JPH059222B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for measuring the amount of clamp deviation of a material clamped on a table of a material processing machine.

[Technical background of the invention and its problems] Generally, when a material clamped on the table of a processing machine is automatically processed under the control of an NC device, the material itself needs to be clamped in the correct position. . For this reason, a clamp displacement amount measuring device using a visual sensor has been used.
This conventional clamp deviation measurement device is shown in Fig. 9a.
As shown in the figure, a reference hole 1 is provided in the material W, and an image around this reference hole is taken in by a visual sensor, and the center coordinates X ₁ , Y ₁ of the reference hole 1 are determined with respect to an arbitrary point in the image. Calculate as points. Then, as shown in FIG _.
Compare Y ₀ and set the clamp deviation amount ΔX, ΔY as the first
It was calculated as shown in Figure 0 and outputted to an NC device etc. to detect clamp misalignment.

However, when measuring the coordinates of the center point C of the reference hole 1, such a conventional clamp deviation measuring device calculates a distance from an arbitrary point on the image as the reference point RP. Therefore, even if the material is in a fixed state, if the measurement axis of the visual sensor shifts during movement due to mechanical vibration or other causes, the reference point
There is a problem in that the distance between the center point C of the reference hole 1 and the RP actually changes, and the amount of deviation of this visual sensor is added to the amount of clamp deviation, reducing measurement accuracy. When measuring the amount of deviation, there was a problem in which the amount of deviation became audible.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and is designed so that a mark provided on a table appears in a reference hole of a material. When the vision sensor captures an image of the reference hole, it also captures the mark serving as the reference point at the same time, so that even if the visual sensor is shaken, the relative position between the center point of the reference hole and the mark is ensure that the positional relationship is always kept constant. Therefore, measure the center coordinates of the reference hole using that mark as a reference point,
It is an object of the present invention to provide a clamp deviation amount measuring device that can accurately measure the amount of clamp deviation of a material by measuring the amount of clamp deviation by comparison with a regular positional relationship.

[Structure of the Invention] In order to achieve the above object, the present invention provides a clamper that grips and moves a material W on a table in a processing machine, and a reference hole provided in the material moved by the clamper. When positioned at the mark provided at a predetermined position on the table,
A visual sensor that simultaneously images the reference hole and the mark is provided in the processing machine, and the center point of the reference hole and the center point of the mark are calculated based on the video signal from the visual sensor, and the center point of the mark is calculated. The center coordinates of the reference hole are calculated using the reference point as the reference point, and the center coordinates of the reference hole are compared with the center coordinates of the reference hole at a regular position stored in advance in memory to determine the clamping deviation of the material with respect to the clamper. It is equipped with an image processing device that calculates the amount and provides it to the NC device.

[Embodiment of the Invention] FIG. 1 shows the entire processing machine 13 with an NC device 11, in which a visual sensor 15 is provided, and a material W is fixed on a table 17 by a clamper 19. It is configured to When measuring the amount of clamp deviation, the reference hole 21 of the material W is positioned directly below the visual sensor 15 by moving the table 17 in the XY and two-axis directions, and the coordinates of the center position of the reference hole 21 are adjusted according to the specified coordinates. It is determined whether the material W is clamped in the correct position based on whether or not the material W is clamped in the correct position.

In order to determine the coordinates of the center position of the reference hole 21 with respect to such a reference point using the visual sensor 15,
The configuration shown in FIGS. 2 and 3 is adopted.
A window 23 is formed in the table 17 at a portion corresponding to the reference hole 21 of the material W thereon, and a translucent material plate 25 shown in FIG. 4 is fitted into this window 23. A mark 27 is attached to the semi-transparent plate 25. A light source 29 for illumination is provided below the window 23 of the table 17. The visual sensor 15 is a solid-state imaging device such as an ITV camera or a CCD, and sends a video signal 3 to an image processing device 31.
It is configured to convey 3.

As shown in FIG. 5, this image processing device 31 includes an A/D converter 35 that converts the video signal 33 from the visual sensor 15 into a digital signal, and a frame memory 37 that stores the digital signal from the A/D converter 35. , a CPU 39 for processing the image signal of this frame memory 37, a ROM 41, a RAM 43,
Furthermore, input and output signals to and from external devices.
Equipped with Di/Do45.

The operation of the clamp deviation amount measuring device having the above configuration will be explained next. As shown in FIG. 1, the material W is placed on a table 17 and clamped at a predetermined position by a clamper 19. A reference hole 21 is provided at a predetermined position of this material W.

To measure the amount of clamp deviation, the material W on the table 17 is moved by the clamper 19 until the reference hole 21 of the material W is directly above the window 23 of the table 17, as shown in FIG. and simultaneously move it so that it is located directly below the visual sensor 15. The light source 29 illuminates the reference hole 21 through the semi-transparent plate 25, and the visual sensor 15 simultaneously images the reference hole 21 and the mark 27 on the semi-transparent plate 25 immediately below the reference hole 21,
The video signal 33 is sent to the image processing device 31.

In the image processing device 31, the A/D converter 35 stores the sent video signal as a digital signal in the frame memory 37, and calculates the center coordinates x ₁ , y ₁ of the reference hole 21 and the coordinates x ₂ , Find y ₂ .

The details of this process will be explained in detail based on FIGS. 6 to 8. First, the digital image data stored in the frame memory 37 is binarized to obtain binary image data (steps 51 and 52). Next, the shape of the reference hole 21 and the shape of the mark 27 are divided from this binary image data using a region division processing algorithm to obtain a divided image (step 53,
54). Then, from this divided image, the reference hole 21
center coordinates x ₁ , y ₁ , coordinates of the center point of mark 27
Find x ₂ and y ₂ (step 55).

This process is performed as the average value of the coordinate points that make up each shape, and is based on equation (1) shown below.

χa= _o 〓 ⁱ⁼¹ (χai)/n ya= _o 〓 ⁱ⁼¹ (yai)/n...(1) a=1, 2 (χai ₁ , ya ₁ ), (χa ₂ , ya ₂ ),... , (χan, yan):
Coordinate points forming the reference hole 21 or mark 27 From now on, the reference hole 21 with mark 27 as the reference point
Find the center coordinates (χ ₁ , y ₁ ) of This process is performed using the following equation (2).

X ₁ = χ ₁ − χ ₂ Y ₁ = y ₁ − _{y 2} …(2) X ₁ and Y ₁ obtained in this way are placed at the regular positions that have been measured and memorized in advance by the same process. Compare the center coordinates X ₀ and Y ₀ of the reference hole of the clamped material, calculate the clamping deviation amounts ΔX and ΔY in both the χ-axis and y-axis directions using equation (3) below, and calculate this using the NC device. The output is output to a position display device or other I/O means to notify the operator of the amount of clamp deviation.

ΔX=X ₁ −X ₀ ΔY=Y ₁ −Y ₀ (3) Note that the regular center coordinates X ₀ and Y ₀ of the reference hole 21 when the material W is clamped at the above regular position are determined in the teaching mode. It is assumed that the measurement is performed and stored in the RAM 43 of the image processing device 31 shown in FIG. When measuring the amount of clamp displacement during actual material processing, the amount of clamp displacement of the material W is measured according to the above procedure, the coordinates X ₁ and Y ₁ of the reference hole 21 are determined, and the CPU 39 The coordinates are compared with the regular coordinates X ₀ and Y ₀ in the teaching mode stored in the RAM 43, and the deviation amounts ΔX and ΔY are determined and provided to the NC device.

[Effects of the Invention] As can be understood from the description of the embodiments above, the present invention provides a clamper 1 that grips and moves a material W on a table in a processing machine 13.
9, and a reference hole 21 provided in the material W moved by the clamper 19 is inserted into the table 1.
When the processing machine 1 is positioned at the mark 27 provided at a predetermined position of the processing machine
3, and the video signal 3 from the visual sensor 15 is
3, the center points x ₁ , y ₁ of the reference hole 21 and the center points x 2 , y ₂ of the mark 27 are calculated, and the center points x ₂ , y ₂ of the mark 27 are set as the reference points _. The center coordinates of the reference hole 21 are calculated as X ₁ , Y ₁ and the center coordinates X ₁ , Y ₁ and the center coordinates X ₀ , Y 1 of the reference hole 21 at the regular position stored in advance in the memory are calculated.
The apparatus is equipped with an image processing device 31 which calculates clamper deviation amounts ΔX and ΔY of the material W with respect to the clamper 19 by comparing Y ₀ with Y 0 and provides the results to the NC device 11 .

As is clear from the above configuration, in the present invention, a mark 27 is provided at a predetermined position on the table 17 of the processing machine 13. And clamper 1
There is a reference hole 2 in the material W that is gripped and moved by 9.
1 is provided, and the reference hole 21 is connected to the workpiece 2.
The processing machine 13 is provided with a visual sensor 15 that simultaneously images the reference hole 21 and mark 27 when positioned at position 7.

Then, the video signal 3 from the visual sensor 15 is
3, the center positions of the reference hole 21 and the mark 27 are respectively calculated, the deviation of the center of the reference hole 21 from the center of the mark 27 is calculated, and the center coordinates of the reference hole 21 are calculated. and,
The amount of clamping deviation of the material W with respect to the clamp 19 is calculated by comparing these center coordinates with the center coordinates of the reference hole 21 in a normal state stored in advance.

That is, in the present invention, for example, even though the workpiece origin of the material W is aligned with the machine origin of the processing machine 13 and the material W is gripped by the clamp 19, the material W is misaligned with respect to the clamp 19. In certain cases, it is possible to detect the amount of deviation. In this case, even if the visual sensor 15 is slightly moved due to vibration or the like,
Since the deviation can be detected using the mark 27 provided on the table 17 as a reference, the amount of deviation can always be accurately detected.

[Brief explanation of the drawing]

Fig. 1 is an overall view of an embodiment of the present invention, Fig. 2 is a perspective view showing the positional relationship between the table and the visual sensor of the above embodiment, and Fig. 3 is a measurement of the amount of clamping deviation of a material according to the above embodiment. 4 is a perspective view of the translucent plate attached to the window of the table in the above embodiment; FIG. 5 is a block diagram of the image processing device;
Figure 6 is an image processing flowchart in the image processing device, Figure 7 is a plan view showing the coordinates of the center point of the reference hole and the center point of the mark, and Figure 8 is the position of the center coordinates of the reference hole relative to the center point of the mark. FIGS. 9 and 10 are plan views showing the relationship, and FIGS. 9 and 10 are plan views showing a procedure for measuring the amount of material clamp deviation according to a conventional example. 11...NC device, 13...processing machine, 15...
Visual sensor, 17... table, 19... clamper, 21... reference hole, 23... window, 25... translucent plate, 27... mark, 29... light source, 31...
Image processing device.

Claims (1)

[Claims] 1 Material W on table 17 in processing machine 13
A clamper 19 is provided which grips and moves the material W, and when a reference hole 21 provided in the material W moved by the clamper 19 is positioned at a mark 27 provided at a predetermined position on the table 17, the reference hole 21 is moved by the clamper 19. A visual sensor 15 for simultaneously capturing images of the hole 21 and the mark 27 is provided in the processing machine 13, and based on the video signal 33 from the visual sensor 15, the center point x ₁ , y ₁ of the reference hole 21 and the mark 27 are determined. Calculate the center points x ₂ and y ₂ and find the center point of the mark 27 above.
Center coordinates of the reference hole 21 with x ₂ , y ₂ as reference points
X ₁ , Y ₁ are calculated, and the center coordinates X ₁ , Y ₁ are compared with the center coordinates X ₀ , Y ₀ of the reference hole 21 at the regular position stored in advance in the memory, and the clamper 1. A clamp deviation amount measuring device comprising an image processing device 31 which calculates clamper deviation amounts ΔX and ΔY of a material W with respect to 19 and provides the calculated results to an NC device 11.