JPH0418926B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting the bending angle of a plate material when the plate material is being bent by a bending machine such as a press brake.

Conventionally, the bending angle in a bending machine is controlled by performing a trial bend in advance, measuring the bending angle with a cage, etc., and adjusting the pushing distance of the upper die relative to the lower die according to the results. As a result, this has been done by setting the pushing distance to an appropriate value in advance. However, since the bending angle is an important factor in product accuracy, it has been desired to develop a means that can accurately detect and control the bending angle during the bending process.

Moreover, in recent years, with the development of robots, etc., it has become possible to continuously supply workpieces to the bending machine in a short period of time, so there is a need to be able to follow this and efficiently control the bending angle. It had been.

The present invention has been made in view of the conventional problems as described above.

Hereinafter, this invention will be described with reference to one embodiment.

First, its configuration will be explained.

FIG. 1 is a perspective view of a folding machine to which an embodiment of the present invention is applied.

An imaging device 1 such as a CCD camera is placed on the side of the bending machine 3 so that it can capture the bending angle of the plate material that is the workpiece that is supplied between the upper die 5 and the lower die 7 of the bending machine 3. Place it on the side. The focus is set on the bending angle detection position of the plate material. The imaging light source 9 is provided at an appropriate position where imaging can be made most clearly, for example, at a position opposite the imaging device 1 on the side of the bending machine.

FIG. 2 is a block diagram of the control device of this embodiment.

The amount of information of the signal from the imaging device 1 can be compressed by controlling the sampling timing with the sample timing controller 13, and the signal is converted into a digital signal by the A/D converter 15. The threshold value of the signal level of this digital signal is determined by the variable resistor 17, and the information becomes binary white and black. Here, the switch 19 selects so that the imaging information in the state where the board material has not yet been supplied to the bending machine 3 is sent to the A memory 21, and the imaging information in the state in which the board material has been supplied is sent to the B memory 23.

The information in the A and B memories 21 and 23 is transmitted one byte each to the arithmetic unit 25, and the difference between the two is taken.
It enters the C memory 27. The information in this C memory 27 is
It is sent in parallel to the CPU 43 and serial converter 31.

The serial converter 31 converts the binary signal sent in a byte array into a serial array,
The white level signal is changed to black level by the inverter 33, and the black level signal is sent to the counter 4 without changing.
1 and the number of pixels is counted. counter 41
The count signal from the CPU 43 is sent to the CPU 43 as information indicating the coordinates of the pixel within the image.

On the other hand, the information from the serial converter 31 is
Through the D converter 35 and the video monitor 45,
It is also possible to reproduce an image of only the board material.

Information is transferred from the A and B memories 21 and 23 to the CPU 43 and the serial converter 31 in parallel to reduce transfer time.
1, 23, 27, the arithmetic section 25, and the serial converter 31 are timing-controlled by a clock from a clock generator 29. From imaging by the board imaging device 1 to the CPU 43
The input of the binarized signal to is within 0.3 seconds at maximum.

Next, the operation of this embodiment will be explained.

First, the imaging device 1 takes an image of a state in which the sheet material is not being supplied to the bending machine 3. This image pickup signal is converted into a binary signal (signal indicating white or black) by the variable resistor 17 and stored in the A memory 21 via the switch 19. The contents of this A memory 21 are information for a state in which there is no plate material, that is, for example, only the molds 5 and 7 are set to the black level.

Next, with the plate material placed thereon, the imaging device 1 images it. This imaging signal is converted into a binary signal in the same manner as described above, and is stored in the B memory 23 via the switch 19. This B memory 23
The content is information that sets both the molds 5 and 7 and the plate material to a black level.

Then, the calculation unit 25
Differences are sequentially calculated for each byte of signal contents No. 1 and No. 23. By calculating this difference, the black level binary signal that constitutes the molds 5 and 7 is erased because it is the same level whether or not the plate material is supplied to the molds 5 and 7. be done. Therefore, as the contents of the C memory 27, only the black level binary signal regarding the plate material is stored.
That is, when the contents of this memory 27 are displayed on the video monitor 45, only the board material will be extracted and displayed at a black level.

Figure 3 shows an example of the bending angle detected by the CPU43.
This is a processing flowchart.

In step 100, image information is fetched from the C memory 27. Assume that the image is in a state where the plate material W is bent by an angle α, as shown in FIG. 4, for example. In step 101, the screen pixels are sequentially scanned in the horizontal direction, and in a coordinate system virtually set on the screen (for example, a diameter X-Y coordinate system), the intersection point A (Xa, Ya) of a certain scanning line and the plate material W is found. B
Find (Xb, Yb). Then, in step 102, the scanning line is shifted downward to find a bending point C (Xc, Yc) where the two intersection points converge to one point. In step 103, α=tan ^-1 (IXa-XcI/IYa-YcI) + tan ^-1 (IXb-XcI
/IYb−YcI) to find the bending angle α.

The drive of the bending machine 3 is controlled according to the bending angle α obtained in this way.

Note that the above content is merely an explanation of one embodiment of the present invention, and it goes without saying that the present invention is not limited to this content.

As can be understood from the description of the embodiments above, in short, the present invention provides the following advantages:
an imaging device 1 that detects the bending angle of the sheet material W and images the bending position of the plate material W in the upper and lower molds 5 and 7 provided in the bending machine 3; A memory 21 stores image information obtained when the upper and lower molds 5 and 7 are imaged in a state where the plate material W is not supplied between the upper and lower molds 5 and 7, and the plate material W is supplied between the upper and lower molds 5 and 7. B memory 23 that stores imaging information when an image is taken in the state, and A memory 2 described above.
1 and the image information stored in the B memory 23; C memory 2 to store
7 and the imaging information of the plate W stored in the C memory, the coordinates of the two points A and B in the bent state of the plate W and the coordinates of the bending point C of the plate W are used to determine the position of the plate W. The CPU 43 calculates the bending angle α.

As is clear from the above configuration, the present invention is a technique that attempts to detect the bending angle of the plate material W by imaging the bending position of the plate material W, so the actual bending angle of the plate material W is detected. This makes it possible to detect the bending angle with high accuracy. As described above, when trying to detect the bending angle by capturing an image of the actual bending position of the plate material W, the actual bending position of the plate material W is located between the tip of the upper die 5 and the groove of the lower die 7. Therefore, it becomes difficult to detect the bending point of the plate material W.

Therefore, in the present invention, since the upper and lower molds are removed to obtain imaging information of only the plate material W, the bending angle at the bending position of the plate material W can be detected.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a bending machine, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a processing flowchart of Fig. 2, and Fig. 4 is a workpiece. FIG. 2 is a diagram showing a captured image of FIG. 1... Imaging device, 3... Bending machine, 17... Variable resistor, 21, 23, 27... Memory, 43...
CPU, W... Workpiece.

Claims (1)

[Claims] 1. An imaging device 1 which is a device for detecting the bending angle of the plate material W in the bending machine 3 and images the bending position of the plate material W by the upper and lower molds 5 and 7 provided in the bending machine 3; A memory 21 that stores image information obtained when the upper and lower molds 5 and 7 are imaged in a state where the plate material W is not supplied between the upper and lower molds 5 and 7;
, a B memory 23 that stores imaging information when an image is taken with the plate material W being supplied between the upper and lower molds 5 and 7, and the imaging information stored in the A memory 21 and the B memory 23. a calculation unit 25 that calculates imaging information of the plate material W based on the stored imaging information; a C memory 27 that stores the imaging information of the plate material W as a result of calculation by the calculation unit 25; Based on the imaging information of the plate material W being bent, the bending angle α of the plate material W is calculated from the coordinates of two points A and B in the bent state of the plate material W and the coordinates of the bending point C of the plate material W.
A device for detecting a bending angle of a plate material in a bending machine, comprising: a CPU 43 for determining the angle of bending of a plate material in a bending machine;