JPH0423721B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for detecting the position in the width direction of a metal ingot in hot rolling equipment, continuous casting equipment, etc.

[Conventional technology]

In rolling or continuous casting processing, precise sheet width control is desired in order to improve product yield. In particular, in the case of hot rolling, the width of the rolled material widens due to the horizontal reduction in the rolling mill, but if rolling is repeated without this, the width of the product sheet will be much larger than the set value, and the later process 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, the difference in rolling load that occurs when rolling two sheets at the end due to end bending of the rolled material or irregularly shaped parts at the leading and trailing ends, etc. This was determined to be a fatal defect, causing the rolling reduction level adjustment to be disrupted and the rolling operation to be interrupted.

Therefore, in recent years, it has become desirable to control the width or meandering of heated metal ingots such as continuous cast materials with high precision, and as a means of detecting the width or meandering of hot-rolled materials, optical A target 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 emitter 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 receiver 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 5 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 7 proportional to the amount of light received from an image focused through a lens 6. By thresholding the amount of received light at a constant level using a predetermined converter, the electric signal is converted into two types of synchronization signals 8: on and off. Since the focusing distance per 1 bit is determined by the focusing angle 2α (or focusing range L) of the lens 6 and the distance H between the rolled material 1 as the object to be measured and the lens 6, 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 = 2Htanα×{N-(N ₁ +N ₂ )}/N... () Therefore, such a strip width detection means can be used for rolling material It is also possible to apply it to meandering detection such as the A method that detects its own light is effective. The principle in this case will be explained with reference to FIG. to be detected. At the time of detection, the light receiving element 11,
Light is focused for each of the 12 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 11 and each bit of the light receiving element 11 is illustrated, the third
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. 3 is referred to as a video signal. In FIG. 3, _ts is the scanning period required to scan all the bits of each of the light receiving elements 11 and 12, and V is the voltage representing the amount of light 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 9 and 10 shown in FIG. 2 depending on the temperature. In other words, when the scanning period t _s is increased for a hot rolled material, the light receiving time of the light receiving elements 11 and 12 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 11 and 12. As a result of the light being received by the rolled material 1, the voltage V increases as shown in FIG.
It rises suddenly at a position far away from , deteriorating the detection accuracy at the width end. On the other hand, if the scanning period is _too short, the time for light to enter each bit of the light receiving elements 11 and 12 will be shortened, and as a result, the light will not be sufficiently received by the light receiving elements 11 and 12, as shown in FIG. As shown in the figure, the level of the voltage V decreases, and the signal for detecting the edge of the strip does not reach the threshold level voltage V _L , which is the reference for determining the edge position of the strip, and there is a risk that detection will become impossible. be. Therefore, it is necessary to automatically control the scanning period _ts , to keep the amount of light received by the light receiving elements 11 and 12 constant, and to adjust the voltage V as shown in Fig. 4C. .

[Problem that the invention seeks to solve]

According to the present invention, when detecting the widthwise position of a hot metal lump, the scanning period is set to an optimal time corresponding to the temperature of the metal lump, and the widthwise position of the metal lump is accurately detected. This was done to solve the problem.

[Means for solving problems]

In the present invention, there is provided a detector comprising a group of light receiving elements and a lens for receiving light emitted from a heated metal lump, and capable of scanning the light receiving elements from the center side of the metal lump in the width direction; a comparator that compares the video signal voltage of the metal block detected by the device with a voltage at a preset level, and outputs a signal when the voltage of the video signal exceeds the voltage at the set level;
a memory circuit that stores the address of the light-receiving element of the detector at that time when a signal from the comparator is received, and a light-receiving element that generates the address sent from the memory circuit and a voltage of the set level; a subtraction circuit that calculates the difference between the address of the address and a neighboring address, and a subtraction circuit that compares the difference between the address of the light receiving element calculated by the subtraction circuit and the number of clock pulses counted at the start of scanning, and calculates the number of clock pulses counted. A comparator provides a command to close a predetermined switch when the difference is greater than the difference between the addresses of the light-receiving elements sent from the sensor, and a sample-hold circuit that holds the video signal voltage of the metal lump when the switch is closed.

Therefore, the detector scans the metal block from the center side toward the width edges, and the scanning period is calculated based on the amount of light received by the light receiving element near the light receiving element that generates a voltage approximately at the middle level of the video signal obtained by the scanning. is determined, and the metal lump is scanned by the detector from the center side toward the width edge at the scanning period determined by the scanning, and the address of the light receiving element that generates a voltage at approximately the intermediate level is determined. The width end position can be detected.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, how to determine the scanning time (scanning period) will be explained with reference to Fig. 5 A and B and Fig. 6 A and B.
A detector with N-bit elements scans the rolled material from the center to the width end for a predetermined scanning time,
When the width direction position of the rolled material is detected, if the address of the element from which the signal of the threshold level voltage V _L was obtained is the N _C address, then the voltage V _T at the N _T address before it is detected, The scanning time is determined from the magnitude of this voltage V _T . For example, in the case of a video signal with a small amount of light as shown in Figure 5 (a), the signal at the edge of the plate is attenuated, and as shown in Figure 5 (b), the voltage V _T before address N _T becomes low, so the scanning time is lengthened. However, in the case of a video signal with a large amount of light as shown in Figure 6 (a), the rise of the signal at the edge of the board is steep, and as shown in Figure 6 (b), the voltage V _T before the N _T address becomes high, so the scanning time decreases. shorten.

Next, to explain the calculation timing of the width direction position of the rolled material using FIG. 7, in the first scanning cycle from the detection start point A, the detection of the N _C address where the threshold level voltage V _L is obtained is performed. In the second scanning period, from the N _C address of the first scanning period.
The voltage V _T before the N _T address is sampled and held, and the N _C address where the threshold level voltage V _L of the second scanning period was obtained is stored again.
The detector is controlled to correspond to the voltage V _T at address N _T obtained in the 4th scanning cycle, the width end position of the rolled material is calculated, and the result B is output, and in the 4th scanning cycle, the 2nd scanning cycle The voltage V _T at the N _T address before the N _C address of the second scan is sampled and held, and the threshold level voltage V _L of the fourth scanning period is obtained.
The N _C address is memorized again, and in the 5th scanning cycle, the detector is controlled so as to correspond to the voltage V _T at the N _T address obtained in the 4th scanning cycle, and the width end position of the rolled material is calculated. B is output, and in the same way, at even-numbered addresses, from the N _C address of the previous scanning period.
Sample and hold the voltage V _T before the N _T address, and set the threshold level voltage V _L of the corresponding scanning cycle.
The obtained N _C address is stored again, and in the odd scan period, the voltage V _T at the N _T address obtained in the previous scan period is stored.
The detector is controlled to correspond to this, the width end position of the rolled material is calculated, and the result is output. After appropriately controlling the scanning period in this way, the position of the threshold level voltage V _L is determined to be the width end of the rolled material.

Note that when performing the above scanning, the scanning direction is from the center side to the width end direction of the rolled material for the following reason. That is, when the rolled material 1 is scanned as shown in FIG. 8B, the video signal becomes, for example, as shown in FIG. When a level change such as X and Y in Figure A occurs, when scanning from the width end side to the center side of the rolled material 1, there is a risk that the first level change X will be determined to be at the plate end. However, by scanning from the center side to the width ends, the influence of the above-mentioned disturbance can be removed.

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

In the figure, 21 is a comparator that compares the rolled material video signal voltage V detected by a detector (not shown) with a set threshold level voltage V _L and outputs a signal when V≧V _L ; is the number of clock pulses _counted at that time according to the signal from the comparator 21.
(N _C address); 23 is a memory circuit in which the clock pulse count N _C stored in the memory circuit 22 is transferred and stored by the enable signal V _I from the detector; 24 is a memory circuit 2;
26 is sent from the subtraction circuit _{24 .}
Compare the count number N _C before _{N T} address from N _C address with the count number sent from counter 27, and the count number at counter 27 is the count number N _C
A comparator capable of outputting a signal when the signal becomes larger than -N _T ; 28 is a switch that closes in response to a command signal from the comparator 26; 29 is a switch 28;
When V T closes, the voltage of the rolled material video signal at that time V _T
30 is a gain, 31 is a V/F conversion circuit that converts the voltage signal into a pulse of the corresponding frequency, 32 is a counter that counts the output pulses of 31, and 33 is a start pulse generation circuit. .

All counters 27 and 3 are activated by the start pulse.
2 is cleared, and at the same time the count of clock pulses with a frequency corresponding to the initial voltage V _O is counted by counter 3.
Started by 2. Further, the video signal voltage V generated in the light receiving element of the detector by the light emitted from the rolled material is outputted to the comparator 21 for each bit, and the comparator compares and calculates V-V _L. When V≧V _L , a signal is output from the comparator 21 to the memory circuit 22, and the count number N _C of clock pulses at that time is stored in the memory circuit 22.

When an enable signal is generated from the detector, the count number N _C is transferred to the storage circuit 23, and at the same time, N _C -N _T is calculated in the subtraction circuit 24, and the sample and hold circuit 29 is placed in a standby state.

When the clock pulse has finished counting the number of light-receiving elements of the detector, a start pulse is generated again, and the comparator 26 compares the clock pulse count with N _{C -NT} , and the clock pulse count becomes N _C -.
When it becomes larger than N _T , the output signal from the comparator 26 closes the switch 28, and the voltage V _T of the video signal at that time is at the address N _T before the address N _C of the light receiving element corresponding to the threshold level voltage V _L. It is held in the sample hold circuit 29 as a video signal. At the same time, the threshold level voltage in this scanning period
The count number N _C corresponding to V _L is obtained in the same manner as described above and stored in the memory circuit 22.

Furthermore, an enable signal V _I is generated from the detector,
A start pulse is generated again, the changeover switch 34 is switched, and counting of clock pulses with a frequency corresponding to the voltage V _T is started.

Thereafter, the above sequence is repeated, but the scanning period of the light receiving element of the detector is controlled according to the voltage V _T when detecting the edge of the width of the rolled material, and the position of the threshold level voltage V _L coincides with the edge of the stride of the rolled material. be judged.
It goes without saying that the value of V _L can be changed as appropriate by adjustment.

In the embodiments of the present invention, the case where the position of the width end of the rolled material is detected has been described, but the present invention is applicable not only to rolled materials but also to any high-temperature metal lump. that various changes may be made without departing from the gist of the present invention;
Of course, etc.

〔Effect of the invention〕

According to the method and apparatus for detecting the widthwise position of a metal lump of the present invention, it is possible to obtain an appropriate video signal of the edge of the rolled material plate, so that the position of the width end of the metal lump can be accurately detected. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of detecting the widthwise position of a material such as a metal lump, Fig. 2 is an explanatory diagram of the principle of detecting the widthwise position of a heated metal lump, and Fig. 3 is an explanatory diagram of the principle of detecting the widthwise position of a material such as a metal lump.
The graph shown in the figure shows the relationship between the signal representing the difference in light amount that occurs at the width edge and the scanning time in the case of width direction position detection. 5A is an explanatory diagram showing the change in the output signal due to a change in the amount of light. FIG.
An explanatory diagram of the signal voltage at a predetermined address sampled and held in the case of the video signal in Figure A, Figure 6A is an explanatory diagram of the video signal in the present invention when the amount of light is large,
Figure 6B is an explanatory diagram of the voltage at a predetermined address sampled and held in the case of the video signal in Figure 6A;
The figure is an explanatory diagram of the calculation timing when scanning a metal lump in the present invention, and Figures 8A and 8B are explanatory diagrams of the reason why the scanning direction of the detector is from the center side of the rolled material to the width end direction in the present invention, FIG. 9 is an explanatory diagram of an embodiment embodying the present invention. In the figure, 21 is a comparator, 22 and 23 are storage circuits, and 2
4 is a subtraction circuit, 26 is a comparator, 27 is a counter,
28 is a switch, 29 is a supply hold circuit, 3
1 is a V/F conversion circuit, 32 is a counter, and 33 is a start pulse generation circuit.

Claims (1)

[Scope of Claims] 1. 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 placed on the center side of the metal lump. The scanning period is determined from the amount of light received by a light-receiving element near the light-receiving element that generates a voltage at a preset level in the video signal obtained by scanning, and The width end position of the metal lump is detected by scanning the light receiving element from the center side of the metal lump in the width direction at a determined scanning period to find the address of the light receiving element that generates a voltage at a preset level. A method for detecting the position in the width direction of a metal lump. 2. A detection means configured by a lens and a light-receiving element group that receives light emitted from the heated metal lump, and capable of scanning from the center side of the metal lump toward the width end;
Comparing means for comparing the video signal voltage of the metal lump detected by the detection means with a voltage at a preset level, and outputting a signal when the video signal voltage exceeds the voltage at the set level; storage means for storing the address of the light-receiving element of the detection means when receiving the signal from the means; and a storage means for storing the address sent from the storage means and the address of the light-receiving element generating the voltage at the set level. A subtracting means for calculating the difference from a neighboring address compares the value obtained by the subtracting means with the clock pulse count counted at the start of scanning, and the clock pulse count is sent from the subtracting means. Comparing means for giving a command to close a predetermined switch when the voltage exceeds a value, sample-holding means for holding the video signal voltage of the metal lump when the switch is closed, and means for changing the scanning period based on the held voltage. A device for detecting a position in the width direction of a metal lump.