Ducted unmanned aerial vehicle noise reduction device based on bent micro-perforated plate acoustic liner

Abstract

The ducted unmanned aerial vehicle noise reduction device is characterized in that the ducted unmanned aerial vehicle noise reduction device comprises a ducted noise reduction structure and a supporting structure, the ducted noise reduction structure comprises an outer duct and an inner duct, the outer duct comprises an outer duct back plate, an outer duct cavity and an outer duct bent micro-perforated plate acoustic liner, and the supporting structure comprises an inner duct back plate and an outer duct bent micro-perforated plate acoustic liner. The inner duct comprises an inner duct back plate, an inner duct cavity and an inner duct bent micro-perforated plate acoustic liner, and the inner duct is placed in the outer duct and connected with the outer duct through a supporting structure. The supporting structure comprises a supporting strip and a supporting seat, the supporting strip is connected with the bottom of the outer duct, and the supporting seat is located at the central axis of the outer duct and connected with the inner duct. Due to the fact that the outer duct and the inner duct form a noise reduction structure based on the bent micro-perforated plate acoustic liner, most of motor noise and noise generated during rotation of the propeller can be effectively absorbed, and the noise reduction function is achieved. On the premise that the weight and the size are not increased too much, the purpose of reducing the noise of the propellers and the motors of the ducted unmanned aerial vehicle is achieved, and good application value is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and in particular to a ducted unmanned aerial vehicle noise reduction device based on a curved micro-perforated plate sound lining. Background Art

[0002] With the development of UAV technology, ducted UAVs have been widely used in logistics distribution, aerial photography and monitoring and other fields due to their unique aerodynamic layout and flight characteristics. However, the noise problem generated by ducted UAVs during flight has also received increasing attention. The main sources of ducted UAVs are motors and propellers, among which broadband noise and eddy current noise caused by high-speed rotation of propellers dominate. These noises not only interfere with the surrounding environment, but may also affect the mission execution of the UAV. In order to reduce the noise of ducted UAVs and improve their applicability in sensitive environments, it is particularly important to develop effective noise reduction technology. In order to reduce the noise of ducted UAVs, researchers have carried out a lot of research work.

[0003] The Chinese patent application number is 201820920056.2, which discloses a drone duct structure with noise reduction function. The drone is provided with a sound-absorbing layer and a sound-insulating layer to absorb the noise generated when the motor drives the propeller to rotate, and a hydrophobic heat dissipation layer is provided on the outermost side to prevent external water from entering the casing to destroy the internal sound-absorbing structure, and at the same time, the heat generated by the noise vibration absorbed by the sound-absorbing layer is dissipated.

[0004] The Chinese patent application number is 202210695068.0, which discloses a ducted UAV noise reduction device based on blade tip acoustic metamaterials. Its mechanism is to generate secondary noise by setting a maze-type noise reduction unit on the inner wall of the duct, and to cancel each other out because the amplitude of the secondary noise at the blade frequency or its harmonic frequency is close to the amplitude of the blade frequency or its harmonic noise of the UAV body and the phase is close to anti-phase, thereby reducing the blade frequency or its harmonic noise of the UAV body.

[0005] Although a variety of noise reduction technologies have been proposed, these technologies often have problems such as complex structure, high cost or affect the performance of UAVs. Therefore, a ducted UAV noise reduction device based on curved micro-perforated plate acoustic lining is proposed to achieve the purpose of reducing the propeller and motor noise of ducted UAVs without increasing too much weight and volume. Summary of the invention

[0006] The technical problem to be solved by the present invention is: to propose a ducted UAV noise reduction device based on a curved micro-perforated plate sound lining, so as to achieve the purpose of reducing the noise of the ducted UAV without increasing too much weight and volume.

[0007] The objective of the present invention is achieved through the following technical solution: A ducted UAV noise reduction device based on a curved micro-perforated plate sound lining, comprising: a ducted noise reduction structure and a supporting structure.

[0008] The duct noise reduction structure includes an outer duct and an inner duct. The outer duct includes an outer duct backplate, an outer duct cavity and an outer duct curved micro-perforated plate sound lining. The inner duct includes an inner duct backplate, an inner duct cavity and an inner duct curved micro-perforated plate sound lining. The inner duct is placed inside the outer duct and connected by a supporting structure.

[0009] The support structure includes a support bar and a support seat, wherein the support bar is connected to the bottom of the outer duct, and the support seat is located at the central axis of the outer duct and connected to the inner duct.

[0010] The motor and propeller of the drone are arranged in the noise reduction device. The motor is fixed on the support seat and placed on the central axis of the inner duct; the propeller is coaxially connected to the motor and placed on the central axis of the outer duct.

[0011] Preferably, the inner channel back plate and the inner channel curved micro-perforated plate acoustic lining in the inner channel can be flexibly designed in shape according to the actual motor conditions.

[0012] Preferably, the inner channel back plate and the inner channel curved micro-perforated plate sound lining are connected via inner channel side plates or sound-absorbing cotton is filled between the inner channel back plate and the inner channel curved micro-perforated plate sound lining.

[0013] Preferably, a plurality of through holes are provided on the outer duct curved micro-perforated plate sound lining and the inner duct curved micro-perforated plate sound lining, and the plurality of through holes are evenly arranged in a square arrangement or an equilateral triangle arrangement.

[0014] Preferably, the number of the support bars is three or more.

[0015] Compared with the prior art, the invention has the following beneficial effects: the invention provides a UAV duct noise reduction device based on a curved micro-perforated plate acoustic lining. Since the outer duct and the inner duct form a noise reduction structure based on a curved micro-perforated plate acoustic lining, the device can effectively absorb most of the motor noise and the noise generated when the propeller rotates, thereby achieving the noise reduction function. The invention achieves the purpose of reducing the propeller and motor noise of the ducted UAV without increasing too much weight and volume, and has good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0017] Figure 1 It is a cross-sectional schematic diagram of a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining according to the present invention;

[0018] Figure 2 It is a structural schematic diagram of a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining according to the present invention;

[0019] Figure 3 A top view of a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic liner according to the present invention;

[0020] Figure 4 It is a structural schematic diagram of an outer duct curved micro-perforated plate of a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining according to the present invention;

[0021] Figure 5 It is a structural schematic diagram of a ducted curved micro-perforated plate of a ducted UAV noise reduction device based on a curved micro-perforated plate sound lining according to the present invention;

[0022] Figure 6 A comparison chart of the A-weighted sound pressure levels of a ducted UAV noise reduction device based on a curved micro-perforated plate sound lining according to the present invention and a common ducted UAV;

[0023] Figure 7 A comparison diagram of the sound pressure level spectra of a ducted UAV noise reduction device based on a curved micro-perforated plate sound lining according to the present invention and a common ducted UAV;

[0024] The reference numerals in the figure are as follows: 1. outer duct back plate, 2. outer duct curved micro-perforated plate sound lining, 3. inner duct back plate, 4. inner duct curved micro-perforated plate sound lining, 5. support bar, 6. support seat, 7. motor, 8. propeller, 9. inner duct side plate, 10. through hole. DETAILED DESCRIPTION

[0025] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] like Figure 1-5 As shown, a ducted UAV noise reduction device based on a curved micro-perforated plate sound lining includes: a ducted noise reduction structure, a supporting structure and a driving device.

[0028] The duct noise reduction structure includes an outer duct and an inner duct. The outer duct includes an outer duct back plate 1, an outer duct cavity and an outer duct curved micro-perforated plate sound lining 2. The inner duct includes an inner duct back plate 3, an inner duct cavity and an inner duct curved micro-perforated plate sound lining 4. The inner duct is placed inside the outer duct and connected by a supporting structure.

[0029] The support structure includes a support bar 5 and a support seat 6. The support bar 5 is connected to the bottom of the outer duct, and the support seat 6 is located at the central axis of the outer duct and connected to the inner duct.

[0030] The motor 7 and propeller 8 of the drone are arranged in the noise reduction device. The motor 7 is fixed on the support seat 6 and is placed at the central axis of the inner duct; the propeller 8 is coaxially connected to the motor 7 and is placed at the central axis of the outer duct.

[0031] The inner channel back plate 3 and the inner channel curved micro-perforated plate sound lining 4 in the inner channel can be flexibly designed in shape according to the actual conditions of the motor 7.

[0032] The inner channel back plate 3 and the inner channel curved micro-perforated plate sound lining 4 are connected through the inner channel side plate 9 or sound-absorbing cotton is filled between the inner channel back plate 3 and the inner channel curved micro-perforated plate sound lining 4.

[0033] The outer duct curved micro-perforated plate sound lining 2 and the inner duct curved micro-perforated plate sound lining 4 are provided with a plurality of through holes 10 , and the through holes 10 are evenly arranged, such as in a square arrangement or an equilateral triangle arrangement.

[0034] The number of the support bars (5) is three or more.

[0035] Figure 6 and Figure 7The results show that, compared with the ordinary ducted UAV noise reduction device (the ordinary duct compared here uses a duct with a layer of plastic plate or metal plate structure, without the addition of curved ducted micro-perforated plate sound lining), the ducted UAV noise reduction device based on the curved micro-perforated plate sound lining provided by the present invention can achieve a reduction in the A-weighted sound pressure level at different speeds under the premise of the same structural size, and the noise reduction effect of the noise reduction duct on medium and high frequency noise is more significant.

[0036] The present invention provides a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining. Since its outer duct and inner duct form a noise reduction structure based on a curved micro-perforated plate acoustic lining, it can effectively absorb most of the motor noise and the noise generated when the propeller rotates, thereby achieving the noise reduction function. The present invention achieves the purpose of reducing the propeller and motor noise of the ducted UAV without increasing too much weight and volume, and has good application value.

[0037] The above is only a preferred embodiment of the present invention, and its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining, characterized in that include: Duct noise reduction structure and supporting structure; The duct noise reduction structure comprises an outer duct and an inner duct, the outer duct comprises an outer duct back plate (1), an outer duct cavity and an outer duct curved micro-perforated plate sound lining (2), the inner duct comprises an inner duct back plate (3), an inner duct cavity and an inner duct curved micro-perforated plate sound lining (4), and the inner duct is placed inside the outer duct and connected via a supporting structure; The support structure comprises a support bar (5) and a support seat (6), wherein the support bar (5) is connected to the bottom of the outer duct, and the support seat (6) is located at the central axis of the outer duct and is connected to the inner duct.

2. According to claim 1, a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining is characterized by: The inner channel back plate (3) and the inner channel curved micro-perforated plate sound lining (4) are connected via the inner channel side plate (9) or sound-absorbing cotton is filled between the inner channel back plate (3) and the inner channel curved micro-perforated plate sound lining (4).

3. According to claim 1, a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining is characterized by: A plurality of through holes (10) are provided on the outer duct curved micro-perforated plate sound lining (2) and the inner duct curved micro-perforated plate sound lining (4).

4. The noise reduction device for ducted UAV based on curved micro-perforated plate acoustic lining according to claim 3 is characterized by: The through holes (10) are evenly arranged in a square arrangement or an equilateral triangle arrangement.

5. According to claim 1, a ducted UAV noise reduction device based on a curved micro-perforated plate acoustic lining is characterized by: The number of the support bars (5) is three or more.

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