JPS5836301B2 - Plate shape detection method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for detecting the shape of a plate that accurately and quickly obtains the shape of the plate in the width direction.

Automation of rolling mills has progressed in recent years, and most of the rolling mills newly built today are equipped with AGC systems and computers.

Although the technology for detecting the flatness of the shape in the longitudinal direction of a plate has been considerably advanced, the technology to automatically obtain the flatness of the shape in the width direction of the plate has not yet been established.

One of the reasons why the technology for detecting flatness in the width direction of the plate is not yet complete is that
It is a well-known fact that there is no device for detecting flatness that is of high practical value.

In terms of flatness, the smaller the difference in the relative elongation of the sheet in the width direction, the flatter the sheet, and in order to detect the shape in the width direction of the sheet,
It is necessary to detect the difference in elongation of the plate in the width direction during rolling.

Conventional shape detection methods include applying force to a board to detect sag, and looking at the tension distribution based on the difference in sag.Also, arranging split rolls and installing a load cell for each, pressing the roll against the board. Detect the difference in force with a load cell,
There are various methods such as methods for determining tension distribution, methods for projecting light and observing its reflection and shaking of a virtual image, and methods for determining stress in a plate by the difference in its magnetic permeability.

However, in all conventional methods, the state of tension distribution can be directly determined from the output difference of sensors arranged in the width direction of each sheet. Due to the effects of expansion and coil winding, the statically detected difference signal in the width direction may disappear into noise, making it impossible to perform highly accurate detection.

The present invention has been made with the aim of eliminating the above-mentioned drawbacks of the conventional method.The present invention detects a signal of the amount of displacement induced by the tension distribution of the plate material by a displacement meter arranged in the width direction of the plate material, and each measurement It is characterized by treating the signal at each point in time as one periodic number with one period equal to the width of the plate and performing Fourier series expansion to remove irregular signal components such as mechanical vibrations and electrical noise. be.

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

In FIGS. 1 and 2, 1 is a rolling machine, 2 is a plate whose shape is to be detected, 3 is n pads arranged in the width direction of the plate, 4 is a displacement meter provided in the pad 3, and 5 is a plate material whose shape is to be detected. is a fluid flow, 6 is a valve, 7 is a high-pressure fluid, 8 is a TEFLEC crawl, 9 is a timing circuit for turning on and off the valve 6, and 10 is for collecting signals detected by each displacement meter 4. sampler,
11 is a memory for storing data sent from the sampler 10, 12 is an arithmetic circuit, 13 is a synthesis circuit, 14 is a CRT monitor, 15 is a timing setting signal, and 16 is a shape signal.

When the output signal of the timing circuit 9 sends a valve ON signal to the valve 6, the valve 6 opens and the fluid flow 5 to the pad 3 is caused.
occurs, pressure is generated within the pad 3, and the plate material 2 changes upward.

n displacement meters 4 arranged in the plate width direction, while the valve is on,
The amount of displacement generated in the plate material 2 is detected, a signal is sent to n addresses of the memory 11, and the signals are stored in the n addresses of the memory 11, respectively.

The timing circuit 9 turns the valve 6 on and off intermittently, and when it is on, the sampler 10 located between the displacement meter 4 and the memory 11 is in an open state.

Further, when the valve 6 is off, the sampler 11 is closed.
By the way, since the amount of displacement changes depending on the tension of the plate material 2, that is, the tension of the plate material 2, if the accurate value of each displacement amount is known, the tension distribution of the plate material 2 can be known.

However, it is often difficult to accurately determine the amount of displacement due to mechanical vibrations caused by the progress of the plate.

Focusing on the fact that this type of disturbance occurs irregularly,
This type of noise is removed by the means described below and the amount of displacement is determined.

That is, if each value stored in the memory 11 is used by the arithmetic circuit 12, each frequency component of the plate-shaped signal is determined based on the Fourier series expansion formula, and each obtained harmonic is synthesized by the synthesis circuit 13, A signal based on the shape of the board in the width direction from which noise has been removed is obtained, and this signal is
It may be outputted and displayed on the RT monitor 14, or returned to the automatic shape control device.

Next, the theory on which the above calculation method is based will be explained using mathematical formulas.

As shown in FIG. 3, the displacement meter 4 arranged in the board width direction detects displacement in the vertical direction of the board on which noise is superimposed.

As the plate progresses, each point 11 and 12 in Fig. 4
, 13, 1,..., a displacement signal with superimposed noise is detected, but when these are arranged on the horizontal axis as shown in Figure 5, the plate shape changes rapidly as the plate progresses. Therefore, a periodic waveform whose plate width length corresponds to one cycle can be obtained.

That is, the displacement waveform depending on the plate shape forms a periodic waveform in which the period T is assigned to the plate width length.

Therefore, at each time point ti(i21.2,3,...
The displacement waveform in the board width direction with superimposed noise obtained in .

In the calculation process for obtaining AmI Brn in equation (11), random noise nt, (X) is averaged and removed.

In order to improve accuracy, appropriate operations may be performed, such as performing the calculation over several cycles, or averaging the obtained results over several cycles after performing the calculation over one cycle.

The subscript m in the above equation indicates the order of the cosine wave necessary to approximate the plate shape, but since the plate shape shows a monotonous change in the width direction, m does not need to take a very large value, and is at most 3.
I think it would be fine to finish next.

In the embodiments of the present invention, a case has been described in which force is applied intermittently to the pad using a valve, but it is also possible to apply force to the pad continuously, and this It goes without saying that if it is a seed signal, it can be made into an accurate shape signal by the same arithmetic processing as described above, and that various other changes can be made without departing from the gist of the present invention.

Since the plate shape detection method and device of the present invention have the above-described configuration, (I) it is possible to detect the true signal of the plate shape rather than the signal buried in noise, which is a common drawback of conventional shape detection sensors; This can be easily and reliably obtained by using the Fourier series expansion method.

(If) Conventional shape detection sensors often process signals in the traveling direction of the board and then replace them in the board width direction to detect the shape, which takes time to detect. According to this means, since signal processing is performed by focusing on the board width direction from the beginning, the detection time is shortened.

Various effects can be achieved.

[Brief explanation of drawings]

FIG. 1 is an explanatory perspective view showing a state in which a plurality of pads are arranged in the board width direction in the board shape detection method and device of the present invention, and FIG. 2 is an explanatory diagram of the board shape detection method and device of the present invention. , FIG. 3 is an explanatory diagram of the principle of the plate shape detection method and apparatus of the present invention, and an explanatory diagram of the detected detection signal in the width direction of the plate. FIG. 4 is an explanatory diagram of the principle of the plate shape detection method and apparatus of the present invention. FIG. 5 is an explanatory diagram of the principle of
FIG. 2 is an explanatory diagram of the principle of the plate shape detection method and apparatus of the present invention, and is an explanatory diagram in which detection signals in the plate width direction at each time point are arranged on the horizontal axis. 1...Rolling mill, 2...Plate material, 3...
...Pad, 4...Displacement meter, 6...
Valve, 8... Deflector roll, 9...
Timing circuit, 10... Sampler, 11.
...Memo IJ-, 12... Arithmetic circuit, 1
3... Synthesis circuit, 14... CRT monitor, 15... Timing setting signal, 16...
...It is a shape signal.

Claims (1)

[Scope of Claims] 1. The signal of the amount of displacement induced by the tension distribution of the plate material is detected by a displacement meter arranged in the width direction of the plate, and the signal at each measurement time is detected by one period corresponding to the width of the plate. A plate shape detection method that is characterized by performing Fourier series expansion by treating it as a periodic stroke number and removing irregular signal components such as mechanical vibrations and electrical noise. 2 Pads that are arranged in the width direction of the plate and apply tension to the plate using fluid pressure, a displacement meter that detects the amount of displacement of the plate, a memory that holds a signal of the amount of displacement detected by the displacement meter, and a signal that is sent from the memory. A plate shape detection device characterized by being provided with an arithmetic unit that performs Fourier series expansion based on the received signal, and a synthesis circuit that synthesizes each harmonic signal.