KR101196206B1 - Dither stabilizer and method thereof and fiber optic gyroscope using the same - Google Patents

Abstract

The present invention relates to a dither stabilization device and method for stabilizing the amplitude of dither in a high temperature or vibration environment, and an optical fiber gyroscope using the same. To this end, the dither stabilization apparatus according to the present invention includes: a dither amplitude detector for detecting a rotation output signal of an optical fiber gyroscope and calculating a dither amplitude based on the sensed rotation output signal; A dither generator for generating a reference dither signal; And a control unit for calculating a dither amplitude error between the reference dither amplitude included in the reference dither signal generated from the dither generator and the dither amplitude calculated by the dither amplitude detector.

Description

Dither stabilization apparatus and method, and optical fiber gyroscope using the same {DITHER STABILIZER AND METHOD THEREOF AND FIBER OPTIC GYROSCOPE USING THE SAME}

TECHNICAL FIELD The present invention relates to a dither stabilization apparatus and a method thereof, and more particularly, to a dither stabilization apparatus and a method of an optical fiber gyroscope.

Optical fiber gyroscopes that operate based on the principles of a sagnac interferometer include open-loop and closed-loop methods.

As shown in FIG. 1, the optical fiber gyroscope generates a dead zone 110 that is a low-speed rotation section that the gyroscope does not detect even when external rotation is applied. The conventional technique for solving this problem is a digital pulse dithering technique. This is a method of moving the operating point of the sensor to a high speed rotation section by applying a virtual large rotation in the form of a pulse in the signal processing process of a closed loop optical fiber gyroscope. In addition, the insensitive region is reduced in proportion to the magnitude of the dither amplitude, as shown in FIG. Therefore, the optical fiber gyroscope uses a dither amplitude set to a fixed value, which is optimally obtained through repeated tests, to remove the insensitive region. However, when the light intensity of the optical circuit changes due to high temperature or vibration, the improvement effect on the non-sensitive region is canceled by the change of the initially set dither amplitude. That is, as shown in Figure 3, in the normal state before the temperature rises, the gyroscope is arranged in the true north direction, and outputs the earth rotation angular velocity (about 12 deg / hr) corresponding to this. However, as the temperature rises and the temperature rises above 40 degrees, the output of the gyroscope gradually decreases. This phenomenon means that the gyroscope is reaching the insensitive region 122 that cannot measure the earth rotational angular velocity, which is a low angular velocity. At this time, the optical voltage representing the light intensity of the optical circuit is reduced in a similar form. That is, as the temperature rises, the photovoltage decreases, and thus an insensitive region appears.

An object of the present invention is to provide a dither stabilization apparatus and method for stabilizing the amplitude of dither in a high temperature or vibration environment.

Another object of the present invention is to provide a dither stabilization apparatus and a method for correcting loop gain by detecting an amplitude of dither which changes accordingly when light intensity changes.

Dither stabilization apparatus according to the present invention for achieving the above object, Dither amplitude detection unit for detecting a rotation output signal of the optical fiber gyroscope, and calculates the dither amplitude based on the sensed rotation output signal; A dither generator for generating a reference dither signal; And a control unit configured to calculate a dither amplitude error between the reference dither amplitude included in the reference dither signal generated by the dither generator and the dither amplitude calculated by the dither amplitude detector.

As an example related to the present invention, the dither amplitude detection unit accumulates the rotation output signal in the closed loop of the optical fiber gyroscope every half cycle of the dither signal, and the second successive value is followed by the accumulated value for the first half cycle. The difference value between the cumulative values during the half period may be calculated, and a value obtained by dividing the calculated difference value by 2 may be calculated as the dither amplitude.

As an example related to the present invention, the controller may calculate an output value based on the calculated dither amplitude error and a preset proportional gain.

As an example related to the present invention, the controller may reset and output the rotation control loop gain of the optical fiber gyroscope based on the calculated output value.

Dither stabilization method according to the present invention for achieving the above object comprises the steps of: sensing the rotational output signal of the optical fiber gyroscope; Calculating a dither amplitude based on the sensed rotational output signal; Calculating a dither amplitude error between a reference dither amplitude included in a reference dither signal generated from a dither generator and the calculated dither amplitude; And calculating an output value based on the calculated dither amplitude error and a preset proportional gain.

As an example related to the present invention, the calculating of the dither amplitude may include: accumulating the rotational output signal at every half period of the dither signal; Calculating a difference value between a first value accumulated during any first half period and a second value accumulated during a subsequent second half period; And calculating the dither amplitude by dividing the calculated difference by 2, which is a predetermined value.

As an example related to the present invention, the method may further include resetting and outputting a rotation control loop gain of the optical fiber gyroscope based on the calculated output value.

An optical fiber gyroscope using a dither stabilization apparatus according to the present invention for achieving the above object, the optical detector for converting light output from an integrated optical device into a current, a first amplifier for converting the converted current into a voltage, An A / D converter for converting the converted voltage into a digital signal, a demodulator for demodulating the digital signal, a rotation control loop gain for calculating an output value based on a signal output from the demodulator and a preset rotation control loop gain An optical fiber gyroscope using a dither stabilizing device comprising a management unit, an integrating unit generating and outputting a rotating output signal based on the output value, and a dither stabilizing device detecting the rotating output signal, wherein the dither stabilizing device comprises: Sensing the rotational output signal of the optical fiber gyroscope output from the integrating unit, and The rotational output dither amplitude detection unit for calculating on the basis of the dither signal amplitude of the optical fiber gyroscope; A dither generator for generating a reference dither signal; And a control unit configured to calculate a dither amplitude error between the reference dither amplitude included in the reference dither signal generated by the dither generator and the dither amplitude calculated by the dither amplitude detector.

As an example related to the present invention, the dither amplitude detector accumulates the rotation output signal every half cycle of a dither signal, and calculates a difference value between a value accumulated during a first half cycle and a value accumulated during a second half cycle. In addition, a value obtained by dividing the calculated difference value by 2 may be calculated as the dither amplitude.

As an example related to the present invention, the controller may calculate an output value based on the calculated dither amplitude error and a preset proportional gain.

As an example related to the present invention, the rotation control loop gain management unit may reset and output the rotation control loop gain of the optical fiber gyroscope based on the output value calculated from the control unit.

As an example related to the present invention, the controller may reset and output the rotation control loop gain of the optical fiber gyroscope based on the calculated output value.

Dither stabilization apparatus and method and an optical fiber gyroscope using the same according to an embodiment of the present invention, by removing the insensitive region by stabilizing the amplitude of the dither in a high temperature or vibration environment.

In addition, the dither stabilization apparatus and method and an optical fiber gyroscope using the same according to an embodiment of the present invention, by detecting the amplitude of the dither changes according to the change in the light intensity, to correct the loop gain, thereby adjusting the amplitude of the dither You can keep it constant.

1 is a diagram illustrating an insensitive region of an optical fiber gyroscope.
2 is a diagram showing the relationship between the dither amplitude and the insensitive region of the optical fiber gyroscope.
3 is a diagram showing a relationship between an output and an optical voltage of an optical fiber gyroscope according to temperature.
4 is a block diagram showing the configuration of a dither stabilization apparatus according to an embodiment of the present invention.
5 is a flowchart illustrating a dither stabilization method according to an embodiment of the present invention.
6A to 6C are diagrams illustrating a rotation output signal of a gyroscope including a dither signal and an input angular velocity according to an embodiment of the present invention.
7 is a block diagram showing the configuration of an optical fiber gyroscope having a dither stabilization device according to an embodiment of the present invention.
8 is a diagram showing the performance of an optical fiber gyroscope having a dither stabilization device according to an embodiment of the present invention.
9 is a flowchart illustrating a control method of an optical fiber gyroscope having a dither stabilization device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be denoted by the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted.

4 is a block diagram showing the configuration of a dither stabilization apparatus according to an embodiment of the present invention. As shown in the drawing, the dither stabilization apparatus 200 includes a dither amplitude detector 210, a dither generator 220, and It is composed of a control unit 230. Not all components of the dither stabilization apparatus 200 shown in FIG. 4 are essential components, and the dither stabilization apparatus 200 may be implemented by more components than those shown in FIG. The dither stabilization apparatus 200 may be implemented even with fewer components.

The dither amplitude detector 210 detects (or receives) a rotation output signal (or gyroscope rotation output information) of the gyroscope equipped with the dither stabilization device 200.

In addition, the dither amplitude detector 210 calculates a dither amplitude (or amplification of a dither signal) based on the detected rotation output signal of the gyroscope. At this time, the rotation output signal of the gyroscope (or the rotation output signal in the closed loop of the gyroscope) is a signal including dither signal and actual input angular velocity information.

The dither generator 220 generates (or sets) a reference dither signal. In this case, the reference dither signal is generated using a period (eg, T) of a preset dither signal and a preset dither amplitude (eg, K).

The controller 230 calculates a dither amplitude error (or an amplitude error of a dither signal) between the reference dither amplitude generated by the dither generator 220 and the dither amplitude calculated by the dither amplitude detector 210. At this time, the calculation of the dither amplitude error between the reference dither amplitude generated from the dither generator 220 and the dither amplitude calculated by the dither amplitude detector 210 is performed by an adder / subtractor (not shown), The dither amplitude error calculated by the adder / subtracter may be input to the controller 230.

In addition, the controller 230 calculates an output value based on the calculated dither amplitude error and a preset proportional gain.

The controller 230 sets a rotation control loop gain value of a gyroscope (or an optical fiber gyroscope) equipped with the dither stabilization device 200 based on the calculated output value, and sets the gyroscope. It is also possible to output the rotation control loop gain value of.

In addition, the dither stabilization apparatus 200 may be implemented as an electronic circuit, or may be implemented as a field programmable gate array (FPGA) device using a high speed integrated circuit hardware description language (VHDL) code.

In this manner, the dither stabilizing device can remove the insensitive region by stabilizing the amplitude of the dither in a high temperature or vibration environment.

As described above, when the light intensity changes, the dither stabilizing device can detect the amplitude of the dither changing accordingly, correct the loop gain, and keep the amplitude of the dither constant.

Hereinafter, the dither stabilization method according to the present invention will be described in detail with reference to FIGS. 4 to 6.

5 is a flowchart illustrating a dither stabilization method according to an embodiment of the present invention.

First, the dither amplitude detector 210 detects (or receives) a gyroscope rotation output signal (or gyroscope rotation output information), and dither amplitude (based on the detected gyroscope rotation output signal). Or amplitude of the dither signal). In this case, the rotation output signal of the gyroscope is a signal including a dither signal and an input angular velocity.

For example, as illustrated in FIGS. 6A to 6C, the dither amplitude detector 210 may rotate the output signal y (t) = y ₁ of the gyroscope including a dither signal and an actual input angular velocity. t) + y ₂ (t)) Here, in the dither signal y ₁ (t), the period of the dither signal is T, the dither amplitude is K, and the input angular velocity y ₂ (t) is A (= constant value). In this case, the input angular velocity detected by the gyroscope may be detected by excluding a dither signal. That is, as shown in the following equation, by accumulating the rotational output signal of the gyroscope every half cycle and adding up the two accumulated values acquired during one cycle, the input angular velocity A applied to the gyroscope can be obtained.

That is, the input angular velocity A applied to the gyroscope is

It can be obtained as

In addition, the dither amplitude can be obtained by subtracting the cumulative value for the next half period from the cumulative value for the half period, as shown in the following equation.

That is, the dither amplitude K is

와 같이 구할 수 있다(S110).

It can be obtained as (S110).

delete

Thereafter, the controller 230 calculates a dither amplitude error between the reference dither amplitude initially set by the dither generator 220 and the dither amplitude calculated by the dither amplitude detector 210.

For example, the controller 230 calculates an amplitude error K _ref -K of a dither signal expressed as a difference between the reference dither amplitude K _ref and the calculated dither amplitude K (S120).

Thereafter, the controller 230 calculates an output value based on the calculated dither amplitude error and a predetermined proportional gain.

For example, the controller 230 calculates the output value D _out by multiplying the predetermined proportional gain P by the dither amplitude error accumulated for one period, as shown in the following equation.

That is, the output value D _out of the controller 430 is

와 같이 구할 수 있다.

It can be obtained as

delete

The output value of the controller 230 is input to a rotation control loop gain management unit of a gyroscope (or an optical fiber gyroscope) equipped with a dither stabilization device 200, and the rotation control loop gain management unit is configured to control the control unit. The rotation control loop gain value of the gyroscope is set based on the output value of 230.

That is, the rotation control loop gain management unit resets (or adjusts) the rotation control loop gain value of the gyroscope based on the output value of the controller 230 as shown in the following equation.

That is, the gyroscope rotation control loop gain value is

Can be represented as

here,

G: Gyroscope Rotation Control Loop Gain

G ': Reset (adjusted) gain of the gyroscope rotation control loop

(S130).

As described above, the dither stabilization apparatus 200 calculates a dither amplitude error based on the gyroscope's rotation output signal, and reduces the calculated dither amplitude error (for example, a dither amplitude error has a value of "0"). Output) by adjusting the output value.

7 is a block diagram showing the configuration of an optical fiber gyroscope 700 having a dither stabilization device according to an embodiment of the present invention.

As shown in FIG. 7, the optical fiber gyroscope 700 includes a light source 701, an integrated optical element 702, an optical fiber ring 703, an optical detector 704, a first amplifier 705, A / D converter 706, demodulator 707, rotation control loop gain manager 708, integrator 709, vertical dyne generator 710, square wave generator 711, A D / A converter 712, a second amplifier 713, and a dither stabilizer 200 are included. Here, the optical fiber gyroscope 700 may be a closed-loop optical fiber gyroscope.

The light source 701 generates and outputs light.

The integrated optical device 702 divides the light output from the light source 701 in two directions through an optical coupler (not shown) included in the integrated optical device 702. ) That is, the optical coupler divides the light output from the light source 701 into two lights in different directions and outputs the light to the optical fiber ring 703. In this case, the integrated optical device 702 inputs one of the two lights to the optical fiber ring 703 in a clockwise direction, and inputs the other of the two lights to the optical fiber ring 703. In the counterclockwise direction.

In addition, the integrated optical device 702, the light detection unit through the optical coupler two lights (light rotated clockwise and light rotated counterclockwise) respectively output from the optical fiber ring 703 To 704.

In addition, the integrated optical device 702 may output a phase difference generated by external rotation with respect to light output to the optical fiber ring 703 based on a signal including rotation information output from the second amplifier 713. Compensating and outputting the phase compensated light to the optical fiber ring 703.

The optical fiber ring 703 receives two lights output from the integrated optical device 702, and rotates (or moves) the two lights in clockwise and counterclockwise directions, respectively.

The light detector 704 converts light output from the integrated optical device 702 into a current.

The first amplifier 705 converts the current converted from the light detector 704 into a voltage.

The A / D converter 706 converts the voltage converted from the first amplifier 705 into a digital signal and outputs the digital signal.

The demodulator 707 demodulates and outputs the digital signal output from the A / D converter 706.

The rotation control loop gain management unit 708 calculates an output value based on the signal output from the demodulation unit 707 and a preset rotation control loop gain.

The rotation control loop gain management unit 708 resets (or updates) the rotation control loop gain value of the optical fiber gyroscope 700 based on the output value calculated from the dither stabilization apparatus 200.

The integrator 709 integrates and outputs the output value of the rotation control loop gain management unit 708. That is, the integrator 709 outputs a rotation output signal (or rotation output information) of the optical fiber gyroscope 700 based on the output value of the rotation control loop gain management unit 708.

The vertical dyne generator 710 may use the rotary output signal of the optical fiber gyroscope 700 output from the integrator 709 to generate a sawtooth wave signal accumulated at a predetermined time of the optical fiber ring 703. Create The slope of the sawtooth signal is proportional to the magnitude of the input rotation value. In addition, a predetermined time of the optical fiber ring 703 is a reciprocal of a proper frequency according to the optical fiber length, and represents a time delay occurring in the optical fiber ring 703. As an example, when the optical fiber is wound in a ring of about 200 m, the proper frequency is 500 kHz and the time delay is about 2 u seconds. That is, the longitudinal dyne generator 710 generates a feedback signal by continuously accumulating the phase difference due to the rotation by using a digital counter at every appropriate frequency period of the optical fiber ring 703.

In addition, the longitudinal dyne generator 710 integrates the rotation output signal of the optical fiber gyroscope 700 output from the integrator 709 into a sawtooth wave-shaped signal (generates). Subsequently, after the sawtooth wave signal generated by the longitudinal dyne generator 710 and the signal generated by the square wave generator 711 are combined, the combined signal is input to the D / A converter 712. do.

The D / A converter 712 converts the sawtooth wave digital signal into an analog signal (eg, voltage) and outputs the analog signal.

The second amplifier 713 amplifies the voltage output from the D / A converter 712 and outputs the amplified voltage to the integrated optical device 702.

The dither stabilization apparatus 400 detects a rotation output signal of the optical fiber gyroscope 700 output from the integrator 709 and based on the detected rotation output signal of the optical fiber gyroscope 700. Calculate the dither amplitude.

In addition, the dither stabilization apparatus 400 calculates a dither amplitude error between a predetermined reference dither amplitude and the calculated dither amplitude, calculates an output value based on the calculated dither amplitude error and a predetermined proportional gain, and The calculated output value is output to the rotation control loop gain management unit 708.

8 is a diagram illustrating a relationship between a conventional method of inputting a fixed dither value and an output according to a rotational input of an optical fiber gyroscope to which the dither stabilization apparatus 200 according to the present invention is applied. As shown in FIG. 8, in the optical fiber gyroscope to which the dither stabilization apparatus 200 according to the present invention is applied, it can be seen that the insensitive region is completely removed at a high temperature.

9 is a flowchart illustrating a control method of an optical fiber gyroscope having a dither stabilization device according to an embodiment of the present invention.

First, the integrated optical device 702 divides the light output from the light source 701 into two directions through an optical coupler (not shown) included in the integrated optical device 702 and outputs it to the optical fiber ring 703. .

For example, the integrated optical device 702 inputs one of the two lights clockwise into the optical fiber ring 703 and inputs the other of the two lights into the optical fiber ring. Input to the counterclockwise direction (703) (S210).

Thereafter, the integrated optical device 702 may include two lights (light rotated clockwise and light rotated counterclockwise) respectively output from the optical fiber ring 703 through the optical coupler. The light detector 704 converts the light output from the integrated optical device 702 into a current (S220).

Thereafter, the converted current is converted into a voltage through the first amplifier 705, the A / D converter 706, and the demodulator 707, and the converted voltage is converted into a digital signal. The signal converted into the digital signal is demodulated and output to the rotation control loop gain management unit 708 (S230).

Thereafter, the rotation control loop gain manager 708 calculates an output value based on the signal output through the demodulator 707 and a preset rotation control loop gain (S240).

Thereafter, the integrator 709 integrates and outputs the output value of the rotation control loop gain management unit 708. That is, the integrator 709 outputs a rotation output signal (or rotation output information) of the optical fiber gyroscope 700 based on the output value of the rotation control loop gain management unit 708 (S250).

Thereafter, the dither stabilization apparatus 400 detects the rotation output signal of the optical fiber gyroscope 700 output from the integrating unit 709, and outputs the rotation output signal of the sensed optical fiber gyroscope 700. Calculate dither amplitude as a basis.

In addition, the dither stabilization apparatus 400 calculates a dither amplitude error between a predetermined reference dither amplitude and the calculated dither amplitude, and calculates an output value based on the calculated dither amplitude error and a predetermined proportional gain (S260). ).

Thereafter, the rotation control loop gain manager 708 resets (or updates) the rotation control loop gain value of the optical fiber gyroscope 700 based on the output value calculated from the dither stabilization device 400, An output value is calculated based on the reset control loop gain value of the reset optical fiber gyroscope 700 and the signal output through the demodulator 707 and output to the integrator 709.

In addition, the integrating unit 709 outputs the calculated output value (or rotation output signal) to the vertical dyne generating unit 710 (S270).

Thereafter, the calculated output value is obtained through the integrated optical device 702 through the vertical dyne generator 710, the square wave generator 711, the D / A converter 712, and the second amplifier 713. In step S280).

Thereafter, the integrated optical device 702 may adjust a phase difference generated by external rotation with respect to light output to the optical fiber ring 703 based on a signal including rotation information output from the second amplifier 713. Compensating, and outputs the light compensated for the phase difference to the optical fiber ring (703) (S290).

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

200: dither stabilization device 210: dither amplitude detection unit
220: dither generator 230: controller
700: optical fiber gyroscope 701: light source
702: integrated optical element 703: optical fiber ring
704: light detector 705: first amplifier
706: A / D converter 707: demodulator
708: rotation control loop gain management unit 709: integrator
710: vertical dyne generator 711: square wave generator
712: D / A converter 713: second amplifier

Claims (12)

delete A dither amplitude detector for detecting a rotation output signal of an optical fiber gyroscope and calculating a dither amplitude based on the sensed rotation output signal;
A dither generator for generating a reference dither signal; And
And a controller configured to calculate a dither amplitude error between the reference dither amplitude included in the reference dither signal generated from the dither generator and the dither amplitude calculated by the dither amplitude detector.
The dither amplitude detector accumulates a rotation output signal in the closed loop of the optical fiber gyroscope every half period of the dither signal, and a difference value between a value accumulated during a first half period and a value accumulated during a subsequent second half period. And calculating the dither amplitude by dividing the calculated difference value by two. 3. The apparatus of claim 2,
Dither stabilization apparatus characterized in that the output value is calculated based on the calculated dither amplitude error and a predetermined proportional gain. The apparatus of claim 3,
Dither stabilization apparatus according to the calculated output value, characterized in that for outputting by resetting the rotation control loop gain of the optical fiber gyroscope. Sensing a rotational output signal of the optical fiber gyroscope;
Calculating a dither amplitude based on the sensed rotational output signal;
Calculating a dither amplitude error between a reference dither amplitude included in a reference dither signal generated from a dither generator and the calculated dither amplitude; And
And calculating an output value based on the calculated dither amplitude error and a preset proportional gain. The method of claim 5, wherein calculating the dither amplitude comprises:
Accumulating the rotation output signal at every half period of the dither signal;
Calculating a difference value between a first value accumulated during any first half period and a second value accumulated during a subsequent second half period; And
Dither stabilization method comprising the step of calculating a value obtained by dividing the calculated difference value by a predetermined value of 2 as the dither amplitude. The method of claim 5,
And resetting the rotation control loop gain of the optical fiber gyroscope based on the calculated output value to output the dither stabilization method. A light detector for converting light output from an integrated optical device into a current, a first amplifier for converting the converted current into a voltage, an A / D converter for converting the converted voltage into a digital signal, and demodulating the digital signal A demodulation unit, a rotation control loop gain management unit calculating an output value based on a signal output from the demodulation unit and a preset rotation control loop gain, an integrating unit generating and outputting a rotation output signal based on the output value, and the rotation In the optical fiber gyroscope using a dither stabilization device comprising a dither stabilization device for detecting an output signal,
The dither stabilization device,
A dither amplitude detector for detecting a rotation output signal of the optical fiber gyroscope output from the integrator and calculating a dither amplitude based on the detected rotation output signal of the optical fiber gyroscope;
A dither generator for generating a reference dither signal; And
And a control unit configured to calculate a dither amplitude error between the reference dither amplitude included in the reference dither signal generated from the dither generator and the dither amplitude calculated by the dither amplitude detection unit. scope. The method of claim 8, wherein the dither amplitude detection unit,
Accumulating the rotation output signal every half period of the dither signal, calculating a difference value between a value accumulated during a first half period and a value accumulated during a second half period, and dividing the calculated difference value by two. An optical fiber gyroscope using a dither stabilization device, characterized in that it is calculated by dither amplitude. The method of claim 8, wherein the control unit,
An optical fiber gyroscope using a dither stabilizing device, characterized in that for calculating an output value based on the calculated dither amplitude error and a predetermined proportional gain. The method of claim 10, wherein the rotation control loop gain management unit,
An optical fiber gyroscope using a dither stabilizing device, characterized in that for outputting by resetting the rotation control loop gain of the optical fiber gyroscope based on the output value calculated from the controller. delete

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