SU1710999A1 - Method of determining the displacements - Google Patents

Abstract

This invention relates to instrumentation engineering, in particular to optical displacement sensors using a moiré effect. The purpose of the invention is to improve the measurement accuracy by determining movements in two directions. As a moire displacement sensor using a helical coil spring 1, in which the ratio of length to outer diameter is selected in the range of 10-15. The sensor is fixed at one end on support 2, and the other on test object 3. Then, moving support 2 and object 3 (for example, moving support 2 from one position to another 2), an elastically curved section is formed in the middle part of spring 1. 2 Il. ,

Description

Fig, 1

This invention relates to instrumentation engineering, in particular to optical displacement sensors using a moiré effect.

A known method for determining displacements, which means that a moire displacement sensor in the form of a helical coil spring with a winding pitch greater than the wire diameter, is fixed at one end on the support, and the other on the test object, register the pattern of moire bands before and after moving the object and the value and sign of the displacements are determined from it.

The disadvantage of the method lies in the fact that it does not allow measuring the linear displacements of the object along the spring axis, as this results in compression of the turns and loss of the moiré pattern. Thus, it is not possible to measure movements in two directions at the same time, which reduces the accuracy of measurements.

The purpose of the invention is to improve the measurement accuracy by determining movements in two directions.

This goal is achieved by the method of determining displacements, which consists in the fact that a moire displacement sensor in the form of a helical coil spring with an increment exceeding the wire diameter is fixed at one end on the support, and the other is recorded on the object under test. before and after the object is moved and according to it, the magnitude and sign of displacements is determined, as a spring a spring is used with a ratio of length to outer diameter from the range (10 - 15), and when fastening, moving the sensor support to In this case, an elastically curved section is formed in the middle of the spring

FIG. 1 shows a diagram of a sensor mounted to the proposed method: in FIG. 2 - moire floor wasps, species A, B, C. D, E.

The method of determining displacements is carried out as follows.

As a moire displacement sensor (Fig. 1}, a helical coil spring 1 is used, in which the ratio of length to outer diameter is selected within 10 - 15. Sensor 1 is fixed at end 2 on support 2, and the other end on test object 3. Then, moving the support 2 and the object 3 (for example, moving the support from position 2 to position 2), an elastically curved section is formed in the middle part of the spring 1. The sensor is monitored from point 4.

The movement of the object 3 causes the formation of oval on the sensor

or C-shaped moire strips on either side of a 5- or Z-shaped zero strip, with the object moving along the spring axis accompanied by an increase in

(movement to support) or decrease (movement from support) of the number of oval or C-shaped moire bands. Moving an object to or from the observer is accompanied by a 5 (2) -shaped position shift.

zero band and a corresponding change in the overall picture of the bands.

Note FIG. 2 shows some pictures of moire stripes, obtained using a full-scale sensor according to the proposed method. A coil spring with a length of 60 mm was used as a sensor. with an outer diameter of 4.2 mm. Photographs (views A, B, C) show that the movement of object 3 along the spring axis, i.e., to the right or left of the observer, causes a uniquely interpretable change in the moire pattern. Species O, E show some patterns of moire strips characteristic of moving an object.

from / to the observer or simultaneously in two directions (indicated by arrows). Similarly, the angular displacements of the object are interpolated.

Tests have shown that with a ratio of lengths and. outer diameters less than 10, the bending stiffness of the springs prevents the formation of an elastically curved section in the middle part of the springs, and the approach of the ends leads to compression of the inter-turn space

and the loss of moire paintings. With a ratio of more than 15, the stiffness of the springs decreases so much that they sag under their own weight, also leading to a decrease in accuracy.

Compared with the base object, the proposed method for determining movements by introducing new elements allows measuring the movement of an object in two directions simultaneously, which improves the measurement accuracy.

Claims (1)

Invention Formula ..- The method of determining displacements, which consists in the fact that a moire displacement sensor, in the form of a helical coil spring with a winding pitch greater than the wire diameter, is fixed at one end to the support and the other to the object under test, register the pattern of the moire band. and the magnitude and sign of displacements are determined from it, so that they are used so that, in order to increase the accuracy, springs with a length ratio 517109996 to the outer diameter from the range (10 - pin with the object, they form in the middle part 15), and when fixing the spring support of the spring, the elastically curved section is formed. VidayAAA