Convex portion grinding system, convex portion grinding method, and manufacturing method of steel products

Abstract

A projection polishing system comprises: a shape measurement device (3) that measures a three-dimensional shape and orientation of an object material; a projection detection device (4) that detects a projection that is present on a surface of the object material and recognizes the position and shape of the projection; a polishing device (7) provided with a polishing tool for polishing the projection; and a polishing tool control device (5) that calculates a trajectory for movement of the polishing tool on the basis of the measured three-dimensional shape and orientation of the object material, and the detected position and shape of the projection, and controls the polishing device so that the polishing tool moves along the trajectory while changing the angle of contact of the polishing tool with the projection.

Description

[Technical field]

[0001] The present disclosure relates to a convex portion grinding system, a convex portion grinding method, and a manufacturing method for a steel product. In particular, the present disclosure relates to a convex portion grinding system, a convex portion grinding method, and a manufacturing method for a steel product that remove harmful convex portions present on the surface of a steel product or the like. [Background technology]

[0002] Castings are provided with a "runner" through which the molten metal passes during casting, and a "feeder" that is used to keep the final cooling process outside the product to prevent harmful defects such as "porosity" that occur inside the product. Usually, the unnecessary parts are removed by cutting, shearing, hammering, or by breaking under its own weight in the process of removing the casting from the casting mold, but some of them remain and may become harmful "protrusions" on the surface of the casting.

[0003] In particular, in the case of many different types of products, the positions and shapes of the protrusions are diverse, so currently, the protrusions are often removed by grinding them manually using a grinder. Such protrusions can be as large as several tens of mm in height, which places a heavy burden on the grinding work and makes it difficult to secure workers. In addition, when the protrusions are large or made of difficult-to-process materials such as high alloy steel, it is difficult to perform grinding at high speeds.

[0004] Patent Document 1 proposes a method of grinding by attaching a grinder to a robot and applying a constant pressing force along a predetermined processing trajectory, while Patent Document 2 proposes a method of grinding steel materials at high speed by processing in a non-oxidizing gas atmosphere. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 3-178766 [Patent Document 2] Japanese Patent Application Publication No. 11-267954 Summary of the Invention [Problem to be solved by the invention]

[0006] Here, the technology of Patent Document 1 is a system that performs processing along a predefined trajectory, and cannot automatically handle a wide variety of products.

[0007] Furthermore, the technology of Patent Document 2 requires sealing and evacuating a large-scale line, resulting in extremely high equipment and running costs.

[0008] For the convex parts that appear on a wide variety of products, a human worker visually observes the workpiece, presses the grinder against the convex part of the workpiece with a pressure that he feels is appropriate, and stops pressing the grinder at an appropriate time. The worker visually determines whether the convex part remains and decides whether to regrind it or end the maintenance work. There was a demand for automation of such work.

[0009] The present disclosure has been made in consideration of the above circumstances, and aims to provide a convex portion grinding system, a convex portion grinding method, and a manufacturing method for steel products that automatically grind convex portions that occur in a wide variety of products. [Means for solving the problem]

[0010] The present inventors have thoroughly studied ways to solve the above problems. Analysis of the operator's work revealed that the work includes: (1) measuring the shape and posture of the workpiece based on visual information, (2) pressing the grinding wheel of the grinder, (3) sensing and controlling the grinding reaction force and load after pressing the grinding wheel based on touch and force senses, (4) changing the grinding wheel angle during grinding, and (5) inspecting the remaining condition of the protrusions after grinding based on visual information.

[0011] Based on the analysis of the above work, we propose a system as a method for automating grinding of convex parts of a workpiece that performs at least some of the following: (1) measuring the shape and posture of the workpiece using a three-dimensional shape measuring device, (2) recognizing the position of the convex parts, (3) measuring the grinding reaction force and load and controlling it, (4) controlling the pressing action against the convex part position which can change the contact angle of the grinding wheel during grinding, and (5) inspecting the remaining condition of the convex parts after grinding and deciding whether to re-grind.

[0012] [1] A convex portion grinding system according to an embodiment of the present disclosure includes: A shape measuring device for measuring the three-dimensional shape and orientation of a target material; a convexity detection device that detects convexities present on a surface of the target material and recognizes the positions and shapes of the convexities; a grinding device including a grinding tool for grinding the protruding portion; The grinding tool control device calculates a trajectory along which the grinding tool moves based on the measured three-dimensional shape and orientation of the target material and the detected position and shape of the convex portion, and controls the grinding device so that the grinding tool moves along the trajectory while changing the contact angle of the grinding tool with respect to the convex portion.

[0013] [2] As an embodiment of the present disclosure, in [1], a grinding reaction force measuring device for measuring a grinding reaction force received by the grinding tool from the target material; The grinding tool control device corrects the trajectory based on the measured grinding reaction force, and controls the grinding device so that the grinding tool moves along the corrected trajectory.

[0014] [3] As an embodiment of the present disclosure, in [2], the grinding tool control device includes a first grinding tool control device and a second grinding tool control device, the first grinding tool control device corrects the trajectory in a height direction based on a component in a height direction of the measured grinding reaction force, The second grinding tool control device corrects the trajectory in a direction different from the height direction based on a component in a direction different from the height direction of the measured grinding reaction force.

[0015] [4] As an embodiment of the present disclosure, in any one of [1] to [3], An inspection device is provided that inspects the surface of the target material at the position of the protrusion after the protrusion has been ground.

[0016] [5] As an embodiment of the present disclosure, in any one of [1] to [4], The grinding tool is a grindstone that rotates around a rotation axis, The grinding tool control device controls the grinding device so that the rotation axis is tilted depending on the position where the grindstone comes into contact with the protrusion.

[0017] [6] A method for grinding a convex portion according to an embodiment of the present disclosure, A shape measurement process for measuring a three-dimensional shape and orientation of the target material; a convexity detection step of detecting a convexity present on a surface of the target material and detecting a position and a shape of the convexity; The method includes a grinding process in which a trajectory along which a grinding tool for grinding the convex portion moves is calculated based on the measured three-dimensional shape and attitude of the target material and the detected position and shape of the convex portion, and the grinding tool is moved along the trajectory while changing the contact angle of the grinding tool with respect to the convex portion to grind the convex portion.

[0018] [7] As an embodiment of the present disclosure, in [6], The grinding process includes measuring the grinding reaction force that the grinding tool receives from the target material, correcting the trajectory based on the measured grinding reaction force, and moving the grinding tool along the corrected trajectory to grind the convex portion.

[0019] [8] As an embodiment of the present disclosure, in [6] or [7], After the grinding step, an inspection step is included of inspecting the surface of the target material at the position of the protrusion.

[0020] [9] A method for producing a steel product according to an embodiment of the present disclosure includes: The convex portions on the surface of the steel product, which is the target material, are ground by any one of the convex portion grinding methods [6] to [8]. Effect of the Invention

[0021] According to the present disclosure, it is possible to provide a convex portion grinding system, a convex portion grinding method, and a manufacturing method for steel products that automatically grind convex portions that occur on a wide variety of products. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of a projection grinding system according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining the reference point of the grindstone. [Diagram 3] FIG. 3 is a diagram for explaining the contact angle of the grindstone. [Figure 4] FIG. 4 is a diagram showing an example of shape measurement and protrusion extraction. [Diagram 5] FIG. 5 is a diagram showing another example of shape measurement and protrusion extraction. [Figure 6] FIG. 6 is a diagram illustrating a method for generating a machining trajectory on the xy plane. [Figure 7] FIG. 7 is a diagram illustrating an example of calculation of the z coordinate position of the processing trajectory. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of a convex portion grinding system that performs control according to the grinding reaction force. [Figure 9] FIG. 9 is a diagram showing another example of the configuration of the projection grinding system which performs control according to the grinding reaction force. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, a protrusion grinding system, a protrusion grinding method, and a manufacturing method for a steel product according to an embodiment of the present disclosure will be described with reference to the drawings.

[0024] FIG. 1 shows an example of a schematic diagram of a convex portion grinding system according to this embodiment. A convex portion 2 exists on the surface of a workpiece 1, which is an example of a target material. A three-dimensional shape measuring device 3, which is an example of a shape measuring device, measures the three-dimensional shape and posture of the workpiece 1. As the three-dimensional shape measuring device 3, for example, a camera that performs three-dimensional scanning of the workpiece 1, a shape laser sensor, etc. may be used. Based on the measurement result of the three-dimensional shape measuring device 3, an image processing device 4, which is an example of a convex portion detection device, detects the convex portion 2 existing on the surface of the workpiece 1 and recognizes the position and shape of the convex portion 2. A robot operation control device 5, which is an example of a grinding tool control device, performs inverse kinematic calculation based on the measured three-dimensional shape and posture of the workpiece 1 and the detected position and shape of the convex portion 2, and calculates a trajectory of movement of the grinding wheel 8 so that it is pressed against the position of the convex portion 2. Here, the grinding wheel 8 is a grinding tool that grinds the convex portion 2, and is provided in a grinder 7, which is an example of a grinding device. The grinder 7 is moved by a robot 6 having multiple joints. The robot 6 is controlled by a robot motion control device 5. That is, the robot motion control device 5 can control the grinder 7 via the robot 6 so that the grindstone 8 moves along the calculated trajectory. In addition, the calculated trajectory along which the grindstone 8 moves also corresponds to the motion trajectory of the robot 6.

[0025] The robot 6 operates based on the generated motion trajectory, and the grinding wheel 8 comes into contact with the workpiece 1 and the protruding portion 2 to grind the protruding portion 2. At this time, the grinding reaction force measuring device 9 measures the grinding reaction force that the grinding wheel 8 receives from the workpiece 1. The robot motion control device 5 controls the motion of the robot 6 to press the grinding wheel 8 against the workpiece 1 and the protruding portion 2 or release it so that the measured grinding reaction force becomes the target grinding reaction force. After grinding the protruding portion 2 for a certain time or until a predetermined grinding amount is reached, the robot motion control device 5 causes the three-dimensional shape measuring device 3 to measure the shape of the workpiece 1 after grinding. The robot motion control device 5 determines whether the image processing device 4 has detected the remaining protruding portion 2, and if the protruding portion 2 remains, grinding is performed again. If the protruding portion 2 does not remain, the robot motion control device 5 ends grinding. The protruding portion grinding system may include an inspection device that inspects the surface of the workpiece 1 at the position of the protruding portion 2 after the protruding portion 2 is ground. At this time, the robot operation control device 5 may perform grinding again or terminate grinding based on the inspection result from the inspection device. The inspection device may be configured to include a three-dimensional shape measuring device 3 and an image processing device 4.

[0026] Here, one of the features of the protrusion grinding system according to this embodiment is that the robot motion control device 5 controls the grinder 7 so that the grinding wheel 8 moves along a calculated trajectory while changing the contact angle of the grinding wheel 8 with respect to the protrusion 2. Grinding performed by the protrusion grinding system according to this embodiment while changing the contact angle of the grinding wheel 8 is sometimes referred to as "variable contact angle grinding."

[0027] FIG. 2 is a diagram for explaining the reference point 12 of the grindstone 8. The reference point 12 is the point where the convex portion 2 and the grindstone 8 contact each other when the grindstone 8 is in the reference position. However, if the contact portion is not a point, the reference point 12 refers to the center of the contact portion. In this embodiment, the grindstone 8 rotates around the rotation axis 10. When viewed from a viewpoint where the rotation axis 10 is perpendicular to the paper (right diagram of FIG. 2), the reference point 12 is the point where the convex portion 2 and the grindstone 8 contact each other. When viewed from a viewpoint where the rotation axis 10 is parallel to the paper (left diagram of FIG. 2), the reference point 12 is the point where the convex portion 2 and the grindstone 8 contact each other at a position t / 2 from the grindstone surface 11, which is the tip surface of the grindstone 8, assuming that the thickness of the grindstone 8 is t (reference point 12 in the thickness direction of the grindstone 8). The thickness t of the grindstone 8 is, for example, 10 to 50 mm.

[0028] FIG. 3 is a diagram for explaining the contact angle θ of the grindstone 8. FIG. 3 shows a virtual cross-sectional view in which the processing trajectory 13 and the rotation axis 10 are on the paper surface (the same plane). The processing trajectory 13 is a trajectory along which the grindstone 8 moves, calculated by the robot motion control device 5. In FIG. 3, an auxiliary line 14 perpendicular to the processing trajectory 13 is drawn, and the contact angle θ is an angle between the auxiliary line 14 and the grindstone surface 11. In the example of FIG. 3, the point where the grindstone 8 starts moving, the point where it has progressed to the midpoint of the processing trajectory 13, and the point where it has ended moving are shown as the trajectory start point 15, the trajectory midpoint 16, and the trajectory end point 17, respectively. The contact angle θ at the trajectory start point 15 is θmax. The contact angle θ at the trajectory midpoint 16 is 0. The contact angle θ at the trajectory end point 17 is θmin, which is equal to -θmax. θmax is 5°, for example. The grindstone 8 is tilted by the robot motion control device 5 so as to have a contact angle θ corresponding to the displacement from the reference point 12 in one direction (x direction in the example described later). In other words, the robot motion control device 5 controls the grinder 7 so that the rotation axis 10 is tilted according to the position where the grindstone 8 contacts the protrusion 2. The robot motion control device 5 executes contact angle change grinding so that θ changes continuously at each position of the processing trajectory 13. In the example of FIG. 3, the grindstone 8 at the trajectory midpoint 16 takes a reference posture, and the trajectory midpoint 16 corresponds to the reference point 12 in the thickness direction of the grindstone 8. In the example of FIG. 3, the grindstone 8 is tilted symmetrically around the reference point 12 like a pendulum, but may be asymmetric (θmin is not equal to -θmax).

[0029] In the contact angle change grinding, the angle at which the grinding wheel 8 contacts the protrusion 2 is changed in various ways, which promotes the falling off of abrasive grains, and since new abrasive grains are always used for grinding without clogging, high-speed grinding can be realized. The change pattern of θ is not limited to the example in FIG. 3, and can be adjusted in various ways depending on the grinding conditions such as the characteristics of the workpiece 1 and the grinding wheel 8, the rotation speed, the feed rate, and the pressing pressure. For example, by selecting an appropriate change pattern of θ depending on the type of the workpiece 1, even higher speed machining can be realized. In the example in FIG. 3, the machining path 13 is expressed as a straight line for simplification. The actual machining path 13 is often a complex curve that matches the shape of the protrusion 2, but the contact angle change grinding can be performed by making the tangent of the curved path correspond to the straight machining path 13 as in the example in FIG. 3.

[0030] (Example) 4 and 5 show an embodiment of the recognition of the convex portion 2 by shape measurement. FIG. 4 shows the recognition logic of the convex portion 2 by height. First, the image processing device 4 sets the measurement coordinate system 18 when the shape of the workpiece 1 is measured by the three-dimensional shape measuring device 3. The three-dimensional shape measuring device 3 is a camera. The measurement coordinate system 18 is set so that the height direction is the z coordinate. The workpiece shape data 19 obtained by the measurement by the three-dimensional shape measuring device 3 is general three-dimensional point cloud data. A point cloud having a z coordinate value equal to or greater than a certain value in the three-dimensional point cloud data is regarded as the convex portion shape data 20 (point cloud data of the convex portion 2). This method has a very simple recognition logic and can perform calculations at high speed. However, when the height dimension of the workpiece 1 changes frequently and when there is a large variation in the attitude and dimensions, the convex portion shape data 20 may contain inaccurate data.

[0031] FIG. 5 shows a method for obtaining convex shape data 20 as a portion not present in the comparative CAD data 21 by three-dimensional pattern matching between measured workpiece shape data 19 and comparative CAD data 21. The comparative CAD data 21 is CAD data for the workpiece 1. The image processing device 4 obtains the comparative CAD data 21 from a computer or the like that has previously designed the workpiece 1. This method is not easily affected by variations in the attitude and dimensions of the workpiece 1, changes in shape, and the like. For example, if the workpiece 1 is tilted during measurement, accurate convex shape data 20 can be obtained by comparing the comparative CAD data 21 in the same tilt in the image processing device 4.

[0032] Here, the method of Fig. 4 and the method of Fig. 5 may be selected and applied depending on the situation. For example, the image processing device 4 may switch from the method of Fig. 4 to the method of Fig. 5 when it is determined that the workpiece 1 is tilted during measurement, or when many types of workpieces 1 whose height dimensions frequently change are being measured. By selecting the method depending on the situation, the image processing device 4 can improve the recognition accuracy of the convex portion 2, handle many types of workpieces 1, and minimize the load of calculations.

[0033] 6 and 7 show an example of generating the machining trajectory 13. Fig. 6 shows a method of generating the machining trajectory 13 on the xy plane. The xy plane is a plane perpendicular to the z direction, which is the height direction. In the example of Fig. 6, the x direction corresponds to the thickness direction of the grinding wheel 8.

[0034] The robot motion control device 5 acquires the convex shape data 20 from the image processing device 4, and generates a processing trajectory 13 for grinding the convex portion 2. The robot motion control device 5 generates the processing trajectory 13 on the xy plane as follows. As shown in 1) of FIG. 6, the robot motion control device 5 selects the y coordinate position of the smallest one in the convex shape data 20. min A trajectory reference line A passes through the position and is parallel to the x-coordinate axis 0 and the y coordinate position is the largest max A trajectory reference line A that passes through and is parallel to the x-coordinate axis 1 Determine.

[0035] The robot motion control device 5 determines the trajectory reference line A as shown in FIG. 0 The locus interval lines B are drawn at equal intervals with a pitch Δp from i (i=0~N) is defined. Here, N is "((y max -y min ) / Δp)-2.

[0036] In addition, the pitch Δp is set according to the shape of the grinding wheel 8. When the diameter of the grinding wheel 8 is D and the assumed cutting depth is ta, the assumed cutting width ba is expressed as (D-2ta)tan(cos ―1 (1-2ta / D)). In this case, the pitch Δp is 0.1ba≦Δp≦ba. Here, the range of the assumed cutting depth ta is determined by performing a grinding experiment in advance, and is preferably about 0.1 to 8.0 mm.

[0037] Locus interval line B i is the intersection point B with the outer periphery of the protrusion 2 is and B. ie is the end. Here, B is is the intersection point with the smaller x-coordinate value, and B ie is the intersection point with the larger x-coordinate value.

[0038] As shown in FIG. 6(3), the robot motion control device 5 is is A point that is Δx larger in the x direction from C is In addition, the robot motion control device 5 is B ie A point that is Δx smaller in the x direction from C ie Δx is the width of a margin provided so that the grindstone 8 does not protrude from the outer periphery of the protrusion 2 when moving along the processing path 13. Δx may be determined based on the thickness of the grindstone 8. For example, Δx may be determined to be t / 2, where t is the thickness of the grindstone 8.

[0039] As shown in FIG. 6(4), if i is an even number, the robot motion control device 5 ie From C (i+1)s Grinding pass through p iIf i is an odd number, the robot motion control device 5 determines C is From C (i+1)e Grinding pass through p i Determine.

[0040] 7 is a diagram illustrating an example of calculation of the z-coordinate position of the machining path 13. The robot motion control device 5 calculates each grinding path p i Divide the top into the number of divisions between machining paths Np, and set each division point as the machining trajectory control point pg ij (j=0 to Np) The number of divisions Np between machining passes may be determined according to the machining accuracy and the measurement density of the convex shape data 20, which is point cloud data.

[0041] As an example, the number of divisions Np between machining paths is set to the x-direction dimension LB of the protrusion 2. i =√(B ie -B is ) 2 When the largest dimension (maximum value) among (i=0 to N) is LBmax, the range where LBmax / t≦Np is preferable. However, the larger the number of divisions between machining paths Np, the higher the machining accuracy becomes, but the higher the load on the robot motion control device 5 becomes. Therefore, depending on the memory resources of the robot motion control device 5 and the size of the protrusion 2, LBmax / t>Np may be used.

[0042] The robot motion control device 5 sets the processing trajectory control point pg i,j is calculated from the four closest measurement points (four point cloud data). For example, as shown in FIG. 7, if the four closest measurement points are Pm k =(x k , y k , z k ), Pm k+1 =(x k+1 , y k+1 , z k+1 ), Pm k+2 =(x k+2 , y k+2 , z k+2 ) and Pm k+3 =(x k+3 , y k+3 , z k+3 ), then pg i,j z coordinate value zgi,j is expressed by the following formula:

[0043]

number

[0044] z coordinate value zg i,j The z-coordinate values ​​of the four measurement points are calculated by weighting them according to their deviation on the xy plane. In this way, all the processing trajectory control points pg i,j The three-dimensional coordinates of are calculated. Here, the z-coordinate value zg i,j The number of measurement points used to calculate the z coordinate value zg i,j may be calculated as the average of the z coordinate values ​​of a number of nearest measurement points.

[0045] 8 and 9 show a configuration example of a convex grinding system that performs control according to the grinding reaction force. As described above, the processing trajectory 13 is determined, and the grinding wheel 8 moves on the processing trajectory 13 to perform contact angle change grinding in which the contact angle θ is changed according to the moving position in the x-axis direction. Here, in actual grinding, wear of the grinding wheel 8, deviation of the trajectory due to changing the contact angle θ of the grinding wheel 8, etc. may occur, and correction of the trajectory may be necessary. The convex grinding system according to this embodiment measures loads such as reaction forces during grinding using the grinding reaction force measuring device 9, changes the trajectory so as to achieve a preset target load, and performs feedback control. For example, the robot operation control device 5 may correct the trajectory based on the measured grinding reaction force, and control the grinder 7 so that the grinding wheel 8 moves along the corrected trajectory. Here, the range of the target load may be determined by extracting the load during appropriate grinding from performance data in past grinding, for example.

[0046] 8, for example, measurement data such as load measured by a grinding reaction force measuring device 9 is fed back to a robot motion control device 5 for a planned trajectory 24, which is the machining trajectory 13 calculated as described above. The robot motion control device 5 controls the robot 6 in real time by a trajectory control operation 26, and adjusts the actual trajectory along which the grinding wheel 8 moves so that it becomes a controlled trajectory 25.

[0047] In this embodiment, the trajectory control operation 26 is considered to be an adjustment operation in the height direction (z direction) in many cases. However, since the robot motion control device 5 controls the robot 6 that can move in three-dimensional directions, even if the adjustment operation is only in the height direction, it performs calculations for all three-dimensional directions. Therefore, the calculation load of the robot motion control device 5 may be large. Therefore, the grinding tool control device may be configured to include a first grinding tool control device and a second grinding tool control device. The first grinding tool control device corrects the trajectory in the height direction based on the component in the height direction of the measured grinding reaction force. The second grinding tool control device corrects the trajectory in a direction different from the height direction based on the component in the direction different from the height direction of the measured grinding reaction force.

[0048] FIG. 9 illustrates a case where the grinding tool control device includes a first grinding tool control device and a second grinding tool control device. The grinding wheel 8 is adjusted in the height direction by a single-axis actuator 27. The actuator control device 29 that controls the single-axis actuator 27 adjusts the height of the grinding wheel 8 in real time by a trajectory control operation 30 based on measurement data such as the load by the grinding reaction force measuring device 9 that is fed back. The actuator control device 29 corresponds to the first grinding tool control device. The robot operation control device 5 corresponds to the second grinding tool control device. The convex portion grinding system of the configuration of FIG. 9 corrects the trajectory in the height direction and the trajectory in a direction different from the height direction by different grinding tool control devices. Therefore, the calculation processing is distributed, it is possible to avoid a large calculation load on one grinding tool control device, and the trajectory can be corrected at high speed.

[0049] As described above, the convex portion grinding system according to this embodiment can automatically grind the convex portions 2 that occur in a wide variety of products with the above-mentioned configuration. Therefore, it is possible to reallocate the labor of workers who have conventionally performed grinder work to other tasks, and it is possible to improve the work efficiency of product manufacturing.

[0050] Although the embodiments according to the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications or corrections based on the present disclosure. Therefore, it should be noted that these modifications or corrections are included in the scope of the present disclosure. For example, the functions included in each component or each step can be rearranged so as not to be logically inconsistent, and multiple components or steps can be combined into one or divided. Although the embodiments according to the present disclosure have been described mainly with respect to the device, the embodiments according to the present disclosure can also be realized as a method including steps executed by each component of the device. The embodiments according to the present disclosure can also be realized as a method executed by a processor included in the device, a program, or a storage medium on which a program is recorded. It should be understood that these are also included in the scope of the present disclosure.

[0051] For example, a convex portion grinding method including the following processes may be executed by the convex portion grinding system. The convex portion grinding method may include a shape measuring step in which the three-dimensional shape measuring device 3 measures the three-dimensional shape and posture of the workpiece 1. The convex portion grinding method may include a convex portion detection step in which the image processing device 4 detects the convex portion 2 present on the surface of the workpiece 1 and detects the position and shape of the convex portion 2. The convex portion grinding method may include a grinding step in which the robot operation control device 5 calculates a trajectory along which the grinding wheel 8 for grinding the convex portion 2 moves based on the measured three-dimensional shape and posture of the workpiece 1 and the detected position and shape of the convex portion 2, and moves the grinding wheel 8 along the trajectory while changing the contact angle θ of the grinding wheel 8 with respect to the convex portion 2 to grind the convex portion 2. The convex portion grinding method may include an inspection step in which an inspection device inspects the surface of the workpiece 1 at the position of the convex portion 2. In the inspection process, the inspection device performs a three-dimensional scan or the like on the surface of the workpiece 1, and compares the measurement data with the comparative CAD data 21. If the difference in the height direction is within an allowable range, the workpiece may be judged as pass.

[0052] For example, a method for manufacturing steel products is realized in which convex parts on the surface of a steel product, which is a target material, are ground by a convex part grinding method executed by the convex part grinding system. Such a method for manufacturing steel products can automate grinding operations that have been performed by human workers in the conventional technology, thereby improving the productivity of steel products.

[0053] In the above embodiment, the image processing device 4, the robot motion control device 5, and the actuator control device 29 are each illustrated as a laptop computer, but may be other types of computers. Also, the image processing device 4, the robot motion control device 5, and the actuator control device 29 may be realized by a different computing device other than a computer, so long as they are configured to be able to communicate with each other. [Explanation of symbols]

[0054] 1 Work material (example of target material) 2 Convex 3. Three-dimensional shape measuring device (example of shape measuring device) 4. Image processing device (an example of a protrusion detection device) 5 Robot motion control device (an example of a grinding tool control device) 6. Robot 7 Grinder (an example of grinding equipment) 8 Grindstone (an example of a grinding tool) 9 Grinding reaction force measuring device 10 Rotation axis 11 Grindstone surface 12 Reference points 13 Machining trajectory 14 Auxiliary Lines 15 Trajectory start point 16 Trajectory midpoint 17 End of trajectory 18 Measurement coordinate system 19 Workpiece shape data 20 Convex shape data 21 CAD data for comparison 24 Planned trajectory 25 Control Locus 26 Trajectory control operation 27 Single-axis actuator 29 Actuator control device 30 Trajectory control operation

Claims

1. A shape measuring device for measuring the three-dimensional shape and orientation of a target material; a convexity detection device that detects convexities present on a surface of the target material and recognizes the positions and shapes of the convexities; a grinding device including a grinding tool for grinding the protruding portion; a grinding tool control device that calculates a trajectory along which the grinding tool moves based on the measured three-dimensional shape and attitude of the target material and the detected positions and shapes of the convex portions, and controls the grinding device so that the grinding tool moves along the trajectory while changing a contact angle of the grinding tool with respect to the convex portions, The grinding tool is a grindstone, A convex portion grinding system, in which the point at which the convex portion and the grinding tool contact each other when the grinding tool is in a standard posture is used as a reference point, and the contact angle changes continuously at each position to which the grinding tool moves along the trajectory, and has a symmetrical inclination around the reference point.

2. a grinding reaction force measuring device for measuring a grinding reaction force received by the grinding tool from the target material; The convex portion grinding system according to claim 1 , wherein the grinding tool control device corrects the trajectory based on the measured grinding reaction force and controls the grinding device so that the grinding tool moves along the corrected trajectory.

3. the grinding tool control device includes a first grinding tool control device and a second grinding tool control device, the first grinding tool control device corrects the trajectory in a height direction based on a component in a height direction of the measured grinding reaction force, The convex portion grinding system according to claim 2 , wherein the second grinding tool control device corrects the trajectory in a direction different from the height direction based on a component of the measured grinding reaction force in a direction different from the height direction.

4. The projection grinding system according to claim 1 , further comprising an inspection device that inspects the surface of the target workpiece at the position of the projection after the projection is ground.

5. The grinding tool is a grindstone that rotates around a rotation axis, The protrusion grinding system according to claim 1 , wherein the grinding tool control device controls the grinding device so that the rotation axis is tilted depending on a position where the grindstone comes into contact with the protrusion.

6. A shape measurement process for measuring a three-dimensional shape and orientation of the target material; a convexity detection step of detecting a convexity present on a surface of the target material and detecting a position and a shape of the convexity; a grinding process for calculating a path along which a grinding tool for grinding the convex portion moves based on the measured three-dimensional shape and attitude of the target material and the detected position and shape of the convex portion, and for grinding the convex portion by moving the grinding tool along the path while changing a contact angle of the grinding tool with respect to the convex portion, The grinding tool is a grindstone, a contact angle that changes continuously at each position to which the grinding tool moves along the trajectory and has a symmetrical inclination around the reference point, the contact angle being determined by a point at which the grinding tool contacts the convex portion when the grinding tool is in a reference posture.

7. 7. The method for grinding a convex portion according to claim 6, wherein the grinding step comprises measuring a grinding reaction force that the grinding tool receives from the target material, correcting the trajectory based on the measured grinding reaction force, and moving the grinding tool along the corrected trajectory to grind the convex portion.

8. The method for grinding a protrusion according to claim 6 , further comprising, after the grinding step, an inspection step of inspecting the surface of the target workpiece at the position of the protrusion.

9. A method for manufacturing an iron and steel product, comprising grinding convex portions on a surface of the iron and steel product as the target material by the method for grinding convex portions according to any one of claims 6 to 8.

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