Aircraft stall sensing unit and aircraft stall sensing system

Abstract

An aircraft stall sensing unit and an aircraft stall sensing system. The aircraft stall sensing unit (10) comprises a housing (100), a rotating unit (200), a friction power generation unit (300), and a limiting assembly (400); the rotating unit can rotate relative to the housing in the return airflow direction of the surface of a wing (20) of an aircraft; and the limiting assembly is used for limiting the rotation of the rotating unit in the laminar airflow direction of the surface of the wing of the aircraft. The friction power generation unit comprises independent friction layers (310), electrode pairs (320) and dielectric friction groups (330), and when the rotating unit rotates relative to the housing in the return airflow direction of the surface of the wing, the independent friction layers rotate relative to the dielectric friction groups and rub to generate an electric signal. The aircraft stall sensing unit is used for determining whether the aircraft is stalled.

Description

Aircraft stall sensing unit and aircraft stall sensing system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on November 23, 2023, with application number 202311579200.2 and application name “Aircraft Stall Sensing Unit and Aircraft Stall Sensing System”, the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the technical field of aircraft stall detection, and in particular to an aircraft stall sensing unit and an aircraft stall sensing system. Background Art

[0004] Stall is caused by the sudden decrease in lift provided by the wing when the aircraft's angle of attack exceeds the stall angle. At this time, the air adhering to the wing surface decreases, and the boundary layer separates from the wing surface prematurely, making the wing unable to provide sufficient lift. The lift and gravity are no longer balanced, causing the aircraft to fall.

[0005] For small UAVs, stall detection devices currently used in large manned aircraft, such as angle of attack sensors, Mach sensors, and flap position sensors, are precise and reliable, but are unsuitable for small UAVs due to their large size, weight, and complex structure. Furthermore, existing stall sensors require an additional power supply. For small UAVs powered solely by batteries, this additional power module increases the pressure on power management and hinders the lightweight design of small UAVs.

[0006] Summary of the Invention

[0007] The present disclosure provides an aircraft stall sensing unit and an aircraft stall sensing system, which are not only suitable for determining whether a small unmanned aerial vehicle has entered a stall state, but also do not require an additional power module, which is conducive to achieving a lightweight design of the small unmanned aerial vehicle.

[0008] In a first aspect, the present disclosure provides an aircraft stall sensing unit, mounted on an aircraft wing, the aircraft stall sensing unit comprising a housing, a rotating unit, a friction power generation unit, and a limit assembly, wherein the rotating unit, the friction power generation unit, and the limit assembly are disposed within the housing, and the housing has an opening for communicating between the interior and exterior of the housing;

[0009] The rotating unit can rotate relative to the housing along the direction of the return airflow on the wing surface of the aircraft;

[0010] The rotating unit is connected to the housing via the limiting assembly, and the limiting assembly is used to limit the rotation of the rotating unit relative to the housing along the direction of the laminar airflow on the wing surface of the aircraft;

[0011] The triboelectric power generation unit includes an independent friction layer, an electrode pair, and a dielectric friction group, wherein the electrode pair includes a first electrode and a second electrode arranged at intervals, and the dielectric friction layer includes a first dielectric friction layer and a second dielectric friction layer arranged at intervals, wherein the first dielectric friction layer is located between the first electrode and the independent friction layer, and the second dielectric friction layer is located between the second electrode and the independent friction layer;

[0012] The independent friction layer is fixed to the rotating unit, and the electrode pair and the dielectric friction group are fixed to the shell. When the rotating unit rotates relative to the shell along the direction of the return airflow on the wing surface, the independent friction layer rotates relative to the dielectric friction group and generates an electrical signal through friction.

[0013] The aircraft stall sensing unit disclosed herein is configured to detect whether an aircraft is stalled by providing a rotating unit, a triboelectric unit, and a limiter assembly. The aircraft stall sensing unit is mounted on the wing surface. When the aircraft is in flight, external airflow can enter the housing through an opening in the housing. If the aircraft is in level flight, the airflow entering the housing is in the direction of laminar flow along the wing surface. In this case, the rotating unit cannot rotate relative to the housing due to the limiting action of the limiter assembly, and the triboelectric unit does not generate an electrical signal. If the aircraft is in a stalled state, the airflow entering the housing is in the direction of backflow. In this case, the rotating unit can rotate relative to the housing, and the triboelectric unit generates an electrical signal. Therefore, the aircraft stall sensing unit disclosed herein can determine whether the aircraft is stalled by detecting whether the triboelectric unit generates an electrical signal. Its simple structure facilitates miniaturization. Furthermore, because the triboelectric unit can generate its own electricity, no additional power module is required, which also facilitates the lightweight design of small unmanned aerial vehicles.

[0014] In some possible implementations, the housing includes a bottom shell and an upper cover, the bottom shell and the upper cover are detachably connected, and the opening is provided on the upper cover;

[0015] The rotating unit is located in the bottom shell, and the electrode pair and the dielectric friction group are fixedly connected to the upper cover.

[0016] In some possible implementation schemes, the rotating unit includes a rotating shaft, a connecting member, and a plurality of fan blades;

[0017] One end of the rotating shaft is connected to the bottom of the bottom shell, and the other end of the rotating shaft is connected to the connecting member, and the axis direction of the rotating shaft is perpendicular to the laminar airflow direction of the wing surface of the aircraft;

[0018] A plurality of blades are arranged on the surface of the connecting member around the circumference of the connecting member, one end of the blade is connected to the connecting member, and the other end of the blade is bent toward the connecting member along the direction of the laminar airflow on the wing surface.

[0019] In some possible implementation schemes, an included angle is formed between the fan blade and the axis of the rotating shaft, and the included angle is 15° to 75°.

[0020] In some possible embodiments, the limiting assembly includes a ratchet and pawl mechanism;

[0021] A groove is provided on one side of the connecting member facing the upper cover, the ratchet is fixed in the middle of the groove, and the top end of the ratchet protrudes from the groove;

[0022] The pawl mechanism is fixed to the upper cover. When the upper cover is closed on the bottom shell, the ratchet wheel abuts against the pawl mechanism. The pawl mechanism is used to limit the ratchet wheel from rotating in the direction of the laminar airflow on the wing surface of the aircraft.

[0023] In some possible embodiments, the independent friction layer is fixed to the inner wall of the groove, the electrode pair and the dielectric friction group are located on the side of the upper cover facing the bottom shell, and when the upper cover is closed on the bottom shell, the electrode pair and the dielectric friction layer are located in the groove.

[0024] In some possible implementation schemes, the rotating shaft is connected to the bottom shell through a bearing.

[0025] In some possible implementations, there are two independent friction layers, two electrode pairs, and two dielectric friction groups, respectively. The two independent friction layers are symmetrically arranged and spaced apart. The two electrode pairs and the two dielectric friction groups are respectively arranged corresponding to the two independent friction layers.

[0026] The two first electrodes of the two electrode pairs are connected via a first copper wire, and the two second electrodes of the two electrode pairs are connected via a second copper wire.

[0027] In some possible implementations, the two first electrodes are symmetrically arranged, and the two second electrodes are symmetrically arranged.

[0028] In a second aspect, the present disclosure provides an aircraft stall sensing system, comprising an aircraft and a plurality of aircraft stall sensing units as described in any possible embodiment of the first aspect;

[0029] A plurality of the aircraft stall sensing units are arranged along the chord direction of the wing and installed on the wing surface of the aircraft, and one of the aircraft stall sensing units is close to the tail of the wing. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative work.

[0031] FIG1a is a schematic diagram of the airflow state of the wing surface of the aircraft in level flight;

[0032] FIG1b is a schematic diagram of the airflow state of the wing surface when the aircraft is in a stall state;

[0033] FIG2 is a schematic diagram of an exploded structure of an aircraft stall sensing unit according to an embodiment of the present disclosure;

[0034] FIG3 is a schematic structural diagram of a friction power generation unit in an embodiment of the present disclosure;

[0035] FIG4 is a schematic diagram of the structure of an aircraft stall sensing unit installed on a wing surface in an embodiment of the present disclosure;

[0036] FIG5 is a schematic diagram of signal output of an aircraft stall sensing unit according to an embodiment of the present disclosure.

[0037] Figure markings: 10-aircraft stall sensing unit; 20-wing; 100-housing; 110-bottom shell; 111-stopper; 120-upper cover; 121-opening; 122-accommodating hole; 200-rotating unit; 210-rotating shaft; 220-connecting piece; 221-groove; 230-blade; 300-friction power generation unit; 310-independent friction layer; 320-electrode pair; 321-first electrode; 322-second electrode; 330-dielectric friction group; 331-first dielectric friction layer; 331a-friction section; 331b-connecting section; 332-second dielectric friction layer; 340-first copper wire; 350-second copper wire; 400-limiting assembly; 410-ratchet; 411-ratchet; 420-pawl mechanism; 421-limiting surface; 500-bearing. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0039] Referring to Figures 1a and 1b, Figure 1a illustrates the airflow over the wing surface of an aircraft in level flight, while Figure 1b illustrates the airflow over the wing surface of an aircraft in stall. As shown in Figure 1a, in level flight, the laminar airflow over the wing surface adheres to the upper surface of the wing due to the Coanda effect. As shown in Figure 1b, when the aircraft's angle of attack is too large, airflow separation occurs over the wing surface. In this state, a backflow (as indicated by the airflow number 2 in Figure 1b) occurs at the tail of the wing, with the direction of the backflow opposite to the laminar airflow.

[0040] 2 , the aircraft stall sensing unit 10 in the disclosed embodiment includes a housing 100, a rotating unit 200, a triboelectric power generation unit 300, and a stop assembly 400. The housing 100 has a storage space within which the rotating unit 200, the triboelectric power generation unit 300, and the stop assembly 400 are disposed. The housing 100 may include a bottom shell 110 and an upper cover 120, which may be attached to the bottom shell 110. For example, the bottom shell 110 and the upper cover 120 are detachably connected, allowing the upper cover 120 to be removed later for repair or replacement of components within the housing 100, such as the rotating unit 200 and the triboelectric power generation unit 300.

[0041] Continuing with reference to FIG2 , the rotating unit 200 includes a rotating shaft 210, a connecting member 220, and a plurality of blades 230. One end of the rotating shaft 210 is connected to the bottom of the bottom shell 110, and the other end is connected to the connecting member 220. The axial direction of the rotating shaft 210 can be regarded as perpendicular to the laminar airflow direction of the wing aerofoil of the aircraft. The connecting member 220 is a cylindrical structure, and the plurality of blades 230 are connected to the surface of the connecting member 220 around the circumference of the connecting member 220. The rotating shaft 210 can rotate relative to the housing 100 around its own axis to drive the blades 230 to rotate relative to the housing 100 around the axis of the rotating shaft 210. That is, the rotating unit 200 as a whole can rotate along the laminar airflow direction (X direction) or the return airflow direction (Y direction) of the wing aerofoil of the aircraft.

[0042] Furthermore, as shown in Figure 2, the rotation unit 200 is connected to the upper cover 120 via a limiting assembly 400. Specifically, the limiting assembly 400 includes a ratchet 410 and a pawl mechanism 420. The ratchet 410 is fixedly connected to the rotation unit 200, and the pawl mechanism 420 is fixedly connected to the upper cover 120. A groove 221 is provided on the side of the connecting member 220 facing the upper cover 120. The ratchet 410 can be fixedly connected to the middle of the groove 221, and the axis of the ratchet 410 can coincide with the axis of the rotating shaft 210. The ratchet 410 includes a plurality of circumferentially arranged ratchet teeth 411. Each ratchet tooth 411 is bendable toward the central axis of the ratchet 410, in the direction of the laminar airflow on the aircraft's wing surface. Furthermore, the pawl mechanism 420 includes a limiting surface 421. One of the ratchet teeth 411 of the ratchet 410 abuts against the limiting surface 421, thereby limiting rotation of the ratchet 410 relative to the pawl mechanism 420 in the direction of the laminar airflow on the aircraft's wing surface. Since the ratchet 410 is fixedly connected to the rotation unit 200 and the pawl mechanism 420 is fixedly connected to the upper cover 120, the abutment between the ratchet 410 and the pawl mechanism 420 can be used to limit rotation of the rotation unit 200 relative to the housing 100.

[0043] In addition, the surface of the pawl mechanism 420 facing the ratchet 410 is an arcuate surface, and the pawl mechanism 420 is curved toward the central axis of the ratchet 410 along the direction of the return airflow of the aircraft's wing surface. In other words, the pawl mechanism 420 and the ratchet teeth 411 extend in opposite directions. When the ratchet 410 rotates relative to the pawl mechanism 420 along the direction of the return airflow of the aircraft's wing surface, the pawl mechanism 420 does not restrict the ratchet 410. In other words, under the action of the limit assembly 400, the rotating unit 200 in this embodiment cannot rotate along the laminar airflow direction (X direction) of the aircraft's wing surface, but can rotate along the direction of the return airflow (Y direction) of the aircraft's wing surface.

[0044] Referring to Figures 2 and 3 , the triboelectric power generation unit 300 includes an independent friction layer 310, an electrode pair 320, and a dielectric friction group 330. The independent friction layer 310 is fixed to the rotating unit 200, while the electrode pair 320 and dielectric friction group 330 are fixed to the side of the upper cover 120 facing the bottom housing 110. Specifically, the electrode pair 320 may include a first electrode 321 and a second electrode 322, with the first electrode 321 and the second electrode 322 spaced apart. The dielectric friction group 330 may include a first dielectric friction layer 331 and a second dielectric friction layer 332, with the first dielectric friction layer 331 and the second dielectric friction layer 332 spaced apart. The first dielectric friction layer 331 may be fixedly connected to the first electrode 321 and located between the first electrode 321 and the independent friction layer 310. Similarly, the second dielectric friction layer 332 may be fixedly connected to the second electrode 322 , and the second dielectric friction layer 332 is located between the second electrode 322 and the independent friction layer 310 .

[0045] As previously mentioned, the ratchet 410 is located in the center of the groove 221, maintaining a certain distance between the ratchet 410 and the sidewalls of the groove 221. The independent friction layer 310 is fixedly attached to the inner wall of the groove 221. When the upper cover 120 is closed on the bottom shell 110, the electrode pair 320 and the dielectric friction group 330 can also extend into the space between the ratchet 410 and the inner wall of the groove 221, and the dielectric friction group 330 and the independent friction group are in contact. When the rotating unit 200 rotates relative to the housing 100, the independent friction layer 310 slides against the dielectric friction group 330, thereby generating an electrical signal.

[0046] Continuing with reference to Figure 2, the upper cover 120 is provided with an opening 121, which can be used to connect the interior of the housing 100 with the exterior. When the aircraft stall sensing unit 10 in this embodiment is mounted on the wing surface of the aircraft, external airflow can enter the interior of the housing 100. When the aircraft is in level flight, the direction of the airflow inside the housing 100 is the same as the direction of the laminar airflow on the wing surface. At this time, the blades 230 tend to rotate in the direction of the laminar airflow on the wing surface. However, due to the restraining action of the ratchet 410 and the pawl mechanism 420, the blades 230 remain relatively fixed to the housing 100, and the triboelectric power generation unit 300 does not generate an electrical signal. When the aircraft is in a stall state, the direction of the airflow inside the housing 100 is the same as the direction of the return airflow on the wing surface. At this time, the blades 230 rotate relative to the housing 100 in the direction of the return airflow on the wing surface, and the triboelectric power generation unit 300 generates an electrical signal.

[0047] It should be understood that the aircraft stall sensing unit 10 of this embodiment utilizes the rotation unit 200, the stop assembly 400, and the triboelectric power generation unit 300. By acquiring the electrical signal generated by the triboelectric power generation unit 300 when the aircraft is in a stalled state, it can quickly determine whether the aircraft is in a stalled state. Furthermore, because the triboelectric power generation unit 300 can generate its own electricity, the aircraft stall sensing unit 10 serves as both a stall sensor and a power source, eliminating the need for additional electrical modules on the aircraft and facilitating a lightweight design for the aircraft.

[0048] Continuing to refer to Figure 2, the rotating shaft 210 can be connected to the bottom of the bottom shell 110 through a bearing 500, which can also reduce the friction between the fan blades 230 and the base when rotating, thereby making the electrical signal changes generated by the fan blades 230 when rotating more sensitive, thereby improving the accuracy of detection.

[0049] Furthermore, one end of each fan blade 230 is fixedly connected to the connector 220, and the other end can be bent toward the ratchet 410 along the direction of the laminar airflow on the aircraft's wing surface. In this way, when the external return airflow enters the housing 100, it can be more convenient to drive the fan blade 230 to rotate. In addition, a certain angle can be set between each fan blade 230 and the axial direction of the rotating shaft 210. This angle can be between 15° and 75° to increase the contact area between the fan blade 230 and the return airflow. In this way, the fan blade 230 can be driven to rotate under the action of a smaller return airflow, thereby more quickly determining that the aircraft is in a stall state, thereby improving the accuracy of detection.

[0050] As shown in Figure 3, there can be two independent friction layers 310. The two independent friction layers 310 can be symmetrically spaced and arranged circumferentially around the inner wall of the connector 220. Correspondingly, there are also two pairs of electrode pairs 320 and two pairs of dielectric friction groups 330. That is, there are two first electrodes 321, two second electrodes 322, two first dielectric friction layers 331, and two second dielectric friction layers 332. One first electrode 321, one first dielectric friction layer 331, one second electrode 322, one second dielectric friction layer 332, and one independent friction layer 310 form a triboelectric generation structure. The two first electrodes 321 are connected by a first copper wire 340, and the two second electrodes 322 are connected by a second copper wire 350. In this embodiment, the two triboelectric generation structures form the triboelectric generation unit 300. The electrical signals generated by the two triboelectric generation structures are superimposed to increase the number of electrical signals and more sensitively reflect changes in the electrical signals, thereby facilitating the determination of whether the aircraft is stalled.

[0051] It is worth noting that the number of independent friction layers 310 in this embodiment is not limited to one or two. In other embodiments, the number of independent friction layers 310 may also be three, four, etc. Correspondingly, the number of electrode pairs 320 and dielectric friction groups 330 is the same as the number of independent friction layers 310. It should be understood that, given limited space, increasing the number of independent friction layers 310 can increase the number of electrical signals and thus the current, thereby making it easier to intuitively determine the stall state of the aircraft through the electrical signals.

[0052] Continuing with FIG3 , taking one set of first electrodes 321 and first dielectric friction layer 331 as an example, the first dielectric friction layer 331 includes a friction segment 331a for sliding frictional contact with the independent friction layer 310 and a connecting segment 331b that bends toward and extends between the two independent friction layers 310. The first dielectric friction layer 331 can be connected to the upper cover 120 via the connecting segment 331b. Thus, by bending a portion of the first dielectric friction layer 331 toward the center, the first dielectric friction layer 331 is effectively secured to the upper cover 120 while maintaining sufficient contact area between the first dielectric friction layer 331 and the independent friction layer 310, thereby generating more electrical signals.

[0053] Similarly, a portion of the second dielectric friction layer 332 is also bent toward the center to ensure that the second dielectric friction layer 332 is not only effectively fixed to the upper cover 120, but also has a sufficient contact area with the independent friction layer 310. In this embodiment, the length of each first electrode 321 is the same as the length of the first dielectric friction layer 331, and the length of the second electrode 322 is the same as the length of the second dielectric friction layer 332. In other words, a portion of the first electrode 321 and the second electrode 322 are also bent toward the center, which facilitates the connection between the two first electrodes 321 and the connection between the two second electrodes 322.

[0054] Furthermore, the two first electrodes 321 can be symmetrically arranged about the axis of the ratchet 410, and the two second electrodes 322 can be symmetrically arranged about the axis of the ratchet 410, so that the electrodes do not interfere with each other. Furthermore, the first electrodes 321 and the second electrodes 322 are staggered. When the fan blades 230 rotate, no matter how much the fan blades 230 rotate, each independent friction layer 310 can maintain sliding friction with a first dielectric friction layer 331 and a second dielectric friction layer 332.

[0055] 2 and 3 , a space is defined between the two first electrodes 321 and the second electrode 322 for passing the ratchet 410. A receiving hole 122 is also defined in the middle of the upper cover 120 for receiving the ratchet 410. The ratchet mechanism 420 can be disposed on the inner wall of the receiving hole 122. The ratchet 410 protrudes from the groove 221. When the upper cover 120 is closed onto the bottom housing 110, a portion of the ratchet 410 is located within the receiving hole 122 and abuts against the ratchet mechanism 420.

[0056] In addition, the side wall of the bottom shell 110 can also be provided with a circumferentially arranged stop portion 111. When the upper cover 120 is covered with the bottom shell 110, the side of the upper cover 120 facing the bottom shell 110 abuts against the stop portion 111, and the outer surface of the upper cover 120 abuts against the inner wall of the bottom shell 110, thereby ensuring the stability of the connection between the upper cover 120 and the bottom shell 110.

[0057] In this embodiment, multiple blades 230 are evenly distributed along the circumference of connector 220. The number of blades 230 is not limited. For example, as shown in FIG2 , there can be eight blades 230. It should be understood that, given a given area of ​​blades 230, increasing the number of blades 230 can increase the contact area between the blades 230 and the return airflow. Furthermore, the minimum diameter of the circle enclosed by each blade 230 at one end away from connector 220 is 30 mm to ensure sufficient contact area between the blades 230 and the return airflow.

[0058] The height of each ratchet tooth 411 of the ratchet wheel 410 is 6mm to 10mm, and the diameter of the tooth top circle is 11mm to 18mm, so as to ensure that the ratchet tooth 411 has sufficient contact area with the pawl mechanism 420, and ensure that the ratchet tooth 411 cannot rotate relative to the pawl mechanism 420 when the aircraft is in level flight.

[0059] The outer diameter of the housing 100 is 46 mm to 70 mm, the sidewall thickness of the bottom shell 110 is 7 mm to 10 mm, the height of the sidewall of the bottom shell 110 is 4 mm to 7 mm, the thickness of the upper cover 120 is 2 mm to 5 mm, and the thickness of the bottom of the bottom shell 110 is 1 mm to 2 mm. Thus, through the above-mentioned dimensional design, the overall size of the aircraft stall sensor unit 10 can be minimized, thereby facilitating a miniaturized design. When the aircraft stall sensor unit 10 is installed on a small unmanned aerial vehicle, it will not significantly affect the weight of the aircraft.

[0060] Furthermore, the material of the independent friction layer 310 can be polyamide, with a width of 2mm to 6mm, a length of 10mm to 20mm, and a thickness of 10μm to 100μm. The material of the first dielectric friction layer 331 and the second dielectric friction layer 332 can be a fluorinated ethylene propylene copolymer material, with a width of 2mm to 6mm, a length of 10mm to 20mm, and a thickness of 10μm to 100μm. The material of the first electrode 321 and the second electrode 322 can be a metallic conductive material such as copper, with a width of 2mm to 6mm, a length of 10mm to 20mm, and a thickness of 10μm to 100μm. The first electrode 321 can be attached to the first dielectric friction layer 331 using the adhesive backing of the fluorinated ethylene propylene copolymer material, and the second electrode 322 can be attached to the second dielectric friction layer 332 using the adhesive backing of the fluorinated ethylene propylene copolymer material.

[0061] The material of the shell 100 and the fan blades 230 can be one of polymer materials such as polylactic acid, photosensitive resin, aviation plastics and metal, so as to ensure that the shell 100 and the fan blades 230 will not be damaged by airflow during the flight of the aircraft.

[0062] Based on the same inventive concept, embodiments of the present disclosure may also provide an aircraft stall sensing system. Referring to FIG4 , this system may include an aircraft and an aircraft stall sensing unit 10 as described in the embodiments of the present disclosure. The aircraft includes a wing 20, and a plurality of aircraft stall sensing units 10 are mounted on the surface of the wing 20, with one aircraft stall sensing unit 10 located near the tail of the wing 20. Furthermore, the plurality of aircraft stall sensing units 10 are arranged along the chord direction of the wing 20.

[0063] 5 , the aircraft stall sensing unit 10 further includes a control unit. The control unit is signal-connected to each aircraft stall sensing unit 10 for receiving the electrical signal generated by each aircraft stall sensing unit 10. By processing the electrical signal and further analyzing the aircraft's flight status, the state of airflow separation on the aircraft surface can be determined to achieve the purpose of stall monitoring.

[0064] For example, when a mild stall occurs, the blades 230 of the stall sensing unit 10 located at the tail of the wing 20 begin to rotate, while the blades 230 of the stall sensing unit 10 located farther from the tail do not rotate, indicating that airflow separation is still limited to the tail portion of the wing 20. As the aircraft's angle of attack continues to increase, the blades 230 of the stall sensing unit 10 located farther away begin to rotate. Thus, by providing multiple stall sensing units 10, the turning point position can be roughly monitored, achieving the purpose of stall degree detection. Furthermore, when the aircraft stalls due to excessive angle of attack caused by environmental influences or improper operator operation, a warning can be issued to the operator, alerting them to the specific stall state, such as mild stall or deep stall, and guiding them to take appropriate action as soon as possible to ensure flight safety.

[0065] The above description is merely an illustrative embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. An aircraft stall sensor unit, mounted on an aircraft wing surface, characterized in that: The aircraft stall sensing unit comprises a housing, a rotating unit, a friction power generation unit and a limit assembly, wherein the rotating unit, the friction power generation unit and the limit assembly are arranged inside the housing, and the housing is provided with an opening for connecting the inside and the outside of the housing; The rotating unit can rotate relative to the housing along the direction of the return airflow on the wing surface of the aircraft; The rotating unit is connected to the housing through the limiting assembly, and the limiting assembly is used to limit the rotation of the rotating unit relative to the housing along the laminar airflow direction of the wing surface of the aircraft; The friction power generation unit includes an independent friction layer, an electrode pair and a dielectric friction group, the electrode pair includes a first electrode and a second electrode arranged at intervals, the dielectric friction layer includes a first dielectric friction layer and a second dielectric friction layer arranged at intervals, the first dielectric friction layer is located between the first electrode and the independent friction layer, and the second dielectric friction layer is located between the second electrode and the independent friction layer; The independent friction layer is fixed to the rotating unit, the electrode pair and the dielectric friction group are fixed to the shell, and when the rotating unit rotates relative to the shell along the direction of the return airflow on the wing surface, the independent friction layer rotates relative to the dielectric friction group and generates an electrical signal through friction.

2. The aircraft stall sensing unit according to claim 1, characterized in that: The housing comprises a bottom shell and an upper cover, the bottom shell and the upper cover are detachably connected, and the opening is arranged on the upper cover; The rotating unit is located in the bottom shell, and the electrode pair and the dielectric friction group are fixedly connected to the upper cover.

3. The aircraft stall sensing unit according to claim 2, characterized in that: The rotating unit includes a rotating shaft, a connecting member and a plurality of fan blades; One end of the rotating shaft is connected to the bottom of the bottom shell, and the other end of the rotating shaft is connected to the connecting member, and the axis direction of the rotating shaft is perpendicular to the laminar airflow direction of the wing surface of the aircraft; A plurality of blades are arranged on the surface of the connecting member around the circumference of the connecting member, one end of the blade is connected to the connecting member, and the other end of the blade is bent toward the connecting member along the direction of the laminar airflow on the wing surface.

4. The aircraft stall sensing unit according to claim 3, characterized in that: An included angle is formed between the fan blade and the axis of the rotating shaft, and the included angle is 15° to 75°.

5. The aircraft stall sensing unit according to claim 3, characterized in that: The limiting assembly includes a ratchet and pawl mechanism; A groove is provided on one side of the connecting member facing the upper cover, the ratchet is fixed in the middle of the groove, and the top end of the ratchet protrudes from the groove; The pawl mechanism is fixed to the upper cover. When the upper cover is covered on the bottom shell, the ratchet wheel abuts against the pawl mechanism. The pawl mechanism is used to limit the rotation of the ratchet wheel along the laminar airflow direction of the wing surface of the aircraft.

6. The aircraft stall sensing unit according to claim 5, characterized in that: The independent friction layer is fixed to the inner wall of the groove, the electrode pair and the dielectric friction group are located on the side of the upper cover facing the bottom shell, and when the upper cover is closed on the bottom shell, the electrode pair and the dielectric friction layer are located in the groove.

7. The aircraft stall sensing unit according to claim 3, characterized in that: The rotating shaft is connected to the bottom shell through a bearing.

8. The aircraft stall sensing unit according to claim 1, characterized in that: There are two independent friction layers, two electrode pairs and two dielectric friction groups respectively, the two independent friction layers are symmetrically arranged and spaced apart, and the two electrode pairs and the two dielectric friction groups are respectively arranged corresponding to the two independent friction layers; The two first electrodes of the two electrode pairs are connected via a first copper wire, and the two second electrodes of the two electrode pairs are connected via a second copper wire.

9. The aircraft stall sensing unit according to claim 8, characterized in that: The two first electrodes are symmetrically arranged, and the two second electrodes are symmetrically arranged.

10. An aircraft stall sensing system, characterized in that: comprising an aircraft and a plurality of aircraft stall sensing units according to any one of claims 1 to 9; A plurality of the aircraft stall sensor units are arranged along the chord direction of the wing and installed on the wing surface of the aircraft, and one of the aircraft stall sensor units is close to the tail of the wing.

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