SU1260685A1 - Device for measuring parameters of object displacement - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the parameters of displacement, displacement, vibrations and shocks. The aim of the invention is to improve the measurement accuracy by eliminating errors from moving an object in the direction perpendicular to the optical axis of the radiation flux incident on the object. A device containing a monochromatic radiation source, a diaphragm and a phototransducer with registration units in the measuring circuit also has two mirrors installed with the possibility of movement, placed between the source and the beam splitter and at angles ol to the incident radiation (e 45 °); in this plane, the fluxes of radiation on the mirrors are mutually perpendicular. The device also contains a diaphragm, rigidly connected with a position-sensitive photodetector with the two-coordinate movement mechanism, and two differential amplifiers designed. to form compensating signals with the output of a position-sensitive photodetector and transfer them to the moving elements of the mirrors that move the radiation flux, and through amplifiers with Ki 1 / cos ob to the photodetector moving mechanism, which tracks the movement of the speckle pattern before returning it to the original the position at which the signal from the photodetector becomes zero. 1 hp f-ly. 1 cl. (L

Description

one

The invention relates to a measurement technique and can be used to measure the parameters of the movements of vibrations and shocks.

The aim of the invention is to improve the measurement accuracy by eliminating errors from moving an object in the direction perpendicular to the optical axis of the incident

radiation flux object, I

The drawing shows the block diagram of the device.

A device for measuring the motion parameters of an object contains a monochromatic radiation source 1, a beam splitter 2 located along the radiation flux, dividing the radiation flux into three beams, the first diaphragm 3, the inverter 4 and the recording unit 5 are sequentially installed in one radiation beam, in the other - the reference mirror 6, in the third - a translucent plate 7, through which the radiation beam is directed onto the object 8. In addition, the device contains successively installed behind the monochromatic source 1 the focusing system 9, the first mirror 10 with the linear displacement element 11, the second mirror 12 with the linear displacement element 13, the first and second mirrors 10 and 12 being installed at an angle of sat, for example, to the radiation flux incident on them, and the plane of incidence of radiation on the first mirror 10 is perpendicular to the plane of incidence of radiation on the second mirror 12, successively installed along the course of the radiation behind the translucent plate 7, which are rigidly interconnected by the second diaphragm 14 and position-sensitive a photodetector 15, a two-coordinate linear displacement mechanism with elements 16 and 17 designed to move in orthogonal directions in a plane perpendicular to the optical axis of the third radiation beam, two differential amplifiers 18 and 19, whose inputs are connected to the outputs of the position-sensitive photodetector 15, and The outputs are connected to elements 11 and 13 of the linear movement of the first and second mirrors 10 and 12, two amplifiers 20 and 21 with a gain of Kj l / cosoi, input 606852

The ports of which are connected to the outputs of differential amplifiers 18 and 19, and the outputs to elements 16 and 17 of the mechanism of two-coordinate movement 5 of the position-sensitive photodetector 15, and the position-sensitive photodetector 15 is installed with the possibility of rotation around the optical axis of the incident beam

10 radiation.

The device works as follows.

The monochromatic radiation from source 1 passes through the focusing system 9, is reflected by the first mirror 10 and the second mirror 12 and falls on the beam splitter 2. The radiation beam reflected by the beam splitter 2 falls on the reference mirror 6 and is reflected in the opposite direction, the radiation beam passing through the beam splitter 2 passes through the semitransparent plate 7, falls onto object 8, and is reflected by it in the opposite direction25, partially scattered on the roughness of the surface of object 8. Puzzles of radiation reflected from the reference mirror 6 and volume When the object 8 moves, the phase of the radiation reflected from it changes and, therefore, the intensity of the interference pattern on the photoconverter 4 changes, which is converted by it into an electrical signal, the value of which is determined by the monitored the parameter of moving object 8 in the direction of norm 40 to its surface. Part of the radiation reflected and scattered by the object 8 is reflected by the semitransparent plate 7 and falls on the second diaphragm 14 and the position-sensitive.

45 photodetector 15. Since the diameter of the second diaphragm 14, determined from the ratio

d3.) p. (,)

  where f is the focal distance of the focusing system 9; , - distance from object 8

to the translucent plate 7; 5 fj - distance from plate 7

to the second aperture 14; D is the diameter of the radiation beam on

the output of the focusing system 9;

less than the size of one speckle in its plane, then when the object is displaced in a plane perpendicular to the direction of the radiation incident on it, the speckle pattern formed by scattering radiation on the roughness of the object 8 also shifts, which causes the radiation intensity to change position-sensitive photodetector 15. The position-sensitive photodetector 15 is sensitive to the movement of the incident beam on it in two orthogonal directions. Therefore, when moving the speckle pattern, the signals at both outputs of the position-sensitive photodetector 15 change, each of which is sensitive to linear movement of the radiation beam along one of the coordinates. The magnitude of the signals at the outputs of the position-sensitive photodetector 15 depends on the magnitude and direction of displacement of the object 8. These signals are fed to the inputs of differential amplifiers 18 and 19, which amplify the signals and change their phase by 180. From the outputs of the differential amplifiers 18 and 19, the amplified signals that are out of phase with the input signals arrive at the elements 11 and 13 of the linear movement. The signals from the outputs of the differential amplifiers 18 and 19 also go to the amplifiers 20 and 21, the gain of which K ,. l / cosaj, for example, K 1 / cos 45 ° 1.414. Under the influence of signals taken from the outputs of amplifiers 20 and 21, the linear displacement mechanism with elements 16 and 17 moves the position-sensitive photodetector 15 with diaphragm 14 in the direction of displacement of the speckle structure. At the same time, under the influence of signals removed from the differential amplifiers 18 and 19, the elements 11 and 13 of the linear movement move the mirrors 10 and 12, and hence the radiation beam incident on the object 8, parallel to itself. In this case, the radiation beam moves in the direction of movement of the object 8 of the plane, perpendicular to the direction of the radiation incident on it. Since the signals supplied to the elements 16, 17 and 11, 13 are in antiphase with the signals taken from 60685,

of the position-sensitive photodetector 15, then the elements 16 and 17 move the position-sensitive photodetector 15 with the diaphragm 14 in the 5 direction of movement of the speckle structure until it is occupied. its previous position with respect to the speckle structure, while the elements 11 and 13 of the linear movement at this time move 10 mirrors 10 and 12 until the radiation beam incident on the object 8 occupies its previous position on the object 8. Amplifier gain 20 and 21 selected

T5 is equal to K. 1 / COS 45 ° 1.414, based on the fact that the movement of the position-sensitive photodetector 15 is equal to the movement of the beam incident on object 8, and since the value ne20 of the movement of mirrors 10 and 12 is equal to t Cos 45, then the signals supplied to the elements 11 and 13 of the linear movement should be less than the signals

5 supplied to the linear displacement elements 16 and 17 at 1 / cos 45. 1,414 times.

Claims (2)

1. A device for measuring the movement parameters of an object, containing a source of monochromatic radiation, located along the beam of radiation, a splitter for dividing the flow of radiation into three beams, a diaphragm is installed in the first beam of radiation, the phototransducer and a recording unit connected to the phototransducer, in the second a reference mirror, in the third a translucent plate, characterized in that, in order to improve measurement accuracy, it is equipped with successively installed along the radiation flux between the monochromatic radiation source and the beam splitter focusing system, the first mirror with the linear displacement element, the fire mirror with the linear displacement element, the first and second mirrors are set at an angle to the radiation flux and the plane of incidence of the flux from radiation on the first mirror perpendicular to the plane of incidence of the radiation flux on the second mirror, successively installed behind the translucent plate and optically connected with it by the second diaphragm and position-sensitive photodetector, rigidly connected with it and installed with the possibility of linear two-coordinate movement in the plane, perpendicular optical axis of the third beam of radiation, and having a two-coordinate linear displacement mechanism, two differential amplifiers, the inputs of which are connected The outputs for the corresponding outputs of the position-sensitive photodetector, and the outputs for the linear displacement elements of the first and second mirrors, two amplifiers with a factor (gain K 1 / cos (x ;, whose inputs are connected to the outputs of the differential amplifiers, and the outputs to the mechanism two-coordinate movement of the position-sensitive photodetector, 2. A device according to claim 1, in accordance with the fact that the angle oi is 45 °. 18 79 Editor N.Gorvat Compiled by E.Glazkova Tehred L.Oleynik Proofreader 0.Lugov Order 5214/36 Circulation 670 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4