JPH051883B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention can detect the position of a hot metal lump in the width direction even if disturbances such as water or steam block the field of view of the detector. The present invention relates to a method and apparatus for detecting the widthwise position of a metal lump, which enables the width end position of the metal lump to be detected with high accuracy.

[Prior Art] In rolling or continuous processing, precise sheet width control is desired in order to improve product yield. Particularly in the case of hot rolling, the width of the rolled material widens due to the horizontal reduction in the rolling mill.If this is left unaddressed and rolling is repeated, the width of the product sheet will be much larger than the set value, resulting in post-processing. The portion to be cut away due to side trimming, etc. increases, resulting in a decrease in yield.

On the other hand, meandering tends to occur in reverse rolling on a single stand and in tensionless rolling when passing the leading and trailing ends on a continuous stand, so it is necessary to detect the amount of meandering in the rolled material and adjust the left and right roll gaps. . However, with the conventional method of detecting and controlling meandering based on the difference in rolling load, it is possible to detect and control meandering based on the difference in rolling load that occurs when two pieces of the rolled material are bent due to end bending or when rolling irregularly shaped parts at the leading and trailing ends. It was determined that this was a phenomenon, and the reduction level adjustment was disrupted.
On the contrary, there were fatal defects that caused the rolling operation to be interrupted.

Therefore, in recent years, it has become desirable to control the plate width or meandering of heated metal ingots such as hot-rolled materials and continuously cast materials with high precision, and optical methods are being used as a means of detecting the plate width or meandering, etc. A widthwise position detector has been developed. This device is based on the principle shown in FIG.

That is, the rolled material 1 is illuminated by a light projector 2 from below the rolled material 1, and the amount of light received in the portion not shielded by the rolled material 1 is measured by the light receiving section 3 provided above, that is, in the surface direction of the rolled material 1. This is used to detect the board width. The light receiver 3 includes one using a photoelectric element (photodiode), one using a television camera type image pickup tube, etc., and the one using a photoelectric element will be explained below. The principle remains the same even when a television camera type image pickup tube is used. A plurality of photoelectric elements 4 are arranged in a straight line in parallel with the light projector 2 (a "bit" is generally used as a unit of number), and emit an electric signal 6 proportional to the amount of light received from the image focused through the lens 5. By thresholding the amount of received light at a constant level using a predetermined converter, the electrical signal is converted into two types of synchronization signals 7, on and off. Since the focusing distance per 1 bit is determined by the focusing angle 2α (or focusing range L) of the lens 5 and the distance H between the rolled material 1 as the object to be measured and the lens 5, the total number of photoelectric elements is Assuming that W is N bits, the plate width W can be determined by the following formula.

W=L×{N−(N ₁ +N ₂ )}/N = 2Htan2×{N−(N ₁ +N ₂ )}/N ………(i) Therefore, when rolling It is also possible to apply this method to detect meandering of materials, etc., and it has already been implemented in some places, but since the rolled material itself is at a high temperature of around 800°C, especially during hot rolling, the floodlight 2 shown in Fig. 4 has been eliminated. An effective method is to detect the light from the rolled material itself. The principle in this case will be explained with reference to FIG.
are provided, and the light from the rolled material 1 is detected by the light receivers 8 and 9. At the time of detection, the light receiving element 10,
Light is focused for each of the 11 bits, and a voltage proportional to the intensity of the focused light is generated for each bit. For example, if the relationship between the voltage detected by the light receiving element 10 and each bit of the light receiving element 10 is illustrated, the sixth
As shown in the figure, the position where the voltage difference begins to occur is detected as the work side end of the rolled material 1. Note that FIG. 6 is referred to as a video signal. In FIG. 6, ts is the scanning period required to scan all the bits of each of the light receiving elements 10 and 11, and V is a voltage representing the difference in light amount at the width end of the rolled material.

Incidentally, since the temperature generally varies depending on the type of rolled material, a difference occurs in the amount of light entering the light receivers 8 and 9 shown in FIG. 5 depending on the temperature. That is, when the scanning time ts is increased for a hot rolled material, the time for light to enter the light receiving elements 10, 11 becomes longer, and a large amount of weak light emitted from the rolled material and reflected on the roller table etc. is also transmitted to the light receiving elements 10, 11. As a result, as shown in Fig. 7A, the voltage V is applied to the rolled material 1.
It rises suddenly at a position far away from , and the detection accuracy at the width end deteriorates. Conversely, if the scanning time ts is too short, the time for light to enter each bit of the light-receiving elements 10, 11 becomes short, and as a result, the light is not sufficiently received by the light-receiving elements 10, 11, as shown in FIG. so that the voltage V
There is a possibility that the level of the plate width end detection signal will not reach the reference threshold level voltage _VL , and detection will become impossible. Therefore, it is necessary to automatically control the scanning time ts, to keep the amount of light received by the light receiving elements 10 and 11 constant, and to adjust the voltage V as shown in FIG. 7C.

Therefore, the inventor of the present application, for example,
As shown in the specification of No. 77214, when detecting the width end position of a metal lump using a detector composed of a light receiving element group and a lens that receive light emitted from a heated metal lump, the light receiving element is The scanning period is determined from the amount of light received by a light-receiving element near a light-receiving element that generates a voltage at a preset level in the video signal obtained by scanning from the center side toward the width edge, and the detection The light-receiving element of the device is scanned from the center of the metal mass in the width direction at a determined scanning period, and the address of the light-receiving element that generates a voltage at a preset level is determined to accurately position the metal mass in the width direction. We proposed a method and device for detecting this.

[Problems to be Solved by the Invention] However, in the above-described method and device for detecting the position in the width direction of a metal lump, if the field of view of the detector is blocked by a disturbance such as water vapor, water, or oxide scale, There is a problem that the width end position of the metal lump cannot be detected accurately.

The present invention has been made in view of the above-mentioned circumstances, and has an object of making it possible to accurately detect the width end position of a metal lump without being affected by disturbances.

[Means for Solving the Problems] The present invention provides a detector comprising a lens and a group of light receiving elements that receive light emitted from a heated metal lump, and which enables the metal lump to be scanned in the width direction by the light receiving elements. , a comparator that compares and calculates the voltage difference between the detected video signal at a predetermined location and the video signal at the nearest location, and the voltage difference between the current video signal sent from the comparator and the video signal at a point before. A comparator that compares and calculates the voltage difference between the current video signal and the voltage of the current video signal if the absolute value of the current video signal is larger than the absolute value of the voltage difference of the video signal one point before. A memory circuit that stores the address of the light-receiving element where the difference was obtained, and a memory circuit that determines the positive or negative sign of the voltage difference between the current video signal and the voltage difference between the video signal at a point before, and if the sign changes, the memory circuit stores the address of the light receiving element where the difference was obtained. A code discrimination circuit is provided to issue a command to discard an address stored in the circuit.

[Function] Therefore, in the present invention, the light receiving element is scanned in the width direction of the metal block, and the voltage difference of the video signal for each bit is calculated, and the voltage difference of the video signal at the current time and the voltage of the video signal at a point before are calculated. When the absolute value of the voltage difference between the current video signal and the current video signal is greater than the absolute value of the voltage difference between the video signals one point before, the address of the light receiving element from which the current video signal voltage difference was obtained is calculated. is stored, and if a sign change occurs in the sign of the voltage difference between the current video signal and the voltage difference of the video signal one point before, the stored address of the light receiving element is discarded.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

First, the principle of the present invention will be explained with reference to FIGS. 2 and 3. The video signal shown in FIG.
The video signal shown in FIG. 3 is unaffected by disturbances such as water and oxide scale, and the video signal shown in FIG. 3 is affected by disturbances. It was obtained by scanning in the direction at a predetermined scanning period. In addition, the method of scanning and how to adjust the scanning period are explained in the patent application.
Since it is disclosed in the specification of No. 58-238540, the specification of Japanese Patent Application No. 59-77214, etc., the explanation will be omitted.

Now, in Fig. 2, when scanning from the center of the rolled material 1 in the width direction, the voltage of the video signal obtained by the light receiving element closest to the current address is Vi, and the voltage of the video signal obtained by the light receiving element at the current address is Vi. Signal voltage Vi+
1, the voltage difference ΔVi+1=Vi−Vi+1 is sequentially calculated, and the address N _E of the light receiving element at which the voltage difference ΔVi+1 becomes the maximum is determined to be the width end.

By the way, as shown in FIG. 3, for example, when water 12 is placed on the rolled material 1 and the amount of light entering the light receiving element from that part decreases, the voltage of the video signal of the corresponding light receiving element decreases. In this state, rolled material 1
When the width end position of is determined using the method explained in Fig. 2,
Since the portion on which the water 12 is placed is determined as the width end position, a large error will occur in the detection.

In the present invention, in order to prevent this, the sign change of ΔVi+1 obtained by the above calculation is checked at each time point, and when a sign change occurs, the maximum value of ΔVi+1 obtained at that time is discarded. That is, in FIG. 3, when ΔVk+1=Vk-1>0 is determined at the time point i=k+1, if this is larger than the voltage difference ΔV at the width end position, the address Nk+1 is determined to be the width end position. However, at the next i=k+2 time point, ΔVk+2=Vk+1−Vk+2<0, and the sign changes from positive to negative. As can be seen from FIG. 3, such a sign change never occurs at the width end position.

Therefore, when this sign change is detected and occurs, the maximum value of ΔVi+1 up to now is discarded. By doing so, the address corresponding to the width end position of the rolled material on the light receiving element can be determined with high accuracy. Although FIGS. 2 and 3 show the case where the scanning direction is scanned from the center of the rolled material 1 toward the width end, the same applies to the case where the scanning direction is scanned from the width end toward the center. In this case, the voltage difference and ΔVi+1 take the maximum negative value at the width end position. Therefore, in any scanning direction, the position where the maximum absolute value of the voltage difference ΔVi+1 is obtained is the width end position of the rolled material.

Next, a specific example of the present invention will be explained with reference to FIG.

In the figure, A is a video signal obtained by scanning the photoelectric element of the detector in the width direction of the rolled material as disclosed in the above-mentioned specification, and 13 is the image signal of the address currently being scanned for each pulse of the clock pulse C. A comparator 15 is a comparator that compares and calculates the voltage Vi+1 of the video signal obtained by the light receiving element and the voltage Vi of the video signal sent from the shift register 14 and obtained by the light receiving element at the first address. Sent voltage difference ΔVi+1=Vi+1−Vi and shift register 16
Voltage difference ΔVi at one point before sent from
A comparator that performs a comparison operation with Vi-1; 17 is a sign discrimination circuit that determines the sign of the operation result of the comparator 15;
18 is a memory circuit that stores the address of the light receiving element corresponding to the width end position of the rolled material based on the signal from the code discrimination circuit 17; 19 counts the number of clock pulses C and sends the number as an address to the memory circuit 18; It is a counter.

When detecting the width end position of the rolled material, the voltage Vi+1 of the video signal A of the rolled material and the shift register 14 are used.
The voltage of the video signal before the first address stored in
Vi is sent to the comparator 13 every pulse of clock pulse C, and the difference between the two is ΔVi+1=Vi−Vi+
1 and a voltage difference ΔVi+1 is output from the comparator 13 to the comparator 15 and shift register 16. Further, in the shift register 14, the value of the video signal A is updated every pulse of the clock pulse C.

In the comparator 13, the voltage difference ΔVi+1 outputted from the comparator 13 is calculated by comparing the voltage difference ΔVi at the previous point stored in the shift register 16 with ΔVi−ΔVi+1.
The signal is then sent to the sign discrimination circuit 1.
7, and the sign discriminator 17 discriminates whether the output from the comparator 15 is positive or negative. That is, ΔVi+
If 1>ΔVi, the load pulse L is sent from the sign discrimination circuit 17 to the storage circuit 18, and the number of cross pulses C (address N _k ) counted by the counter 19 up to that time is stored in the storage circuit 18. If water, oxide scale, etc. are attached to the rolled material 1 as shown in Fig. 2, the comparator 15
output becomes negative. Then, the sign discrimination circuit 1
Clear path CE is sent from 7 to storage circuit 18,
Discard the stored address _Nk . Through this operation, the address N _E of the light receiving element representing the true width end position of the rolled material remains in the memory circuit 18. In the shift register 16, the value of the voltage difference is updated every pulse of the clock pulse C.

As described above, even if the field of view of the detector is partially blocked by steam, water, etc., or even if water, oxidized scale, etc. remain on the rolled material, the width end portion of the rolled material can be accurately determined.

In the embodiments of the present invention, a case has been described in which the position of the width end of a rolled material is detected, but the present invention is applicable not only to rolled materials but also to any high-temperature metal lump. It goes without saying that it can be configured by a computer or by hardware such as an electronic circuit, and that various other changes can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the method and apparatus for detecting the position in the width direction of a metal lump of the present invention, water vapor, water, oxide scale, etc. can be avoided when measuring the end position of a heated metal lump with an optical detector. This has the excellent effect of eliminating the influence of disturbances that cannot be measured, making it possible to perform highly accurate measurements.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example embodying the method and device for detecting the position in the width direction of a metal lump according to the present invention, and FIGS. An explanatory diagram of the principle, Fig. 4 is an explanatory diagram of the principle of detecting the widthwise position of a material such as a metal lump, Fig. 5 is an explanatory diagram of the principle of detecting the widthwise position of a heated metal lump, Fig. 6 5 is a graph showing the relationship between the signal representing the difference in light amount at the width edge and the scanning time in the case of width direction position detection, and FIG. FIG. 3 is an explanatory diagram showing changes in output signals due to changes in scanning time. In the figure, 13 is a comparator, 14 is a shift register, 1
5 is a comparator, 16 is a shift register, 17 is a sign discrimination circuit, 18 is a storage circuit, and 19 is a counter.

Claims (1)

[Claims] 1. When detecting the width end position of a metal lump using a detector consisting of a group of light receiving elements and a lens that receive light emitted from a heated metal lump, the light receiving element is moved in the width direction of the metal lump. The voltage difference of the video signal for each bit obtained by scanning is calculated, and the voltage difference of the current video signal is compared with the voltage difference of the video signal at a point before, and the voltage difference of the current video signal is calculated. If the absolute value is greater than the absolute value of the voltage difference between the video signals one point in time, the address of the light receiving element from which the current video signal voltage difference was obtained is memorized, and then the same calculation is performed to calculate the voltage difference within several points. The method is characterized in that when a positive or negative sign change occurs in the difference between the voltage difference between the video signals at a point in time and the voltage difference between the video signals at a point before, the stored address of the light receiving element is discarded. A method for detecting the position of a metal lump in the width direction. 2. A detector consisting of a group of light-receiving elements and a lens that receives the light emitted by the heated metal lump, which enables the metal lump to be scanned in the width direction by the light-receiving element, and a video signal of the detected predetermined location and the first location. a comparator that compares and calculates a voltage difference between a previous video signal; a comparator that compares and calculates a voltage difference between a current video signal sent from the comparator and a voltage difference between a video signal at a point before;
a memory circuit that stores the address of the light-receiving element from which the voltage difference of the current video signal was obtained when the absolute value of the voltage difference of the current video signal is larger than the absolute value of the voltage difference of the video signal one time before; A sign discrimination circuit that determines the positive or negative sign of the voltage difference between the current video signal and the voltage difference between the video signal at a point before, and when the sign changes, issues a command to discard the address stored in the storage circuit. A device for detecting a position in the width direction of a metal lump.