A method for improving the fiber laying uniformity of the fiber optic ring in a fiber optic gyroscope

Abstract

The present invention discloses a method for improving the fiber laying uniformity in an optical fiber gyroscope, which comprises the following steps: 1) obtaining a mathematical model of the winding tension T of the optical fiber ring and the interlayer fiber spacing L1: L1 = 0.8738T<supgt;2< / supgt> - 12.699T + 66.018; 2) arranging a spiral groove at the bottom of the groove of the optical fiber winding ring tooling; 3) taking the spacing L2 as the in-layer fiber spacing, and calculating the required winding tension according to the mathematical model in step 2); 4) winding the optical fiber in a quadrupole symmetry manner, using the tension value calculated in step 3) as the winding tension value, and curing the surface of the optical fiber ring after winding; 5) performing heating and rotation treatment on the cured optical fiber ring, and finally completing the winding of the optical fiber ring. The present invention improves the spacing consistency of the optical fiber in all directions within the optical fiber ring, and can significantly improve the laying uniformity of the optical fiber in the optical fiber ring.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber optic gyroscopes, and particularly to a method for improving the fiber laying uniformity in a fiber optic gyroscope. Background Art

[0002] A fiber optic gyroscope is an inertial instrument for measuring angular velocity, with the characteristic of high autonomy, and can be used in inertial navigation systems. Due to its all-solid-state structure, wide dynamic range, short startup time, and strong anti-shock ability, it has been widely used in modern aviation, aerospace, and defense industries and other fields.

[0003] The key component in a fiber optic gyroscope is the fiber optic coil, which is the optical path core for sensing angular velocity. To solve the influence of the fiber optic coil on temperature and stress changes, a four-pole symmetric winding method is usually adopted during the winding of the fiber optic coil. In this way, the fibers at equal distances from the midpoint are in adjacent positions, so as to have nearly equal temperatures, temperature gradients, and stresses. The four-pole symmetry includes stress symmetry and position symmetry, and the position symmetry is closely related to the fiber laying uniformity. The degree of four-pole symmetry determines the amplitude of the influence of the fiber optic coil on temperature and stress changes, which makes the symmetry of the fiber optic coil an important technical requirement in high-precision fiber optic gyroscopes. Since the fiber optic coil needs to maintain the all-solid-state characteristic, usually an adhesive is used to bond the arranged fibers into a whole, which results in that the fiber arrangement is not completely in close contact, but a certain amount of adhesive is filled, causing a spacing between the turns of the fiber optic coil after winding, and the sizes of the spacings are different, greatly affecting the symmetry of the fiber optic coil, as Figure 1 shown.

[0004] In order to improve the fiber laying uniformity, various means are adopted during the winding process of the fiber optic coil, such as image recognition, using cushion layer compensation, non-adhesive winding, etc. However, there are still problems of poor uniformity of the fiber arrangement spacing between layers and within layers of the fiber optic coil, and the inconsistency between the inter-layer fiber spacing and the intra-layer fiber spacing. These problems of non-uniform fiber laying have a very obvious impact on the accuracy of high-precision fiber optic gyroscopes. Especially for the outer fibers far from the midpoint, the proportion of the position asymmetry caused by the inconsistent fiber spacing significantly increases, seriously affecting the accuracy of high-precision fiber optic gyroscopes.

[0005] Therefore, it is necessary to establish a method for improving the fiber laying uniformity in a high-precision fiber optic gyroscope through technical research. Summary of the Invention

[0006] Aiming at the above-mentioned deficiencies existing in the prior art, the purpose of the present invention is to solve the problem of poor fiber arrangement uniformity during the winding process of the fiber optic coil, and provide a method for improving the fiber laying uniformity in a fiber optic gyroscope.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for improving the fiber laying uniformity of the fiber optic ring in a fiber optic gyroscope, characterized by comprising the following steps:

[0008] 1) Wind the fiber optic ring under different winding tensions T. After winding is completed, for each wound fiber optic ring, measure the interlayer fiber spacing L1 on the cross-section of the fiber optic ring to obtain the mathematical model of the fiber optic ring winding tension T and the interlayer fiber spacing L1:

[0009] L1 = 0.8738T 2 - 12.699T + 66.018;

[0010] Wherein: L1 is the interlayer fiber spacing; T is the fiber optic ring winding tension;

[0011] 2) Set a spiral groove with a circular arc cross-section at the bottom of the groove of the fiber optic ring winding tool. The spiral groove extends along the axial direction of the winding tool and is wound around the bottom of the groove of the winding tool. The spacing between adjacent turns of the spiral groove is L, where L < L1;

[0012] 3) Take the spacing L2 as the in-layer fiber spacing and make L2 = L1. According to the mathematical model in step 2), calculate the required winding tension;

[0013] 4) Wind the optical fiber in a quadrupole symmetric manner. Among them, the winding tension value adopts the tension value calculated in step 3). After winding is completed, cure the surface of the fiber optic ring;

[0014] 5) Heat and rotate the cured fiber optic ring to finally complete the winding of the fiber optic ring.

[0015] Further, in step 1), according to the quadrupole symmetric winding method, in the tension range with a minimum value of 4 g and a maximum value of 7.5 g, with a tension increment of 0.5 g, wind fiber optic rings with a winding length of 600 meters under different tensions. After curing is completed, cut open the fiber optic ring, use an optical microscope to measure the average value L1 of the interlayer fiber spacing on the cross-section of the fiber optic ring, and finally fit the mathematical model according to the relationship between the winding tension and the interlayer fiber spacing.

[0016] Further, in step 4), during the curing process, the rotation speed is 30 rpm and the rotation angle is 1080 degrees.

[0017] Further, in step 5), the heating temperature is not lower than 50 °C, the rotation speed is 5 rpm, and the processing time is not less than 12 h.

[0018] Compared with the prior art, the present invention has the following advantages: It solves the problems of lack of control means for the in-layer fiber arrangement during the production process of fiber optic rings and the large difference between the in-layer fiber arrangement spacing and the inter-layer fiber arrangement spacing, improves the consistency of the spacing of the fibers in all directions within the fiber optic ring, and can significantly improve the uniformity of the fiber arrangement in the fiber optic ring. Description of the Drawings

[0019] Figure 1 It is a fiber distribution diagram of the prior fiber winding process.

[0020] Figure 2 It is a mathematical model diagram of the winding tension and the inter-layer fiber spacing.

[0021] Figure 3 It is a fiber distribution diagram of the fiber winding process in the present invention.

[0022] In the figure: 1 - optical fiber, 2 - winding tooling for the ring. Detailed Embodiments

[0023] The present invention will be further described below in conjunction with the drawings and embodiments.

[0024] Embodiment: Refer to Figure 2 、 Figure 3 , a method for improving the fiber arrangement uniformity in a fiber optic gyroscope, including the following steps:

[0025] 1) Wind the fiber optic ring under different winding tensions T. After winding is completed, for each wound fiber optic ring, measure the inter-layer fiber spacing L1 on the cross-section of the fiber optic ring to obtain the mathematical model of the fiber optic ring winding tension T and the inter-layer fiber spacing L1:

[0026] L1 = 0.8738T 2 - 12.699T + 66.018;

[0027] Wherein: L1 is the inter-layer fiber spacing; T is the fiber optic ring winding tension.

[0028] The method for obtaining the above mathematical model is as follows:

[0029] According to the four-pole symmetric winding method, in the tension range with a minimum value of 4 g and a maximum value of 7.5 g, with a tension increment of 0.5 g, where g represents grams. Since the tension magnitude is measured by the weight of the weights, the unit is g, which means the weight of the weights hanging on the tension wheel. Wind fiber optic rings with a length of 600 meters under different tensions. After curing is completed, cut open the fiber optic rings and use an optical microscope to measure the average value L1 of the inter-layer fiber spacing on the cross-section of the fiber optic rings. Finally, fit the mathematical model according to the relationship between the winding tension and the inter-layer fiber spacing.

[0030] During the implementation process, the relationship between the specifically obtained tension T and the interlayer optical fiber spacing L1 is as follows in the table:

[0031]

[0032] 2) A spiral groove with a circular-arc cross-section is provided at the bottom of the groove of the optical fiber winding ring tooling 2. The spiral groove extends along the axial direction of the winding ring tooling 2 and is wound around the bottom of the groove of the winding ring tooling 2. The spacing between adjacent turns of the spiral groove is L, where L < L1. After using the winding tooling with a spiral groove at the bottom of the groove, the spacing between the in-layer optical fibers of the bottom layer optical fiber is strictly constrained, ensuring the uniformity of the fiber laying of the bottom layer optical fiber, so as to ensure that the optical fibers stacked above it can also be neatly arranged.

[0033] 3) Taking the spacing L2 as the in-layer optical fiber spacing and making L2 = L1, according to the mathematical model in step 2), the required winding tension is calculated.

[0034] 4) The optical fiber 1 is wound in a quadrupole symmetry manner. Among them, the winding tension value adopts the tension value calculated in step 3). After winding is completed, the surface of the optical fiber ring is cured; during the curing process, a device with a power of 20 mW / cm 2 —40 mW / cm 2 drives the optical fiber ring to rotate, so that the rotation speed of the optical fiber ring is 30 rpm and the rotation angle is 1080 degrees. Such a curing method can cure the adhesive on the surface of the optical fiber ring, while the adhesive inside the optical fiber ring remains in a liquid state and has good fluidity.

[0035] 5) The cured optical fiber ring is heated and rotated, and finally the winding of the optical fiber ring is completed. Among them, the heating temperature is not lower than 50 °C, the rotation speed is 5 rpm, and the treatment time is not less than 12 h. Thus, stress relaxation is performed on the non-uniformly arranged optical fibers caused by abnormal factors such as winding tension fluctuations and uneven adhesives in 4), so that the optical fibers are naturally stretched to achieve a uniform arrangement effect.

[0036] Since adhesives are coated during the optical fiber winding process, there are gaps between the optical fibers. This solution solves the problems of lack of control means for in-layer optical fiber arrangement and large difference between the in-layer optical fiber arrangement spacing and the interlayer optical fiber arrangement spacing during the optical fiber winding process. By controlling the tension and compressing the adhesive, the spacing consistency in all directions of the optical fibers in the optical fiber ring is improved, and the uniformity of the optical fiber arrangement in the optical fiber ring can be significantly improved.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those of ordinary skill in the art should understand that any modifications or equivalent replacements made to the technical solutions of the present invention without departing from the purpose and scope of the present technical solution should be covered by the scope of the claims of the present invention.

Claims

1. A method for improving the fiber laying uniformity of the fiber optic loop in a fiber optic gyroscope, characterized in that: The steps are as follows: 1) Wind the fiber optic ring under different winding tensions T. After winding is completed, for each wound fiber optic ring, measure the interlayer fiber spacing L1 at the cross-section of the fiber optic ring to obtain a mathematical model of the winding tension T of the fiber optic ring and the interlayer fiber spacing L1: L1 = 0.8738T 2 -12.699T + 66.018; where: L1 is the interlayer fiber spacing; T is the winding tension of the fiber optic ring; Among them, according to the four-pole symmetric winding method, in the tension range with a minimum value of 4 g and a maximum value of 7.5 g, with a tension increment of 0.5 g, wind fiber optic rings with a winding length of 600 m at different tensions. After curing is completed, cut open the fiber optic ring and use an optical microscope to measure the average value of the interlayer fiber spacing L1 on the cross-section of the fiber optic ring. Finally, fit the mathematical model according to the relationship between the winding tension and the average value of the interlayer fiber spacing L1; 2) Set a spiral groove with a circular-arc cross-section at the bottom of the groove of the fiber optic ring winding tooling. The spiral groove extends along the axial direction of the winding tooling and is wound around the bottom of the groove of the winding tooling. The spacing between adjacent turns of the spiral groove is L, where L < L1; 3) Use the spacing L2 as the in-layer fiber spacing and make L2 = L1. According to the mathematical model in step 2), calculate the required winding tension; 4) Wind the optical fiber in a four-pole symmetric manner. Among them, the winding tension value uses the tension value calculated in step 3). After winding is completed, cure the surface of the fiber optic ring; during the curing process, the rotation speed is 30 rpm and the rotation angle is 1080 degrees; 5) Perform heating and rotation treatment on the cured fiber optic ring to finally complete the winding of the fiber optic ring; among them, the heating temperature is not lower than 50 °C, the rotation speed is 5 rpm, and the treatment time is not less than 12 h.

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