Unmanned aerial vehicle vibration suppression structure based on localized resonance metamaterials

Abstract

The utility model relates to the technical field of unmanned plane, concretely provides unmanned plane vibration suppression method and structure based on local area resonance metamaterial, including main body arch frame and shallow arch curved beam, the curved inside of shallow arch curved beam with the curved inside of main body arch frame opposite setting, the both ends of shallow arch curved beam with the curved inside of main body arch frame fixed connection and form the quasi zero stiffness single oscillator with integrated structure, the end face of main body arch frame both ends is in the same plane, the position of end face of main body arch frame both ends close to the center still is provided with screw hole, through setting up curved beam combination oscillator with shallow arch curved beam, solved the problem that unmanned plane traditional oscillator is difficult to realize low inherent frequency vibration isolation and poor spatial adaptability.

Description

Technical Field

[0001] This utility model relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to a method and structure for UAV vibration suppression based on local resonant metamaterials. Background Technology

[0002] With the continuous development of science and technology, drones have begun to be widely used in life, such as aerial photography, geographic surveying, power line inspection, agricultural plant protection, and military reconnaissance. These diverse applications present them with severe challenges from complex vibration environments. Vibrations mainly originate from the power system (periodic excitation generated by the high-speed rotation of the propeller) and aerodynamic disturbances during flight attitude adjustments, including low-frequency continuous vibrations and high-frequency random vibrations. These vibrations not only reduce flight stability and control precision but also more easily lead to measurement distortion, structural fatigue, or even failure of airborne precision equipment (such as optical pods and lidar). Mechanical structural vibrations are essentially transmitted in the form of elastic waves within the structure. The concept of "metamaterials" has provided a new opportunity for vibration isolation technology. Research has shown that some mechanical metamaterials have special frequency ranges within which elastic wave propagation is suppressed. Such frequency ranges are called "band gaps," and their position, width, and depth correspond to the frequency range position and width of vibration isolation and the ability to suppress wave propagation, respectively. These band gaps can be controlled through material or structural parameters. Currently, elastic wave suppression mainly relies on two band gap formation mechanisms—Bragg scattering and local resonance. However, the Bragg scattering bandgap is controlled by the Bragg condition, which depends on the lattice constant. The lattice constant is inversely proportional to the center frequency of the bandgap, which means that a large lattice constant is required to realize a low-frequency Bragg scattering bandgap. In addition, traditional oscillators also have inherent frequency limitations, making it difficult to meet the vibration isolation requirements of small volume and low frequency range. Utility Model Content

[0003] To address the problems of traditional oscillators in UAVs being unable to achieve low natural frequency vibration isolation and having poor spatial adaptability, this invention provides a method and structure for UAV vibration suppression based on local resonant metamaterials to solve the above problems.

[0004] The technical solution adopted by this utility model to solve its technical problem is: a method and structure for vibration suppression of unmanned aerial vehicles based on local resonant metamaterials, including a main arch frame and a shallow arched beam. The inner curved side of the shallow arched beam is opposite to the inner curved side of the main arch frame. The two ends of the shallow arched beam are fixedly connected to the inner curved side of the main arch frame to form a quasi-zero stiffness single vibrator with an integrated structure. The end faces of the two ends of the main arch frame are located in the same plane. Screw holes are also provided near the center of the end faces of the two ends of the main arch frame.

[0005] Preferably, multiple quasi-zero stiffness single vibrators are provided, and the end faces of the main arch frames of any two quasi-zero stiffness single vibrators can fit together to form a curved beam combined vibrator. Multiple curved beam combined vibrators can be fixed inside the arm of the UAV and located on the same axis.

[0006] Preferably, the outer side of the shallow arched curved beam protrudes outward near the middle to form a square boss.

[0007] Preferably, the center of the curved beam combined oscillator is detachably connected to an additional mass block, and the two ends of the additional mass block are respectively engaged and fixed with the two square bosses.

[0008] Preferably, multiple additional mass blocks are provided, each with a different mass, and the center of the curved beam combined oscillator can only be detachably connected to one of the additional mass blocks.

[0009] Preferably, the main arch frame is an arc-shaped arch frame structure.

[0010] Preferably, the main arch frame is a rectangular arch frame structure.

[0011] A method for suppressing the vibration of a drone based on a local resonant metamaterial includes the drone vibration suppression structure based on the local resonant metamaterial as described above, and further includes the following steps: S1, selecting multiple quasi-zero stiffness single oscillators according to the length of the drone's arm; S2, combining the multiple quasi-zero stiffness single oscillators in pairs and bonding them together to form an integral structure; S3, installing additional mass blocks on the square protrusions at the center of the two quasi-zero stiffness single oscillators to form a curved beam combined oscillator; S4, fixing the multiple curved beam combined oscillators at equal intervals inside the drone's arm.

[0012] The beneficial effects of this utility model are, firstly, that by setting a quasi-zero stiffness single vibrator with a shallow arched curved beam, the problems of traditional UAV vibrators being unable to achieve low natural frequency vibration isolation and having poor spatial adaptability are solved.

[0013] Secondly, two quasi-zero stiffness single oscillators are combined to form a curved beam composite oscillator. The curved beam composite oscillator has high static stiffness and low dynamic stiffness. That is, under no external load conditions, it has high static stiffness to ensure its high load-bearing capacity. When it is compressed to the static equilibrium position due to the load, its dynamic stiffness drops significantly to close to zero. This characteristic can effectively solve the problem of limiting the natural frequency of local oscillators, thereby achieving a low-frequency bandgap. By making full use of the advantages of quasi-zero stiffness technology, the UAV has excellent vibration isolation effect in the low-frequency range, enabling the UAV to adapt to complex vibration environments.

[0014] Third, the curved beam combined vibrator is integrated and has a simple structure. By installing the curved beam combined vibrator with shallow arched curved beam in the drone arm, the problems of traditional drone vibrators being difficult to achieve low natural frequency vibration isolation and poor spatial adaptability are solved. Attached Figure Description

[0015] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the main arch frame of Embodiment 1 of this utility model; Figure 2 This is a schematic diagram of the shallow arch curved beam according to Embodiment 1 of this utility model; Figure 3 This is a schematic diagram of the structure of the additional mass block in Embodiment 1 of this utility model; Figure 4 This is a schematic diagram of the screw hole structure of Embodiment 1 of this utility model; Figure 5 This is a schematic diagram of the installation position of the curved beam combined vibrator according to Embodiment 1 of this utility model; Figure 6 This is a schematic diagram of the structure of the combined arm and curved beam vibrator of Embodiment 1 of this utility model; Figure 7 This is a schematic diagram of the main arch frame of Embodiment 2 of this utility model; Figure 8 This is a schematic diagram of the shallow arch curved beam according to Embodiment 2 of this utility model; Figure 9 This is a schematic diagram of the structure of the additional mass block in Embodiment 2 of this utility model; Figure 10 This is a schematic diagram of the screw hole structure in Embodiment 2 of this utility model.

[0017] Reference numerals in the attached diagram: 1. Shallow arched curved beam; 2. Additional mass block; 3. Screw hole; 4. Curved beam combined vibrator; 5. Machine arm; 6. Main arch frame; 7. Square boss. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] like Figures 1-6 As shown, this utility model provides an embodiment of a method and structure for vibration suppression of unmanned aerial vehicles based on local resonant metamaterials, including a main arch frame 6 and a shallow arch curved beam 1. The shallow arch curved beam 1 is an arc-shaped structure. The inner curved side of the shallow arch curved beam 1 is opposite to the inner curved side of the main arch frame 6. The two ends of the shallow arch curved beam 1 are fixedly connected to the inner curved side of the main arch frame 6 to form a quasi-zero stiffness single vibrator with an integrated structure. The end faces of the two ends of the main arch frame 6 are located in the same plane.

[0021] Multiple quasi-zero stiffness single vibrators are provided. The end faces of the main arch frame 6 of any two quasi-zero stiffness single vibrators can be fitted together to form a curved beam combined vibrator 4. When two quasi-zero stiffness single vibrators are pressed together until their end faces are fitted together, their displacement reaches the quasi-zero stiffness working area, which improves the static bearing capacity of the curved beam combined vibrator 4 and gives the curved beam combined vibrator 4 quasi-zero stiffness characteristics. The fitting points of two quasi-zero stiffness single vibrators are bonded and fixed. Multiple curved beam combined vibrators 4 can be fixed inside the arm 5 of the UAV and located on the same axis.

[0022] Under no external load conditions, i.e. when the UAV is not started, the curved beam combined vibrator 4 has high static characteristics to ensure high load-bearing capacity and small static displacement. When the curved beam combined vibrator 4 is compressed to the static equilibrium position due to the load, i.e. after the UAV is started, the dynamic stiffness of the curved beam combined vibrator 4 drops significantly to close to zero, which solves the problem of limiting the natural frequency of the local vibrator, thereby achieving low-frequency bandgap vibration isolation.

[0023] The outer side of the shallow arched curved beam 1 protrudes outward near the middle to form a square boss 7.

[0024] An additional mass block 2 is detachably connected to the center of the curved beam combined vibrator 4. The two ends of the additional mass block 2 are respectively engaged and fixed with two square bosses 7.

[0025] Multiple additional mass blocks 2 are provided, each with a different mass. The center of the curved beam combined oscillator 4 can only be detachably connected to one of the additional mass blocks 2. By using additional mass blocks 2 of different masses, the bandgap frequency of the curved beam combined oscillator 4 can be reduced, effectively achieving low-frequency vibration isolation for the UAV.

[0026] The main arch frame 6 is an arc-shaped arch frame structure to accommodate the cylindrical drone arm 5, so that the outer wall of the curved beam combined vibrator 4 can fit tightly with the inner wall of the drone arm 5. Screw holes 3 are also provided at the end faces of both ends of the main arch frame 6 near the center. A single screw can be used to pass through the screw hole of the combined curved beam combined vibrator 4 and the arm to fix the curved beam combined vibrator 4 to the arm, making it convenient to fix the curved beam combined vibrator 4.

[0027] like Figures 7-10 As shown, this utility model provides a second embodiment of a method and structure for vibration suppression of unmanned aerial vehicles (UAVs) based on local resonant metamaterials. The difference between the second embodiment and the first embodiment is that the main arch frame 6 is a rectangular arch frame structure to accommodate the square column-shaped UAV arm 5. By setting different shapes of main arch frames 6, the curved beam combined vibrator 4 can be fixed in the arm 5 of various UAVs, achieving an integrated fixing effect. This meets the requirements of UAVs for compact layout and lightweight design, and fully utilizes the advantages of quasi-zero stiffness technology to enable the UAV to have excellent vibration isolation effect in the low frequency range, improving the UAV's ability to adapt to complex vibration environments.

[0028] A method for vibration suppression of unmanned aerial vehicles (UAVs) based on local resonant metamaterials, comprising the above-mentioned UAV vibration suppression structure based on local resonant metamaterials, and further comprising the following steps: S1. Select multiple quasi-zero stiffness single vibrators according to the length of the UAV's arm 5; S2. Multiple quasi-zero stiffness single oscillators are combined in pairs to form an integral structure. Since the shallow arch curved beam 1 of the uncombined quasi-zero stiffness single oscillators needs to have a certain displacement in order to reach the quasi-zero stiffness working area, if only quasi-zero stiffness single oscillators are used, a certain pressure needs to be applied to the quasi-zero stiffness single oscillators at all times. In this embodiment, two quasi-zero stiffness single oscillators are combined. By utilizing the geometric symmetry of the structure, when the two quasi-zero stiffness single oscillators are squeezed together to the closed gap, the displacement of the shallow arch curved beam 1 reaches the quasi-zero stiffness working area. In this way, even without relying on the gravity of the mass block, the shallow arch curved beam 1 of the two quasi-zero stiffness single oscillators can have a certain displacement to obtain the final curved beam combined oscillator 4 with quasi-zero stiffness characteristics. S3. Install additional mass blocks 2 on the square bosses 7 at the centers of the two quasi-zero stiffness single oscillators to form a curved beam combined oscillator 4. By having the additional mass blocks 2 and the square bosses 7 abut against each other, a certain pressure is applied to the shallow arch curved beam 1, so that the curved beam combined oscillator 4 can reach the quasi-zero stiffness working area. By using additional mass blocks 2 of different masses, the bandgap frequency of the curved beam combined oscillator 4 can be reduced, solving the problem of limiting the natural frequency of low local oscillators, thereby achieving low-frequency bandgap vibration isolation. S4. Fix multiple curved beam combined vibrators 4 at equal intervals inside the drone's arm 5. This can be done by using screw holes 3 and screws to lock the multiple curved beam combined vibrators 4 inside the drone's arm 5, or by using elastic clips or other mechanical locking structures to fix the multiple curved beam combined vibrators 4. It is only necessary to ensure that the curved beam combined vibrators 4 cannot fall off inside the drone's arm 5. The additional mass blocks of all the curved beam combined vibrators 4 set on the arm 5 of a single drone are the same. By using an appropriate number of curved beam combined vibrators 4, the overall vibration isolation performance of the system can be improved.

[0029] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. The above are only preferred embodiments of this application. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the concept and technical solution of the utility model to other occasions without modification, should all be considered within the scope of protection of this application.

Claims

1. A vibration suppression structure for unmanned aerial vehicles based on locally resonant metamaterials, characterized in that: It includes a main arch frame (6) and a shallow arch curved beam (1). The inner curved side of the shallow arch curved beam (1) is opposite to the inner curved side of the main arch frame (6). The two ends of the shallow arch curved beam (1) are fixedly connected to the inner curved side of the main arch frame (6) to form a quasi-zero stiffness single vibrator with an integral structure. The end faces of the two ends of the main arch frame (6) are located in the same plane. Screw holes (3) are also provided near the center of the end faces of the two ends of the main arch frame (6).

2. The metamaterial-based drone vibration suppression structure of claim 1, wherein: Multiple quasi-zero stiffness single vibrators are provided. The end faces of the main arch frame (6) of any two quasi-zero stiffness single vibrators can fit together to form a curved beam combined vibrator (4). Multiple curved beam combined vibrators (4) can be fixed inside the arm (5) of the UAV and located on the same axis.

3. The metamaterial-based drone vibration suppression structure of claim 2, wherein: The shallow arched curved beam (1) protrudes outward near the middle on the curved outer side to form a square boss (7).

4. The metamaterial-based drone vibration suppression structure of claim 3, wherein: The center of the curved beam combined vibrator (4) is detachably connected to an additional mass block (2), and the two ends of the additional mass block (2) are respectively engaged and fixed with the two square bosses (7).

5. The metamaterial-based drone vibration suppression structure of claim 4, wherein: Multiple additional mass blocks (2) are provided, each with a different mass. The center of the curved beam combined oscillator (4) can only be detachably connected to one of the additional mass blocks (2).

6. The UAV vibration suppression structure based on locally resonant metamaterials as described in claim 3, characterized in that: The main arch frame (6) is an arc-shaped arch frame structure.

7. The metamaterial-based drone vibration suppression structure of claim 3, wherein: The main arch frame (6) is a rectangular arch frame structure.

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