CN101216314A - Resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus and method - Google Patents

Abstract

The invention discloses a frequency feedback and tracking device for the digital closed loop system of a resonant-type optical gyroscope and a method thereof. A laser is sequentially connected with a Y-splitter, a first phase modulator, a first circulator, a coupler, a second circulator, a second photoelectric detector, a second digital signal processing circuit and the laser to form a closed loop counterclockwise optical path and a signal processing circuit; the laser is sequentially connected with the Y-splitter, a second phase modulator, a second circulator, the coupler, the first circulator, a first photoelectric detector, a first digital signal processing circuit, a second combined saw-tooth wave generator and the second phase modulator to form a closed loop clockwise optical path and a signal processing circuit; the first phase modulator is connected with a first combined saw-tooth wave generator; and the coupler is connected with a circular resonant cavity. The invention is helpful for solving transcendental equation solution difficulty when performing open loop test; is helpful for suppressing interference and improving response characteristics of the system; and can be easily implemented on a digital signal processing (DSP) chip.

Description

Resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus and method

Technical field

The present invention relates to a kind of resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus and method.Software algorithm involved in the present invention is simple and reliable, and can realize frequency lock fast, and the frequency feedback tracking lock method that the present invention proposes can realize on digital signal processing chip DSP more easily.

Background technology

Resonance type optical gyroscope is to utilize optics Sagnac effect to realize a kind of high-precision inertia sensing device that detects rotating.The core sensing unit of resonance type optical gyroscope is a passive annular resonant cavity of being made up of optical waveguide or optical fiber, be called for short resonator cavity, the axle that winds perpendicular to the plane, place when resonator cavity rotates, the resonance frequency that then between the light beam of the clockwise and counterclockwise direction of propagation generation is proportional to angular velocity of rotation in the resonator cavity is poor, just can obtain the carrier angular velocity of rotation by detecting this resonance frequency difference.New high-performance resonance type optical gyroscope generally tends to the digital closed loop detection scheme, by the frequency of FEEDBACK CONTROL input resonator, makes in the resonator cavity all to be in resonant condition with counterclockwise transmission light clockwise.Therefore, frequency feedback tracking lock technology is occupied important status in the resonance type optical gyroscope closed-loop system.

Summary of the invention

The object of the invention provides a kind of resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus and method.

Resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus is by the laser instrument that is connected successively, the Y splitter, first phase-modulator, first circulator, coupling mechanism, second circulator, second photodetector, second digital signal processing circuit, laser instrument constitutes counterclockwise light path of closed loop and signal processing circuit, by the laser instrument that is connected successively, the Y splitter, second phase-modulator, second circulator, coupling mechanism, first circulator, first photodetector, first digital signal processing circuit, the second combination saw-toothed wave generator, second phase-modulator constitutes clockwise light path of closed loop and signal processing circuit, first phase-modulator links to each other with the first combination saw-toothed wave generator, and coupling mechanism links to each other with ring resonator.

Described first digital signal processing circuit comprises first analog-digital converter, first digital lock-in amplifier, first digital filter, first digitial controller and first digital analog converter that is connected successively.

Second digital signal processing circuit comprises second analog-digital converter, second digital lock-in amplifier, second digital filter, second digitial controller and second digital analog converter that is connected successively.

The first combination saw-toothed wave generator comprises the first digital saw-toothed wave generator, the 3rd digital analog converter that is connected; The second combination saw-toothed wave generator comprises the second digital saw-toothed wave generator, the 4th digital analog converter that is connected.

The resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking means comprises the steps:

1) in counterclockwise light path of closed loop and signal processing circuit, be f with the first combination saw-toothed wave generator, 13 generated frequencies ₁And 2f ₁, repetition frequency is the combination sawtooth wave of p, the frequency that laser instrument 1 sends is that the laser of f is subjected to f ₁And 2f ₁Combination frequency modulation, through counterclockwise light path, second photodetector, 10 output frequencies are the square-wave signal of p, square wave amplitude I _DoutExpression formula be, $I_{\mathrm{Dout}}\left(\mathrm{\&Delta;f}\right)=(1-{\mathrm{\&alpha;}}_C)\mathrm{\&rho;}{\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">I</figure-callout>}}_0\&lsqb;\frac{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2}{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2+{(\mathrm{\&Delta;f}-\frac{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}{2})}^2}-\frac{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2}{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2+{(\mathrm{\&Delta;f}+\frac{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}{2})}^2}\&rsqb;,$ Resonance frequency deviation delta f is meant the difference of the resonance frequency of the laser frequency that enters ring resonator 8 and ring resonator itself, and $\mathrm{\&Delta;f}=f+\frac{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1+{2\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}{2}-f^{\mathrm{CCW}},$ f ^CCWBe the resonance frequency of counterclockwise light path, C ₀, α _C, the systematic parameter that ρ is and modulating frequency is irrelevant is near zero in the resonance frequency deviation, and square wave amplitude and resonance frequency deviation have monotone increasing, and slope is the linear approximate relationship area I of k, is monotone area II of subtraction function character in the area I both sides; In clockwise light path of closed loop and signal processing circuit, be f with the second combination saw-toothed wave generator, 14 generated frequencies ₂And f ₁+ f ₂, f ₂Adjustable, and initial value is made as f ₁, repetition frequency is the combination sawtooth wave of p, the square wave amplitude I of first photodetector, 9 outputs _DoutIdentical with the expression formula of resonance frequency deviation delta f with counterclockwise light path, but the resonance frequency deviation $\mathrm{\&Delta;f}=f+\frac{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_2+{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_2}{2}-f^{\mathrm{CW}},$ f ^CWIt is the resonance frequency of clockwise light path;

2) criterion 1:|I is introduced in judgement system original state zone of living in _Dout2|＞| I _Dout1|, I _Dout1And I _Dout2Be respectively when the resonance frequency deviation be Δ f ₁With Δ f ₂The time demodulation square wave amplitude that obtains, i.e. I _Dout1=I _Dout(Δ f ₁), I _Dout2=I _Dout(Δ f ₂).Δ f ₀Resonance frequency deviation during for system start-up, assignment Δ f ₁=Δ f ₀, feedback frequency difference δ f ₁=-I _Dout1/ k, Δ f ₂=Δ f ₁+ δ f ₁,, then represent frequency difference Δ f if criterion 1 is set up ₁Fall into area I I, feedback frequency difference δ f ₂=-sign (I _Dout1) | Δ f _m|, Δ f here _mBe the free spectrum width FSR of ring resonator 8 and the product of scale-up factor, δ f ₂Introducing be in order when the resonance frequency deviation is positioned at area I I, to enter the unlikely again both sides vibration at area I I of area I, Δ f simultaneously faster ₁=Δ f ₂+ δ f ₂, feed back frequency difference δ f again ₁=-I _Dout1/ k, Δ f ₂=Δ f ₁+ δ f ₁, carry out criterion 1, be false until criterion 1, then Δ f ₁Enter area I, wherein sign (x) is a sign function, when x is timing, be output as+1, when x when negative, be output as-1;

3) enter and carry out tuning-points after the area I and differentiate, introduce criterion 2:|I _Dout1|=0, if criterion 2 is false, then feed back frequency difference δ f ₁=-I _Dout1/ k, Δ f simultaneously ₁=Δ f ₁+ δ f ₁, to set up until criterion 2, EOP (end of program) is locked in tuning-points;

4) with parameter δ f _tCome the feedback frequency difference of the clockwise light path of accumulative total, to counterclockwise light path, the feedback frequency difference realizes that by the laser frequency f that regulates laser instrument 1 output to clockwise light path, the feedback frequency difference is by regulating the combination sawtooth wave frequency f of the second combination saw-toothed wave generator, 14 outputs ₂Realize that after light path locked tuning-points counterclockwise, when gyro did not rotate, light path also was in resonant condition, f clockwise ₂Initial value is made as f ₁When gyro has the angular velocity of rotation of Ω, light path will no longer be in resonant condition clockwise, need to introduce feedback branch controlled frequency f ₂Size, after each feedback, f ₂=f ₁+ δ f _t, lock onto tuning-points after, the δ f of the gained that adds up _tThe resonance frequency that promptly is clockwise light path and counterclockwise light path is poor, utilizes this resonance frequency difference just can obtain the teetotum tarnsition velocity.

The present invention introduces the modulation of bifrequency combination sawtooth wave, utilizes the relation of photodetector output square-wave signal amplitude and resonance frequency deviation, has proposed resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus and method.The software algorithm that the present invention proposes is simple and reliable, and can realize the locking of resonance frequency fast, thereby avoids the rooting algorithm of resonance frequency deviation complexity.The frequency feedback tracking lock method that the present invention proposes can realize on digital signal processing chip DSP more easily.

Description of drawings

Fig. 1 is the resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus structured flowchart;

Fig. 2 is the first digital signal processing circuit block diagram of the present invention;

Fig. 3 is the second digital signal processing circuit block diagram of the present invention;

Fig. 4 is the first combination saw-toothed wave generator circuit block diagram of the present invention;

Fig. 5 is the second combination saw-toothed wave generator circuit block diagram of the present invention;

Fig. 6 is that frequency is f ₁And 2f ₁Combination sawtooth wave-wave shape figure;

Fig. 7 is photodetector output square-wave signal figure;

Fig. 8 is the graph of a relation of detector output normalization square wave amplitude and resonance frequency deviation;

Fig. 9 is frequency locking scheme software realization flow figure;

Among the figure: laser instrument 1, Y splitter 2, the first phase place system device 3, second phase-modulator 4, first circulator 5, second circulator 6, coupling mechanism 7, ring resonator 8, first photodetector 9, second photodetector 10, first digital signal processing circuit 11, second digital signal processing circuit 12, the first combination saw-toothed wave generator 13, the second combination saw-toothed wave generator 14, first analog-digital converter 15, first digital lock-in amplifier 16, first digital filter 17, first digitial controller 18, first digital analog converter 19, second analog-digital converter 20, second digital lock-in amplifier 21, second digital filter 22, second digitial controller 23, second digital analog converter 24, the first digital saw-toothed wave generator 25, the 3rd digital analog converter 26, the second digital saw-toothed wave generator 27, the 4th digital analog converter 28.

Embodiment

The present invention utilizes in bifrequency combination modulating resonance formula optical gyroscope system, the gyro output signal is a square wave, near and square wave amplitude and the resonance frequency deviation linear approximate relationship close tuning-points, proposed simply needing to obtain the frequency shift amount of FEEDBACK CONTROL divided by the slope on the tuning-points with square wave amplitude, outside being in the approximately linear district during inelastic region of both sides, with a bigger suitable fixedly amounts of frequency offset control, make the resonance frequency deviation enter linear zone fast, utilize so repeatedly feedback frequency to operate to follow the tracks of successively the tuning-points of the clockwise and counterclockwise light beam of optical gyroscope.

As shown in Figure 1, resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus is by the laser instrument 1 that is connected successively, Y splitter 2, first phase-modulator 3, first circulator 5, coupling mechanism 7, second circulator 6, second photodetector 10, second digital signal processing circuit 12, laser instrument 1 constitutes counterclockwise light path of closed loop and signal processing circuit, by the laser instrument 1 that is connected successively, Y splitter 2, second phase-modulator 4, second circulator 6, coupling mechanism 7, first circulator 5, first photodetector 9, first digital signal processing circuit 11, the second combination saw-toothed wave generator 14, second phase-modulator 4 constitutes clockwise light path of closed loop and signal processing circuit, first phase-modulator 3 links to each other with the first combination saw-toothed wave generator 13, and coupling mechanism 7 links to each other with ring resonator 8.

The frequency of being sent by laser instrument is that the light of f is divided into two bundles through the Y splitter, this two-beam enters first circulator 5 and second circulator 6 after making up shift frequency through first phase-modulator 13 and second phase-modulator 14 respectively, be coupled into ring resonator 8 by coupling mechanism 7 again, form counterclockwise and clockwise two light beams, wherein light beam is by second circulator coupling, 6 to second photodetectors 10 counterclockwise, and light beam is coupled to first photodetector 9 by first circulator 5 clockwise.

As shown in Figure 2, first digital signal processing circuit 11 comprises first analog-digital converter 15, first digital lock-in amplifier 16, first digital filter 17, first digitial controller 18 and first digital analog converter 19 that is connected successively.

As shown in Figure 3, second digital signal processing circuit 12 comprises second analog-digital converter 20, second digital lock-in amplifier 21, second digital filter 22, second digitial controller 23 and second digital analog converter 24 that is connected successively.

Shown in Fig. 4,5, the first combination saw-toothed wave generator 13 comprises the first digital saw-toothed wave generator 25, the 3rd digital analog converter 26 that is connected; The second combination saw-toothed wave generator 14 comprises the second digital saw-toothed wave generator 27, the 4th digital analog converter 28 that is connected.

The resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking means comprises the steps:

1) in counterclockwise light path of closed loop and signal processing circuit, be f with the first combination saw-toothed wave generator, 13 generated frequencies ₁And 2f ₁, repetition frequency is the combination sawtooth wave of p, as Fig. 6, thereby makes laser frequency f in preceding half 1/p cycle frequency displacement f take place ₁Become f+f ₁, frequency displacement 2f takes place in half 1/p cycle of back ₁Become f+2f ₁Through counterclockwise light path, second photodetector, 10 output frequencies are the square-wave signal of p, as the left figure of Fig. 7, square wave amplitude I _DoutExpression formula be:

$I_{\mathrm{Dout}}\left(\mathrm{\&Delta;f}\right)=(1-{\mathrm{\&alpha;}}_C)\mathrm{\&rho;}{\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">I</figure-callout>}}_0\&lsqb;\frac{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2}{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2+{(\mathrm{\&Delta;f}-\frac{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}{2})}^2}-\frac{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2}{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0^2+{(\mathrm{\&Delta;f}+\frac{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}{2})}^2}\&rsqb;---\left(1\right)$

Resonance frequency deviation delta f is meant the difference of the resonance frequency of the laser frequency that enters ring resonator 8 and ring resonator itself, and $\mathrm{\&Delta;f}=f+\frac{{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1+{2\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1}{2}-f^{\mathrm{CCW}},$ f ^CCWBe the resonance frequency of counterclockwise light path, C ₀, α _C, ρ is and the irrelevant systematic parameter of modulating frequency.

In clockwise light path of closed loop and signal processing circuit, be f with the second combination saw-toothed wave generator, 14 generated frequencies ₂And f ₁+ f ₂, f ₂Adjustable, and initial value is made as f ₁, repetition frequency is the combination sawtooth wave of p, first photodetector, 9 output square wave such as the right figure of Fig. 7, square wave amplitude I _DoutIdentical with the expression formula of resonance frequency deviation delta f with the clockwise light path of closed loop, but the resonance frequency deviation $\mathrm{\&Delta;f}=f+\frac{{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_2+{\mathrm{<figure-callout\; id="1"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">f</figure-callout>}}_2}{2}-f^{\mathrm{CW}},$ f ^CWIt is the resonance frequency of clockwise light path;

(1) formula is expressed as the polynomial expression of Δ f:

${\mathrm{\&Delta;<figure-callout\; id="4"\; label="f"\; filenames="S2008100591148E00011.png"\; state="\{\{state\}\}">f</figure-callout>}}^4+2\left({{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0}^2-B}^2\right){\mathrm{\&Delta;f}}^2-\frac{4{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0}^2(1-{\mathrm{\&alpha;}}_c)\mathrm{\&rho;}{I}_{0}B}{I_{\mathrm{Dout}0}}\mathrm{\&Delta;f}+{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0}^4+{\mathrm{<figure-callout\; id="4"\; label="B"\; filenames="S2008100591148E00011.png"\; state="\{\{state\}\}">B</figure-callout>}}^4+2{{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="S2008100591148E00021.png"\; state="\{\{state\}\}">C</figure-callout>}}_0}^2\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="S2008100591148E00011.png,S2008100591148E00021.png"\; state="\{\{state\}\}">B</figure-callout>}}^2=0---\left(2\right)$

By equation (2) as can be known, in real number field, this equation has four roots.If Δ f ₀Be a real number root that satisfies equation (2), the then total frequency displacement that need feed back of system: δ f _t=-Δ f ₀Because equation (2) is a transcendental equation, can't directly obtain analytic solution, though the method that can utilize numerical value to iterate obtains the root of equation (2), different I _Dout0Value needs different iterative times, so dsp system is used for will be unable to estimate during this period of time from the input square wave amplitude to the output frequency difference, the real-time performance that detects of the system that can influence.And except that tuning-points, there are two real number roots in equation (2), still needs according to I _DoutWith the relation curve of Δ f these two roots are judged.

The present invention utilizes the relation curve of detector output square wave amplitude and resonance frequency deviation (Δ f), as shown in Figure 8, the output square wave amplitude has been carried out normalization with maximal value among the figure.Near tuning-points (Δ f=0), curve has good linearity, and this is the operation interval of resonance type optical gyroscope, is called approximately linear perform region I; In the both sides of approximately linear perform region I, be the monotony interval of subtraction function character, be called nonlinear area II.When the resonance frequency deviation near zero the time, rate of curve is approximate to be a constant k.After the resonance frequency deviation falls into the approximately linear area I, the present invention utilizes the feedback slope of this constant k as the approximately linear district, by feedback operation repeatedly, respectively with counterclockwise light path and clockwise the frequency lock of light path lock onto the accumulative total frequency difference δ f that is experienced behind the tuning-points to separately tuning-points _tProvide the distance of tuning-points and initial frequency difference, promptly-Δ f ₀Thereby, reach the effect identical with numerical evaluation.

After the square-wave signal that comes out from first photodetector 9 and second photodetector 10 converts digital signal to by digital to analog converter, enter digital signal processing chip DSP, the amplitude that generates with chip internal is ± 1, multiplies each other with the reference square wave of square-wave signal with the frequency homophase, carry out digital phase-locked amplification and separate and be in harmonious proportion behind the digital filtering, obtain reflecting the digital quantity of square-wave signal amplitude.

2) come judgement system original state zone of living in according to the square-wave signal amplitude, introduce criterion 1:|I _Dout2|＞| I _Dout1|, I _Dout1And I _Dout2Be respectively when the resonance frequency deviation be Δ f ₁With Δ f ₂The time demodulation square wave amplitude that obtains, i.e. I _Dout1=I _Dout(Δ f ₁), I _Dout2=I _Dout(Δ f ₂).Δ f ₀Resonance frequency deviation during for system start-up, assignment Δ f ₁=Δ f ₀, feedback frequency difference δ f ₁=-I _Dout1/ k, Δ f ₂=Δ f ₁+ δ f ₁,, then represent frequency difference Δ f if criterion 1 is set up ₁Fall into area I I, feedback frequency difference δ f ₂=-sign (I _Dout1) | Δ f _m|, Δ f here _mBe the free spectrum width FSR of ring resonator 8 and the product of scale-up factor, δ f ₂Introducing be in order when the resonance frequency deviation is positioned at area I I, to enter the unlikely again both sides vibration at area I I of area I, Δ f simultaneously faster ₁=Δ f ₂+ δ f ₂, feed back frequency difference δ f again ₁=-I _Dout1/ k, Δ f ₂=Δ f ₁+ δ f ₁, carry out criterion 1, be false until criterion 1, then Δ f ₁Enter area I, wherein sign (x) is a sign function, when x is timing, be output as+1, when x when negative, be output as-1;

3) enter and carry out tuning-points after the area I and differentiate, introduce criterion 2:|I _Dout1|=0, if criterion 2 is false, then feed back frequency difference δ f ₁=-I _Dout1/ k, Δ f simultaneously ₁=Δ f ₁+ δ f ₁, to set up until criterion 2, EOP (end of program) is locked in tuning-points; When being locked in tuning-points, Shu Chu square wave amplitude value reaches zero in theory, and still, in digital signal processing chip DSP inside, owing to be digital quantity, error is non-vanishing, has finite word length effect.So in the error range that locking allows, can set numeral eps in a small amount,, can think to have reached locking when the square wave amplitude of demodulation during smaller or equal to eps.The process flow diagram of concrete tuning-points track algorithm program is seen Fig. 9.

4) with parameter δ f _tCome the feedback frequency difference of the clockwise light path of accumulative total, to counterclockwise light path, the feedback frequency difference realizes that by the laser frequency f that regulates laser instrument 1 output to clockwise light path, the feedback frequency difference is by regulating the combination sawtooth wave frequency f of the second combination saw-toothed wave generator, 14 outputs ₂Realize that after light path locked tuning-points counterclockwise, when gyro did not rotate, light path also was in resonant condition, f clockwise ₂Initial value is made as f ₁When gyro has the angular velocity of rotation of Ω, light path will no longer be in resonant condition clockwise, need to introduce feedback branch controlled frequency f ₂Size, after each feedback, f ₂=f ₁+ δ f _t, lock onto tuning-points after, the δ f of the gained that adds up _tThe resonance frequency that promptly is clockwise light path and counterclockwise light path is poor, utilizes this resonance frequency difference just can obtain the teetotum tarnsition velocity.Be illustrated in figure 9 as the program flow diagram of tuning-points track algorithm.

Claims (5)

1. resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking apparatus, it is characterized in that by the laser instrument that is connected successively (1), Y splitter (2), first phase-modulator (3), first circulator (5), coupling mechanism (7), second circulator (6), second photodetector (10), second digital signal processing circuit (12), laser instrument (1) constitutes counterclockwise light path of closed loop and signal processing circuit, by the laser instrument that is connected successively (1), Y splitter (2), second phase-modulator (4), second circulator (6), coupling mechanism (7), first circulator (5), first photodetector (9), first digital signal processing circuit (11), the second combination saw-toothed wave generator (14), second phase-modulator (4) constitutes clockwise light path of closed loop and signal processing circuit, first phase-modulator (3) links to each other with the first combination saw-toothed wave generator (13), and coupling mechanism (7) links to each other with ring resonator (8).

2. the frequency feedback tracking locking apparatus of a kind of resonance type optical gyroscope digital closed loop according to claim 1 system is characterized in that described first digital signal processing circuit (11) comprises first analog-digital converter (15), first digital lock-in amplifier (16), first digital filter (17), first digitial controller (18) and first digital analog converter (19) that is connected successively.

3. the frequency feedback tracking locking apparatus of a kind of resonance type optical gyroscope digital closed loop according to claim 1 system is characterized in that described second digital signal processing circuit (12) comprises second analog-digital converter (20), second digital lock-in amplifier (21), second digital filter (22), second digitial controller (23) and second digital analog converter (24) that is connected successively.

4. the frequency feedback tracking locking apparatus of a kind of resonance type optical gyroscope digital closed loop according to claim 1 system is characterized in that the described first combination saw-toothed wave generator (13) comprises the first digital saw-toothed wave generator (25), the 3rd digital analog converter (26) that is connected; The second combination saw-toothed wave generator (14) comprises the second digital saw-toothed wave generator (27), the 4th digital analog converter (28) that is connected.

5. the resonance type optical gyroscope digital closed loop system frequency feedback and tracking locking means that use is installed according to claim 1 is characterized in that comprising the steps:

1) in counterclockwise light path of closed loop and signal processing circuit, be f with first combination saw-toothed wave generator (13) generated frequency ₁And 2f ₁, repetition frequency is the combination sawtooth wave of p, the frequency that laser instrument (1) sends is that the laser of f is subjected to f ₁And 2f ₁Combination frequency modulation, through counterclockwise light path, second photodetector (10) output frequency is the square-wave signal of p, square wave amplitude I _DoutExpression formula be,

$I_{\mathrm{Dout}}\left(\mathrm{\&Delta;f}\right)=(1-{\mathrm{\&alpha;}}_C)\mathrm{\&rho;}{I}_0\&lsqb;\frac{C_0^2}{C_0^2+{(\mathrm{\&Delta;f}-\frac{f_1}{2})}^2}-\frac{C_0^2}{C_0^2+{(\mathrm{\&Delta;f}+\frac{f_1}{2})}^2}\&rsqb;,$ Resonance frequency deviation delta f is meant the difference of the resonance frequency of the laser frequency that enters ring resonator (8) and ring resonator itself, and $\mathrm{\&Delta;f}=f+\frac{f_1+2f_1}{2}-f^{\mathrm{CCW}},$ f ^CCWBe the resonance frequency of counterclockwise light path, C ₀, α _C, the systematic parameter that ρ is and modulating frequency is irrelevant is near zero in the resonance frequency deviation, and square wave amplitude and resonance frequency deviation have monotone increasing, and slope is the linear approximate relationship area I of k, is monotone area II of subtraction function character in the area I both sides; In clockwise light path of closed loop and signal processing circuit, be f with second combination saw-toothed wave generator (14) generated frequency ₂And f ₁+ f ₂, f ₂Adjustable, and initial value is made as f ₁, repetition frequency is the combination sawtooth wave of p, the square wave amplitude I of first photodetector (9) output _DoutIdentical with the expression formula of resonance frequency deviation delta f with counterclockwise light path, but the resonance frequency deviation $\mathrm{\&Delta;f}=f+\frac{f_2+f_1+f_2}{2}-f^{\mathrm{CW}},$ f ^CWIt is the resonance frequency of clockwise light path;

2) criterion 1:|I is introduced in judgement system original state zone of living in _Dout2|＞| I _Dout1|, I _Dout1And I _Dout2Be respectively when the resonance frequency deviation be Δ f ₁With Δ f ₂The time demodulation square wave amplitude that obtains, i.e. I _Dout1=I _Dout(Δ f ₁), I _Dout2=I _Dout(Δ f ₂).Δ f ₀Resonance frequency deviation during for system start-up, assignment Δ f ₁=Δ f ₀, feedback frequency difference δ f ₁=-I _Dout1/ k, Δ f ₂=Δ f ₁+ δ f ₁,, then represent frequency difference Δ f if criterion 1 is set up ₁Fall into area I I, feedback frequency difference δ f ₂=-sign (I _Dout1) | Δ f _m|, Δ f here _mBe the free spectrum width FSR of ring resonator (8) and the product of scale-up factor, δ f ₂Introducing be in order when the resonance frequency deviation is positioned at area I I, to enter the unlikely again both sides vibration at area I I of area I, Δ f simultaneously faster ₁=Δ f ₂+ δ f ₂, feed back frequency difference δ f again ₁=-I _Dout1/ k, Δ f ₂=Δ f ₁+ δ Δ f ₁, carry out criterion 1, be false until criterion 1, then Δ f ₁Enter area I, wherein sign (x) is a sign function, when x is timing, be output as+1, when x when negative, be output as-1;

3) enter and carry out tuning-points after the area I and differentiate, introduce criterion 2:|I _Dout1|=0, if criterion 2 is false, then feed back frequency difference δ f ₁=-I _Dout1/ k, Δ f simultaneously ₁=Δ f ₂+ δ f ₁, to set up until criterion 2, EOP (end of program) is locked in tuning-points;

4) with parameter δ f _tCome the feedback frequency difference of the clockwise light path of accumulative total, to counterclockwise light path, the feedback frequency difference realizes that by the laser frequency f that regulates laser instrument (1) output to clockwise light path, the feedback frequency difference is by regulating the combination sawtooth wave frequency f of second combination saw-toothed wave generator (14) output ₂Realize that after light path locked tuning-points counterclockwise, when gyro did not rotate, light path also was in resonant condition, f clockwise ₂Initial value is made as f ₁When gyro has the angular velocity of rotation of Ω, light path will no longer be in resonant condition clockwise, need to introduce feedback branch controlled frequency f ₂Size, after each feedback, f ₂=f ₁+ δ f _t, lock onto tuning-points after, the δ f of the gained that adds up _tThe resonance frequency that promptly is clockwise light path and counterclockwise light path is poor, utilizes this resonance frequency difference just can obtain the teetotum tarnsition velocity.

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