A method for coiling a fiber tail of a fiber-optic gyroscope with minimum axial twisting

Abstract

The application discloses a minimum axial torsion coiling method for fiber tail of an optical fiber gyro, which comprises the following steps: first, vertically lifting the fiber tail and approaching a smooth cylinder from one side; second, sticking the upper end of the fiber tail to the surface of the cylinder, keeping the position of the sticking part and rotating the cylinder; third, stopping the rotation of the cylinder when the remaining fiber tail reaches the requirement, and ring-pointing and curing the fiber tails on both sides; fourth, taking off the fiber tail, turning over one side of the fiber tail, and combining the two fiber tail rings and the connecting fiber tail in the middle into one fiber tail ring; and fifth, putting the combined fiber tail ring into the mounting cavity and winding the remaining fiber tails on both sides into the mounting cavity and fixing them by point gluing. The application solves the problem of coiling defects of the fiber tail, such as the rotation and torsion of the fiber along the light axis, excessive stress, cracks and damage, caused by the axial torsion of the fiber tail for many times due to the difference in the operation habits of workers and the non-standard operation in manual coiling of the fiber tail, and further improves the consistency, reliability and long-term performance stability of the coiling of the fiber tail of the optical fiber gyro.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic gyroscope pigtail assembly. More specifically, it relates to a method for winding a closed-loop fiber optic gyroscope pigtail with minimal axial twist. Background Technology

[0002] Fiber optic gyroscopes are precision inertial navigation instruments integrating opto-mechatronics. They are widely used in guided weapons such as tactical missiles. As a core guidance component for various missile types, fiber optic gyroscopes are in high demand and require high navigation accuracy. This necessitates efficient and reliable optical path assembly. The optical path assembly process mainly involves sequentially splicing the pigtails of the optoelectronic components. To allow sufficient pigtail slack for splicing and subsequent instrument repair, the pigtails at each end of the optoelectronic device are typically left with a length of 400–1000 mm. Therefore, after splicing, a large pigtail loop with a circumference of approximately 800–2000 mm is formed. The large pigtail loop is then manually coiled into multiple turns by a fiber coiling worker and placed into the mounting cavity for fixation and encapsulation.

[0003] Because a large pigtail loop forms a closed loop after being connected to other hardware, it is often called a closed-loop pigtail. Similarly, a pigtail with only one end connected to other components and the other end free is called an open-loop pigtail. The winding difficulty of a closed-loop pigtail is much greater than that of an open-loop pigtail. Winding a large closed-loop pigtail with optical components connected to both ends into a multi-turn loop inevitably requires axial torsion of the pigtail. Since pigtails are brittle materials, excessive axial torsion can cause microcracks, severely affecting the transmission power and service life of the pigtail. Therefore, the overall axial torsional stress level of the pigtail loop is a key factor determining the quality of the pigtail assembly. Due to different worker operating habits and the lack of specific winding process parameters, manually wound pigtails often suffer from problems such as high axial torsional stress, poor consistency, inconsistent coil diameter, loose coils, and edges not adhering to the wall. This leads to uneven stress distribution in the pigtails, reducing the transmission power and lifespan of the pigtails. This is one of the reasons why the accuracy of fiber optic gyroscopes in my country is generally lower than that abroad. Therefore, it is necessary to propose a minimum axial torsional winding method for closed-loop pigtails in fiber optic gyroscopes. Summary of the Invention

[0004] The purpose of this invention is to provide a method for winding fiber optic gyroscope pigtails with minimal axial torsion, thereby reducing the torsional stress of manually winding pigtails and improving the consistency and reliability of pigtail ring winding.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for minimizing axial torsion winding of fiber optic gyroscope pigtails. First, the spliced ​​large pigtail loop is vertically pulled up to form an anti-catenary spatial structure. A smooth cylinder is then approached from the side of the anti-catenary pigtail loop, with its top arc section fitting against the smooth cylinder surface, forming an intersecting line on the cylinder surface. The two lines on the left and right sides of the large pigtail loop remain vertical. Next, the intersecting section of the pigtail is kept relatively stationary with respect to the cylinder, and the cylinder is rotated in the direction of rotation for winding the large pigtail loop, using the cylinder's axis as the rotation axis. As the cylinder rotates, the remaining portion of the large pigtail loop gradually decreases. When the length of the vertical pigtails on both sides is reduced to a specific value... When the value is set, stop the rotation of the cylinder. The spatial orientation of the closed-loop pigtail on the cylinder is that there is a pigtail loop on the left and right sides, which are connected by a cross-shaped pigtail in the middle. Apply glue to the two pigtail loops. After curing, slide the pigtail out along the axis of the smooth cylinder. Flip the fiber loop on one side relative to the fiber loop on the other side. After flipping, rotate along the axis of the fiber loop until the middle section of the pigtail fits the fiber and is wrapped into a pigtail loop of equal diameter. At this point, a closed-loop large pigtail loop is wound into a multi-turn fiber loop. Put this fiber loop into the cavity, and at the same time, put the remaining pigtails on the left and right sides into the installation cavity. This completes the minimum axial torsion winding of the closed-loop pigtail of the fiber optic gyroscope.

[0007] The aforementioned method for minimum axial twisting of fiber optic gyroscope pigtails further includes the following steps:

[0008] Step 1: Using the middle part of the fused closed-loop pigtail as the pickup point, lift the closed-loop pigtail vertically and use a smooth cylinder to approach the pickup point from one side of the pigtail.

[0009] Step 2: Attach the uppermost section of the pigtail to the smooth surface of the cylinder, maintain its position on the cylinder surface, and rotate the cylinder in the direction of the pigtail winding.

[0010] Step 3: When the vertical pigtail length at the bottom of the cylinder reaches the required length, stop rotating the cylinder. At this time, apply glue to the two pigtail rings so that they do not fall apart after being removed.

[0011] Step 4: Slide out two pigtail loops and the connecting pigtail in the middle section along the same axial direction of the cylinder. Place the two pigtail loops horizontally along the axis. Flip one of the pigtail loops so that the connecting pigtail in the middle fits into the flipped pigtail loop, forming a half-circle pigtail loop of equal diameter. Then merge the two pigtail loops on the left and right into one pigtail loop.

[0012] Step 5: Place the merged pigtail ring into the gyroscope mounting cavity, and then wind the remaining pigtails on both sides into the cavity. Finally, apply a small amount of curing adhesive to fix all the pigtails in the mounting cavity.

[0013] In step 1 of the fiber optic gyroscope pigtail minimum axial twisting winding method, the spatial orientation of the smooth cylinder is as follows: the axis of the cylinder is horizontal and tangent to the vertical plane where the pulled-up closed-loop pigtail is located, and the diameter of the cylinder is the maximum inscribed circle diameter of the gyroscope disk mounting cavity minus 1 to 1.5 mm.

[0014] In step 2, the pigtail is attached to the surface of the cylinder and its position on the surface is to restrict the degree of freedom of this position so that the pigtail below can be rolled up, and its length should be half the circumference of the cylinder. This is to ensure that after the pigtail ring is flipped over, there is no need to make the pigtail ring rotate axially, so that this half-circle pigtail can be attached to the pigtail ring exactly.

[0015] In step 3, the requirement that the vertical pigtail length meets the requirement means that the length of the vertical pigtails on the left and right sides below the smooth cylinder reaches half the circumference of the cylinder. This length setting is also to ensure that the vertical pigtails on both sides are subsequently merged into a complete loop.

[0016] In step 4, flipping one side of the pigtail ring means rotating it 180 degrees towards the other pigtail ring, with the vertical pigtail below the pigtail ring to be flipped as the axis; merging the two pigtail rings into one pigtail ring means translating the flipped pigtail ring so that the two pigtail rings are coaxial and close together, treating them as one pigtail ring.

[0017] In step 5, the phrase "the remaining pigtails are wound into the cavity" specifically refers to the two remaining pigtails being coiled in opposite directions to form a pigtail loop. The phrase "applying a small amount of curing adhesive" specifically refers to bonding the two pigtail loops and the pigtail loop together with adhesive.

[0018] The beneficial effects of the fiber optic gyroscope pigtail winding method of the present invention with minimal axial twisting are as follows:

[0019] The fiber optic gyroscope pigtail winding method proposed in this invention can avoid assembly defects caused by excessive axial twisting of the pigtail due to improper operation and personal operating habits during manual winding by workers, thereby improving the assembly consistency and overall service life of the fiber optic gyroscope. Attached Figure Description

[0020] Figure 1 Flowchart of a method for minimizing axial twisting of the fiber optic gyroscope pigtail;

[0021] Figure 2 A simplified diagram of the closed-loop pigtail that has not been coiled after fusion splicing;

[0022] Figure 3 A diagram showing the spatial relationship between a vertically pulled closed-loop pigtail and a smooth cylinder;

[0023] Figure 4A diagram showing the state of the pigtail at the moment the cylinder completes the winding action;

[0024] Figure 5 This is a spatial diagram showing the state of the two pigtail rings after they have been removed from the cylinder following the curing of adhesive. This is in preparation for the next step of rotating the pigtail rings.

[0025] Figure 6 This image shows the action of flipping the pigtail loop and the effect after flipping.

[0026] Figure 7 This is a schematic diagram of the merged pigtail ring.

[0027] In the diagram: 1-Closed-loop pigtail; 2-Optical device; 3-Fiber optic gyroscope; 4-Vertically pulled-up pigtail; 5-Smooth cylinder; 6-Remaining length of vertical pigtail; 7-Intermediate pigtail. Detailed Implementation Plan

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some, not all, of the embodiments of the present invention. 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.

[0029] The features of various aspects of the embodiments of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. The invention is not limited to any specific setups and methods provided below, but covers all improvements, substitutions, etc., to product structures and methods without departing from the spirit of the invention.

[0030] In all the 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.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0033] The present invention provides a method for minimum axial torsion winding of the fiber optic gyroscope pigtail. First, the closed-loop pigtail is vertically pulled up. A smooth cylinder is brought close to the pigtail loop from the side, and a section of the pigtail is attached to the smooth cylindrical surface, remaining relatively stationary. The cylinder is rotated in the direction of rotation of the larger pigtail loop. When the length of the vertical pigtails on both sides is reduced to the required length, the rotation of the cylinder is stopped. Adhesive is applied to the two pigtail loops, and after curing, the pigtails are removed. One side of the fiber loop is flipped, so that the two pigtail loops and the middle section of the pigtail merge into one pigtail loop. This pigtail loop is placed into the cavity. Finally, the remaining pigtails on both sides are wound into the mounting cavity and fixed with adhesive, completing the minimum axial torsion winding of the closed-loop pigtail for the fiber optic gyroscope.

[0034] Please see Figures 2 to 7 The following is a detailed implementation process of the fiber optic gyroscope pigtail winding method of the present invention, the steps of which are as follows:

[0035] Step 1: Lift the pigtail vertically, and approach it from one side with the smooth cylindrical part.

[0036] See the state of the uncoiled closed-loop pigtail after fusion splicing. Figure 2 The pigtail 1 is connected to photoelectric element 2 at both ends, and photoelectric element 2 is installed in fiber optic gyroscope disk 3. For example... Figure 3 As shown, to achieve the method of minimizing axial twisting and coiling of the fiber optic gyroscope pigtail, the middle part of the fused closed-loop pigtail should first be used as the pickup point. The closed-loop pigtail should be vertically lifted, forming pigtail 4 in the figure. Then, a smooth cylinder 5 should be used to approach the pickup point from one side of the pigtail until the vertically pulled pigtail 4 is tangent to the outer cylindrical surface of the smooth cylinder 5. The diameter of the smooth cylinder 5 should be the maximum inscribed circle diameter of the mounting cavity of the fiber optic gyroscope disk 3 minus 1 to 1.5 mm.

[0037] Step 2: Place the upper end of the pigtail against the surface of the cylinder, keeping the contact area in place, and rotate the cylinder.

[0038] Attach the uppermost section of the fiber optic cable to the smooth surface of the cylinder, maintaining its position so that it does not slip relative to the cylinder during rotation. Then rotate the cylinder in the direction of rotation for winding the fiber optic cable. Figure 4 As shown in the diagram, the cylinder should rotate clockwise to wind up the pigtail. As the remaining length of the pigtail decreases, the smooth cylinder 5 moves downward while rotating. It should be noted that the initial length of the middle pigtail 7 attached to the cylinder surface should be half the circumference of the cylinder. This is to ensure that the pigtail ring can be precisely attached to the pigtail ring without any subsequent axial rotation.

[0039] Step 3: When the remaining pigtails reach the required level, stop rotating the cylinder and apply adhesive to the pigtail loops on both sides for curing.

[0040] See Figure 4 As the smooth cylinder 5 continuously winds up the fiber optic cable, the remaining length 6 of the vertical fiber optic cable below the cylinder 5 also decreases. When the remaining length 6 of the vertical fiber optic cable reaches half the circumference of the cylinder, the rotation of the cylinder stops. This length setting ensures that the vertical fiber optic cables on both sides will subsequently merge into a complete loop. Then, the fiber optic cable loops on the left and right sides are glued and cured.

[0041] Step 4: Remove the pigtail, flip one side of the pigtail, and combine the two pigtail loops and the middle connecting pigtail into one pigtail loop.

[0042] Two pigtail loops and a connecting pigtail section in the middle slide out along the same axial direction of the cylinder, such as... Figure 5 Place the two pigtails horizontally along their axis, then flip one of the pigtails to face the other side. Figure 6 As shown, the specific method is as follows: Using the vertical pigtail below the pigtail that needs to be flipped as an axis, rotate 180 degrees towards the other pigtail. After flipping, merge the two pigtails together. The combined effect is as shown. Figure 7 As shown, the specific merging method is as follows: the flipped pigtail ring is moved to place the two pigtail rings coaxially and close together. At this time, the middle pigtail 7, which is exactly half the circumference of the cylinder, is used as a half-loop pigtail ring to connect the left and right pigtail rings. Thus, the two pigtail rings and the middle section of the pigtail ring are merged into one pigtail ring.

[0043] Step 5: Insert the cable into the mounting cavity, and wrap the remaining fiber optic cables on both sides into the mounting cavity, then secure with adhesive.

[0044] The combined pigtail loop is placed into the fiber optic gyroscope mounting cavity. Then, the remaining pigtails on both sides are wound into the mounting cavity in opposite directions. Since the remaining pigtail length 6 set in step 3 is half the circumference of the cylinder, the two remaining pigtails wound into the mounting cavity form a complete pigtail loop. At this point, the pigtail loop inside the mounting cavity has five unbonded parts: two pigtail loops, a half-loop of the middle pigtail, and two half-loops of the remaining vertical pigtail. Therefore, adhesive is applied to fix these five parts together, ensuring the coiled pigtail is securely installed in the fiber optic gyroscope disk and meets the operational requirements of the pigtail.

Claims

1. A method for spooling a fiber optic gyroscope tail fiber with minimal axial twist, comprising: The closed loop tail fiber refers to a closed loop part formed by connecting both ends of the fiber of the fiber optic gyroscope with optical devices. The method of coiling the closed loop tail fiber is as follows: first, the closed loop tail fiber is pulled vertically, a smooth cylinder is approached from the side of the tail fiber coil, a section of the tail fiber is attached to the surface of the smooth cylinder and kept relatively stationary with the cylinder, the cylinder is rotated in the direction of winding the large tail fiber coil, when the lengths of the vertical tail fibers on both sides are reduced to the required length, the rotation of the cylinder is stopped, the two tail fiber rings are glued, and after curing, the tail fiber is taken off, the fiber ring on one side is turned over, so that the two tail fiber rings and the middle section of the tail fiber are combined into one tail fiber ring, the tail fiber ring is placed in the cavity, and finally the remaining tail fibers on both sides are wound into the mounting cavity, glued and fixed, thus completing the minimum axial torsion coiling of the fiber optic gyroscope closed loop tail fiber. ​ 2. The minimum axial torsion coiling method of the fiber optic gyroscope tail fiber according to claim 1, further comprising the following steps: Step 1: taking the middle part of the completed fusion closed loop tail fiber as a pickup point, pulling the closed loop tail fiber vertically, and approaching a smooth cylinder from the side of the tail fiber to the pickup point position; Step 2: attaching a section of the uppermost end of the tail fiber to the surface of the smooth cylinder, keeping its position on the surface of the cylinder, and rotating the cylinder in the direction of winding the tail fiber; Step 3: stopping the rotation of the cylinder when the lengths of the vertical tail fibers below the cylinder reach the required length, gluing the two tail fiber rings at this time so that the tail fiber rings do not spread out after being taken off; Step 4: sliding the two tail fiber rings and the connecting tail fiber in the middle section in the same axial direction of the cylinder, placing the two tail fiber rings horizontally along the axis, turning over the tail fiber ring on one side, so that the connecting tail fiber in the middle is attached to the turned over tail fiber ring, becoming a half-circle tail fiber ring of the same diameter, and combining the left and right tail fiber rings into one tail fiber ring; Step 5: placing the combined tail fiber ring into the gyroscope mounting cavity, and winding the remaining tail fibers on both sides into the cavity, and finally applying a small amount of curing glue to fix all the tail fibers in the mounting cavity.

3. The method of claim 2, wherein the method further comprises: In step 1, the spatial pose of the smooth cylinder is that the axis of the cylinder is horizontal and tangent to the vertical plane of the pulled closed loop tail fiber, and the diameter of the cylinder is the maximum inscribed circle diameter of the gyroscope disc mounting cavity minus 1-1.5 mm.

4. The method of claim 2, wherein the method further comprises: In step 2, the tail fiber is attached to the surface of the cylinder and kept in its position on the surface to limit the degree of freedom of this position, so that the tail fiber below can be wound up, and its length should be half the circumference of the cylinder, which is to ensure that after turning over the tail fiber ring, the tail fiber ring does not need to be rotated axially, and the half-circle long tail fiber can be attached to the tail fiber ring. In step 3, the vertical tail fiber length reaching the required length refers to the lengths of the vertical tail fibers on both sides below the smooth cylinder reaching half the circumference of the cylinder, which is also to ensure that the vertical tail fibers on both sides are combined into a whole circle.

5. The method of claim 2, wherein: In step 4, the turning over of one side of the fiber coil refers to rotating the fiber coil under the vertical fiber by 180 degrees around the vertical fiber as the axis, and the combining of the two fiber coils refers to translating the turned over fiber coil to be coaxial with the other fiber coil and abutting together to become one fiber coil. In step 5, the winding of the remaining fiber into the cavity refers to winding the two remaining fibers in opposite directions to form a fiber coil, and the applying of a small amount of curing glue refers to gluing the two fiber coils, the middle fiber and the remaining vertical fiber.

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