JPS5813841B2 - How to measure the amount of movement of an object - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for measuring the amount of movement of a moving object, such as speed and length, in a non-contact manner and with high precision.

It is industrially essential to measure the amount of movement, such as speed and length, of moving objects, such as steel plates, steel wires, and electric wires, with high precision. Therefore, it is often necessary to measure the amount of movement without contact.

Therefore, by irradiating a moving object with a thousand lines of light, the shadow of the moving object is projected onto a ground glass plate surface, and an image is formed on a grid-like photocell through a lens system, and the movement of this image is converted into an electrical signal. ,
The applicant of the present application has proposed a method of measuring the length of a moving object by calculating the frequency of the output signal using a signal processing circuit (Japanese Patent Application No. 59534/1982).

To describe this method in more detail, as shown in FIGS. 1 and 2, a light source 6 that irradiates parallel light α from a direction perpendicular to the moving object 1 is arranged, and a ground glass shape is placed on the extension line of the irradiation direction of this light source 6. The optical media 7 and the spatial filter 4 are arranged in this order.

The ground glass-like optical medium 7 is made of a plate made of quartz glass, plastic, etc., which has been made into a ground glass state by surface processing, and the spatial filter 4 uses a slit-like photovoltaic cell as a moving object. They are arranged so as to face each other in the direction of movement of the first one.

The light source 6 may be one that reflects the light from the light emitter onto a concave mirror, or one that emits the light from the light emitter in parallel using an optical system that has a slit plate placed at the focal length of two lenses. May be used.

Further, although the upper end portion of the moving object 1 is irradiated with the parallel light α of the light source 6, it is of course possible to irradiate the lower end portion of the moving object 1 or both.

Further, it is not necessary to irradiate the moving object 1 with parallel light from a direction perpendicular to the moving object 1; it is sufficient that the parallel light intersects the moving object 1.

A moving object 1 is irradiated with parallel light α to project the silhouette of the moving object 1 onto an optical medium 7, and the projected image on the optical medium 7 is projected onto a spatial filter 4 through a lens 2.

Therefore, even if the distance between the moving object 1 and the lens 2 is not kept constant because the moving object 1 vibrates or the moving object 1 has no continuity in shape, size, etc. ,
The projected image on the optical medium 7 has a size that matches the size of the moving object 1 because it is produced by irradiation with parallel light.

Therefore, if the distance L1 between the optical medium 7 and the lens 2 is always maintained in a constant relationship, the magnification of the lens 2 with respect to the moving object 1 will always be constant.

Moreover, since the line representing the shape of the projected image on the optical medium 7 has a change in light intensity corresponding to the surface unevenness of the moving object 1, the projected image on the optical medium 7 is projected onto the spatial filter 4 through the lens 2,
The spatial filter 4 outputs an electrical signal having a frequency corresponding to the surface unevenness of the moving object 10, and the frequency of the output signal of the spatial filter 4 is determined by a signal processing circuit as shown in the block diagram of FIG. By integrating,
The amount of movement of the moving object 1 can be measured.

However, in the signal processing circuit shown in FIG.
When the signal is applied to the center frequency estimating circuit 4b through the signal a, the center frequency estimating circuit 4b detects the center frequency using, for example, an autocorrelation coefficient.

The frequency thus detected is converted into length pulses by the scale factor circuit 4c, and the pulses are counted by the counter 4d, thereby measuring the amount of movement of the object.

The above proposal can measure with high precision when the surface of a moving object has minute irregularities, but it is difficult to measure when the moving object has a smooth surface covered with polyethylene, vinyl chloride, or aluminum pipe, for example. It has been found that it is not possible to obtain a clear electrical signal and therefore it is not possible to measure accurately.

Therefore, the inventors focused on the fact that with the parallel light method proposed earlier, it was possible to accurately measure a moving object with a rough surface by obtaining an electric signal. The object of the present invention is to provide a method for measuring the amount of movement of an object according to the claims, in which the surface is roughened to make it easier to obtain a signal.

Embodiments of the present invention will be described in detail based on drawings showing embodiments of the present invention. As shown in FIGS. 4A, 4B, and 5, and FIG. The shadow formed on the medium 7 is imaged through the lens 2 onto the filter 4, which is a lattice-shaped photocell, and the electric signal generated by the movement of this image is generated by the tracking pass filter circuit 4a, center as shown in FIG. The frequency estimation circuit 4b, scale factor circuit 4c, and counter 4d count and measure the amount of movement of the object, and the device used in Figures 1, 2, and 3 is used as is, but this In the invention, parallel light α
On the upstream side of the moving object 1, an adhering device 8 for applying powder 9 such as American flour is installed directly above the moving object 1.

The adhesion device 8 has a thin wire mesh 10 installed near the outlet of the powder 6, and allows the powder 9 to fall uniformly onto the surface of the moving object 1 while being vibrated by a pipelator (not shown). After the powder 9 passes through the parallel light α, the powder 9 is sucked up by a suction device (not shown) such as a vacuum cleaner.

In this way, the smooth surface of the moving object 1 is simultaneously roughened and the measurement accuracy is dramatically improved.

Table 1 shows the measuring accuracy when the moving object 1 is an aluminum pipe and the surface is coated with powder (flour was used here) and when no powder is attached. ,
In the embodiment of the present invention, since the signal components are clearly output, the deviation value 'n-1/X = 0. While the average value X is very small at 18 mm, the average value
4.6 What should be 7mm is X=250. OO
There is a large deviation from m7IL, and the deviation value σn −
1/X is also extremely large and unevenly distributed at 65.80 mm.

This is because the output waveform inevitably contains many noise components in order to increase sensitivity.

Note that instead of the powder 90, a relatively high viscosity viscous substance 11 such as grease may be applied to the moving object 1 via the roller 12, and the surface tension will not result in a smooth surface when the parallel light α is passed through. It is fine as long as it is something.

Further, it is preferable to wipe off the viscous material 11 after passing the parallel light α.

As explained above, the measurement method of the present invention projects a silhouette of the moving object onto an optical medium such as ground glass by irradiating parallel light onto a moving object with a roughened smooth surface. The projected image generated on the target medium is projected onto a spatial filter, the spatial filter outputs an electrical signal having a frequency corresponding to the amount of incident light, and the frequency of the output signal is integrated by a signal processing circuit to determine the amount of movement of the moving object. Therefore, even if the moving object vibrates or has no continuity in shape, size, etc., the magnification of the lens will always be constant for the moving object. It is something that can be done.

In addition, the surface of the moving object measured by the parallel light method is not roughened itself, but the surface of the moving object is temporarily roughened using powder or viscous material, so the surface of the moving object is not roughened. This method can temporarily roughen the surface of a moving object very easily without reducing the quality of the surface of the moving object, dramatically improving measurement accuracy, and the effect obtained by this is extremely large.

[Brief explanation of drawings]

Figures 1, 2 and 3 are explanatory diagrams of conventional measurement methods;
FIGS. 4A, 4B and 5C are explanatory diagrams of a measuring method according to an embodiment of the present invention. In the figure, the numbers used are 1 for the moving object, 2 for the lens, and 4 for the moving object.
is a spatial filter, 6 is a light source, 7 is an optical medium, 8 is an adhesion device, 9 is a powder, and 11 is a viscous material.

Claims (1)

[Claims] 1. A moving object having a smooth surface with a rough surface is irradiated with a thousand lines of light, the silhouette of the moving object is projected onto a ground glass-like optical medium, and the silhouette of the moving object is projected onto a ground glass-like optical medium. A projected image on an optical medium is projected through an optical system such as a lens onto a spatial filter consisting of an array of slit-shaped photodetecting elements such as photocells in a relationship facing the moving direction of the moving object. A method for measuring the amount of movement of an object, characterized in that a spatial filter outputs an electrical signal having a frequency corresponding to the amount of incident light, and a signal processing circuit integrates the frequency of the output signal to measure the amount of movement of the moving object. . 2. A moving object with a roughened smooth surface is irradiated with a thousand lines of light, and the silhouette of the moving object is magnified by an optical medium such as a cylindrical lens and projected onto an optical medium such as ground glass. Then, the projected image on the ground glass optical medium is transmitted through an optical system such as a lens,
The image is projected onto a spatial filter formed by arranging slit-shaped light detection elements such as photocells in a relationship facing the moving direction of the moving object, and the spatial filter outputs an electrical signal having a frequency corresponding to the amount of incident light, and the output signal is A method for measuring the amount of movement of an object, characterized in that the amount of movement of the moving object is measured by integrating the frequencies of A method for measuring the amount of movement of an object according to item 1 or 2. 4. A method for measuring the amount of movement of an object according to claim 1 or 2, wherein the moving object is coated with a viscous material in the longitudinal direction to make the surface rough.