CN102636183B - Quadratic overload term test method for flexible gyroscope based on optical fiber monitoring and centrifuge with two-axis turntable - Google Patents

Abstract

The invention discloses a method for testing the secondary overload item of a flexible gyroscope based on optical fiber monitoring and a two-axis turntable centrifuge, belonging to the technical field of inertia. In the test method described above, the fiber optic gyroscope and the flexible gyroscope are first installed on a centrifuge with a two-axis turntable, the flexible gyroscope and the fiber optic gyroscope are powered on, and after the preheating is stable, the static output data is collected; the centrifuge and the two-axis follow-up The outer rotary table and the inner rotary table in the turntable rotate synchronously. After the speed is stable, the overload output data is collected; finally, the secondary overload item coefficient is calculated. The invention has the advantage of being able to calibrate the relationship between the quadratic term of the specific force sensitive error included in the static drift model of the flexible gyroscope and the environmental overload acceleration, and can establish a quadratic polynomial model of the specific force sensitive error term to calculate and confirm the deflection Provide a test plan for the influence of the nonlinear error of the gyroscope on the system error.

Description

Testing method for secondary overload item of flexible gyroscope based on optical fiber monitoring and double-axis turntable centrifuge

technical field

The invention belongs to the technical field of inertia, and in particular relates to a method for testing the secondary overload item of a flexible gyroscope based on optical fiber monitoring and a two-axis turntable centrifuge.

Background technique

The flexible gyroscope is a mechanical two-degree-of-freedom gyroscope. The motor shaft of its driving motor drives the rotor to rotate at high speed through a flexible joint. As shown in Figure 1, the flexible joint includes two pairs of mutually orthogonal Flexible connecting shaft and a gimbal. Since its inception, flexible gyroscopes have been widely used in various navigation, guidance and control systems.

In practical applications, there are drift errors in the angular velocity measurement value of the flexible gyroscope due to various internal and external factors, generally composed of static drift error, dynamic drift error and random drift error, among which the linear motion caused The static drift error is the main part of the drift error of the flexible gyro, and it is also the main factor of the error of the flexible strapdown inertial navigation system. The static drift error mathematical model of the flexible gyroscope includes the drift error term which is not sensitive to contrast force and the drift error term which is sensitive to contrast force.

Generally, the static error model of a flexible gyroscope can be expressed as:

${\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}$

$<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}$

$<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xy</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; yz</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xz</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}$

$<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xx</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; yy</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; zz</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; z</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Among them, ω _d ——the drift rate error of the gyroscope, unit: °/h;

K _d ——constant drift coefficient, independent of specific force, unit: °/h;

K _x , K _y , K _z —coefficient of specific force sensitivity, unit: (°/h)/g;

K _xx , K _yy , K _zz — coefficient of specific force square sensitive term, unit: (°/h)/g ² ;

K _xy , K _yz , K _xz —coefficient of specific force product sensitive term, unit: (°/h)/g ² ;

a _x , a _y , a _z —— specific force along the corresponding axis of the gyroscope, unit: g;

The existing flexible gyroscope or flexible inertial group calibration adopts a static multi-position calibration method, using a turntable to make the flexible gyroscope face a certain direction, and taking the local earth rotation angular velocity ω _e and gravitational acceleration g ₀ as standard input, through The error term coefficient of the flexible gyroscope is calculated by joint solution of multiple equations. The static multi-position calibration method can obtain the constant value drift coefficient and the specific force sensitivity coefficient of the flexible gyroscope under the environment of 0-1g, and it is considered that the coefficient remains unchanged under the high overload environment. However, when flexible gyroscopes or flexible inertial sets are used in large overload environments such as missiles, the navigation accuracy is often far from the theoretical calculation value after compensation based on the ground multi-position static calibration results. After a detailed analysis, relevant technical personnel believe that the reason for this phenomenon may be that the coefficient of the specific force sensitive item of the flexible gyroscope has changed under a large overload environment.

If the corresponding relationship between the specific force sensitive term coefficient (including the first-order term coefficient and the second-order term coefficient) of the two-degree-of-freedom flexible gyroscope and the environmental overload can be accurately obtained through the large overload test on the ground, the flexibility can be accurately compensated in actual use. The specific force sensitive error of the gyroscope can improve the actual navigation performance of the flexible strapdown inertial navigation system, which has very important military significance and practical value.

The invention patent of authorized notification number CN 101377422 B discloses a flexible gyroscope static drift error model optimal twenty-four position calibration method, which is to install the flexible gyroscope on the three-axis position rate turntable and adopt discrete D-most The optimal design and construction method is used for design, and twenty-four spatial position orientations are selected from the entire test space as the orientation of the gyro coordinate system and tested. Compared with the optimal eight-position method, the optimal twenty-four-position test can not only calibrate the acceleration irrelevant item and the first-order related item of acceleration, but also obtain the drift coefficient of the second-order related item of acceleration.

The optimal 24-position calibration method described above is essentially the same as the traditional static multi-position test method. It can only use the gravitational field as the environmental overload excitation. Although the effect is better than that of the 8-position, the obtained results can only be expressed in a 1g environment. , the accurate value of the calibration coefficient cannot be obtained in a large overload environment exceeding 1g. In the environment of no more than 1g, it is actually difficult to effectively distinguish the quadratic related item of acceleration from the device noise, so the reliability of the result is not high.

Contents of the invention

The purpose of the present invention is to use a centrifuge with a dual-axis turntable to simulate a large overload environment in the fiber optic gyro monitoring mode, and to test the relationship between the quadratic term coefficient of the specific force sensitivity error of the flexible gyro and the environmental overload acceleration, which is the flexible gyro overload Non-linear error testing and modeling provide testing means.

The present invention provides a dual-freedom overload input for the flexible gyroscope through optical fiber monitoring + centrifuge experiment with a double-axis turntable; adopts the Fourier series decomposition method to obtain the quadratic term coefficient of the specific force sensitive error of the flexible gyroscope, and the specific test method The steps are as follows:

Step 1: Install the fiber optic gyroscope and flexible gyroscope on the centrifuge:

The centrifuge is equipped with a two-axis follow-up turntable, and the two-axis follow-up turntable includes an inner turntable and an outer turntable installed on the rotating table of the centrifuge, and the rotating shaft of the outer turntable is connected to the centrifuge The rotating shafts are parallel, the inner rotating table is fixedly connected to the outer rotating table, the rotating axis of the inner rotating table is perpendicular to the rotating axis of the outer rotating table, the flexible gyroscope and the fiber optic gyroscope are fixedly installed on the inner rotating table; before the test, adjust the rotation axis of the outer rotating table The table and the rotating table of the centrifuge are parallel to the horizontal plane, and then the flexible gyro and the single-axis fiber optic gyroscope are installed on the table of the inner rotating table; when installing, the sensitive axis Y of the flexible gyroscope is parallel to the rotation axis of the inner rotating table, and the flexural The X-axis of the sensitive axis of the gyroscope is perpendicular to the rotation axis of the external rotating table, and the sensitive axis of the fiber optic gyroscope is parallel to the X-axis of the flexible gyroscope; the power supply and signal of the flexible gyroscope are connected through the slip ring of the double-axis follow-up turntable and the centrifuge to the power supply and data acquisition computer;

Step 2: Control the centrifuge and the dual-axis follow-up turntable at their zero positions respectively through the control interface and keep them still. At this time, the sensitive axis X of the flexible gyroscope points to the local geographical north, the Y axis is horizontal, and the rotation reference axis Z up. At this time, both the sensitive axis of the fiber optic gyroscope and the X-axis of the flexible gyroscope point to the local geographical north. Power on the flexible gyro and fiber optic gyro 4, and warm up and stabilize for 10 minutes;

Step 3: Open the acquisition software in the data acquisition computer to start collecting the static output data of the flexible gyroscope and fiber optic gyroscope;

Step 4: Make the centrifuge rotate at an angular velocity ω _t =5ω ₀ , the outer rotary table in the two-axis follow-up turntable rotates synchronously at an angular velocity -ω _t , and the inner rotary table rotates at an angular velocity ω ₀ . It is assumed that the synchronization error caused by the start-up process is small and negligible. The environmental overload acceleration amplitude felt by the sensitive axis of the flexible gyro is:

${\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; 5</span>}\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 180</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}$

Among them, R is the distance from the reference axis of the flexible gyroscope to the rotation axis of the centrifuge, and _g0 is the local standard gravitational acceleration;

Step 5: After the speed of the centrifuge and the dual-axis follow-up turntable is stable, collect the overload output data of the X-axis and Y-axis of the flexible gyroscope;

Step 6: Repeat steps 4 and 5, set different angular velocities ω ₀ = ω _i of the inner rotating table, i=1, 2, 3,...n, and obtain the torsion under different environmental overload accelerations a _i Overload output data of gyroscope and fiber optic gyroscope;

Step 7: After the test is completed, the centrifuge and the dual-axis follow-up turntable are shut down, data collection is stopped, and the system is powered off;

Step 8: Calculate the coefficient of the secondary overload term.

The advantages of the present invention are:

The present invention can calibrate the relationship between the quadratic term of the specific force sensitive error contained in the static drift model of the flexible gyroscope and the environmental overload acceleration, and can establish a quadratic polynomial model of the specific force sensitive error term. The impact of linearity error on system error provides a test plan.

Description of drawings

Fig. 1 is a structural schematic diagram of a flexible gyro mechanical rotor and a flexible joint in the prior art;

Fig. 2 is a schematic structural view of a centrifuge with a dual-axis follow-up turntable used in the present invention.

Detailed ways

The test method for the secondary overload item of the flexible gyroscope based on optical fiber monitoring and a two-axis turntable centrifuge provided by the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

The invention provides a method for testing the secondary overload item of a flexible gyroscope based on optical fiber monitoring and a two-axis turntable centrifuge. The steps of the specific test method are as follows:

The first step: the installation of fiber optic gyroscope and flexible gyroscope.

The main equipment used in this test is a centrifuge with a two-axis follow-up turntable. As shown in Figure 2, the described two-axis follow-up turntable includes an inner turntable 2 and an outer turntable 3 installed on the centrifuge turntable 1, and the rotating shaft of the outer turntable 3 is connected to the rotating shaft of the centrifuge 7. Parallel, the inner rotating table 2 is fixedly connected on the outer rotating table 3, the rotation axis of the inner rotating table 2 is perpendicular to the rotating axis of the outer rotating table 3, and the flexible gyroscope 5 and the fiber optic gyroscope 4 are fixedly installed on the inner rotating table 2 through the tooling 6. Before the test, use a horizontal calibration instrument to adjust the table top of the outer rotating table 3 and the rotating table 1 of the centrifuge to be parallel to the horizontal plane, and then install the flexible gyroscope 5 and the single-axis fiber optic gyroscope 4 on the table of the inner rotating table 2 through the tooling 6 . During installation, the sensitive axis Y axis of the flexible gyroscope 5 is parallel to the rotational axis of the inner rotary table 2, the sensitive axis X axis of the flexible gyroscope 5 is perpendicular to the rotational axis of the outer rotary table 3, and the sensitive axis of the fiber optic gyroscope 4 is parallel to the flexible axis of the flexible gyroscope. The X axis of the gyro 5 is parallel. The power supply and signal of the flexible gyroscope 5 are connected to the power supply and data acquisition computer through the biaxial follow-up turntable and the slip ring of the centrifuge.

Step 2: Control the centrifuge 7 and the two-axis follow-up turntable at their zero positions respectively through the control interface and keep them still. At this time, the sensitive axis X of the flexible gyroscope 5 points to the local geographical north, the Y axis is horizontal, and the rotation reference Axis Z is up. At this time, both the sensitive axis of the fiber optic gyroscope and the X-axis of the flexible gyroscope point to the local geographical north. Power on the flexible gyro 5 and the fiber optic gyro 4, and warm up and stabilize for 10 minutes;

Step 3: Open the acquisition software in the data acquisition computer to start collecting the static output data of the flexible gyroscope 5 and the fiber optic gyroscope 4, and the acquisition time is not less than 5 minutes;

Step 4: Make the centrifuge 7 rotate at an angular velocity ω _t = 5ω ₀ (unit: °/s), and the outer rotating table 3 in the dual-axis follow-up turntable rotates at an angular velocity -ω _t (unit: °/s), internally rotating Stage 2 rotates synchronously with angular velocity ω ₀ . It is assumed that the synchronization error caused by the start-up process is small and negligible. The environmental overload acceleration amplitude felt by the sensitive axis of the flexible gyro is:

${\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; 5</span>}\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 180</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}$

Wherein, R is the distance from the flexible gyro rotation reference axis (Z axis) to the centrifuge rotation axis, unit: m; g ₀ is the local standard gravitational acceleration, unit m/s ² ;

Step 5: After the centrifuge 7 and the two-axis follow-up turntable rotate at a stable speed, collect the overload output data of the X-axis and Y-axis of the flexible gyroscope for 15 minutes;

Step 6: Repeat step 4 and step 5, set different angular velocities ω ₀ =ω _i of the inner rotary table 2, i=1, 2, 3,...n, and obtain the angular velocity under different environmental overload accelerations a _i Overload output data of flexible gyroscope and fiber optic gyroscope, i=1, 2, 3,...n;

Step 7: After the test is completed, the centrifuge 7 and the two-axis follow-up turntable are shut down, data collection is stopped, and the system is powered off;

Step 8: Calculate the coefficient of the secondary overload item:

(1) Calculate the average value of the static output data of the X-axis of the flexible gyroscope and the fiber optic gyroscope under the initial static state collected;

(2) The output data of the X-axis of the flexible gyroscope and the output data of the fiber optic gyroscope under different environmental overload accelerations collected are respectively subtracted from the average value of the initial static output data of the corresponding axis;

(3) Calculate the X-axis output residual of the flexible gyroscope according to the following formula, where the scaling factors of the flexible gyroscope and fiber optic gyroscope have been obtained through calibration tests:

(4) For the data D _ij (X) of the flexible gyroscope residual error at different overload acceleration a _i , intercept the whole cycle data, the cycle The number of intercepted data N _i satisfies , where t is the sampling period, m takes an integer of 600, is the data collection time under the overload acceleration a _i , i=1, 2, 3,...n; j=1, 2...n.

(5) Perform Fourier series operation on the intercepted X-axis residual data of the flexible gyroscope in each overload acceleration segment, and obtain the Fourier series p-order sine harmonic coefficient A _pxi and p-order cosine harmonic coefficient B _pxi respectively (p = 1, 2, 3, ... 12);

${\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; pxi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&pi;p</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 180</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>$ ${\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; pxi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&pi;p</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 180</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$

(6) Calculate the coefficient of the secondary overload term of the flexible gyroscope under different overload accelerations:

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xxi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xyi</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 9</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xzi</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; yzi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 9</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; zzi</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Make a list of K _xxi , K _xyi , K _xzi , K _yzi , K _zzi (i=1, 2, 3,...n) and the corresponding environmental overload acceleration a _i . In application, the flexibility can be obtained by looking up the table The value of the gyro specific force sensitive secondary overload term coefficient under different environmental overload accelerations.

Through the above test method, the accurate value of the calibration coefficient of the flexible gyroscope in a large overload environment exceeding 1g can be obtained. According to the relationship between the quadratic term of the specific force sensitivity error contained in the static drift model of the calibrated flexible gyroscope and the environmental overload acceleration , the quadratic polynomial model of the specific force sensitive error term can be established to provide a test plan for calculating and confirming the influence of the nonlinear error of the flexible gyroscope on the system error.

Claims (2)

1. The method for testing the secondary overload item of the flexible gyroscope based on optical fiber monitoring and a two-axis turntable centrifuge, characterized in that: Step 1: Install the fiber optic gyroscope and flexible gyroscope on the centrifuge: The centrifuge is equipped with a two-axis follow-up turntable, and the two-axis follow-up turntable includes an inner turntable and an outer turntable installed on the rotating table of the centrifuge, and the rotating shaft of the outer turntable is connected to the centrifuge The rotating shafts are parallel, the inner rotating table is fixedly connected to the outer rotating table, the rotating axis of the inner rotating table is perpendicular to the rotating axis of the outer rotating table, the flexible gyroscope and the fiber optic gyroscope are fixedly installed on the inner rotating table; before the test, adjust the rotation axis of the outer rotating table The table and the rotating table of the centrifuge are parallel to the horizontal plane, and then the flexible gyro and the single-axis fiber optic gyroscope are installed on the table of the inner rotating table; when installing, the sensitive axis Y of the flexible gyroscope is parallel to the rotation axis of the inner rotating table, and the flexural The X-axis of the sensitive axis of the gyroscope is perpendicular to the rotation axis of the external rotating table, and the sensitive axis of the fiber optic gyroscope is parallel to the X-axis of the flexible gyroscope; the power supply and signal of the flexible gyroscope are connected through the slip ring of the double-axis follow-up turntable and the centrifuge to the power supply and data acquisition computer; Step 2: Control the centrifuge and the dual-axis follow-up turntable at their zero positions respectively through the control interface and keep them still. At this time, the sensitive axis X of the flexible gyroscope points to the local geographical north, the Y axis is horizontal, and the rotation reference axis Z Upward, the sensitive axis of the fiber optic gyroscope and the X axis of the flexible gyroscope point to the local geographical north, the flexible gyroscope and the fiber optic gyroscope are powered on, and the preheating is stable; Step 3: Open the acquisition software in the data acquisition computer to start collecting the static output data of the flexible gyroscope and fiber optic gyroscope; Step 4: Make the centrifuge rotate at an angular velocity ω _t = 5ω ₀ , the outer rotary table in the two-axis follow-up turntable rotates at an angular velocity -ω _t , and the inner rotary table rotates at an angular velocity ω ₀ synchronously, and the sensitive axis of the flexible gyroscope feels The environmental overload acceleration amplitude is: ${\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 5</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 180</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}$ Among them, R is the distance from the reference axis of the flexible gyroscope to the rotation axis of the centrifuge, and _g0 is the local standard gravitational acceleration; Step 5: After the speed of the centrifuge and the dual-axis follow-up turntable is stable, collect the overload output data of the X-axis and Y-axis of the flexible gyroscope; Step 6: Repeat steps 4 and 5, set different angular velocities ω ₀ ＝ω _i of the inner rotating table, i=1, 2, 3,...n, and obtain the torsion under different environmental overload accelerations a _i Overload output data of gyroscope and fiber optic gyroscope; Step 7: After the test is completed, the centrifuge and the dual-axis follow-up turntable are shut down, data collection is stopped, and the system is powered off; Step 8: Calculate the coefficient of the secondary overload term. 2. the flexible gyro secondary overload item test method based on optical fiber monitoring and biaxial turntable centrifuge according to claim 1, is characterized in that: the secondary overload item coefficient described in the eighth step is specifically: (1) Calculate the average value of the static output data of the X-axis of the flexible gyroscope and the fiber optic gyroscope under the initial static state collected; (2) The output data of the X-axis of the flexible gyroscope and the output data of the fiber optic gyroscope under different environmental overload accelerations collected are respectively subtracted from the average value of the initial static output data of the corresponding axis; (3) Calculate the X-axis output residual of the flexible gyroscope according to the following formula, where the scaling factors of the flexible gyroscope and fiber optic gyroscope have been obtained through calibration tests: (4) For the data D _ij (X) of the flexible gyroscope residual error at different overload acceleration a _i , intercept the whole cycle data, the cycle The number of intercepted data N _i satisfies Where t is the sampling period, m takes an integer of 600, is the data acquisition time under the overload acceleration a _i , i=1,2,3,...n; j=1,2...; (5) Perform Fourier series operation on the intercepted X-axis residual data of the flexible gyroscope in each overload acceleration segment, and obtain the Fourier series p-order sine harmonic coefficient A _pxi and p-order cosine harmonic coefficient B _pxi respectively : ${\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; pxi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&pi;p</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 180</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; pxi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&pi;p</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 180</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}$ Among them, p=1,2,3,...12; (6) Calculate the coefficient of the secondary overload term of the flexible gyroscope under different overload accelerations: ${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xxi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ ${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xyi</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 9</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ ${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; xzi</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ ${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; yzi</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 9</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ ${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; zzi</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; B</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}\mathrm{<span\; class="notranslate">\; xi</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ According to the corresponding relationship between K _xxi , K _xyi , K _xzi , K _yzi , K _zzi and the corresponding environmental overload acceleration a _{i above} , the values of the secondary overload term coefficients of the specific force sensitivity of the flexible gyroscope under different environmental overload accelerations are obtained.