SU1114881A1 - Device for measuring object linear displacements - Google Patents

Abstract

A DEVICE FOR MEASURING LINEAR OBJECT DISPLACEMENTS containing a two-beam interferometer with two photoelectric transducers, a moving direction determining unit, a reversible counter, the information and control inputs of which are connected to the outputs of the moving direction determining unit and the first correction unit that has an input connected to the output unit and the first rectifier, which connects to the output unit, and the first correction unit, whose input is connected to the output unit, and the first correction unit, the input connected to the output unit, and the first offset unit, which is connected to the output unit and the first correction unit, whose input is connected to the output unit, connects to the output unit of the displacement direction detection unit, and a first correction unit that is connected to the output unit and connected to the output unit and the first correction unit whose input is connected to the output unit and the first offset unit, whose input is connected to the output unit and the first correction unit, whose input is connected to the output unit and the first correction unit, the input unit connected to the output unit, and the first correction unit, the input unit connected to the output unit. , characterized in that, in order to increase the measurement accuracy, it sleeps & frequency discriminator, the input is It is connected to the information input of a reversible counter, a frequency divider, the information and installation inputs of which are connected respectively to the information and control inputs of the reversible counter, a delay unit whose input is connected to the output of a frequency divider, the second correction block whose input is connected to the output of the second photoelectric converter, (L outputs of correction blocks are connected to the inputs of the block for determining the direction of movement; the control inputs of the correction blocks are connected to the outputs of the -frequency discriminator, frequency divider and delay unit.

Description

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The invention relates to a measurement technique and dp measurements of linear displacements of various objects can be used.

A device for measuring the linear displacements of an object is known, which contains a two-beam interferometer with two photoelectric converters, a unit for determining the direction of displacement and a reversible counter, and for example, the control and control inputs of which are connected to the outputs -; a unit for determining the directions of translation; and an auxiliary interferometer. The device corrects the measurement results by changing the length of the reference arm of the base ir of the terferometer jj.

The drawback of the device is the occurrence of measurement error when changing the value of the constant and variable components of the photocurrent signal taken from photoelectric converters.

The closest to the proposed technical entity is a device for measuring linear displacements of an object, comprising a double-beam interferometer with two photoelectric converters, a moving direction determining unit, a reversible counter, the information and control inputs of which are connected to the moving direction determining unit and the first unit correction, the input of which is connected to the output of the first photovoltaic converter. The device also contains an auxiliary interferometer. In it, the measurement results are corrected when the distance is changed, measure the main arm of the Egerferometer and the refractive index zj.

A disadvantage of the known device is the occurrence of measurement errors when changing the magnitude of the constant and variable components of the photocurrent signal taken from the photoelectric converters, when the radiation power of the coherent light source entering the main interferometer changes, changing the contrast of interference bands, etc.

The purpose of the invention is to improve the measurement accuracy.

This goal is achieved in that a device for measuring linear displacements of an object, comprising a dual-beam interferometer with two photoelectric converters, a block for determining the direction of movement, a reversible counter, information and control inputs which are connected to the outputs of the block for determining the direction of movement and the first correction block whose input is connected with the output of the first photovoltaic converter, equipped with a frequency discriminator;

S input of which is connected to the information input of the reversible counter, frequency divider, information and installation inputs of which are connected respectively to the information and control inputs of the reversible counter, a delay unit whose input is connected to the output of the frequency divider, the second correction unit whose input

5 is connected to the output of the second photovoltaic converter; the outputs of the correction blocks are connected to the inputs of the block for determining the direction of movement, the control inputs of the blocks

0 corrections are connected to the outputs of the frequency discriminator, the frequency divider and the delay unit.

FIG. 1 shows a functional diagram of the device; 2 a functional diagram of the correction block is shown in FIG.

The device contains a two-beam interferometer 1 with two photoelectric converters, consisting of optically coupled coherent radiation source 2, a beam-splitting element 3, a mirror 4 installed in the reference branch, a mirror 5 connected to the object, installed in the measuring branch of the beam-splitting element 6, diaphragm 7, 8 photodetectors 9, 10, correction blocks 11, 12, the inputs of which are connected to photo detectors 9, 10, adder 13, whose inputs are connected to the outputs of correction blocks 11, 12, transmitter 14, which inputs go connected to the outputs of blocks 11

5512 correction blocks 15, 16 correction whose inputs are connected to the outputs of the adder 13 and subtractor 14, block 17 for determining the direction of movement, the inputs of which are connected to the outputs of the blocks 15, 16 correction, reversible counter 18 which is connected to the outputs the unit 17 for determining the direction of the movement, the frequency discriminator 19, the input of which is connected to the information input of the reversing counter 18, the frequency divider 20, the information and installation inputs of which are connected to the information and control moves down counter 18, a delay unit 22 whose input is soy union of a frequency divider output, control inputs of units 11, 12, 15 and 16 are connected to the correction output E of the frequency discriminator 19 frequency divisor 20 and the block 21 delayed ki. Correction blocks 11, 12, 15, and 16 are comprised of constant level components 22 and level support variable level nodes 23. The constant-support node 22 includes an adder 24, amplitude detectors 25, 26 a summator 27, a digital adder 28, a switch 29, a clocked comparison unit 30, a reversible counter 31, a digital-to-analog converter 32 A component 23 of maintaining the variable component includes a multiplier 33, amplitude detectors 34, 35, subtractor 36, digital subtractor 37, switch 38, clocked comparison block 39, reversible counter 40, digital-to-analog converter 41. The device operates as follows. The light beam emitted by the coherent radiation source 2 is divided by the beam-splitting element 3 into two beams — a reference and a measuring beam, which, having reflected from the mirrors 4, 5, interfere with the beam-splitting during the reverse course; the element is divided into two beams by the beam-splitting element 6 and, after passing through the diaphragms 7, 8, they fall on the photoreceivers 9, 10. Signals taken from the photoreceivers 9, 10 shifted relative to each other by 90 are fed to the inputs of the correction blocks 11, 12 the signal of which is fed to the inputs of the adder 13 and subtractor 14 The signals from the outputs of the adder 13 and subtractor 14 are fed to the inputs of correction blocks 15, 16, the code signal of which is fed to the inputs of the block 17 for determining the direction of travel. When moving the mirror 5 associated with the object, the interference fringes formed on the beam-splitting element 5 move, which leads to the appearance of signals at the input of the moving direction determining unit 17. Depending on the sign of the movement of the object, the movement direction determination unit 17 generates a signal of the object movement sign which nocTjTiaeT to the control input of the reversible counter 18, the information input of which receives impulse signals from the output of the movement control determination unit 17, the number of which is related to the magnitude of the linear movement object. The frequency of the signals generated at the output of the direction-determining unit 17 is signaled by the frequency discriminator 19 and is periodically divided into four by a frequency divider 20. When the direction of movement is changed, frequency divider 21 is reset. When a four-pulse counter 18 passes to the input, corresponding to the movement of one interference band, frequency divider 20 generates a signal that triggers correction blocks 11, 12, 15 and 16 that adjust the constant and variable levels. The work of blocks 11, 12, 15 and 16 of the correction is the same. Each of the correction blocks 11, 12, 15, and 16 is a series-connected node 22, 23 for maintaining constant and variable levels. The operation of each of the constant and variable components maintaining nodes 22, 23 is based on analyzing the constant and variable components of the information signal, comparing with the set point and generating a control signal that maintains the constant and variable level constant.

The constant and current state of the wire is given by a constant or mixed current depending on the speed of the object's power, which is determined by the frequency response of the object,

a) Ormaggdio i1 cm drove on the course of correction block 11, goes to DXO; Scmg. (Ator 24, the output signal from which is fed to the input of item 33, the Vcodal signal. From which it signals the output of the 1 1 ko1 block), Reig1.

At low velocities, the object sigp; and 7s move from the output of the adder 24 and multiply 33 w to the amplitude detectors 25, 26, 34 and 35. on the second and the maximum: -;

Sigpa.ly with amp.hung detector 25, 26, 34 and 35 are fed to the inputs. 27 and face 36. pa outputs) 1x a signal is generated, l}) support; alpha1 is a constant and variable value of an information-signal, which, for example, are supplied to clocked blocks 30, 39 comparisons, where they are compared with aoGi voltage.

When a pulse arrives, from a frequency controlled by a frequency selector 20, on one 13 outputs of clocked blocks 30, 39 comparisons and depending on the result of C1) avnsni pulses are generated, nocTjavaiTine and peBepctnjHHe counters 31 40. tn-inputHoii signal

which in the form of a parallel code enters the digital-to-analog converter 32, 41 output signals from which come to the inputs of the adder 24 and multiplier 33, maintaining constant the level of the constant and variable components of the information signal at the outputs of the correction blocks 11, 12, 15 and 16.

At low speeds

of the object frequency discrik 1inator 19 forms a signal that switches the switches 29, 38, and the constant and Glee eemenna component of the information signal of the signal are measured by digital

the adder 28 and the subtractor 37, the output signals from which through the switches 29, 38 are fed to the clocked comparison blocks 30j 39.

Reset Digital Adder 28 and

The reading of step 37 is carried out by the pulse generated by the delay unit 21.

The adder 13 and the subtractor 14 form at the outputs of the square change the information signals when

phase shift of information signals cunMaeNMX from photodetectors 9, 10 to a sensor different from 90. Using the proposed device allows to increase the accuracy of measuring linear displacement of an object by ABtomatic; : regulation of constant and variable sos, informational analogue information

signals at different velocities of the object.

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Claims (1)

DEVICE FOR MEASURING LINEAR MOVEMENTS OF THE OBJECT, containing a two-beam interferometer with two photoelectric converters, a unit for determining the direction of movement, a reversible counter, the information and control inputs of which are connected to the outputs of the unit for determining the direction of movement and the first correction unit, the input of which is connected to the output of the first photoelectric converter, characterized in that, in order to improve the measurement accuracy, it is equipped with a frequency discriminator, the input of which is connected with the information input of the reversible counter, a frequency divider, the information and installation inputs of which are connected respectively to the information and control inputs of the reverse counter, a delay unit, the input of which is connected to the output of the frequency divider, a second correction unit, the input of which is connected to the output of the second photoelectric converter, the outputs of the blocks corrections are connected to the inputs of the unit for determining the direction of movement, the control inputs of the correction units are connected to the outputs of the frequency discriminate and, a frequency divider and delay unit.