Damping device for unmanned aerial vehicle

Abstract

The damping device for the unmanned aerial vehicle comprises the unmanned aerial vehicle, the unmanned aerial vehicle is connected with a base through a damping mechanism, the damping mechanism comprises a cross-shaped upper plate and an annular lower plate, and elastic pieces are distributed between the cross-shaped upper plate and the annular lower plate at equal angles. The vibration performance is greatly improved, the steel wire rope compression vibration reduction design is adopted, multi-direction and broadband vibration is effectively attenuated, especially in the middle-high frequency band, the vibration isolation efficiency far exceeds that of a conventional platform, and it is ensured that equipment is stable in the complex flight environment; modularization is achieved, the structure can be adjusted, equipment of different weights and sizes can be flexibly matched, customization is not needed, the use and replacement cost is remarkably reduced, and the device is suitable for multiple scenes such as reconnaissance, surveying and mapping, logistics and low-altitude operation; light high-strength materials (such as magnesium alloy) are selected, a hollow structure is optimized, the load burden is reduced, the endurance and flight performance of the unmanned aerial vehicle is maintained, meanwhile, the structural strength is high, and the service life is prolonged by more than two times.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and more particularly to a vibration reduction device for UAVs. Background Technology

[0002] With the rapid development of drone technology, its applications in military reconnaissance, civilian surveying and mapping, logistics transportation, and low-altitude operations are becoming increasingly widespread, and it is even regarded as the core development direction of the next generation of low-altitude transportation vehicles. Against this backdrop, people have put forward more stringent requirements for the overall quality of drones. They not only need to have sufficient structural strength to adapt to complex flight environments, but also need to have excellent dynamic qualities to ensure operational stability and safety.

[0003] However, vibration remains a key bottleneck restricting the performance improvement of drones during actual flight. On the one hand, for a certain type of hybrid electric drone, the engine itself vibrates significantly, and the existing vibration dampers used at the connection between the engine and the fuselage generally have poor damping effects, causing vibration to be directly transmitted to the fuselage, seriously affecting the normal operation of the carried payload equipment and significantly reducing operational accuracy. On the other hand, for manned multi-rotor drones, vibration not only affects the pilot's control stability and riding comfort, but also causes a series of safety hazards, such as magnetic compass failure, fatigue fracture at structural connections, and loose fasteners. In extreme cases, it can directly lead to the drone going out of control, posing a serious threat to the lives of the crew.

[0004] Currently, most vibration damping devices used in the drone industry are suspended structures. These structures have significant drawbacks in practical applications: firstly, they only dampen vibrations in one direction, resulting in poor adaptability to multi-directional vibrations generated by components such as engines, and limited damping efficiency; secondly, they lack effective protective designs, making them prone to detachment when fatigued due to long-term vibration, potentially leading to secondary accidents such as fuselage structural damage or the fall of loaded equipment. More importantly, traditional suspended vibration damping devices struggle to balance damping effectiveness with structural stability, failing to meet the current demands of drones for high-quality vibration damping solutions. Therefore, developing a more adaptable and safer drone vibration damping device has become an urgent technical challenge for the industry.

[0005] To address the shortcomings of the existing technologies, the vibration damping device proposed in this application has two core advantages: First, it breaks through the traditional design concept of suspension-type vibration damping, transforming the suspension-type device into a compression-type vibration damping device. It achieves vibration damping through compression deformation, which not only has a wider range of applicability and can effectively offset multi-directional vibrations, but also significantly improves the vibration damping effect on the wide frequency range of engine vibrations. Second, it integrates a dedicated limit function. Even if the device is damaged during long-term use, the limit structure can firmly support the key components, preventing the entire device from falling. This fundamentally eliminates secondary safety hazards caused by the failure of the vibration damping device, providing dual protection for the stable flight and safe operation of UAVs. Summary of the Invention

[0006] The purpose of this application is to overcome the shortcomings of existing UAV suspended vibration damping devices, such as poor vibration damping adaptability and easy detachment due to lack of protection, and to provide a UAV vibration damping device with excellent vibration damping effect and high safety.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A vibration damping device for unmanned aerial vehicles (UAVs) includes a UAV connected to a base via a vibration damping mechanism. The vibration damping mechanism includes a cross-shaped upper plate and an annular lower plate. Elastic elements are distributed at equal angles between the cross-shaped upper plate and the annular lower plate. The annular lower plate is connected to the UAV via a first connecting structure, and the cross-shaped upper plate is connected to the base via a second connecting structure. The motion of the elastic element is simplified to a single-degree-of-freedom spring-mass-damped system, and the fundamental vibration is simple harmonic motion. If the vibration displacement of the mass body is x, then the dynamic equation of the mass body m is: Equation 1: ; Let the particular solution of equation 1 be: Equation 2: ; Substituting Equation 2 into Equation 1, we obtain the displacement transmissibility T. r for: ; In the formula, T r B is the absolute transmissivity of displacement; A is the amplitude of the system displacement response; λ is the amplitude of the system input displacement excitation; and λ is the system frequency ratio. ; k is the elastic coefficient, m is the mass, and ξ is the system damping ratio. c is the system damping coefficient.

[0008] Preferably, the elastic element is a wire rope vibration damper, and is made of 304 stainless steel wire rope, woven into a pressed structure with several turns.

[0009] Preferably, the connection structure includes a lower plate column, and both ends of the lower plate column are connected to the annular lower plate and the UAV respectively through connectors.

[0010] Preferably, the second connection structure includes an upper plate column, both ends of which are connected to the cross-shaped upper plate and the base respectively via connectors.

[0011] Preferably, the connector includes a bolt, and the bolt is provided with an elastic washer and a flat washer respectively.

[0012] Preferably, a rubber gasket is provided at the connection between the wire rope vibration damper and the cross-shaped upper plate and the annular lower plate.

[0013] Preferably, the surfaces of both the cross-shaped upper plate and the annular lower plate are anodized. Compared with the prior art, the beneficial effects of the present invention are: Significantly improving vibration isolation performance and ensuring equipment stability. The UAV airborne vibration isolation platform designed in this application addresses the multi-directional, wide-frequency vibration problems caused by propeller rotation, airflow disturbance, and fuselage attitude adjustments during UAV flight. It adopts a steel wire rope vibration damper compression damping mode design, which can effectively attenuate vibration signals in different frequency bands, especially mid-to-high frequency vibrations. The vibration isolation efficiency is significantly improved compared to existing conventional vibration isolation platforms. By greatly reducing the transmission of vibration to the equipment, it ensures that the UAV can maintain a certain degree of stability in complex flight environments (such as low-altitude wind shear, maneuvering flight, and near-ground turbulence).

[0014] Adaptable to multiple equipment types, this platform boasts strong versatility. Its modular and adjustable structural design allows for flexible adaptation to equipment of varying weights and sizes through active adjustment of the upper and lower connecting plates and columns. Compared to existing specialized vibration isolation platforms with limited adaptability, this application eliminates the need for custom-designed vibration isolation structures for different equipment, significantly reducing user operating and replacement costs. It also broadens the platform's application scenarios, making it widely applicable to UAV needs in various fields such as military reconnaissance, civilian surveying and mapping, logistics transportation, and low-altitude operations.

[0015] Lightweight design balances drone range and payload. Considering the drone's sensitivity to the weight of its onboard equipment, it is recommended to use lightweight, high-strength materials (such as magnesium alloys) and a hollow design for structural optimization. This lightweight design reduces the drone's payload burden while minimizing range loss due to additional weight, ensuring the drone can maintain its original flight radius and endurance, meeting the needs of long-duration, long-distance aerial photography missions. Simultaneously, the use of high-strength materials ensures the platform's structural stability and durability, capable of withstanding the impact and vibration loads during drone flight, extending its service life by more than twice that of existing products. Attached Figure Description

[0016] To illustrate the technical solutions in the embodiments of the present invention or the prior art more specifically and intuitively, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0017] Figure 1 This is a schematic diagram showing the connection between the vibration reduction device of the present invention and the drone and equipment; Figure 2 This is a three-dimensional schematic diagram of the present invention; Figure 3 This is an enlarged view of the bolt connection; Figure 4 This is an exploded structural diagram of the present invention; Figure 5 It is the single-degree-of-freedom spring-mass-damping system mentioned in the invention description; Figure 6 It is the curve showing the relationship between the transmission rate and the frequency ratio mentioned in the invention description; Figure 7 It is the simulation analysis report diagram mentioned in the invention description; Figure 8 This is a diagram of the helicopter vibration environment, which is used as a reference in the experiment. Figure 9 This is a table of vibration environment measurement values; Figure 10 It is the vibration test bench control curve formed based on vibration conditions (1).

[0018] In the diagram: 1. UAV; 2. Vibration damping mechanism; 3. Base; 21. Cross-shaped upper plate; 22. Ring-shaped lower plate; 23. Upper plate column; 24. Lower plate column; 25. Wire rope vibration damper; 26. Bolt; 27. Elastic washer; 28. Flat washer. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Example 1: Reference Figures 1-10 A vibration damping device for unmanned aerial vehicles (UAVs) includes a UAV 1. The UAV 1 is connected to a base 3 via a vibration damping mechanism 2. The vibration damping mechanism 2 includes a cross-shaped upper plate 21 and an annular lower plate 22. Elastic elements are distributed at equal angles between the cross-shaped upper plate 21 and the annular lower plate 22. The annular lower plate 22 is connected to the UAV 1 via a first connecting structure, and the cross-shaped upper plate 21 is connected to the base 3 via a second connecting structure. The motion of the elastic element is simplified to a single-degree-of-freedom spring-mass-damped system, and the fundamental vibration is simple harmonic motion. If the vibration displacement of the mass body is x, then the dynamic equation of the mass body m is: Equation 1: ; Let the particular solution of equation 1 be: Equation 2: ; Substituting Equation 2 into Equation 1, we obtain the displacement transmissibility T. r for: ; In the formula, T r B is the absolute transmissivity of displacement; A is the amplitude of the system displacement response; λ is the amplitude of the system input displacement excitation; and λ is the system frequency ratio. ; k is the elastic coefficient, m is the mass, and ξ is the system damping ratio. c is the system damping coefficient.

[0021] T r Displacement transmissibility is an important parameter in the design of vibration isolation systems. The quality of its design directly affects the vibration isolation efficiency and the performance of the product.

[0022] Displacement transmissibility is related to the system damping ratio and the system frequency ratio, and their relationship is as follows: Figure 6 As shown.

[0023] Depend on Figure 6 It can be seen that when λ=1, the displacement transmissibility T r The frequency will greatly exceed 1, and the system will exhibit resonance. If ξ = 0 at this point, the displacement transmissibility will reach infinity. Therefore, in product design, the natural frequency of the vibration isolation system should not be the same as the interference frequency.

[0024] When λ is between 0 and When T is within the range r ≥1; when λ> At that time, T r <1, can achieve the purpose of vibration reduction, as λ increases, T r As the value decreases, the vibration isolation effect becomes better. However, the value should not be too large, because a large value means that the vibration damper is designed to be very soft, with a large static deflection. Consequently, the sway space also needs to be large, and the stability of the system will also deteriorate, making it prone to shaking.

[0025] When λ> When the damping ratio increases, the vibration transmissibility increases, resulting in poor vibration isolation. When the damping decreases, a large vibration will occur when crossing the resonance zone. Therefore, the design of the damping ratio of the vibration isolation system should take into account two aspects: on the one hand, the amplification factor of the system at resonance should be considered, and on the other hand, a satisfactory vibration isolation effect should be achieved.

[0026] Based on the above vibration principle, an experiment was designed to simulate the working environment of a drone by replacing it with a vibration test bench and applying input vibration under certain vibration conditions to the test bench. The upper end of the vibration reduction device of this invention is connected to the vibration test bench, and the lower end is connected to the equipment. The vibration reduction effect is evaluated by measuring the output vibration at the bottom of the equipment and the input vibration on the vibration test bench and comparing the difference between the two curves.

[0027] The vibration conditions are as follows: (1) The test shall be conducted in accordance with the requirements of Class 4 vibration environment in Table 1 of GJB150.16A-2009 "Laboratory Environmental Test Methods for Commercial Equipment - Part 16: Vibration Test". The exposure level shall be adopted according to Figure C.10 of Appendix C, which shows the helicopter vibration environment (see below). Figure 8 The values ​​are shown in Table C.4 (see below). Figure 9 Each axial test lasted 60 minutes. The rotational speed was 33 Hz, and there were 4 blades.

[0028] (2) The vibration test bench control curve (the ideal curve is the middle green curve, and the actual vibration curve is the middle black curve) formed according to the vibration condition (1) is as follows: Figure 10 As shown The simulation analysis report of the vibration isolation system designed based on the above principles is as follows: Figure 10 .

[0029] In this diagram, the horizontal axis represents the vibration frequency, the vertical axis represents the acceleration spectral density, the black curve represents the system's input acceleration spectral density, the red curve represents the output acceleration spectral density in the x-direction, and the purple curve represents the output acceleration spectral density in the y-direction. It can be seen that the vibration damper of this invention has a significant vibration reduction effect in the high-frequency range.

[0030] The four outwardly extending arms of the cross-shaped upper plate 21 are evenly distributed at 90° intervals. A damper mounting hole is provided at the end of each arm for connecting a wire rope damper 25. A column mounting hole is provided at the edge of each arm for connecting an upper plate column 23. The shape of the cross-shaped upper plate 21 is not limited to a cross shape; other shapes can be used, as long as they achieve the function of this invention. In this embodiment, the elastic element is a wire rope vibration damper, specifically a 304 stainless steel wire rope woven into a pressed structure with several turns. The elastic element is not limited to this type of wire rope vibration damper, as long as it can achieve the function of this invention.

[0031] In this embodiment, the first connecting structure includes a lower plate column 24, both ends of which are connected to the annular lower plate 22 and the UAV 1 respectively via connectors. The second connecting structure includes an upper plate column 23, both ends of which are connected to the cross-shaped upper plate 21 and the base 3 respectively via connectors. The connectors include bolts 26, and elastic washers 27 and flat washers 28 are respectively provided on the bolts 26.

[0032] Example 2: Assembly steps of vibration damping device for UAV: Based on the above components, the assembly process of this vibration damping device is as follows: Step 1: Connect the wire rope vibration damper 25 to the cross-shaped upper plate 21. Align the upper connecting ears of the four sets of wire rope vibration dampers 25 with the vibration damper mounting holes of the cross-shaped upper plate 21 support arm, screw in the bolts 26 and tighten them, and install the elastic washers 27 and flat washers 28 to ensure that the wire rope vibration damper 25 is vertically connected to the cross-shaped upper plate 21 without any skewing; Step 2: Connect the wire rope vibration damper 25 to the annular lower plate 22. Connect the annular lower plate 22 to the wire rope vibration damper 25 and screw in the bolt 26 and tighten it. Add the elastic washer 27 and the flat washer 28 to ensure that the wire rope vibration damper 25 and the annular lower plate 22 are connected vertically without any skewing. Step 3: Install the upper plate columns 23. Align the four upper plate columns 23 with the four column mounting holes of the cross-shaped upper plate 21, screw in the bolts 26 and tighten them, and install the elastic washers 27 and flat washers 28 to ensure that the upper plate columns 23 are vertically connected to the cross-shaped upper plate 21 without any skewing. Step 4: Install the lower plate columns 24. Align the four lower plate columns 24 with the four column mounting holes of the annular lower plate 22, screw in the bolts 26 and tighten them, and install the elastic washers 27 and flat washers 28 to ensure that the lower plate columns 24 are vertically connected to the annular lower plate 22 without any skewing. Step 5: Connect the vibration damping mechanism 2 to the base 3. Assemble it with the equipment to be connected using bolts 26 through the internal threaded holes on the upper plate column 23.

[0033] Step 6: Assemble the entire assembly onto the drone 1. Secure the entire assembly to the drone fuselage using bolts through the internal threaded holes on the lower plate column 24. After assembly, manually check the connection stability of each component to ensure that the wire rope vibration damper 25 is not stuck.

[0034] Example 3: Working process of vibration damping device The operation of this device is divided into normal vibration reduction mode and fail-safe mode, as detailed below: 1. Normal vibration reduction state: After the UAV 1 engine starts, the multi-directional vibration generated is transmitted to the four sets of wire rope vibration dampers 25 through the annular lower plate 22. Since the wire rope vibration damper 25 adopts a compression structure, the vibration load will cause the wire rope to undergo elastic deformation. The vibration energy is absorbed through the friction and deformation between the wire rope strands, thereby greatly reducing the vibration transmitted to the cross-shaped upper plate 21 and the fuselage. The central symmetry structure of the cross-shaped upper plate 21 ensures that the four sets of vibration dampers are evenly stressed, avoiding local overload. The annular lower plate 22 ensures that the vibration load is evenly distributed to each vibration damper, improving the overall vibration reduction effect.

[0035] 2. Failure protection status: If the wire rope vibration damper 25 is damaged due to fatigue fracture or loose bolts due to long-term vibration, the annular lower plate 22 will be displaced downward with the vibration of the engine; at this time, the annular lower plate 22 will support the cross-shaped upper plate 21 to prevent the upper plate and the connected equipment from falling off the machine body together, thus eliminating safety hazards.

[0036] Example 4: Optimization Details Supplement To further improve the practicality of the device, the following optimizations have been made in this embodiment: Rubber pads are installed between the metal connecting lugs of the wire rope vibration damper 25 and the connecting surfaces of the cross-shaped upper plate 21 and the annular lower plate 22 to reduce hard contact between metals and avoid secondary vibration. Both the surface of the cross-shaped upper plate 21 and the annular lower plate 22 are anodized to improve corrosion resistance and adapt to complex outdoor flight environments.

[0037] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A vibration damping device for unmanned aerial vehicles (UAVs), comprising a UAV (1), wherein the UAV (1) is connected to a base (3) via a vibration damping mechanism (2), characterized in that, The vibration damping mechanism (2) includes a cross-shaped upper plate (21) and an annular lower plate (22). Elastic elements are distributed at equal angles between the cross-shaped upper plate (21) and the annular lower plate (22). The annular lower plate (22) is connected to the UAV (1) through a connecting structure one, and the cross-shaped upper plate (21) is connected to the base (3) through a connecting structure two. The motion of the elastic element is simplified to a single-degree-of-freedom spring-mass-damped system, and the fundamental vibration is simple harmonic motion. If the vibration displacement of the mass body is x, then the dynamic equation of the mass body m is: Equation 1: ; Let the particular solution of equation 1 be: Equation 2: ; Substituting Equation 2 into Equation 1, we obtain the displacement transmissibility T. r for: ； In the formula, T r B is the absolute transmissivity of displacement; A is the amplitude of the system displacement response; λ is the amplitude of the system input displacement excitation; and λ is the system frequency ratio. ; k is the elastic coefficient, m is the mass, and ξ is the system damping ratio. c is the system damping coefficient.

2. The vibration damping device for unmanned aerial vehicles according to claim 1, characterized in that, The elastic element is a wire rope vibration damper, and it is made of 304 stainless steel wire rope, woven into a pressed structure with several turns.

3. A vibration damping device for unmanned aerial vehicles according to claim 2, characterized in that, The connection structure includes a lower plate column (24), and both ends of the lower plate column (24) are connected to the annular lower plate (22) and the UAV (1) respectively through connectors.

4. A vibration damping device for unmanned aerial vehicles according to claim 3, characterized in that, The second connection structure includes an upper plate column (23), both ends of which are connected to the cross-shaped upper plate (21) and the base (3) respectively through connectors.

5. A vibration damping device for unmanned aerial vehicles according to claim 4, characterized in that, The connector includes a bolt (26), on which an elastic washer (27) and a flat washer (28) are respectively provided.

6. A vibration damping device for unmanned aerial vehicles according to claim 4, characterized in that, Rubber pads are provided at the connection points of the wire rope vibration damper (25) with the cross-shaped upper plate (21) and the annular lower plate (22).

7. A vibration damping device for a drone according to claim 4, characterized in that, The surfaces of the cross-shaped upper plate (21) and the annular lower plate (22) are both anodized.

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