RU2461798C1 - Device for angle measurement - Google Patents

Abstract

FIELD: weapons and ammunition.

SUBSTANCE: device comprises a linear polarisation channel in the form of a radiator of monochromatic radiation, a polariser prism, an analyser prism and a recorder. The device additionally includes an electromechanical tracking system made in the form of an induction angle detector, a test motor and an electronic control unit. The analyser prism is rigidly fixed on the rotor of the induction angle detector at the angle to the zero position of the induction angle detector.

EFFECT: expanded operational possibilities, increased range and accuracy of angle values measurements.

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Description

The invention relates to photoelectric measuring devices for measuring angles, angular coordinates and angular displacements based on the use of polarizing optics.

Known devices that provide measurements of angular quantities based on the use of geometric and polarization optics, where the accuracy of the measurements depends on the accuracy of the manufacture of masks deposited on the optical elements, on the location of the optical elements (diffraction errors), or the non-linearity of the transmitted light intensity characteristics affects the accuracy, which limits the range of measurement of angles, with a given accuracy [1, 2].

The closest technical solution to the proposed invention is a device for measuring torsion angles [3]. The device consists of a linear polarization channel in the form of a naturally polarized emitter and a prism-polarizer optically coupled to it, an analyzer prism that can be rotated about the optical axis, with a mechanical probe inserted into the rotation bearing race, and a polarization plane recorder.

The disadvantages of the above device are the lack of a static zero reference to the registrar and the inability to make measurements in dynamics.

The main task to which the invention is directed is to expand the operational capabilities of the device for measuring angle, increasing the range and accuracy of measuring angular values.

To solve this problem, a device for measuring the angle is proposed, which, like the prototype, contains a linear polarization channel in the form of a monochromatic radiation emitter, a polarization prism, an analyzer prism, and a recorder.

Unlike the prototype, an electromechanical servo system is additionally introduced into the device, made in the form of an induction angle sensor, a mining engine and an electronic control unit, while the prism analyzer is rigidly fixed to the rotor of the induction angle sensor at an angle to the zero position of the induction angle sensor.

The essence of the invention lies in the fact that the device for measuring the angle has a fixed zero position associated with the zero position of the induction angle sensor, and the range of measured angles from 0 to 360 °, while in the entire range of measured angles from 0 to 360 °, the polarization channel works in a linear zone.

To improve the accuracy of measurements, the device has two reference systems: rough, in the form of a signal from an induction angle sensor and accurate, in the form of a signal from a polarization channel recorder.

The amplitude-phase detection of the signal of the registrar of the polarization channel is carried out due to the artificial knocking down of the device’s “zero”, in the form of an additional turn of the analyzer prism by a small angle relative to the rotor of the induction angle sensor and compensation of this turn by an additional electric signal, introduced in antiphase to the addition to the main signal of the recorder.

The essence of the invention lies in the fact that for any mutual rotations of objects A and B (see Figs. 1 and 2), it is possible to measure the absolute mutual angle of rotation between them in the zone of linear dependence, i.e. without loss of measurement accuracy.

The invention is illustrated by drawings, where figure 1 and figure 2 presents the optical-kinematic diagram of the device; figure 3 is an electrical functional diagram of a device; figure 4 - drawings of masks deposited on the optical elements to determine the position of the device relative to the "false zero"; figure 5 - graphs of the signals of the registrar measuring angle at various modes of operation of the device.

The angle measuring device consists of a monochromatic radiation emitter 1, a laser type, a red light spectrum, with natural polarization, a test emitter 2, a violet light spectrum (ordinary LED), a plane-parallel plate with a mask 3, a beam splitter plate 4, a brightness feedback photodetector 5, prism-polarizer 6, prism-analyzer 7, induction angle sensor 8, bearing 9, mining engine 10 and recorder 11.

The angle measuring device contains electronic units and devices for signal processing and control, depicted in the electrical functional diagram shown in figure 3: the switching unit 12 to turn on the emitter-test 2, the automatic gain control device (AGC) 13 to maintain radiation stability in brightness monochromatic radiation emitter 1, preamplifier filter 14 for filtering the feedback photodetector signal according to brightness 5, temperature sensor 15 mounted on the recorder housing 11 for computer sensing the temperature drift of zero and the gain of the registrar 11; a control unit 16, comprising a pre-filter for filtering and amplifying the signal of the recorder 11, a 12-bit analog-to-digital converter (ADC) for digitizing the signal of the recorder 11; analog phase detector (AFD); single-chip computer for processing: signals from the recorder 11, the induction angle sensor 8 and the temperature sensor 15; control: mining engine 10, switching unit 12 and indicating unit 17, which gives information about the measured angle in visual form; a secondary analog-to-digital angle converter for converting a signal from an induction angle sensor 8; a universal torque motor controller for controlling the mining engine 10. The electronic control unit 16 also includes an external interface for connecting to a computer network for external maintenance and data transmission. The electronic control unit 16 provides visual information to the display unit 17.

The operation of the device is as follows.

After applying power to the device and turning on the laser diode, the light beam from the monochromatic radiation emitter 1 passes through the beam splitter plate 4, enters the upper face of the polarizing prism 6 and enters the surface of the feedback photodetector in brightness 5. Prism-polarizer 6, monochromatic radiation emitter 1 and a test emitter 2, a brightness feedback photodetector 5, a plane-parallel plate with a mask 3 and a beam splitter plate 4 are rigidly connected to the body of the object A. Passing through the prisms -polarizer 6, a plane-polarized light beam enters the prism analyzer 7 and then to the recorder 11. From the brightness feedback 5 photodetector having a narrowband sensitivity in the red light spectrum, a signal proportional to the brightness of the monochromatic radiation emitter 1 goes to the preamplifier filter 14 and, further, to the AGC device 13, which regulates the current of the emitter of monochromatic radiation 1, stabilizing the brightness of its radiation. The preamplifier filter 14 not only amplifies the feedback signal, but also filters it from high-frequency components associated with the noise of the feedback photodetector for brightness 5. The rotor of the mining engine 10 is rigidly connected with the rotor of the inductive angle sensor 8 of the inner race of the bearing 9 and the prism analyzer 7 The outer bearing race 9, the stator of the mining engine 10, the stator of the inductive angle sensor 8 and the recorder 11 are rigidly connected to the body of the object B. In operating mode, a signal depending on the brightness of the plane polarization from the recorder 11 of this light and the angle of mutual reversal of the prism-polarizer 6 and the prism-analyzer 7 (according to the law of Malus [4]), enters the electronic control unit 16, which gives a control signal to the mining engine 10. The mining engine 10 starts to unfold, while the rotor turns mining engine 10, the rotor of the inductive angle sensor 8 and the prism analyzer 7 relative to the body of object B is made to the “zero” cross position of the prism polarizer 6 and the prism analyzer 7, i.e. to the minimum signal value from the recorder 11. At the same time, a signal proportional to the angle of rotation of its rotor relative to the stator is taken from the induction angle sensor 8, i.e. the turning angle of the object A relative to the object B (rough reading of the device). This signal enters the control unit 16, where it is digitized and added to the digitized residual signal of the recorder 11 (exact readout of the device), which is formed as the sum of the static and dynamic errors of the electromechanical servo system: "Registrar 11 - control unit 16 - mining engine 10"; then the signal is issued to the display unit 17 to the consumer in the form of a digital angle value. Further, the electromechanical tracking system "Registrar 11 - electronic control unit 16 - mining engine 10" constantly monitors the position of the prism-polarizer 6 and the prism-analyzer 7 within an accurate reference, avoiding their large mismatch, with the output of the instantaneous angle between objects A and B .

At the beginning of the operation of the device, in order to exclude the capture of “false zero” by it, a setting is made - an exhibition of the device's zero position. For this, the optical channel of the test emitter 2 is used. On the lower surface (base) of the prism analyzer 7, a special coating is applied, the layer of which is transparent to red light and opaque to violet. The same coating is applied to a plane-parallel plate with a mask 3. The coating is applied so that it covers a little more than half the light diameter of the beam falling on these elements, as shown in figure 4, where: a) is a conditional view of the mask on a plane-parallel plate with mask 3 from the side of the emitter test 2; b) - conditional view of the mask based on the prism-analyzer 7 from the side of the emitter-test 2; c) - conditional view on the surface of the recorder 11 from the side of the emitter-test 2 during mutual rotation of the prism-polarizer 6 and the prism-analyzer 7 by 180 °; g) - conditional view on the recorder 11 from the side of the test emitter 2 with a mutual turn of the prism-polarizer 6 and the prism-analyzer 7 by 0 °.

The location of the masks on a plane-parallel plate with a mask 3 and a prism analyzer 7 with respect to the optical channel connecting the object A and object B is such that only when the device is in true zero, the light from the test emitter 2 does not enter the recorder 11. When power is supplied from the electronic control unit 16, a signal is output to the switching unit 12 and the emitter-test 2 is turned on. The light beam of the emitter-test 2 passes through a plane-parallel plate with a mask 3 to the beam splitter plate 4 and, being reflected from it, is sent to the main polarizing channel through the prism-polarizer 6 and the prism-analyzer 7 to the registrar 11. In this case, the light from the emitter of monochromatic radiation 1 also enters the registrar 11. At the same time, a signal to the motor is output from the control unit 16 spruce mining 10 proportional to the rated motor speed. The phase of the signal is selected so that the rotation of the prism-analyzer 7 from the side of the prism-polarizer 6 is observed clockwise. This phase is considered negative.

In whatever position the device was at the beginning of operation, without passing the “false zero” the device does not start working in normal mode. The mining engine 10 deploys the prism analyzer 7 until the control unit 16 receives a signal from the recorder 11 about the passage of "false zero". The graphs of the signals received by the electronic control unit 16 from the recorder 11 are shown in FIG. 5, which shows the conditional graphs of the signals from the recorder 11 and the control unit 16:

U _FP - voltage signal from the recorder 11;

φ _P-A is the angle between the prism-polarizer 6 and the prism-analyzer 7;

Ů is the derivative of the voltage of the signal of the recorder 11;

φ _K is the angle of rotation of the prism-polarizer 6 and the prism-analyzer 7 for the red spectrum beam;

φ _Ф - angle of rotation of the prism-polarizer 6 and prism-analyzer 7 for the violet spectrum beam;

- напряжение сигнала компенсации.

- voltage compensation signal.

The value of the signal from the registrar 11 in the "false zero" exceeds the value of the signal in true zero.

After passing “false zero” from the control unit 16 to the switching unit 12, a signal is issued to turn off the test emitter 2, and the mining engine 10 continues to turn the prism analyzer 7 in the same direction until the device switches to operating mode, while the recorder 11 receives the luminous flux is only from the emitter of monochromatic radiation 1, the phase of the control signal of the mining engine 10 remains the same.

To ensure the operation of the device in operating mode, the electronic control unit 16 provides a control signal to the mining engine 10 of the corresponding amplitude and phase. The value of the amplitude and phase of the output signal of the electronic control unit 16 is formed by the AFD as part of the electronic control unit 16.

, где φ_∂мах - максимальная динамическая ошибка электромеханической следящей системы: «регистратор 11 - электронный блок управления 16 - двигатель отработки 10»;The AFD operates as follows: initially, when the prism analyzer 7 is installed on the rotor of the induction angle sensor 8, the zero (crossed) position of the prism analyzer 7 relative to the polarization prism 6 is deployed relative to the zero position of the induction angle sensor 8 (rotor-stator), some initial angle φ ₀ , and in this position they are rigidly fastened (the rotor of the induction angle sensor 8 is the prism analyzer 7). The angle φ ₀ is selected from the condition

, where φ _∂max is the maximum dynamic error of the electromechanical servo system: "recorder 11 - electronic control unit 16 - mining engine 10";

φ _smah - the maximum static error of the same system;

φ _lfmah - the maximum angle of rotation between the prisms of the analyzer 7 and the polarizer 6, at which the signal from the recorder 11 is in the linear zone.

When the operating mode is switched on after passing “false zero” in the control unit 16 to the signal coming from the registrar 11 in the control circuit: “recorder 11 - pre-filter-ADC-AFD”, a signal is added in antiphase, the amplitude corresponding to the angle φ ₀ . This happens at the moment when the angle φ <φ ₀ remains to the zero coordinated position of the prism analyzer 7 and the prism polarizer 6 (by the amplitude of the signal from the recorder 11), while the signal φ ₀ is output in the negative phase, and the signal from the recorder 11 the phase is considered positive (see figure 5). After that, the electromechanical tracking system begins to fully monitor the amplitude and phase of the signal of the recorder 11 and the device enters the operating mode.

To compensate for the temperature effect on the operation of the device, a temperature sensor 15 is rigidly fixed to the recorder 11, the signal from which is sent to the control unit 16. The transmission coefficient and zero drift of the signal from recorder 11 are adjusted in software mode by the amplitude of this signal when temperature conditions change.

The main advantage of the claimed invention is the ability to obtain information about the relative position of two objects A and B relative to the measuring axis in real time without limiting the magnitude of the measured angle, which extends the operational capabilities of the device for use in various devices and systems.

Information sources

1. Russian Federation patent No. 2116618, IPC G01B 11/26, publ. 07/27/1998.

2. Japan patent No. JP5223552 (A), IPC: G01B 11/26, publ. 08/31/1993.

3. Russian Federation, patent No. 2073198, IPC G01B 11/26, publ. 02/10/1997 - a prototype.

4. A.A. Detlaf, B.M. Yavorsky. Physics course T.3 M .: Higher school, 1979, p. 151-154.

Claims (1)

A device for measuring the angle, containing a linear polarizing channel in the form of a monochromatic radiation emitter, a polarizing prism, an analyzer prism and a registrar, characterized in that the device is additionally equipped with an electromechanical tracking system made in the form of an induction angle sensor, a mining engine and an electronic control unit while the prism analyzer is rigidly fixed to the rotor of the induction angle sensor at an angle to the zero position of the induction angle sensor.

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