SU777414A1 - Angular displacement sensor - Google Patents

Description

The invention relates to a measurement technique and can be used to measure small angular displacements of various objects.

A photoelectric autocollimation device is known, comprising an emitter, a lens, a reflecting element, photodetectors, as well as prisms, a modulator,. electronic unit 1.

The operation of the device is based on the alignment of the luminous flux of the radiator reflected by the reflective element and supplied in a differential circuit to the photodetectors by a beam-splitting prism moved with the aid of a tracking system.

The displacement of the prism is judged on the angular displacement of the reflecting element.

Internal light interference is compensated by two additional prisms and two photodetectors connected to the electronic unit.

The closest technical solution to the invention is an angular displacement sensor, comprising a radiator, a diaphragm, a lens, a reflecting element mounted on a controlled object, two photodetectors and an indicator 2. The sensor also contains a power source

radiator, synchronous integrator, divider, phase detector.

The light flux radiating from a reflecting element falls on two 5 photodetectors, by the difference of the voltages at which the magnitude of the angular displacement of the reflecting element is judged.

Amplification of signals from photodetectors is carried out on alternating current by introducing modulation of the light flux by the radiator and subsequent phase-sensitive detection. The initial calibration of the electron path is performed by a divider.

15

A disadvantage of the known devices is the lack of compensation for external light interference, which reduces the accuracy of the measurements. I The purpose of the invention is to improve the accuracy of the measurements.

This is achieved by the fact that the sensor is combined with two controllable luminous flux interrupters, a differential amplifier, an arithmetic unit and a control unit 25, the first interrupter is installed between the reflecting element and the lens, the second between the diaphragm and the lens, the inputs of the differential amplifier are connected to the photodetectors, and

30 output is connected to the arithmetic input

The block whose output is connected to the indicator, the corresponding outputs of the control block are connected to the interrupters and the second input of the arithmetic unit.

The drawing shows a structural diagram of the proposed sensor.

The sensor contains an emitter of L aperture 2, a beam-splitting element 3, a lens 4, a reflecting element 5 mounted on a controlled object, interrupters 6 to 7 of the luminous flux, photodetectors 8, a differential amplifier 9, an arithmetic unit 10, an indicator, a control unit 12.

The sensor works as follows.

The luminous flux of the radiator / diaphragm is set by the diaphragm 2 and when the interrupters are open, 6 w. 7 passes the beam-splitting element 3, the lens 4 and, having reflected from the element 5 in the reverse course, the lens 4 and the beam-splitting element 3 pass through, it gets on the photodetector 8, on which the autocollimation images of the diaphragm 2 are built.

The electrical signals taken from the photodetectors 8 are fed to a differential amplifier 9, to the output, which produces a voltage proportional to the angular displacement of the reflecting element 5.

The control unit 12 sequentially generates commands that control the interrupters 5 and 7 of the luminous flux and the arithmetic unit 10. When the first command comes from block 12, the interrupters and 7 overlap the SiBi flows and signal from the 9 U amplifier caused by the drift of the photodetectors 8 and the amplifier 9 enters the arithmetic unit 10, where it is stored. Upon receipt of the second command from block 12, the breaker 7 opens and the arithmetic unit 10 subtracts the previous one from the received signal L / z

and, t / 3 - t / i {/ dr-l. w. „mornings, r and

internal)

i / s is the signal at the output of block 10; In - signal generated by external light interference.

When the third command is received, the breaker 6 opens and closes

the chopper 7. The arithmetic unit W calculates the sum

-, s + G, - lr + ext 4- t / ext,

where 6 „„ even 11 is a signal generated by external light interference. When the fourth command is received, the breaker 7 opens. The arithmetic unit 10 calculates the difference

f / B, (/ s, 6dr -f 6p ,, e, uH H- t Biiyxp -f

+ and „- (t / lr -4- f / B ,, e ,, | i + vutr) i ...

where and is the signal characterizing the measured parameter.

The calculated signal is fed to the indicator //. This completes the measurement process.

Thus, as a result of switching by the interrupters of the luminous flux, the drift of the photodetectors, the amplifier, and also the internal and external light interference is compensated.

Claims (2)

1. Authors certificate of USSR Yar 501376, cl. G 02 B 27/30, 1973. 2. USSR author's certificate number 473977, cl. G 02 27/30, 1973 (prototype).