Method for accurately testing dead zone of optical fiber gyroscope

Abstract

The invention provides an accurate test method for a dead zone of an optical fiber gyroscope, which comprises the following steps: respectively rotating a sensitive axis of the gyroscope in north and south directions in a direction parallel to a horizontal plane according to a preset rate, judging whether the gyroscope is in the dead zone or not in the rotating process, and obtaining an included angle between the corresponding sensitive axis and the east direction when the gyroscope just rotates out of the dead zone; therefore, the size of the dead zone rotating in the north and south directions is obtained, and the size of the dead zone of the gyroscope is further obtained. The dead zone accurate test method can clearly know how much gyroscope output data is unreal data when the angular rate is small, so that the measurement error caused by the dead zone is compensated through a compensation algorithm, and the problems of control instability and the like of a control system caused by the dead zone problem of the gyroscope can be effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of dead zone detection technology, and in particular to an accurate method for testing the dead zone of a fiber optic gyroscope. Background Technology

[0002] Fiber optic gyroscopes, with their all-solid-state structure, high sensitivity, fast start-up, wide dynamic range, small size, low cost, and long continuous operating time, are highly favored in military and civilian navigation and positioning systems. After decades of development, fiber optic gyroscopes have become the mainstream instrument in the inertial navigation field.

[0003] The dead zone effect of a fiber optic gyroscope refers to the phenomenon where, within a very small range of input angular velocity, the output signal of the fiber optic gyroscope remains zero within that range. This range of input angular velocity is called the dead zone. A comparison of the ideal output curve of a fiber optic gyroscope with and without the dead zone is shown below. Figure 2 As shown in the figure. The dashed line is the ideal output curve without dead time, and the solid line is the output curve with dead time.

[0004] With the trend towards miniaturization and integration of fiber optic gyroscopes, the dead zone effect has become more pronounced or more difficult to suppress. Therefore, accurate testing of the dead zone is of paramount importance in the fields of inertial navigation and high-precision sensing. It is not only one of the key indicators for evaluating gyroscope performance, but also directly affects the reliability, accuracy, and dynamic response capability of the system in practical applications. Summary of the Invention

[0005] This invention provides a method for accurately testing the dead zone of a fiber optic gyroscope, which can solve the technical problems caused by inaccurate dead zone testing, such as the system's inability to sense minute rotations, leading to attitude instability or accumulated errors.

[0006] This invention provides a method for accurately testing the dead zone of a fiber optic gyroscope, the method comprising:

[0007] Place the gyroscope statically on a vibration-damped horizontal platform, set the sensitive axis of the gyroscope to point to the sky and not in the dead zone, collect several digital values ​​output by the gyroscope at a preset frequency within a preset time, and obtain the average value of the digital values ​​output by the gyroscope within the preset time.

[0008] The intrinsic zero bias value of the gyroscope is obtained based on the average value of digital quantities, the Earth's rotational angular velocity, the local geographical latitude, and the gyroscope scaling factor.

[0009] The preset angle is obtained based on the gyroscope's inherent zero bias, the Earth's rotational angular velocity, and the local geographical latitude;

[0010] Fix the gyroscope on the position turntable, set the sensitive axis of the gyroscope to be parallel to the horizontal plane and at a preset angle to due east, at which point the gyroscope is in the dead zone;

[0011] The gyroscope's sensitive axis is rotated northward in a direction parallel to the horizontal plane at a preset rate. During the rotation, the first input angular velocity corresponding to the rotation angle is acquired in real time. Based on the first input angular velocity, the first theoretical output value of the gyroscope is obtained. The gyroscope is then compared with the average digital value to determine whether it is in a dead zone. The angle between the sensitive axis and the east direction when the gyroscope just exits the dead zone is obtained. Based on this angle, the first input angular velocity at this point is also acquired. Finally, the size of the dead zone during the northward rotation is determined based on the first input angular velocity.

[0012] The sensitive axis of the gyroscope is reset to be parallel to the horizontal plane and at a preset angle to due east. At this time, the gyroscope is in the dead zone.

[0013] The gyroscope's sensitive axis is rotated southward in a direction parallel to the horizontal plane at a preset rate. During the rotation, the second input angular velocity corresponding to the rotation angle is acquired in real time. Based on the second input angular velocity, the second theoretical output value of the gyroscope is obtained. The gyroscope is then compared with the average digital value to determine whether it is in a dead zone. The angle between the sensitive axis and the east direction is obtained when the gyroscope just exits the dead zone in the southward rotation. Based on this angle, the second input angular velocity at this point is also obtained. Finally, the size of the dead zone in the southward rotation is determined based on the second input angular velocity.

[0014] The dead zone size of the gyroscope is obtained by using the first input angular velocity to determine the dead zone size for northward rotation and the second input angular velocity to determine the dead zone size for southward rotation.

[0015] Preferably, the inherent zero bias value of the gyroscope is obtained by the following formula:

[0016]

[0017] Among them, Ω 0i =Ω e ·sinφ

[0018] In the formula, B0 is the inherent zero bias of the gyroscope. The Ω value is the average of the digital values, K is the gyroscope scaling factor, and Ω is the gyroscope scaling factor. 0i Ω represents the celestial component of the Earth's local rotational angular velocity. e φ represents the Earth's rotational angular velocity, and φ represents the local geographical latitude.

[0019] Preferably, the preset included angle is obtained by the following formula:

[0020]

[0021] In the formula, α is the preset included angle.

[0022] Preferably, the first input angular velocity is obtained by the following formula:

[0023] Ω N =Ω e ·cosφ·sinα N

[0024] The second input angular velocity is obtained using the following formula:

[0025] Ω S =Ω e ·cosφ·sinα S

[0026] In the formula, Ω N Let α be the first input angular velocity. N Ω represents the rotation angle towards the north. S For the second input angular velocity, α S This is the rotation angle towards the south.

[0027] Preferably, the first theoretical output value of the gyroscope is obtained by the following formula:

[0028] F0=(Ω N +B0)·K

[0029] The second theoretical output value of the gyroscope is obtained using the following formula:

[0030] F0′=(Ω S +B0)·K

[0031] In the formula, F0 is the first theoretical output value of the gyroscope, and F0′ is the second theoretical output value of the gyroscope.

[0032] Preferably, the gyroscope is in the dead zone when rotating northward, provided the following condition is met:

[0033]

[0034] The following condition is met to determine if the gyroscope is in the dead zone when rotating southward:

[0035]

[0036] Preferably, the size of the dead zone rotating northward is obtained by the following formula:

[0037] Ω DN =Ω N +B0

[0038] The size of the dead zone rotating southward is obtained using the following formula:

[0039] ΩDS =Ω S +B0

[0040] In the formula, Ω DN Ω represents the size of the dead zone rotating northward. DS This refers to the size of the dead zone when rotating southward.

[0041] Preferably, the dead zone size of the gyroscope is obtained by the following formula:

[0042] Ω D =|Ω DN |+|Ω DS |

[0043] In the formula, Ω D This represents the dead zone size of the gyroscope.

[0044] By applying the technical solution of this invention, the sensitive axis of the gyroscope is rotated northward and southward respectively in a direction parallel to the horizontal plane at a preset rate. During the rotation, it is determined whether the gyroscope is within the dead zone, and the angle between the sensitive axis and the eastward direction is obtained when the gyroscope just exits the dead zone. This yields the size of the dead zone for northward and southward rotation, and thus the size of the gyroscope's dead zone. This invention's accurate dead zone testing method can clearly determine at what angular rate the gyroscope output data is inaccurate. Furthermore, a compensation algorithm is used to compensate for the measurement error caused by the dead zone, effectively avoiding control instability and other problems caused by the gyroscope dead zone in the control system. Attached Figure Description

[0045] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0046] Figure 1 A flowchart of an accurate testing method for the dead zone of a fiber optic gyroscope according to an embodiment of the present invention is shown;

[0047] Figure 2 A schematic diagram showing the comparison between the ideal output curve of the fiber optic gyroscope detecting angular velocity and the curve with dead zone is presented. Detailed Implementation

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0050] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0051] like Figure 1 As shown, the present invention provides a method for accurately testing the dead zone of a fiber optic gyroscope, the method comprising:

[0052] Place the gyroscope statically on a vibration-damped horizontal platform, set the sensitive axis of the gyroscope to point upwards and not within the dead zone, collect several digital values ​​output by the gyroscope at a preset frequency within a preset time, and obtain the average value of the digital values ​​output by the gyroscope within the preset time; wherein, the preset time can be set to 100s, and the preset frequency can be set to 1Hz.

[0053] The intrinsic zero bias value of the gyroscope is obtained based on the average value of digital quantities, the Earth's rotational angular velocity, the local geographical latitude, and the gyroscope scaling factor.

[0054] The preset angle is obtained based on the gyroscope's inherent zero bias, the Earth's rotational angular velocity, and the local geographical latitude;

[0055] Fix the gyroscope on the position turntable, set the sensitive axis of the gyroscope to be parallel to the horizontal plane and at a preset angle to due east, at which point the gyroscope is in the dead zone;

[0056] The gyroscope's sensitive axis is rotated northward in a direction parallel to the horizontal plane at a preset rate. During the rotation, the first input angular velocity corresponding to the rotation angle is acquired in real time. Based on the first input angular velocity, the first theoretical output value of the gyroscope is obtained. The gyroscope is then compared with the average digital value to determine whether it is in a dead zone. The angle between the sensitive axis and the east direction when the gyroscope just exits the dead zone is obtained. Based on this angle, the first input angular velocity at this point is also acquired. Finally, the size of the dead zone during the northward rotation is determined based on the first input angular velocity.

[0057] The sensitive axis of the gyroscope is reset to be parallel to the horizontal plane and at a preset angle to due east. At this time, the gyroscope is in the dead zone.

[0058] The gyroscope's sensitive axis is rotated southward in a direction parallel to the horizontal plane at a preset rate. During the rotation, the second input angular velocity corresponding to the rotation angle is acquired in real time. Based on the second input angular velocity, the second theoretical output value of the gyroscope is obtained. The gyroscope is then compared with the average digital value to determine whether it is in a dead zone. The angle between the sensitive axis and the east direction is obtained when the gyroscope just exits the dead zone in the southward rotation. Based on this angle, the second input angular velocity at this point is also obtained. Finally, the size of the dead zone in the southward rotation is determined based on the second input angular velocity.

[0059] The dead zone size of the gyroscope is obtained by using the first input angular velocity to determine the dead zone size for northward rotation and the second input angular velocity to determine the dead zone size for southward rotation.

[0060] According to one embodiment of the present invention, the inherent zero bias value of the gyroscope is obtained by the following formula:

[0061]

[0062] Among them, Ω 0i =Ω e ·sinφ

[0063] In the formula, B0 is the inherent zero bias of the gyroscope, in units of (°) / h; Ω is the average value of the digital quantity, in LSB; K is the gyroscope scale factor, in LSB / (°) / s; 0i Ω represents the celestial component of the local Earth's rotational angular velocity, expressed in degrees (°) / h. e φ is the Earth's rotational angular velocity, approximately 15 (°) / h; φ is the local geographical latitude, in (°).

[0064] According to one embodiment of the present invention, the preset included angle is obtained by the following formula:

[0065]

[0066] In the formula, α is the preset included angle.

[0067] According to one embodiment of the present invention, the first input angular velocity is obtained by the following formula:

[0068] Ω N =Ω e ·cosφ·sinα N

[0069] The second input angular velocity is obtained using the following formula:

[0070] Ω S =Ω e ·cosφ·sinα S

[0071] In the formula, Ω N Let α be the first input angular velocity. N The rotation angle is northward, in degrees (°), Ω. S For the second input angular velocity, α S This is the rotation angle towards the south.

[0072] According to one embodiment of the present invention, the first theoretical output value of the gyroscope is obtained by the following formula:

[0073] F0=(Ω N +B0)·K

[0074] The second theoretical output value of the gyroscope is obtained using the following formula:

[0075] F0′=(Ω S +B0)·K

[0076] In the formula, F0 is the first theoretical output value of the gyroscope, in LSB, and F0′ is the second theoretical output value of the gyroscope, in LSB.

[0077] According to one embodiment of the present invention, the gyroscope is considered to be in dead zone when rotating northward, provided that the following formula is satisfied:

[0078]

[0079] The following condition is met to determine if the gyroscope is in the dead zone when rotating southward:

[0080]

[0081] According to one embodiment of the present invention, the size of the dead zone rotating northward is obtained by the following formula:

[0082] Ω DN =Ω N +B0

[0083] The size of the dead zone rotating southward is obtained using the following formula:

[0084] Ω DS =Ω S +B0

[0085] In the formula, Ω DN Ω represents the size of the dead zone rotating northward. DS This refers to the size of the dead zone when rotating southward.

[0086] According to one embodiment of the present invention, the dead zone size of the gyroscope is obtained by the following formula:

[0087] Ω D =|Ω DN |+|Ω DS |

[0088] In the formula, Ω D This represents the dead zone size of the gyroscope.

[0089] In summary, this invention provides an accurate method for testing the dead zone of a fiber optic gyroscope. The gyroscope's sensitive axis is rotated northward and southward parallel to the horizontal plane at a preset rate. During rotation, it is determined whether the gyroscope is within the dead zone, and the angle between the sensitive axis and the eastward direction is obtained when the gyroscope just exits the dead zone. This allows for the determination of the dead zone size for northward and southward rotations, and ultimately, the gyroscope's dead zone size. This accurate dead zone testing method clearly identifies the minimum angular rate at which the gyroscope output data is inaccurate. Furthermore, a compensation algorithm is used to compensate for measurement errors caused by the dead zone, effectively avoiding control instability and other problems in the control system caused by the gyroscope's dead zone.

[0090] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0091] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for accurately testing the dead zone of a fiber optic gyroscope, characterized in that, The method includes: Place the gyroscope statically on a vibration-damped horizontal platform, set the sensitive axis of the gyroscope to point to the sky and not in the dead zone, collect several digital values ​​output by the gyroscope at a preset frequency within a preset time, and obtain the average value of the digital values ​​output by the gyroscope within the preset time. The intrinsic zero bias value of the gyroscope is obtained based on the average value of digital quantities, the Earth's rotational angular velocity, the local geographical latitude, and the gyroscope scaling factor. The preset angle is obtained based on the gyroscope's inherent zero bias, the Earth's rotational angular velocity, and the local geographical latitude; Fix the gyroscope on the position turntable, set the sensitive axis of the gyroscope to be parallel to the horizontal plane and at a preset angle to due east, at which point the gyroscope is in the dead zone; The gyroscope's sensitive axis is rotated northward in a direction parallel to the horizontal plane at a preset rate. During the rotation, the first input angular velocity corresponding to the rotation angle is acquired in real time. Based on the first input angular velocity, the first theoretical output value of the gyroscope is obtained. The gyroscope is then compared with the average digital value to determine whether it is in a dead zone. The angle between the sensitive axis and the east direction when the gyroscope just exits the dead zone is obtained. Based on this angle, the first input angular velocity at this point is also acquired. Finally, the size of the dead zone during the northward rotation is determined based on the first input angular velocity. The sensitive axis of the gyroscope is reset to be parallel to the horizontal plane and at a preset angle to due east. At this time, the gyroscope is in the dead zone. The gyroscope's sensitive axis is rotated southward in a direction parallel to the horizontal plane at a preset rate. During the rotation, the second input angular velocity corresponding to the rotation angle is acquired in real time. Based on the second input angular velocity, the second theoretical output value of the gyroscope is obtained. The gyroscope is then compared with the average digital value to determine whether it is in a dead zone. The angle between the sensitive axis and the east direction is obtained when the gyroscope just exits the dead zone in the southward rotation. Based on this angle, the second input angular velocity at this point is also obtained. Finally, the size of the dead zone in the southward rotation is determined based on the second input angular velocity. The dead zone size of the gyroscope is obtained by using the first input angular velocity to determine the dead zone size for northward rotation and the second input angular velocity to determine the dead zone size for southward rotation.

2. The method according to claim 1, characterized in that, The intrinsic zero bias value of the gyroscope is obtained by the following formula: Among them, Oh 0i =Oh e ·sinφ In the formula, B0 is the inherent zero bias of the gyroscope. The Ω value is the average of the digital values, K is the gyroscope scaling factor, and Ω is the gyroscope scaling factor. 0i Ω represents the celestial component of the Earth's local rotational angular velocity. e φ represents the Earth's rotational angular velocity, and φ represents the local geographical latitude.

3. The method according to claim 1, characterized in that, The preset included angle is obtained using the following formula: In the formula, α is the preset included angle.

4. The method according to claim 1, characterized in that, The first input angular velocity is obtained using the following formula: Oh N =Oh e ·cosφ·sinα N The second input angular velocity is obtained using the following formula: Oh S =Oh e ·cosφ·sinα S In the formula, Ω N Let α be the first input angular velocity. N Ω represents the rotation angle towards the north. S For the second input angular velocity, α S This is the rotation angle towards the south.

5. The method according to claim 1, characterized in that, The first theoretical output value of the gyroscope is obtained using the following formula: F0<(Ω N +B0)·K The second theoretical output value of the gyroscope is obtained using the following formula: F0′=(Ω S +B0)·K In the formula, F0 is the first theoretical output value of the gyroscope, and F0′ is the second theoretical output value of the gyroscope.

6. The method according to claim 1, characterized in that, The following condition is met to determine if the gyroscope is in the dead zone when rotating northward: The following condition is met to determine if the gyroscope is in the dead zone when rotating southward:

7. The method according to claim 1, characterized in that, The size of the dead zone rotating northward can be obtained using the following formula: Oh DN =Oh N +B0 The size of the dead zone rotating southward is obtained using the following formula: Oh DS =Oh S +B0 In the formula, Ω DN Ω represents the size of the dead zone rotating northward. DS This refers to the size of the dead zone when rotating southward.

8. The method according to claim 1, characterized in that, The dead zone size of the gyroscope can be obtained using the following formula: Oh D =|Ω DN |+|Ω DS | In the formula, Ω D This represents the dead zone size of the gyroscope.

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