JPH03249514A - Flatness measuring instrument - Google Patents

Abstract

PURPOSE:To eliminate the factor of the up-down vibration of a beltlike body and to improve the flatness measurement accuracy by measuring inclination values at respective measurement positions by using twin beam type distance measuring instruments, and calculating flatness such as an elongation percentage from the inclination values. CONSTITUTION:The twin beam type distance measuring instruments 12 are provided above the beltlike body, which moves in a longitudinal direction at a constant speed V, in a transverse direction of the beltlike body. The distance measuring instruments which have fine intervals in the moving direction of the beltlike body irradiate the measurement positions on the surface of the beltlike body with couples of mutually parallel measurement beams and receive their reflected beams to measure respective distances to respective irradiation positions having fine intervals. Their distance signals are inputted to an inclination value arithmetic part in an arithmetic unit 15 and the inclination values at the relevant measurement positions are calculated. The calculated inclination values are inputted to a succeeding elongation percentage arithmetic part 18 and totalized to calculate arc length and the elongation percentage at a specific distance while the influence of the up-down vibration component of the beltlike body 11 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flatness measuring device that measures the flatness of the surface of a strip moving in the longitudinal direction at a plurality of locations in the width direction of the strip.

[Prior Art] In a hot rolling line in a steel mill, an inspection line is used to detect shape defects such as a mid-elongation state in which the center part in the width direction of a rolled product is elongated, and an ear wave state in which the shape of the peripheral part is wavy. A flatness measuring device is installed online to measure the flatness of the surface of a strip-shaped rolled product.

This type of flatness measuring device has been developed to be able to quantitatively detect flatness using various methods. A flatness measuring device for measuring the flatness of a surface has been proposed (Japanese Unexamined Patent Publication No. 178608/1983).

FIG. 6 is a schematic diagram showing a schematic configuration of a flatness measuring device that measures flatness using the method described above. A plurality of distance measuring devices 2 are disposed in the width direction of the strip 1 above the strip 1 that moves at a constant speed V in the longitudinal direction. Each distance measuring device 2
measures the distance Y from the distance Mal determiner 2 to the surface of the strip 1 at regular intervals Δ, and sends each distance signal to the arc length calculator 4 via the next low-pass filter 3. As shown in FIG. 7, the arc length calculator 4 calculates distances Y+ and Y+ at time t and time t1+ after a certain time Δ has elapsed.
++ and the moving distance ΔX+(-V
- From Δt), the length of the surface of the strip 1 at the corresponding distance ΔX, that is, the arc length ΔS, is calculated based on equation (1).

ΔS, -(ΔXI) 2+ (ΔY+)...(1) However, ΔYl-Y, -YI+1 Therefore, when the strip 1 moves by the distance from point a to point b in the longitudinal direction, the distance is The overall arc length S corresponding to is L-(n-1)ΔX1, then (2
) is shown by the formula.

Therefore, the elongation rate β when moving by the distance is defined by equation (3), and is calculated by each elongation rate calculator 5.

β-(S-L)/L ・ (3)
Using the above method, each elongation rate β at each position in the width direction
1 to β distortion can be found.

In addition, in FIG. 6, in order to eliminate the cause of large undulations of the strip 1 from the measured elongated skewer, the arc length SS2. . . , S, the elongation rates β1 to β at each width direction position are calculated using the minimum arc length Syu1o.

β, −(S,, −S,,,) / S mln
-(4) Furthermore, the low-pass filter 3 has a function of removing high-frequency noise components contained in the measured distance signal.

[Problems to be Solved by the Invention] However, even in the flatness measuring device configured as described above, there are still problems as described below that need to be solved.

That is, when using this flatness measuring device to measure the flatness of a rolling strip that is continuously moving on a roller conveyor in a hot rolling line in a steel mill, for example, the flatness of a strip to be measured is Since it constantly moves while vibrating vertically and horizontally, errors caused by this vibration are mixed into the measured flatness. The vibrations that occur with this transportation are not just simple vertical movements, but also complex phenomena such as pruning and shaking, so it is difficult to completely prevent these vibrations. For example, it is impossible to improve the accuracy of measurement of vibration below the amplitude of vertical vibration. Furthermore, since the amplitude of the vertical vibration is usually larger than the height vibration of the strip due to poor flatness, it is difficult to accurately measure the flatness.

Note that it is conceivable to remove the vibration component caused by the vibration contained in the distance signal output from the distance measuring device 2 using, for example, a low-pass filter, but this method can be solved by approximating the period of vertical vibration and the measurement time interval Δt. Therefore, there is a problem in that the moving speed of the strip 1 must be reduced.

The present invention was made in view of these circumstances, and
By determining the inclination value at each measurement position using a twin beam distance measuring device, it is possible to reliably eliminate the cause of vertical vibration of the strip as the object to be measured, greatly improving flatness measurement accuracy. The purpose is to provide a flatness measurement device that can

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a plurality of distance meter measuring devices that measure the distance to the surface of a strip moving in the longitudinal direction in the width direction of the strip. A speed detector is provided to detect the moving speed of the body, and each arc length indicating the surface length of the strip is calculated based on each distance signal and speed signal obtained from each distance measuring device and speed detector. In a flatness measuring device that obtains the flatness of a strip from the arc length, each of the distance M 11PJ fixed machines is irradiated with a pair of mutually parallel measurement beams having a minute interval to a measurement position on the surface of the strip. , consists of a twin beam type distance measuring device that simultaneously measures the distance to each irradiation position with minute intervals at the measurement position on the surface of the strip, and this distance n] to each irradiation position measured by the meter is used. The slope value at the corresponding measurement position is calculated from the distance, and the arc length is calculated from each slope value corresponding to each position in the moving direction of the band-shaped body.

[Operation] First, the reason why vibration factors can be eliminated from the measured flatness by measuring the slope value at an arbitrary measurement position on the strip will be explained.

As shown in Fig. 2, the distance Y to the surface of the strip measured by each distance measuring device arranged in the width direction is basically a function F (X) of the moving position X of the strip. , is also a function of the vibration component B(1) depending on the time t in the vertical direction. Therefore, the distance Y can be expressed as a function of the sum of the two, as shown in equation (5).

Y (X, t) - F (X) + B (t) ...
(5) Here, if we differentiate both sides of equation (5) with respect to the position X, we get
dY (X, t)/dX=dF (X)/dX (6) That is, the right side (dF (X)/dX) of equation (6) indicates the slope value at the corresponding measurement position X on the surface of the strip. Therefore, by measuring the slope value at the corresponding measurement position with each distance measuring device and summing up the slope values at each measurement position, the arc length at a predetermined distance with the influence of the vibration component B (t) removed can be obtained. Therefore, flatness is obtained from this arc length.

In addition, as a means of obtaining inclination values at each measurement position with a distance measuring device, parallel measuring beams with minute intervals are irradiated onto the measurement positions, and the distances to each irradiation position with minute intervals are simultaneously measured. The degree of inclination at the corresponding measurement position is obtained from each distance.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a schematic configuration of a flatness measuring device according to an embodiment. A plurality of twin-beam distance measuring devices 12 are disposed above the strip 1 that moves at a constant speed V in the longitudinal direction and in the width direction of the strip 11.

As shown in FIG. 2, each twin-beam type distance measuring device 12 has measuring beams 12a and 12b composed of parallel, for example, high-frequency modulated laser beams having a minute interval dX in the moving direction of the strip body 1. is irradiated onto the measuring position of the belt-shaped body, and each reflected light reflected from each irradiation position formed at the corresponding irradiation position is received by a light receiver, and each distance Y from this distance measuring device 2 to each irradiation position is determined. , ,Y,2 is measured.

Each pair of distances Y measured by each distance measuring device 12
Each distance signal indicating II+Y, 2 is converted into an optical signal by an electric/optical converter 13, and then returned to the original distance signal by an optical/electrical converter 16 in the arithmetic unit 15 via an optical fiber 14. Each distance signal is input to each of the following slope value calculation sections 17. Each slope value calculation unit 17 calculates a slope value at a corresponding measurement position from each manually inputted distance signal. That is, the measuring beam light 12a in each distance measuring device 12.

Since the minute interval dX of the beam 12b is known, if the difference in distance (Y, -Y, □) to each irradiation position is dY, then the degree of inclination at the corresponding measurement position is (dY/dX).

Each slope (dY/dX) at each width direction position calculated by each slope value calculation section 17 is inputted to the next elongation rate calculation section 18. A counter 19 is also connected to this elongation rate calculating section 18 . 20 The counter 19 receives a pulse signal corresponding to the conveyance speed from a detector 21 that detects the rotational speed of the conveyance roller 20 for moving the strip 1 at a substantially constant speed. The counter 19 counts the number of pulses, and when the count value reaches a certain value, the elongation rate calculation unit 1
8. Sends a trigger signal. In the embodiment, a trigger signal is output when the strip 11 moves in the movement direction by a minute distance dX between the measurement beams 12a and 12b. Therefore, the detector 21 and the counter 19 constitute a speed detector that detects the speed of the strip 1.

Then, the elongation rate calculation unit 18 performs the following calculation to calculate the arc length S and the elongation rate β corresponding to the distance from the position a to the position as shown in FIG.

That is, as shown in Figure 2, if the minute arc length corresponding to the minute distance dX is dS, then the minute arc length dS is dS - (dX) 2 → - (dY) 2 and corresponds to the distance. The arc length S is...(Force and elongation rate are defined as β-(S-L)/L, so substituting equation (7) into this equation gives...(8) When actually calculating the formula, every time a trigger signal is input from the calanta 19, the square value of the slope value (dY/dX) output from the slope value calculation unit 17 is sequentially added starting from position a. Just keep doing it.

Using the above method, each elongation rate β1 to β□ at each position in the width direction of the strip 11 is determined.

Furthermore, since the measurement is actually carried out continuously, the distance is constant, but the positions a and b sequentially move.

As a result, the elongation rate β is continuously output.

The obtained elongation rates β1 to β are transmitted via the output control unit 22 to an external host computer 23. Dusk control device 24,
It is output to the recorder 25, CRT display device 26, etc.

Next, using the flatness measuring device configured as described above, the widthwise direction is measured from channel 1 (CHI) to channel 5 (
FIG. 3 and FIG. 4 show changes in each of the elongation rates β1 to β5 when five distance measuring devices 12 are disposed up to CH3). Figure 3 is a waveform chart output using the recorder 25 to show the temporal changes in elongation rates β and ~β5 at each measurement position in the width direction, and Figure 4 (, a) is a waveform chart in the right side of Figure 3. It is a diagram showing the values of the elongation rate β, ~β, at each axial position (each channel) at the moment when the elongation state is occurring, displayed in real time using a CRT display device 26,
FIG. 4(b) is a diagram showing in real time the values of the elongation rates β1 to β5 at each axial position (each channel) at the moment when the central ear wave state in FIG. 3 is occurring.

Further, FIG. 5 is a diagram showing the correlation between each elongation rate β obtained by increasing the actual value by +111 and the five-level evaluation score when the elongation rate is visually evaluated by a skilled worker. As shown in the figure, it was confirmed that the measurement results had a good correlation with the visual evaluation by an expert.

In this way, the data is recorded on the recorder 25 and the CRT display device 26
By displaying the flatness of the strip 11, the flatness of the strip 11 can be accurately grasped.

In addition, by using a twin beam type distance measuring device as each distance measuring device 12 to calculate the slope value at the measurement position of the surface of the strip 11 that is moving at high speed, the elongation rate is finally calculated. The error component caused by the vibration of the band-shaped body 11 can be completely removed from β. As a result, the elongation rate β
Since it is possible to suppress the measurement accuracy of the flatness represented by the vibration component to below the vibration component, even if the vibration during conveyance of the strip 11 to be measured is about the same as that of the conventional device, Measurement accuracy can be significantly improved compared to other devices.

Incidentally, in the example device, the measurement range of the elongation rate β was as large as 0 to 5%, and the measurement accuracy could be controlled within the measurement range to ±0.2%. In addition, the response characteristic is that the time required to measure one elongation rate β is approximately 100n.
I was able to shorten it to s.

Furthermore, in this embodiment, a pair of measuring beams 12a are output from each distance measuring device 12.

Since the laser beam 12b uses a high frequency modulated laser beam, the radiation noise output from the strip 11 can be removed even if the strip 11 is made of a hot steel plate.

[Effects of the Invention] As explained above, according to the flatness measuring device of the present invention,
The slope value at each measurement position is measured using a twin beam type distance measuring device, and the flatness such as elongation rate is calculated from this slope value.

Therefore, it is possible to reliably eliminate the cause of vertical vibration of the strip-like object to be measured from the calculated flatness, and it is possible to significantly improve the flatness measurement accuracy.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 to 5 show a flatness measuring device according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing the general configuration, and FIG. 2 is a measurement principle. Figures 3 and 4 are characteristic diagrams showing the measured flatness, Figure 5 is a correlation characteristic diagram showing the correlation between actual measured values and visual evaluation, and Figure 6 is a characteristic diagram showing the correlation between measured values and visual evaluation. FIG. 7 is a block diagram showing a conventional flatness measuring device, and is a diagram for explaining the measurement principle in the conventional device. 11... Band-shaped body, 12... Distance measuring device, 17...
Inclination value calculation unit, 18... Elongation rate calculation unit, 19... Counter, 25... Recorder, 26... CRT display device.

Claims (1)

[Scope of Claims] A plurality of distance meter measuring devices for measuring the distance to the surface of the strip-shaped body moving in the longitudinal direction in the width direction of the strip-shaped body and a speed detector for detecting the moving speed of the strip-shaped body are provided, Each arc length indicating the surface length of the strip is calculated based on each distance signal and speed signal obtained from each distance measuring device and speed detector, and the flatness of the strip is obtained from each arc length. In the distance measuring device, each of the distance measuring devices irradiates a measurement position on the surface of the strip with a pair of parallel measurement beams having a minute interval to measure the minute distance at the measurement position on the surface of the strip. It is composed of a twin beam type distance measuring device that simultaneously measures the distance to each irradiation position, and calculates the slope value at the corresponding measurement position from the distance to each irradiation position measured by this distance measuring device. A flatness measuring device, characterized in that the arc length is calculated from each inclination value corresponding to each position in the moving direction of the body.