SU847025A1 - Photoelectric device for measuring non-planeness - Google Patents

Description

(54) PHOTOELECTRIC DEVICE FOR MEASUREMENT

FLATNESS

one

The invention relates to a measurement technique and can be used, for example, in a rolling mill to control waviness and warping.

A photoelectric device for measuring the flatness of steel tapes and strips is known, comprising a source, lights, a television camera, a video amplifier, a measuring pulse former, an electronic circuit and based on determining the inclination of the strip surface (or tape) by shifting specularly reflected images, for example, an image of a light source elongated forms (tube lamp with a slit diaphragm). When the band is corrupted, the image of the light source is correspondingly distorted, which causes a change in the time intervals between the measuring pulses produced by the multi-channel electronic circuit associated with the television killer output tl

The disadvantages of the known device are low measurement accuracy and limited scope. These drawbacks are due mainly to the diffusion nature of the field or the reflection of controlled strip materials.

The closest to this solution to the technical essence and the achieved result is the measurement by the method of optical triangulation. A photoelectric device for measuring the flatness of a material, such as a strip, made according to the scheme

10 a dual microscope and containing a projection system, a receiving lens, a scanning system with a photodetector, a measuring pulse former and an electronic measuring unit. AT

15 with a lime device, the projection system projects a light spot in the form of a dot or a narrow strip onto the surface of a controlled strip at an angle to the vertical plane. To determine the flatness across the entire width of the object (band), several such devices are used simultaneously. (measuring kangshov) installed in a row across the strip 12.

25

The presence of several channels makes the device very complex and does not allow for ensuring a sufficiently high radiation capacity of the device.

thirty

The purpose of the invention is to increase the resolution of the device. This goal is achieved by the fact that the device is equipped with a linear raster installed in the object plane of the projection system so that its lines are oriented parallel to the edges of the material and the pulse distributor connected between the measuring pulse generator and the electronic measuring unit with a number of channels equal to the number of measurement points.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 is one of the embodiments of the projection and scanning systems; in fig. 3 is one of the variants of the pulse distributor circuit,

The device contains a projection system 1, which includes the source 2 of light and a linear raster 3 installed in the object plane of the projection system 1. The raster lines 3 are parallel to the edges of the controlled strip 4. The projection system 1 is located on the side of the roller table along which the strip 4, C moves The opposite side of the roller table is equipped with a lens 5 and a scanning system 6 with a photodetector. The scanning plane of the scanning system 6 is aligned with the plane of the images of the lens 5. The electrical output of the scanning system 1 "6 6 is connected to the input of the imaging unit 7 measuring pulses, the output of the imaging unit 7 is connected to the input of the distributor 8 pulses, and the outputs of the distributor 8 - with the inputs of the multi-channel electronic measuring unit 9 The number of outputs of the distributor and the channels of the electronic measuring unit 9 is equal to the number of measurement points.

The device works as follows.

Projection system 1 projects onto the surface of a controlled strip 4 linear raster 3 in the form of alternating light and dark strips (lines) parallel to the edges of strip 4. The image field of projection system 1 covers the measurement zone including the entire width of the controlled bands and possible limits of transverse oscillations of the strip measurement process. Lens 5 depicts the surface of the strip 4 with the raster 3 lines in the scanning plane of the scanning system 6. The scanning direction is perpendicular to the raster line 3. The scanning system 6 converts the spatial sequence of the raster lines 3 into a temporal pulse sequence The imaging unit 7 measuring pulses from the impulses forming as a result of scanning

images of raster 3, measuring pulses. The pulse distributor 8 distributes these pulses through the channels of the electronic measuring unit 9. To reduce the number of channels, not all measuring pulses can be used, but through one or two, etc. With outputs wiring. The pulley 8 is fed to the inputs of the multichannel electronic measuring unit 9.

If waviness or warping is formed on some sections of strip 4, then these sections are shifted relative to the reference plane corresponding to the flat strip located (5th in the middle position. This causes a shift of the raster 3 lines in these sections and a corresponding shift in time of the measuring pulses. electronic measuring

0, block 9 measures the temporal shift of the measuring pulses and the magnitude of this shift, taking into account the parameters of the optical system, the indicators of the flatness of the strip are determined

5 for each point through which the raster line passes.

in the embodiment of the design of the projection and scanning systems (Fig. 2), a shadow method is used for projection of the raster, which is simple and reliable. The projection system consists of 5 linear sources of light 2, installed on the side of the roller table, along which the controlled strip 4 moves, parallel to its edges. The raster 3 is made in the form of a multi-gap mask and is installed between the light source 2 and the strip 4. The raster slits are parallel to the light source 2.

The scanning system is made in the form of a cylindrical drum 10 mounted on the shaft of the electric motor 11. On the cylindrical surface of the drum 10 there are slots parallel to the axis of the drum. When the drum 10 rotates, its slit, moving along the image of a strip with raster lines, alternately intersects all the lines. At the moments of intersection, pulses are formed on the photodetector of the scanning system 6, the time sequence of which corresponds to the location of the image raster in the scanning plane.

In the embodiment of the pulse distributor for a raster consisting of 32 lines and a 1b-channel electronic measuring unit (Fig. 3), not all measuring pulses are used, but through one (even) ones. The distributor consists of a serially connected counting trigger 12, a four-bit binary counter 13 and a decoder 14 of a binary code.

The measuring pulses are fed to the input of the counting trigger 12, divides T c into two, after which even pulses are fed to the input of the counter 13. As a result of counting the measuring pulses, the counter 13 records the code corresponding to the number of the measuring pulse. This code from the outputs of the counter 13 is fed to the inputs of the decoder 14 and causes a signal to appear on that of its sixteen outputs, the number of which corresponds to the code on the inputs, therefore, the number of the measuring pulse.

The trigger 12 and the counter 13 are reset to zero at the beginning of each scan period by special reference pulses that are generated by the scanner system.

Thus, the measuring pulses are distributed to the outputs of the decoder in accordance with their sequence numbers (taking into account the division by 2).

In the proposed device, the number of measurement points can be quite large due to the choice of the corresponding line pattern and channels of the electronic measuring unit, i.e. no need to use multiple devices at the same time.

Claims (2)

1. Rgoe. - Int. Cont. Scl. and 25 Technol. Iron and Steel. Tokyo, 1970, Part 2. 2. The patent of France 2308908, cl. G 01 B 11/30, 1976 (prototype). // and fOfMupoSame / ifl will measure. pulses W cuemeNtt I four§