SU1585667A2 - Apparatus for measuring vibrating dimensions - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to improve the accuracy of measurement of vibration displacement by adjusting the recorded luminous flux. The optical system forms an image of the working medium of the source in the plane and within the pupil of the lens and creates a uniform illumination in the plane of the masks. The longitudinal component of the vibration displacements is determined by modulating the light flux in the hole formed by the projection of the inclined edge of the wedge mask onto the plane of the radiation cut-off elements and the edges of these elements and converted by the photo recorder into electric current. The lateral movements are determined in several directions when the base plate is rotated. In this case, one of the radiation cut-off elements closes the projection of the inclined edge of the wedge mask and opens the projection of the corresponding forming half-cylinder, the transverse displacements of which modulate the radiation in the slot by an amount slightly higher than the transverse displacements to eliminate to a minimum the linear component that affects the linearity the light characteristic of the photographic recorder, for which the insufficient light flux is compensated for by a third aperture made with an aperture, is formed th two parallel straight segments and curved segments of the two facing protuberances towards each other and the curvature of the selectable ratios given in the description text. 3 il.

Description

The invention relates to a measurement technique and can be used to measure vibro-oscillations.

The purpose of the invention is to increase the accuracy of measuring the vibration displacement by adjusting the adjustable luminous flux.

FIG. 1 shows a diagram of the device; in fig. 2 is a view A of FIG. 1j in FIG. 3 - view B on fi. one .

The device contains an illuminator 1, a condenser 2, the first mask 3, the second mask 4, in the form of a half cylinder, whose base height and radius are equal respectively to the height and base radius of mask 3. Masks 3 and 4 are bonded to object 5 with their bases and with each other so that the plane of the mask is perpendicular to the plane of the cross section of the half cylinder (in Figure 1

J4i

for clarity, shown rotated 90 around a vertical axis). Behind the masks 3 and 4 is the lens 6, which serves to form an enlarged image of the masks 3 and 4. In the image plane of the lens 6, there is a diaphragm 7 with a hole, in which the distance between the edges 8 and 9 (Fig. 2) depends on the X coordinate, the beginning which coincides with the optical axis, and is calculated by the formula;

n

COS arctg; 2L

2 cos arctg Li

where X and y are, respectively, the horizontal and vertical 20 coordinates of the curvature of the upper and lower edges of the orifice of the diaphragm 7 relative to the axes of the coordinates, having a reference to 25 counts at the intersection point of the optical axis with the diaphragm 7; H is the distance between the outer edges of the slots of the cut-off elements; 1 - the maximum length of the working area in the plane of the diaphragm 7;

L is the distance from the center of the exit pupil of the lens to the plane of the diaphragm 7. Behind the diaphragm 7 (Fig. 1) there are coplanar cut-off elements 10 and 11 having slots 12 and 13, 40 which are made parallel to the base of the mask 3. At a distance from the edge of slot 14 (FIG. 3), exceeding the length of the fully open notch, there is a calibration slot 15, the area of which is calculated for the amount of transmitted radiation corresponding to its increase when the object 5 is moved by a known value.

If 4 (x) is a whole function of X, then

F (x) EL cos Expressing the angle oJ

shine

(x) EL

In order to function uniformly, X must be compensated.

f (x) increase in h in

---- - - - i 4 vj-v- yi; H-1 it; l i

The edge 16 is made in parallel with the pattern-50 allows

mask 4. The elements 10 and 11 of the radiation cut-off are equipped with mechanisms 1.7 and 18 for their movement and are set coplanar with each other. Immediately behind the radiation cut-off elements 10 and 11 and diaphragms 19 and 20 sequentially arranged with them are diaphragms 19 and 20 with actuators 21 and 22 and

55

the structure of the rectifying diaphragm complex configuration, coplanar with the element

flow flux, compensating light flux

The device works at once.

Platform 27 is oriented to an object with a whole, in which

a diffuser 23 that serves to scatter the light flux over the entire surface of the photocathode of the photoregistration system 24. Behind the diaphragm 20 there is a folding mirror 25 with an optical viewfinder 26, which serves to align the device before taking measurements. All of the listed elements of the measuring device (except for masks 3 and 4) are fixed on the platform 27. The platform has the ability to rotate around an axis.

The luminous flux f passing through the elementary areas in the image plane can be defined as the product E4S Eh dx, where h is the height of the elementary areas.

If 4 (x) is the luminous flux as a function of X, then

F (x) EL. Expressing the angle oJ through

 Epo-

(x) E Lh o

cos

X

arctg - ..

In order for the function f (x) to remain uniform for all values of X, it is necessary to compensate for the decrease in

f (x) increase in h in cos arctgp times,

LI

---- - - - i 4 vj-v- yi; H-1 it; l i

allows for

a device with a correction diaphragm with an orifice of a complex configuration located coplanar with cut-off elements,

correction of the luminous flux, to compensate for the missing luminous flux, increasing the accuracy of measuring vibration displacements.

The device works as follows.

The platform 27 is oriented relative to the object in order to select the plane in which the vibration displacement is measured so that the optical axis of lens 6 is perpendicular to the plane of mask 3. The constant luminous flux of illuminator 1 is directed to masks 3 and 4. Edges of slots 14 and 16 of elements 10 and 11 cut-offs, using the appropriate mechanisms 17 and 18, move coplanar to the first cut-off element, setting them in such a position that only the vibrating edges of the mask 3 are visible to the optical viewfinder 26 at the moments of their extreme positions, respectively etstvuyuschih minimum luminous flux. The edges of the diaphragms 19 and 20 are set in such a position with the help of the respective actuators 21 and 22 that only the vibrating edges of the mask 3 and the mask 4 forming at the moments of their extreme positions corresponding to the maximum luminous flux are visible. The folding mirror 25 is folded back. After that, the luminous flux of the illuminator 1 is increased so that the output current of the photorepository system 24 is proportional to the magnitude of the vibratory displacements, does not exceed the linearity limit and rubs it out. Then, the device is calibrated by exposing the calibrating slit 15 and the working zone using the mechanism 18, fully closing the edges of the radiation cutting elements 10 and 11: the diaphragms 19 and 20, and fixing the output current. The displacement amount is determined from a comparison of the output currents. When the platform 27 is rotated, it is possible to measure the vibration displacements in other planes, due to the fact that a half-cylinder (mask 4) is fastened with mask 3 (mask 4) and the function of longitudinal mask 4 is performed by forming a half-cylinder. Edges 8 and 9 of diaphragmatic 7 regulate the proportionality of the light flux to the magnitude of displacements, since the less dense radiation flux corresponds to a larger orifice area formed by the projection

15

and b -

1585667

the mask 3, the edge of the diaphragm 9 and the edge 14 of the radiation cut-off element 11. The proportionality is maintained at any position of the mask 3 relative to the optical axis within the working area.

Thus, high linearity reduces the measurement error of vibration displacement.

Claims (1)

Invention Formula A device for measuring vibratory movements in ed. St. N 1185072, from the fact that, in order to improve accuracy, it is equipped with a third diaphragm, located in front of the clipping elements along the radiation path, is coplanar with the clipping elements and made with a hole formed by two parallel straight segments and two curvilinear segments facing convex - t meet each other, and the curvature determined from the ratio H cos arctg Y ± 2 cos arctg 2L L five 0 five where X, y are, respectively, horizontal and vertical coordinates of the curvature of the upper and lower segments relative to the axes of coordinates, having 1x the origin at the point of intersection of the optical axis with the plane of the third diaphragm; the distance between the outer edges of the clipping elements; the maximum length of the working area in the plane of the third diaphragm; the distance from the center of the exit pupil of the lens to the plane of the third diaphragm. H 1 L FIG. 2 Fig.Z