Optical fiber inertial navigation system structure

Abstract

The utility model discloses an optical fiber inertial navigation system structure which comprises a table body and a cover cap, the top face of the table body is open, and a bottom plate of the table body extends towards the periphery to form a base. Inertial sensors are embedded in the outer surface of a first side plate, the outer surface of a second side plate and the lower surface of a base of the table body, a circuit board and a flexible printed board are arranged on the outer surfaces of a third side plate and a fourth side plate respectively, the connecting end of the circuit board faces the fourth side plate, and the first branch end of the flexible printed board is connected with the circuit board; the second branch end of the flexible printed board is bent downwards to be connected with an inertial sensor arranged on the base, and the third branch end of the flexible printed board is bent around the first side plate and the second side plate to be connected with the corresponding inertial sensor; an electronic component is arranged in the table body, meanwhile, the fourth side plate is arranged in a semi-open mode, and the flexible printed board is connected with the electronic component. The cover cap side corresponding to the fourth side plate is provided with an opening, the opening side of the cover cap is provided with a structural panel, the structural panel is provided with an external connector, and the external connector is connected with the flexible printed board.

Description

Technical Field

[0001] The utility model belongs to the technical field of navigation systems, and particularly relates to a fiber optic inertial navigation system structure. Background Art

[0002] Fiber optic inertial navigation system (OFINS) is an advanced navigation technology that uses fiber optic gyroscopes and accelerometers to determine the position and attitude changes of objects. Fiber optic inertial navigation system does not rely on external signals, so it has high autonomy and anti-interference ability. It has been widely used in aerospace, navigation, land transportation and other fields.

[0003] Lightweight and miniaturized fiber-optic inertial navigation systems can be integrated into various new platforms (UAVs, unmanned ships, etc.), which is also beneficial to improve the mobility and flexibility of equipment and reduce energy consumption. Therefore, lightweight and miniaturization have always been an important research direction of fiber-optic inertial navigation systems.

[0004] However, although the fiber optic gyroscope has a very high accuracy, the fiber optic inertial navigation system of the existing technology will cause equipment accuracy drift or inertial device data anomalies after long-term operation (random vibration) due to factors such as angular motion and structural strength, making it difficult to ensure attitude accuracy. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a fiber optic inertial navigation system structure, which can meet the requirements of lightweight and miniaturization while ensuring structural strength, and can effectively ensure attitude accuracy.

[0006] The technical solution of the utility model is achieved in this way:

[0007] The optical fiber inertial navigation system structure comprises a platform body and a cover arranged on the platform body.

[0008] The platform body is a square box structure, the top surface of the platform body is open, the bottom plate of the platform body extends in all directions and is square, thereby forming a base, and mounting holes and cover fixing holes are provided at the four corners of the base, and the cover fixing holes are located on the inner side of the mounting holes; the outer surface of the first side plate of the platform body, the outer surface of the second side plate and the lower surface of the base are all embedded with inertial sensors, and the inertial sensors include optical fiber gyroscopes and accelerometers, the first side plate and the second side plate are adjacently arranged, and the outer surfaces of the third side plate and the fourth side plate are respectively provided with a circuit board and a flexible printed board, the connection end of the circuit board faces the fourth side plate side, the first branch end of the flexible printed board is connected to the circuit board, the second branch end of the flexible printed board is bent downward and connected to the inertial sensor arranged on the base, and the third branch end of the flexible printed board is bent around the first side plate and the second side plate and connected to the corresponding inertial sensor; electronic components are arranged in the platform body, and the connection end of the electronic components faces the fourth side plate side, and the fourth side plate is semi-opened to facilitate the connection of the flexible printed board with the electronic components.

[0009] The cover side corresponding to the fourth side plate is open, and a structural panel is provided on the open side of the cover to close the open side of the cover. An external connector is provided on the structural panel, and the external connector is connected to the flexible printed circuit board.

[0010] Furthermore, the fiber optic gyroscope has an annular structure, and a plurality of connecting ears are evenly distributed on the outer circumference of the fiber optic gyroscope. A first concave cavity is provided on the outer surface of the first side plate, the outer surface of the second side plate and the lower surface of the base. At the same time, a circular concave cavity corresponding to the outer circumference of the fiber optic gyroscope and a connecting step corresponding to the connecting ear are provided in the first concave cavity. The fiber optic gyroscope is embedded in the circular concave cavity, and a connecting hole is provided on the connecting step, so that the fiber optic gyroscope can be fixed on the platform through a connecting piece.

[0011] A sealing plate corresponding to the first concave cavity is provided on the lower surface of the base, so as to close the first concave cavity on the base.

[0012] Furthermore, an accelerometer mounting hole is provided at the center of the circular cavity, so that the accelerometer can be vertically embedded in the accelerometer mounting hole from the outside to the inside, and the accelerometer is connected to the flexible printed circuit board by welding and curing.

[0013] Furthermore, a waveguide mounting seat is provided in the circular cavity on one side of the accelerometer, and the waveguide mounting seat is used to install the waveguide. Both ends of the waveguide mounting seat are arc-shaped structures and correspond to the inner circumference of the fiber optic gyroscope, so as to facilitate the positioning of the fiber optic gyroscope.

[0014] Furthermore, the parallelism between the contact surface of the fiber optic gyroscope and the circular cavity is controlled within 0.012.

[0015] Furthermore, the electronic components include a gyro plate, an IF board and a computer board which are overlapped in sequence from bottom to top, and the connection ends of the gyro plate, the IF board and the computer board are all facing the fourth side plate, so as to facilitate one-to-one connection between the flexible printed circuit board and the connection ends of the gyro plate, the IF board and the computer board.

[0016] Furthermore, the gyro plate, IF plate and computer board are overlapped and arranged on the bracket and fixed to the bracket, a fixing plate corresponding to the bracket is provided in the table body, and the bracket is fixed to the table body, thereby fixing the gyro plate, IF plate and computer board in the table body.

[0017] Furthermore, the structural panel is detachably arranged on the cover.

[0018] Compared with the prior art, the utility model has the following beneficial effects:

[0019] 1. The platform body of the utility model is made of one piece, which can effectively avoid the displacement of the structural components of the platform body due to connection, which is beneficial to improving the vibration resistance of the fiber optic inertial navigation system, thereby ensuring the attitude accuracy; at the same time, the internal connection of the equipment adopts an integrated flexible printed board connection, and all connectors of the flexible printed board are direct-insert printed boards, which are vertically welded on the flexible printed board. In this way, the connectors on the flexible printed board do not need to consider the bending radius during installation, and there is no risk of bending force. It is also beneficial to meet the miniaturization requirements of the equipment, improve the vibration resistance performance, and ensure the attitude accuracy.

[0020] 2. The fiber optic gyroscope of the utility model has an annular structure and is arranged in a circular concave cavity of the table body in a surface-to-surface contact manner, which increases the contact area between the fiber optic gyroscope and the table body, ensures the stable installation of the fiber optic gyroscope, and reduces the risk of angular motion, which is beneficial to ensure the attitude accuracy of the fiber optic inertial navigation system.

[0021] 3. The size of the fiber-optic inertial navigation system of the utility model is less than 20 cm×20 cm×20 cm and weighs less than 2 kg, which meets the requirements of miniaturization and lightweight. In addition, the attitude accuracy of the fiber-optic inertial navigation system does not change by more than 0.03° during vibration. It has good adaptability to anti-vibration environments and has a wide range of application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 -Top view of the internal structure of the fiber-optic inertial navigation system.

[0023] Figure 2-Figure 1 Side view in direction A.

[0024] Figure 3-Figure 1 Side view in direction B.

[0025] Figure 4 - Side view of the platform Figure 1 .

[0026] Figure 5 - Side view of the platform Figure 2 .

[0027] Figure 6 -Front view of the flexible printed circuit board.

[0028] Figure 7 -Top view of the flexible printed circuit board.

[0029] Figure 8 -Schematic diagram of the cover structure.

[0030] Among them: 1-body; 11-base; 12-mounting hole; 13-first side panel; 14-second side panel; 15-third side panel; 16-fourth side panel; 17-waveguide mounting seat; 18-cover fixing hole; 19-accelerometer mounting hole; 110-circular cavity; 111-electronic component accommodating cavity; 2-electronic component; 3-inertial sensor; 31-fiber optic gyroscope; 32-accelerometer; 33-waveguide; 4-circuit board; 5-bracket; 6-flexible printed circuit board; 7-cover; 71-structural panel. DETAILED DESCRIPTION

[0031] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] See also Figure 1 to Figure 8 , Figure 1~Figure 3 The flexible printed circuit board is not included in the structure of the optical fiber inertial navigation system, which includes a platform body 1 and a cover 7 covered on the platform body 1.

[0033] The platform body 1 is integrally formed and has a square box structure. The top surface of the platform body 1 is open, and the bottom plate of the platform body 1 extends in all directions and is square, thereby forming a base 11. Mounting holes 12 and cover fixing holes 18 are provided at the four corners of the base 11, and the cover fixing holes 18 are located inside the mounting holes 12; the outer surface of the first side plate 13 of the platform body 1, the outer surface of the second side plate 14 and the lower surface of the base 11 are all embedded with inertial sensors 3, and the inertial sensors 3 include a fiber optic gyroscope 31 and an accelerometer 32. The first side plate 13 and the second side plate 14 are adjacently arranged, and the outer surfaces of the third side plate 15 and the fourth side plate 16 are respectively A circuit board 4 and a flexible printed board 6 are provided, the connection end of the circuit board 4 faces the fourth side plate 16 side, the first branch end of the flexible printed board 6 is connected to the circuit board 4, the second branch end of the flexible printed board 6 is bent downward and connected to the inertial sensor 3 arranged on the base 11, and the third branch end of the flexible printed board 6 is bent around the first side plate 13 and the second side plate 14 and connected to the corresponding inertial sensor 3; the table body 1 is provided with an electronic component 2, so that an electronic component accommodating cavity 111 is formed in the table body, the connection end of the electronic component 2 faces the fourth side plate side, and the fourth side plate 16 is semi-open, which is convenient for the flexible printed board 6 to be connected to the electronic component 2.

[0034] The cover 7 side corresponding to the fourth side plate 16 is open, and a structural panel 71 is provided on the open side of the cover 7 to close the open side of the cover 7. An external connector is provided on the structural panel 71, and the external connector is connected to the flexible printed circuit board 6.

[0035] The platform here is the installation carrier of the fiber optic inertial navigation system. In order to reduce the weight of the equipment and meet the lightweight requirements, the platform here is made of aluminum material. At the same time, the platform is made of one-piece molding, which can effectively avoid the displacement of the various structural components of the platform due to connection, which is beneficial to improve the vibration resistance of the fiber optic inertial navigation system, thereby ensuring the attitude accuracy.

[0036] At the same time, the open top surface of the platform is conducive to concentrating the center of gravity of the entire equipment on the base, further improving the vibration resistance of the equipment and ensuring posture accuracy.

[0037] The internal wiring of the equipment is connected by an integrated flexible printed circuit board. All connectors on the flexible printed circuit board are direct-insert printed circuit boards and are vertically welded on the flexible printed circuit board. Figure 6 and Figure 7 It can be seen that the flexible printed circuit board is connected to the electronic components and the circuit board accordingly, and one end of the flexible printed circuit board is bent downward and connected to the inertial sensor set on the base, and one end is bent around the first side plate and the second side plate and connected to the inertial sensors on the first side plate and the second side plate. In this way, the connectors on the flexible printed circuit board do not need to consider the bending radius during installation, there is no risk of bending force, and it is conducive to meeting the miniaturization requirements of the equipment, improving the anti-vibration performance, and ensuring the posture accuracy.

[0038] In specific implementation, the fiber optic gyroscope 31 is annular in structure, and a number of connecting ears are evenly distributed on the outer circumference of the fiber optic gyroscope 31. A first concave cavity is provided on the outer surface of the first side plate 13, the outer surface of the second side plate 14 and the lower surface of the base 11. At the same time, a circular concave cavity 110 corresponding to the outer circumference of the fiber optic gyroscope and a connecting step corresponding to the connecting ear are provided in the first concave cavity. The fiber optic gyroscope 31 is embedded in the circular concave cavity, and a connecting hole is provided on the connecting step, so that the fiber optic gyroscope 31 can be fixed to the platform 1 by screws.

[0039] A sealing plate corresponding to the first cavity is provided on the lower surface of the base 11, so as to seal the first cavity on the base 11. The parallelism of the contact surface between the fiber optic gyroscope 31 and the circular cavity 110 is controlled within 0.012.

[0040] In this way, the fiber optic gyroscope and the platform are in surface-to-surface contact, which is conducive to the stable installation of the fiber optic gyroscope, thereby helping to reduce the risk of angular motion. The parallelism between the fiber optic gyroscope and the circular cavity is controlled within 0.012, which is more conducive to improving the attitude accuracy.

[0041] In specific implementation, an accelerometer mounting hole 19 is provided at the center of the circular cavity 110 , so that the accelerometer can be vertically embedded in the accelerometer mounting hole 19 from the outside to the inside, and the accelerometer 32 is connected to the flexible printed circuit board 6 by welding and curing.

[0042] The use of a flexible printed circuit board and the accelerometer pins for welding and curing connection can effectively avoid the risk of the accelerometer cable being easily decoupled due to vibration when welding the cable.

[0043] In a specific implementation, a waveguide mounting seat 17 is provided in the circular cavity 110 on one side of the accelerometer 32. The waveguide mounting seat 17 is used to mount the waveguide 33. Both ends of the waveguide mounting seat 17 are arc-shaped structures corresponding to the inner circumference of the fiber optic gyroscope 31, so as to facilitate the positioning of the fiber optic gyroscope 31. The waveguide mounting seat and the platform are integrally formed.

[0044] This further ensures the installation stability of the fiber optic gyroscope, thereby further ensuring the attitude accuracy.

[0045] In a specific implementation, the electronic component 2 includes a gyro plate, an IF plate, and a computer board which are overlapped in sequence from bottom to top, and the connection ends of the gyro plate, the IF plate, and the computer board are all facing the fourth side plate 16, so that the flexible printed circuit board 6 is connected to the connection ends of the gyro plate, the IF plate, and the computer board in a one-to-one correspondence. Further, the gyro plate, the IF plate, and the computer board are overlapped and arranged on the bracket 5 and fixed to the bracket 5, and a fixing plate corresponding to the bracket 5 is provided in the table body 1, and the bracket 5 is fixed to the table body 1 by screws, so that the gyro plate, the IF plate, and the computer board are fixed in the table body 1.

[0046] In this way, the gyro plate, IF plate and computer board are mounted on the bracket to form an integral component. To reduce weight, the bracket is made of aluminum material, and then the integral component is fastened to the table body, which ensures the tightness of the installation of the electronic components and helps to reduce the risk of resonance of the internal electronic components. The bracket here is a special-shaped structure, which not only supports and fixes the gyro plate, IF plate and computer board, but also fixes the gyro plate, IF plate and computer board to the table body.

[0047] In specific implementation, the structural panel 71 is detachably arranged on the cover 7. The cover is provided with a connection step corresponding to the structural panel, and a fixing hole is provided on the connection step. The edges of the structural panel are provided with through holes corresponding to the fixing holes, so that the structural panel can be fixed to the connection step by screws. At the same time, the structural panel is flush with the corresponding outer surface of the cover. The external connector adopts a solder pin type, which passes through the structural panel and is directly soldered on the flexible printed circuit board, effectively avoiding the solder cup type wiring method and eliminating the risk of disconnection during vibration. The structural panel is detachable and can be replaced according to user needs.

[0048] When designing a fiber-optic inertial navigation system, it is necessary to adjust the center of gravity and geometric center of the equipment so that the deviation distance is within 2mm, perform simulation analysis, adjust the structure, control the resonance point of the console body in the low-frequency area, control the amplification factor within 3 times, and the resonance point of the console body in the high-frequency band must be higher than the highest frequency of random vibration.

[0049] In specific implementation, the wall thickness of each side panel of the platform is smaller than the prisms corresponding to the adjacent two side panels. This can reduce the weight of the platform while strengthening the strength of the four prisms to support the components on the entire platform. At the same time, the intersection area between the four prisms and the base is R-shaped chamfered, which is beneficial to ensure the structural strength of the intersection area.

[0050] The size of the fiber optic inertial navigation system of the utility model is less than 20 cm×20 cm×20 cm and weighs less than 2 kg, which meets the requirements of miniaturization and lightweight. Experimental verification shows that the attitude accuracy of the fiber optic inertial navigation system does not change by more than 0.03° during vibration. It has good adaptability to anti-vibration environments and has a wide range of application prospects.

[0051] Finally, it should be noted that the above embodiments of the present invention are only examples for illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes and modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. The structure of the fiber optic inertial navigation system is characterized by: It comprises a platform body and a cover arranged on the platform body; The platform body is a square box structure, the top surface of the platform body is open, the bottom plate of the platform body extends in all directions and is square, thereby forming a base, and mounting holes and cover fixing holes are provided at the four corners of the base, and the cover fixing holes are located on the inner side of the mounting holes; the outer surface of the first side plate of the platform body, the outer surface of the second side plate and the lower surface of the base are all embedded with inertial sensors, and the inertial sensors include optical fiber gyroscopes and accelerometers, the first side plate and the second side plate are adjacently arranged, and the outer surfaces of the third side plate and the fourth side plate are respectively provided with a circuit board and a flexible printed board, the connection end of the circuit board faces the fourth side plate side, the first branch end of the flexible printed board is connected to the circuit board, the second branch end of the flexible printed board is bent downward and connected to the inertial sensor arranged on the base, and the third branch end of the flexible printed board is bent around the first side plate and the second side plate and connected to the corresponding inertial sensor; electronic components are arranged in the platform body, and the connection end of the electronic components faces the fourth side plate side, and the fourth side plate is semi-opened to facilitate the connection of the flexible printed board with the electronic components; The cover side corresponding to the fourth side plate is open, and a structural panel is provided on the open side of the cover to close the open side of the cover. An external connector is provided on the structural panel, and the external connector is connected to the flexible printed circuit board.

2. The optical fiber inertial navigation system structure according to claim 1, characterized in that: The fiber optic gyroscope is annular in structure, and a plurality of connecting ears are evenly distributed on the outer circumference of the fiber optic gyroscope. A first concave cavity is provided on the outer surface of the first side plate, the outer surface of the second side plate and the lower surface of the base. A circular concave cavity corresponding to the outer circumference of the fiber optic gyroscope and a connecting step corresponding to the connecting ear are provided in the first concave cavity. The fiber optic gyroscope is embedded in the circular concave cavity, and a connecting hole is provided on the connecting step, so that the fiber optic gyroscope can be fixed on the platform through a connecting piece. A sealing plate corresponding to the first concave cavity is provided on the lower surface of the base, so as to close the first concave cavity on the base.

3. The optical fiber inertial navigation system structure according to claim 2, characterized in that: An accelerometer mounting hole is arranged at the center of the circular cavity, so that the accelerometer can be vertically embedded in the accelerometer mounting hole from outside to inside, and the accelerometer is connected to the flexible printed circuit board by welding and curing.

4. The optical fiber inertial navigation system structure according to claim 3, characterized in that: A waveguide mounting seat is provided in the circular cavity on one side of the accelerometer. The waveguide mounting seat is used to install the waveguide. Both ends of the waveguide mounting seat are arc-shaped structures corresponding to the inner circumference of the fiber optic gyroscope, which is convenient for limiting the fiber optic gyroscope.

5. The optical fiber inertial navigation system structure according to claim 2, characterized in that: The parallelism between the contact surface of the fiber optic gyroscope and the circular cavity is controlled within 0.

012.

6. The fiber optic inertial navigation system structure according to claim 1, characterized in that: The electronic components include a gyro plate, an IF plate and a computer board which are overlapped in sequence from bottom to top, and the connection ends of the gyro plate, the IF plate and the computer board are all facing the fourth side plate, so as to facilitate the one-to-one connection between the flexible printed circuit board and the connection ends of the gyro plate, the IF board and the computer board.

7. The optical fiber inertial navigation system structure according to claim 6, characterized in that: The gyro plate, IF plate and computer board are overlapped and arranged on the bracket and fixed to the bracket. A fixing plate corresponding to the bracket is arranged in the table body. The bracket is fixed to the table body, so as to fix the gyro plate, IF plate and computer board in the table body.

8. The optical fiber inertial navigation system structure according to claim 1, characterized in that: The structural panel is detachably arranged on the cover.

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