Patent Publication Number: US-2020290718-A1

Title: Unmanned aerial vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International Application No. PCT/CN2017/115032, filed on Dec. 7, 2017, the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of aircraft technology and, more particularly, to an unmanned aerial vehicle. 
     BACKGROUND 
     Common aircrafts are divided into two categories, rotorcraft and fixed-wing aircraft. Rotorcraft may take off and land vertically at a low speed. It does not require much on airport runways, but has a lower flight speed and a shorter flight distance than a fixed-wing aircraft. Fixed-wing aircraft has high take-off and landing speeds, but has high requirements for airport runways. Each of the two aircraft types has its advantages and disadvantages. An aircraft cannot have both of the above described advantages. 
     SUMMARY 
     In accordance with the present disclosure, there is provided an unmanned aerial vehicle. The unmanned aerial vehicle includes a fuselage, a plurality of rotor propulsion assemblies installed on the fuselage, and a fixed-wing propulsion assembly that is detachably installed on the fuselage. The fixed-wing propulsion assembly is able to rotate relative to the fuselage when the fixed-wing propulsion assembly is installed on the fuselage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic plan view of an unmanned aerial vehicle according to some embodiments of the present disclosure. 
         FIG. 2  is a schematic plan view of another unmanned aerial vehicle according to some embodiments of the present disclosure. 
         FIG. 3  is a schematic plan view of another unmanned aerial vehicle according to some embodiments of the present disclosure. 
         FIGS. 4-6  are schematic plan views of ailerons of an unmanned aerial vehicle in different states according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the present disclosure will be described in detail hereinafter. Examples of the embodiments are illustrated in the drawings, where the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout the drawings. The embodiments described below with reference to the accompanying drawings are merely for exemplary purposes, and are merely used to explain the present disclosure, but should not be construed as limiting the present disclosure. 
     In the description of the present disclosure, it is to be understood that the orientation or positional relationships indicated by the terms such as “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “up”, “down”, “front”, “ rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, or “counterclockwise” are based on the orientation or positional relationship illustrated in the drawings, which are for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, or must be organized and operated in a specific orientation. Therefore, such orientation or positional relationships should not be constructed as a limitation to the present disclosure. In addition, the terms “first” and “second” are used for descriptive purposes only and should not be constructed as indicating or implying relative importance or implicitly indicating the number of specified technical features. Therefore, the features defined as “first” and “second” may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of “a plurality” is at least two, for example, two, three, etc., unless it is specifically defined. 
     In the description of the present disclosure, it should be noted that the terms “installation”, “connection”, and “fixation” and the like should be interpreted in their broadest meanings unless explicitly stated and limited otherwise. For example, a connection may be a fixed connection, a detachable connection, or an integrated connection; or it may be a mechanical connection, an electrical connection, or an inter-communication; or it may be a direct connection or an indirect connection through an intermediate medium; or it may be an internal communication between two elements or an interaction relationship between two elements, etc. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure may be interpreted according to specific applications. 
     In the present disclosure, unless explicitly stated and defined otherwise, the fact that the first feature is “above” or “below” the second feature may include that the first and second features are in direct contact, and may also include that the first and second features are not in direct contact, but rather connected through other features between the two. Moreover, the fact that the first feature is “above”, “over”, and “beyond” the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the first feature is higher in altitude than the second feature. The fact that the first feature is “below”, “under”, and “beneath” the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the first feature is lower in altitude than the second feature. 
     The following description provides many different embodiments or examples for implementing different structures/organizations of the present disclosure. To simplify the description of the present disclosure, the components and settings of specific examples are described below. Apparently, these examples are merely for exemplary purposes and are not intended to limit the present disclosure. In addition, the present disclosure may repeat reference numerals and/or reference letters in different examples, and such repetition is for the sake of simplicity and clarity, but does not indicate the relationship between the various embodiments and/or settings discussed therein. In addition, the present disclosure provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and/or materials applicable in the present disclosure. 
     Referring to  FIG. 1 , an unmanned aerial vehicle (UAV)  100  according to an embodiment of the present disclosure includes a fuselage  10 , a plurality of rotor propulsion assemblies  20  and a fixed-wing propulsion assembly  30 . The plurality of rotor propulsion assemblies  20  are disposed on the fuselage  10 . The fixed-wing propulsion assembly  30  may be detachably installed on the fuselage  10 . When the fixed-wing propulsion assembly  30  is installed on the fuselage  10 , the fixed-wing propulsion assembly  30  may rotate relative to the fuselage  10 . 
     Specifically, the number of fixed-wing propulsion assembly  30  may be two, four, six, or any even number. When the number of the fixed-wing propulsion assemblies  30  is two, the two fixed-wing propulsion assemblies  30  are installed on opposite sides of the fuselage  10 , and the two fixed-wing propulsion assemblies  30  are symmetrically disposed with respect to the fuselage  10 . When the number of the fixed-wing propulsion assemblies  30  is four, two fixed-wing propulsion assemblies  30  are installed on one side of the fuselage  10 , and the other two fixed-wing propulsion assemblies  30  are installed on the other side of the fuselage  10 . The four fixed-wing propulsion assemblies are symmetrically installed with two fixed-wing propulsion assemblies  30  disposed on opposite sides with respect to the fuselage  10 . When the number of the fixed-wing propulsion assemblies  30  is six or any even number, the plurality of fixed-wing propulsion assemblies  30  are also symmetrically disposed on opposite sides of the fuselage  10 . 
     When the UAV  100  needs to fly up and down frequently (e.g., when the UAV  100  is flying in a mountain environment), the fixed-wing propulsion assemblies  30  may be detached from the fuselage  10  to avoid a problem of the reduced endurance of the UAV due to the too-heavy weight of the UAV  100  caused by the fixed-wing propulsion assemblies  30 . 
     If the fixed-wing propulsion assemblies  30  are installed on the fuselage  10 , when the UAV  100  is in a level flight state, the air flowing through the outer surface of the fixed-wing propulsion assemblies  30  causes the fixed-wing propulsion assemblies  30  to generate a upward lift, which reduces the rotation speed of the rotor propulsion assemblies  20  and ensures that the UAV  100  hovers in the air. When the air flowing through the outer surface of the fixed-wing propulsion assemblies  30  causes the lift generated by the fixed-wing propulsion assemblies  30  to be equal to the gravity of the UAV  100 , the rotor propulsion assemblies  20  may even be shut off. 
     If the fixed-wing propulsion assemblies  30  are installed on the fuselage  10 , when the UAV  100  is in a climbing state, the fixed-wing propulsion assemblies  30  may rotate relative to the fuselage  10 . In particular, when the UAV  100  climbs vertically, the fixed-wing propulsion assemblies  30  may rotate around the pitch axis to reduce the magnitude of the wind resistance experienced by the fixed-wing propulsion assemblies  30  when the UAV  100  climbs, thereby reducing the energy loss of the UAV  100 . 
     The fixed-wing propulsion assemblies  30  of the UAV  100  according to the embodiments of the present disclosure may be detachably installed on the fuselage  10 . Accordingly, the UAV  100  may be selected to install the fixed-wing propulsion assemblies  30  on the fuselage  10  or detach the installed fixed-wing propulsion assemblies  30  from the fuselage  10  according to the flight environment. This allows the UAV  100  to have a larger endurance under different flight environments. Meanwhile, when the UAV  100  is in a level flight mode, the lift generated by the fixed-wing propulsion assemblies  30  may lift the UAV  100 , thereby reducing the energy loss of the rotor propulsion assemblies  20 . Furthermore, since the fixed-wing propulsion assemblies  30  may be able to rotate relative to the fuselage  10  when the fixed-wing propulsion assemblies  30  are installed on the fuselage  10 , when the UAV  100  climbs vertically, the fixed-wing propulsion assemblies  30  may rotate around the pitch axis. This reduces the magnitude of the wind resistance experienced by the fixed-wing propulsion assemblies  30  when the UAV  100  climbs, thereby reducing the energy loss of the UAV  100 . 
     Referring to  FIG. 1  and  FIG. 2 , the UAV  100  according to an embodiment of the present disclosure includes a fuselage  10 , a plurality of rotor propulsion assemblies  20  and fixed-wing propulsion assemblies  30 . 
     The fuselage  10  includes a nose  11 , a tail  12 , an abdomen  13 , and a back  14 . The tail  12  and the nose  11  are located on opposite sides of the fuselage  10 . The nose  11  is located at the front side in the forward direction of the UAV  100 , while the tail  12  is located at the rear side in the forward direction of the UAV  100 . The abdomen  13  is located under the fuselage  10 , and the back  14  and the abdomen  13  are located on opposite sides of the fuselage  10 . During the normal flight of the UAV  100 , the abdomen  13  is closer to the ground than the back  14 . A plurality of mounting ends  15  are symmetrically disposed on two sides of the fuselage  10 . 
     Each rotor propulsion assembly  20  includes a connection arm  21  and a rotor blade  22 . One end of the connection arm  21  is fixedly connected to the fuselage  10 , and the other end of the connection arm  21  includes a rotor blade  22  installed therein. The center axis of the rotor blade  22  may be consistent with the up and down moving direction of the UAV  100 . Specifically, the connection arms  21  extend outward from the side surface of the fuselage  10 , and a plurality of connection arms  21  are symmetrically disposed around the center position of the fuselage  10 . When the UAV  100  climbs vertically, the central axis Al of the rotor blade  22  is consistent with the climbing direction of the UAV  100 . 
     The number of the fixed-wing propulsion assemblies  30  is a plurality, and the plurality of fixed-wing propulsion assemblies  30  are symmetrically installed on two sides of the fuselage  10 . A fixed-wing propulsion assembly  30  includes a fixed-wing main body  31  and a driving motor  32 . The fixed-wing main body  31  includes a connection end  312 . The connection end  312  may be detachably mounted on a mounting end  15 , and the connection end  312  may rotate relative to the mounting end  15  after being mounted on the mounting end  15 . The driving motor  32  includes a stator  321  and a rotor  322 . The stator  321  is fixed on the mounting end  15 . The rotor  322  is connected to the connection end  312 . When the driving motor  32  drives the rotor  322  to rotate relative to the stator  321 , the rotor  322  may drive the fixed-wing main body  31  to rotate relative to the fuselage  10 . In the disclosed embodiments, the stator  321  may also be fixed on a connection end  312 , and the rotor  322  is connected to the mounting end  15 . When the driving motor  32  drives the rotor  322  to rotate relative to the stator  321 , the stator  321  may drive the fixed-wing main body  31  to rotate relative to the fuselage  10 . 
     A connection end  312  and a mounting end  15  may be connected together in a snap-fit manner. Specifically, the mounting end  15  includes a first engaging member, the connection end  312  includes a second engaging member. After the engagement through the snap-fit, the connection end  312  and the mounting end  15  may be able to rotate relative to each other. In some embodiments, the mounting end  15  further includes a first limiter, and the connection end  312  further includes a second limiter. The first limiter and the second limiter cooperate with each other to limit the maximum rotation angle between the fuselage  10  and the fixed-wing propulsion assemblies  30 . In some embodiments, the mounting end  15  further includes a first thread, and the connection end  312  further includes a second thread. The first thread and the second thread are screwed to each other to connect the connection end  312  with the mounting end  15 . 
     When the UAV  100  needs to fly up and down frequently (e.g., when the UAV  100  is flying in a mountain environment), the fixed-wing propulsion assemblies  30  may be detached from the fuselage  10  to avoid a problem of the reduced endurance of the UAV due to the too-heavy weight of the UAV  100  caused by the fixed-wing propulsion assemblies  30 . 
     If the fixed-wing propulsion assemblies  30  are installed on the fuselage  10 , when the UAV  100  is in a level flight state, the air flowing through the outer surface of the fixed-wing propulsion assemblies  30  causes the fixed-wing propulsion assemblies  30  to generate a upward lift, which then reduces the rotation speed of the rotor propulsion assemblies  20  and ensures that the UAV  100  may hover in the air. When the air flowing through the outer surface of the fixed-wing propulsion assemblies  30  causes the lift generated by the fixed-wing propulsion assemblies  30  to be equal to the gravity of the UAV  100 , the rotor propulsion assemblies  20  may also be shut off. 
     If the fixed-wing propulsion assemblies  30  are installed on the fuselage  10 , when the UAV  100  is in a climbing state, the fixed-wing propulsion assemblies  30  may rotate relative to the fuselage  10 . In particular, when the UAV  100  climbs vertically, the fixed-wing propulsion assemblies  30  may rotate around the pitch axis to reduce the magnitude of the wind resistance experienced by the fixed-wing propulsion assemblies  30  when the UAV  100  climbs, thereby reducing the energy loss of the UAV  100 . 
     The fixed-wing propulsion assemblies  30  of the UAV  100  according to the embodiments of the present disclosure may be detachably installed on the fuselage  10 . Accordingly, based on the flight environment, the UAV  100  may be selected to install the fixed-wing propulsion assemblies  30  on the fuselage  10 , or detach the installed fixed-wing propulsion assemblies  30  from the fuselage  10 , which then allows the UAV  100  to have a larger endurance under different flight environments. Meanwhile, when the UAV  100  is in a level flight mode, the lift generated by the fixed-wing propulsion assemblies  30  may lift the UAV  100 , thereby reducing the energy loss of the rotor propulsion assemblies  20 . Furthermore, since the fixed-wing propulsion assemblies  30  may be able to rotate relative to the fuselage  10  when the fixed-wing propulsion assemblies  30  are installed on the fuselage  10 , when the UAV  100  climbs vertically, the fixed-wing propulsion assemblies  30  may rotate around the pitch axis. This reduces the magnitude of the wind resistance experienced by the fixed-wing propulsion assemblies  30  when the UAV  100  climbs, thereby reducing the energy loss of the UAV  100 . 
     Referring to  FIG. 1 , in some embodiments, in the nose  11  to tail  12  direction of the fuselage  10 , that is, in the roll axis direction of the UAV  100 , the plurality of rotor propulsion assemblies  20  are disposed alternatively and spaced apart from the fixed-wing propulsion assemblies  30 . 
     Specifically, the number of the fixed-wing propulsion assemblies  30  may be one or more. When the rotor blades  22  rotate, the airflow generated by the rotor blades  22  may interfere with the fixed-wing main body  31  and cause the flight of the UAV  100  to be unstable. In the disclosed embodiments, the plurality of rotor propulsion assemblies  20  and the fixed-wing propulsion assemblies  30  are alternatively disposed and spaced apart from each other, thereby preventing the airflow generated by the rotor propulsion assemblies  20  from interfering with the fixed-wing propulsion assemblies  30 , thereby making the flight of the UAV  100  more stable. 
     Referring to  FIG. 1 , in some embodiments, in the nose  11  to tail  12  direction of the fuselage  10 , that is, in the roll axis direction of the UAV  100 , the plurality of rotor propulsion assemblies  20  are alternatively disposed and spaced apart from the wing propulsion assemblies  30 . The plurality of rotor propulsion assemblies  20  are symmetrically distributed around the center of the fuselage  10 . The plurality of rotor propulsion assemblies  20  are disposed on two sides of the fixed-wing propulsion assemblies  30  near the nose  11  and the tail  12 . 
     Specifically, the fixed-wing propulsion assemblies  30  are installed at a position closer to the center of the fuselage  10 , where the center of the fuselage  10  may be the center of gravity of the fuselage  10 . By disposing the fixed-wing propulsion assemblies  30  closer to the center of the fuselage  10 , the UAV  100  does not generate a forward bending moment or a backward bending moment under the action of the fixed-wing propulsion assemblies  30 , thereby balancing the UAV  100  after the fixed-wing propulsion assemblies  30  are installed on the fuselage  10 . The plurality of rotor propulsion assemblies  20  are symmetrically distributed around the center of the fuselage  10 , which is convenient for controlling the plurality of rotor propulsion assemblies  20  to coordinately act to control the UAV  100  to complete various flight modes (e.g., climb mode, dive mode, forward flight mode, rear flight mode, side flight mode). 
     Referring to  FIG. 1  and  FIG. 2 , in some embodiments, the plurality of rotor propulsion assemblies  20  are disposed above the fixed-wing propulsion assemblies  30  in an abdomen  13  to back  14  direction of the fuselage  10  (as shown in  FIG. 2 ). Optionally, the plurality of rotor propulsion assemblies  20  are disposed obliquely above (not directly above) the fixed-wing propulsion assemblies  30 . That is, in the roll axis direction of the UAV  100 , the plurality of rotor propulsion assemblies  20  and the fixed-wing propulsion assemblies  30  are spaced apart and the plurality of rotor propulsion assemblies  20  are disposed above the fixed-wing propulsion assemblies  30 . In some embodiments, the plurality of rotor propulsion assemblies  20  may also be disposed below the fixed-wing propulsion assemblies  30  (as shown in  FIG. 3 ). Optionally, the plurality of rotor propulsion assemblies  20  are disposed obliquely below (not directly below) the fixed-wing propulsion assemblies  30 . That is, in the roll axis direction of the UAV  100 , the plurality of rotor propulsion assemblies  20  are spaced apart from the fixed-wing propulsion assemblies  30  and the plurality of rotor propulsion assemblies  20  are disposed under the fixed-wing propulsion assemblies  30 . Alternatively, some of the rotor propulsion assemblies are disposed below the fixed-wing propulsion assemblies  30 , while the remaining of the rotor propulsion assemblies  20  are disposed above the fixed-wing propulsion assemblies  30 . 
     Referring to  FIG. 1 , in some embodiments, the UAV  100  further includes a propeller propulsion assembly  40 . The propeller propulsion assembly  40  is installed on the tail  12  of the fuselage  10 . By installing the propeller propulsion assembly  40  on the tail  12 , it may be used to propel the UAV  100  forward. 
     When the UAV  100  is in the climbing, diving, or hovering state, the rotor propulsion assemblies  20  are turned on, which provides the lift for the UAV  100 . At this moment, the propeller propulsion assembly  40  is turned off. When the UAV  100  is in a flying forward state, the propeller propulsion assembly  40  is turned on, which provides the forward propulsion for the UAV  100 . The rotational speed of the rotor propulsion assemblies  20  in the flying forward state is lower than that in the hovering state. At this moment, the lift of the UAV  100  is provided by the rotor propulsion assemblies  20  and the fixed-wing propulsion assemblies  30  together. Alternatively, the rotor propulsion assemblies  20  may be turned off, and the lift of the UAV  100  is provided by the fixed-wing propulsion assemblies  30 . In some embodiments, the propeller propulsion assembly  40  may be installed on the nose  11  of the fuselage  10 . By installing the propeller propulsion assembly  40  on the nose  11 , it may be used to pull the UAV  100  forward. Alternatively, the number of the propeller propulsion assemblies  40  is two, and the two propeller propulsion assemblies  40  are installed on the nose  11  and the tail  12 , respectively. 
     Referring to  FIG. 1 , in some embodiments, the UAV  100  further includes a propeller propulsion assembly  40 , and the propeller propulsion assembly  40  is installed on the nose  11  or the tail  12  of the fuselage  10 . The propeller propulsion assembly  40  includes a propeller  41 , and the centerline axis A 2  of the propeller  41  is consistent with the forward direction of the UAV  100 . When the propeller propulsion assembly  40  is installed on the tail  12 , it facilitates the propeller propulsion assembly  40  to push the UAV  100  forward. When the propeller propulsion assembly  40  is installed on the nose  11 , it facilitates the propeller propulsion assembly  40  to pull the UAV  100  forward. 
     Referring to  FIG. 1 , in some embodiments, a fixed-wing propulsion assembly  30  includes a fixed-wing main body  31  and an aileron  33  disposed on the fixed-wing main body  31 . The aileron  33  is disposed on the side of the fixed-wing main body  31  near the tail  12 . Specifically, each fixed-wing propulsion assembly  30  includes at least one aileron  33 . When the number of the fixed-wing propulsion assemblies  30  is a plurality and the plurality of fixed-wing propulsion assemblies  30  are symmetrically disposed on two sides of the fuselage  10 , a plurality of ailerons  33  of the plurality of fixed-wing propulsion assemblies  30  are also disposed symmetrically with respect to the fuselage  10 . 
     Referring to  FIG. 4 , when the UAV  100  is flying forward, if the plurality of ailerons  33  are turned toward the back  14  side of the fuselage  10 , the air velocity will increase and the air pressure will decrease on the side of the fixed-wing main body  31  corresponding to the back  14 . This then increases the lift generated by the fixed-wing main body  31 , so that the UAV  100  may climb without increasing the rotation speed of the rotor propulsion assemblies  20 , thereby reducing the energy loss of the UAV  100 . 
     Referring to  FIG. 5 , when the UAV  100  is flying forward, if the plurality of ailerons  33  are turned toward the abdomen  13  side of the fuselage  10 , the air velocity will increase and the air pressure will decrease on the side of the fixed-wing main body  31  corresponding to the abdomen  13 . This reduces the lift generated by the fixed-wing main body  31 , thereby lowering the altitude of the UAV  100 . 
     Referring to  FIG. 6 , when the UAV  100  is flying forward, if the aileron  33  on one side of the fuselage  10  is turned toward the back  14  side of the fuselage  10 , and the aileron  33  on the other side of the fuselage  10  is turned toward the abdomen  13  side of the fuselage  10 , the lift generated by the aileron  33  turned toward the back  14  side is larger than the lift generated by the aileron  33  turned toward the abdomen  13  side, which then allows the UAV  100  to flip toward one side of the fuselage  10 . 
     In the description of this specification, the descriptions for the reference terms “certain embodiments”, “one embodiment”, “some embodiments”, “exemplary embodiments”, “examples”, “specific examples”, or “some examples”, etc., mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the described specific features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples. 
     Although the embodiments of the present disclosure have been illustrated and described above, it is to be understood that the above embodiments are merely for exemplary purposes and should not be construed as limiting the present disclosure. Those skilled in the art may change, modify, replace, or alter the above embodiments within the scope of the present disclosure, which is defined by the appended claims and their equivalents.