Unmanned aerial vehicle and control method

Abstract

The invention relates to the technical field of unmanned aerial vehicles, and discloses an unmanned aerial vehicle and a control method. The unmanned aerial vehicle comprises a fuselage, a transmission mechanism and an undercarriage. The undercarriage comprises at least two connecting rods, each connecting rod comprises a first arm section and a second arm section which are rotationally connected, the first arm sections can rotate around a first axis, the second arm sections can rotate around a second axis, the transmission mechanism can drive all the first arm sections to be close to or away from each other, so that all the connecting rods can be located at the first position, and the connecting rods jointly form a spherical parallel mechanism. The undercarriage is arranged to be of a multi-connecting-rod structure, a transmission structure can drive all connecting rods to move so that the undercarriage can adapt to landing positions of different sizes, and the undercarriage can also adapt to uneven landing positions through the rotatable first arm section and the rotatable second arm section. When the spherical parallel mechanism is formed, the rotation center of the unmanned aerial vehicle is fixed to be the sphere center in the leveling process, the control algorithm and trajectory planning are greatly simplified, and the leveling function is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicles, in particular to an unmanned aerial vehicle and a control method. BACKGROUND

[0002] The unmanned aerial vehicle is currently applied in many fields, so the unmanned aerial vehicle also needs to meet the landing demand of complex terrain in different fields. After the unmanned aerial vehicle lands on the complex terrain, the fuselage also needs to be leveled to enable the fuselage to be placed stably and facilitate the subsequent take-off process. The unmanned aerial vehicle in the prior art has insufficient comprehensive performance in landing on complex terrain and leveling. SUMMARY

[0003] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes an unmanned aerial vehicle which can adapt to landing on complex terrain and has a leveling function for the fuselage.

[0004] The present application also proposes a control method for controlling the above unmanned aerial vehicle.

[0005] The unmanned aerial vehicle according to the first aspect of the present application comprises a fuselage, a transmission mechanism and a landing gear. The transmission mechanism is arranged below the fuselage. The landing gear is connected to the fuselage through the transmission mechanism, and the landing gear comprises at least two connecting rods. The connecting rod comprises a first arm segment and a second arm segment which are rotatably connected. One end of the first arm segment away from the second arm segment is connected to the transmission mechanism. One end of the second arm segment away from the first arm segment is a landing end which is used to contact a landing place. The first arm segment can rotate relative to the transmission mechanism about a first axis. The second arm segment can rotate relative to the first arm segment about a second axis. The transmission mechanism can drive all the first arm segments to move close to or away from each other, so that all the connecting rods can be in a first position. When the connecting rods are in the first position, all the first axes and the second axes intersect at the same point. The connecting rods collectively form a spherical parallel mechanism.

[0006] The unmanned aerial vehicle according to the present application has at least the following beneficial effects: by setting the landing gear into a multi-connecting rod structure and the transmission mechanism can drive all the connecting rods to move, so as to adapt to landing places of different sizes, ensure that all the connecting rods can land on the landing place so that the unmanned aerial vehicle can land, and the rotatable first arm segment and the second arm segment also enable the landing gear to adapt to uneven landing places. When all the connecting rods are in the first position, the connecting rods collectively form a spherical parallel mechanism. In the spherical parallel mechanism, the center of rotation does not change with the change of the attitude during the leveling process, which greatly simplifies the control algorithm and the trajectory planning, and further improves the leveling function.

[0007] According to some embodiments of the present application, the fuselage comprises six flight arms which are symmetrically arranged around a central axis of the UAV, and the landing gear comprises three connecting rods, each of which is arranged below any three flight arms, and each connecting rod is slidable along the length of the flight arms.

[0008] According to some embodiments of the present application, the angle between any two connecting rods is equal, or the angle between any two connecting rods is smaller than the angle between any two connecting rods and the third connecting rod.

[0009] According to some embodiments of the present application, the transmission mechanism comprises a driving bevel gear, a driven bevel gear and guide rods, the driving bevel gear is arranged below the fuselage and has a rotation axis coaxial with the central axis of the fuselage, the driven bevel gear is engaged with the driving bevel gear, the guide rods are connected with the driven bevel gear and have rotation axes coaxial with the driven bevel gear, the guide rods are arranged below any flight arms, each connecting rod is slidably connected with a guide rod and a flight arm, and the driving bevel gear can drive the driven bevel gear to rotate the guide rods so as to move the connecting rods closer to or farther away from the driving bevel gear.

[0010] According to some embodiments of the present application, the first arm segment comprises a first circular arc segment between its two ends, the second arm segment comprises a second circular arc segment between its two ends, the first circular arc segment and the second circular arc segment are circular arc-shaped and have a common center, and in the same connecting rod, the first axis and the second axis intersect at the center of the first circular arc segment and the second circular arc segment.

[0011] According to some embodiments of the present application, the second arm segment can be rotated upward relative to the first arm segment to coincide in the axial direction of the second axis, and the second axis of each connecting rod is located in the same plane.

[0012] According to some embodiments of the present application, the UAV comprises a pressure sensor connected to the landing end, and the pressure sensor is used to detect the pressure received by the landing end.

[0013] According to some embodiments of the present application, the UAV comprises a camera module arranged below the fuselage and an attitude sensor arranged above the fuselage, the camera module is used to detect the terrain of the landing site, and the attitude sensor is used to detect the angle of the fuselage relative to the horizontal plane.

[0014] The control method of the unmanned aerial vehicle according to the second aspect of the embodiment of the present application is used for controlling the unmanned aerial vehicle according to any one of the first aspect of the embodiment of the present application, and the control method comprises the following steps: controlling the transmission mechanism to drive all the connecting rods to move to a preset position. It is observed whether the landing place is horizontal, and when the landing place is not horizontal, the second arm segment is driven to rotate relative to the first arm segment to make the landing end face the landing place. The unmanned aerial vehicle is driven to land until all the landing ends contact the landing place, and the first arm segment and the second arm segment are driven to rotate to make the fuselage parallel to the horizontal plane.

[0015] The control method according to the embodiment of the present application has at least the following beneficial effects: by setting the landing gear into a multi-connecting rod structure, and the transmission structure can drive all the connecting rods to move, so as to adapt to different sizes of the landing place, ensure that all the connecting rods can fall to the landing place, so that the unmanned aerial vehicle can land, and the rotatable first arm segment and the second arm segment also make the landing gear adapt to the uneven landing place. When all the connecting rods are in the first position, the connecting rods collectively form a spherical parallel mechanism, and in the leveling process of the unmanned aerial vehicle, the rotation center does not change with the attitude, greatly simplifying the control algorithm and trajectory planning, and further improving the leveling function.

[0016] According to some embodiments of the present application, the step of controlling the transmission mechanism to drive all the connecting rods to move to a preset position further comprises: observing the area size of the landing place, and when the diameter of the inscribed circle of the landing place is greater than the diameter of the spherical parallel mechanism, driving the connecting rods to move so that all the first axes and the second axes intersect at the same point, so that the connecting rods collectively form a spherical parallel mechanism.

[0017] Additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be further described below in combination with the drawings and embodiments, wherein: Figure 1 It is a perspective view of the unmanned aerial vehicle in the first embodiment of the present application; Figure 2 It is a front view of the unmanned aerial vehicle in the first embodiment of the present application; Figure 3 It is a bottom view of the unmanned aerial vehicle in the first embodiment of the present application; Figure 4 It is a perspective view of the unmanned aerial vehicle in the second embodiment of the present application; Figure 5 It is a perspective view of the unmanned aerial vehicle in the third embodiment of the present application; Figure 6A front view of the unmanned aerial vehicle in the third embodiment of the present application.

[0019] Reference signs: unmanned aerial vehicle 100, fuselage 101, transmission mechanism 102, landing gear 103, connecting rod 104, first arm segment 105, second arm segment 106, flight arm 107, landing end 108, pressure sensor 109, attitude sensor 110, first axis 111, second axis 112, driving bevel gear 201, driven bevel gear 202, guide rod 203, first circular arc segment 204, second circular arc segment 205, camera module 301. DETAILED DESCRIPTION

[0020] Embodiments of the present application are described in detail below with reference to the accompanying drawings, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and cannot be understood as a limitation of the present application.

[0021] In the description of the present application, it is understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0022] In the description of the present application, if the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. is understood as not including the number, above, below, etc. is understood as including the number. If it is described as first, second, it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features.

[0023] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0024] In the description of the application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application. In the description, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0025] With reference to Figure 1 , Figure 2 and Figure 4 , the unmanned aerial vehicle 100 according to the first embodiment of the application comprises a fuselage 101, a transmission mechanism 102 and a landing gear 103. The transmission mechanism 102 is arranged below the fuselage 101. The landing gear 103 is connected to the fuselage 101 through the transmission mechanism 102, and the landing gear 103 comprises at least two connecting rods 104, each connecting rod 104 comprising a first arm segment 105 and a second arm segment 106 connected rotatably, the first arm segment 105 being connected to the transmission mechanism 102 at an end thereof away from the second arm segment 106, and the second arm segment 106 having a landing end 108 at an end thereof away from the first arm segment 105, the landing end 108 being used to contact a landing site, the first arm segment 105 being rotatable relative to the transmission mechanism 102 about a first axis 111, the second arm segment 106 being rotatable relative to the first arm segment 105 about a second axis 112, and the transmission mechanism 102 being capable of driving all the first arm segments 105 to move closer to or away from the transmission mechanism 102, so that all the connecting rods 104 can be in a first position, when the connecting rods 104 are in the first position, all the first axes 111 and the second axes 112 intersect at the same point, and the connecting rods 104 collectively form a spherical parallel mechanism. When the spherical parallel mechanism is formed, the movement trajectories of all the first arm segments 105 and the second arm segments 106 are located on a concentric spherical surface with the intersection point as the spherical center, so that the landing end 108 and the fuselage 101 remain on the concentric spherical surface during adjustment, and the rotation center of the leveling process of the fuselage 101 is the spherical center of the spherical parallel mechanism. By arranging the landing gear 103 in the form of multiple connecting rods 104, and by enabling the transmission mechanism to drive all the connecting rods 104 to move, the landing gear 103 can adapt to landing sites of different sizes, and ensure that all the connecting rods 104 can land on the landing site, so that the unmanned aerial vehicle 100 can land, and the rotatable first arm segments 105 and the second arm segments 106 also enable the landing gear 103 to adapt to uneven landing sites. When all the connecting rods 104 are in the first position, the connecting rods 104 collectively form a spherical parallel mechanism, and the rotation center of the unmanned aerial vehicle 100 during the leveling process (mainly referring to the fuselage 101, the landing gear 103 of the unmanned aerial vehicle 100 moves for the leveling of the fuselage 101) is the spherical center of the spherical parallel mechanism, which does not change with the attitude, greatly simplifying the control algorithm and trajectory planning, and further improving the leveling function.

[0026] It should be noted that, Figure 1 The state shown is the state of the unmanned aerial vehicle 100 when the connecting rod 104 is in the first position, at this time as can be seen from the figure, all the first axis 111 and the second axis 112 intersect at the same point, and Figure 4 The state shown is a state of the unmanned aerial vehicle 100 when the connecting rod 104 is not in the first position, at this time the first axis 111 and the second axis 112 on the same connecting rod 104 intersect at the same point, but the intersection points of different connecting rods 104 do not coincide, Figure 4 The state shown can adapt to a larger landing place, so that the area supported by the three landing ends 108 after landing is larger, and the landing is more stable, and Figure 4 The state shown can still make the fuselage 101 parallel to the horizontal plane after the unmanned aerial vehicle 100 lands by controlling the rotation of each first arm segment 105 and second arm segment 106.

[0027] Reference Figure 3 In some embodiments of the present application, the fuselage 101 includes six flight arms 107 which are axisymmetric around the central axis of the unmanned aerial vehicle 100, and the landing gear 103 includes three connecting rods 104, which are respectively arranged below any three flight arms 107, and the connecting rod 104 can slide along the length direction of the flight arm 107. The axisymmetric design of the six flight arms 107 can make the lift and torque generated by each rotor cancel each other out, reduce the risk of tilting of the fuselage 101, and improve the stability during flight. The operation process involved in flight control can also be simplified, the algorithm efficiency is improved, and further, the camera module 301, attitude sensor and the like can be arranged at the common connection of the roots of all flight arms 107, to ensure that the center of gravity coincides with the center of lift generated during flight of the unmanned aerial vehicle 100. The three connecting rods 104 are arranged to form a more stable structure, the three landing ends 108 can adapt to more common landing places, and the three connecting rods 104 make the landing gear 103 have more degrees of freedom, so that the unmanned aerial vehicle 100 can be better leveled after landing, the connecting rod 104 arranged below the flight arm 107 can also reduce the influence of the connecting rod 104 on the flight process of the unmanned aerial vehicle 100, prevent the swinging of the connecting rod 104 from interfering with the multiple flight arms 107, and also improve the aesthetics of the unmanned aerial vehicle 100.

[0028] Reference Figure 3 In some embodiments of the present application, the included angle between any two connecting rods 104 is equal, or the included angle between two of the connecting rods 104 is smaller than the included angle between each of the two connecting rods 104 and the other connecting rod 104. Since the six flight arms 107 are axisymmetric, the included angle between two adjacent flight arms 107 is equal, Figure 3The shown is the case that the included angle between any two connecting rods 104 is equal, the six flight arms 107 are numbered 1 to 6 in turn, the connecting rod 104 is connected to the first, third and fifth flight arms 107 at this time, the three connecting rods 104 are also axisymmetric, which can make the whole unmanned aerial vehicle 100 better symmetry, the flight process is more stable, and after landing, it is also more stable. The case that the included angle between the two connecting rods 104 is less than the included angle between the other connecting rod 104 is that the two connecting rods 104 are connected to the adjacent flight arms 107, and are spaced apart from the other connecting rod 104 by at least one flight arm 107, specifically, the connecting rod 104 is connected to the first, second and fourth flight arms 107, or the first, second and fifth flight arms 107. The landing end 108 of the three connecting rods 104 designed in this way is asymmetrically arranged relative to the central axis of the unmanned aerial vehicle 100, two of the landing ends 108 are close to each other, and the other landing end 108 is far away. This can adapt to some special terrain, for example, the landing place is relatively narrow, then this design can make the three landing ends 108 all land on the landing place, and this design can still make the three connecting rods 104 form a spherical parallel mechanism at the first position, without affecting the leveling of the unmanned aerial vehicle 100 after landing.

[0029] Reference Figures 1 to 3 In some embodiments of the application, the transmission mechanism 102 includes a driving bevel gear 201, a driven bevel gear 202 and a guide rod 203. The driving bevel gear 201 is arranged below the fuselage 101 and the rotation axis is coaxial with the central axis of the fuselage 101. The driven bevel gear 202 is engaged with the driving bevel gear 201. The guide rod 203 is connected with the driven bevel gear 202 and coaxial with the rotation axis thereof. The guide rod 203 is arranged below any flight arm 107. Each connecting rod 104 is slidably connected with a guide rod 203 and a flight arm 107. The driving bevel gear 201 can drive the driven bevel gear 202 to rotate the guide rod 203, so that the connecting rod 104 approaches or moves away from the driving bevel gear 201. The bevel gear transmission has high transmission efficiency, and the intersection axis design of the driving bevel gear 201 and the driven bevel gear 202 realizes power steering, which transmits the power of the driving bevel gear 201 rotating around the vertical axis to the driven bevel gear 202 in the horizontal direction, optimizes the space design, and as Figure 3The one driving bevel gear 201 can drive multiple driven bevel gears 202, which improves the driving efficiency and the movement consistency of each driven bevel gear 202, ensures that each first arm segment 105 can move synchronously relative to the axis of the driving bevel gear 201, and better enters and leaves the first position. When the driven bevel gear 202 drives the guide rod 203 to rotate, because the guide rod 203 and the flight arms 107 above it are distributed at intervals, the rotation of the first arm segment 105 is limited, so that the first arm segment 105 can only drive the second arm segment 106 to slide along the axis of the guide rod 203.

[0030] Reference Figure 2 In some embodiments of the application, the first arm segment 105 includes a first circular arc segment 204 between the two ends, the second arm segment 106 includes a second circular arc segment 205 between the two ends, the first circular arc segment 204 and the second circular arc segment 205 are circular arc-shaped and have the same center, and the first axis 111 and the second axis 112 intersect at the center of the first circular arc segment 204 and the second circular arc segment 205 in the same connecting rod 104. The centers of the first circular arc segment 204 and the second circular arc segment 205 and the first axis 111 and the second axis 112 coincide, which can make the connecting rod 104 more easily reach Figure 1 the first position shown, thereby forming a spherical parallel mechanism, and such design can also reduce the complexity of the calculation required in the leveling process after the UAV 100 lands. The arc-shaped connecting rod 104 can also reduce the jamming when it rotates in the spherical space, ensure the continuity and stability of the movement, and the equal curvature of the first circular arc segment 204 and the second circular arc segment 205 also facilitates the storage of the connecting rod 104 during flight of the UAV 100, for example, the second circular arc segment 205 can be first rotated upward to Figure 5 the state shown, and then the first circular arc segment 204 is also rotated upward, so that the connecting rod 104 is folded and stored below the fuselage 101, so that the structure of the UAV 100 is more concentrated, and the flight is more stable. It should be noted that in some embodiments of the application, the first arm segment 105 and the second arm segment 106 can have various shapes, such as straight lines or broken lines or irregular arcs, because there are various ways to realize the spherical parallel mechanism, and the arc-shaped connecting rod 104 in this application is improved to improve the stability during rotation and adjustment of the connecting rod 104, and facilitate storage.

[0031] Reference Figure 5 and Figure 6In some embodiments of the invention, the second arm segment 106 can rotate upward relative to the first arm segment 105 to coincide axially with the second axis 112, with the second axis 112 of each link 104 located in the same plane. This design allows for easier landing when the landing point is... Figure 6 When the plane is horizontal, since the second axis 112 is located on the same plane, the connection between the first arm segment 105 and the second arm segment 106 can be used as the contact point with the landing point. The landing gear 103 does not need to be fully extended, which can also reduce the overall center of gravity height of the drone 100 after landing, improve the stability of the drone 100 after landing, and eliminate the need to rotate the first arm segment 105 and the second arm segment 106 to level the fuselage 101, thus reducing computing power consumption.

[0032] refer to Figure 1 In some embodiments of the present invention, the drone 100 includes a pressure sensor 109 connected to the landing end 108. The pressure sensor 109 is used to detect the pressure on the landing end 108. The design of the pressure sensor 109 allows the drone 100 to sense whether the landing ends 108 of each link 104 are in contact with the landing point during the landing process. When all pressure sensors 109 detect a certain level of pressure and the pressure no longer fluctuates significantly, the main control system of the drone 100 can determine that the drone 100 has landed completely. Therefore, the subsequent leveling process of the drone 100 can be performed, improving the smoothness of the overall process and preventing the link 104 from being rotated before a stable landing.

[0033] refer to Figures 1 to 3 In some embodiments of the present invention, the drone 100 includes a camera module 301 and an attitude sensor 110. The camera module 301 is disposed below the fuselage 101, and the attitude sensor 110 is disposed above the fuselage 101. The camera module 301 is used to detect the terrain at the landing site, and the attitude sensor 110 is used to detect the angle of the fuselage 101 relative to the horizontal plane. The attitude sensor 110 measures parameters such as linear acceleration and angular velocity of the UAV 100 during flight using components such as a three-axis accelerometer and a three-axis gyroscope. This allows the sensor to calculate the pitch angle of the UAV 100 and provide timely feedback, improving the stability of the UAV 100 during flight. The attitude sensor 110 can also sense the attitude of the UAV 100 after landing. The camera module 301 can conduct terrain surveys before the UAV 100 lands, creating a three-dimensional terrain model of the landing site and sending it to the main control system of the UAV 100. The camera module 301 determines the size and terrain of the landing site before landing to better determine the approximate landing plan. The attitude sensor 110 can confirm the attitude of the UAV 100 after landing and after the UAV 100 is leveled, improving the stability of the landing process and after landing.

[0034] According to the control method of the unmanned aerial vehicle 100 of the second aspect of the embodiment of the present application, the control method is used to control the unmanned aerial vehicle 100 of any one of the first aspect of the embodiment, and the control method comprises the following steps: controlling the transmission mechanism 102 to drive all the connecting rods 104 to move to a preset position. It is observed whether the landing place is horizontal, and when the landing place is not horizontal, the second arm segment 106 is driven to rotate relative to the first arm segment 105 to make the landing end 108 face the landing place. The unmanned aerial vehicle 100 is driven to land until all the landing ends 108 contact the landing place, and the first arm segment 105 and the second arm segment 106 are driven to rotate to make the fuselage 101 parallel to the horizontal plane. By setting the landing gear 103 into the multi-connecting rod 104 structure, and the transmission structure can drive all the connecting rods 104 to move, so as to adapt to different sizes of the landing place, it is ensured that all the connecting rods 104 can land on the landing place so that the unmanned aerial vehicle 100 can land, and the rotatable first arm segment 105 and the second arm segment 106 also make the landing gear 103 be able to adapt to the uneven landing place. When all the connecting rods 104 are in the first position, the connecting rods 104 collectively form a spherical parallel mechanism, and when the spherical parallel mechanism, the rotation center of the unmanned aerial vehicle 100 does not change with the attitude change in the leveling process, which greatly simplifies the control algorithm and the trajectory planning, and further improves the leveling function.

[0035] In some embodiments of the present application, the step of controlling the transmission mechanism 102 to drive all the connecting rods 104 to move to a preset position further comprises: observing the area size of the landing place, and when the diameter of the inscribed circle of the landing place is greater than the diameter of the spherical parallel mechanism, driving the connecting rods 104 to move so that all the first axes 111 and the second axes 112 intersect at the same point to make the connecting rods 104 collectively form a spherical parallel mechanism. The control algorithm of the spherical parallel mechanism is more concise, and the leveling process is also more stable, so that the connecting rods 104 in the first position can be preferentially considered to use the attitude landing adjustment of the spherical parallel mechanism, and in some embodiments, the connecting rods 104 can also be adjusted to a larger or smaller range of attitude according to the requirements to adapt to different sizes of the landing place.

[0036] The embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge range of ordinary skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An unmanned aerial vehicle (UAV), characterized in that, include: body; A transmission mechanism is provided below the body; The landing gear is connected to the fuselage via the transmission mechanism. The landing gear includes at least two links, each link comprising a first arm segment and a second arm segment rotatably connected. The end of the first arm segment away from the second arm segment is connected to the transmission mechanism, and the end of the second arm segment away from the first arm segment is the landing end, which is used to contact the landing point. The first arm segment can rotate relative to the transmission mechanism about a first axis, and the second arm segment can rotate relative to the first arm segment about a second axis. The transmission mechanism can drive all the first arm segments to move closer or further away, so that all the links can be in a first position. When the links are in the first position, all the first axes and the second axes intersect at the same point, and the links together form a spherical parallel mechanism.

2. The UAV according to claim 1, characterized in that, The fuselage includes six flight arms that are symmetrical about the central axis of the UAV. The landing gear includes three links, which are respectively located below any three flight arms. The links can slide along the length of the flight arms.

3. The UAV according to claim 2, characterized in that, The included angles between any two of the links are equal, or the included angles between two of the links are both smaller than the included angle with the other link.

4. The UAV according to claim 2, characterized in that, The transmission mechanism includes a driving bevel gear, a driven bevel gear, and a guide rod. The driving bevel gear is located below the fuselage and its rotation axis is coaxial with the central axis of the fuselage. The driven bevel gear meshes with the driving bevel gear. The guide rod is connected to the driven bevel gear and is coaxial with its rotation axis. The guide rods are spaced apart below any of the flight arms. Each connecting rod is slidably connected to one guide rod and one flight arm. The driving bevel gear can drive the driven bevel gear to rotate the guide rod, so that the connecting rod moves closer to or away from the driving bevel gear.

5. The UAV according to claim 1, characterized in that, The first arm segment includes a first arc segment between its two ends, and the second arm segment includes a second arc segment between its two ends. The first arc segment and the second arc segment are arc-shaped and their centers coincide. In the same connecting rod, the first axis and the second axis intersect at the centers of the first arc segment and the second arc segment.

6. The UAV according to claim 1, characterized in that, The second arm segment can rotate upward relative to the first arm segment to coincide axially with the second axis, and the second axis of each of the links lies in the same plane.

7. The UAV according to claim 1, characterized in that, The drone includes a pressure sensor connected to the landing end, which is used to detect the pressure applied to the landing end.

8. The UAV according to claim 1, characterized in that, The drone includes a camera module and an attitude sensor. The camera module is located below the fuselage, and the attitude sensor is located above the fuselage. The camera module is used to detect the terrain at the landing site, and the attitude sensor is used to detect the angle of the fuselage relative to the horizontal plane.

9. A method for controlling a drone, used to control the drone according to any one of claims 1 to 8, characterized in that, The control method includes the following steps: Control the transmission mechanism to drive all the connecting rods to a preset position; Observe whether the landing site is level. If the landing site is not level, drive the second arm segment to rotate relative to the first arm segment so that the landing end faces the landing site. Drive the drone to land until all the landing ends contact the landing site; Drive the first arm segment and the second arm segment to rotate so that the fuselage is parallel to the horizontal plane.

10. The control method according to claim 9, characterized in that, The step of controlling the transmission mechanism to drive all the links to a preset position further includes: By observing the area of ​​the landing point, when the diameter of the inscribed circle of the landing point is greater than the diameter of the spherical parallel mechanism, the connecting rod is driven to move so that all the first axes and the second axes intersect at the same point, so that the connecting rods together form a spherical parallel mechanism.

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