CN103712634B - The measuring method of optical fibre gyro vibration-magnetic field degree of cross-linking - Google Patents

Abstract

The invention discloses a method for measuring the vibration-magnetic field cross coupling degree of an optical fiber gyroscope. The main test steps of the measurement method disclosed in the present invention are to place the fiber optic gyroscope on a vibrating platform, apply a magnetic field, and measure the output of the fiber optic gyroscope under the action of the radial magnetic field and the output of the fiber optic gyroscope under the cross action of the vibration-magnetic field, respectively, to obtain the diameter The zero bias of the fiber optic gyroscope under the action of the magnetic field and the zero bias of the fiber optic gyroscope under the action of the vibration-magnetic field cross, so as to calculate the magnetic field sensitivity of the fiber optic gyroscope, the vibration-magnetic field cross coupling degree, and evaluate the zero bias stability of the fiber optic gyroscope under the vibration-magnetic field cross action It provides a research basis for further improving the vibration-magnetic field environmental adaptability of fiber optic gyroscopes. The invention can be used to test the magnetic field sensitivity of the fiber optic gyroscope and the magnetic field sensitivity under vibration conditions; it can be used to measure the output characteristics of the fiber optic gyroscope under the cross action of vibration and magnetic field, and evaluate the zero bias stability of the fiber optic gyroscope under the cross action of vibration and magnetic field .

Description

Measuring method of fiber optic gyroscope vibration-magnetic field cross-coupling degree

technical field

The invention relates to a method for measuring the vibration-magnetic field cross-coupling degree of an optical fiber gyroscope.

Background technique

Fiber optic gyroscope is a kind of fiber optic angular velocity sensor based on Sagnac effect. Vibration and magnetic field are two important factors affecting the output accuracy of fiber optic gyroscope. In the fiber optic gyroscope, the fiber optic ring is an important angular velocity sensitive element, which should not be sensitive to linear acceleration. However, in practical applications, when affected by external vibrations, due to the limitations of its own structure, ring-wrapping process, and packaging process, the geometry of the fiber ring may be deformed and cause changes in the stress distribution of the fiber, which in turn leads to A non-reciprocal phase shift occurs in the gyroscope, which causes a phase error in the FOG and thus affects the accuracy of the gyroscope output. Due to the magneto-optic effect, the fiber optic gyroscope produces an additional non-reciprocal phase difference related to the magnetic field. This phase difference changes with the magnitude and direction of the external magnetic field, which reduces the bias stability of the fiber optic gyroscope and directly affects the accuracy of the gyroscope. .

At present, there is no special test method and equipment for the study of fiber optic gyroscope vibration-magnetic field cross-coupling, which brings great inconvenience to experiments and research.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for measuring the vibration-magnetic field cross-coupling degree of the fiber optic gyroscope.

The measurement method of the vibration-magnetic field cross-coupling degree of the fiber optic gyroscope, by measuring the output of the fiber optic gyroscope under static conditions, radial magnetic field, vibration, and vibration-magnetic field cross-action, the fiber optic gyroscope under the vibration-magnetic field cross-action is obtained. The vibration-magnetic field cross-coupling degree is used to evaluate the bias stability of the fiber optic gyroscope under the vibration-magnetic field cross-action.

A method for measuring the degree of vibration-magnetic field cross-coupling of a fiber optic gyroscope, comprising the following steps:

1) The sensitive axis of the fiber optic gyroscope is perpendicular to the vibration table and fixed on the vibration table. The fiber optic gyroscope is located in the center of the Helmholtz coil. The direction of the radial magnetic field generated by the Helmholtz coil is perpendicular to the sensitive axis of the fiber optic gyroscope. The Hall sensor is fixed on the vibration table. The sensitive direction of the Helmholtz sensor is parallel to the direction of the radial magnetic field generated by the Helmholtz coil;

2) The vibrating table is stationary, no radial magnetic field is applied, and the output of the fiber optic gyroscope is measured to obtain the zero bias A ₀ of the fiber optic gyroscope;

3) Apply a radial magnetic field, measure the radial magnetic field B through the Hall sensor, measure the output of the fiber optic gyroscope, and obtain the zero bias A ₀ ' of the fiber optic gyroscope;

4) Calculate the magnetic field sensitivity of the fiber optic gyroscope

5) Remove the radial magnetic field B;

6) Control the vibrating table to vibrate under the condition that the frequency is 10Hz-2KHz and the maximum vibration acceleration is a gravitational acceleration (g), measure the output of the fiber optic gyroscope until the vibration stops, and obtain the fiber optic gyroscope when the vibration maximum acceleration is a gravitational acceleration Zero bias A ₁ ;

7) Apply the radial magnetic field B, repeat the operation of step 6), and obtain the zero bias A ₁ ' of the fiber optic gyroscope when the maximum vibration acceleration is one gravitational acceleration;

8) Remove the radial magnetic field B;

9) Calculate the magnetic field sensitivity of the fiber optic gyroscope under the condition that the vibration frequency is 10Hz‐2KHz and the maximum vibration acceleration is one gravitational acceleration $S_1=\frac{A_1^{\text{'}}-A_1}{B};$

10) Control the frequency of the vibrating table to 10Hz‐2KHz, and the maximum acceleration of vibration is 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, 10g, repeat steps 5) to 9) to obtain a vibration frequency of 10Hz ‐2KHz, the magnetic field sensitivity S ₂ , S ₃ , S ₄ , S ₅ , S ₆ , S ₇ , S ₈ , S ₉ , S ₁₀ ;

11) Substitute S ₀ in step 4) and S _i (i=1,,,,10) in step 9) and step 10) into The vibration frequency is 10Hz-2KHz, the vibration maximum acceleration is 1g, 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, 10g respectively, and the vibration-magnetic field coupling of the fiber optic gyroscope under the condition that the radial magnetic field strength is B Degrees K ₁ , K ₂ , K ₃ , K ₄ , K ₅ , K ₆ , K ₇ , K ₈ , K ₉ , K ₁₀ .

The radial magnetic field B is generated by a Helmholtz coil, and the Helmholtz coil is driven by a current source.

The Hall sensor is located at the center of the Helmholtz coil.

The measurement process should take more than 1 minute to reduce random errors in the measurement process.

The zero bias of the fiber optic gyroscope is the average value of the output data of the fiber optic gyroscope within each measurement time.

The present invention has the beneficial effect compared with prior art:

1) It can be used to test the magnetic field sensitivity of fiber optic gyro and the magnetic field sensitivity under vibration conditions;

2) It can be used to measure the output characteristics of the fiber optic gyroscope under the cross action of vibration-magnetic field, and evaluate the zero bias stability of the fiber optic gyroscope under the cross action of vibration-magnetic field.

Description of drawings

Figure 1 is a schematic top view of the principle of the fiber optic gyro vibration-magnetic field cross-coupling measurement method;

Figure 2 is a schematic front view of the principle of the fiber optic gyroscope vibration-magnetic field cross-coupling degree measurement method;

In the figure: Helmholtz coil 1, vibration table 2, tooling and fiber optic gyroscope 3, Hall sensor 4.

detailed description

The invention provides a method for measuring the vibration-magnetic field cross-coupling degree of a fiber optic gyroscope, which can easily test the influence of the vibration-magnetic field cross action on the output of a fiber optic gyroscope, thereby accelerating the research and evaluation of the fiber optic gyroscope's vibration-magnetic field performance. In the future, the vibration-magnetic field cross-coupling effect of the fiber optic gyroscope will be studied to improve the vibration-magnetic field environmental adaptability of the fiber optic gyroscope, which will lay a good and solid foundation.

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figures 1 and 2, the vibration table is placed horizontally, and the fiber optic gyroscope is fixed on the vibration table through tooling, and the sensitive axis of the fiber optic gyroscope is perpendicular to the surface of the vibration table and upwards. The whole test system is in the radial uniform magnetic field generated by the Helmholtz coil. The vibrating table outputs in the form of frequency sweep, the frequency changes from 10Hz to 20KHz, and the maximum acceleration of vibration increases from 1g (acceleration of gravity) to 10g in turn. Therefore, this test method can respectively measure the output of the fiber optic gyroscope in the radial uniform magnetic field and the output of the vibration-magnetic field cross action, collect and record the data through the computer, and obtain the zero bias of the fiber optic gyroscope in various situations, so as to calculate the output of the fiber optic gyroscope. Magnetic field sensitivity, magnetic field sensitivity under vibration conditions, and vibration-magnetic field cross-coupling.

The measurement method of fiber optic gyroscope vibration-magnetic field cross-coupling degree includes the following steps:

1) The sensitive axis of the fiber optic gyroscope is perpendicular to the vibration table, and the fiber optic gyroscope is fixed on the vibration table by tooling, and the fiber optic gyroscope is located in the center of the Helmholtz coil. After the current source is applied, the Helmholtz coil generates a uniform magnetic field, and the direction of the magnetic field is along the radial direction of the fiber optic gyroscope, that is, perpendicular to the sensitive axis of the fiber optic gyroscope. The Hall sensor is fixed on the vibrating table through tooling, and the sensitive direction of the Hall sensor is parallel to the direction of the radial magnetic field generated by the Helmholtz coil;

2) The vibrating table is stationary, no radial magnetic field is applied, and the output of the fiber optic gyro is measured for more than 1 minute (if it is less than 1 minute, a large random error will be introduced, but if the time is too long, it will affect the measurement efficiency), and the data is collected and recorded by the computer. Obtain the zero bias A ₀ of the fiber optic gyroscope;

3) Turn on the current source that supplies power to the Helmholtz coil, apply a radial magnetic field, measure the size B of the radial magnetic field strength through the Hall sensor, measure the output of the fiber optic gyroscope for more than 1 minute, collect and record the data through the computer, and obtain the radial uniform strength The zero bias A ₀ ' of the fiber optic gyro under the action of a magnetic field;

4) Calculate the magnetic field sensitivity of the fiber optic gyroscope

5) Turn off the current source that supplies power to the Helmholtz coil, and remove the radial magnetic field B;

6) The vibrating table is controlled by a computer to vibrate under the condition of a frequency of 10Hz-2KHz and a maximum vibration acceleration of 1g. The vibration time is set to be greater than 1 minute, and the output of the fiber optic gyroscope is measured. At the same time, the data is collected and recorded by the computer until the vibration stops , get the zero bias A ₁ of the fiber optic gyroscope when the maximum vibration acceleration is 1g;

7) Turn on the current source that supplies power to the Helmholtz coil, apply a radial magnetic field B of the same magnitude as in step 3), repeat the operation in step 6), and obtain the zero of the fiber optic gyroscope when the radial magnetic field strength is B and the maximum vibration acceleration is 1g Offset A ₁ ';

8) Turn off the current source that supplies power to the Helmholtz coil, and remove the radial magnetic field B;

9) Calculate the magnetic field sensitivity of the fiber optic gyroscope under the condition that the vibration frequency is 10Hz‐2KHz and the maximum vibration acceleration is 1g $S_1=\frac{A_1^{\text{'}}-A_1}{B};$

10) The frequency of the vibrating table is controlled by the computer to be 10Hz‐2KHz, and the maximum vibration acceleration is 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, 10g, repeat steps 5) to 9), and measure the vibration frequency as 10Hz‐2KHz, the maximum vibration acceleration is 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, and 10g respectively. The output of the fiber optic gyroscope is collected and recorded by the computer to obtain the zero bias of the fiber optic gyroscope, which is brought into the formula (i=2,...,10), calculate the magnetic field sensitivity S ₂ , S ₃ , S ₄ , S ₅ , S ₆ , S ₇ , S ₈ , S ₉ , S ₁₀ of the fiber optic gyroscope under different vibration conditions;

11) Bring S ₀ in step 4) and S _i (i=1,...,10) in step 9) and step 10) into The vibration frequency is 10Hz-2KHz, the vibration maximum acceleration is 1g, 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, 10g, and the radial magnetic field strength is B. The vibration-magnetic field coupling degree of the fiber optic gyroscope K ₁ , K ₂ , K ₃ , K ₄ , K ₅ , K ₆ , K ₇ , K ₈ , K ₉ , K ₁₀ .

₁₂ ) _The final experimental results _obtained are: _{0.45 %} , _{0.98 %} , _{1.56 %} , _2.03 %, 2.61%, 3.06%, 3.48%, 3.97%, 4.41%, 4.96%.

The radial magnetic field B is generated by the Helmholtz coil, and the Helmholtz coil is driven by a current source. The fiber optic gyroscope is located at the center of the Helmholtz coil, which means that the gyroscope is in a uniform radial magnetic field B when the current source that supplies power to the Helmholtz coil is turned on.

The Hall sensor is located at the center of the Helmholtz coil, and is fixed on the vibrating table through tooling. The sensitive direction of the Hall sensor is parallel to the direction of the magnetic field.

The measurement and collection time of data should be longer than 1 minute to reduce random errors in the measurement process.

The zero bias of the fiber optic gyroscope is the average value of the output data of the fiber optic gyroscope in each measurement time.

Claims (5)

1. A method for measuring the vibration-magnetic field cross-coupling degree of a fiber optic gyroscope, characterized in that, by measuring the output of the fiber optic gyroscope under static conditions, under the action of a radial magnetic field, under the action of vibration and under the cross-action of the vibration-magnetic field, obtain The vibration-magnetic field cross-coupling degree of the fiber optic gyroscope under the vibration-magnetic field cross action, and evaluate the zero-bias stability of the fiber optic gyroscope under the vibration-magnetic field cross action; Include the following steps: 1) The sensitive axis of the fiber optic gyroscope is perpendicular to the vibrating table and fixed on the vibrating table. The fiber optic gyroscope is located in the center of the Helmholtz coil. The direction of the radial magnetic field generated by the Helmholtz coil is perpendicular to the sensitive axis of the fiber optic gyroscope. The sensitive direction of the Helmholtz sensor is parallel to the direction of the radial magnetic field generated by the Helmholtz coil; 2) The vibrating table is static, no radial magnetic field is applied, the output of the fiber optic gyroscope is measured, and the zero bias _A0 of the fiber optic gyroscope is obtained; 3) applying a radial magnetic field, measuring the radial magnetic field B by a Hall sensor, measuring the output of the fiber optic gyroscope, and obtaining the _zero bias A' of the fiber optic gyroscope; 4) Calculate the magnetic field sensitivity of the fiber optic gyroscope 5) Remove the radial magnetic field B; 6) Control the vibrating table to vibrate under the condition that the frequency is 10Hz-2KHz and the maximum vibration acceleration is a gravitational acceleration (g), measure the output of the fiber optic gyroscope until the vibration stops, and obtain the fiber optic gyroscope when the vibration maximum acceleration is a gravitational acceleration Zero bias A ₁ ; 7) apply radial magnetic field B, repeat the operation of step 6), obtain the zero deviation A' of the fiber optic gyroscope when the vibration maximum acceleration is _a gravitational acceleration; 8) Remove the radial magnetic field B; 9) Calculate the magnetic field sensitivity of the fiber optic gyroscope under the condition that the vibration frequency is 10Hz‐2KHz and the maximum vibration acceleration is one gravitational acceleration $S_1=\frac{A_1^{,}-A_1}{B};$ 10) Control the frequency of the vibrating table to 10Hz-2KHz, and the maximum acceleration of vibration is 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, 10g, repeat steps 5) to 9) to obtain a vibration frequency of 10Hz ‐2KHz, the magnetic field sensitivity S ₂ , S ₃ , S ₄ , S ₅ , S ₆ , S ₇ , S ₈ , S ₉ , S ₁₀ ; 11) Substitute S ₀ in step 4) and S _i (i=1,,,,10) in step 9) and step 10) into The vibration frequency is 10Hz-2KHz, the vibration maximum acceleration is 1g, 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, 10g respectively, and the vibration-magnetic field coupling of the fiber optic gyroscope under the condition that the radial magnetic field strength is B Degrees K ₁ , K ₂ , K ₃ , K ₄ , K ₅ , K ₆ , K ₇ , K ₈ , K ₉ , K ₁₀ . 2. The measuring method according to claim 1, wherein the radial magnetic field B is generated by a Helmholtz coil, and the Helmholtz coil is driven by a current source. 3. The measuring method according to claim 1, wherein the Hall sensor is located at the center of the Helmholtz coil. 4. The measuring method according to claim 1, characterized in that, the time of each measuring process should be greater than 1 minute, so as to reduce random errors in the measuring process. 5. The measuring method according to claim 1, characterized in that, the zero bias of the fiber optic gyroscope is the average value of the output data of the fiber optic gyroscope within each measurement time.