SU1211603A1 - Arrangement for measuring displacements - Google Patents

Abstract

A device for measuring displacements relates to measurement technology and can be used in measuring the amplitude of vibrations of objects, as well as in measuring linear displacements. The purpose of the invention is the measurement accuracy and the provision of measurements of objects with variable brightness - achieved by completing the photo recorder with two-channel and supplying the circuit with a photo-sensor of background illumination. These elements are connected in a differential circuit to operational amplifiers connected at the outputs with a subtractor, and at the inputs with an adder, the output and input of which are interconnected through multipliers and connected to the inputs of operational amplifiers, which are. It allows to compensate for measurement errors associated with changes in the brightness of the background radiation, illumination and reflectance of the object. 2 Il. about about

Description

11211603

refers to the meter re t

This technique can be used to measure linear displacements, as well as to measure the amplitude of vibrations of objects, in particular, 5 objects heated to high temperatures so that the object itself can become a source of radiation.

The aim of the invention is to improve the accuracy and to ensure the measurement of objects with variable brightness.

FIG. 1 shows a diagram of the device; in fig. 2 - arrangement of the mask windows in a plane perpendicular to the axis of the light flux. T5

The device consists of an illuminator 1, which serves to illuminate the object to be monitored 2, located behind the heat shield 3, serves to thermally protect the device, objective 20, which serves to create the required scale, beam splitting element 5, which serves to divide the luminous flux into two , oculators 6 and 7, which serve to focus the image on the apertures 8 and 9 of the mask, having the shape of a triangle, located between the lenses of the lenses, the photoreceivers 10, and

I1, pa: placed at the foci of the oculi - zors 6 and 7 and used to convert the light flux into an electrical signal, a photosensor 12 of background radiation located in the focus of the optical system 1.3, operational jj amplifiers 14 and 15, resistors 16 reverse link z, adder 17, analog multipliers 18 and

19 and subtractor 20.

The inputs of the operational amplifiers 14 o and 15 are connected to differentially connected photodetectors 10 and

II and the photosensor 12, the same inputs through the feedback resistors 16 are connected to the outputs of the multipliers 5 and 18, the operating room outputs

amplifiers 14 and 15 are connected to the inputs of the subtractor 20 and the first inputs of the multipliers 18 and 19, respectively,

Specifically, the second inputs of the factors 18 and 19 are connected to the output of the adder 17s, the inputs of the adder 17 are connected to the outputs of the factors 18 and 19. Information about the amplitude of movement of the object under study 2 is removed from the output of the subtractor 20.

The device works as follows.

The luminous flux of the illuminator Ij reflected from the object under study 2 passes successively through the heat shield 3, the lens 4, the beam-splitting element 5 and, divided into two light fluxes, through the mask openings 8 and 9 enters the photoreceivers 10 and 11, where images 21 are formed ..

With a stationary object 2, the signal from the photodetectors 10 and 11 is equal to

1o Iq. + ocd (kEo-ET) (1) where 1 is the amount of background illumination;

oL is a coefficient proportional to the sensitivity of the photoreceiver and the geometry of the mask window;

S is the height of the front plane of the controlled object 2; k is the reflection coefficient of the object 2; ЕО - illumination, created

illuminator 1; ET illumination, created

thermal heating of the object 2.

When the object 2 being biased is displaced by an amount x, the signal from the photo receivers 10 and 11 is respectively

1 / IT (КЕо + ЕТ) (И-Х), (2)

1g + o (MkEo + Ejd-x), (3) the signal from the output of the photosensor 12 is 2 Iq Then at the inputs of the operational amplifiers 14 and 15 the signal is equal to

i; 1 - icp, (4)

1 g 4-14- (5) Denote the signal at the outputs of the operational amplifiers 14 and 15 through and and U2., And at the outputs of the factors 1 and 19 through W and W, respectively. Then at the output of the adder 17, the signal is W, + W ,, at the output of the multipliers and 19

 (W, (W /

W) Ui Wo) U,

(6)

(7)

From the condition of the balance of operational amplifiers 14 and 15, we have:

II, R - w.

W

 oh oh

(eight)

I2.R is Wj O (9) where R is the feedback resistance. Solving (6) and (7) taking into account (8) and (9) we get the value of the signal at the output of subtractor 20:

- uj

t;

± 1

t I 1

(ten)

Transform (10) with (2) - (5), we get:

UV and 2x.

Thus, in the device, the output signal does not depend on the parameters 1F, 0 (, ($, k, EY, E-J-, but is a function only of the movement of the object under study.

Claims (1)

Invention Formula A device for measuring displacements, containing an illuminator, a mask with holes, a photo-recording system and an information processing unit, from the mask’s versatility is made in the form of two triangles, turned towards each other and symmetrical with respect to the center of the mask. measuring accuracy and providing measurement of objects with variable p-bone, it is equipped with a lens and a sleeping element installed along the reflected light beam in front of the photo-recording system Chick Backlight and the optical system installed in front of it, the mask with holes is made of two autonomous parts, each of which is equipped with an ocular and contains one of the holes; the photo-recording system - in the form of two photodetectors, each of which is installed opposite the corresponding mask hole, the processing unit information in the form of an adder, a reader, two analog multipliers and two operational amplifiers, whose inputs are connected to differentially-connected photodetectors and a photosensor of the background light and through the feedback resistance - with the analogue outputs with a switch, the outputs of the operational amplifiers are connected to the corresponding inputs subtractors and with the first inputs of analog multipliers, the second inputs of which are connected to the output of the adder, whose inputs are connected to the outputs of the corresponding analog inputs. multipliers, the output of the subtractor is the output of the device. FIG. / - VNIIPI Dakaz 34/4 7 SSffiSS oe "1" Lial PPP Patvit rtyiforod, ulitsa Yekroekna 7 4