Unmanned aerial vehicle damping device based on mechanical superstructure and unmanned aerial vehicle thereof

Abstract

The invention discloses an unmanned aerial vehicle damping device based on a mechanical superstructure and an unmanned aerial vehicle thereof. The unmanned aerial vehicle damping device comprises vehicle arms, the mechanical superstructure, a clamping mechanism and a lifting mechanism. A mechanical superstructure is sleeved outside one end of the machine arm; the mechanical superstructure is a vibration reduction structure with the negative Poisson's ratio characteristic. The clamping mechanism is clamped outside the mechanical superstructure and is used for fixing the mechanical superstructure at the end part of the vehicle arm; the lifting mechanism is mounted outside the clamping mechanism; due to the fact that the mechanical superstructure has the negative Poisson's ratio characteristic and has excellent impact resistance, the flight safety of the unmanned aerial vehicle can be improved, and the problem that in the prior art, effective vibration reduction control over key vibration sources of motors and rotors of the unmanned aerial vehicle is lacked is practically solved.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and in particular to an unmanned aerial vehicle vibration reduction device based on a mechanical superstructure and the unmanned aerial vehicle. Background Art

[0002] Drones are widely used in military and civilian fields due to their advantages such as strong maneuverability, low cost, simple structure, easy operation and multiple uses. In the civilian field, drones are mainly used to improve efficiency, reduce costs, and perform tasks that require high-altitude perspectives or high-risk environments. In the military field, drones play roles such as reconnaissance, strike, and electronic warfare, and can provide battlefield intelligence and implement precision strikes. Vibration control of drones is crucial to achieving the above functions. During operation, drones experience various types of vibrations, including engine vibration, propeller vibration, aerodynamic vibration, and structural vibration. These vibrations originate from different factors and have an impact on flight performance and system stability. Vibration may have an adverse effect on electronic components, sensors, and batteries, causing these components to fail or degrade in performance. In addition, long-term vibration can cause fatigue in the internal and external structures of drones, leading to cracks or other damage, which in turn affects the overall strength and stability. Strong vibrations can also interfere with the flight control system of drones, affecting their stability and control performance, and easily leading to unstable or out-of-control flight.

[0003] Vibration control is crucial to the flight system of UAVs, and directly affects the stability and safety of the flight of the fuselage. Most of the research on vibration control of UAVs focuses on the vibration reduction of peripheral equipment, and there is less research on vibration reduction control of UAV motors and rotors, which are key vibration sources. Therefore, how to solve this dilemma has become an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a UAV vibration reduction device based on a mechanical superstructure and a UAV thereof, so as to solve the problem that the prior art lacks effective vibration reduction control for the UAV motor and rotor, which are the key vibration sources.

[0005] In order to solve the above technical problems, the present invention provides a vibration reduction device for an unmanned aerial vehicle based on a mechanical superstructure, comprising an arm, a mechanical superstructure, a clamping mechanism and a lifting mechanism; the mechanical superstructure is sleeved on the outside of one end of the arm; the mechanical superstructure is a vibration reduction structure with negative Poisson's ratio characteristics; the clamping mechanism is clamped outside the mechanical superstructure, and the clamping mechanism is used to fix the mechanical superstructure to the end of the arm; the lifting mechanism is installed on the outside of the clamping mechanism.

[0006] In one of the embodiments, the mechanical superstructure includes a plurality of vibration-damping units, and the plurality of vibration-damping units form an arm placement hole, and the machine arm passes through the arm placement hole.

[0007] In one embodiment, the vibration reduction unit includes a central pillar, an oblique pillar, a bent pillar, a side pillar and a connecting pillar; the two central pillars are separated and arranged relative to each other in the same axial manner, and the outer walls of the two central pillars are provided with a plurality of the oblique pillars; the plurality of oblique pillars are separated and arranged around the peripheral wall of the central pillar, and the plurality of oblique pillars are arranged obliquely relative to the axial direction of the central pillar; the bending parts of the plurality of bent pillars are respectively connected to the plurality of oblique pillars, and the side pillars are connected between adjacent bent pillars; the axial directions of the plurality of side pillars are the same as the axial directions of the two central pillars; the plurality of connecting pillars are respectively connected between a plurality of groups of two relatively arranged bent pillars.

[0008] In one embodiment, the bending parts of the plurality of bent pillars are all convex toward the outside of the vibration reduction unit.

[0009] In one embodiment, the plurality of oblique struts are arranged obliquely toward the outside of the vibration reduction unit.

[0010] In one embodiment, the central pillar and the plurality of side pillars are rectangular pillars.

[0011] In one of the embodiments, in the circumferential direction around the central pillar, adjacent vibration-damping units share adjacent side pillars.

[0012] In one embodiment, in the axial direction along the central pillar, adjacent vibration reduction units are connected via the central pillar and a plurality of side pillars.

[0013] In one of the embodiments, the clamping mechanism includes a clamping plate, a fixing plate, a pad, a screw and a nut; the two clamping plates are respectively arranged on opposite sides of the mechanical superstructure; the fixing plate is arranged opposite to one of the clamping plates, and the lifting mechanism is installed on the fixing plate; the pad is clamped between the fixing plate and the clamping plates; the screw passes through the fixing plate, the first clamping plate, the machine arm, the second clamping plate in sequence, and is threadedly connected to the nut.

[0014] In order to solve the above technical problems, the present invention also provides a drone, on which a plurality of the above drone vibration reduction devices are provided, and the plurality of drone vibration reduction devices are circumferentially arranged around the drone.

[0015] The beneficial effects of the present invention are as follows:

[0016] Since the above-mentioned mechanical superstructure has the characteristics of negative Poisson's ratio and excellent impact resistance, it can help improve the flight safety of drones. Specifically, after installing the mechanical superstructure, the vibration peak within the main frequency range of 0-2000Hz of the arm vibration can be effectively reduced. When the motor speed is 5000rpm, the low-frequency main vibration peak is reduced by 69.57% in the horizontal direction and 68.77% in the vertical direction; when the motor speed increases to 6000rpm, the reduction in the horizontal direction can reach 40.94%, and the reduction in the vertical direction can reach 44.87%; therefore, by installing the mechanical superstructure under the motor of the drone, the vibration generated by the motor and propeller can be effectively reduced, significantly improving the flight stability and safety of the drone. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is a schematic structural diagram of a vibration reduction device for a drone provided in an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Schematic diagram of the mechanical superstructure;

[0020] Figure 3 yes Figure 2 Schematic diagram of the vibration reduction unit structure;

[0021] Figure 4 is a schematic diagram of an unmanned structure provided by an embodiment of the present invention;

[0022] Figure 5 It is a diagram of a horizontal vibration measurement experimental device provided by the present invention;

[0023] Figure 6 It is a schematic diagram of the vibration measurement points of a single machine arm in the horizontal direction provided by the present invention;

[0024] Figure 7 It is a diagram of a vertical vibration measurement experimental device provided by the present invention;

[0025] Figure 8 It is a schematic diagram of the vibration measurement points of a single machine arm in the vertical direction provided by the present invention;

[0026] Fig. 9 It is the acceleration time domain response diagram when the horizontal motor speed provided by the present invention is 5000rpm;

[0027] Fig.10 It is the acceleration time domain response diagram when the horizontal motor speed provided by the present invention is 6000rpm;

[0028] Fig.11 It is the acceleration time domain response diagram when the vertical motor speed provided by the present invention is 5000rpm;

[0029] Fig.12 It is the acceleration time domain response diagram when the vertical motor speed provided by the present invention is 6000rpm.

[0030] The reference numerals are as follows:

[0031] 100. UAV vibration reduction device; 200. UAV;

[0032] 10. Arm;

[0033] 20. Mechanical superstructure; 21. Vibration reduction unit; 211. Central pillar; 212. Oblique pillar; 213. Bent pillar; 214. Side pillar; 215. Connecting pillar; 22. Arm hole;

[0034] 30. Clamping mechanism; 31. Clamping plate; 32. Fixing plate; 33. Backing plate; 34. Screw; 35. Nut;

[0035] 40. lift mechanism; 41. motor; 42. rotor;

[0036] 51. Optical vibration isolation platform; 52. Fixed bracket; 53. UAV battery, electric regulator and signal receiver; 54. Laser vibrometer. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0038] The present invention provides a vibration reduction device for unmanned aerial vehicles based on a mechanical superstructure, which can be implemented as follows: Figures 1 to 3 As shown, it includes an arm 10, a mechanical superstructure 20, a clamping mechanism 30 and a lifting mechanism 40; the mechanical superstructure 20 is sleeved on the outside of one end of the arm 10; the mechanical superstructure 20 is a vibration reduction structure with negative Poisson's ratio characteristics; the clamping mechanism 30 is clamped outside the mechanical superstructure 20, and the clamping mechanism 30 is used to fix the mechanical superstructure 20 to the end of the arm 10; the lifting mechanism 40 is installed on the outside of the clamping mechanism 30, specifically, the lifting mechanism 40 includes a motor 41 and a rotor 42, the motor 41 is fixed on the clamping mechanism 30, and is used to drive the rotor 42 to rotate to provide lift.

[0039] Of course, the above structure can be applied to a drone, so the present invention also provides a drone, which can be implemented as Figure 4As shown, the drone 200 is provided with a plurality of the above-mentioned drone vibration reduction devices 100 , and the plurality of drone vibration reduction devices 100 are arranged circumferentially around the drone 200 .

[0040] Since the mechanical superstructure 20 has a negative Poisson's ratio characteristic and excellent impact resistance, it can help improve the flight safety of the drone. Specifically, after installing the mechanical superstructure 20, the vibration peak value of the arm 10 within the main vibration frequency range of 0-2000Hz can be effectively reduced. When the motor 41 speed is 5000rpm, the low-frequency main vibration peak value is reduced by 69.57% in the horizontal direction and 68.77% in the vertical direction; when the motor 41 speed increases to 6000rpm, the reduction in the horizontal direction can reach 40.94%, and the reduction in the vertical direction can reach 44.87%; therefore, by installing the mechanical superstructure 20 under the motor 41 of the drone, the vibration generated by the motor 41 and the propeller can be effectively reduced, significantly improving the flight stability and safety of the drone.

[0041] like Figure 1 and Figure 2 As shown, in this embodiment, the mechanical superstructure 20 includes a plurality of vibration reduction units 21, and the plurality of vibration reduction units 21 surround an arm placement hole 22, through which the organic arm 10 passes, thereby facilitating the installation and fixation between the mechanical superstructure 20 and the organic arm 10.

[0042] Specifically, Figure 1 As shown, the clamping mechanism 30 at this time includes a clamping plate 31, a fixing plate 32, a pad 33, a screw 34 and a nut 35; the two clamping plates 31 are respectively arranged on the opposite sides of the mechanical superstructure 20; the fixing plate 32 is arranged opposite to one of the clamping plates 31, and a lifting mechanism 40 is installed on the fixing plate 32, for example, it can be connected and fixed with the motor 41 of the lifting mechanism 40 by using screws, bolts, etc. through the fixing plate 32; the pad 33 is clamped between the fixing plate 32 and the clamping plate 31; the screw 34 passes through the fixing plate 32, the first clamping plate 31, the arm 10, the second clamping plate 31 in sequence, and is threadedly connected with the nut 35.

[0043] After adopting this setting method, not only can the various components be firmly fixed on the arm 10, but also the mechanical superstructure 20 can be firmly clamped, effectively preventing it from axially rotating around the arm 10; and at this time, multiple groups of screws 34 and nuts 35 can be set to enhance the installation stability, and it is only necessary to ensure that at least one screw 34 passes through the arm 10 and is installed and fixed with the nut 35.

[0044] Among them, the arm 10, the fixing plate 32, the splint 31, and the pad 33 can all be made of carbon fiber materials, and the mechanical superstructure 20 can be made through 3D printing technology, and the printing material is nylon material (the printing material is changeable, and TPU or photosensitive resin, etc. can also be used). At this time, the mechanical superstructure 20 of nylon material accounts for 2% of the total mass of the drone.

[0045] Furthermore, in order to make the mechanical superstructure 20 have the required vibration reduction performance, such as Figure 2 and Figure 3 As shown, in this embodiment, the vibration reduction unit 21 includes a central pillar 211, an oblique pillar 212, a bent pillar 213, a side pillar 214 and a connecting pillar 215; the two central pillars 211 are separated and arranged relative to each other in the same axial direction. For example, in the direction shown in the figure, the two central pillars 211 are arranged relative to each other on the left and right, and the outer walls of the two central pillars 211 are provided with a plurality of oblique pillars 212; the plurality of oblique pillars 212 are separated and arranged around the peripheral wall of the central pillar 211, and the plurality of oblique pillars 212 are arranged obliquely relative to the axial direction of the central pillar 211; the bending parts of the plurality of bent pillars 213 are respectively connected to the plurality of oblique pillars 212, and the side pillars 214 are connected between the adjacent bent pillars 213; the axial directions of the plurality of side pillars 214 are the same as the axial directions of the two central pillars 211; the plurality of connecting pillars 215 are respectively connected between a plurality of groups of two bent pillars 213 arranged relative to each other.

[0046] like Figure 3 As shown, in this embodiment, a plurality of bent pillars 213 are provided, and the bent portions thereof are all convex toward the outside of the vibration reduction unit 21 .

[0047] like Figure 3 As shown, in this embodiment, a plurality of oblique pillars 212 are arranged obliquely toward the outside of the vibration reduction unit 21 .

[0048] like Figure 3 As shown, in this embodiment, the central pillar 211 and the plurality of side pillars 214 are all rectangular pillars.

[0049] like Figure 3 As shown, this embodiment is arranged in the circumferential direction around the central pillar 211 , and adjacent vibration damping units 21 share adjacent side pillars 214 .

[0050] like Figure 3 As shown, this embodiment is arranged in the axial direction along the central pillar 211 , and adjacent vibration reduction units 21 are connected through the central pillar 211 and a plurality of side pillars 214 .

[0051] In order to better verify the application effect of the present invention, a specific experimental method is also provided below.

[0052] 1. Experimental process

[0053] In order to reduce the vibration of the rotor 42 drone, it is necessary to focus on the vibration source, namely the motor 41 and the rotor 42 driven by the motor 41. The motor 41 will vibrate when it is running, and the rotor 42 will generate eddy currents and vibrations during the rotation process, which will affect the drone. Given that each motor 41 is independently installed at the end of the arm 10, a high-performance vibration isolator can be installed at the installation position of each motor 41. This can effectively absorb the vibration of the motor 41 and the rotor 42, and reduce the possibility of it being transmitted to other parts of the body, thereby avoiding the occurrence of resonance of the fuselage structure and improving the safety and service life of the aircraft.

[0054] Therefore, in the experiment, the vibration of the machine arm 10 is measured in the horizontal and vertical directions. The experimental platform is as follows: Figure 5 and Figure 6 As shown. It includes an optical vibration isolation platform 51, a fixed bracket 52, a UAV battery, an electric regulator and a signal receiver 53, a UAV vibration reduction device 100 and a laser vibrometer 54. The process of building the experimental platform is as follows: First, the fixed bracket 52 is firmly mounted on the optical vibration isolation platform 51 by screws, and its height is adjusted to a suitable position; then, the mechanical superstructure 20 is placed under the motor 41 and the rotor 42, and fixed on the arm 10, and then the arm 10 is installed in the reserved card slot of the fixed bracket 52; then, the UAV battery, electric regulator and signal receiver 53 are installed on the fixed bracket 52, and the signal line is correctly connected to the motor 41; finally, the position of the laser vibrometer 54 is adjusted to ensure that its laser point accurately aims at the measurement point of the arm 10.

[0055] To ensure that the laser vibrometer 54 can accurately obtain data during the measurement process, silver-coated reflective paper is pasted on the measurement position of the arm 10. The purpose of this is to enhance the reflection of the laser signal, reduce the diffuse reflection generated by the surface of the measured object, improve the signal-to-noise ratio, and enhance the effect and accuracy of the laser vibrometer 54 in measuring structural vibration. The position of the measurement point is as follows Figure 7 and Figure 8 As shown, we selected four points near the motor 41 as measurement points, marked as points 1, 2, 3 and 4. Among them, point 1 is located closest to the mechanical superstructure 20, with a distance of 3 mm from the mechanical superstructure 20, and the spacing between the four points is 13.5 mm. The measurement points with the same number in the horizontal and vertical directions have the same distance from the motor 41, and they are on the same circumference.

[0056] 2. Experimental Results

[0057] (1) The acceleration time-domain response of the mechanical superstructure 20 is evaluated experimentally. Fig. 9 and Fig.10The time domain response comparison of the vibration acceleration in the horizontal direction before and after the mechanical superstructure 20 is installed at the same measuring point under the same excitation, that is, when the speed of the motor 41 is 5000rpm and 6000rpm, is shown respectively. The red curve represents the vibration condition when the mechanical superstructure 20 is not added, and the blue curve represents the vibration condition after the mechanical superstructure 20 is installed. The time domain signal is collected 1 second after the excitation is applied, and the vibration signal is stabilized. Through the time domain signal analysis, it can be clearly observed that after the mechanical superstructure 20 vibration reduction structure is installed, the vibration acceleration in the horizontal direction is significantly reduced. It is reduced by 86% at 5000rpm and 58% at 6000rpm.

[0058] (2) Fig.11 and Fig.12 The time domain response comparison of the vibration acceleration in the vertical direction before and after the mechanical superstructure 20 is installed at the same measuring point is shown when the motor 41 rotates at 5000rpm and 6000rpm respectively. Through the time domain signal analysis, it can be clearly observed that in the vertical direction, after the mechanical superstructure 20 is installed, the vibration acceleration in the horizontal direction is significantly reduced. It is reduced by 89% at 5000rpm and 64% at 6000rpm.

[0059] The above are preferred embodiments of the present invention. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A vibration reduction device for an unmanned aerial vehicle based on a mechanical superstructure and the unmanned aerial vehicle thereof, characterized in that: It includes the machine arm, mechanical superstructure, clamping mechanism and lifting mechanism; The mechanical superstructure is externally sleeved on one end of the machine arm; The mechanical superstructure is a vibration-damping structure with negative Poisson's ratio characteristics; The clamping mechanism is clamped outside the mechanical superstructure, and the clamping mechanism is used to fix the mechanical superstructure to the end of the machine arm; The lifting mechanism is installed outside the clamping mechanism.

2. The vibration reduction device for unmanned aerial vehicle according to claim 1, characterized in that: The mechanical superstructure comprises a plurality of vibration reduction units, wherein the plurality of vibration reduction units form an arm placement hole, and the machine arm passes through the arm placement hole.

3. The vibration reduction device for unmanned aerial vehicle according to claim 2, characterized in that: The vibration reduction unit includes a central support, an oblique support, a bent support, a side support and a connecting support; The two central pillars are separated and arranged opposite to each other in the same axial direction, and the outer walls of the two central pillars are provided with a plurality of oblique pillars; The plurality of oblique pillars are separately arranged around the peripheral wall of the central pillar, and the plurality of oblique pillars are arranged obliquely relative to the axial direction of the central pillar; The bending parts of the plurality of bent pillars are respectively connected to the plurality of oblique pillars, and the side pillars are connected between adjacent bent pillars; The axial directions of the plurality of side pillars are the same as the axial directions of the two central pillars; A plurality of connecting struts are respectively connected between a plurality of groups of two oppositely arranged bent struts.

4. The vibration reduction device for unmanned aerial vehicle according to claim 3, characterized in that: The bending parts of the plurality of bent pillars all protrude toward the outside of the vibration reduction unit.

5. The vibration reduction device for unmanned aerial vehicle according to claim 3, characterized in that: The plurality of oblique struts are arranged obliquely toward the outer side of the vibration reduction unit.

6. The vibration reduction device for unmanned aerial vehicle according to claim 3, characterized in that: The central pillar and the plurality of side pillars are all rectangular pillars.

7. The vibration reduction device for unmanned aerial vehicle according to claim 3, characterized in that: In a circumferential direction around the central pillar, adjacent vibration damping units share adjacent side pillars.

8. The vibration reduction device for unmanned aerial vehicle according to claim 3, characterized in that: In the axial direction of the central pillar, adjacent vibration-damping units are connected via the central pillar and a plurality of side pillars.

9. The vibration reduction device for unmanned aerial vehicles according to claim 1, characterized in that: The clamping mechanism comprises a clamping plate, a fixing plate, a backing plate, a screw and a nut; The two splints are respectively arranged on two opposite sides of the mechanical superstructure; The fixing plate is arranged opposite to one of the clamping plates, and the lifting mechanism is installed on the fixing plate; The pad is clamped between the fixing plate and the clamping plate; The screw rod passes through the fixing plate, the first clamping plate, the machine arm, and the second clamping plate in sequence and is threadedly connected with the nut.

10. A drone, characterized in that: The drone is provided with a plurality of drone vibration reduction devices according to any one of claims 1 to 9, and the plurality of drone vibration reduction devices are arranged circumferentially around the drone.

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