Deck plate cutting device

Abstract

This invention provides a deck plate cutting device that enables shape measurement less affected by the illumination of the work site and the plating treatment of the deck plate, and allows for skill-less operation. [Solution] The present invention includes a robot arm 20 equipped with a cutting means 50 for cutting a deck plate and moving it, a laser sensor 40 that measures the distance of the deck plate surface and acquires the positional relationship with the cutting point in an xyz coordinate system with the arm's main body position as the origin, and measures the shape of the cutting point on the deck plate, and an operation terminal 60 that creates the inclination of the cutting means relative to the cutting point and the movement route of the cutting means to cut at a predetermined distance from the cutting point based on the shape of the cutting point, and controls the cutting by cutting with the cutting means while moving the arm along the movement route. When the laser sensor measures a cutting point that spans an uneven part of the deck plate, it moves back and forth at a predetermined angle with respect to a vertical line perpendicular to the main surface of the deck plate and acquires measurement data by combining the forward and return paths.

Description

TECHNICAL FIELD

[0001] The present invention particularly relates to a cutting device for cutting deck plates that form the ceiling of concrete buildings. BACKGROUND ART

[0002] Deck plates are attached to the ceilings of concrete buildings such as nuclear power plants. A deck plate is a steel plate of a predetermined thickness that is press-formed into an uneven shape with continuous corners and inclined surfaces to impart strength. Such a ceiling forming method involves laying deck plates and pouring concrete over them to solidify. In addition, various pipes, ducts and the like may be attached to the ceiling, and are supported using steel brackets. Brackets that bear the load of heavy objects are reinforced by being attached to embedded hardware embedded between the deck plate and the concrete. For this embedded hardware, it is necessary to cut and remove the deck plate at the embedding location after the concrete has solidified to expose the surface. This work had to be performed in an upward working posture, placing a heavy burden on workers.

[0003] As an apparatus for cutting and removing such deck plates, the technique disclosed in Patent Document 1 is provided with a cutting means, a camera, and a laser sensor on a robot arm, and creates a movement route for the cutting means that cuts at a predetermined distance from the cutting location with the inclination of the cutting means relative to the cutting location, based on the shape of the cutting location, and performs control to perform cutting while moving the robot arm along the movement route.

[0004] However, in order to make the camera recognize the marking line at the cutting location, it is necessary to perform HSV color extraction and RGB color extraction on the camera image, but at the work site, which is indoors with low illuminance, the color extraction settings have to be changed manually. This work caused variations in color extraction settings depending on the worker, making the recognition accuracy of the marking lines unstable. Furthermore, while laser sensors are designed to detect reflected light by shining a laser perpendicularly onto the surface being illuminated, when measuring corners or inclined surfaces of deck plates, the laser would be scattered irregularly by the plated corners and inclined surfaces, making it impossible to measure corners and inclined surfaces. Furthermore, when moving the robot arm along the designated route, if the robot arm body or measuring instruments collide with the deck plate, a safety device will activate and stop the arm, or the instruments may be damaged. Therefore, the arm had to be operated in a way that avoided collisions, which made the adjustment process difficult. Furthermore, there was a problem in that the control system's programming was complex and could only be handled by skilled personnel. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2024-126159 [Overview of the project] [Problems that the invention aims to solve]

[0006] The problem that this invention aims to solve, in view of the problems of the prior art described above, is to provide a deck plate cutting device that enables shape measurement less affected by the illumination of the work site and the plating treatment of the deck plate, and that allows for skill-less operation. [Means for solving the problem]

[0007] As a first means to solve the above problem, the present invention provides a robotic arm equipped with a cutting means for cutting a deck plate and moving it, A laser sensor measures the distance of the deck plate surface to obtain the positional relationship with the cutting point in an xyz coordinate system with the robot arm's main body as the origin, and measures the shape of the cutting point on the deck plate. Based on the shape of the cutting location, the cutting means's inclination relative to the cutting location and the movement route of the cutting means, which cuts at a predetermined distance from the cutting location, are created, and the operation terminal is provided to control the cutting by the cutting means while moving the robot arm along the movement route. The objective is to provide a deck plate cutting device characterized in that, when measuring a cutting location that spans an uneven portion of the deck plate, the laser sensor is tilted at a predetermined angle with respect to a vertical line perpendicular to the main surface of the deck plate and moves back and forth to acquire measurement data combining the forward and return movements. According to the first method described above, accurate shape measurement of the deck plate can be achieved, which is less affected by the illumination of the work site and the plating treatment of the deck plate.

[0008] As a second means for solving the above problems, the present invention provides a deck plate cutting device characterized in that, in the first means, when measuring the shape, the laser sensor interferentially measures a range that spans at least two uneven areas of the deck plate including the cutting location, parallel to the main surface, at a predetermined distance from the deck plate. According to the second method described above, by using the measurement data from interference measurement to create a movement route, it is possible to prevent the robot arm or measuring equipment from coming into contact with the deck plate during the cutting operation, which would activate the safety device and cause the robot to stop, or to prevent the measuring equipment from malfunctioning.

[0009] As a third means for solving the above problems, the present invention provides a deck plate cutting device characterized in that, in the second means, when measuring the shape, the cutting means moves from below to above the vertex of the cutting location, stops when the tip contacts the vertex and the drive motor of the robot arm reaches a predetermined torque, and corrects the height position of the measurement data. According to the third method described above, even if the measurement data of the laser sensor is misaligned (error) due to the influence of ambient temperature, the misalignment of the measurement data can be corrected by correcting the measurement data with the actual height position data obtained by the cutting means.

[0010] As a fourth means for solving the above problems, the present invention provides a deck plate cutting device characterized in that, in any one of the first to third means, the operating terminal is equipped with application software that instructs the operator on the work content in the order of the process, and the operator can perform the work content of each process by operating a selection button at each process. According to the fourth method described above, conventionally, workers directly input numerical parameters and other information into a dedicated operation program. However, by introducing application software that displays the work content in a sequential order and allows workers to select operations for each step, the operation becomes skill-less and the work can be performed easily.

[0011] As a fifth means for solving the above problems, the present invention provides a deck plate cutting device characterized in that, in the fourth means, the application software creates a three-dimensional graph of the measurement data of the cutting location and the movement route created by the operation terminal, and displays it on the operation terminal. According to the fifth method described above, the measurement data of the cutting location and the created movement route can be easily verified visually by displaying them in a 3D graph. Therefore, when cutting work is performed using a movement route created with measurement data that was incorrectly acquired due to diffuse reflection or other reasons, problems such as contact of the robot arm can be reliably avoided. [Effects of the Invention]

[0012] According to the present invention, accurate shape measurement of deck plates can be achieved, which is less affected by the illumination of the work site and the plating treatment of the deck plates. Furthermore, it enables skill-less control operation by the worker. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram of the configuration of the deck plate cutting device of the present invention. [Figure 2] This is diagram 1 illustrating the travel route. [Figure 3] It is an explanatory diagram 2 of the movement route. [Figure 4] It is an explanatory diagram 3 of the movement route. [Figure 5] It is an explanatory diagram 4 of the movement route. [Figure 6] It is an explanatory diagram 5 of the movement route. [Figure 7] It is an explanatory diagram 6 of the movement route. [Figure 8] It is an explanatory diagram 7 of the movement route. [Figure 9] It is a process diagram of the deck plate cutting method of the present invention. [Figure 10] It is an explanatory diagram of the vertex of the cutting position. [Figure 11] It is an explanatory diagram 1 of laser measurement of the uneven portion. [Figure 12] It is an explanatory diagram 2 of laser measurement of the uneven portion. [Figure 13] It is an explanatory diagram 3 of laser measurement of the uneven portion. [Figure 14] It is an explanatory diagram 1 of laser measurement of the flat portion. [Figure 15] It is an explanatory diagram of calibration of the laser sensor. [Figure 16] It is an explanatory diagram of interference region measurement using a laser sensor. [Figure 17] It is an explanatory diagram of the application software displayed on the operation terminal. [Figure 18] It is a three-dimensional graph of measurement data of the cutting position and the movement route. [Modes for Carrying Out the Invention]

[0014] Hereinafter, an embodiment of the deck plate cutting apparatus of the present invention will be described in detail with reference to the drawings.

[0015] [Deck plate cutting apparatus 10] Figure 1 is a schematic configuration diagram of the deck plate cutting apparatus of the present invention. The deck plate cutting device 10 of the present invention (hereinafter simply referred to as the cutting device) is a device that cuts a portion of the deck plate 11 into an arbitrary shape in order to expose the embedded metal 12 embedded between the deck plate 11 and the concrete. The cutting device 10 includes a robot arm 20 equipped with a cutting means for cutting the deck plate 11 and moved by the arm 22, a laser sensor 40 that measures the distance of the deck plate surface and acquires the positional relationship with the cutting point in an xyz coordinate system with the robot arm 20's main body position as the origin, and measures the shape of the cutting point, and an operation terminal 60 that creates the inclination of the cutting means 50 relative to the cutting point and a movement route for the cutting means 50 to cut at a predetermined distance from the cutting point based on the shape of the cutting point, and controls the robot arm 20 to move along the movement route and cut with the cutting means 50.

[0016] The robot arm 20 is controlled by the control panel 21 to automatically cut the deck plate 11 at the designated cutting points. The robot arm 20 is a multi-axis robot arm consisting of a base body 24 and multiple arms 22 connected via multiple axes. Multiple motors are arranged between the arms 22, and the operation of each motor allows the tip arm 22 to move freely forward, backward, left, and right with respect to the base body 24.

[0017] The laser sensor 40 is a sensor that measures the distance to a target by shining a laser beam towards the target and receiving the laser beam reflected from the target. The laser sensor 40 is attached to the cutting torch 52 of the cutting means 50, which will be described later, and is attached to the tip of the arm 22. The laser sensor 40 is equipped with a laser control means, which is a computer equipped with a memory that stores a program for measuring the shape of the cutting area and a central processing unit (CPU). The laser control means measures the shape of the target to be cut using distance measurement data acquired by scanning the laser along the markings and transmits it to the operation terminal 60, which will be described later. Furthermore, after the device is installed at the work site, the laser sensor 40 first measures the distance to the deck plate surface and acquires the positional relationship with the cutting point in an xyz coordinate system with the base body 24 of the robot arm 20 as the origin (0,0,0).

[0018] A cutting means 50 is attached to the very tip of the arm 22. The cutting means 50 uses a thermal cutting machine to cut the deck plate 11 at the cutting point. Examples of thermal cutting machines include plasma cutting machines and gas cutting machines. Thermal cutting can cut by melting the material using the generated thermal energy, so it can cut the deck plate 11 without considering its thickness or material. The thermal cutting machine consists of a cutting torch 52 attached to the tip of the arm 22 and a cutting machine body 54 connected to the cutting torch 52 via a cable.

[0019] The operating terminal 60 is electrically connected to the control panel 21 of the robot arm 20, the laser sensor 40, and the cutting machine body 54 of the cutting means 50. The operating terminal 60 is a tablet-type personal computer (PC) equipped with a memory that stores various programs such as the control program for the robot arm 20 and the movement route creation program for the cutting means 50, as well as application software for operation, a storage unit for storing various data, and a central processing unit (CPU). The operating terminal 60 is equipped with a keyboard and a display (such as a touch panel) that allows for various operations and inputs.

[0020] The movement route creation program is a program that creates a movement route for the cutting means 50 (cutting torch) attached to the tip of the arm 22 as it moves along the vertices 14 of the cutting area 13 (for example, in the case of a rectangular cutting area, these are the four corners, and the corners are positioned on the convex plane of the deck plate 11). Figures 2-8 are explanatory diagrams 1-7 of the movement route. In these figures, as an example, the case where the cutting point is a single line spanning the unevenness of the deck plate 11 is explained. The coordinate system used is an xyz coordinate system with the base body 24 of the robot arm 20 as the origin. The measurement data uses measurement data points (for example, all 11 points) obtained by converting the distance measurement data of the laser sensor 40 into an xyz coordinate system (see Figure 2, the arrows in the figure indicate the direction of movement of the cutting torch). The procedure for creating the movement route for Pn(Xn,Yn,Zn) is explained below.

[0021] The movement route should ideally be such that the cutting torch 52 attached to the tip of the arm 22 passes through a location with a predetermined distance L (approximately several mm) away from the cutting point, while the cutting torch 52 is facing a specific direction, for example, perpendicular to or at a near-perpendicular angle to the deck plate surface to be cut. Such a movement route can be created by generating a 3D vector from the measurement data and performing calculations. The created movement route has the tip coordinates Pn'(xn',yn',zn') and direction vector Rn(φn,θn,ψn) of the cutting torch corresponding to each measurement data point (for the nth data point) registered (see Figure 3). The information needed to determine the direction vector R is to assume that the desired direction vector R is a "vector perpendicular to the deck plate." Therefore, to find the direction vector R, two vectors curved in the plane of the deck plate 11 are needed. With two vectors, the direction vector R can be found by calculating the cross product of the vectors (see Figure 4).

[0022] The two vectors are determined as follows: First, assuming that all measurement data lies on a plane because the cutting line is on a straight line, a normal vector N is created relative to the plane. Vector N is a vector parallel to the actual plane of the deck plate 11. Second, with the movement direction of the cutting torch 52 fixed, a movement direction vector M is created at each measurement data point. The movement direction vector M is a vector parallel to the surface of the deck plate 11 (see Figure 5). The direction vector R is obtained by normalizing the result of the cross product calculation of the normal vector N and the direction of movement vector Mn. R = (N × Mn) / |N × Mn| The tip coordinates Pn' of the cutting torch 52 can be determined by advancing it a predetermined distance L in the negative direction vector Rn from Pn (see Figure 6). Pn' = Pn - L·R

[0023] Once the tip coordinates Pn' and direction vector Rn of the cutting torch are determined, the position and orientation of the end effector of the robot arm 20, the cutting torch 52, and the laser sensor 40 (hereinafter referred to as the end effector) are also determined. At this time, depending on the direction vector Rn, the end effector may interfere with the deck plate 11 (see Figure 7). To avoid this interference, shape measurement is performed on two uneven areas of the deck plate 11 around the cutting point. In this embodiment, shape measurement is performed by scanning the area of ​​two uneven areas of the deck plate with the laser sensor 40 when the cutting line crosses the uneven areas of the deck plate 11. Note that interference does not occur on the flat surface of the convex part of the deck plate 11 when cutting, so interference measurement does not need to be performed there. Interference determination is performed using the shape measurement results and the model of the end effector. Any method can be used for interference determination, for example, by checking whether the shape measurement result data exists inside the model of the end effector. At this time, if the deck plate 11 and the end effector are interfering, the orientation of the end effector must be changed, i.e., the direction vector Rn must be changed, in order to avoid the interference.

[0024] In this invention, the direction vector Rn' that does not interfere with the deck plate 11 is obtained by iterative calculation by tilting the direction vector Rn by an angle θ. First, interference is checked in Rn. If interference occurs, the vector is tilted by dθ (for example, 1° in the Mn direction) and the interference check is performed again. If interference still occurs after iterative calculation up to the changeable angle θmax (for example, 45°), the vector is tilted by -dθ from Rn and the interference check is performed again. In this way, by repeating the process until the angle θ is such that the shape measurement result and the end-effector model do not interfere, the direction vector Rn' that does not interfere with the deck plate 11 and the end-effector can be obtained (see Figure 8). Figures 2 to 8 show specific examples where the cut is a single line spanning the irregularities of the deck plate 11. However, if the cut is rectangular, a movement route can be created by combining, for example, two straight lines spanning the irregularities and two straight lines on a flat surface, for a total of four straight lines.

[0025] Therefore, the method for creating a travel route from point 1 to n points (all n points) can be determined by the following (1) to (5). (1) A normal vector N is created using all measurement data (e.g., a single line) from the laser sensor 40. (2) Create a movement direction vector Mn for each measurement data point. (3) At each measurement data point, the normal vector N and the direction vector Mn are used to create the direction vector Rn by cross product calculation. (4) Calculate the torch tip coordinates Pn' from the measurement point coordinates Pn, the direction vector R, and the predetermined distance L. (5) Perform interference detection, and if interference occurs, set the direction vector Rn to a vector tilted by an angle θ. (2) to (5) are repeated for all n numbers, i.e., n times. (6) The torch tip coordinates Pn' and direction vector Rn are registered as the movement route of the robot arm 20.

[0026] [How to cut deck plates] The method for cutting a deck plate according to the present invention, based on the above configuration, will be described below. Figure 9 is a process diagram of the method for cutting a deck plate according to the present invention. Figure 10 is an explanatory diagram of the vertices of the cutting points. Figure 11 is explanatory diagram 1 of laser measurement of uneven surfaces. Figure 12 is explanatory diagram 2 of laser measurement of uneven surfaces. Figure 13 is explanatory diagram 3 of laser measurement of uneven surfaces. Figure 14 is explanatory diagram 1 of laser measurement of flat surfaces. Figure 15 is an explanatory diagram of laser sensor calibration. Figure 16 is an explanatory diagram of interference region measurement using a laser sensor.

[0027] The operating terminal 60 can be, for example, a tablet terminal equipped with application software that instructs the worker on the work content in the order of steps, and allows the worker to execute the work content of each step by operating selection buttons. Figure 17 is an explanatory diagram of the application software displayed on the operating terminal. As shown in the figure, when the application software of the present invention is launched and displayed on the screen of the operating terminal 60, the order of work steps is displayed, and when each step is selected, the work content of that step is presented. The worker performs the work according to the work content, and when the selection button is pressed, the work can be executed. In the past, workers directly input numerical parameters etc. to a dedicated operation program, but by introducing application software that shows the work content in the order of steps and allows the worker to perform the work content of each step in a selection format, the operation can be made skill-less and the work can be made easy.

[0028] (Step 1) Mark the cutting points 13 on the deck plate 11. If the cutting points 13 are rectangular, mark the four corners, i.e., the vertices 14 located on the plane of the convex part of the deck plate 11 (see Figure 10). (Step 2) The cutting device 10 is transported to the work site. The cutting device 10 is lightweight and portable, so it can be easily transported by workers. (Step 3) The cutting device 10 is installed at the work site using a fixing base.

[0029] (Step 4) The cutting operation of the cutting device 10 is started. The robot arm 20 is operated to move the laser sensor 40 directly below the marker, that is, so that the laser beam hits it perpendicularly, and the laser beam is shone onto all (four points if the cutting area is rectangular) markers (vertices 14) to perform positioning and acquire coordinate data (see Figure 10). This process allows the cutting area 13 to be recognized without being affected by the illumination of the work site. The deck shape is measured using the laser sensor 40. The laser sensor 40 is moved by operating the robot arm 20.

[0030] Normally, the laser sensor 40 can efficiently detect reflected light when the laser is shone perpendicularly to the main surface. However, when there are irregularities such as those on the deck plate 11, shining the laser on the inclined surface between the protrusions and recesses will cause diffuse reflection. Therefore, when the cutting line crosses the irregularities of the deck plate 11, the first (forward) measurement is performed with the laser sensor 40 tilted at a predetermined angle, for example, 20° to 30° (see Figure 11). At this time, the shape of one of the two inclined surfaces of the deck plate 11 can be measured. Next, the laser sensor 40 is tilted to the opposite side (-20° to -30°) around a vertical line perpendicular to the main surface of the deck plate 11, and the second (return) measurement is performed (see Figure 12). At this time, the shape of the other of the two inclined surfaces of the deck plate 11 can be measured. Therefore, by combining (overlapping) the measurement data from the first and second measurements, the shape of the irregularities can be measured (see Figure 13). In the case of a cutting line that spans the uneven surface of the deck plate 11, the corners of the deck plate can be accurately measured by reciprocating motion measurement, and a reliable cutting path can be generated.

[0031] If the cutting line lies on the plane of a convex or concave portion of the deck plate 11, measurement can be performed by irradiating the main surface perpendicularly with a laser as usual (see Figure 14). Next, the laser sensor 40 is calibrated because the measured values ​​may be affected by factors such as ambient temperature. The cutting torch 52 is moved directly below the vertex 14 of the cutting point 13, and then moved from below the vertex 14 toward the vertex 14. The cutting torch 52 is stopped when the tip of the cutting torch 52 contacts the vertex 14 and the drive motor of the robot arm 20 reaches a predetermined torque (see Figure 15). The height coordinate of the cutting torch 52 is determined. This operation allows for correction of any discrepancies (errors) in the laser sensor's measurement data due to factors such as ambient temperature, by correcting the measurement data with the actual height position data obtained by the cutting means 50.

[0032] To check for obstacles around the cutting point 13, the shape of the deck plate 11 is measured over two uneven areas. If the cutting line crosses the uneven areas of the deck plate 11, the area of ​​the deck plate 11 over two uneven areas is scanned with the laser sensor 40 to measure its shape. Note that interference measurement is not required on the flat surface of the protrusions, as no interference occurs during cutting. Alternatively, the shape measurement may be performed by moving the laser sensor 40 in a spiral direction expanding from the center of the cutting point 13 (see Figure 16).

[0033] Once the shape measurement of the cutting area 13 is complete, a movement route for the robot arm 20 equipped with the cutting torch 52 is created. The movement route is created using the movement route creation program described above. The created movement route can be displayed in advance on the application software of the work terminal before the cutting work begins. Figure 18 is a 3D graph of the measurement data of the cutting location and the movement route. The application software of the present invention can create a 3D graph of the measurement data of the cutting location and the movement route created on the operation terminal 60 and display it on the operation terminal 60. This allows the operator to easily verify the measurement data of the cutting location and the created movement route by visual inspection. Therefore, problems that occur when cutting work is performed using a movement route created with incorrectly acquired measurement data can be reliably avoided.

[0034] The robot arm 20 begins moving according to the created movement route. The cutting is completed by adjusting the distance between the deck plate 11 and the tip of the cutting means 50 (cutting torch 52) and cutting along the created movement route. According to this invention, accurate shape measurement of deck plates can be achieved, which is less affected by the illumination of the work site and the plating treatment of the deck plates. Furthermore, it enables skill-less control operation by the worker.

[0035] Preferred embodiments of the present invention have been described above. However, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the invention. Furthermore, the present invention is not limited to the combinations shown in the embodiments, but can be implemented using various combinations. [Explanation of symbols]

[0036] 10. Deck plate cutting device 11 Deck Plates 12 Embedded metal 13 Cutting points 14 vertices 20 Robot Arms 21 Control Panel 22 Arms 24 Base Unit 40 Laser Sensors 50 Cutting means 52 Cutting Torch 54 Cutting machine body 60 Operating terminals

Claims

1. A robotic arm equipped with a cutting mechanism for cutting deck plates and for moving them, A laser sensor measures the distance of the deck plate surface to obtain the positional relationship with the cutting point in an xyz coordinate system with the robot arm's main body as the origin, and measures the shape of the cutting point of the deck plate. Based on the shape of the cutting location, the cutting means's inclination relative to the cutting location and the movement route of the cutting means, which cuts at a predetermined distance from the cutting location, are created, and the operation terminal is provided to control the cutting by the cutting means while moving the robot arm along the movement route. The deck plate cutting device is characterized in that, when measuring a cutting location that spans an uneven portion of the deck plate, the laser sensor is tilted at a predetermined angle with respect to a vertical line perpendicular to the main surface of the deck plate and moves back and forth to acquire measurement data combining the forward and return movements.

2. A deck plate cutting device according to claim 1, A deck plate cutting device characterized in that, during the shape measurement, the laser sensor interferometrically measures a range spanning at least two uneven areas of the deck plate including the cutting location, while maintaining a predetermined distance from the deck plate and parallel to the main surface.

3. A deck plate cutting device according to claim 2, A deck plate cutting device characterized in that, during the shape measurement, the cutting means moves from below to above the apex of the cutting location, stops when the tip contacts the apex and the drive motor of the robot arm reaches a predetermined torque, and corrects the height position of the measurement data.

4. A deck plate cutting device according to any one of claims 1 to 3, The deck plate cutting apparatus is characterized in that the operating terminal is equipped with application software that instructs the operator on the work content in the order of the process, and the operator can perform the work content of each process by operating a selection button at each process.

5. A deck plate cutting device according to claim 4, The deck plate cutting device is characterized in that the application software creates a three-dimensional graph of the measurement data of the cutting location and the movement route created on the operating terminal, and displays it on the operating terminal.

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