CN210364377U - Unconventional yawing unmanned aerial vehicle - Google Patents

Abstract

The utility model discloses an unconventional driftage unmanned vehicles, its characteristics are: the fixed wing is provided with a trailing edge wing type or a symmetrical wing type, and the thickness of the wing type is changed along the chord direction; one or more fins; a centerline propulsion system with a coaxial counter-rotating motor and propeller forward of the leading edge of the wing; two elevon; and feet or wheels to ensure that the aircraft stands upright. The utility model relates to a model with rotatory wing and fixed wing aircraft advantage combination can carry out the fixed or high skill complex task that the rotatory wing model can't be carried out of various traditions. For example, it can take off and land vertically, which makes it usable almost anywhere. It can also fly quickly and efficiently when converted to its level flight attitude. After reaching the destination, it can be converted to a low-altitude slow-flying posture, accurately moves up, down, left and right in the air, and is suitable for flying indoors due to the small size of the device, so that the device can bypass in urban environment and bypass buildings and obstacles.

Description

Unconventional yawing unmanned aerial vehicle

Technical Field

The invention relates to the field of unmanned aerial vehicles.

Background

Drones have many private and commercial applications as aerial sensor platforms (i.e., video capture), delivery systems, environmental sensing, and communication relays. They may also be used for various purposes related to defense, such as ISR (information monitoring reconnaissance), as a weapons platform, and as an electronic warfare platform. They can be classified by size as micro, mini, tactical (medium), or strategic (large), and methods based on their aerodynamic lift generation can be further classified as: fixed wings, rotating wings, hybrid wings, or flapping wings. According to the us-chinese economic safety and review board report, existing chinese drones lack micro, small, hybrid capability, ornithopter class, and further lack various highly desirable models for private and commercial applications and government functional sector applications such as: search and rescue, border safety, law enforcement, environmental monitoring and defense.

Hybrid drones combine the advantages of both fixed-wing and rotary-wing drones, enabling them to successfully perform tasks that cannot be performed by either fixed-wing or rotary-wing drones alone. The most promising hybrid drone is the vertical take-off and landing (VTOL) fixed wing drone. This kind of unmanned aerial vehicle can fly to remote position fast, high-efficiently like a traditional fixed wing aircraft, then transition to low latitude and fly slowly, hover etc. and unmanned aerial vehicle can fly back to the user fast, high-efficiently once more after the purpose reaches. In essence, the drone performs a mission like a rotary wing model, but from a starting location to a destination like a fixed wing model, greatly improving flight range, endurance, and top speed. The small/miniature version of the hybrid wing drone of the present invention can be placed in a backpack, with the sensor passing through the street and drilling into the building and back, or passing through a mountainous environment that is as good as a few kilometers away along the trail.

Existing hybrid drones use many different designs and configurations. The configuration is a tail-seated vertical take-off and landing airplane and is an unusual airplane type. This is unfortunate in the domestic market as this model is superior to other models in many ways. The machine type of the design is different from VD-200 in China in important essence. First, the two counter-rotating propellers and motors of the VD-200 are both located away from the centerline of the aircraft, adding unnecessary complexity. If one motor fails, the aircraft will crash. However, the two remotely separated motors and propellers contribute to improved rolling inertia roll stability. The components are located within a central fuselage-like compartment in a conventional manner, and are of a hybrid wing-body design. The present invention uses two coaxial propellers located at the centerline of the aircraft, allowing the aircraft to fly safely when one propeller fails. Another advantage of this design is that it counteracts the slipstream generated by the propeller, avoiding the yaw that would otherwise be generated by the slipstream hitting the vertical stabilizer, and thus avoiding the additional air resistance that would otherwise be caused by the yaw rudder compensation. Other components of the present invention are distributed away from the centerline of the vehicle to achieve proper rolling inertia and stability. Other important points and novelty that make the invention unique are: in VD-200, two separate slipstreams and two sets of vertically stable yaw stability (instead of one) are provided, which can control yaw using differential propulsion, while the design of the present invention employs a yaw control single rudder. In addition, VD-200 has ailerons and heave wings that control pitch and roll, respectively. The invention replaces the traditional separate ailerons and liftwings with elevon, thereby simultaneously controlling roll and pitch. The VD-200 has large volume and high cost in design and can only be applied in the military field. The design of the invention can be used by individuals (i.e. expeditioners, enthusiasts, backpackers/pioneers), commercial interests (photography, etc.), and smaller public sector entities (i.e. local enforcement, border safety, environmental monitoring, etc.), with flexible and wide use. It is affordable by a variety of different users, and can be made small enough to be used in a bony mountainous, urban and indoor environment where a larger hybrid powered aircraft cannot fly safely.

The jerky four-rotor fixed wing hybrid model is already in large numbers, a typical example being the HQ-60 model from latitude engineering. Still other similar four-rotor hybrid tail-seating designs are entering the market, including Quantix from aeroversen, and 020 from Swift. These models differ significantly due to the four-rotor hybrid. These models also have high aspect ratio wings. The most similar fixed wing hybrid model tail-seated drone is perhaps still in the development stage of DARPA and is named "gull". This model uses centerline thrust to distinguish from almost all other hover-capable tail-seated fixed-wing aircraft. The gull wing has a high aspect ratio. The main difference is that the gull uses rotor blades (with periodically variable pitch) rather than propeller propellers, enabling it to fly like a helicopter. The design of the rotor blades is complicated and expensive.

The hover-capable fixed-wing model makes its vertical take-off and landing (VTOL) functionality easier to implement. The prior designs use a very small or even zero sweep angle and therefore require the addition of a long rod to the tip to make it a tail-seated model. These long rods are too awkward, heavy, unsightly, and easily break. Many designers therefore omit such long sticks and instead launch them in a hand-held fly or launch with an ejection device and then land on a net or skid.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the unconventional yaw unmanned aerial vehicle overcomes the defects of stall, insufficient maneuverability and stability and low speed of a yaw control system in the prior art, improves the reliability of the yaw control system, and reduces the manufacturing cost and the maintenance cost of the yaw control system.

The invention provides a technical scheme that an unmanned fixed wing aircraft comprises a fixed wing, wherein the fixed wing is provided with a trailing edge wing type or a symmetrical wing type, and the thickness of the wing type is changed along the chord direction; one or more fins; a centerline propulsion system with a coaxial counter-rotating motor and propeller forward of the leading edge of the wing; two elevon; and feet or wheels to ensure that the aircraft stands upright.

Further, at least one fin of the aircraft is located on the plane of symmetry of the aircraft and behind the center of gravity of the aircraft.

Further, the elevon of the aircraft is distributed symmetrically along the plane of symmetry of the aircraft and is substantially the same in size and shape.

Further, the aircraft can vertically take off, vertically land, and/or fly in a hovering state.

Further, the propeller of the aircraft has a fixed and constant pitch angle.

Further, the wing of the aircraft uses a thick airfoil (airfoil thickness > 7% chord length).

Further, the aircraft is provided with a flight wing or an airframe hybrid structure.

Furthermore, the wing of the aircraft has a positive sweep angle relative to a quarter chord line of the wing.

Further, the wing of the aircraft has a low aspect ratio (1-3.5).

Further, the fins of the aircraft that are located on the plane of symmetry of the aircraft do not include a rotatable portion.

Further, the fins of the aircraft, which are positioned on the symmetrical plane of the aircraft, cannot rotate.

Compared with the prior art, the invention has the advantages and positive effects that: the unconventional yaw unmanned aerial vehicle provided by the invention solves the problems of stalling of a yaw control system, insufficient maneuverability and stability and low speed in the prior art. The reliability of yaw control is greatly improved. And the whole system has simple structure and lower manufacturing cost and maintenance cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is an embodiment of the present invention

FIG. 2 shows an aircraft in a conventional flight attitude

FIG. 3 is a bottom view depicting one embodiment of a yaw control system

FIG. 4 is a right side view depicting one embodiment of a yaw control system

FIG. 5 shows an embodiment of a hinge pin

FIG. 6 is an ultra-compact embodiment of the motor saddle

FIG. 7 shows a driving device for elevon

FIG. 8 shows an embodiment of how the servo motor can be embedded in the wing

FIG. 9 shows a dual fin embodiment

FIG. 10 illustrates a multi-fin embodiment

Description of reference numerals: 1. motor saddle, 2 vertical shaft, 3 wing, 4 fin, 5 propeller, 6 lifting aileron, 7 motor, 8 servo motor A, 9 connecting rod A, 10 forward fixing pin hole, 11 hinge pin anchor post, 12 cavity gap, 13 hinge pin, 14 screw thread connecting rod, 15 nut, 16 washer, 17 nylon gasket, 18 carbon fiber tube, 19 wire through hole, 20 wire frame, 21 servo motor B, 22 connecting rod B, 22 lifting aileron hinge pin, 24 support leg, 25 pitot tube, 26 panel, 27 round top, 28 wing airfoil, 29 wheel, 30 radiator, 31 wireless radio frequency window hinge pin

Detailed Description

Fixed wings are used in conventional flight to generate lift to carry the weight of the aircraft. For tail-sitting fixed wing vertical take-off and landing airplanes, the design without a tail wing (also called a flying wing) is very convenient. The flying wing design requires symmetrical or reverse-folded wing profiles to ensure pitch stability. A moderately thick airfoil with a smooth chordwise thickness distribution enables efficient flight while enabling aircraft components to be stored within the wing, which makes the inclusion of a fuselage unnecessary.

One or more fins are placed behind the center of mass of the aircraft to ensure yaw stability. As shown in FIG. 10, the term "fin" herein includes vertical stabilizers, wingtips, winglets and similar devices having a near vertical orientation. The "fins" are typically vertically oriented, but if two or more fins are used, they may be tilted in opposite directions relative to the vertical plane of the aircraft. The fins help to maintain the direction of flight of the aircraft, as does the wind vane pointing into the direction of the wind. Yaw control may be achieved by adding one or more rudders to the fins or by making one or more fins rotatable.

During vertical take-off and landing of the aircraft, as well as during very low speed flight in a hover orientation, the coaxial counter-rotating motor and propeller provide sufficient thrust to carry the weight of the aircraft. Flight in hover is much less efficient than flight in conventional conditions, but is typically only used for short flights. The use of a centerline propulsion system in combination with a centerline fin has a number of advantages. For example, propulsion systems provide a slipstream across the fins, reduce the wind gust sensitivity of the fins (prevent fin stall), and provide yaw control for vertical take-off and hover flight when using rudders and/or full motion fins. When other yaw control methods are used, all fins may be stationary.

Conventional propeller propulsion systems utilizing a single propeller may also provide sufficient thrust, but the present invention does not use this approach. Non-coaxial propeller propulsion systems do not provide slip flow with counter-rotating characteristics, with significant swirl-helical flow. This swirling slipstream, when impinging on one or more of the fins, can result in adverse roll and/or yaw moments. Because such conventional propulsion systems have throttle control, changes in slipstream speed result in unexpected adverse changes in roll and/or yaw moments. Worse still, such conventional propeller propulsion systems result in inertial reaction moments being exerted on the aircraft while throttling (newton's third law). The present invention thus uses a coaxial counter-rotating motor and propeller for counteracting eddy currents and inertial reaction moments to improve the handling characteristics of the aircraft.

Placing the propeller forward of the leading edge of the fixed wing facilitates delaying wing stall and allows one or more fins to be immersed in the propulsive slipstream. The effect of this arrangement is to delay fin stall and enable and improve yaw controllability in hover flight. For low aspect ratio wings, the elevon may be placed near the centerline of the aircraft and thus may also be submerged in the propulsive slipstream. This arrangement provides roll and pitch control in both conventional and hover flight conditions.

The legs enable the vertical take-off and landing aircraft to be upright, commonly referred to as "tail-seating". "foot" means the portion of any structure on an aircraft that contacts the ground to enable the aircraft to stand in a standing, primarily upright orientation (also known as tail sitting) (fig. 1). The wheels may also serve as feet, enabling the larger version of the invention to be easily moved over the ground.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention is capable of many different embodiments, ranging from relatively simple to very complex. A simple embodiment model may not contain any complex features: does not contain special sensors, data storage, or data transmission, but can be supplied to radio control enthusiasts as an interesting and unique model airplane. A complex embodiment may involve complex materials, manufacturing techniques, and internal electronic systems.

Propulsion system

Fig. 1 and 2 depict an embodiment of the present invention. The propulsion force is provided by a coaxial counter-rotating motor. The motor is used to drive the propeller. Electronic speed controllers are used to adjust motor throttle and control propulsion. The coaxial contra-rotating propeller generates slip flow, which generates vortices that are negligibly small.

Wing

The fixed wing of fig. 1 and 2 not only has a sweep angle, but also tapers from the root to the tip, minimizing the energy loss from the tip vortex, which is particularly important for low aspect ratio wings. The specially designed wing airfoil ensures that the aerodynamic forces change gradually (i.e., with a "soft" stall characteristic) as the orientation and control inputs change, and a satisfactory lift coefficient is achieved while maximizing aerodynamic efficiency. The thick wing profile allows the components to be embedded in the wing and the reflexes of the profile add stability to the pitching action. The large area of the wing is immersed in the propulsive slipstream. The aerodynamic characteristics of the wing (including maximum lift coefficient, stall angle of attack, etc.) are strongly dependent on the propeller's approach ratio, as well as many other factors (angle of attack, reynolds number, dimensionless angular speed of rotation, etc.). Developing robust control algorithms to control rapid transitions between conventional flight and hover states, extensive aerodynamic experimentation is necessary.

Fuselage body

The fuselage in this embodiment has a rigid internal frame and a weight-bearing skin to provide maximum strength while minimizing weight. The internal frame also serves as an anchor to secure the diverse internal components. Most structures use carbon fiber, but some parts and surfaces use glass fiber for radio frequency reasons.

Yaw control

In this embodiment, yaw is achieved by thrust induced. As shown in fig. 3-6, the motor saddles are controlled by off-the-shelf radio controlled servo motors and linkages to the wings. At least one fin provides yaw stability during normal flight conditions and supplements yaw control. In other embodiments, yaw control may be achieved through fins and rudders, or through fins that may be described as steerable vertical stabilizers. A hinge pin and hinge pin anchor post secures the motor saddle to the wing. There is a cavity between the skin of the motor saddle and the wing skin so that the motor saddle does not strike the wing when it is undergoing yaw rotation. One of the coaxial counter-rotating motors is mounted inside the motor saddle and the other protrudes outside the motor saddle. The electric wire of the motor is wound outside the internal motor through the wire guide and is connected into the inside of the wing through the wire through hole. A servo motor is built into the motor saddle to drive yaw rotation.

Pitch and rollover control

Fig. 7 and 8 illustrate one embodiment of elevon drive. The elevon can realize pitch and side-turn control. The driving of the elevon is controlled by means of a non-specially designed wireless control servomotor and a link connected to the wing. The push-pull connecting rod protrudes out of the lower surface of the wing, and the purpose of the push-pull connecting rod is to ensure that the airflow on the upper surface of the wing is not damaged. The slipstream covers the elevon and at least one fin and ensures effective aircraft control even at very low speeds of flight and at hover (where the free stream velocity is very small or even zero, but the slipstream is strong). Symmetric deflections of the elevon produce a non-zero pitching moment, while differential deflections of the elevon produce a non-zero rollover moment.

Supporting leg

The foot of the current embodiment of the invention consists of two wingtips, one fin tip and one tip of an additional structure. These tips use rubber pads to facilitate softer landing and better traction. The high sweep angle wing and the fixed fins enable the tail-seated vertical take-off and landing model to be realized without lengthening legs. Two or more fins may also be used as legs, as shown in fig. 9 and 10.

Wireless communication

Unmanned aircraft require wireless communication systems for control. The communication frequency of the embodiment of the invention selects 2.4GHz for GPS, 1240MHz for video transmission and 915MHz for control and remote measurement, so that unmanned aerial vehicle enthusiasts around the world can legally use the embodiment of the invention. While built-in, specially designed and integrally mounted antennas can achieve velocity wave ratios (VSWR) of 1.50 or less. An LC filter reduces interference in a video signal that is transmitted to an OSD Printed Circuit Board (PCB) and then to a video transmitter having a specialized heat sink. To extend the useful service life, servo motors and other electronic components are vibration isolated using foam or rubber materials. Lithium batteries are used to power motors, servomotors and other electronic components.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. An unconventional yaw unmanned aerial vehicle, characterized in that: a fixed wing airfoil (3) having a trailing edge airfoil or symmetrical airfoil (28) with an airfoil thickness that varies chordally; one or more fins (4); a propulsion system located at the centre line of the aircraft, provided with a coaxial counter-rotating motor (7) and a propeller (5) in front of the leading edge of the wing (3); two elevon (6); and feet (24) or wheels (29) to ensure the aircraft stands upright.

2. The aircraft of claim 1, wherein: at least one fin (4) is located on the plane of symmetry of the aircraft and behind the centre of gravity of the aircraft.

3. The aircraft of claim 1, wherein: the elevon (6) is distributed symmetrically along the plane of symmetry of the aircraft and is substantially the same size and shape; the elevon is located at the trailing edge of the wing and in the slipstream of the propeller.

4. The aircraft of claim 1, wherein: the propeller (5) has a fixed and unchangeable pitch angle; the support leg comprises two wingtips and a fin tip.

5. The aircraft of claim 1, wherein: the wing (3) uses thick wing type, the thickness of the wing type is more than 7 percent of chord length; the motor saddle is fixed on the front edge of the wing (3) through a hinge pin and a hinge pin anchor post.

6. The aircraft of claim 1, wherein: having a flying wing or airframe hybrid configuration.

7. The aircraft of claim 1, wherein: the wing (3) has a positive sweep angle relative to a quarter chord line thereof.

8. The aircraft of claim 1, wherein: the wing (3) has a low aspect ratio of 1-3.5.

9. The aircraft of claim 1, wherein: the fins (4) located in the plane of symmetry of the aircraft do not comprise a rotatable part.

10. The aircraft of claim 1, wherein: the fins (4) located in the plane of symmetry of the aircraft cannot rotate.

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