RU2603999C1 - Nonlinearity laser meter - Google Patents

Abstract

FIELD: laser engineering.

SUBSTANCE: laser meter can be used for controlling straightness and alignment in production, assembling and installation of large-size products with length up to 100 m and more. Meter has laser, optical system creating stable basic direction by forming circular structure of laser beam and measuring unit with photodetector connected to computer unit. In order to create possibility to measure nonlinearity and alignment simultaneously in several points of extended route optical system is equipped with unit of two optical wedges mounted opposite each other, beam splitter, and measuring system is equipped with base mark with triple prism, and measuring mark consisting of two triple prisms arranged symmetrically relative to reference axis. Laser optical system and photodetector are arranged on one common base.

EFFECT: technical result is increased accuracy and efficiency of measuring of nonlinearity and alignment at large distances.

1 cl, 2 dwg

Description

The invention relates to measuring equipment, in particular to measuring tools for controlling straightness and alignment during installation and assembly of large-sized products on a long route (up to 100 meters or more).

The present invention solves the problem of increasing the accuracy and productivity of measuring the linearity and misalignment, as well as reducing the complexity and cost of the measurement process in inaccessible complex designs of large products.

In well-known straightness measuring instruments: sighting tubes of the PPS-11 type, optical strings of the DP-725 type, instruments of Taylor-Hobson, Keifel-Esser and other accurate measuring tubes, the line of sight of the tube is taken as the base axis. To implement the basic direction, it is necessary to have two marks installed at the extreme points of the base, and the first should not completely overlap the target mark of the second, distant mark.

The classical scheme of combining the sighting axis of the device with the base fixing axis of the mark is the method of successive permutation of the mark. The same mark is alternately set at the extreme points of the base, and alignment is carried out by linear and angular displacements of the sight axis of the device. The accuracy of alignment of the target and base axes is mainly determined by the type of target marks of the brand. Based on the accuracy of the control, they are subject to high requirements of the contrast of the target sign, sufficient illumination, and when monitoring the alignment, to the accuracy of installation, centering relative to the axis of the base direction or the axis of the controlled hole.

The method of rearrangement of marks is inefficient, and its complexity increases with increasing distance of measurement, and the design of marks does not make it possible to simultaneously monitor at several points on the route. Such devices can be used to control the alignment and straightness of only individual elements isolated from a long path.

Another significant drawback of these meters is the need to use two operators in the measurement process, one of which works with the pipe, the other with the brand. Where operating conditions or production conditions do not allow the use of a person to rearrange brands, this device is generally not applicable.

Known beam splitting mark / 1 /, used in sighting tubes with an axicon, which operates in different zones at different distances. The complexity of the operation of combining the sight axis and the base direction is reduced by the use of a beam splitter. However, a sighting tube with such a beam splitting mark can only be used to control straightness. Its use for alignment control is not known, because it is difficult due to the complexity of the design containing a power supply with wires, a light source, a condenser, a beam splitter, projecting an image of a luminous point on the axis of the control hole, which requires alignment of the optical design of the brand and an exact centering device.

The disadvantages of the target tubes listed above reduce the accuracy of measuring the linearity and misalignment. In addition, their use is limited for accurate measurements at distances of more than 10 meters due to a sharp drop in the sensitivity of sighting tubes.

Currently, laser devices are widely used to control the straightness during installation and assembly of large-sized products at large distances.

In the known laser linearity meters (FIXTURLASER LEVEL laser measuring system of a Swedish company, XL-80 laser interferometer of the English company RENISHAW), the basic direction is formed by a laser beam. To implement the basic direction, it is also necessary to have two brands. One mark is rigidly attached and serves to form a reference beam, the other moves and forms a measuring beam of variable length. For the installation of marks along long axes during the measurement process, various installation and fixing devices are used. As a result, the accuracy and performance of measurements is reduced. Compared to sighting tubes, laser linearity meters operate over long distances, but the grades design in these devices, as well as in sighting tubes, makes it impossible to conduct monitoring at several points on the route simultaneously. Determination of deviations from straightness is carried out by installing a receiver or measuring mark at several points of the object being monitored and measuring their deviations from the axis specified by the laser radiation. Such devices can be used to control the straightness of only individual elements isolated from a long path. In addition, the descriptions of these laser linearity meters do not mention that they are designed to control alignment.

In the present invention, the above disadvantages are absent and the task of improving the accuracy and productivity of measuring the linearity and misalignment is solved, it becomes possible to measure in inaccessible structures without the need for the presence of an observer, the measurement process is simplified.

Closer in technical essence to the present invention is a Laser straightness meter / 3 /, which is a precision measuring device designed to control the shape and relative position of the surfaces of large-sized products at all stages of their manufacture, installation, marking, assembly and operation.

It contains a laser, an optical system that creates a stable base direction by forming an annular structure of the laser beam, and a measuring unit with a photodetector connected to the computing unit. In contrast to the known laser linearity meters mentioned above, the device solved the problem of reducing the measurement error due to the instability of the axis of the laser radiation pattern, but, like all the linearity meters considered above, it is not possible to simultaneously monitor at several points on the path. Moving a brand or receiver along a controlled track is required.

A distinctive feature of the invention is that the optical system that creates a stable base direction by forming an annular structure of the laser beam of rays, in order to create the ability to measure the straightness and coaxiality at several points of the long path to increase accuracy, performance and simplify the measurement process, is supplemented by a node of two optical wedges mounted towards each other and a beam splitter, and the measuring unit is supplemented by a base mark with tripelprizmoy minutes, and measuring mark, consisting of two tripelprizm disposed symmetrically relative to the reference axis. In this case, the laser, the optical system and the photodetector are placed on one common base.

In FIG. 1 is a schematic diagram of the alleged invention — a Laser meter of linearity, where 1 is a laser; 2 - optical system for converting laser radiation; 3 - a beam splitter; 4 - block optical wedges; 5 - basic mark - tripelprism; 6 is a measuring mark with two triple prisms symmetrically located relative to the base axis; 7 - a digital camera with a photodetector; 8 - computing unit; 9 - information display unit (computer).

The device operates as follows.

After the interference conversion of the optical system 2 into a stable base of large extent in the form of an annular structure with a central bright spot, the laser beam, after passing through the beam splitter 3, is sent to the base mark - tripelprism 5 installed at the end point of the controlled object. After reflection from the base mark, the image of the ring structure of the laser beam is projected by the beam splitter 3 into the plane of the photodetector of the digital camera 7. The digital camera converts the signals of the receiver into a digital video signal and transfers it to the computing unit 8. The latter transmits the signals to the information display unit 9, which displays the image of the ring structure on your screen, (on the display screen of the device or on a computer). In FIG. Figure 2 shows the image of the ring structure of the laser beam reflected from the base mark, which is installed in the center of the crosshairs of the computer and taken for the zero position with coordinates X ₀ and Y ₀ .

и угол направления вектора несоосности - «φ», который определяется по формуле.Then include the node of the wedges 4, which consists of two optical wedges mounted towards each other. Measuring mark 6 contains two triple prisms P ₁ and P ₂ located symmetrically with respect to the axis at a certain distance from each other. The node of the wedges 4 occupies two positions. In position "a", the laser beam passing through the node of the wedges falls on the triple prism P ₁ . After reflection from tripelprism P _{1, the} laser beam again passes through the wedge assembly, the beam splitter 3, enters the receiver, into the computing unit. On the computer screen, an image of the ring structure of the laser beam obtained by reflection from the tripel prism P _{1 of the} measuring mark is observed, and the position coordinates of this image X ₁ and Y ₁ are measured, which are stored in the computer memory. The wedge assembly is rotated 180 ° to position “b”. In this case, the laser beam passing through the node of the wedges deviates from the axis and falls on the triple prism P ₂ . The image of the ring structure of the laser beam reflected from tripelprism P ₂ is observed on a computer screen and the position coordinates of the image X ₂ and Y ₂ are measured, which are also stored in the computer memory. According to the measurement results X ₁ , Y ₁ and X ₂ , Y ₂ using a computer to determine the offset of the center of the measuring mark from the axis and the deviation from alignment relative to the base mark with coordinates X ₀ and Y ₀ . Moreover, according to the developed program, the computer calculates the absolute value of the misalignment vector, $$L_{\mathrm{one}}=\sqrt{\delta X_{\mathrm{one}}^2+\delta Y_{\mathrm{one}}^2}$$

and the direction angle of the misalignment vector is “φ”, which is determined by the formula.

, где $$\delta X_1=\frac{1}{2}\left(X_2-X_1\right)$$

, $$\delta Y_1=\frac{1}{2}\left(Y_2-Y_1\right)$$

. $$tg\varphi =\frac{\delta Y_{\mathrm{one}}}{\delta X_{\mathrm{one}}}$$

where $$\delta X_{\mathrm{one}}=\frac{\mathrm{one}}{2}\left(X_2-X_{\mathrm{one}}\right)$$

, $$\delta Y_{\mathrm{one}}=\frac{\mathrm{one}}{2}\left(Y_2-Y_{\mathrm{one}}\right)$$

.

As can be seen from the description of the circuit diagram and operation of the device, on the computer screen you can observe the image of the base mark located on the axis, and the images from the marks offset from the axis — triple prism, and measure the position of the base mark and the position of the center of the measuring mark relative to the base axis moving during the measurement along the measuring line neither the measuring mark nor the receiver and without changing the position of the device. Technical effect: improving the accuracy and productivity of measurements, simplifying the measurement process.

An important distinctive advantage of the proposed straightness meter is the lack of the need for accurate installation of the measuring mark on the axis of the basic direction of radiation or, in the case of misalignment, for accurate installation on the axis of the controlled hole. Why in the known meters of directness use special centering devices.

In the proposed invention, due to the joint use of the distinguishing features: the node of the optical wedges and the measuring mark, consisting of two triples, installed symmetrically to the base axis, the position of the center of the measuring mark relative to the base axis is determined automatically by the computer from two measurements of coordinates X ₁ , Y ₁ and X ₂ , Y ₂ and no centering devices are required.

The condition for combining the center of the measuring mark with the base axis is the equalities: X ₁ = X ₂ and Y ₁ = Y ₂ .

Another advantage of the proposed invention is the absence of the need for two operators to rearrange the brand or receiver when measuring at long distances and in difficult conditions of installation of measuring grades in the construction of complex large-sized objects. For example, in nuclear engineering: when controlling the accuracy of assembly of multi-ton nodes of a mine with a reactor vessel at a depth of more than 13 meters; in shipbuilding: when punching the axis of shaft shafts, when monitoring the parameters of the internal geometry of the product longer than 20 meters, when monitoring the position of the axis of the product relative to the diametrical and main plane of the ship using basic and measuring marks with automatic reading of measurement information and transmitting it to the software and hardware complex , and in other similar production conditions.

So, due to the presence of the listed distinctive characteristics, the proposed straightness and misalignment meter has important advantages.

Firstly, the Meter allows you to measure the straightness and alignment at the same time at several points of the long path.

Secondly, there is no need for two operators to rearrange the brand or receiver when measuring at long distances and in difficult installation conditions of measuring grades.

Thirdly, there is no need to accurately install the measuring mark or target on the axis of the base direction or on the axis of the hole being monitored.

Technical effect: increasing the accuracy of measurements of the linearity and misalignment at large distances, reducing the complexity and cost of the measurement process.

Information sources

1. Brothers V.P. Mark for control of straightness and alignment to the aiming tube with axicon. Av. St. No. 538219, 08.13.76, p. 84.

2. Pinaev L.V., Leontiev G.V., Butenko L.N., Seregin A.G. Laser straightness meter. Patent of Russia No. 2457434. 2010.

3. Leontiev G.V. Laser straightness meter. - Laser string. Optical Journal, No. 10, 2012

Figure captions:

FIG. 1 - Schematic diagram of a laser meter.

FIG. 2 - The ring structure of the laser beam.

Claims (1)

A laser linearity meter comprising a laser, an optical system that creates a stable base direction by forming a ring structure of the laser beam, and a measuring unit with a photodetector connected to the computing unit, characterized in that the optical system is supplemented by a node of two optical wedges mounted towards each other and a beam splitter, and the measuring unit is supplemented with a base mark with triple prism and a measuring mark consisting of two triple prisms located symmetrically relative to itelno base axis, the laser optical system and the photodetector are placed on a common base.

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