WO2018157633A1

WO2018157633A1 - Shock absorber, pan-tilt and unmanned aerial vehicle

Info

Publication number: WO2018157633A1
Application number: PCT/CN2017/113051
Authority: WO
Inventors: 唐国金; 马维力
Original assignee: 深圳市道通智能航空技术有限公司; 湖南省道通科技有限公司
Priority date: 2017-03-03
Filing date: 2017-11-27
Publication date: 2018-09-07
Also published as: CN106838117A

Abstract

Provided is a shock absorber (100), comprising a connecting portion (102) and buffering portions (101) respectively located on either end of the connecting portion, wherein the cross-sectional size of the shock absorber gradually decreases along the direction from a buffering portion to the connecting portion. Further provided are a pan-tilt (10) having the shock absorber, and an unmanned aerial vehicle (20). The middle portion of the shock absorber if of a smaller size than the two ends, thereby reducing the volume and the mass of the middle portion, such that the shock absorber has a higher flexibility and the inherent frequency corresponding to a second-order vibration mode of the shock absorber is greatly improved, thus avoiding the frequency coupling, in a high-frequency portion, between the shock absorber and a vehicle body. The shock absorber can effectively isolate the high-frequency vibration from the vehicle body so that the picture taken by a pan-tilt camera is sharper and more stable.

Description

Shock absorbers, pan/tilt and drones

Technical field

The present application relates to the field of drones, and more particularly to a vibration damping member, a cloud platform and a drone using the vibration damping member.

Background technique

With the increasing popularity of drones, aerial photography has become commonplace. UAV aerial photography is achieved by mounting a camera at the bottom of the drone's fuselage. The camera is mounted on the bottom of the drone's fuselage through a gimbal connection. The prior art gimbal includes a vibration damping member, and the vibration damping member is made of a flexible material such as silicone rubber or rubber, so that a flexible connection is formed between the body and the camera, which acts as a vibration isolation, so that the camera takes a clear picture.

In general, the higher the compliance of the vibration damper, the better the vibration isolation effect. However, the existing vibration damper, as shown in Fig. 1, due to the structure and shape limitation, the natural frequency corresponding to the second-order mode is correspondingly reduced while the compliance is sufficiently low. The natural frequency corresponding to the second-order mode is frequency-coupled with the vibration component of the fuselage in the high-frequency range, resulting in resonance in the high-frequency range, so that the vibration of the pan-tilt is amplified, so that the expected vibration isolation effect cannot be achieved. As shown in Fig. 2 to Fig. 6, the acceleration response at the connection between the vibration damper and the fuselage is used as the vibration input, and the acceleration response at the connection between the cloud platform and the camera is used as the vibration output to perform the vibration test on the unmanned aerial platform. As shown in Figure 2 to Figure 4, after testing and analysis, the vibration of the UAV pan/tilt in the interval of 210Hz~300Hz is the main part of its vibration. As shown in Fig. 5-6, the degree of vibration attenuation of the UAV pan/tilt in the interval of 210 Hz to 300 Hz is significantly smaller than that of other frequency ranges, and there is a peak near 245 Hz. The test results show that the gimbal has a natural frequency near the frequency point of 245 Hz, which is coupled with the frequency of the input excitation of the vibration source to generate resonance, which leads to vibration amplification.

Therefore, although the existing vibration absorbing members isolate most of the high-frequency vibration transmitted from the fuselage, all the high-frequency vibrations cannot be completely avoided, and the high-frequency vibration of the pan/tilt causes the camera to take a "tilt". The phenomenon of “swinging” or “partial exposure” seriously affects the quality of shooting.

Summary of the invention

According to the deficiencies of the above prior art, it is necessary to provide a vibration absorbing member having high compliance and high natural frequency corresponding to the second-order mode, capable of effectively isolating high-frequency vibration, and a pan and drone using the damper .

The present application provides a vibration damping member including a connecting portion and a buffer portion respectively located at both ends of the connecting portion, the cross-sectional dimension of the vibration damping member gradually decreasing in a direction from the buffer portion toward the connecting portion small.

In one implementation, the buffer portions are symmetrically disposed at both ends of the connecting portion.

Optionally, the buffer portion has a truncated cone shape.

Optionally, at least one of the outer surface and the inner surface of the buffer portion is stepped.

Optionally, the buffer portion is hemispherical.

Optionally, the buffer portion smoothly transitions to the connecting portion.

Optionally, the outer contour shape of the vibration damper is a hyperboloid.

Optionally, the vibration damping member is filled with a damping material.

The application further provides a pan/tilt head, comprising a first connecting plate, a second connecting plate and a vibration damping member, wherein the first connecting plate and the second connecting plate are connected by the vibration damping member, the vibration damping member It is the vibration damper described above.

The application also provides a drone comprising a fuselage and the above-mentioned pan/tilt connected to the fuselage.

The beneficial effects of the application are:

The shock absorbing member provided by the present application has a cross-sectional dimension of the connecting portion at the middle portion smaller than that of the buffer portion at both ends, and reduces the central volume and reduces the central mass compared with the existing structure. The vibration damper has higher flexibility and greatly increases the natural frequency corresponding to the second-order mode of the damper, avoiding frequency coupling between the damper and the fuselage in the high-frequency part, so that the pan-tilt is in the range of 50 Hz to 300 Hz. The vibration inside can be reduced by more than 50%, effectively isolating the high-frequency vibration from the body, making the picture taken by the camera clearer.

DRAWINGS

1 is a schematic structural view of a conventional vibration damper;

2, 3 and 4 are vibration response diagrams (time domain portions) of the pan-tilt output in the prior art under vibration of 5 to 300 Hz;

5 and FIG. 6 are vibration input and output response diagrams (frequency domain portions) of a prior art gimbal under vibration of 5 to 300 Hz;

7 is a perspective structural view of a vibration damper embodiment 1 of the present application;

Figure 8 is a cross-sectional view of the vibration damper of Figure 7;

Figure 9 is a cross-sectional view showing a second embodiment of the vibration damper of the present application;

Figure 10 is a cross-sectional view showing a third embodiment of the vibration damper of the present application;

Figure 11 is a cross-sectional view showing a fourth embodiment of the vibration damper of the present application;

12 is a schematic structural view of a pan/tilt head according to the present application;

Figure 13 is a schematic structural view of a drone of the present application;

Figure 14 is a partial enlarged view of the portion A of Figure 13;

Figure 15 is a comparison diagram of the acceleration response of the X-axis;

Figure 16 is a comparison diagram of the acceleration response of the Y-axis;

Figure 17 is a comparison of the acceleration response of the Z-axis.

detailed description

The present application is further described below in conjunction with the accompanying drawings:

Example 1:

7 and 8 are vibration dampers 100 provided in an embodiment of the present application. The damper 100 is hollow, and includes a connecting portion 102 and a buffer portion 101 respectively located at both ends of the connecting portion 102. The size of the cross section of the damper member 100 gradually decreases along the direction from the buffer portion 101 toward the connecting portion 102. . The cross section of the damper member 100 refers to a section perpendicular to the central axis L of the damper member 100. In the present embodiment, the damper member 100 has a circular cross section.

It is to be noted that when the two buffer portions 101 are directly connected, the connecting portion 102 is a portion where the two buffer portions 101 are connected.

In the present embodiment, the buffer portions 101 are symmetrically disposed at both ends of the connecting portion 102, that is, the buffer portions 101 having the same structure and shape are symmetrically disposed at both ends of the connecting portion 102. It can be understood that in other embodiments, the structure and shape of the two buffer portions 101 may also be different. Buffer The portion 101 has a hollow truncated cone shape, and the connecting portion 101 has a hollow cylindrical shape. At least one of the outer surface and the inner surface of the buffer portion 101 is stepped to form a multi-layered stepped structure, that is, the outer diameter of the buffer portion 101 is stepped down in the direction in which the buffer portion 101 is directed toward the connecting portion 102. When subjected to pressure or tension, the buffer portion 101 can be folded along the stepped structure to further buffer and vibration.

In addition, the damping member 100 may also be filled with a damping material, which may be a flexible material such as foam or a damping grease, thereby further improving the vibration damping effect. In this embodiment, the vibration damper 100 can be integrally molded by using a flexible material such as silica gel or rubber.

The shock absorbing member provided in the embodiment of the present application has a smaller size of the buffer portion at the two ends of the connecting portion at the middle portion, and the central portion is reduced in volume, the middle portion is reduced, and the vibration absorbing member is more flexible than the existing structure. At the same time, the natural frequency corresponding to the second-order mode of the vibration-damping member is greatly improved, and the frequency coupling between the vibration-damping member and the fuselage in the high-frequency portion is avoided, so that the vibration of the pan-tilt system in the range of 50 Hz to 300 Hz can be reduced by 50. Above %, the vibration damper can effectively isolate the high-frequency vibration from the fuselage, making the picture taken by the camera on the gimbal clearer.

Example 2:

FIG. 9 is a schematic structural diagram of a vibration damping device 200 according to an embodiment of the present application. The same as Embodiment 1, the vibration damper 200 still includes the connecting portion 202 and the buffer portion 201 respectively located at both ends of the connecting portion 202, and the cross-sectional dimension of the damper member 200 is directed from the buffer portion 201 toward the connecting portion 202. slowing shrieking.

The difference from the previous embodiment is that although the buffer portion 201 is still in the shape of a hollow truncated cone in the present embodiment, there is no stepped structure on the inner and outer surfaces thereof, and the central portion of the buffer portion 201 is a truncated cone-shaped hollow body, buffered. The diameter of the portion 201 gradually decreases toward the connecting portion 202 along the buffer portion 201.

Example 3:

FIG. 10 is a shock absorbing member 300 according to an embodiment of the present invention, including a connecting portion 302 and a buffer portion 301 respectively located at two ends of the connecting portion 302. The cross-sectional dimension of the vibration damping member 300 is directed to the connecting portion 302 along the self-buffering portion 101. The direction is gradually decreasing.

The buffer portion 301 in this embodiment has a hollow hemispherical shape. When the hemispherical structure is subjected to pressure or tension, the position of the fold of each folding deformation is different, and the folding fatigue at the same position can be reduced. To prevent breakage at the crease and prolong the service life of the vibration damper.

Example 4:

11 is a vibration damping member 400 according to an embodiment of the present application, including a connecting portion 402 and a buffer portion 401 respectively located at two ends of the connecting portion 402. The cross-sectional dimension of the vibration damping member 400 is directed to the connecting portion 402 along the self-buffering portion 401. The direction is gradually decreasing.

In the present embodiment, the buffer portion 401 to the connecting portion 402 are smooth transitions, and specifically, the outer contour shape of the vibration damping member 400 is a hyperboloid. Compared with the embodiment 1-3, the damper 400 of the present embodiment has a smooth transition from the buffer portion 402 to the connecting portion 401, and the stress concentration of the connecting portion of the buffer portion 402 to the connecting portion 401 can be avoided when subjected to pressure or tension. The risk of breakage caused by repeated folding or deformation is avoided at this point, and the service life of the vibration damping member 400 is prolonged. At the same time, the outer contour structure of the hyperboloid is more susceptible to torsional deformation when subjected to a torsional force, and the vibration force component along the circumferential direction of the vibration damper 400 can be eliminated, thereby further improving the cushioning and vibration isolation effect.

Example 5:

As shown in FIG. 12 , the embodiment of the present application discloses a pan/tilt head 10 that includes a first connecting plate 11 , a second connecting plate 12 , and is connected between the first connecting plate 11 and the second connecting plate 12 . Damper 100. As an example, the vibration damper 100 shown in FIG. 12 is the vibration damper 100 shown in FIG. It can be understood that the vibration damper of FIGS. 8 to 10 can also be applied to the platform 10.

Example 6

As shown in FIG. 13 and FIG. 14 , the embodiment of the present application further discloses a drone 20 that includes a body 21 and the above-described pan/tilt head 10 connected to the body 21 .

After the frequency response analysis of the gimbal installed with the vibration damper provided in this application, it can be found that Compared with the pan/tilt head on which the existing vibration-damping member is installed, the vibration of the unmanned aerial platform head mounted with the vibration-damping member provided by the present application in the range of 50 Hz to 300 Hz can be reduced by more than 50%, as shown in Figs. Fig. 15 is a comparison diagram of the acceleration response of the X-axis, Fig. 16 is a corresponding comparison diagram of the acceleration of the Y-axis, and Fig. 17 is a corresponding comparison diagram of the acceleration of the Z-axis.

The above is only the preferred embodiment of the present application, and is not intended to limit the scope of the embodiments of the present application. The present application is not limited to the above examples, and equivalent changes and improvements made by those skilled in the art within the scope of the present application are all within the scope of the patent application of the present application.

Claims

A vibration damping member comprising: a connecting portion and a buffer portion respectively located at both ends of the connecting portion, wherein a cross-sectional dimension of the vibration damping member is gradually decreased in a direction from the buffer portion toward the connecting portion small.
The vibration damping member according to claim 1, wherein the buffer portion is symmetrically disposed at both ends of the connecting portion.
The vibration damper according to claim 1 or 2, wherein the buffer portion has a truncated cone shape.
The vibration damping member according to any one of claims 1 to 3, wherein at least one of an outer surface and an inner surface of the buffer portion is stepped.
The vibration damper according to claim 1 or 2, wherein the buffer portion has a hemispherical shape.
The vibration damping member according to claim 1 or 2, wherein the buffer portion smoothly transitions to the connecting portion.
The vibration damper according to claim 6, wherein the outer shape of the vibration damper is a hyperboloid.
The vibration damping member according to any one of claims 1 to 7, wherein the vibration damping member is filled with a damping material.
A pan/tilt head, comprising: a first connecting plate, a second connecting plate and a vibration damping member, wherein the first connecting plate and the second connecting plate are connected by the vibration damping member, the vibration damping member A vibration damper according to any one of claims 1-8.
A drone characterized by comprising a body, and a head according to claim 9 connected to the body.