Method for measuring shape, apparatus for measuring shape, and method for manufacturing a product

Abstract

To measure the shape of the material being measured with greater accuracy. [Solution] When measuring the shape of the material to be measured 11 using a shape measuring sensor 2 that moves above the material to be measured 11, the shape measuring sensor 2 outputs a pulse signal each time it moves a predetermined unit distance, and the shape measuring sensor 2 performs a measurement in synchronization with the output of the pulse signal, thereby acquiring shape data of the material to be measured 11 by the shape measuring sensor 2, and the position information of the acquired shape data in the direction of movement is determined based on the product of the number of pulse signal outputs and the unit distance.

Description

Technical Field

[0001] The present invention relates to a technique for measuring the shape of a measurement target material such as a metal plate, and a manufacturing method of a product having such a technique. The present invention is a technique suitable for easily and more accurately measuring the three-dimensional shape of the measurement target material. The shape of the measurement target material is, for example, an outer dimension (outer peripheral contour shape), flatness of the upper surface, and the like.

Background Art

[0002] For example, in the thick plate refining process of a steel mill, an operation of cutting a rolled material rolled in a rolling process into a specified dimension is carried out. At this time, shape measurement of the measurement target material is performed before and after cutting. The shape measurement before cutting is performed, for example, for the following purposes. That is, shape measurement is performed to obtain the placement position of the rolled material (measurement target material) of the processing object during gas cutting or the like. In addition, shape measurement is performed to determine whether the dimensions of the target product can be obtained from the rolled material. Further, the shape measurement after cutting is performed, for example, to confirm whether the target processing has been performed.

[0003] Here, as a method for cutting the rolled material, methods such as gas cutting, laser cutting, or plasma cutting are adopted. The cutting operation is usually performed by a gantry numerical control cutting machine or a gantry self-propelled cutting machine. Therefore, the cutting operation has advanced automation. On the other hand, the dimensional measurement and plate flatness measurement of the rolled material (thick plate) before and after cutting are still mostly manual operations.

[0004] Such shape measurement operations of the rolled material before and after cutting are conventionally heavy labor operations. Further, when this operation is performed by an operator, there is a risk of falling due to a poor working scaffold. Further, when this operation is performed by an operator, it becomes an entry operation into the manufacturing line, and thus there is a risk of accidents such as collisions and narrow pressure disasters due to interference with the cutting processing apparatus, so it is necessary to perform the operation carefully.

[0005] Furthermore, manual measurements present challenges such as individual differences and human error in measurement accuracy, as well as the inability to collect a sufficient number of measurement points.

[0006] In response to this, in recent years, non-contact shape measurement methods using optical means have been employed as a method for measuring the dimensions of materials to be measured without human intervention. Such methods are described, for example, in Patent Documents 1 and 2.

[0007] The method described in Patent Document 1 employs a shape measurement sensor using the light section method. This light section method measures the shape of a material by irradiating it with laser light from above and capturing the irradiated laser light with a camera from a different angle. Patent Document 1 describes mounting multiple such shape measurement sensors in a row on a gantry frame. Furthermore, Patent Document 1 discloses measuring the three-dimensional shape of a material by measuring the shape of the material from above while moving the gantry frame horizontally in one direction.

[0008] The method described in Patent Document 2 involves mounting a non-contact distance sensor as a shape measuring sensor on a gantry-type cutting machine. The document discloses that the external dimensions of the material to be cut are calculated from the sensing data of the distance sensor while the cutting head (gantry-type frame) is moving. The sensing data measured is distance data from a measurement reference position. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 3375439 [Patent Document 2] Japanese Patent Publication No. 2000-158169 [Overview of the project] [Problems that the invention aims to solve]

[0010] The methods described in Patent Documents 1 and 2 involve equipping a gantry frame with a shape measuring sensor and sequentially measuring shape data as viewed from above using the shape measuring sensor while horizontally moving the gantry frame in one direction.

[0011] In general, cutting operations involve moving the cutting machine at a constant speed over a specific area. Therefore, the amount of movement of the gantry frame of the cutting device is usually calculated based on the movement time. However, when performing shape measurements while moving the gantry frame, it is conceivable that the movement speed of the gantry frame may not always be constant.

[0012] When measuring shape, if the movement speed of the gantry frame is not constant, calculating the amount of movement by the movement time will result in inaccurate measurements of the gantry frame's movement. The longer the movement, the greater the measurement error. Poor accuracy in the measured movement amount leads to errors in the measurement position information of the shape data, which in turn reduces the accuracy of the shape data.

[0013] Furthermore, the above-mentioned documents also have the following problems. Specifically, the method in Patent Document 1 requires the installation of multiple shape measuring sensors in the width direction of the gantry frame in order to measure the shape of the material to be measured. In addition, since data acquired from multiple sensors is acquired over the entire length of the gantry frame in the direction of movement, there is a problem of the data size becoming enormous and the efficiency being poor. Also, in the cutting machine in Patent Document 2, when measuring the shape data of the material to be cut, sensing is performed by scanning the entire surface of the material to be cut with a distance sensor in a zigzag pattern. As a result, the cycle time increases and the size of the measurement data becomes enormous, resulting in poor efficiency.

[0014] This invention was made in view of the above-mentioned points, and aims to measure the shape of the material to be measured with greater accuracy. [Means for solving the problem]

[0015] To solve the problem, one aspect of the present invention involves using a shape measuring sensor that moves above a material to be measured to measure the shape of the material to be measured. The shape measuring sensor outputs a pulse signal each time it moves a predetermined unit distance, and the shape measuring sensor performs a measurement in synchronization with the output of the pulse signal. Shape data of the material to be measured is acquired by the shape measuring sensor, and the position information of the acquired shape data in the direction of movement is determined based on the product of the number of pulse signal outputs and the unit distance. [Effects of the Invention]

[0016] According to an aspect of the present invention, position information measured by the shape measuring sensor in the direction of movement of the shape measuring sensor is acquired based on the number of pulse signals output for each unit distance movement. Therefore, even if the movement speed of the shape measuring sensor for shape measurement is not constant, the above position information can be acquired with high accuracy.

[0017] At this time, the shape measurement sensor performs measurement in synchronization with the signal output for distance measurement. Therefore, the position information of the measurement data from the shape measurement sensor can be easily obtained from the number of pulse signals. In other words, information on the direction of movement of the shape measurement sensor, which constitutes the shape data, can be easily obtained. If the measurement data from the shape measurement sensor is two-dimensional data, it is possible to obtain three-dimensional shape information by adding the above position information. Thus, according to the embodiment of the present invention, it is possible to measure three-dimensional shapes with high accuracy even if the movement speed of the shape measurement sensor is not constant. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic side view showing an example of the configuration of a cutting apparatus according to an embodiment of the present invention. [Figure 2] This is a schematic top view showing an example of the configuration of a cutting apparatus according to an embodiment of the present invention. [Figure 3] This diagram illustrates a configuration for measuring unit distance. [Figure 4]It is a diagram showing a configuration example of a shape measurement device according to an embodiment based on the present invention. [Figure 5] It is a schematic diagram for explaining an example of a movement path. [Figure 6] It is a diagram for explaining the acquisition of correction information. [Figure 7] It is a diagram for explaining the relationship between the coordinates measured by a measuring machine and the number of pulses. [Figure 8] It is a diagram showing the relationship between the number of encoder pulses and the error correction amount.

Mode for Carrying Out the Invention

[0019] Next, embodiments based on the present invention will be described with reference to the drawings. The shape measurement device is a device that realizes the shape measurement method described below. In this embodiment, when manufacturing a product by cutting a thick plate conveyed to a cutting facility with a cutting device, the case where the shape of the thick plate is measured by the shape measurement device at at least one of before and after cutting will be described as an example. Hereinafter, the measurement target material will also be referred to as a thick plate.

[0020] <Measured material> The measurement target measured material is, for example, a thick plate made of metal such as steel, aluminum, or titanium. However, the material of the measured material may be resin or the like. Further, for non-contact measurement, the measurement target measured material is not particularly limited as long as it can maintain a certain shape. In the following embodiments, the case where the shape of the measured material is a thick plate having a rectangular shape (quadrilateral shape) in plan view will be described as an example. In this specification, the plan view refers to the appearance seen from the measurement direction. In this example, the plan view will be described as the top view.

[0021] Note that the present invention is not limited to the shape of the measured material in plan view being a rectangular shape, and may be other polygonal shapes, circular shapes, elliptical shapes, etc. Further, the present invention does not require the overall shape of the measured material to be flat.

[0022] <Cutting device> The cutting apparatus of this embodiment is, for example, a gantry-type cutting apparatus, which cuts a thick plate to a target shape by, for example, gas cutting.

[0023] As shown in Figures 1 and 2, the cutting apparatus 1 of this embodiment comprises two rails 3, a gate-type trolley 4, and a control unit 30. The trolley 4 is also equipped with a cutting device (not shown), which allows the thick plate, which is the material to be measured 11, placed in the area within the two rails 3, to be cut into the target shape. The control unit 30 drives and controls the movement of the trolley 4, etc., based on the route information supplied from the outside during cutting.

[0024] As shown in Figures 1 and 2, the trolley 4 is capable of traveling on a pair of laid rails 3 using wheels (not shown). Its direction of movement is the X-axis direction (horizontal direction: approximately the longitudinal direction of the material to be measured 11). The trolley 4 is driven by an X-axis drive unit 5, which acts as a linear motion device. As shown in Figure 3(b), the X-axis drive unit 5 is driven by a drive motor 5B which rotates a pinion gear 5A. By converting the amount of rotation of the pinion gear 5A into linear motion using an X-axis rack 6, the trolley 4 is able to move in the X-axis direction.

[0025] Furthermore, the trolley 4 is provided with a movable platform 7 that can move in the width direction. The width direction is the Y-axis direction (horizontal direction perpendicular to the X-axis direction: approximately the width direction of the material to be measured 11). The movable platform 7 is attached to the trolley 4 via a Y-axis drive device 8. The Y-axis drive device 8 is composed of a known linear motion device such as a ball screw device. In this embodiment, the pinion gear of the Y-axis drive device 8 is attached to the movable platform 7. The amount of rotation of the pinion gear is converted into linear motion by a Y-axis rack 9 fixed to the trolley 4, thereby enabling the movable platform 7 to move in the Y-axis direction.

[0026] A surface plate 10 is provided in the area between the rails 3, and the material to be measured 11, which is made of a thick plate, is placed on the surface plate 10 in a horizontal position.

[0027] In this embodiment, when manufacturing a product by cutting the material to be measured 11 (thick plate) with the cutting processing device 1, the placement position and dimensions of the material to be measured 11 are automatically measured by the shape measuring device at least one of the following: before cutting and after cutting. For example, shape measurement is performed before cutting to obtain the placement position of the rolled material to be processed and to determine whether the dimensions of the target product can be obtained. After cutting, shape measurement is performed to confirm whether the desired cutting process has been carried out. The shape measuring device of this embodiment is provided in the cutting device 1.

[0028] (shape measuring device) As shown in Figure 4, the shape measuring device of this embodiment includes a shape measuring sensor 2, a signal output unit 31, a signal counting unit 30A, a shape data acquisition unit 30B, a position information acquisition unit 30C, a shape calculation unit 30D, and a movement control unit 30E. The movable part of the shape measuring device is composed of the cutting device 1. In this embodiment, the shape measuring sensor 2 is provided on the gantry-type trolley 4 of the cutting device 1. Of the shape measuring device of this embodiment, the functional parts other than the shape measuring sensor 2 may be provided on the cutting device 1 or outside the cutting device 1.

[0029] <Shape measurement sensor 2> In this embodiment, the shape measuring sensor 2 is mounted on a mobile platform 7. This allows the shape measuring sensor 2 to move in the width direction relative to the trolley 4.

[0030] In this embodiment, a non-contact distance sensor using the light section method is exemplified as the shape measurement sensor 2. This distance sensor measures the two-dimensional surface shape of the thick plate 11 at the measurement position by irradiating the material to be measured 11 with a sheet-shaped laser beam and capturing the position of the laser beam from a different angle using a camera. The shape measurement sensor 2 may also employ a non-contact distance sensor using a method other than the light section method. However, the distance sensor using the light section method is a sensor capable of high-precision measurement.

[0031] <Shape data acquisition unit 30B> The shape data acquisition unit 30B controls the execution of shape measurement by the shape measurement sensor 2, triggered by a pulse signal output from the X-axis pulse output device 20 (described later). The pulse signal output from the X-axis pulse output device 20 is output in synchronization with the movement of the trolley 4 in the X-axis direction. The measured shape data is then sequentially saved to the storage unit. Note that data saving to the storage unit may be performed by other functional units.

[0032] Furthermore, the shape data acquisition unit 30B may be configured to control the execution of shape measurement by the shape measurement sensor 2 using a pulse signal output from the Y-axis pulse output device 21 (described later) as a trigger. The pulse signal output from the Y-axis pulse output device 21 is output in synchronization with the movement of the mobile platform 7 in the Y-axis direction. The shape measurement method described later illustrates a case where shape measurement is performed only when the trolley 4 moves in the X-axis direction.

[0033] In this embodiment, a measurement is performed each time a pulse signal is input. However, this is not limited to this. For example, the shape measurement sensor 2 may be set to perform a measurement every two pulse signals. The length of the unit distance can be determined according to the accuracy of the shape measurement.

[0034] In this example, since the material to be measured is rectangular in shape, it is preferable to position the material so that its longer side faces the X-axis and its shorter side faces the Y-axis. In this example, a light section distance sensor is used, and its light section direction is set to the Y-axis. This allows two-dimensional information of a region with a predetermined width in the Y-axis direction to be acquired each time a measurement is taken when the shape measurement sensor 2 is moved in the X-axis direction. Note that the unit distance in the X-axis direction and the unit distance in the Y-axis direction do not need to be the same value.

[0035] <Signal output section 31> The signal output unit 31 is a functional unit that outputs a pulse signal each time the shape measuring sensor 2 moves a predetermined unit distance. The signal output unit 31 in this embodiment has an X-axis pulse output device 20 and a Y-axis pulse output device 21.

[0036] The X-axis pulse output device 20 is configured to output a pulse signal each time the trolley 4 moves a unit distance in the X-axis direction. As shown in Figure 3, the X-axis pulse output device 20 includes a pinion gear 19 and a rotary encoder 18.

[0037] The pinion gear 19 meshes with the X-axis rack 6 and is capable of rolling along the X-axis rack 6. The rotation axis of the rotary encoder 18 is connected to the pinion gear 19. The rotary encoder 18 is fixed to the trolley 4. The rotary encoder 18 outputs a pulse signal at specified rotational intervals in response to the rolling of the pinion gear 19 caused by the movement of the trolley 4. In this embodiment, the pulse signal also serves as a measurement start signal for the shape measuring sensor 2.

[0038] Furthermore, the Y-axis pulse output device 21 is configured to output a pulse signal to the trolley 4 each time the mobile platform 7, i.e., the shape measuring sensor 2, moves a unit distance in the Y-axis direction. The basic configuration of the Y-axis pulse output device 21 is the same as that of the X-axis pulse output device 20. The Y-axis pulse output device 21 includes a Y-axis pinion gear and a Y-axis rotary encoder. The Y-axis pinion gear meshes with the Y-axis rack 9 and is capable of rolling along the Y-axis rack 9. The rotation axis of the Y-axis rotary encoder is connected to the Y-axis pinion gear. The Y-axis rotary encoder is fixed to the mobile platform 7. The Y-axis rotary encoder outputs a pulse signal at specified rotational intervals in accordance with the rolling of the Y-axis pinion gear caused by the movement of the mobile platform 7.

[0039] <Signal counting section 30A> The signal counting unit 30A is a functional unit that measures the number of pulse signals output by the signal output unit 31. The signal counting unit 30A of this embodiment includes a signal counting unit 30A for the X axis and a signal counting unit 30A for the Y axis.

[0040] The X-axis signal counting unit 30A is a functional unit that counts pulse signals output from the X-axis pulse output device 20. The Y-axis signal counting unit 30A is a functional unit that counts pulse signals output from the Y-axis pulse output device 21.

[0041] Each signal counting unit 30A can be configured, for example, with a counter board that counts pulse signals output from a rotary encoder. In this case, since the A and B phases of the two encoders in the X-axis and Y-axis directions are counted respectively, it is necessary to have four or more channels of counters that count pulse outputs from an external source. The counter length must be able to count a number of pulses obtained by dividing the upper limit of the movement amount (maximum measurement length) of the trolley 4 or mobile platform 7 by the unit distance. The maximum input frequency must be greater than the pulse output frequency calculated by dividing the maximum movement speed of the trolley 4 or mobile platform 7 by the unit distance. In this embodiment, the signal counting unit 30A resets the count to zero at the start of measurement.

[0042] <Location information acquisition unit 30C> The position information acquisition unit 30C determines the position information of each acquired shape data based on the product of the number of pulse signal outputs and the unit distance. Specifically, the position information acquisition unit 30C acquires position information in the X direction relative to a preset reference position based on the product of the number of pulse signals output during movement in the X direction and the unit distance. The position information acquisition unit 30C also acquires position information in the Y direction relative to a preset reference position based on the product of the number of pulse signals output during movement in the Y direction and the unit distance. Then, the position information acquisition unit 30C determines the position information at the time of measurement of each shape data from the number of pulse signals output during the measurement of each shape data measured by the shape measurement sensor 2.

[0043] In this embodiment, the position information acquisition unit 30C, for example, receives a pulse signal in the X-axis direction. The signal counting unit 30A then acquires the count number (number of pulse signal outputs) Nx after counting the pulse signal. The position information acquisition unit 30C then multiplies the count number Nx by the unit distance dX to obtain the amount of movement Lx in the X-axis direction from the measurement start position. The amount of movement Lx corresponding to the count number Nx when the shape data was measured is stored as the position information in the X-axis direction of the shape data acquired triggered by the pulse signal. The same process is performed for the Y-axis direction to obtain the amount of movement Ly in the Y-axis direction from the count number Ny, and the amount of movement Ly corresponding to the count number Ny when the shape data was measured is stored as the position information in the Y-axis direction of the shape data acquired triggered by the pulse signal. This allows obtaining the XY coordinates of the position information of the measured shape data. Then, the three-dimensional shape information data is constructed from the combination (Kn, Ln) of the shape data Kn measured by the shape measurement sensor 2 and the position information Ln measured by the position information acquisition unit 30C corresponding to the measurement of the shape data K.

[0044] The position information acquisition unit 30C may also have a correction information acquisition unit 30Ca. <Correction information acquisition unit 30Ca> The correction information acquisition unit 30Ca acquires correction information in advance to correct the error in the amount of movement per pulse signal from the calibration amount obtained by measuring the amount of movement of the shape measurement sensor 2 with a surveying instrument. Then, the position information acquisition unit 30C corrects the position information based on the acquired correction information.

[0045] <Shape calculation section 30D> The shape calculation unit 30D obtains shape information of the material to be measured from the group of shape information (Kn, Ln) measured from the start to the end of the measurement. The shape information of the material to be measured is, for example, the external dimensions. For example, if the shape of the material being measured is rectangular, the corners that define the rectangular shape are used as feature points, and the coordinates representing the four corners of the rectangular shape are calculated from the set of shape information (Kn, Ln). Then, the dimensions of the material being measured are calculated from the coordinates representing the four corners.

[0046] If feature points exist that identify the shape of the material being measured, the feature point existence region, which is the area where these feature points are estimated to exist, should be acquired, and only the 3D shape information data (Kn, Ln) within that feature point existence region should be stored in the memory unit. A smaller feature point existence region is preferable, but it must be set to a size that reliably includes the actual feature points.

[0047] When measuring the entire surface of the material being measured, the larger the material, the larger the data volume of the 3D shape information (Kn, Ln). In contrast, if only the 3D shape information data (Kn, Ln) for the region where feature points exist is saved, it is possible to reduce the amount of data to be stored.

[0048] <Movement control unit 30E> The movement control unit 30E controls the movement of the trolley 4 and the mobile platform 7 so that the shape measuring sensor 2 moves along the movement path. The movement of the shape measuring sensor 2 can be achieved by driving the X-axis drive unit 5 and the Y-axis drive unit 8. The movement path may be set, for example, based on the movement path during cutting, or the coordinates of the movement path during measurement may be set based on the target shape of the material being measured. In this embodiment, it is preferable that the trolley 4 moves only in the X-axis direction and the mobile platform 7 moves only in the Y-axis direction. That is, in this embodiment, the shape measuring sensor 2 is configured not to move simultaneously in the X-axis direction and the Y-axis direction. In the movement control unit 30E of this embodiment, when controlling shape measurement, the movement of the shape measuring sensor 2 in the X-axis direction (movement of the trolley 4) and the movement in the Y-axis direction (movement of the mobile platform 7) are controlled exclusively. The control of the movement of the trolley 4 and the mobile platform 7 is performed by drive control of the drive unit that drives the trolley 4 and the mobile platform 7 by known methods. At this time, the trolley 4 and the mobile platform 7 may be moved by manually supplying instructions to the drive unit, but it is preferable to have a locking mechanism that makes the movement of the trolley 4 and the mobile platform 7 exclusive. Of course, the movement of the trolley 4 and the mobile platform 7 may be performed non-exclusively.

[0049] (Shape measurement method) The shape measurement method is a method for measuring the shape of a material to be measured 11 using a shape measurement sensor 2 that moves above the material to be measured 11. The processing of the shape measurement method in this embodiment can be implemented, for example, using the shape measurement device described above. In the above description, an example was given in which the shape measurement sensor 2 is provided on the trolley 4 of the gate-type frame of the cutting processing device 1, but the method is not limited to this. Alternatively, a trolley 4 of the gate-type frame dedicated to shape measurement may be used, and the other parts may be configured to measure the shape of the material to be measured 11 using devices driven with the functional configuration described above.

[0050] The shape measurement method of this embodiment comprises a signal output step, a shape data acquisition step, and a position information acquisition step. A movement path planning step may be included before the signal output step.

[0051] <Travel route planning process> You may also create and store a pre-planned movement path for the shape measurement sensor 2 (movement path plan). If a movement path is not created in advance, the shape measurement process can be carried out as follows, for example: The shape information data is acquired by manually moving the trolley 4 and mobile platform 7 of the shape measuring device along the contour of the material to be measured 11. In contrast, by creating a movement path plan in advance, the movement operation of the shape measurement sensor 2 can be automated.

[0052] The movement path plan includes a list of coordinate points formed by connecting the paths along which the shape measurement sensor 2 moves with straight lines, and the movement path includes information on the positions where the shape measurement sensor 2 measures the shape of the material to be measured 11 and the positions where it does not measure.

[0053] Table 1 shows an example of a travel path plan. Figure 5 shows an example of the coordinate point locations in Table 1. [Table 1]

[0054] Specifically, as shown in Figure 5, multiple coordinate points P1 to Pn are set along the contour shape of the outer circumference of the material to be measured to define its external shape. The movement of the trolley 4 and the moving body is controlled so that the shape measurement sensor 2 moves sequentially in a straight line between the coordinate points P1 to Pn described in the movement path plan. In addition to the coordinate points, a flag indicating the measurement start position is set in the movement path plan, as shown in Table 1. With this setting, the value of the flag is changed each time the system moves to a different coordinate point. This ensures that shape measurement is performed only while moving from a coordinate point where the flag is 1 to the next coordinate point. At this time, the shape measurement sensor 2 measures and saves shape data in synchronization with the pulse signal output for movement in the X-axis direction. In Figure 5, the region ARA is the measurement area for shape measurement. This region ARA corresponds to the area where feature points exist.

[0055] In other words, the flag is set so that feature points that identify the shape of the material being measured are set in the region defined between the coordinate point where the flag is 1 and the next coordinate point. In this example, since the material being measured is a rectangular (polygonal) plate, the corner radius R was used as a feature point, as shown in Figure 5. The region containing the corner radius R, which is the feature point, was then set as the region where the feature point exists.

[0056] The region where feature points existed was defined as the measurement location by the shape measurement sensor 2, and the region defined by the other paths was defined as the non-measurement region. It is preferable to save only the measurement data measured by the shape measurement sensor 2 while moving from a coordinate point where flag is 1 to the next coordinate point. In this case, only the shape data of the necessary locations is saved, making it possible to reduce the size of the measured shape data.

[0057] <Signal output process> The signal output process involves outputting a pulse signal each time the shape measuring sensor 2 moves a predetermined unit distance.

[0058] In this embodiment, the signal output process is performed by the signal output unit 31. The signal output process outputs pulse signals in accordance with the movement of the shape measuring sensor 2 in the XY direction due to the movement of the gantry-type trolley 4 and the mobile platform 7 provided on the trolley 4. Specifically, rectangular pulse signals are output from the X-axis pulse output device 20 and the Y-axis pulse output device 21, respectively.

[0059] The pulse signal is output in two parts: phase A and phase B, which are generated when the rotation axis of the rotary encoder 18 rotates by the angular resolution. Phases A and B are output with a 90° phase difference.

[0060] <Shape data acquisition process> The shape data acquisition process involves performing measurements with the shape measuring sensor 2 in synchronization with the pulse signal output during the signal output process. This process acquires shape data of the material being measured using the shape measuring sensor 2.

[0061] For example, in the shape data acquisition process, when an X-axis encoder pulse signal is input to the shape measurement sensor 2, the shape measurement sensor 2 performs a measurement and saves the measurement data.

[0062] However, when acquiring information only in the feature point region, the system is controlled to save measurement data only when flag is 1 (see Table 1), and not save measurement data in movement paths where flag is 0. In other words, the control unit refers to the information in Table 1 and, when it determines that the current coordinate position of the shape measurement sensor 2 has reached or passed each coordinate point, it sets the flag content of that coordinate point to flag. Then, in the shape data acquisition process, the shape measurement sensor 2 performs a measurement only when flag is determined to be 1, at the timing when a pulse signal is input from the X-axis encoder.

[0063] In the example in Table 1, as shown in Figure 5, the shape measurement sensor 2 performs measurements synchronized with the pulse signal only when it is moving in the X-axis direction. If measurements are also to be performed when the shape measurement sensor 2 is moving in the Y-axis direction, the shape measurement sensor 2 should be configured to perform measurements when a pulse signal is input from the Y-axis encoder.

[0064] Furthermore, in this example, the shape measurement sensor 2 is a light section type sensor. Therefore, the measurement data measured in synchronization with the encoder pulse signal in the X-axis direction consists of measurement data for regions having a width in the Y-axis direction. When measuring in synchronization with the encoder pulse signal in the Y-axis direction, it is preferable to have a mechanism to change the light section direction of the shape measurement sensor 2 in the X-axis direction.

[0065] Furthermore, as shown in Figure 5, each coordinate point may be offset from the actual edge position of the material being measured. However, if the amount of offset is less than half of the measurement width (width in the direction of light section) of the shape measurement sensor 2, the edge position of the material being measured can be detected by the shape measurement sensor 2. In addition, the coordinates of coordinate points P1, P4, P5, and P8 are set to be located outside the expected corners of the material being measured in the X-axis direction, making it easier to acquire corner information.

[0066] <Signal counting process> In the signal counting process, the signal counting unit 30A counts the number of pulse signals output in the pulse output process. The count is cleared at a reference point, and the coordinates of this reference point are set as the origin.

[0067] When the shape measurement sensor 2 moves along the path shown in Table 1, the coordinate point P0 is used as the reference point, and the number of pulses in the X and Y axes is saved when the shape measurement sensor 2 reaches each coordinate point P1, P2, ... P8. In this case, the position of the shape measurement sensor 2 can be expressed as (number of pulses in the X-axis direction, number of pulses in the Y-axis direction).

[0068] The amount of movement dX in the X-axis direction of the shape measuring sensor 2 can be calculated using the formula dX = L / N, where N is the number of pulses output per revolution of the X-axis encoder and L is the amount of movement of the gantry cutting machine per revolution of the encoder.

[0069] <Location information acquisition process> The position information acquisition process determines the position information of the acquired shape data based on the product of the number of pulse signal outputs and the unit distance. Furthermore, based on the product of the number of pulse signal outputs and the unit distance, it is possible to obtain the position coordinates of the shape measurement sensor 2 at a specific time, such as the current position of the shape measurement sensor 2.

[0070] The position information acquisition process multiplies the current number of pulse signals in the X-axis direction and the number of pulses in the Y-axis direction by a unit distance. This determines the current position coordinates of the shape measurement sensor 2. When it is determined that these position coordinates have reached or passed through each coordinate point, the total number of pulses from the reference point is stored for each coordinate point.

[0071] Furthermore, in the position information acquisition process, if it is determined that the location is within the feature point region (flag=1), the position coordinates of the shape measurement sensor 2 at that time are saved together with the corresponding shape data, in synchronization with the output of the pulse signal. The position coordinates are the value obtained by multiplying the number of pulse signal outputs by the unit distance.

[0072] Here, the position coordinates of each coordinate point and the shape measurement sensor 2 may be expressed as (number of pulses in the X-axis direction, number of pulses in the Y-axis direction), and the above processing may be performed. When actual length, etc., is required, such as for shape information acquisition, the number of pulses can be multiplied by the unit distance to convert it into length information.

[0073] <Shape calculation process> The measurement data can be expressed, for example, as follows: Here, coordinate point P0 is represented as the coordinates (Xstart, Ystart) of the measurement start position. Also, the pulse counter count value at the measurement start position within the feature point existence region (the region where flag is 1 in Table 1) is represented as (XCount, YCount). Furthermore, the number of pulses in the X direction counted from the measurement start position (XCount, YCount) within the feature point existence region is represented as (Xdata).

[0074] In this case, the measurement data (Data1, Data2, ..., DataN) measured by the shape measurement sensor 2 during the shape measurement process is stored as (M × N) two-dimensional matrix height data.

[0075] Here, each data point from a single measurement by the shape measurement sensor 2 is represented in the form of a one-dimensional matrix consisting of multiple distance information (height information) arranged along the Y-axis. This data is acquired each time the feature point moves a unit distance in the X-axis direction within the feature point region, resulting in the two-dimensional matrix data described above.

[0076] Furthermore, by adding the location information obtained in the location information acquisition process to the height data in the above-mentioned two-dimensional matrix format, three-dimensional shape information data can be obtained.

[0077] Specifically, let's assume the coordinates of the movement path of the shape measurement sensor 2 are denoted as (X[i,j],Y[i,j],Z[i,j]). In this case, the coordinates can be calculated using the following equations (1), (2), and (3).

[0078] X[i,j] = (Xstart[i] + Xdata[i] + Xcount[i]) ×dX ···(1) Y[i,j] = (Ystart[i] + Ydata[i] + Ycount[i]) × dY + dl * j ···(2) Z[i,j] = Data[i,j] ···(3)

[0079] Here, i,j: Data from row i and column j of the measurement data, respectively. dX, dY: Unit distances in the X and Y directions, respectively. dl: Measurement data interval of shape measurement sensor 2 (distance measurement interval aligned in the direction of light cutting) That is the case.

[0080] <Method for correcting errors in the amount of movement per pulse> Here, by moving the trolley 4 and the mobile platform 7 using a linear motion device, errors due to slippage during movement are small, and the accuracy of calculating the amount of movement based on the number of pulse signals is high.

[0081] However, wear on the pinion gear teeth due to use can cause errors in the amount of movement per pulse that exceed the required level. The higher the accuracy required for shape measurement, the more problematic the impact of these errors becomes. In this case, for example, by correcting the amount of movement of the trolley 4 or the mobile platform 7 per pulse using the method described below, high-precision 3D shape measurement can be performed.

[0082] [Correction information acquisition process] The correction information acquisition process involves acquiring correction information in advance to correct the error in the amount of movement per pulse signal, based on the calibration amount obtained by measuring the amount of movement of the shape measuring device using a surveying instrument. Then, the location information acquisition process corrects the location information based on the obtained correction information.

[0083] Let me explain a specific example of the process. As a preliminary step to shape measurement, the following correction information acquisition process is performed. As shown in Figure 6, the surveying instrument 12 is installed outside the movable range of the gantry-type cutting device 1, and the target 13 is installed on the shape measuring sensor 2. In this embodiment, in order to correct the amount of movement in the X-axis direction and the Y-axis direction, correction information for the X-axis direction and the Y-axis direction is obtained separately, as shown in Figures 6(a) and (b). For this reason, as shown in Figure 6, the surveying instrument 12 is installed separately for the X-axis direction and the Y-axis direction to measure the distance associated with the movement of the shape measuring sensor 2. The process is the same, so it will be explained mainly in terms of the X-axis direction. In Figure 6, the area between reference numerals 14 and 15 indicates the movement range of the trolley 4 for acquiring correction information. Also, the area between reference numerals 16 and 17 indicates the movement range of the mobile platform 7 for acquiring correction information. The surveying instrument 12 consists of optical distance meters, such as a laser distance meter, which measures the horizontal direction. By using the surveying instrument 12, which consists of distance meters, it is possible to measure distance with high precision. However, when actually measuring the shape, constantly measuring the amount of movement with a distance meter is difficult to use considering interference with other parts.

[0084] The surveying instrument 12 measures the relative distance to the target 13 and determines the coordinates of the target 13 from the measured value. In this process, the entire operating range of the shape measuring sensor 2 is divided into intervals of a certain length dL from the starting position to the ending position, and the coordinates of the gantry cutting machine 1 at each point are measured by the surveying instrument 12, while the count of the pulse signal is recorded.

[0085] For example, the absolute coordinates of the shape measuring sensor 2 when it is moved in the X-axis direction are measured using the surveying instrument 12, and this true value of the amount of movement is used as the amount of movement for calibration.

[0086] Then, a function is created between the count of the pulse signals recorded in this process and the coordinates measured by the surveying instrument 12. The function is, for example, a function that represents the state shown in Figure 7. The function corresponds to the correction information. In this way, the correction information can be obtained by comparing the amount of movement for calibration with the amount of movement obtained from the unit distance per pulse signal of the shape measurement sensor 2.

[0087] In the position information acquisition process, the correction amount for the coordinates of the shape measurement sensor 2 relative to the pulse signal count is determined based on that function. Then, the measurement error of the coordinates (amount of movement) caused by the error in the pulse signal count is corrected with that correction amount. The correction should only be performed when determining the position. It is not necessary to perform it every time a pulse signal is input.

[0088] Furthermore, it is preferable to perform measurements using the surveying instrument 12, for example, during equipment maintenance, and to update the above function as appropriate.

[0089] (Operation and other functions) In this embodiment, position information measured by the shape measuring sensor 2 in the direction of movement is acquired based on the number of pulse signals output for each unit distance moved. Furthermore, the coordinates of the starting position of the shape measurement can also be accurately determined based on the number of pulse signals output for each unit distance moved. Therefore, even if the movement speed of the shape measuring sensor 2 for shape measurement is not constant, each position information can be acquired with accuracy.

[0090] In this case, using a linear motion device for movement suppresses slippage during movement, allowing for highly accurate movement. Furthermore, using a rotary encoder ensures reliable detection of movement by a unit distance.

[0091] Furthermore, in this embodiment, measurement by the shape measuring sensor 2 is performed in synchronization with the output of a pulse signal for distance measurement. As a result, position information of the measurement data by the shape measuring sensor 2 can be easily obtained from the number of pulse signals. That is, information on the direction of movement of the shape measuring sensor 2, which constitutes the shape data, can be easily obtained. If the measurement data by the shape measuring sensor 2 is two-dimensional data, it is possible to obtain three-dimensional shape information by adding the above position information. Thus, according to the embodiment of the present invention, it is possible to measure a three-dimensional shape with high accuracy even if the movement speed of the shape measuring sensor 2 is not constant.

[0092] Alternatively, instead of measuring the shape of the entire outer circumference of the material to be measured, the system may be configured to perform shape measurements only on specific regions where the shape of the material can be identified. In this case, as in this embodiment, it is sufficient to simply save the number of pulses at the start and end positions of the measurement in the specific region. As a result, it is possible to reduce the data size of the 3D shape data compared to methods that measure the entire area of ​​the object to be measured.

[0093] Furthermore, by correcting the movement amount of the shape measurement sensor 2 based on the calibration movement amount, it becomes possible to perform 3D shape measurement with higher accuracy.

[0094] In the above embodiment, since the cutting of a thick plate is assumed, an example was given in which the flatness of the outer edge of the material to be measured and the external dimensions of the material to be measured are determined in order to confirm the effect of the cutting. When measuring the flatness of the entire top surface of the material to be measured, the movement path of the shape measurement sensor 2 should be set according to the purpose of measurement.

[0095] (others) This disclosure may also take the following form: (1) Disclosure 1 is a shape measuring method for measuring the shape of a material to be measured using a shape measuring sensor that moves above the material to be measured, The above shape measuring sensor outputs a pulse signal each time it moves a predetermined unit distance, and A shape data acquisition step is performed by performing a measurement with the shape measuring sensor in synchronization with the output of the pulse signal, thereby acquiring shape data of the material to be measured by the shape measuring sensor. A position information acquisition step is performed to determine the position information of the acquired shape data based on the product of the number of pulse signals output and the unit distance. A shape measurement method comprising the following features. (2) Disclosure 2 detects the movement of the shape measuring sensor by a unit distance using a rotary encoder. The shape measurement method described in Disclosure 1. (3) Disclosure 3 acquires correction information in advance to correct the error in the amount of movement per pulse signal, based on the amount of movement of the shape measuring sensor measured by a surveying instrument and obtained for calibration, In the above location information acquisition process, the above location information is corrected based on the above correction information. A shape measurement method as described in Disclosure 1 or 2. (4) Disclosure 4 moves the shape measuring sensor along a predetermined movement path, The movement path is set along the outer circumference of the material being measured. A shape measurement method as described in any of disclosures 1 to 3. (5) Disclosure 5 states that the material to be measured is a material before or after cutting which is cut into the desired shape by a cutting device. The above shape measuring sensor is installed in the above cutting device. A shape measurement method as described in any of Disclosures 1 to 4. (6) Disclosure 6 acquires two or more feature point existence regions, which are regions where it is estimated that feature points that identify the shape of the material to be measured exist, Shape measurement using the above-mentioned shape measurement sensor is performed only in the region where the feature points exist. A shape measurement method as described in any of disclosures 1 to 5. (7) Disclosure 7 states that the material to be measured is a polygonal plate material, The corners of the above-mentioned plate material are set as the characteristic points described above. The shape measurement method described in Disclosure 6. (8) Disclosure 8 is a shape measuring device that measures the shape of a material to be measured using a shape measuring sensor that moves above the material to be measured, The above shape measuring sensor has a signal output unit that outputs a pulse signal each time it moves a predetermined unit distance, A shape data acquisition unit acquires shape data of the material to be measured by the shape measurement sensor by performing measurements in synchronization with the output of the pulse signal output by the signal output unit, A signal counting unit that measures the number of pulse signals output by the above-mentioned signal output unit, A position information acquisition unit that determines the position information of the acquired shape data based on the product of the number of pulse signals output and the unit distance, A shape measuring device equipped with the following features. (9) Disclosure 9 states that the signal output unit detects the movement of the shape measuring sensor by a unit distance using a rotary encoder, The shape measuring sensor described above is configured to move using a linear motion device. The shape measuring device described in Disclosure 8. (10) Disclosure 10 states that the material to be measured is a material that has been cut into the desired shape by a cutting device, The above shape measuring sensor is installed in the above cutting device. A shape measuring device as described in Disclosure 8 or 9. (11) Disclosure 11 is a method for manufacturing a product by processing a material to be measured, The shape of the material to be measured, at least one of the before and after processing, is measured using a shape measuring device described in any of disclosures 8 to 10. Product manufacturing method. [Examples]

[0096] Next, an example based on this embodiment will be described. In this embodiment, a gantry-type cutting machine was equipped with an optical section profiler (a distance sensor for optical sectioning) as the shape measurement sensor 2. Furthermore, the material to be measured 11 was a rectangular metal plate, and the shape of the metal plate was measured.

[0097] As shown in Figure 5, the shape measurement sensor 2 was moved along the movement path described in the embodiment (see Figure 5) to acquire shape data, and the shape data (including position information) of the metal plate was obtained as a 3D point cloud. The feature point region was defined as the region to be measured (near the corners of the metal plate), and shape measurement was performed only in that region.

[0098] For comparison, we calculated the movement of shape measurement sensor 2 using a set distance per unit time for the movement time, and obtained similar 3D shape data. Furthermore, when comparing the 3D shape data of the embodiment based on this example with the comparative 3D shape data, it was confirmed that the 3D shape data of this embodiment had higher accuracy.

[0099] Furthermore, Figure 8 shows an example of error correction performed on the movement amount of the gantry-type cutting machine (shape measurement sensor 2) in this embodiment. In this example, the movable range of the gantry-type trolley 4 in the X direction was set to a section of 10m, and it was moved intermittently within that section at 50mm intervals. The number of encoder pulses at each stopping position and the coordinates of the trolley 4 measured by the surveying instrument 12 were then determined. The surveying was performed using the method shown in Figure 6.

[0100] The error correction amount on the vertical axis of Figure 8 represents the error obtained by taking the difference between the coordinates measured by the surveying instrument 12 and the coordinates calculated from the number of encoder pulses. Thus, by pre-measuring the coordinates of the gantry-type cutting machine with the surveying instrument 12, it is possible to correct the error in the coordinates measured from the encoder pulse count. [Explanation of symbols]

[0101] 1 Cutting equipment 2 Shape measurement sensor 4 carts 5 X-axis drive unit 5A Pinion Gear 5B drive motor 6 X-axis rack 7 Mobile platform 8. Y-axis drive unit 9 Y-axis racks 10 Surface plate 11. Material to be measured (thick plate) 12 Surveying equipment 13 Targets 18 Rotary Encoders 19 Pinion Gear 20 X-axis pulse output device 21 Y-axis pulse output device 30 Control Unit 30A Signal Counting Unit 30B Shape data acquisition unit 30C Location information acquisition section 30D shape calculation section 30E Movement Control Unit 31 Signal output section ARA Feature point location region (measurement region)

Claims

1. A shape measurement method for measuring the shape of a material to be measured using a shape measuring sensor that moves above the material to be measured, The above shape measuring sensor outputs a pulse signal each time it moves a predetermined unit distance, and A shape data acquisition step is performed by performing a measurement with the shape measuring sensor in synchronization with the output of the pulse signal, thereby acquiring shape data of the material to be measured by the shape measuring sensor. A position information acquisition step is performed to determine the position information of the acquired shape data based on the product of the number of pulse signals output and the unit distance. A shape measurement method comprising the following features.

2. The movement of the above shape measuring sensor by a unit distance is detected by a rotary encoder. The shape measurement method described in claim 1.

3. Based on the calibration displacement obtained by measuring the displacement of the above shape measuring sensor using a surveying instrument, correction information is acquired in advance to correct the error in the displacement per pulse signal. In the above location information acquisition process, the above location information is corrected based on the above correction information. The shape measurement method described in claim 1.

4. The shape measuring sensor is moved along a predetermined movement path. The movement path is set along the outer circumference of the material being measured. The shape measurement method described in claim 1.

5. The material to be measured above is the material before or after cutting, which is cut into the desired shape by a cutting device. The above shape measuring sensor is installed in the above cutting device. The shape measurement method described in claim 1.

6. Obtain two or more feature point locations, which are regions where it is estimated that feature points that identify the shape of the material being measured exist. Shape measurement using the above-mentioned shape measurement sensor is performed only in the region where the feature points exist. A method for measuring shape as described in any one of claims 1 to 5.

7. The material being measured is a polygonal plate, The corners of the above-mentioned plate material are set as the characteristic points described above. The shape measurement method described in claim 6.

8. A shape measuring device that measures the shape of a material to be measured using a shape measuring sensor that moves above the material to be measured, The above shape measuring sensor has a signal output unit that outputs a pulse signal each time it moves a predetermined unit distance, A shape data acquisition unit acquires shape data of the material to be measured by the shape measurement sensor by performing measurements in synchronization with the output of the pulse signal output by the signal output unit, A signal counting unit that measures the number of pulse signals output by the above-mentioned signal output unit, A position information acquisition unit that determines the position information of the acquired shape data based on the product of the number of pulse signals output and the unit distance, A shape measuring device equipped with the following features.

9. The above signal output unit detects the movement of the shape measuring sensor by a unit distance using a rotary encoder. The shape measuring sensor described above is configured to move using a linear motion device. The shape measuring device described in claim 8.

10. The material to be measured above is a material that has been cut into the desired shape using a cutting device. The above shape measuring sensor is installed in the above cutting device. The shape measuring device described in claim 8.

11. A method for manufacturing a product by processing a material to be measured, The shape of the material to be measured, at least one of the material before processing and after processing, is measured using the shape measuring device described in any one of claims 8 to 10. Product manufacturing method.

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