C is set to the origin O of the local coordinate system, the laser is irradiated towards a position where the distance from the origin O is less than or equal to the radius of the circular hole T.

[0178] Eleventh, in this embodiment, the part to be measured T that protrudes from the surface of the workpiece W is measured by a laser measuring instrument 101. The laser measuring instrument 101 scans the side surface of the part to be measured T along a plurality of first scanning lines (indicated by arrow SC) that extend perpendicular to the direction in which the part to be measured T protrudes, and a reference point is identified where the central axis of the part to be measured T intersects the surface based on the laser irradiation point D1 where the reflected light of the laser is detected (Figure 29). Then, the laser is scanned along a plurality of second scanning lines that extend radially from this reference point to acquire a point cloud of laser irradiation points D2, and based on this point cloud, the projection plane of the part to be measured T' is calculated, a reference point is set on the projection plane, and the part to be measured T' is measured based on the reference point (Figure 30).

[0179] This makes it possible to automatically adjust for any displacement in the position of the part T being measured, such as when the part T is a protruding object like a stud bolt, using the laser measuring device 101.

[0180] The automatic measuring device 1 according to this embodiment is cylindrical and can be suitably used for measuring a part T to be measured that protrudes perpendicularly to the surface, and is particularly suitable for measuring stud bolts fixed to a workpiece W.

[0181] The embodiments described above are illustrative and do not limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, or modifications can be made without departing from the spirit of the invention. These embodiments or their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0182] W...workpiece, 1...automatic measuring device, 101...laser measuring machine, 101a...laser transmitter, 101b...laser receiver, 102...controller, 102a...CPU, 102b...storage unit, 103...display.

Claims

1. Equipped with a laser measuring device, The laser measuring device irradiates a laser towards multiple laser irradiation points surrounding the part of the workpiece to be measured. It is determined whether there are any points among the plurality of laser irradiation points where reflected light from the laser is not detected, other than the points where reflected light from the laser is detected. If there are points where reflection is not detected, the scanning center point is set at a position shifted in the direction of the points where reflection is not detected relative to the reference point of the measurement target unit. The surface of the workpiece is scanned along multiple scan lines passing through the scanning center point to detect multiple edge points of the part to be measured. Based on the positions of the aforementioned multiple edge points, the position of the reference point is changed. An automatic measuring device that measures the part to be measured using the modified reference point, which is the modified reference point.

2. The automatic measuring device according to claim 1, wherein the part to be measured is a hole formed in the workpiece.

3. The part to be measured is a round hole, The automatic measuring device according to claim 2, wherein the plurality of scan lines include a first scan line and a second scan line that intersect each other.

4. The plurality of edge points include a pair of first edge portions detected on the first scan line and a pair of second edge portions detected on the second scan line. The automatic measuring device according to claim 3, wherein the update reference point is set as a position that is equal in distance from each of the pair of first edge points and the pair of second edge points.

5. The part to be measured is a rectangular hole, The automatic measuring device according to claim 2, wherein the plurality of scan lines include a first scan line and second and third scan lines that intersect the first scan line, respectively.

6. The plurality of edge points include a pair of first edge points detected on the first scan line, a pair of second edge points detected on the second scan line, and a pair of third edge points detected on the third scan line. The automatic measuring device according to claim 5, wherein the update reference point is set as the intersection of a first reference line passing through the midpoints of the pair of first edge points and intersecting the first scan line, and a second reference line connecting the midpoints of the pair of second edge points and the midpoints of the pair of third edge points.

7. The automatic measuring device according to claim 6, which corrects the orientation of the workpiece based on the slope of the second reference line.

8. The part to be measured is an elongated hole, After determining the points where reflection was not detected, the first scanning center point is set on one side of the reference point with respect to the long axis direction of the elongated hole, and the second scanning center point is set on the other side. The surface of the workpiece is scanned along laser scanning lines extending radially from the first scanning center point and the second scanning center point, respectively, to detect the first and second edge points of the measurement target portion, which are arranged in an arc shape, as the plurality of edge points. The automatic measuring device according to claim 2, which updates the position of the reference point based on the positions of the first and second edge points, respectively.

9. A first circular arc or a first circle that includes part of the first circular arc, on which the first edge points are aligned on the outer circumference, and a second circular arc or a second circle that includes part of the second circular arc, on which the second edge points are aligned on the outer circumference, are defined. The automatic measuring device according to claim 8, wherein the update reference point is set as the midpoint between the center of the first arc or first circle and the center of the second arc or second circle.

10. The automatic measuring device according to claim 9, which corrects the orientation of the workpiece based on the inclination of a reference line connecting the center of the first arc or first circle and the center of the second arc or second circle.

11. The automatic measuring device according to any one of claims 1 to 10, wherein the reference point is the center point of the part to be measured.

12. The automatic measuring device according to claim 11, wherein, if reflected light of the laser is detected at all of the plurality of laser irradiation points, the laser is irradiated onto the region surrounded by the plurality of laser irradiation points, and, provided that reflected light of the laser is still detected in this region, the plurality of laser irradiation points are changed to positions at a wider distance from the reference point, the laser is irradiated toward the changed laser irradiation points, and the presence or absence of points where reflection was not detected is determined again.

13. The automatic measuring device according to claim 12, wherein when reflected light of the laser is detected at all of the plurality of laser irradiation points, the laser is irradiated toward the reference point, and on the condition that reflected light of the laser is still detected at the reference point, the plurality of laser irradiation points are changed to positions at a greater distance from the reference point.

14. Equipped with a laser measuring device, An automatic measuring device for measuring a part to be measured that protrudes from the surface of a workpiece using the laser measuring machine, The laser measuring device scans the part to be measured along a plurality of first scanning lines extending in a direction transverse to the part to be measured. Based on the laser irradiation point on the first scanning line where the reflected laser light is detected, a reference point is identified where the central axis of the part to be measured intersects the surface. The surface of the workpiece is scanned along a plurality of second scanning lines extending radially from the aforementioned reference point to acquire the laser point cloud. Based on the point cloud, the projection plane of the part to be measured relative to the surface of the workpiece is calculated, and the reference point is set on the projection plane. An automatic measuring device that measures the part to be measured based on the aforementioned reference point.

15. The automatic measuring device according to claim 14, wherein the part to be measured is cylindrical and protrudes perpendicularly from the surface of the workpiece.

16. The automatic measuring device according to claim 15, wherein the part to be measured is a stud bolt fixed to the workpiece.

Images