Intelligent towing cone system for test flight calibration

Abstract

The invention belongs to the technical field of aircraft atmospheric data measurement equipment, and particularly relates to an intelligent towing cone system for test flight calibration, which is used for calibrating flight parameters such as height and speed output by an aircraft atmospheric data system and providing a parameter correction basis. The dragging cone system comprises a static pressure tube, a tail cone body, an optical fiber sensor, a dragging structure and an optical fiber sensing analyzer. According to the invention, the length of the pressure gas circuit of the towed cone system can be shortened, the problem of pressure delay in the existing towed cone product can be solved, the real-time continuous measurement of the pressure of the towed cone system is realized, the dynamic flight calibration of atmospheric parameters is realized, and the test flight calibration efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft atmospheric data measuring equipment, and in particular relates to an intelligent drag cone system for flight test calibration. Background Art

[0002] The aircraft uses the pressure holes on the fuselage or sensors to measure static pressure and calculate altitude. Since the pressure holes are affected by the aerodynamic interference of the fuselage shape, there is an error in the calculated altitude, which needs to be corrected through test flight calibration.

[0003] The drag cone system is an altitude test flight calibration method that is currently recognized both at home and abroad. It uses a long rope to drag the static pressure tube to the interference area of ​​the tail of the aircraft away from the airflow to measure a clean static pressure signal; the tail increases resistance through the tail cone to reduce the swing of the static pressure tube.

[0004] The existing drag cone system senses pressure through a static pressure tube. The long nylon tube directly transmits pressure. The length of the nylon tube is about 100m, which brings a very large pressure delay to the pressure measurement. As a result, the static pressure measurement of the calibration drag cone system and the static pressure system being calibrated on the aircraft are not synchronized. The delay can only be avoided by flying at a fixed altitude and flying at the same altitude for a long time. The calibration test flight is inefficient and the test flight altitude state is discontinuous.

[0005] Because longer nylon tubes often have problems such as micro-leakage during pressure transmission, the measurement accuracy of the flight test calibration is affected, resulting in invalid flight test calibration flights. Summary of the invention

[0006] In view of this, the present invention provides an intelligent drag cone system for test flight calibration, in which a static pressure tube is arranged at the tail of the aircraft, a new micro optical fiber pressure sensor is built into the static pressure tube, static pressure is directly collected, and the pressure signal is transmitted to the aircraft through an optical fiber line; thus, a long nylon tube is omitted for pressure gas path transmission. The present invention can shorten the transmission length of the pressure gas path of the drag cone system, solve the pressure delay problem and the transmission pipeline leakage problem in the test flight calibration, realize the real-time continuous measurement of the pressure of the drag cone system, and improve the test flight calibration efficiency.

[0007] The technical solution of the present invention is:

[0008] An intelligent drag cone system for flight test calibration is used to calibrate flight parameters such as altitude and speed of aircraft air data system data. The drag cone system includes:

[0009] The towing structure has three layers: a nylon tube, a Kevlar fiber rope, and an optical fiber line; the Kevlar fiber rope is located in the center, with one end connected to the tail of the aircraft and the other end connected to the static pressure tube and the tail cone to withstand the aerodynamic force during use; one end of the internal optical fiber signal line is connected to the optical fiber sensor and the other end is connected to the optical fiber sensor analyzer inside the aircraft, and is designed and fixed to the Kevlar fiber rope with an anti-wear design to achieve output signal transmission of the optical fiber sensor; the external nylon tube is connected to the static pressure tube and the tail cone to play a conformal role, conform to the static pressure tube, and smoothly transition to ensure high-precision acquisition of the static pressure tube and reduce aerodynamic errors;

[0010] The static pressure tube is connected to the tail of the aircraft at one end through a dragging structure; and is connected to the tail cone at the other end through a dragging structure. During use, the static pressure tube is straightened by the aerodynamic force of the tail cone, away from the influence of the tail flow field of the aircraft, to achieve high-precision measurement of static pressure; multiple pressure measuring holes are opened around the static pressure tube to achieve static pressure sensing;

[0011] The optical fiber pressure sensor adopts a microstructure design and is built into the static pressure tube to collect the air pressure signal collected by the static pressure tube, connect with the optical fiber line in the drag structure, and transmit the pressure signal to the optical fiber sensor analyzer through the optical fiber line;

[0012] The tail cone is located at the very end of the drag cone system and is connected to the static pressure tube through a drag structure. Its specially designed aerodynamic shape and internal connection mechanism enable it to rotate under the action of aerodynamic force, driving the static pressure tube to a straight state;

[0013] The fiber optic sensor analyzer is located inside the cabin. It receives the model of the fiber optic pressure sensor, realizes the conversion and calculation of the fiber optic pressure signal, calculates the pressure signal into a digital signal, and transmits it to the aircraft.

[0014] Furthermore, the optical fiber pressure sensor adopts an ingenious micro-internal structure design built into a 10mm diameter static pressure tube, including two optical fiber FP pressure sensitive chips and a temperature compensation sensor; it achieves rapid response to pressure changes, reduces pressure delay, and meets dynamic flight calibration requirements. The micro optical fiber pressure sensor and the static pressure tube are fixed by a threaded and sealant combination structure.

[0015] Furthermore, the fiber optic sensing analyzer is installed inside the cabin and used in conjunction with a miniature fiber optic pressure sensor to perform fiber optic pressure acquisition calculations and temperature compensation calculations, thereby achieving high-precision, high-response acquisition of static pressure signals in a high-altitude flight environment.

[0016] Furthermore, the optical fiber line supporting the micro optical fiber pressure sensor adopts an anti-wear design to avoid signal failure caused by line wear during long-distance transmission.

[0017] Furthermore, the internal connecting rope of the dragging structure adopts a high-strength Kevlar fiber rope, which is light in weight, high in strength and low in cost; it is light and soft, and can reduce the wear on the optical fiber line. The Kevlar fiber rope and the optical fiber line are fixed in sections to avoid internal entanglement, knotting and wear.

[0018] Furthermore, a connection ear is cleverly designed at one end of the static pressure tube, so as to realize the reliable connection and fixation of the Kevlar fiber rope and the safe transmission of the optical fiber line.

[0019] Furthermore, the distance between the static pressure tube and the tail of the aircraft is 1 to 2 times the wingspan of the aircraft; 3 rows of 8 pressure measuring holes with an aperture of 0.8-1.2mm and evenly distributed at 45° are arranged around the static pressure tube to achieve high-precision perception of static pressure under different angles of attack and sideslip angles.

[0020] Furthermore, the tail cone adopts a hollow cone structure, is made of low-density reinforced glass fiber, and has a plurality of guide circular holes on the main body; an axial load-bearing bearing is arranged inside the tail cone structure, and during use, under the traction of the airflow through the guide circular holes, the tail cone rotates around the static pressure tube through the bearing, thereby forming a good aerodynamic traction force and effectively straightening the static pressure tube.

[0021] Beneficial effects of the present invention:

[0022] The present invention connects the static pressure tube and the tail cone at the tail of the aircraft through a dragging structure; the aerodynamic force of the tail cone straightens the static pressure tube and drags it to the tail of the aircraft; the static pressure tube senses the high-precision static pressure signal far away from the aircraft, and the high-precision optical fiber pressure sensor built in the vicinity of the static pressure tube collects the static pressure signal, transmits it to the optical fiber sensor analyzer inside the aircraft through the optical fiber transmission line, and calculates the static pressure signal and transmits it to the aircraft; the dragging structure plays the role of conforming to the static pressure tube, bearing the drag force, and transmitting the optical fiber line; in order to drag the static pressure tube to the wake influence area far away from the aircraft, the length of the dragging structure may reach about 100m. The present invention sets a static pressure tube at the tail of the aircraft, builds a new micro optical fiber pressure sensor into the static pressure tube, directly collects the static pressure, and transmits the pressure signal to the aircraft through the optical fiber line; thus, a long nylon tube is omitted for pressure gas path transmission. The present invention can shorten the transmission length of the pressure gas path of the drag cone system, solve the pressure delay problem and the transmission pipeline leakage problem in the test flight calibration, realize the real-time continuous measurement of the pressure of the drag cone system, and improve the test flight calibration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the static pressure pipe structure;

[0025] Figure 2 It is a schematic diagram of the sensor structure;

[0026] Figure 3 Schematic diagram of aerodynamic characteristics of tail cone;

[0027] Figure 4 It is a schematic diagram of the layout of the pressure sensor;

[0028] Figure 5 It is a structural diagram of the intelligent cone dragging system;

[0029] Figure 6 It is a schematic diagram of the connection between the dragging structure and the static pressure pipe;

[0030] Figure 7 Schematic diagram of the tail vertebrae structure;

[0031] Among them: 1. static pressure tube; 2. pressure sensor; 3. tail cone; 31. bearing; 4. drag structure; 41. nylon tube; 42. Kevlar fiber rope; 43. optical fiber line. DETAILED DESCRIPTION

[0032] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0033] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0034] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0035] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The illustrations only show components related to the present disclosure rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0036] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0037] In one embodiment of the present invention, an intelligent drag cone system for flight test calibration is provided, which is used to calibrate the altitude, speed and other parameters output by the aircraft air data system. Figure 1-Figure 4 , the drag cone system comprises:

[0038] The dragging structure 4 has three layers: a nylon tube 41, a Kevlar fiber rope 42, and an optical fiber line 43; the Kevlar fiber rope 42 is located in the center, one end of which is connected to the tail of the aircraft, and the other end is connected to the static pressure tube 1 and the tail cone 3, so as to withstand the aerodynamic force during use; one end of the internal optical fiber signal line is connected to the optical fiber sensor, and the other end is connected to the optical fiber sensor analyzer inside the aircraft, and is designed to be wear-resistant and fixed to the Kevlar fiber rope 42 to realize the output signal transmission of the optical fiber sensor; the external nylon tube 41 is connected to the static pressure tube 1 and the tail cone 3, plays a conformal role, conforms to the static pressure tube 1, and has a smooth transition, so as to ensure the high-precision acquisition of the static pressure tube 1 and reduce aerodynamic errors;

[0039] The static pressure pipe 1 has one end connected to the tail of the aircraft through the drag structure 4; the other end is connected to the tail cone 3 through the drag structure 4; during use, the static pressure pipe 1 is straightened by the aerodynamic force of the tail cone 3, away from the influence of the tail flow field of the aircraft, so as to achieve high-precision measurement of static pressure; multiple pressure measuring holes are set around the static pressure pipe 1 to achieve static pressure sensing;

[0040] The optical fiber pressure sensor 2 adopts a microstructure design and is built into the static pressure tube 1 to collect the air pressure signal collected by the static pressure tube 1, and is connected to the optical fiber line 43 in the drag structure 4 to transmit the pressure signal to the optical fiber sensor analyzer through the optical fiber line 43;

[0041] The tail cone 3 is located at the end of the drag cone system and is connected to the static pressure pipe 1 through the drag structure 4. Its specially designed aerodynamic shape and internal connection mechanism enable it to rotate under the action of aerodynamic force, driving the static pressure pipe 1 to be in a straight state;

[0042] The optical fiber sensing analyzer is located inside the cabin, receives the model of the optical fiber pressure sensor 2, realizes the conversion and calculation of the optical fiber pressure signal, calculates the pressure signal into a digital signal, and transmits it to the aircraft.

[0043] In this embodiment, the optical fiber pressure sensor 2 adopts an ingenious micro-internal structure design built into a static pressure tube 1 with a diameter of 10mm, including two optical fiber FP pressure sensitive chips (3*3*2.3mm) and a temperature compensation sensor (0.85*10mm); it realizes rapid response to pressure changes, reduces pressure delay, and meets dynamic flight calibration requirements. The structural parts are sealed by laser welding, and the top is connected and sealed by an M6 external thread interface. The material is 316L stainless steel. The maximum outer diameter of the overall structure is 8mm and the length is 45.2mm; the micro optical fiber pressure sensor 2 and the static pressure tube 1 are fixed by a combination of threads and sealants.

[0044] In this embodiment, the fiber optic sensor analyzer is installed inside the cabin and is used in conjunction with the micro fiber optic pressure sensor 2 to perform fiber optic pressure acquisition calculations and temperature compensation calculations, thereby achieving high-precision and high-response acquisition of static pressure signals in a high-altitude flight environment.

[0045] In this embodiment, the optical fiber line 43 of the micro optical fiber pressure sensor 2 adopts an anti-wear design to avoid signal failure caused by line wear during long-distance transmission.

[0046] In this embodiment, the internal connecting rope of the dragging structure 4 is a high-strength Kevlar fiber rope 42, which is light in weight, high in strength and low in cost; it is light and soft, and can reduce the wear of the optical fiber line 43. The Kevlar fiber rope 42 and the optical fiber line 43 are fixed in sections to avoid internal entanglement, knotting and wear.

[0047] In this embodiment, a connection ear is cleverly designed at one end of the static pressure tube 1 to achieve reliable connection and fixation of the Kevlar fiber rope 42 and safe transmission of the optical fiber line 43.

[0048] In this embodiment, the distance between the static pressure tube 1 and the tail of the aircraft is 1 to 2 times the wingspan of the aircraft; 3 rows of 8 pressure measuring holes with an aperture of 0.8-1.2 mm and uniformly distributed at 45° are arranged around the static pressure tube 1 to achieve high-precision perception of static pressure under different angles of attack and sideslip angles.

[0049] In this embodiment, the tail cone 3 adopts a hollow cone structure, made of low-density reinforced glass fiber, and a plurality of guide holes are arranged on the body; an axial bearing bearing 31 is arranged inside the tail cone 3 structure, and under the traction of the airflow of the guide hole during use, the tail cone 3 rotates around the static pressure tube 1 through the bearing 31, forming a good aerodynamic traction force, and effectively straightening the static pressure tube 1. The tail cone 3 adopts low-density reinforced glass fiber material, with a wall thickness of 3mm-5mm, and is lightweight and high-strength to achieve a balance between tension and resistance. The axial bearing bearing 31 uses a thrust ball bearing 31 that can withstand an axial force of 5kN; the connection method between the inner ring of the bearing 31 and the wire rope is a connecting shaft connection; the outside of the pressure pipeline is fastened by a special air circuit clamp; the air circuit clamp and the air circuit adapter nozzle are connected and fixed based on a fuse; the pipeline sealing part and the threaded connection part are sealed and prevented from loosening by glue coating.

[0050] In this embodiment, the nylon tube 41 is made of nylon material with good flexibility, elasticity and resistance to low temperature of -55°C, and is bent and suitable for sealing and retracting mechanisms.

[0051] In this embodiment, the Kevlar fiber rope 42 has a diameter of 2.5 mm / 2.15 mm and can withstand a tensile force of up to 5 kN.

[0052] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. An intelligent drag cone system for test flight calibration, used to calibrate the altitude and speed flight parameters output by the aircraft air data system, characterized in that: The drag cone system comprises: The towing structure includes three layers: a nylon tube, a Kevlar fiber rope and an optical fiber line; the Kevlar fiber rope is located in the center, one end of which is connected to the tail of the aircraft, and the other end is connected to the static pressure tube and the tail cone, so as to withstand the aerodynamic force during use; one end of the optical fiber line is connected to the optical fiber sensor, and the other end is connected to the optical fiber sensor analyzer inside the aircraft, and is designed to be wear-resistant and fixed to the Kevlar fiber rope to achieve output signal transmission of the optical fiber sensor; the nylon tube covered with the Kevlar fiber rope is connected to the static pressure tube and the tail cone, and conforms to the static pressure tube and smoothly transitions; The static pressure tube has one end connected to the tail of the aircraft through a dragging structure, and the other end connected to the tail cone through a dragging structure; the aerodynamic static pressure tube passing through the tail cone is in a straightened state during use, away from the influence of the tail flow field of the aircraft, and is used to measure the static pressure at the location; a plurality of pressure measuring holes are provided around the static pressure tube to realize static pressure sensing; The optical fiber pressure sensor adopts a microstructure design and is built into the static pressure tube to collect the air pressure signal collected by the static pressure tube, and is connected to the optical fiber line to transmit the pressure signal to the optical fiber sensor analyzer through the optical fiber line; The tail cone is located at the end of the drag cone system and is connected to the static pressure tube through a drag structure. Based on the aerodynamic shape and internal bearings, it rotates under the action of aerodynamic force and drives the static pressure tube to a straight state; The optical fiber sensing analyzer is located inside the cabin, receives the signal of the optical fiber pressure sensor, realizes the conversion and calculation of the optical fiber pressure signal, calculates the pressure signal into a digital signal and transmits it to the aircraft.

2. The intelligent drag cone system for flight test calibration according to claim 1, characterized in that: The optical fiber pressure sensor is built into a static pressure tube with a diameter of 10 mm, and includes two optical fiber FP pressure sensitive chips and a temperature compensation sensor; the micro optical fiber pressure sensor and the static pressure tube are fixed together by a thread and a sealant.

3. The intelligent drag cone system for flight test calibration according to claim 2, characterized in that: A fiber optic sensing analyzer is installed inside the cabin of the aircraft and is used in conjunction with the fiber optic pressure sensor to perform fiber optic pressure acquisition calculations and temperature compensation calculations to achieve acquisition of static pressure signals in a high-altitude flight environment.

4. The intelligent drag cone system for flight test calibration according to claim 3, characterized in that: The optical fiber line that comes with the miniature optical fiber pressure sensor adopts an anti-wear design.

5. The intelligent drag cone system for flight test calibration according to claim 4, characterized in that: The Kevlar fiber rope and the optical fiber line are fixed in sections.

6. The intelligent drag cone system for flight test calibration according to claim 5, characterized in that: A connection ear is provided at one end of the static pressure tube for achieving reliable connection and fixation with the Kevlar fiber rope and safe transmission of the optical fiber line.

7. The intelligent drag cone system for flight test calibration according to claim 6, characterized in that: The distance between the static pressure tube and the tail of the aircraft is 1 to 2 times the wingspan of the aircraft; 3 rows of 8 pressure measuring holes with an aperture of 0.8-1.2mm and uniformly distributed at 45° are arranged around the static pressure tube to achieve static pressure sensing under different attack angles and sideslip angles.

8. The intelligent drag cone system for flight test calibration according to claim 7, characterized in that: The tail cone adopts a hollow cone structure, is made of low-density reinforced glass fiber, and is provided with a plurality of guide circular holes on the main body; an axial load-bearing bearing is provided inside the tail cone, and during use, under the traction of the airflow through the guide circular holes, the tail cone rotates around the static pressure tube through the bearing, forming a pneumatic traction force to straighten the static pressure tube.

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