RU1795279C - Optic-electronic for measuring object displacement - Google Patents

Abstract

Usage: in the construction industry in order to control the accuracy of the installation of building structures on the alignment or plane. The inventive optical-electronic device for determining the displacements of the object contains a radiation source 1, a photodetector 2, a measurement unit 3, a unit for selecting and storing information 4, a rectifier 5, a strobe forming unit 6, an indication unit 7, an integrator 8, two switching units 9 , 10, the frequency divider by two 11. 1-2-9-3-5-6-4-10-8-7, 6-11-10, 11-9.3-4. 2 ill.

Description

With

WITH

The proposed device relates to the field of measurement and control of stationary Physical processes. It is intended to determine the energy center of the laser beam and to determine the displacements relative to it and can be used, for example, in geodesy during field measurements and, in particular, in the construction industry in order to control the accuracy of installation of building structures in alignment or the plane.

An analog device contains a series-connected radiation source, a transmitting medium, a photodetector, a unit for determining the difference and sum, a rectifier, 5 indication units.

However, this device has low accuracy and noise immunity due to the fact that much attention is paid to the controlled deviation of the beam from the nominal position.

random disturbances (interference) occurring due to changes in the density of the transmitting medium, mechanical oscillations of the radiation source, the presence of a systematic error due to imperfect functioning of the device units, etc., which naturally negatively affects the accuracy and noise immunity of the measurements. .

An analogue is also a stationary laser automated system for observing the displacements of the test engineering structures,

This device comprises an emitter optically coupled to a photodetector. The receiver contains an integrator and an indication unit. However, this device has low reliability and small functionality.

Optoelectronic device for detecting object displacements - prototype model VI

SQ

holds a radiation source, a transmitting medium, a photodetector, a measurement unit, a rectifier, a strobe shaping unit, a signal sampling and storage unit, an integrator, an indication unit. The output of the measurement unit is connected to the second input of the signal sampling and storage unit.

However, this device does not provide the accuracy of measuring the deviation of the displacements of the object. .

This can be explained as follows;

Blocks 3-8 process the analog signal and, therefore, can be implemented based on, for example, operational amplifiers, transistors, etc. In the signals at the outputs of such cascades, and therefore in the signals at the outputs of blocks 2-8, there is a static bias voltage due to the imperfect elements, and slowly changing due to aging of the elements or when the climatic conditions change, the presence of such a static bias voltage leads an error in assessing the true position of the object (photodetector) relative to the laser beam, which, in turn, may ultimately lead, for example, to a decrease in the quality of construction.

The purpose of the invention is to increase reliability.

The goal is achieved due to the fact that the optical-electronic device for determining the displacement of the object, containing a radiation source, optically coupled to a photodetector, the outputs of which are connected to the corresponding inputs of the measurement unit, the output of the latter is connected to the first input of the block of sampling and storage of information and to its second an input through a series-connected rectifier and a block of gate formations, and the output of a block for selecting and storing information is connected to the input of the display unit through an integrator, equipped with an hour divider Ota, whose input is connected to the output strobe generating unit, connected to a photodetector measuring unit and the sample unit, and an information storage connected to the integrator input respectively through the first and second switching units, the control inputs of which are connected to the output of the frequency divider.

Fig. 1 is a structural electrical diagram of an optoelectronic device for detecting object displacements; figure 2 - structural electrical circuit of the switching unit.

An optoelectronic device for determining the displacement of an object comprises a radiation source 1 optically coupled to a photodetector 2, the outputs of which

connected to the corresponding inputs of the block 3 measurements, the output of the latter is connected to the first input of the block 4 of sampling and storing information and with its second input through series-connected

0 rectifier 5 and strobe forming unit 6, and the output of information retrieval and storage unit 4 is connected to indication input 7 through integrator 8. The first and second blocks 9 and 10 are introduced into the device

5, a frequency divider 11, the input of which is connected to the output of the strobe forming unit 6, the photodetector 2 is connected to the measurement unit 3, and the information sampling and storage unit 4 is connected to an integrator; 8, respectively, through inputted first and second switching units 9 and 10, the control inputs of which are connected to the output of the frequency divider 11.

The device operates as follows.

A beam from a scanning radiation source 1, which can be used as a laser, is transmitted through a transmission medium 8, for example, air, to a photodetector 2. Photo-0 receiver 2 is used to convert the radiation energy into electric current.

If the density of the radiation incident on photodetector 2 is a symmetric function, then the magnitudes of the currents from two

5 current sources of photodetector 2 are equal and their difference is zero. This beam position will be called nominal. When the beam deviates from the nominal position, the current difference becomes nonzero, and the magnitude and sign of this difference determines the degree of deviation of the beam from the center of the photodetector. The indicated difference is determined in the measurement unit 3.

The signal from the output of the measuring unit 3, which determines the magnitude and direction of the beam deflection, is sent to the sampling and storage unit 4, as well as to the rectifier 5, by which, together with the strobe forming unit b, it is determined

0 moment of fixation (reference) of the deviation of the beam. In block 4, the analog signal is constructed from the output of the measurement block 3, and the received voltage of the samples is stored and stored.

5 The moment of the gating of the signal at the output of the measuring unit 3 corresponds to the moment of formation of the signal at the output of the unit 4. When scanning with a beam, this signal has the form of a multi-polarity pulse, the amplitude and polarity of which determines the value and

beam deflection direction. In order to generate a gating pulse, the signal from the output of the measuring unit 3 is rectified in block 5 and, through the strobe forming unit 6, is supplied to the signal sampling and storage unit 4.

A signal recorded in block 4 that displays the current difference due to various interferences, for example, mechanical tremors of the radiation source 1, inhomogeneity of the transmission medium, background charge, etc. has a variance with respect to mathematical expectation. In order to reduce the influence of spurious deviations of the wave (beam displacement vectors on the control accuracy, the signal from the output of the signal sampling and storage unit 4 is averaged in the integrator 8.

Thus, the combination of blocks 5 and b provides, by gating, recording information on the value of the bias of the photodetector 2 relative to the specifying direction of the radiation beam only at the moment of receiving the radiation pulses by the photodetector 2 (and thereby eliminate the component of the measurement error, causing - interference to it at times when no useful information about the offset is received by the photodetector 2), and the combination of blocks 4 and 8 allows you to integrate the values of information pulses stored in block 4 about the offset value (And thereby improve the accuracy by reducing the random component measurements).

The indication of the deviation of the beam is carried out in the display unit 7, it is possible to indicate not only the deviation of the beam from the nominal position, for example, with a pointer device with a zero in the middle of the scale, but also organize an optical signaling of the deviation sign.

From the consideration of the principle of functioning of the proposed device, it follows that, due to processing by blocks 3 and 4, a static systematic error may appear in the signals at the outputs of blocks 3 and 4, which varies depending on the aging of the elements, the influence of climatic conditions, etc. and resulting in a decrease in the accuracy of the bias estimate.

, Ј | to compensate for this static error, the first switching unit 9, periodically performing the signal inversion, is included in the circuit of the signals from the outputs of the photodetector 2 to the measurement unit 3; In order for the introduced inverse of the signal not to lead to an incorrect estimate of the bias, it is necessary

also carry out the inversion of the signal at the input of the integrator 8. This operation is carried out by means of the second switching unit 10.

We show that the introduction of blocks 9 and 10 provide compensation for static errors.

We introduce the following notation: FofrnT) and Fi (mT) are the signal values at the outputs of the photodetector 2 and the first switching unit 9 during scanning. By introducing the first switching unit 9, the signal at the input of the measuring unit 3 Fi (mT) is

Fi (mT) (-1) Gt / n FotmT), 0)

where l is the division coefficient of the frequency divider 11 into two;

m / n - designation of the integer part of the number m / n,

It is easy to show that due to the introduction of the second switching unit 10, the value of the signal Pz (tT) at the input of the integrator 8 is equal to :. , F3 (mT) F2 (mT) - (- 1) fm /;

(

 FiifmT) -a (mT) - (-l / m / n; -1 / m7n -Fo (mT) -afrnT) (-) fm / n

Fo (mT) va (mT)

(2)

where n is the division coefficient of the frequency divider 11,

those. the value of Pz (tT) corresponds to the required (function a (tT) - the form is determined

gated signal).

We show that the statistical error is compensated by means of these transformations.

 Suppose that in the signals at the output of the set of blocks 3 and 4 there is a statistical error A, Then the signal F2 (mT) has the form: F2 (mT) (- 1 / m / n + A, expression (2) is converted to

45 Rz tT) Г F2 (mT) (-1) 1 + AJ х х (-1 / t / 1 F2 (mt) + А (-l / m / nJ Fe (mT) afmT)

(3)

Taking into account that (-1 / m / n) О, then expression (3) goes into (2), which is equivalent to compensating for static error (here ... is the designation of the operation to calculate the mathematical expectation) .: Signal from the output of block 4 Sampling and storage enters the switch 12 directly and to the switch 13 through the inverting amplifier 14.

The control signal from the frequency divider 11 is fed directly to the switch 12 and through the element 15 is NOT to the switch 13. Thus, depending on

The formula of the invention An optical-electronic device for determining the displacements of an object, containing a radiation source optically coupled to a photodetector, the outputs of which are connected to the corresponding inputs of the measurement unit, the output of the latter is connected to the first input of the sample and information storage unit and with its second input through a series-connected rectifier and a strobe forming unit, and the output of the information-sampling and storage unit 2

In the form of the control signal at the output of block 10, the signal is either inverted or not.

is connected to the input of the display unit through an integrator, characterized in that, in order to increase reliability, it

equipped with a frequency divider into two, the input of which is connected to the output of the strobe forming unit, the photodetector is connected to the measurement unit, and the information sampling and storage unit is connected to the integrator

accordingly, through the introduced first and second switching units, the control inputs of which are connected to the output of the frequency divider by two.

(pue.i