JP7722337B2 - Calibration method for three-dimensional shape measuring equipment, three-dimensional shape measuring device, and automatic processing device - Google Patents

Description

The present invention relates to a calibration method for a three-dimensional shape measuring instrument, a three-dimensional shape measuring device, and an automatic processing device.

The plate refining process in steelworks is a process for refining metal (steel, aluminum, titanium) plates as objects to be measured, and in this plate refining process, the plates are cut by thermal cutting such as gas cutting, laser cutting, plasma cutting, etc. After cutting the plates, the longitudinal, width, and diagonal dimensions and flatness of the cut plates are measured.
Conventional methods for measuring the dimensions and flatness of thick plates after cutting are still often performed manually using tools such as tape measures and height gauges. This manual measurement of thick plates after cutting requires heavy physical labor, and poses the risk of falls due to poor work footing, and the risk of collisions and pinch-in injuries due to interference with the cutting equipment when working inside the line. Furthermore, manual measurement raises concerns about individual differences and human error in measurement accuracy, as well as the issue of a limited number of measurement points.

In order to solve these problems, a three-dimensional measuring device for an object using a light-section method has been proposed in the past, as shown in Patent Document 1, for example, which automatically measures the dimensions and flatness of a thick plate using a three-dimensional measuring device.
The three-dimensional measuring device disclosed in Patent Document 1 includes a table on which an object is placed, actuators provided on both ends of the table, multiple slit light sources installed to illuminate the object from multiple directions at right angles, and multiple cameras that capture images of the light reflected from the object. The three-dimensional measuring device also includes a portal frame that supports the multiple pairs of slit light sources and cameras at predetermined positions and has a movement mechanism at its end that moves along the actuators. The three-dimensional measuring device also includes multiple image processing devices that process image data from each camera, and a computer that processes the three-dimensional measurement data from each image processing device and controls the control unit.

Furthermore, as a calibration device for an optical head portion in a three-dimensional shape measurement device using the light section method, for example, the device disclosed in Japanese Patent Application Laid-Open No. 2003-222114 is known.
The calibration device for a three-dimensional shape measurement device disclosed in Patent Document 2 includes a detachable optical head equipped with a slit light source and a camera, and a guide unit that allows the detached optical head to move in a predetermined orientation. The calibration device has multiple rows of calibration blocks with known dimensions arranged in a descending staircase pattern in the direction of movement of the optical head. The optical head is moved along the guide unit of the calibration device, and each calibration block is photographed with the camera while irradiated with slit light from the slit light source. The camera then extracts bright lines of the slit light from the images. The coordinates of the extracted bright lines of the slit light on the image plane are calculated, and the coordinates of the bright lines in real space are calculated from the corresponding positions of the calibration blocks and the camera. These coordinates are then stored as a mapping table. When measuring an object using the light-section method, the coordinates of the bright lines of the slit light on the image plane are calculated. The coordinates of the bright lines in real space in the image captured by the camera are then calculated from the correspondence between the coordinates of each bright line on the image plane and the coordinates in real space stored in the mapping table, and the captured image is corrected.

Patent No. 3375439 JP 2007-33039 A

However, in the conventional three-dimensional measuring device disclosed in Patent Document 1, when the slit light source and camera are attached to the portal frame, attachment errors may occur in the direction of travel of the portal frame (x direction), the horizontal direction (y direction) perpendicular to the direction of travel, and the vertical direction (z direction) perpendicular to the direction of travel and the horizontal direction. If these attachment errors occur in the slit light source and the camera, errors may occur in the image data captured by the camera.
On the other hand, the calibration device for the optical head part in the three-dimensional shape measurement device using the light-section method shown in Patent Document 2 can calibrate the installation errors of the slit light source and the camera with respect to the optical head in three axes (x-axis, y-axis, and z-axis directions).

However, in the calibration device for the three-dimensional shape measurement device using the light-section method shown in Patent Document 2, the installation errors for the slit light source and the camera optical head in all three axial directions (x-axis, y-axis, and z-axis directions) are calculated at once, which poses problems such as a complex configuration of the calibration device and not being very accurate in calculating the installation errors in the three axial directions.
Therefore, the present invention has been made to solve the problems of the related art, and its object is to provide a calibration method for a three-dimensional shape measuring device, a three-dimensional shape measuring device, and an automatic machining device that can accurately calculate installation errors around multiple installation direction axes of a three-dimensional measuring device using a simple device configuration.

In order to solve the above-mentioned problems, one aspect of the present invention provides a method for calibrating a three-dimensional shape measuring device that calibrates the installation error of a three-dimensional shape measuring device that measures the three-dimensional shape of an object to be measured, and includes a calculation step in which a calibration device calculates, for each of a plurality of installation direction axes of the three-dimensional shape measuring device, an installation error around the plurality of installation direction axes using a different calculation method for each of the installation direction axes.
Furthermore, a three-dimensional shape measuring apparatus according to another aspect of the present invention is characterized in that it includes a three-dimensional shape measuring device that measures the three-dimensional shape of an object to be measured, and a calibration device that calculates installation errors around multiple installation direction axes of the three-dimensional shape measuring device using different calculation methods for each of the installation direction axes.

An automatic machining device according to another aspect of the present invention comprises a three-dimensional shape measuring device that measures the three-dimensional shape of a workpiece; a three-dimensional shape measuring device that includes a calibration device that calculates installation errors about multiple installation direction axes of the three-dimensional shape measuring device using different calculation methods for each of the multiple installation direction axes; and a machining device that processes the workpiece, wherein the three-dimensional shape measuring device measures the three-dimensional shape of the workpiece at least either before or after processing by the machining device.

The calibration method for a three-dimensional shape measuring device, the three-dimensional shape measuring device, and the automatic machining device according to the present invention enable highly accurate calculation of mounting errors around multiple mounting direction axes of a three-dimensional measuring device using a simple device configuration.

1 is a schematic configuration diagram of an automatic cutting device as an automatic processing device according to an embodiment of the present invention. FIG. 2 is a block diagram of a control device in the automatic cutting device shown in FIG. 1 . 2A and 2B are diagrams illustrating the mounting angle adjustment mechanism of the distance sensor in the automatic cutting device shown in FIG. 1 , in which FIG. 2A is a diagram illustrating the mounting angle adjustment of the distance sensor around two horizontal axes (y _-s axes), FIG. 2B is a diagram illustrating the mounting angle adjustment of the distance sensor around a vertical axis (z- _s axis), and FIG. 2C is a diagram illustrating the mounting angle adjustment of the distance sensor around one horizontal axis (x _-s axis). This explains a method for measuring the three-dimensional shape of a thick plate using an automatic cutting device, where (a) is a plan view of a thick plate placed on the base of the automatic cutting device, and (b) is a plan view explaining how the distance sensor moves in a zigzag pattern as indicated by arrow A in a plan view from the state shown in (a) to measure the three-dimensional shape of the thick plate. 1A is an explanatory diagram of a state in which the distance sensor irradiates a laser beam onto the upper surface of a surface plate as a calibration member, and _FIG . 1B is an explanatory diagram of a state in which the distance sensor attached to a tool irradiates a laser beam onto the upper surface of a surface plate as a calibration member, with an installation error Δθy around the horizontal two axes (y _s axes). 1A is an explanatory diagram illustrating a method for calculating an installation error of a mounting angle of a distance sensor about a single horizontal axis (x-axis _{, s-} axis), in which FIG. 1A is an explanatory diagram illustrating a state in which the distance sensor is irradiating laser light onto two horizontal surfaces of a calibration block as a calibration member placed on a surface plate, FIG. 1B is an explanatory diagram illustrating a state in which the distance sensor attached to a tool is irradiating laser light onto the two horizontal surfaces of the calibration block in a state in which there is an installation error Δθx about the single horizontal axis ( _x -axis, _s- axis), and FIG. 1C is a diagram illustrating the geometric relationship between a known height difference h between the two horizontal surfaces of the calibration block and a height difference herr between the two horizontal surfaces of the calibration block when the distance sensor attached to the tool is irradiating laser light onto the two horizontal surfaces of the calibration block in a state in which there is an installation error Δθx about the single horizontal axis (x-axis, s-axis). 1A is an explanatory diagram illustrating a method for calculating an installation error of a distance sensor about a vertical axis (zs _- axis), in which (a) is an explanatory diagram illustrating a state in which the distance sensor is irradiating laser light onto two horizontal surfaces of a calibration block as a calibration member placed on a surface plate, (b) is a plan view of the distance sensor attached to the tool with an installation error Δθz about the vertical axis ( _zs- axis), (c) is an explanatory diagram illustrating a state in which the distance sensor attached to the tool measures the calibration block along measurement paths a and b in two different directions with an installation error Δθz about the vertical axis (zs _- axis), and (d) is a diagram illustrating a method for calculating an installation angle at which the two coordinate transformation values match by superimposing two coordinate transformation values for two three-dimensional shape measurement data obtained by measuring the calibration block along measurement paths a and b in two different directions using the method in (c). 10 is a flowchart illustrating a process for calculating an installation error around two horizontal axes (y-axis _{and s} -axis) of a distance sensor using a three-dimensional shape measuring device. 10 is a flowchart illustrating a process for calculating an installation error around a horizontal axis ( _xs axis) of a distance sensor using a three-dimensional shape measuring device. 10 is a flowchart illustrating a process for calculating an installation error around a vertical axis ( _zs axis) of a distance sensor using a three-dimensional shape measuring device. FIG. 10 is a plan view for explaining a method for measuring the three-dimensional shape of a thick plate using a modified example of the automatic cutting device. 10 is a graph for explaining the effect of an embodiment in which the mounting angles of the distance sensor around two horizontal axes (ys _- axis) are calibrated by the calibration method of the present invention. This is an explanatory diagram of an embodiment in which the mounting angle of a distance sensor around the vertical axis ( _zs axis) is calibrated using the calibration method of the present invention, and is an explanatory diagram of a state in which the distance sensor is irradiating laser light onto a square as a calibration member placed on a surface plate. 14A and 14B are explanatory diagrams showing an example in which the mounting angle of a distance sensor around the vertical axis (z-axis, _s -axis) is calibrated by the calibration method of the present invention, in which (a) is an explanatory diagram showing three-dimensional shape measurement data obtained by measuring with a square along measurement path a shown in FIG. 13, and (b) is an explanatory diagram showing three-dimensional shape measurement data obtained by measuring with a square along measurement path b shown in FIG. 13A illustrates an example in which the mounting angle of a distance sensor around the vertical axis (zs _- axis) is calibrated using the calibration method of the present invention. FIG. 13A is a diagram superimposing coordinate transformation values obtained by coordinate-transforming three-dimensional shape measurement data obtained by measuring a square along measurement path a shown in FIG. 13 at a mounting angle of θz = 45° of the designed distance sensor on coordinate-transformed values obtained by coordinate-transforming three-dimensional shape measurement data obtained by measuring a square along measurement path b shown in FIG. 13 at a mounting angle of θz = 45° of the designed distance sensor. FIG. 13B is a diagram superimposing coordinate transformation values obtained by coordinate-transforming three-dimensional shape measurement data obtained by measuring a square along measurement path a shown in FIG. 13 at a mounting angle of 42.5°, which is obtained by changing the mounting angle of the distance sensor by Δθz = -2.5° from the mounting angle of the designed distance sensor by Δθz = -2.5° on coordinate-transformed values obtained by coordinate-transforming three-dimensional shape measurement data obtained by measuring a square along measurement path b shown in FIG. 13 at a mounting angle of 42.5°, which is obtained by changing the mounting angle of the distance sensor by Δθz = -2.5° from the mounting angle of the designed distance sensor by Δθz = 45°. 1A and 1B are diagrams for explaining methods of measuring the shape of a thick plate in a comparative example in which the shape of the thick plate after cutting is measured before the mounting angle of the distance sensor is calibrated in the automatic cutting device shown in FIG. 1, and in an example in which the shape of the thick plate after cutting is measured after the mounting angle of the distance sensor is calibrated in the automatic cutting device shown in FIG. 10 is a graph showing measurement results according to a comparative example. 10 is a graph showing measurement results according to an example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the materials, shapes, structures, arrangements, etc. of the components in the embodiments described below. Furthermore, the drawings are schematic. Therefore, it should be noted that the relationships and ratios between thicknesses and planar dimensions may differ from the actual ones, and the drawings may also contain portions where the relationships and ratios of dimensions differ from one another.
(Overall configuration of the automatic cutting device)
FIG. 1 shows a schematic configuration of an automatic cutting device as an automatic processing device according to one embodiment of the present invention.

The automatic cutting device 1 shown in Figure 1 is a gate-type cutting machine, and is equipped with a gate-type cart 3 that can run on wheels (not shown) on a pair of rails 2 laid to extend in the x direction (horizontal direction).
A tool 4 is provided on the side of the carriage 3, and is linearly movable in the y direction (a horizontal direction perpendicular to the x direction). A distance sensor 5 serving as a three-dimensional measuring device is attached to the tool 4 via an attachment angle adjustment mechanism 7 so as to be linearly movable in the z direction (vertical direction). The tool 4 is also provided with a cutting torch 6 serving as a processing device for cutting a thick plate S placed on a base 1a (see FIG. 4(a)) by thermal cutting such as gas cutting, laser cutting, or plasma cutting. The cutting torch 6 is attached to the tool 4 so as to be linearly movable in the z direction (vertical direction). While the distance sensor 5 and the cutting torch 6 are both attached to the tool 4 so as to be linearly movable, they do not need to move synchronously, and each can be independently linearly movable in the z direction.

The distance sensor 5, a three-dimensional shape measuring device, is a non-contact distance sensor that uses a light-section method to measure the distance to the object (thick plate S, surface plate 13, and calibration block 14, described below) by irradiating a line of laser light onto the object. As shown in Figures 3 to 7, the distance sensor 5 measures the two-dimensional shape of the object by irradiating the object with laser light 5c, capturing an image of the projected laser light 5c with a camera (not shown), and calculating the projection position of the laser light 5c on the image. The distance sensor 5 is then moved in the x and y directions by the carriage 3 and tool 4, and the three-dimensional shape of the object is measured by sequentially calculating the position coordinates of the tool 4 and the measurement data of the two-dimensional shape measured by the distance sensor 5. In other words, the distance sensor 5 measures the three-dimensional shape of the object by moving it in the x and y directions by the carriage 3 and tool 4. The three-dimensional shape measuring device attached to the carriage 3 is not limited to the light-section method distance sensor 5; other devices capable of measuring two-dimensional shape measurement data of the object may also be used. Other devices capable of measuring two-dimensional shape measurement data include, for example, sensors that use the TOF (Time of Flight) method as the measurement principle, such as two-dimensional LiDAR sensors.

The mounting angle adjustment mechanism 7 adjusts the mounting angle of the distance sensor 5 with respect to the tool 4. As shown in Figures 3(a), (b), and (c), the mounting direction of the distance sensor 5 is defined as the horizontal direction and the line direction of the laser light 5c (optical axis 5b) of the distance sensor 5 (the direction in which the laser light 5c spreads), which is defined as the horizontal first axis ( _xs- axis) direction. The horizontal direction and the direction perpendicular to the horizontal first axis (xs _- axis) are defined as the horizontal second axis ( _ys- axis) direction. The vertical axis (zs _- axis) direction is defined as the direction parallel to the optical axis 5b of the laser light 5c and perpendicular to the horizontal first axis (xs _- axis) direction and the horizontal second axis (ys _- axis) direction.
The mounting angle adjustment mechanism 7 is provided with a rotation shaft 7c (see FIG. 3(c)) that rotates the distance sensor 5 around one horizontal axis (xs _- axis) as an axis of mounting direction with respect to a coordinate system based on the laser light 5c of the distance sensor 5. Similarly, the mounting angle adjustment mechanism 7 is provided with a rotation shaft 7b (see FIG. 3(a)) that rotates the distance sensor 5 around two horizontal axes ( _ys- axis) as axes of mounting direction with respect to the coordinate system based on the laser light 5c of the distance sensor 5. Similarly, the mounting angle adjustment mechanism 7 is provided with a rotation shaft 7a (see FIG. 3(b)) that rotates the distance sensor 5 around a vertical axis (zs _- axis) as an axis of mounting direction with respect to the coordinate system based on the laser light 5c of the distance sensor 5.

That is, as shown in FIG. 3( a), the mounting angle adjustment mechanism 7 can rotate the distance sensor 5 around two horizontal axes (y _-s axes) perpendicular to the optical axis 5b of the distance sensor 5 using the rotation axis 7b. Also, as shown in FIG. 3( b), the mounting angle adjustment mechanism 7 can rotate the distance sensor 5 around a vertical axis (z _-s axis) parallel to the optical axis 5b of the distance sensor 5 using the rotation axis 7a. Furthermore, as shown in FIG. 3( c), the mounting angle adjustment mechanism 7 can rotate the distance sensor 5 around one horizontal axis (x- _s axis) parallel to the line direction (measurement width direction) of the laser light 5c of the distance sensor 5 using the rotation axis 7c. In this way, by varying the mounting angle of the distance sensor 5 using the rotation axes 7a to 7c, it is also possible to correct the actual mounting angle of the distance sensor 5 when calculating the mounting errors Δθx, Δθy, and Δθz of the distance sensor 5, which will be described later.

The automatic cutting device 1 also includes a control device 8. As shown in Figures 1 and 2, the control device 8 includes a control unit 9, a calibration device 10, and an output unit 11. The control device 8 is a computer system with a processing function, and executes the functions of the control unit 9, the calibration device 10, and the output unit 11 in accordance with instructions from a computer program installed in a storage device (not shown).
Here, the control unit 9 controls the operation of each component of the automatic cutting device 1 such as the carriage 3 , the tool 4 , the distance sensor 5 , and the cutting torch 6 .
Furthermore, the calibration device 10 calculates the installation errors of the three installation direction axes of the distance sensor 5 as a three-dimensional shape measuring device. Specifically, the calibration device 10 calculates the installation errors Δθx, Δθy, and Δθz about the horizontal axis (xs _- axis), the horizontal axis ( _{ys- axis} ), and the vertical axis ( _zs -axis) with respect to the horizontal axis (xs _- axis), the horizontal axis (ys-axis), and the vertical axis ( _zs- axis), respectively. When calculating these installation errors Δθx, Δθy, and Δθz, different calculation methods are used for the horizontal axis (xs _- axis), the horizontal axis (ys _- axis), and the vertical axis (zs _- axis).

As shown in Fig. 2, the calibration device 10 includes an installation error calculation unit 10a and an installation error output unit 10b. The installation error calculation unit 10a calculates installation errors Δθx, Δθy, and Δθz about the horizontal axis ( _{xs -} axis), the horizontal axis (ys _- axis), and the vertical axis (zs _- axis) using different calculation methods for each of the horizontal axis (xs _- axis), the horizontal axis (ys-axis), and the vertical axis (zs _- axis). The installation error output unit 10b outputs the installation errors Δθx, Δθy, and Δθz about the horizontal axis (xs _- axis), the horizontal axis (ys _- axis), and the vertical axis ( _zs- axis) calculated by the installation error calculation unit 10a, and displays this information on a display device such as a monitor.
Furthermore, the output unit 11 acquires the coordinate transformation value _ΣR (the position of the object to be measured in the xyz (movement) coordinate system in which the tool 4 is placed) that has been coordinate-transformed by the coordinate conversion unit 5a of the distance sensor 5, outputs the coordinate transformation value _ΣR , and displays the coordinate transformation value _ΣR as three-dimensional shape measurement data of the object to be measured on a display device such as a monitor.

The distance sensor 5 as the three-dimensional shape measuring device and the calibration device 10 constitute a three-dimensional shape measuring device 12 .
1, the distance sensor 5 is provided with a coordinate conversion unit 5a. The coordinate conversion unit 5a converts the measurement values (three-dimensional shape measurement data) in the sensor coordinate system measured by the distance sensor 5 into coordinate conversion values in the moving coordinate system of the tool 4 (the position of the object to be measured in the xyz (moving) coordinate system in which the tool 4 is located) using the following equation (1). The coordinate conversion unit 5a is a computer having an arithmetic processing function, and executes the coordinate conversion function in accordance with the instructions of a computer program installed in a storage device (not shown).

Σ _R =M _s +R _x・R _y・R _z・Σ _s …(1)
Here, _ΣR is the coordinate transformation value of the moving coordinate system of the tool 4 (the position of the workpiece in the xyz coordinate system in which the tool 4 is placed). _Ms is the position coordinate of the tool 4. _Rx is a coordinate transformation matrix about the single horizontal axis ( _xs axis) of the sensor coordinate system, _Ry is a coordinate transformation matrix about the second horizontal axis ( _ys axis) of the sensor coordinate system, and _Rz is a coordinate transformation matrix about the vertical axis ( _zs axis) of the sensor coordinate system. _Σs is the measurement value (three-dimensional shape measurement data) in the sensor coordinate system.
R _x , R _y , and R _z are respectively expressed by the following equations (2) to (4).

Note that θx is the mounting angle of the distance sensor 5 around the horizontal axis (xs _- axis) in the design, θy is the mounting angle of the distance sensor 5 around the horizontal axis ( _ys- axis) in the design, and θz is the mounting angle of the distance sensor 5 around the vertical axis (zs _- axis) in the design.
(Method for measuring three-dimensional shape of thick plate S as object to be measured)
Next, a method for measuring the three-dimensional shape of a thick plate S using the automatic cutting device 1 shown in FIG. 1 will be described.
Figure 4 explains a method for measuring the three-dimensional shape of a thick plate using an automatic cutting device, where (a) is a plan view of a thick plate placed on the base of the automatic cutting device, and (b) is a plan view explaining how the distance sensor moves in a zigzag pattern indicated by arrow A in a plan view from the state shown in (a) to measure the three-dimensional shape of the thick plate.

First, the thick plate S is placed on the base 1a between the pair of rails 2 of the automatic cutting device 1, as shown in FIG. 4(a).
Then, as shown in Figure 4 (b), the control unit 9 controls the carriage 3 and the tool 4 to move the distance sensor 5 in a zigzag pattern in a planar view, as indicated by arrow A, relative to the thick plate S to be measured, and the distance sensor 5 measures the three-dimensional shape of the thick plate S.
Then, the measurement value (three-dimensional shape measurement data) _Σs in the sensor coordinate system measured by the distance sensor 5 is converted into a coordinate transformation value in the moving coordinate system of the tool 4 (the position of the object to be measured in the xyz (moving) coordinate system in which the tool 4 is placed) by the coordinate conversion unit 5a using the above-mentioned equation (1).

The mounting angle θx of the distance sensor 5 around the horizontal axis (xs _- axis) in the design, the mounting angle θy of the distance sensor 5 around the horizontal axis (ys _- axis) in the design, and the mounting angle θz of the distance sensor 5 around the vertical axis (zs _- axis) in the design are input in advance by an operator to the coordinate conversion unit 5a from an input device (not shown).
Further, the position coordinates _Ms of the tool 4 in the x, y and z directions are obtained by the rotary encoder as the amount of rotation of the actuator in each direction, and the obtained information is input to the coordinate conversion unit 5a.
Then, the coordinate transformation value _ΣR of the moving coordinate system of the tool 4 (the position of the thick plate S in the xyz coordinate system where the tool 4 is located) transformed by the coordinate transformation unit 5a is sent to the output unit 11, which outputs the coordinate transformation value _ΣR and displays the coordinate transformation value _ΣR as three-dimensional shape measurement data of the object to be measured on a display device such as a monitor.
(Method for calibrating distance sensor installation error)
When the mounting angle of the distance sensor 5 relative to the tool 4 is different from the design mounting angles θx, θy, θz, and the coordinate transformation value _ΣR of the moving coordinate system of the tool 4 (the position of the object to be measured (thick plate S) in the xyz coordinate system in which the tool 4 is placed) is calculated using the above-mentioned equation (1), an error occurs in the measurement value. For this reason, it is necessary to calculate the mounting error Δθx of the mounting angle of the distance sensor 5 about the horizontal axis (xs _- axis), the mounting error Δθy of the mounting angle of the distance sensor 5 about the horizontal axis (ys _- axis), and the mounting error Δθz of the mounting angle of the distance sensor 5 about the vertical axis (zs _- axis), and to calibrate these errors.

In this embodiment, the calibration device 10 calculates installation errors Δθx, Δθy, and Δθz about the horizontal axis (xs _- axis), the horizontal axis (ys _- axis), and the vertical axis (zs _- axis) with respect to the horizontal axis (xs _- axis), the horizontal axis (ys _- axis), and the vertical axis ( _zs- axis) of the distance sensor 5. When calculating these installation errors Δθx, Δθy, and Δθz, different calculation methods are used for the horizontal axis (xs _- axis), the horizontal axis ( _ys- axis), and the vertical axis ( _zs- axis).
A. Calculation Method of Mounting Error Δθy of Distance Sensor 5 Around Two Horizontal Axes (ys _- Axes) A calculation method of the mounting error Δθy of the distance sensor 5 around two horizontal axes (ys _- axes) will be described with reference to FIGS. 5 and 8. FIG. 5 illustrates a calculation method of the mounting error of the distance sensor around two horizontal axes ( _ys - _axes ), where (a) is an explanatory diagram of a state in which the distance sensor is irradiating a laser beam onto the top surface of a surface plate serving as a calibration member, and (b) is an explanatory diagram of a state in which the distance sensor attached to a tool is irradiating a laser beam onto the top surface of a surface plate serving as a calibration member with a mounting error Δθy around two horizontal axes (ys-axes). FIG. 8 is a flowchart illustrating a process flow for calculating the mounting error of the distance sensor around two horizontal axes (ys _- axes) using a three-dimensional shape measuring device.

First, in step S1 shown in Fig. 8, an operator places a surface plate 13 serving as a calibration member having a leveled horizontal surface 13a (see Figs. 5(a) and 5(b)) on the base 1a of the automatic cutting device 1. The surface plate 13 is preferably portable and has an adjuster that can adjust the inclination of the surface plate 13.
Next, in step S2, the operator inputs a calculation command for the installation error Δθy around the two horizontal axes (y and _s axes) to the control unit 9, the calibration device 10, and the coordinate conversion unit 5a of the distance sensor 5, and also starts up the three-dimensional shape measuring device 12.
Next, in step S3, the distance sensor 5 as a three-dimensional shape measuring device measures the horizontal surface 13a of the surface plate 13 (surface plate measurement step). At this time, the control unit 9 controls the carriage 3 and the tool 4, and controls the position of the distance sensor 5.

Next, in step S4, the installation error calculation unit 10a of the calibration device 10 acquires shape data of the horizontal surface 13a of the surface plate 13 having the leveled horizontal surface 13a measured in step S3 by the distance sensor 5. Then, the installation error calculation unit 10a calculates the installation error Δθy about the two horizontal axes (ys _- axes) of the distance sensor 5 by approximating the acquired shape data of the horizontal surface 13a to a linear function to calculate the tilt of the horizontal surface 13a (calculation step).
Here, if an error occurs in the mounting angle of the distance sensor 5, the shape data of the horizontal surface 13a of the surface plate 13 measured by the distance sensor 5 is output with an inclination of the mounting error Δθy of the distance sensor 5, as shown in Fig. 5(b). The coordinate conversion unit 5a of the distance sensor 5 sends the shape data of the horizontal surface 13a measured by the distance sensor 5 to the mounting error calculation unit 10a of the calibration device 10 without performing coordinate conversion on the shape data of the horizontal surface 13a. The mounting error calculation unit 10a acquires the shape data of the horizontal surface 13a of the surface plate 13, approximates the acquired shape data of the horizontal surface 13a to a linear function, and calculates the inclination of the horizontal surface 13a, thereby calculating the mounting error Δθy of the distance sensor 5 about the two horizontal axes (y and _s axes).

Next, in step S5, the installation error output unit 10b of the calibration device 10 outputs the installation errors Δθy around the two horizontal axes ( _ys- axes) calculated by the installation error calculation unit 10a in step S4, and displays this information on a display device such as a monitor (installation error output step).
B. Calculation Method of Mounting Error Δθx of Distance Sensor 5 About One Horizontal Axis (xs _- axis) A calculation method of the mounting error Δθx of the distance sensor 5 about one horizontal axis (xs _- axis) will be described with reference to Fig. 6 and Fig. 9. Fig. 6 explains the calculation method of the mounting error of the distance sensor about the one horizontal axis ( _xs- axis), and includes (a) an explanatory diagram of a state in which the distance sensor irradiates laser light onto two horizontal surfaces of a calibration block as a calibration member placed on a surface plate, (b) an explanatory diagram of a state in which the distance sensor attached to a tool irradiates laser light onto the two horizontal surfaces of the calibration block in a state in which there is a mounting error Δθx about the one horizontal axis ( _{xs -} axis), and (c) a diagram showing the geometric relationship between a known height difference h between the two horizontal surfaces of the calibration block and a height difference herr between the two horizontal surfaces of the calibration block when the distance sensor attached to a tool irradiates laser light onto the two horizontal surfaces of the calibration block in a state in which there is a mounting error Δθx about the one horizontal axis (xs-axis). FIG. 9 is a flowchart for explaining the flow of a process for calculating the mounting error around one horizontal axis ( _xs axis) of the distance sensor using the three-dimensional shape measuring device.

First, in step S11 shown in FIG. 9 , an operator places a calibration block 14, which serves as a calibration member, on the surface plate 13 and has two horizontal surfaces 14 a, 14 b (see FIGS. 6( a), 6 (b), and 6 (c)) that are parallel to each other but have different heights and whose difference in leveled height h is known.
Next, in step S12, the operator inputs a calculation command for the installation error Δθx around a single horizontal axis ( _xs axis) to the control unit 9, the calibration device 10, and the coordinate conversion unit 5 a of the distance sensor 5, and also starts up the three-dimensional shape measuring device 12.
Next, in step S13, the distance sensor 5 serving as a three-dimensional shape measuring device measures the difference in height herr (see FIG. 6(c)) between the two horizontal surfaces 14a, 14b of the calibration block 14 (height difference measurement step). At this time, the control unit 9 controls the carriage 3 and the tool 4 to control the position of the distance sensor 5. Note that in the example shown in FIGS. 6(a), (b), and (c), the two horizontal surfaces 14a, 14b of the upper and middle levels of the two-level calibration block 14 are the measurement targets, but the two horizontal surfaces, the upper level horizontal surface 14a of the single-level calibration block 14 and the horizontal surface of the surface plate 13, may also be the measurement targets.

Next, in step S14, the installation error calculation unit 10a of the calibration device 10 acquires data on the height difference herr between the two horizontal surfaces 14a, 14b of the calibration block 14, the two horizontal surfaces 14a, 14b having a known leveled height difference h, measured by the distance sensor 5 in step S13. Then, the installation error calculation unit 10a calculates the installation error Δθx around the horizontal axis ( _xs axis) of the distance sensor 5 based on the known height difference h and the acquired height difference herr data (calculation step).
Here , the coordinate conversion unit 5a of the distance sensor 5 sends the data of the height difference herr measured by the distance sensor 5 to the installation error calculation unit 10a of the calibration device 10 without performing coordinate conversion on the data of the height difference herr.

Next, in step S15, the installation error output unit 10b of the calibration device 10 outputs the installation error Δθx about the horizontal axis ( _xs axis) calculated by the installation error calculation unit 10a in step S14, and displays this information on a display device such as a monitor (installation error output step).
C. Method for Calculating Mounting Error Δθz Around the Vertical Axis (zs _- axis) of Distance Sensor 5 A method for calculating the mounting error Δθz around the vertical axis (zs _- axis) of the distance sensor 5 will be described with reference to FIGS. 7A is a diagram illustrating a method for calculating the mounting error of a distance sensor about the vertical axis (zs _- axis), and shows (a) an explanatory diagram of a state in which the distance sensor is irradiating laser light onto two horizontal surfaces of a calibration block as a calibration member placed on a surface plate, (b) a plan view of the distance sensor attached to a tool with a mounting error Δθz about the vertical axis ( _zs -axis), (c) an explanatory diagram of the distance sensor attached to the tool measuring the calibration block along two different measurement paths a and b with a mounting error Δθz about the vertical axis (zs _- axis), and (d) a diagram illustrating a method for calculating the mounting angle at which the coordinate transformation values of the two moving coordinate systems coincide by superimposing the coordinate transformation values of the moving coordinate systems obtained by transforming two pieces of three-dimensional shape measurement data obtained by measuring the calibration block along the measurement paths a and b in two different directions using the method of (c). FIG. 10 is a flowchart illustrating a process for calculating the mounting error of a distance sensor about the vertical axis (zs _- axis) using a three-dimensional shape measuring device.

10, the operator places the calibration block 14, which has horizontal surfaces 14a and 14b and is square in plan view, as a calibration member, on the surface plate 13, as shown in FIG. 7A. The shape of the calibration block 14 is not limited to a three-dimensional shape having horizontal surfaces 14a and 14b and is square in plan view, but may be a cube, a cylinder, a rectangular parallelepiped, or the like.
Next, in step S112, the operator inputs a calculation command for the installation error Δθz around the vertical axis ( _zs axis) to the control unit 9, the calibration device 10, and the coordinate conversion unit 5a of the distance sensor 5, and starts the three-dimensional shape measuring device 12. The operator also inputs information on the installation angles θx, θy, θz of the designed distance sensor 5 and the minute angle dθz in the range of the installation angle θz±θ of the designed distance sensor 5 to be coordinate converted to the coordinate conversion unit 5a of the distance sensor 5.

Next, in step S113, the distance sensor 5 serving as a three-dimensional shape measuring device measures the calibration block 14 from two different, orthogonal measurement paths a and b, as shown in Fig. 7(c) (calibration block different direction measurement step). At this time, the control unit 9 controls the carriage 3 and tool 4 to control the position of the distance sensor 5. Note that the measurement directions of the measurement paths a and b are orthogonal to each other, but this is not necessarily the case.
Next, in step S114, the coordinate conversion unit 5a of the distance sensor 5 performs coordinate conversion on each of the two pieces of three-dimensional shape measurement data measured in step S113 (two pieces of data measured along measurement path a and measurement path b) using equation (1). During this coordinate conversion, for each of the two pieces of three-dimensional shape measurement data measured in step S113 (two pieces of data measured along measurement path a and measurement path b), coordinate conversion is performed using equation (1) for each small angle dθz within a range of ±θ from the design mounting angle θz. Then, coordinate conversion values Σr _,a and Σr _,b of the two moving coordinate systems are calculated (coordinate conversion process). In this case, the information on the design mounting angles θx, θy, θz of the distance sensor 5 and the small angle dθz within a range of ±θ of the design mounting angle θz of the distance sensor 5 to be coordinate converted, which are introduced into equation (1), are the information input to the coordinate conversion unit 5a in step S112. Further, the position coordinates _Ms of the tool 4 are obtained by acquiring the rotation amounts of the actuator in the x-, y-, and z-directions using a rotary encoder, and the acquired information is input to the coordinate conversion unit 5a.

For each of the two pieces of three-dimensional shape measurement data measured in step S113 (two pieces of data measured along measurement path a and measurement path b), coordinate conversion is performed using equation (1) with the design mounting angle θz, and coordinate conversion values Σr _,a and Σr _,b in the moving coordinate system are calculated as shown in Fig. 7(d). If there is an error in the mounting angle (θz) of the distance sensor 5, the measured shape of the calibration block 14 will be distorted as shown in figures 15a and 15b in Fig. 7(d). The distortion of the shape will differ depending on the measurement path.
Therefore, in this embodiment, in step S114, the coordinate conversion unit 5a of the distance sensor 5 converts the coordinates of each of the two three-dimensional shape measurement data measured in step S113 for each small angle dθz in the range of ±θ from the design mounting angle θz using equation (1) to calculate coordinate transformation values Σr _,a and Σr _,b of the two moving coordinate systems. Then, in the next step S115, the calibration device 10 calculates the mounting angle at which the coordinate transformation values Σr _,a and Σr _,b of the two moving coordinate systems match, and calculates the mounting error Δθz around the vertical axis ( _zs axis) of the distance sensor 5.

Next, in step S115, the installation error calculation unit 10a of the calibration device 10 acquires coordinate transformation values Σr _,a ((the figure indicated by reference numeral 15a in FIG. 7(d)) and Σr _{,b (the figure indicated by reference numeral 15b in FIG. 7(d)) of the two moving coordinate systems that were subjected to coordinate transformation by the coordinate transformation unit 5a of the distance sensor 5} in step S114. Then, the installation error calculation unit 10a superimposes the acquired coordinate transformation values Σr _,a and Σr _,b of the two moving coordinate systems to calculate the installation angle at which the coordinate transformation values Σr _,a and Σr _,b of the two moving coordinate systems coincide. In this way, the installation error Δθz around the vertical axis ( _zs- axis) of the distance sensor 5 is calculated (calculation step). In FIG. 7(d), the coinciding coordinate transformation values Σr _,a and _Σr,b are the figures indicated by reference numerals 16a and 16b, respectively.

Here, the coordinate transformation values Σr _,a and Σr _,b of the two moving coordinate systems being the same means that the edge portions of the three-dimensional point cloud data of the coordinate transformation value Σr _,a of the moving coordinate system overlap with the edge portions of the three-dimensional point cloud data of the coordinate transformation value Σr _,b of the moving coordinate system. Here, "overlapping" means that the distance between the edge portions is 1.0 mm or less.
For example, if the designed mounting angle θz of the distance sensor 5 is 45° and coordinate transformation is performed in increments of 0.1° within a range of ±3°, the coordinate transformation values Σr _,a and Σr _,b of the two moving coordinate systems are calculated in sequence as 42.0°, 42.1°, 42.2°, ..., 47.9°, and 48.0°. Then, the coordinate transformation values Σr _,a and Σr _,b of the two moving coordinate systems are superimposed, and the angle when the edge portions of the three-dimensional point cloud data of _Σr,a and Σr _,b overlap becomes the mounting angle θz±the mounting error Δθz.

Next, in step S116, the installation error output unit 10b of the calibration device 10 outputs the installation error Δθz about the vertical axis (zs _- axis) calculated by the installation error calculation unit 10a in step S115, and displays this information on a display device such as a monitor (installation error output step).
D. Calibration of Mounting Angle of Distance Sensor 5 In this embodiment, after the mounting errors Δθx, Δθy, and Δθz are calculated by the above-described methods A to C, the mounting angle of the distance sensor 5 is calibrated based on the calculated mounting errors Δθx, Δθy, and Δθz.

As a method for calibrating the mounting angle of the distance sensor 5, for example, there is a method of directly correcting the mounting angle of the distance sensor 5 by the calculated mounting errors Δθx, Δθy, Δθz. There is also a method of correcting the coordinate transformation sequences R x , R y , R z when transforming the measurement value Σ _s in the sensor coordinate system into the coordinate transformation value _{Σ R} in the movement coordinate system of the tool 4 (the position of the object to be measured in the xyz coordinate system in which the tool ₄ is placed) using the above-mentioned equation ( ₁ ).
In the former case of directly correcting the mounting angle of the distance sensor 5, the mounting angle of the distance sensor 5 is corrected by the calculated mounting errors Δθx, Δθy, Δθz, and then the three-dimensional shape of the object to be measured is measured using the distance sensor 5.

On the other hand, when correcting the latter coordinate transformation sequence _Rx , _Ry , _Rz , the three-dimensional shape of the object to be measured is measured using the distance sensor 5 without correcting the mounting angle of the distance sensor 5. Then, when the coordinate conversion unit 5a converts the measurement value _Σs in the sensor coordinate system, the values of the coordinate transformation sequence _Rx , _Ry , _Rz in equation (1) are corrected taking into account the calculated mounting errors Δθx, Δθy, Δθz. Specifically, the calculated mounting errors Δθx, Δθy, Δθz are added to the design mounting angles θx, θy, θz in equations (2) to (4) to calculate the corrected coordinate transformation sequence _Rx , _Ry , _Rz using the following equations (6) to (8). Then, these corrected coordinate transformation sequences R _x , R _y , R _z are multiplied by the measurement value Σ _s in the sensor coordinate system, and the position coordinate of the tool 4 is added to obtain the coordinate transformation value Σ _R in the moving coordinate system of the tool 4 (the position of the object to be measured in the xyz coordinate system in which the tool 4 is placed) using equation (1).

(Method for cutting a thick plate using the automatic cutting device 1)
When cutting a thick plate S using the automatic cutting device 1 according to this embodiment, the mounting errors Δθx, Δθy, and Δθz of the distance sensor 5 are calculated in advance. That is, before placing the thick plate S on the base 1a of the automatic cutting device 1, the mounting errors Δθx, Δθy, and Δθz of the distance sensor 5 are calculated using the methods A to C described above. Then, when calibrating the mounting angle of the distance sensor 5 by directly correcting the mounting angle of the distance sensor 5 by the calculated mounting errors Δθx, Δθy, and Δθz, the mounting angle of the distance sensor 5 is corrected at this point.

Next, the thick plate S before cutting is placed on the pedestal 1a of the automatic cutting device 1, and the three-dimensional shape of the thick plate S is measured using the distance sensor 5. Then, the measurement value _Σs in the sensor coordinate system measured by the distance sensor 5 is coordinate-converted in the coordinate conversion unit 5a into a coordinate transformation value _ΣR in the movement coordinate system of the tool 4 (the position of the thick plate S in the xyz coordinate system in which the tool 4 is arranged) using equation (1). If the coordinate transformation sequence _Rx , _Ry , _Rz is corrected as a method of calibrating the mounting angle of the distance sensor 5, the values of the coordinate transformation sequence Rx, Ry, Rz in equation (1) are corrected at this point when the measurement value _Σs in the sensor coordinate system is coordinate-converted by the coordinate conversion unit 5a, taking into account the calculated mounting errors _Δθx , _Δθy , _Δθz . Then, these corrected coordinate transformation sequences _Rx , _Ry , _Rz are multiplied by the measurement value _Σs in the sensor coordinate system (three-dimensional shape measurement data measured by the distance sensor 5), and the position coordinate of the tool 4 is added to obtain the coordinate transformation value _ΣR in the moving coordinate system of the tool 4 (the position of the thick plate S in the xyz coordinate system in which the tool 4 is located) using equation (1).

Then, the cutting position of the thick plate S is determined from the coordinate transformation value Σ _R of the movement coordinate system of the tool 4 (the position of the thick plate S in the xyz coordinate system in which the tool 4 is placed), and the automatic cutting device 1 aligns the tool 4 along the cutting position and cuts the thick plate S with the cutting torch 6. In this way, a thick plate product having the specified product dimensions is cut out.
The three-dimensional shape of the cut thick plate product is then measured again using the distance sensor 5, and the measurement value _Σs in the sensor coordinate system measured by the distance sensor 5 is coordinate-converted in the coordinate conversion unit 5a into the coordinate transformation value _ΣR in the moving coordinate system of the tool 4 using equation (1), to confirm whether the dimensions of the cut thick plate product are the specified dimensions. If the coordinate transformation sequence _Rx , _Ry , _Rz is corrected as a method of calibrating the mounting angle of the distance sensor 5, the values of the coordinate transformation sequence _Rx , _Ry , _Rz in equation (1) are corrected at this point when the measurement value _Σs in the sensor coordinate system is coordinate-converted by the coordinate conversion unit 5a, taking into account the calculated mounting errors Δθx, Δθy, Δθz. Then, these corrected coordinate transformation sequences _Rx , _Ry , _Rz are multiplied by the measurement value _Σs in the sensor coordinate system, and added with the position coordinates of the tool 4 to obtain _ΣR : the moving coordinate system (the position of the thick plate S in the xyz coordinate system where the tool 4 is located) using equation (1).

As described above, the calibration method for a three-dimensional shape measuring device according to this embodiment includes a calculation step (steps S14, S4, and S115) in which the calibration device 10 calculates installation errors about three installation direction axes (the first horizontal axis (xs _- axis), the second horizontal axis (ys _- axis), and the vertical axis (zs _- axis)) of the distance sensor 5 serving as the three-dimensional shape measuring device. In this calculation step, different calculation methods are used for the installation direction axes (the first horizontal axis (xs _- axis), the second horizontal axis (ys _- axis), and the vertical axis ( _zs- axis)) to calculate the installation errors about the three installation direction axes.
This makes it possible to calculate the installation error of the distance sensor 5 as a three-dimensional shape measuring device using an optimal calculation method corresponding to each installation direction axis, and to calculate the installation error around the three installation direction axes of the distance sensor 5 (the first horizontal axis (xs _- axis), the second horizontal axis (ys _- axis), and the vertical axis (zs _- axis)) with high precision.

Furthermore, since only the mounting error around one axis in the mounting direction is calculated using one calculation method, the device configuration and calculation process for each calculation method can be simplified.
Furthermore, according to the calibration method for a three-dimensional shape measuring device of the embodiment, the calibration device 10 performs the following processing in a calculation step (step S14) of calculating an installation error about a single horizontal axis (xs _- axis) of the distance sensor 5 serving as a three-dimensional shape measuring device. That is, the calibration device 10 acquires data on the height difference herr between the two horizontal surfaces 14a, 14b of the calibration block 14 serving as a calibration member having two leveled horizontal surfaces 14a, 14b with a known height difference h, measured by the distance sensor 5 (measured in step S13). Then, the calibration device 10 calculates the installation error Δθx about the single horizontal axis of the distance sensor 5 using the above-mentioned equation (5) based on the known height difference h and the acquired height difference herr data (step S14).

This makes it possible to calculate the mounting error Δθx of the distance sensor 5 around the horizontal axis with high accuracy using a simple method.
Furthermore, according to the method for calibrating a three-dimensional shape measuring device of this embodiment, the calibration device 10 performs the following processing in a calculation step (step S4) for calculating the installation errors about two horizontal axes (y-axis _{and s-} axis) of the distance sensor 5 serving as the three-dimensional shape measuring device. That is, the calibration device 10 acquires shape data of the horizontal surface 13a of the surface plate 13 serving as a calibration member having the leveled horizontal surface 13a measured by the distance sensor 5 (measured in step S3). Then, the calibration device 10 calculates the installation error Δθy about the two horizontal axes of the distance sensor 5 by approximating the acquired shape data of the horizontal surface 13a to a linear function and calculating the tilt of the horizontal surface 13a (step S4).

This makes it possible to calculate the mounting error Δθy around the two horizontal axes of the distance sensor 5 with high accuracy using a simple method.
Furthermore, according to the method for calibrating a three-dimensional shape measuring device of this embodiment, the calibration device 10 performs the following processing in a calculation step (step S115) for calculating an installation error about the vertical axis (zs _- axis) of the distance sensor 5 serving as the three-dimensional shape measuring device. That is, for each of two pieces of three-dimensional shape measurement data (measurement values in the sensor coordinate system) _Σs obtained by the distance sensor 5 measuring the calibration block 14 serving as the calibration member from two different measurement paths a and b, the calibration device 10 acquires two coordinate transformation values Σr _,a and Σr _,b by performing coordinate transformation for each small angle dθz within a range of ±θ from the designed installation angle θz. Then, the calibration device 10 superimposes the two acquired coordinate transformation values Σr _,a and Σr _,b to calculate the installation angle at which the two coordinate transformation values _Σr,a and Σr _,b coincide, thereby calculating an installation error Δθz about the vertical axis of the distance sensor 5 (step S115).

This makes it possible to calculate the mounting error Δθz of the distance sensor 5 around the vertical axis with high accuracy using a simple method.
Furthermore, the three-dimensional shape measuring apparatus 12 according to this embodiment includes a distance sensor 5 as a three-dimensional shape measuring device for measuring the three-dimensional shape of an object to be measured, and a calibration device 10. The calibration device 10 calculates installation errors Δθx, Δθy, and Δθz about the three installation direction axes (the first horizontal axis ( _{xs -} axis), the second horizontal axis ( _{ys- axis} ), and the vertical axis ( _{zs -} axis)) of the distance sensor 5. When calculating these installation errors Δθx, Δθy, and Δθz, different calculation methods are used for the installation direction axes (the first horizontal axis (xs _- axis), the second horizontal axis (ys _- axis), and the vertical axis ( _zs- axis)).

This allows the calibration device 10 to calculate the installation error of the distance sensor 5 as a three-dimensional shape measuring device using the optimum calculation method corresponding to each installation direction axis. Therefore, the installation error around the three installation direction axes (the first horizontal axis (xs _- axis), the second horizontal axis (ys _- axis), and the vertical axis (zs _- axis)) of the distance sensor 5 can be calculated with high accuracy.
Furthermore, the automatic cutting device 1 as an automatic processing device according to this embodiment includes the above-described three-dimensional shape measuring device 12 and a cutting torch 6 as a processing device that processes the thick plate S as the object to be measured. The distance sensor 5 as a three-dimensional shape measuring device measures the three-dimensional shape of the thick plate S at least one of before and after processing by the cutting torch 6.

This allows the calibration device 10 of the three-dimensional shape measuring device 12 to accurately calculate the installation error of the distance sensor 5 as a three-dimensional shape measuring device using the optimal calculation method corresponding to each installation direction axis, thereby enabling the three-dimensional shape of at least one of the thick plates S before and after processing by the cutting torch 6 to be measured with high accuracy.
Although the embodiment of the present invention has been described above, the present invention is not limited to this and various modifications and improvements can be made.
For example, it is not necessary to calculate the installation error of the distance sensor 5 for all three axes, namely, the horizontal axis (xs _- axis), the horizontal axis (ys _- axis), and the vertical axis ( _zs- axis), which are the installation direction axes of the distance sensor 5, and it is sufficient to calculate the error only for the necessary axes. For example, when a cutting torch 6 installed in the vertical direction (z-axis) is moved horizontally (y-axis) to cut a thick plate S, it is not necessary to consider the installation error Δθx around the horizontal axis ( _xs -axis) of the distance sensor 5. Therefore, it is sufficient to calibrate only the installation errors around the two axes, the horizontal axis (ys _- axis) and the vertical axis (zs _- axis).

The distance sensor 5 has three mounting axes: one horizontal axis (xs _- axis), two horizontal axes (ys _- axis), and a vertical axis (zs _- axis). However, the number of mounting axes is not limited to three, and any number of axes may be used.
In addition, although the case where the distance sensor 5 as a three-dimensional measuring device is attached to the automatic cutting device 1 and a thick plate S as a measurement object is cut has been described, the three-dimensional shape measuring device 12 can also be installed independently. The three-dimensional shape measuring device 12 can also be attached to various automatic processing devices for measurement objects other than the automatic cutting device 1. Furthermore, the measurement object is not limited to the thick plate S, and the three-dimensional shape measuring device 12 can be adapted to measure the three-dimensional shapes of various objects.

Furthermore, the automatic cutting device 1 is not limited to a gate-type cutting machine as long as it is configured to be able to move the cutting torch 6 and the distance sensor 5 relative to the object to be measured.
Furthermore, the distance sensor 5 as a three-dimensional shape measuring device measures the three-dimensional shape of the thick plate S as the object to be measured both before and after processing by the cutting torch 6 as a processing device. However, this is not limited to this case, and it is sufficient if the three-dimensional shape of the thick plate S is measured at least either before or after processing.
Furthermore, when measuring the three-dimensional shape of a thick plate S using the automatic cutting device 1, as shown in Figure 11, multiple distance sensors 5 may be installed in the width direction of the gate-shaped cart 3, and each of the multiple distance sensors 5 may be scanned only in the direction of arrow B (x direction) to measure the three-dimensional shape of the thick plate S.

(1) An example in which the mounting angle of a distance sensor around two horizontal axes ( _ys- axes) is calibrated by the calibration method of the present invention will be described with reference to Fig. 12. Fig. 12 is a graph for explaining the effect of an example in which the mounting angle of a distance sensor around two horizontal axes ( _ys- axes) is calibrated by the calibration method of the present invention.
In the method for calculating the installation error Δθy of the distance sensor 5 around the two horizontal axes (ys _- axes) shown in A described above, the distance sensor 5 measures the horizontal surface 13a of the leveled surface plate 13, and the calibration device 10 acquires the shape data of the horizontal surface 13a measured by the distance sensor 5. Then, the calibration device 10 approximates the acquired shape data of the horizontal surface 13a to a linear function to calculate the tilt of the horizontal surface 13a. As a result, the tilt of the horizontal surface 13a was found to be 0.51°. As a result, the calibration device 10 calculated the installation error Δθy of the distance sensor 5 around the two horizontal axes (ys _- axes) to be 0.51°.
Then, the worker corrected the mounting angle of the distance sensor 5 around the two horizontal axes (y and _s axes) by 0.51° and measured the horizontal surface 13a of the surface plate 13. As a result, as shown in Figure 12, the inclination of the horizontal surface 13a of the surface plate 13 was close to 0°.

(2) An embodiment in which the mounting angle of a distance sensor around the vertical axis (zs _- axis) is calibrated using the calibration method of the present invention will be described with reference to FIGS. 13 to 15 . FIG. 13 illustrates an embodiment in which the mounting angle of a distance sensor around the vertical axis (zs _- axis) is calibrated using the calibration method of the present invention, and is an explanatory diagram of a state in which the distance sensor is irradiating a laser beam onto a square as a calibration member placed on a surface plate. FIG. 14( a) is an explanatory diagram showing three-dimensional shape measurement data obtained by measuring a square using the measurement path a shown in FIG. 13 . FIG. 14( b) is an explanatory diagram showing three-dimensional shape measurement data obtained by measuring a square using the measurement path b shown in FIG. 13 . FIG. 15( a) is a diagram superimposing coordinate transformation values obtained by converting the three-dimensional shape measurement data obtained by measuring a square using the measurement path a shown in FIG. 13 at a designed mounting angle of the distance sensor θz = 45° and coordinate transformation values obtained by converting the three-dimensional shape measurement data obtained by measuring a square using the measurement path b shown in FIG. 13 at a designed mounting angle of the distance sensor θz = 45°. Figure 15(b) is a diagram superimposing coordinate copyright values obtained by coordinate transformation of three-dimensional shape measurement data measured with a square along measurement path a shown in Figure 13 at an installation angle of 42.5°, which is a change of Δθz = -2.5° from the design distance sensor installation angle θz = 45°, and coordinate transformation values obtained by coordinate transformation of three-dimensional shape measurement data measured with a square along measurement path b shown in Figure 13 at an installation angle of 42.5°, which is a change of Δθz = -2.5° from the design distance sensor installation angle θz = 45°.

In the method of calculating the installation error Δθz around the vertical axis ( _zs axis) of the distance sensor 5 shown in C described above, the distance sensor 5 measured the square T from two different, perpendicular measurement paths a and b as shown in Fig. 13. As a result, the measurement value (three-dimensional shape measurement data) Σa in the sensor coordinate system when the square T was measured along measurement path a shown in Fig. 13 was as shown in Fig. 14(a), and the measurement value (three-dimensional shape measurement data) Σb in the sensor coordinate system when the square T was measured along measurement path b shown in Fig. 13 was as shown in Fig. 14(b).
Then, the coordinate conversion unit 5a of the distance sensor 5 calculated coordinate conversion values Σr,a and Σr,b in the moving coordinate system by converting the measurement value (three-dimensional shape measurement data) Σa and the measurement value (three-dimensional shape measurement data) _Σb of the sensor coordinate system measured by the distance sensor 5 using equation (1) with the designed mounting angle θz of the distance sensor set to ₄₅ °. At this time, the designed mounting angle θx of the distance sensor was set to 0°, and θy was set to 0°.

The calibration device 10 then acquired the calculated coordinate transformation values Σr _,a and Σr _,b and superimposed them as shown in Fig. 15(a). As a result, there was an error of 4.07 mm between the coordinate transformation values Σr _,a and Σr _,b .
Furthermore, the coordinate conversion unit 5a of the distance sensor 5 calculated coordinate conversion values Σr,a', Σr,b' in the moving coordinate system by converting the sensor coordinate system measurement value (three-dimensional shape measurement data) Σa and the sensor coordinate system measurement value (three-dimensional shape measurement data) Σb measured by the distance sensor 5 using equation (1) where the design distance sensor mounting angle θz: ₄₅ ° - mounting error Δθz: 2.5° _{= 42.5} °. In this case, the design distance sensor mounting angle θx remains 0°, and θy remains 0°.
Then, the calibration device 10 acquired both coordinate transformation values Σr _,a ' and Σr _,b ' and overlaid them as shown in FIG. 15(b). As a result, the error between both coordinate transformation values Σr _,a ' and Σr _,b ' was 0.37 mm, which was almost the same. As a result, the calibration device 10 calculated the installation error Δθz around the vertical axis ( _zs axis) of the distance sensor 5 to be 2.5°.
Then, the mounting angle of the distance sensor 5 around the vertical axis ( _zs axis) was corrected by 2.5°.

(3) Next, with reference to Figures 16 to 18, a comparative example will be described in which the shape of the thick plate S after cutting is measured before the mounting angle of the distance sensor 5 is calibrated in the automatic cutting device 1 shown in Figure 1, and an example will be described in which the shape of the thick plate S after cutting is measured after the mounting angle of the distance sensor 5 is calibrated in the automatic cutting device 1 shown in Figure 1.
Fig. 16 is a diagram for explaining a method for measuring the shape of a thick plate in a comparative example in which the shape of the thick plate after cutting is measured in a state before the mounting angle of the distance sensor 5 is calibrated in the automatic cutting device 1 shown in Fig. 1, and an example in which the shape of the thick plate after cutting is measured in a state after the mounting angle of the distance sensor 5 is calibrated in the automatic cutting device 1 shown in Fig. 1. Fig. 17 is a graph showing the measurement results in the comparative example. Fig. 18 is a graph showing the measurement results in the example.
In the comparative example, in Fig. 16, before the mounting angle of the distance sensor 5 was calibrated, the shape of the thick plate S after cutting was measured along the direction indicated by the arrow C, and the longitudinal dimension lx and width dimension ly of the thick plate S were determined. Then, the shape of the thick plate S after cutting was measured manually using a tape measure, and the longitudinal dimension Lx and width dimension Ly of the thick plate S were determined.

The difference between Lx and Ly measured manually using a tape measure and lx and ly measured using the method of the comparative example was taken as the measurement errors dx and dy.
dx = Lx - lx
dy = Ly - ly
The results of the measurement errors dx and dy are shown in FIG.

As shown in FIG. 17 and Table 1, the measurement errors dx and dy between Lx and Ly obtained by manual measurement using a tape measure and lx and ly obtained by measurement using the method of the comparative example were very large, with the maximum measurement error dx being approximately 3 mm and the maximum measurement error dy being approximately 7.5 mm.
In contrast to this, in the example shown in Figure 16, after the installation angle of the distance sensor 5 was calibrated, the shape of the thick plate S after cutting was measured along the direction shown by arrow C, and the longitudinal dimension lx and width dimension ly of the thick plate S were obtained. Then, the shape of the thick plate S after cutting was measured manually using a tape measure, and the longitudinal dimension Lx and width dimension Ly of the thick plate S were obtained.
The difference between Lx and Ly measured manually using a tape measure and lx and ly measured by the method of the embodiment was taken as the measurement errors dx and dy.
dx = Lx - lx
dy = Ly - ly
The results of the measurement errors dx and dy are shown in FIG.

As shown in Figure 18 and Table 2, the measurement errors dx and dy between Lx and Ly measured manually using a tape measure and lx and ly measured using the method of the embodiment were approximately 0.86 mm at maximum and approximately 0.96 mm at maximum, confirming that the measurement errors were reduced compared to the comparative example.

1 Automatic cutting device (automatic processing device)
1a Base 2 Rail 3 Cart 4 Tool 5 Distance sensor (3D shape measuring device)
5a Coordinate conversion unit 5b Optical axis 5c Laser light 6 Cutting torch (processing equipment)
7 Mounting angle adjustment mechanism 7a Rotation axis 7b Rotation axis 7c Rotation axis 8 Control device 9 Control unit 10 Calibration device 10a Mounting error calculation unit 10b Mounting error output unit 11 Output unit 12 Three-dimensional shape measuring device 13 Surface plate (calibration member)
13a Horizontal surface 14 Calibration block (calibration member)
14a Horizontal surface 14b Horizontal surface S Thick plate (object to be measured)

Claims (4)

1. A calibration method for a three-dimensional shape measuring device for calibrating an installation error of the three-dimensional shape measuring device for measuring the three-dimensional shape of an object to be measured, comprising:
a calculation step of calculating, by a calibration device, an installation error around each of a plurality of installation direction axes of the three-dimensional shape measuring device using a different calculation method for each of the installation direction axes ;
the three-dimensional shape measuring device is a distance sensor that irradiates a line-shaped laser beam onto the object to be measured and measures the distance to the object to be measured, and the multiple mounting direction axes are three axes: a horizontal axis that is horizontal and in the line direction of the laser beam, two horizontal axes that are horizontal and perpendicular to the horizontal axis, and a vertical axis that is parallel to the laser beam and perpendicular to the horizontal axis and the two horizontal axes;
In the calculation step of calculating the installation error of the three-dimensional shape measuring device about the vertical axis by the calibration device, the calibration device acquires two coordinate transformation values by performing coordinate transformation for each small angle dθz in a range of ±θ from the design installation angle θz for each of two three-dimensional shape measurement data obtained by the three-dimensional shape measuring device measuring a calibration member from two different measurement paths, and then calculates the installation error Δθz about the vertical axis of the three-dimensional shape measuring device by superimposing the two coordinate transformation values acquired by the calibration device . 2. The calibration method for a three-dimensional shape measuring instrument according to claim 1, wherein in the calculation step of calculating the installation errors of the three-dimensional shape measuring instrument about the two horizontal axes by the calibration device, the calibration device acquires shape data of the horizontal plane of a calibration member having a leveled horizontal surface measured by the three-dimensional shape measuring instrument, and calculates the installation error Δθy of the three-dimensional shape measuring instrument about the two horizontal axes by approximating the shape data of the horizontal plane acquired by the calibration device to a linear function to calculate the tilt of the horizontal plane. a three-dimensional shape measuring device for measuring the three-dimensional shape of an object to be measured;
a calibration device that calculates an installation error around each of a plurality of installation direction axes of the three-dimensional shape measuring device using a different calculation method for each of the installation direction axes,
the three-dimensional shape measuring device is a distance sensor that irradiates a line-shaped laser beam onto the object to be measured and measures the distance to the object to be measured, and the multiple mounting direction axes are three axes: a horizontal axis that is horizontal and in the line direction of the laser beam, two horizontal axes that are horizontal and perpendicular to the horizontal axis, and a vertical axis that is parallel to the laser beam and perpendicular to the horizontal axis and the two horizontal axes;
a calibration device for calculating an installation error about the vertical axis of the three-dimensional shape measuring instrument by the calibration device, the calibration device acquiring two coordinate transformation values by performing coordinate transformation for each small angle dθz in a range of ±θ from the design installation angle θz for each of two pieces of three-dimensional shape measurement data obtained by the three-dimensional shape measuring instrument measuring a calibration member from two different measurement paths, and then superimposing the two coordinate transformation values acquired by the calibration device to calculate an installation angle at which the two coordinate transformation values coincide, thereby calculating an installation error Δθz about the vertical axis of the three-dimensional shape measuring instrument . a three-dimensional shape measuring device including: a three-dimensional shape measuring device that measures the three-dimensional shape of an object to be measured; and a calibration device that calculates installation errors about a plurality of installation direction axes of the three-dimensional shape measuring device using different calculation methods for each of the installation direction axes;
a processing device for processing the object to be measured,
the three-dimensional shape measuring device measures the three-dimensional shape of the object to be measured at least one of before and after processing by the processing device ,
the three-dimensional shape measuring device is a distance sensor that irradiates a line-shaped laser beam onto the object to be measured and measures the distance to the object to be measured, and the multiple mounting direction axes are three axes: a horizontal axis that is horizontal and in the line direction of the laser beam, two horizontal axes that are horizontal and perpendicular to the horizontal axis, and a vertical axis that is parallel to the laser beam and perpendicular to the horizontal axis and the two horizontal axes;
the calibration device acquires two coordinate transformation values obtained by coordinate transformation for each small angle dθz in a range of ±θ from the design mounting angle θz for each of two pieces of three-dimensional shape measurement data obtained by the three-dimensional shape measuring device measuring a calibration member from two different measurement paths, and then superimposes the two coordinate transformation values acquired by the calibration device to calculate the mounting angle at which the two coordinate transformation values match, thereby calculating the mounting error Δθz of the three-dimensional shape measuring device about the vertical axis .