Grinding system, grinding method, and method for manufacturing steel product

Abstract

The grinding system comprises: a shape measuring device for measuring the three-dimensional shape and posture of a workpiece to be ground; a detection device for detecting the position and shape of a grinding target part on the surface of the workpiece to be ground; a grinding device (6) provided with a grinding tool for grinding the part to be ground; a moving mechanism for moving the workpiece relative to the shape measuring device and the grinding device; a grinding tool control device (5) for generating a trajectory of a grinding tool for grinding the grinding target part on the basis of the three-dimensional shape and orientation of the workpiece measured by the shape measurement device and the position and shape of the grinding target part detected by the detection device, and controlling the grinding device so that the grinding tool moves along the trajectory; and a movement mechanism control device (12) for controlling the movement mechanism so that the workpiece moves relative to the shape measuring device and the grinding device when the workpiece is measured by the shape measuring device and the grinding target part is ground by the grinding tool.

Description

Technical Field

[0001] This disclosure relates to grinding systems, grinding methods, and methods for manufacturing steel products. In particular, this disclosure relates to grinding systems, grinding methods, and methods for manufacturing steel products for removing defects present on the surface of products such as steel pipes, bars, and round bars. Background Technology

[0002] In the manufacturing of steel pipes or bars, defects (flaws) sometimes occur on the outer surface of the product. These defects occur at random locations on the outer surface of the product, and the shapes of the products vary greatly. Therefore, in the past, defects were mostly removed manually by grinding with a grinding machine.

[0003] As a method for automatically removing defects, for example, Patent Document 1 discloses a defect grinding system that detects the location of defects in an object, generates a trajectory for a grinding tool to grind the defects, and grinds the defects by moving the grinding tool along the trajectory.

[0004] Patent Document 1: Japanese Patent No. 7248148

[0005] According to Patent Document 1, it is possible to grind away defects (flaws) existing in various locations. For example, when the object is a cylindrical or long product such as a steel pipe, bar, or round bar, linear defects sometimes exist over a wide area. Furthermore, defects sometimes exist beyond the movable range of the grinding device (e.g., approximately 180° in front of the grinding device). For such defects, a method is sought that can efficiently grind without manual intervention. Here, efficient grinding refers to grinding a defect with fewer measurement or grinding passes than in the prior art. Summary of the Invention

[0006] The purpose of this disclosure, made in view of this situation, is to provide a grinding system, grinding method, and method for manufacturing steel products that can perform efficient grinding.

[0007] (1) One embodiment of the grinding system disclosed herein includes:

[0008] Shape measuring device, used to measure the three-dimensional shape and orientation of the workpiece;

[0009] The detection device detects the position and shape of the grinding target portion present on the surface of the workpiece being machined;

[0010] Grinding apparatus, equipped with grinding tools for grinding the aforementioned grinding object;

[0011] The moving mechanism causes the workpiece to move relative to the shape measuring device and the grinding device.

[0012] A grinding tool control device generates a trajectory for grinding the workpiece based on the three-dimensional shape and orientation of the workpiece measured by the shape measuring device and the position and shape of the grinding target portion detected by the detection device, and controls the grinding device to move the grinding tool along the trajectory; and

[0013] The moving mechanism control device controls the moving mechanism in such a way that the workpiece moves relative to the shape measuring device and the grinding device when the shape measuring device measures the workpiece and when the grinding tool grinds the grinding target.

[0014] (2) As one embodiment of this disclosure, based on (1),

[0015] The workpiece described above is a circular part with a circular cross-section along the axial direction.

[0016] (3) As one embodiment of this disclosure, based on (1) or (2),

[0017] The aforementioned mobile mechanism has:

[0018] A rotating mechanism that moves the circumferential position of the workpiece relative to the shape measuring device and the grinding device; and

[0019] The sliding mechanism causes the axial position of the workpiece to move relative to the shape measuring device and the grinding device.

[0020] (4) As one embodiment of this disclosure, based on any one of (1) to (3),

[0021] The aforementioned moving mechanism control device moves the circumferential and axial positions of the workpiece relative to each other based on the position and shape of the grinding object.

[0022] (5) As one embodiment of this disclosure, based on any one of (1) to (4),

[0023] When the size of the object being ground is larger than the movable range of the grinding tool.

[0024] The aforementioned grinding tool control device generates a trajectory within the aforementioned movable range and controls the grinding device by moving the grinding tool along the trajectory.

[0025] The aforementioned moving mechanism control device determines the relative movement of the circumferential and axial positions of the workpiece based on the size of the grinding object and the movable range of the grinding tool.

[0026] (6) As one embodiment of this disclosure, based on any one of (1) to (5),

[0027] The aforementioned moving mechanism control device prioritizes the larger grinding object portion and excludes other grinding objects that overlap with the larger grinding object portion to determine the relative movement of the workpiece's circumferential and axial positions.

[0028] (7) One embodiment of the grinding method disclosed herein includes:

[0029] The shape measurement process uses a shape measurement device to measure the three-dimensional shape and orientation of the workpiece.

[0030] The inspection process includes inspecting the position and shape of the grinding target portion present on the surface of the workpiece; and

[0031] In the grinding process, based on the measured three-dimensional shape and posture of the workpiece and the detected position and shape of the grinding target area, a trajectory for the movement of the grinding tool of the grinding apparatus is generated, and the grinding tool is moved along the trajectory to grind the grinding target area.

[0032] In the above-mentioned shape measurement process and grinding process, the workpiece to be machined is moved relative to the shape measurement device and the grinding device.

[0033] (8) In one embodiment of the present disclosure, the steel product manufacturing method grinds the grinding target part of the surface of the steel product, which is the workpiece, by the grinding method of (7).

[0034] According to this disclosure, a grinding system, grinding method, and method for manufacturing steel products that can perform efficient grinding can be provided. Attached Figure Description

[0035] Figure 1 This is a diagram showing an outline of a grinding system according to one embodiment of the present disclosure.

[0036] Figure 2 This is a diagram illustrating an example of a defect in this disclosure.

[0037] Figure 3A It is a diagram showing the position of the markings and the rotation position of the grinding wheel.

[0038] Figure 3B It is a diagram showing the process flow of the grinding method.

[0039] Figure 4A It is a diagram used to illustrate the calculation of the trolley position.

[0040] Figure 4B It is a diagram used to illustrate the calculation of the trolley position.

[0041] Figure 4C It is a diagram used to illustrate the calculation of the trolley position.

[0042] Figure 5 This is a diagram illustrating the circumferential marker detection process.

[0043] Figure 6 It is a diagram that shows a summary of the circumferential unfolding.

[0044] Figure 7A This diagram illustrates the method for determining the shear range of a circumferential unfolded diagram.

[0045] Figure 7B It is a diagram representing the geometric model used for angle calculation of the workpiece.

[0046] Figure 8A It is a graph representing the shear range on a two-dimensional image.

[0047] Figure 8B It is a diagram representing the circumferential unfolded diagram that has been created.

[0048] Figure 9A This is a graph representing the detection of markers.

[0049] Figure 9B This is another diagram representing the detection of the marker.

[0050] Figure 9C This is another diagram representing the detection of the marker.

[0051] Figure 9D This is another diagram representing the detection of the marker.

[0052] Figure 9E This is another diagram representing the detection of the marker.

[0053] Figure 9F This is another diagram representing the detection of the marker.

[0054] Figure 9G This is another diagram representing the detection of the marker.

[0055] Figure 9H This is another diagram representing the detection of the marker.

[0056] Figure 9I This is another diagram representing the detection of the marker.

[0057] Figure 10 This is a diagram showing the process of rotation towards the grinding rotation position i.

[0058] Figure 11 It is a diagram showing the process from 3D imaging to trajectory generation.

[0059] Figure 12 This is a diagram showing the process of the grinding action at the grinding rotation position i.

[0060] Figure 13 This is a graph illustrating the effect of a decrease in the number of practitioners. Detailed Implementation

[0061] Hereinafter, a grinding system, grinding method, and method for manufacturing steel products according to one embodiment of the present disclosure will be described with reference to the accompanying drawings. In the drawings, the same or equivalent parts are labeled with the same reference numerals. In the description of this embodiment, descriptions of the same or equivalent parts are appropriately omitted or simplified.

[0062] Traditionally, for example, when dealing with defects that occur over a wide area of ​​a workpiece that is circular, a human operator would perform grinding operations while moving or rotating the workpiece. In systems that automate defect removal, the operation is also analyzed by dividing the work into the following elements. If we analyze the grinding operation performed by the operator, the grinding operation includes (element 1) determining the location of defects along the length of the workpiece, (element 2) determining the location of defects along the circumference of the workpiece, and (element 3) removing the defects by pressing the grinding tool against the defect location. Hereinafter, the system will be explained by appropriately dividing the operation into these elements.

[0063] (System overall structure)

[0064] Figure 1 This section outlines the grinding system according to this embodiment. The grinding system is a system for removing defects present on the surface of the workpiece 1, and includes a shape measuring device, a detection device, a grinding apparatus, a moving mechanism, a grinding tool control device, and a moving mechanism control device 12. The detection device, the grinding tool control device, and the moving mechanism control device 12 can, for example, be composed of one computer or multiple computers connected via a network.

[0065] In this embodiment, the workpiece 1 is, for example, a circular part with a circular cross-section along the axial direction, specifically a cylindrical or elongated component such as a steel pipe. The surface of the workpiece 1 contains defects or other grinding-related parts 2 that should be ground.

[0066] In this embodiment, the three-dimensional shape measuring device 3 (an example of a shape measuring device) measures the three-dimensional shape and orientation of the workpiece 1. The three-dimensional shape measuring device 3 is generally referred to as a 3D camera and is a measuring device capable of simultaneously obtaining two-dimensional image information and three-dimensional point group (stereo) information.

[0067] In this embodiment, the image processing device 4 (an example of a detection device) detects the position and shape of the grinding object portion 2 present on the surface of the workpiece 1. The image processing device 4 detects the position and shape of the grinding object portion 2 by performing image processing on images captured by the three-dimensional shape measuring device 3. The image processing can utilize known methods, for example, that employ machine learning models such as deep learning.

[0068] Here, the grinding apparatus is a device equipped with a grinding tool for grinding the grinding target 2. Furthermore, the grinding tool control device is a device that controls the grinding apparatus. The grinding tool control device generates a trajectory for the grinding tool used to grind the grinding target 2 based on the three-dimensional shape and posture of the workpiece 1 and the position and shape of the grinding target 2, and controls the grinding tool to move along this trajectory. In this embodiment, the robot motion control device 5 (an example of a grinding tool control device) performs inverse kinematics calculations based on the position of the grinding target 2 detected by the image processing device 4. In this embodiment, a motion trajectory is generated for a multi-joint robot 6 (an example of a grinding apparatus) that presses the grinding wheel 8 (an example of a grinding tool) equipped on the grinding machine 7 against the position of the grinding target 2. The multi-joint robot 6 moves according to the generated motion trajectory, and the grinding wheel 8 contacts the workpiece 1 to grind the grinding target 2. At this time, the grinding reaction force measuring device 9 can measure the reaction force generated in the grinding machine 7. The robot arm motion control device 5 can control the movement of the multi-joint robot arm 6 by pressing or avoiding (moving away) the grinding wheel 8, so that the measured reaction force becomes the reaction force targeted in grinding.

[0069] The grinding system according to this embodiment includes a moving mechanism that moves the workpiece 1 relative to the three-dimensional shape measuring device 3 and the multi-joint robot 6. The moving mechanism may include: a rotation mechanism that rotates the workpiece 1 relative to the three-dimensional shape measuring device 3 and the multi-joint robot 6; and a sliding mechanism that moves the workpiece 1 relative to the three-dimensional shape measuring device 3 and the multi-joint robot 6 in a direction different from the rotation direction. In this embodiment, the grinding system has a moving carriage 10 (an example of a sliding mechanism) that moves the multi-joint robot 6 relative to the workpiece 1 in the axial direction of the workpiece 1 as the moving mechanism. Alternatively, in this embodiment, the grinding system has a rotating roller 11 (an example of a rotation mechanism) that rotates the workpiece 1 relative to the three-dimensional shape measuring device 3 and the multi-joint robot 6 in the circumferential direction of the workpiece 1 as the moving mechanism. Here, the three-dimensional shape measuring device 3 can also be moved in the axial direction of the workpiece 1 via a sliding mechanism (not shown). In this embodiment, the three-dimensional shape measuring device 3 moves axially along the workpiece 1 in conjunction with the moving trolley 10 (i.e., in conjunction with the multi-joint robot 6). Thus, the measuring range of the three-dimensional shape measuring device 3 is linked to the movable range of the multi-joint robot 6.

[0070] exist Figure 1 In this example, the multi-joint robot 6 is mounted on a moving trolley 10 capable of moving axially along the workpiece 1. The workpiece 1 is also configured to rotate about an axis on a rotating roller 11. The moving trolley 10 and the rotating roller 11 are controlled by a movement mechanism control device 12. The movement mechanism control device 12 can freely adjust the position of the multi-joint robot 6 axially (in the length direction) relative to the workpiece 1 via the moving trolley 10. Furthermore, the movement mechanism control device 12 rotates the workpiece 1 via the rotating roller 11, thereby freely adjusting the angle (rotation angle) of the workpiece 1 about the axis relative to the three-dimensional shape measuring device 3 and the multi-joint robot 6. When the three-dimensional shape measuring device 3 measures the workpiece 1 and when the grinding wheel 8 grinds the grinding target portion 2, the movement mechanism control device 12 controls the movement mechanism in a manner that the workpiece 1 moves relative to the three-dimensional shape measuring device 3 and the multi-joint robot 6. The movement mechanism control device 12 can move the circumferential and axial positions of the workpiece 1 relative to the grinding target portion 2 based on its position and shape. Details will be described later, but when the size of the grinding object 2 is greater than the movable range of the grinding wheel 8, the moving mechanism control device 12 can determine the relative movement of the circumferential and axial positions of the workpiece 1 based on the size of the grinding object 2 and the movable range of the grinding wheel 8.

[0071] Figure 2 This is a diagram illustrating an example of a defect in this disclosure. The grinding object 2 can be a defect itself present on the surface of the workpiece 1 (see Figure 1). Figure 2 The marking (as shown in the diagram above) can also be applied in a manner that includes defects, as in this embodiment. The type, shape, and size of the grinding target part 2 are not limited to a specific object. In this embodiment, defects detected in non-destructive inspection (NDI) performed on a different production line than grinding are marked, and then the workpiece 1 is transported to the grinding production line. Furthermore, in this embodiment, the marking on the workpiece 1 is used as the "grinding target part 2" for grinding.

[0072] (Grinding method)

[0073] Figure 3A An image showing the position of the marks and the grinding rotation position for grinding based on the rotating roller 11. According to the logic described later, the grinding rotation angle θpi (i = 0~N, where N is the number of grinding rotation positions, i.e., the number of marks) corresponding to each mark in the circumferential direction is calculated respectively. By rotating the rotating roller 11 from the initial position (i = 0) by θpi, the marks are set to exist in the optimal position (i.e., within the range of motion of the multi-joint manipulator 6, which is the grinding device, and within the measurement range of the three-dimensional shape measuring device 3).

[0074] Here, the grinding system in the steel product manufacturing method can perform a grinding method to grind the grinding target portion 2 on the surface of the steel product, which is the workpiece 1. The grinding method performed by the grinding system includes a shape measurement step, an inspection step, and a grinding step. In the shape measurement step and the grinding step, the workpiece 1 is moved relative to the shape measurement device and the grinding device. Here, the shape measurement step is a step of measuring the three-dimensional shape and orientation of the workpiece 1 using the shape measurement device. The inspection step is a step of detecting the position and shape of the grinding target portion 2 existing on the surface of the workpiece 1. In addition, the grinding step is a step of generating a trajectory for the movement of the grinding tool of the grinding device based on the measured three-dimensional shape and orientation of the workpiece 1 and the detected position and shape of the grinding target portion 2, and moving the grinding tool along the trajectory to grind the grinding target portion 2.

[0075] Figure 3B Here is an example of the specific processing flow of this grinding method. First, the position of the mark along the axial direction of the workpiece 1 is obtained. The position of the mark can be obtained, for example, by measuring the surface of the workpiece 1 using a three-dimensional shape measuring device 3, or by using an external sensor different from the three-dimensional shape measuring device 3. Referring to the obtained mark position along the length direction of the workpiece 1, the number of carriage positions (the number of positions the moving carriage 10 moves) M and the carriage position Lpk (k = 0 ~ M) are calculated (step S1). The carriage position Lp0 (k = 0) is the initial position.

[0076] The moving trolley 10 moves to the calculated positions (step S2). That is, the grinding system moves the three-dimensional shape measuring device 3 and the multi-joint robot 6. Then, at the position, the three-dimensional shape measuring device 3 performs circumferential mark detection on the workpiece 1 (step S3), and calculates the required number of grinding rotation positions N and the grinding rotation angle θpi of each mark.

[0077] The rotating roller 11 is rotated based on the calculated angle information, so that the workpiece 1 is at the appropriate grinding rotation position i (step S4). The three-dimensional shape measuring device 3 is used to measure the three-dimensional shape of the workpiece 1, and a machining trajectory is generated based on its shape for grinding (step S5). The grinding process is repeated N times at the grinding rotation position (step S6, no). If grinding has been performed at all grinding rotation positions i (step S6, yes), the machine moves to the next carriage position (carriage position). The machine moves to the carriage position M times (step S7, no), and steps S2 to S6 are repeated. If grinding has been performed at all carriage positions k (step S7, yes), the grinding of one workpiece 1 is completed.

[0078] As described above, in this embodiment, the workpiece 1 is moved relative to the three-dimensional shape measuring device 3 and the multi-joint robot 6 during the shape measurement and grinding processes. Therefore, even if defects exist outside the measurement range of the three-dimensional shape measuring device 3 and outside the movable range of the multi-joint robot 6, defects can be detected and ground by moving the workpiece 1 relative to it, enabling efficient grinding.

[0079] (Calculation of the position of the moving trolley 10)

[0080] Figure 4A This is a diagram used to illustrate the calculation of the trolley position, showing the image of the mark position and the shooting range. The distance from the origin of the length to the starting position of the mark is Lsk (k = 0~M), and the size of the mark is Lk. Marks that coincide in the length direction (axial direction of the workpiece 1) are set as one mark. Table 1 is a list of individual marks and combinations of multiple marks. For marks larger than the shooting range of the three-dimensional shape measuring device 3, i.e., Lm, the long mark is set to "1", and all others are set to "0". In addition, the ending position Lek of mark k is calculated using formula (1).

[0081] Lek = Lk + Lsk … Equation (1)

[0082]

[0083] Furthermore, the representation and position of multiple tags (combinations of multiple tags) use the format and calculation formula shown in Table 2. For example, multiple tags with tag No. "1-2" refer to a combination of tags "1" and "2". The following explanation uses this tag list as an example to illustrate the tag position processing flow. The tag position processing flow is similar to... Figure 3B The detailed process corresponding to step S1.

[0084]

[0085] (Step 1)

[0086] As shown in Table 3, a column "Single Grinding Range Rank" has been added to sort the markers marked with "0" in descending order of length.

[0087]

[0088] (Step 2)

[0089] As shown in Table 4, the trolley position Lp1 is calculated for the marker whose first position is "single grinding range position". When the first position is marker k, the trolley position Lp1 is calculated using equation (2).

[0090] Lp1=Lsk+Lk / 2… Formula (2)

[0091]

[0092] (Step 3)

[0093] As shown in Table 5, the process involves deleting combinations or individual markers that include the marker whose "single grinding range position" is the first position. That is, the process involves deleting markers that are duplicates of markers with larger dimensions.

[0094]

[0095] (Step 4)

[0096] As shown in Table 6, Equation (2) is used to calculate the trolley position Lp2 of the second largest mark in the "single grinding range position". In Equation (2), Lp1 is replaced by Lp2.

[0097]

[0098] (Step 5)

[0099] Before any markers other than the long marker are found (taking all markers with a long marker of "0" as the target), repeat steps (2) to (4) above. When there are no long markers, the position calculation of the moving trolley 10 ends.

[0100] (Step 6)

[0101] Here, as Figure 4B As shown, Lpk and Lpn, which serve as the positions of the trolley, are adjusted so that the center of a single mark or multiple marks is aligned with the center of the shooting range.

[0102] (Step 7)

[0103] As shown in Table 7, calculations are performed for the remaining long tags. Additionally, as... Figure 4C As shown, ΔLp can be set as the overlap between the shooting range and the grinding range of the long mark. At this time, the grinding number Sk, the total grinding range Lpak, the grinding start position Lpask, and each grinding position Lpkn (n=1~Sk) of the long mark are calculated using equations (3) to (6). Here, Sk in equation (3) is assigned an integer by rounding up.

[0104] Sk=(Li+ΔLp) / Lm… Formula (3)

[0105] Lpak=Lm+(Sk-1)(Lm-ΔLp)…Equation (4)

[0106] Lpask=(Lpak-Li) / 2… Formula (5)

[0107] Lpkn=Lsi-Lpask+n(Lm-ΔLp) / 2… Formula (6)

[0108]

[0109] (Step 8)

[0110] In Table 8, calculate the trolley position Lpk for all single or multiple markers.

[0111]

[0112] (Step 9)

[0113] Table 9 is organized into lists of only trolley position Lp, multiple markers, and long markers, and then sorted in ascending order by Lpk.

[0114]

[0115] (Step 10)

[0116] As shown in Table 10, when there are multiple long tags, the tag number can be aligned according to each long tag.

[0117]

[0118] Here, by performing the process in step 3, the moving mechanism control device 12 can prioritize the larger grinding target portion 2 (marker) and exclude other grinding target portions 2 that overlap with the larger grinding target portion 2 to determine the relative movement amount of the axial position of the workpiece 1. Furthermore, the same process is performed for the circumferential position. Therefore, the grinding system according to this embodiment can perform grinding efficiently.

[0119] (Detection method for circumferential markers)

[0120] Figure 5 This indicates the circumferential marker detection process, i.e. Figure 3B The detailed process of step S3 is as follows: First, the creation range of the "circumferential unfolded diagram" is specified. Next, the rotation time ttr of the rotary roller 11 is calculated, and a rotary roller rotation start command is output. At the same time, a continuous shooting command is sent to the three-dimensional shape measuring device 3 to perform circumferential unfolded diagram creation processing until the timer has elapsed for the rotation time ttr. After ttr, a rotary roller rotation stop command is issued, the marker is detected from the created circumferential unfolded diagram, and the position is calculated to determine the number of grinding rotation positions N and the grinding rotation angle θpi. Then, based on the determined angle information, the rotary roller 11 is rotated so that the workpiece 1 is at the appropriate grinding rotation position i.

[0121] Figure 6This is a diagram showing a summary of the circumferential development. The workpiece 1 is continuously rotated while being captured in two dimensions by a three-dimensional shape measuring device 3 at regular intervals. For example... Figure 6 As shown, images are cut from specific portions of the workpiece 1 captured in the photographed images and arranged in the order of the photographs to create a circumferential unfolded diagram. The circumferential unfolded diagram is a graph where the length of the workpiece 1 is marked on the horizontal axis and the angular positions are marked on the vertical axis. The positions of the markers are calculated based on the circumferential unfolded diagram. Figure 6 The excess part is the repeating part obtained by rotating more than 360°.

[0122] Figure 7A This is a diagram used to illustrate the method for determining the shearing range of the circumferential unfolded diagram, showing the relationship between the image of the captured two-dimensional image and the parameters that determine which position on the shearing image. The workpiece position (upper) pU and workpiece position (lower) pL on the image that serves as the reference for the shearing position are calculated using equations (7) and (8).

[0123] pU=a1×Dp+b1 … Equation (7)

[0124] pL=a2×Dp+b2 … Equation (8)

[0125] Here, Dp is the diameter of the workpiece being cut. The diameter Dpp of the workpiece on a pixel is calculated according to equation (9).

[0126] Dpp=pU-pL … Equation (9)

[0127] The shear position (upper) ys and shear position (lower) ye on the image are calculated using equations (10) and (11).

[0128] ys=pU+Dpp×cU … Equation (10)

[0129] ye=pU+Dpp×cE… Formula (11)

[0130] Here, a1, b1, a2, and b2 are arbitrary coefficients. For example, they are determined by taking pictures in multiple patterns with varying diameters of the workpiece 1, marking the vertical position of each image, and using the least squares method as a function of Dp. cU and cE are scaling parameters between 0 and 1, determining the height position of the workpiece 1 in the cut image. They are set to satisfy the relationship cE > cU. Figure 7BThis represents the geometric model used for angle calculation of workpiece 1. The angles and arc lengths of the regions reflected on the surface of workpiece 1 are calculated based on pU, pL, ys, and ye. The upper position of the image of workpiece 1 reflected by the image captured by the three-dimensional shape measuring device 3 is set to 0°. The angle θa to the shearing position (upper) ys and the angle θb to the shearing position (lower) ye are calculated using equations (12) and (13).

[0131] θa=cos -1 {(50-cU) / 50}… Formula (12)

[0132] θb=cos -1 {(50-cU-cE) / 50}… Formula (13)

[0133] In addition, using the angle obtained by the above formula, the shearing angle range θr and shearing arc length ΔR are calculated according to formulas (14) and (15).

[0134] θr=a4×θb-a3×θa … Equation (14)

[0135] ΔR=Dp / 2×θs…Equation (15)

[0136] Here, a3 and a4 are preferably arbitrarily set parameters, preferably within the range of 0 to 2. a3 and a4 are parameters that compensate for the error between the actual model and the geometric model, and are appropriately changed according to the values ​​of cU, cE, etc.

[0137] Figure 8A The clipping range on the two-dimensional image is represented. As shown in the figure, when the vertical axis of the image is set as the y-axis and the horizontal axis as the x-axis, the clipping range is defined by a rectangle with the two points (xs, ys) and (xe, ye) as the diagonal vertices. ys and ye are obtained by equations (10) and (11). xs and xe are set based on the range that the three-dimensional shape measuring device 3 can capture and the possible range of motion of the multi-joint manipulator 6. Here, when the x-direction positions of xs and xe in the three-dimensional space are set as xs3 and xe3, the above-mentioned capture range Lm is set according to equation (16) in order to achieve matching.

[0138] Lm=xe3-xs3 … Equation (16)

[0139] In addition, when the rotational speed of the workpiece 1 is set to V, the shooting interval tc and the rotation time ttr during shooting are calculated by equations (17) and (18).

[0140] tc=ΔR / V(s)…Equation (17)

[0141] ttr=tc(360+α) / θr… Formula (18)

[0142] α is the margin for creating the circumferential unfolded diagram, preferably set to a value of 360° or more.

[0143] Figure 8B This represents the created circumferential unfolded diagram. The workpiece 1 is rotated at a circumferential speed V and photographed at an interval tc for a rotation time ttr. The images that cut the range defined by (xs, ys) and (xe, ye) above are arranged in the order of photographing to create the circumferential unfolded diagram.

[0144] Figures 9A to 9I This is a graph representing the detection of markers in various patterns. First, Figure 9A The marking positions in the circumferential development diagram are illustrated. In this embodiment, the circumferential development diagram has a length position L on the horizontal axis and an angle position on the vertical axis, with the upper left corner referred to as point 0. The angle position of the starting position of the i-th mark (denoted as mark i) from point 0 is set as θsi, and the range of angles is set as θi. Additionally, the length position of the starting position of the mark from point 0 is set as Lsi, and the range of lengths is set as Li. Table 11 is a list of marks present in the circumferential development diagram. At this time, marks with θsi ≥ 360° ( Figure 9A The 2) mark is excluded from the list as a duplicate mark.

[0145]

[0146] Figure 9B This is an example of a circumferential unfolded diagram showing a small-sized mark existing as a single unit. Here, θm in the diagram is the smaller of the angle range that can be captured at one time by the three-dimensional shape measuring device 3 or the movable range of the multi-joint manipulator 6. Here, it is assumed that the mark with an angle range θ > θm is a large mark, and the large mark flag is set to "1". For marks that are not large marks, the large mark flag is set to "0". Here, the mark end positions θei and Lei are calculated using equations (19) and (20). In addition, the grinding rotation angle θpi at the grinding rotation position i is calculated using equation (21).

[0147] θei=θsi+θi… Formula (19)

[0148] Lei=Lsi+Li… Formula (20)

[0149] θpi=θsi+θi / 2… Formula (21)

[0150] Table 12 shows a list of markers. This list includes the angular position, length position (axial position), and marker mark obtained by equations (19) to (21) for each marker, which are created at each trolley position of the moving trolley 10. In the example of Table 12, there is one row because it is a single marker, but in the case of multiple markers described later, it becomes a multi-row list.

[0151]

[0152] Figure 9C This section shows an example of multiple small-sized markers. Table 13 lists these markers. Additionally, Table 14 defines the angles and positions of the multiple markers (the method for determining their values). Table 15 shows a revised list of the multiple markers. Follow the steps below to revise the markers in the list.

[0153]

[0154]

[0155]

[0156] A flag is set for a position where grinding can be performed without rotating the workpiece 1 (grinding capability flag at a position). If the larger flag is "1", i.e., θi > θm, then the grinding capability flag at a position becomes "0". Conversely, if θi ≤ θm, then the grinding capability flag at a position becomes "1".

[0157] Next, for each location marked as "1" for grinding capability, the existing range angles are sorted. The marker with the largest existing range angle (largest size) is set as the first position.

[0158] Similar to step 3 of the trolley position calculation above, the process of deleting marks that are duplicates of marks with larger dimensions is performed. For other marks, the process of selecting the mark with the largest range angle and deleting duplicate marks is repeated until all grinding availability flags at a certain position become "1". Here, the grinding order is set to the order of grinding angle (rotation angle) θp from smallest to largest.

[0159] Figure 9D This illustrates an example where small marks exist between multiple small-sized marks. Table 16 shows the list of marks. In this example, a small mark (4) exists between multiple valid marks (2-3). When the angle of the presence of a small mark is included within the angle of the presence of a large-sized mark, the small mark can be ignored (deleted) since it can be ground together. This allows for more efficient grinding.

[0160]

[0161] Figure 9E Examples of large-size markings are shown. In markings where the large marking is marked "1", the number of grinding cycles Si, the total grinding range θpai, the grinding start position θpasi, and the grinding rotation angles θpin (n = 1 ~ Si) of the large marking are calculated using equations (22) to (25). Here, Δθp is set as the overlap of the grinding range of the large marking. In addition, Si in equation (22) is assigned an integer by rounding up.

[0162] Si=(θi+Δθp) / θm… Equation (22)

[0163] θpai=θm+(Si-1)(θm-Δθp)…Equation (23)

[0164] θpasi=(θpai-θi) / 2… Formula (24)

[0165] θpin=θsi-θpasi+n(θm-Δθp) / 2…Equation (25)

[0166] Large marks are ground independently of other marks. As shown in Table 17, a large mark has multiple grinding rotation angles θpin (n = 1 ~ Si) relative to a mark.

[0167]

[0168] Figure 9F The circumferential unfolding diagram shows the pattern of large and small markings. Table 18 shows the list of markings. Regardless of the presence of other markings, the large markings use the grinding angles obtained by equations (22) to (25).

[0169]

[0170] Figure 9G The circumferential unfolding diagram shows the pattern of markers where θsi is 0. Markers like "θsi = 0" are duplicates and are therefore ignored. Table 19 shows the list of markers in this case.

[0171]

[0172] Figure 9H A circumferential unfolded diagram showing the pattern of the slanted markings. Table 20 shows the list of markings.

[0173]

[0174] The following explains the calculation of the grinding range used to set the tilt mark. First, the outline length Lci of mark i, which is determined to be a large mark, is calculated.

[0175] The tilt mark flag is set to "1" if the following equation (26) is satisfied.

[0176] (Li+θi) / (Lci / 2)>ac… Formula (26)

[0177] Here, ac is the threshold for determining the tilt mark, which is an arbitrarily set parameter. Furthermore, the smallest bounding rectangle of the tilt mark is calculated, and the positions of the four corners of the rectangle are calculated as (Lr1, θr1), (Lr2, θr2), (Lr3, θr3), and (Lr4, θr4).

[0178] Additionally, a straight line fitting is performed on the circumscribed rectangle. The reference point of the circumscribed rectangle is determined based on the coefficient 'a' of the function "θ = aL + b" used to fit the straight line. Figure 9H In the example, a is a value less than 0. Regarding the longer side of one (upper) side of the circumscribed rectangle, b1 is calculated by equation (27) when solving θ = aL + b1.

[0179] b1=θr2 / aLr2 … Equation (27)

[0180] Calculations are performed for the reference rectangle assumed to be the grinding range. The coordinates (Lr5, θr5) of reference point 1 are calculated using equations (28) and (29), respectively.

[0181] Lr5=(θr5-b1) / a … Equation (28)

[0182] θr5=θpai+θm / 2…Equation (29)

[0183] In addition, the coordinates (Lr6, θr6) of reference point 2 are calculated using equations (30) and (31), respectively.

[0184] Lr6 = Lr1 … Equation (30)

[0185] θr6=θr2 … Equation (31)

[0186] The angle range θref and length range Lref of the rectangle are calculated using equations (32) and (33), respectively.

[0187] θref=θsi-θpasi+θm-θr2... Equation (32)

[0188] Lref=Lr5-Lsi … Equation (33)

[0189] In addition, such as Figure 9I Then set another reference rectangle. The coordinates (Lr7, θr7) of reference point 3 are calculated using equations (34) and (35), respectively.

[0190] Lr7 = Lr3 … Equation (34)

[0191] θr6=θr4 … Equation (35)

[0192] The full grinding angle range θalli and the full grinding length range Lalli are calculated using equations (36) and (37), respectively.

[0193] θalli=θr4-θr2… Formula (36)

[0194] Lalli=Lr3-Lr1… Formula (37)

[0195] The number of grinding passes, Si, is calculated using equation (38). The Si in equation (38) is given as an integer by rounding up.

[0196] Si=θall / θref… Formula (38)

[0197] The circumferential movement θti and the axial movement Lti are calculated using equations (39) and (40), respectively.

[0198] θti=(θalli-θref) / (Si-1)…Equation (39)

[0199] Lti=(Lalli-Lref) / (Si-1)… Formula (40)

[0200] The angular grinding overlap Δθri and the positional grinding overlap ΔLri are calculated using equations (41) and (42), respectively.

[0201] Δθri=θsi-θr2…Equation (41)

[0202] ΔLri=Lsi-Lr1 … Equation (42)

[0203] The grinding rotation angle θpin is calculated using equation (43). Here, j is an integer in the range of 1 to Si.

[0204] θpin=θpai1+(j-1)×θti … Equation (43)

[0205] In the above calculations, well-known and readily available image processing functions can be used. For example... Figure 9I As shown, the grinding rotation angle θpin, angular grinding overlap Δθri, positional grinding overlap ΔLri, and axial movement Lti are calculated in a manner that allows for the overlap of reference rectangles such as those covering the tilted markers. Table 21 is a list of markers that include these calculated values.

[0206]

[0207] Table 22 is an example of the final marker list. Grinding is performed according to this marker list in the order of "tilted marker," "large marker," "single marker," and "multiple markers." Within the same category, grinding is performed in ascending order of grinding rotation angle θpi. The number of rows in the marker list corresponds to the number of grinding rotation positions N. Additionally, this list can be used for masking for grinding trajectory generation, and for carriage position movement (additional processing) of large and tilted markers.

[0208]

[0209] (Methods for generating trajectories)

[0210] Figure 10 The process of rotation at grinding rotation position i is described, and... Figure 3B The detailed process of step S4 corresponds to the following. In order to rotate the workpiece 1 to the grinding rotation angle θpi at the grinding rotation position i, the rotating roller 11 rotates. At this time, the rotation angle θti of the rotating roller and the rotation time ttri are obtained by equation (44) and equation (45).

[0211] θti=Dp / Dt×(θpi-θp(i-1))… Equation (44)

[0212] ttri=θti / V … Equation (45)

[0213] Here, Dt is the diameter of the rotating roller. By issuing a command to the rotating roller 11 to rotate it for a rotation time ttri, the workpiece 1 can be rotated to the desired angle.

[0214] Figure 11 This represents the process from 3D imaging to trajectory generation at grinding rotation position i, and... Figure 3BThe detailed process corresponding to step S5, up to the grinding pre-pressurization stage, is as follows: First, a measurement is performed using the three-dimensional shape measuring device 3. The measured data is in the form of a two-dimensional image associated with three-dimensional point group (stereo) information. First, the range of the mark at the grinding rotation position i is cut off from the two-dimensional image of the measured data. This is to prevent trajectory generation from mixing with other marks. Next, a known color extraction filter (e.g., an HSV color extraction filter) is used to extract only the marks from the two-dimensional image. By applying a filter that sets the range to "1" and the outside range to "0", only the desired color can be extracted into a binary image. By further applying a mid-range filter, Gaussian filter, contour area threshold filter, or zoom filter to the extracted binary image, a noise-free, mark-only binary image can be obtained. By cutting off only the portion where the mark exists, mark-only three-dimensional point group data can be obtained. Through this series of processes, mark-only two-dimensional and three-dimensional data can be obtained. Trajectory generation is performed based on this three-dimensional data.

[0215] Here, a mask can also be set. For example, although the positions pU and pL of the workpiece 1 on the image are obtained by the above formula, the mask can be set in such a way that only the area where the interval is further reduced upward and downward from that position is cut. For example, the mask can be set downward from the upper position pU of the workpiece 1 on the image to the position ymU. Alternatively, the mask can be set upward from the lower position pL of the workpiece 1 on the image to ymL. The positions of ymU and ymL on the image can be calculated by formulas (46) and (47).

[0216] ymU=pU+Dpp×(cmU+Dpp×amU)…Equation (46)

[0217] ymL=pL-Dpp×(cmL+Dpp×amL) … Equation (47)

[0218] Here, cmU, cmL, amU, and amL are parameters that can be set arbitrarily. cmU and cmL are parameters that set the ratio of the mask range on the image to the diameter Dpp of the workpiece 1. In addition, amU and amL are parameters for performing diameter-based mask range correction, and are preferably set between 0 and 1.

[0219] Trajectory generation is performed by setting grinding parameters and configuring "machining control points (control points)" along the obtained 3D data marked only. Grinding parameters are a set of parameters used to set which part of the marked 3D point group to configure control points from, at what distance, the interval between control points, the interval of the "path" of one grinding cycle, and at what angle / distance to contact or disengage, etc. The set control points are sent as trajectory data to the multi-joint robot 6.

[0220] (Control methods for grinding tools)

[0221] Figure 12 This represents the flow of the grinding action executed at the grinding rotation position i, and... Figure 3B The detailed grinding process corresponds to step S5. If trajectory data is sent, the multi-joint robot 6 begins to move. After the multi-joint robot 6 completes one grinding cycle, additional processing is required in the case of large or tilted marks. In the case of other marks, grinding at the grinding rotation position i is completed.

[0222] Additional processing is performed during large-mark grinding. The rotation angle θti of the rotating roller 11 is determined by equation (48) based on the mark information list. Here, j in the equation is 1 < j < Si, indicating the j-th rotation position among the marks that become the grinding rotation position i.

[0223] θti=Dp / Dt×(θpij-θpi(j-1))… Equation (48)

[0224] After rotating the rotary roller 11 by an angle θti, the created trajectory data is sent to the multi-joint robot 6, which performs the grinding action. Then, by repeatedly rotating the rotary roller 11 and grinding until the set number of grinding times Si, the large mark can be ground using the initially created trajectory. That is, in the case of a large mark (where the size of the grinding object 2 is larger than the movable range of the grinding wheel 8), a trajectory within the movable range of the grinding wheel 8 (the measurement range of the three-dimensional shape measuring device 3) is generated at the position of angle θpi1 of the workpiece 1. Then, the multi-joint robot 6 is controlled to perform grinding in such a way that the grinding wheel 8 moves along the generated trajectory. Then, the workpiece 1 is rotated towards angle θpi2, and grinding is performed along the same trajectory created at the position of angle θpi1. Grinding and rotation are repeated in this way until the workpiece 1 is rotated to angle θpiSi.

[0225] In the case of trajectory generation, 3D imaging, color extraction processing, and trajectory generation calculation take time. Therefore, by using the trajectory data created once, large marks can be ground efficiently. Here, after grinding Si times, the rotation of the rotating roller 11 needs to be returned to the position where the original trajectory was generated. The rotation angle θre in this case is determined by equation (49).

[0226] θre=-Dp / Dtx(Si-1)θti… Formula (49)

[0227] Rotate the rotating roller 11 by θre, and the grinding at the rotating position i is completed.

[0228] Additionally, additional processing is performed during tilting mark grinding. Similar to large marks, the rotation angle θti of the rotating roller 11 based on the mark information list is calculated using equation (48).

[0229] After rotating the rotary roller 11 by an angle θti, the position of the moving trolley 10 is moved by Lti, and the created trajectory data is sent to the multi-joint robot 6, which then performs the grinding action. By repeatedly performing "rotation of the rotary roller 11, movement of the trolley, and grinding" until the set number of grinding times Si, the large mark can be ground using the initially created trajectory. After grinding Si times, the rotary roller 11 is rotated by θre, and the grinding at the rotation position i is completed. Similar to the large mark, the rotation angle θre is calculated using equation (49).

[0230] (The effect of a decrease in the number of practitioners)

[0231] Figure 13 This is a graph illustrating the effect of reducing the number of workers. When the number of workers in the grinding operation of the grinding machine 7 before implementing the method of this embodiment was set to 100, the number of workers after implementation became 13. The above-described grinding system, grinding method, and steel product manufacturing method, which provide efficient grinding, can reduce the number of workers performing grinding operations (labor saving) by automating the operation. Furthermore, further improvements in safety can be expected through operation automation.

[0232] While embodiments of this disclosure have been described with reference to the accompanying drawings and examples, it should be noted that those skilled in the art can readily make various modifications or alterations based on this disclosure. Therefore, it should be understood that such modifications or alterations are included within the scope of this disclosure. For example, the functions included in each component or step (process) can be reconfigured in a logically consistent manner, and multiple components or steps can be combined into one or divided. The embodiments involved in this disclosure can also be implemented as a program executed by a processor of a device or a storage medium containing a program. These should also be understood to be included within the scope of this disclosure.

[0233] Explanation of reference numerals in the attached figures

[0234] 1…Workpiece to be machined; 2…Grinding object; 3…Three-dimensional shape measuring device (an example of a shape measuring device); 4…Image processing device (an example of a detection device); 5…Robot motion control device (an example of a grinding tool control device); 6…Multi-joint robot (an example of a grinding device); 7…Grinding machine; 8…Grinding wheel (an example of a grinding tool); 9…Grinding reaction force measuring device; 10…Moving trolley (an example of a moving mechanism); 11…Rotating roller (an example of a moving mechanism); 12…Moving mechanism control device.

Claims

1. A grinding system, characterized in that, have: Shape measuring device, used to measure the three-dimensional shape and orientation of the workpiece; The detection device detects the position and shape of the grinding target portion existing on the surface of the workpiece; Grinding apparatus, comprising grinding tools for grinding the part to be ground; A moving mechanism that causes the workpiece to move relative to the shape measuring device and the grinding device; A grinding tool control device generates a trajectory for grinding the grinding object based on the three-dimensional shape and posture of the workpiece measured by the shape measuring device and the position and shape of the grinding object portion detected by the detection device, and controls the grinding device to move the grinding tool along the trajectory. as well as The moving mechanism control device controls the moving mechanism in such a way that the workpiece moves relative to the shape measuring device and the grinding device when the shape measuring device measures the workpiece and when the grinding tool grinds the grinding target.

2. The grinding system according to claim 1, characterized in that, The workpiece being machined is a circular workpiece with a circular cross-section along the axial direction.

3. The grinding system according to claim 1 or 2, characterized in that, The moving mechanism has: A rotating mechanism causes the workpiece to rotate circumferentially relative to the shape measuring device and the grinding device. and A sliding mechanism allows the workpiece to move axially relative to the shape measuring device and the grinding device.

4. The grinding system according to any one of claims 1 to 3, characterized in that, The moving mechanism control device moves the workpiece relative to each other in the circumferential and axial directions based on the position and shape of the workpiece being ground.

5. The grinding system according to any one of claims 1 to 4, characterized in that, When the size of the object being ground is larger than the movable range of the grinding tool. The grinding tool control device generates a trajectory within the movable range and controls the grinding device to move the grinding tool along that trajectory. The moving mechanism control device determines the relative movement of the workpiece in the circumferential and axial directions based on the size of the workpiece and the movable range of the grinding tool.

6. The grinding system according to any one of claims 1 to 5, characterized in that, The moving mechanism control device prioritizes the larger grinding object portion and excludes other grinding object portions that overlap with the larger grinding object portion to determine the relative movement of the circumferential and axial positions of the workpiece.

7. A grinding method, characterized in that, have: The shape measurement process uses a shape measurement device to measure the three-dimensional shape and orientation of the workpiece. The inspection process involves inspecting the position and shape of the grinding target portion present on the surface of the workpiece. as well as In the grinding process, based on the measured three-dimensional shape and posture of the workpiece and the detected position and shape of the grinding target area, a trajectory for the movement of the grinding tool of the grinding device is generated, and the grinding tool moves along this trajectory to grind the grinding target area. In the shape measurement process and the grinding process, the workpiece is moved relative to the shape measurement device and the grinding device.

8. A method for manufacturing steel products, characterized in that, The grinding object part is ground by the grinding method described in claim 7 to grind the surface of the steel product that is the workpiece.

Images