A UAV vibration reduction device based on mechanical superstructure and its UAV

Abstract

The present invention discloses a vibration reduction device for an unmanned aerial vehicle (UAV) based on a mechanical superstructure and the UAV thereof, comprising an arm, a mechanical superstructure, a clamping mechanism and a lifting mechanism; the mechanical superstructure is sheathed on the outside of one end of the arm; the mechanical superstructure is a vibration reduction structure with a negative Poisson's ratio characteristic; 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; since the above-mentioned mechanical superstructure has the negative Poisson's ratio characteristic and has excellent impact resistance, it can help to improve the flight safety of the UAV, thereby effectively solving the problem that the prior art lacks effective vibration reduction control for the UAV motor and rotor, which are key vibration sources.

Description

Technical Field

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

[0002] Drones (UAVs) are widely used in both military and civilian applications due to their high maneuverability, low cost, simple structure, ease of operation, and reusability. In the civilian sector, UAVs are primarily used to improve efficiency, reduce costs, and perform missions requiring high-altitude perspectives or in high-risk environments. In the military, UAVs perform reconnaissance, strike, and electronic warfare roles, providing battlefield intelligence and conducting precision strikes. Vibration control is crucial to achieving these functions. UAVs experience various types of vibration during operation, including engine vibration, propeller vibration, aerodynamic vibration, and structural vibration. These vibrations originate from various factors and affect flight performance and system stability. Vibration can adversely affect electronic components, sensors, and batteries, leading to failure or performance degradation. Furthermore, long-term vibration can cause fatigue in the internal and external structures of UAVs, leading to cracks or other damage, compromising overall strength and stability. Severe vibration can also interfere with a UAV's flight control system, compromising stability and maneuverability, and potentially leading to flight instability or loss of control.

[0003] Vibration control is crucial for drone flight systems, directly impacting flight stability and safety. While most research on drone vibration control focuses on vibration reduction in peripheral devices, relatively little research has focused on vibration reduction control of the drone's motors and rotors, the key vibration sources. Therefore, resolving this dilemma has become a pressing issue. 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 the 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 sheathed on the outside of one end of the arm; the mechanical superstructure is a vibration reduction structure with a negative Poisson's ratio characteristic; 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 embodiment, 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 damping 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 at an angle 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; and 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 damping unit.

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

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

[0011] In one embodiment, in a 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 damping units are connected via the central pillar and a plurality of side pillars.

[0013] In one embodiment, the clamping mechanism includes a splint, a fixed plate, a pad, a screw and a nut; the two splints are respectively arranged on opposite sides of the mechanical superstructure; the fixed plate is arranged opposite to one of the splints, and the lifting mechanism is installed on the fixed plate; the pad is clamped between the fixed plate and the splint; the screw passes through the fixed plate, the first splint, the machine arm, the second splint 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 arranged circumferentially around the drone.

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

[0016] Because the aforementioned mechanical superstructure has a 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 of the arm vibration within the main frequency range of 0-2000Hz can be effectively reduced. At a motor speed of 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 is increased 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 a mechanical superstructure under the drone's motor, the vibration generated by the motor and propeller can be effectively reduced, significantly improving the drone's flight stability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the structure of the UAV vibration reduction device provided by 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 This is a schematic diagram of an unmanned structure provided by an embodiment of the present invention;

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

[0023] Figure 6 This is a schematic diagram of the horizontal single-arm vibration measurement point provided by the present invention;

[0024] Figure 7 1 is a diagram of a vertical vibration measurement experimental device provided by the present invention;

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

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

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

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

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

[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. Diagonal 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, electronic speed controller 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 with reference to the accompanying drawings in the embodiments of the present invention.

[0038] The present invention provides a vibration reduction device for UAV based on 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 lift mechanism 40; the mechanical superstructure 20 is sheathed on one end of the arm 10; the mechanical superstructure 20 is a vibration-damping structure with a negative Poisson's ratio characteristic; 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 lift mechanism 40 is installed on the outside of the clamping mechanism 30. Specifically, the lift mechanism 40 includes a motor 41 and a rotor 42. The motor 41 is fixed to 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] Because the mechanical superstructure 20 has a negative Poisson's ratio and excellent impact resistance, it can help improve the flight safety of drones. Specifically, after installing the mechanical superstructure 20, the vibration peak 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 is reduced by 69.57% in the horizontal direction and 68.77% in the vertical direction. When the motor 41 speed is increased to 6000rpm, the horizontal reduction can reach 40.94% and the vertical reduction can reach 44.87%. Therefore, by installing the mechanical superstructure 20 below the drone's motor 41, the vibration generated by the motor 41 and propeller can be effectively reduced, significantly improving the drone's flight stability and safety.

[0041] like Figure 1 and Figure 2 As shown, in this embodiment, the mechanical superstructure 20 includes a plurality of vibration-damping units 21 , and the plurality of vibration-damping units 21 are surrounded by an arm 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, such as 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 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 to 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 to the nut 35.

[0043] After adopting this setting method, not only can the various components be firmly fixed on the arm 10, but the mechanical superstructure 20 can also be firmly clamped, effectively preventing it from rotating axially around the arm 10; and at this time, multiple sets of screws 34 and nuts 35 can be set to enhance the installation stability. 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, fixing plate 32, splint 31, and pad 33 can all be made of carbon fiber materials, while 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, this embodiment provides a vibration reduction unit 21 including 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 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; and the plurality of connecting pillars 215 are respectively connected between a plurality of groups of two oppositely arranged bent pillars 213.

[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 supports 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 a 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 along the axial direction of the central pillar 211 , and adjacent vibration damping units 21 are connected via 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 provided below.

[0052] 1. Experimental Procedure

[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 generate vibration when it is running, and the rotor 42 will generate eddy currents and vibrations during the rotation process, which will affect the drone. Since 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 fuselage structural resonance 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 drone battery, an electronic speed controller, and a signal receiver 53, a drone vibration reduction device 100, and a laser vibrometer 54. The experimental platform construction process is as follows: First, securely mount the fixed bracket 52 on the optical vibration isolation platform 51 with screws and ensure its height is adjusted to the appropriate position. Next, place the mechanical superstructure 20 below the motor 41 and rotor 42 and secure it to the arm 10. The arm 10 is then installed into the reserved slot on the fixed bracket 52. Next, install the drone battery, electronic speed controller, and signal receiver 53 on the fixed bracket 52, and ensure that the signal cable is properly connected to the motor 41. Finally, adjust the position of the laser vibrometer 54 to ensure its laser point accurately targets the measurement point on 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. This is done 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 effectiveness and accuracy of the laser vibrometer 54 in measuring structural vibration. The location 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. Point 1 is located closest to the mechanical superstructure 20, with a distance of 3 mm from the mechanical superstructure 20. The spacing between the four points is 13.5 mm. The measurement points with the same number in the horizontal and vertical directions are at the same distance from the motor 41 and are located on the same circumference.

[0056] 2. Experimental Results

[0057] (1) The acceleration time-domain response of the mechanical superstructure 20 is evaluated experimentally. Figure 9 and Figure 10The figures show a comparison of the time domain response of the vibration acceleration in the horizontal direction before and after the mechanical superstructure 20 is installed at the same measurement point under the same excitation, that is, when the motor 41 rotates at 5000 rpm and 6000 rpm. The red curve shows the vibration without the mechanical superstructure 20, and the blue curve shows the vibration after the mechanical superstructure 20 is installed. The time domain signal is collected 1 second after the excitation is applied, and the vibration signal stabilizes. 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 5000 rpm and 58% at 6000 rpm.

[0058] (2) Figure 11 and Figure 12 The time-domain response comparison of vertical vibration acceleration at the same measurement point before and after the mechanical superstructure 20 was installed is shown, respectively, at motor 41 speeds of 5000 rpm and 6000 rpm. Time-domain signal analysis clearly shows a significant decrease in horizontal vibration acceleration in the vertical direction after the mechanical superstructure 20 was installed. The decrease was 89% at 5000 rpm and 64% at 6000 rpm.

[0059] The above is a preferred embodiment of the present invention. It should be pointed out 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, characterized in that: It includes the machine arm, mechanical superstructure, clamping mechanism and lifting mechanism; One end of the arm is covered with the mechanical superstructure; 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; The mechanical superstructure includes a plurality of vibration-damping units, wherein the plurality of vibration-damping units form an arm placement hole, and the machine arm passes through the arm placement hole; 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 opposite to each other in the same axial direction, and the outer walls of the two central pillars are provided with a plurality of the 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 the bent pillars are respectively connected to the plurality of the oblique pillars, and the side pillars are connected between adjacent bent pillars; The axial directions of the plurality of side pillars are all 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.

2. The UAV vibration reduction device according to claim 1, characterized in that: The bending parts of the plurality of bent pillars all protrude toward the outside of the vibration reduction unit.

3. The UAV vibration reduction device according to claim 1, characterized in that: The plurality of oblique supports are arranged obliquely toward the outside of the vibration damping unit.

4. The UAV vibration reduction device according to claim 1, characterized in that: The central pillar and the plurality of side pillars are all rectangular pillars.

5. The UAV vibration reduction device according to claim 1, characterized in that: In a circumferential direction around the central pillar, adjacent vibration damping units share adjacent side pillars.

6. The UAV vibration reduction device according to claim 1, 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.

7. The UAV vibration reduction device according to claim 1, characterized in that: The clamping mechanism includes a clamping plate, a fixing plate, a backing plate, a screw and a nut; The two splints 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 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 then threadedly connected to the nut.

8. 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 7, and the plurality of drone vibration reduction devices are arranged circumferentially around the drone.

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