Patent Publication Number: US-2020290719-A1

Title: Frame assembly of unmanned aerial vehicle, and unmanned aerial vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/CN2017/099325, filed Aug. 28, 2017, the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to unmanned aerial vehicle stand field and, more particularly, to a frame assembly of an unmanned aerial vehicle (UAV) and an unmanned aerial vehicle (UAV). 
     BACKGROUND 
     An unmanned aerial vehicle (UAV) stand is generally designed as a fixed stand or a foldable stand. The design of the fixed stand is relatively simple as long as the stand can support the body of the UAV. However, while the UAV is in flight, the fixed stand may block a photographing device mounted under the UAV body from photographing normally because the fixed stand is not foldable. The foldable stand not only can support the UAV body, but also turn up in the pitch direction of the UAV to avoid blocking the photographing device mounted under the UAV body while the UAV is in flight. However, the foldable stand is relatively big and not convenient for packaging and transportation. 
     SUMMARY 
     In accordance with the present disclosure, there is provided an unmanned aerial vehicle (UAV) including a power system providing flight power to the UAV and a frame assembly supporting the power system. The frame assembly includes a center frame and an arm assembly. The arm assembly includes an arm connected with the center frame, a deformation rod, and a support rod parallel to the arm. Two ends of the deformation rod are rotatably connected with the arm and the support rod, respectively. The support rod is configured to move translationally relative to the arm while remaining parallel to the arm, so as to be selectively in a folded state or an unfolded state. Each of two ends of the deformation rod forms a first or a second preset angle with one of the arm and the support rod when the support rod is in the folded or unfolded state. The second preset angle is smaller than the first preset angle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a frame assembly according to an embodiment of the disclosure, which reveals the structural relationship of the frame assembly when the support rod is in the unfolded state relative to the arm. 
         FIG. 2  is a perspective view of the frame assembly in another viewing direction according to an embodiment of the disclosure, which reveals the structural relationship of the frame assembly when the support rod is in the unfolded state relative to the arm. 
         FIG. 3  is a perspective view of the frame assembly according to an embodiment of the disclosure, which reveals the structural relationship of the frame assembly when the support rod is in the folded state relative to the arm. 
         FIG. 4  is a perspective view of the frame assembly in another viewing direction according to an embodiment of the disclosure, which reveals the structural relationship of the frame assembly when the support rod is in the folded state relative to the arm. 
     
    
    
     REFERENCE NUMERALS 
     
         
           1 : center frame; 
           2 : arm assembly;  21 : arm;  22 : deformation rod;  23 : support rod; 
           3 : connection rod; 
           4 : gimbal assembly;  41 : gimbal;  42 : photographing device; 
           5 : power system. 
       
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Technical solutions in the embodiments of the present disclosure will be clearly described with reference to the drawings. The described embodiments are only some embodiments not all the embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts are within the scope of the present disclosure. 
     Detailed description is provided for the frame assembly of the UAV of the present disclosure with reference to the drawings. In case of no conflict, the following embodiments and the features of the implementations can be combined with each other. 
     As shown in  FIG. 1 , embodiments of the disclosure provide a UAV frame assembly. The frame assembly includes a center frame  1  and two arm assemblies  2  located respectively on two sides of the center frame  1 . The arm assembly  2  includes an arm  21  connected to the center frame  1 , deformation rods  22 , and a support rod  23 . Two ends of the deformation rods  22  are rotatably connected respectively to the arm  21  and the support rod  23 . For example, a hinged connection, a sleeve ring connection, or another rotational connection may be applied to realize the rotational connection between the deformation rods  22  and arm  21  or between the deformation rods  22  and the support rod  23 . 
     The support rod  23  is parallel to the arm  21 , and the support rod  23  can move while being parallel to the arm  21 , so that the support rod  23  may be selectively in a folded state or an unfolded state. In the present embodiment, the support rod  23  always keeps a parallel relationship with respect to the arm  21  while moving, to reduce the volume of the arm assembly  2 . 
     As shown in  FIG. 2 , while the support rod  23  moves translationally relative to the arm  21  to the unfolded state, the support rod  23  drives the deformation rods  22  to rotate, so that two ends of the deformation rods  22  form first preset angles respectively with the arm  21  and the support rod  23 , and the support rod  23  is used as a stand. In general, the support rod  23  is in the unfolded state when the UAV is landing. The support rod  23  can be used as the stand to support the UAV to ensure that the UAV can land smoothly to the destination. 
     With reference to  FIG. 3  and  FIG. 4 , while the support rod  23  moves translationally relative to the arm  21  to the folded state, the support rod  23  drives the deformation rods  22  to rotate, so that the two ends of the deformation rods  22  form second preset angles respectively with the arm  21  and the support rod  23 . The second preset angles are smaller than the first preset angles. When the UAV is performing a task (aerial photographing) or the UAV is packaged or transported, the support rod  23  is set to the folded state to prevent the support rod  23  and the deformation rods  22  from blocking the photographing device mounted under the UAV during aerial photographing and reduce the volume of the arm assembly  2  for convenient packaging, transportation, and cost reduction. 
     In the embodiments of the present disclosure, with the support rod  23  being set parallel to the arm  21 , and through the movement of the support rod  23  while being parallel to the arm  21  due to the deformation of the deformation rod  22  driven by the support rod  23 , the support rod  23  can switch states between the unfolded state and the folded state. The support rod  23  can support the UAV and also can approach the arm  21  to prevent the support rod  23  from blocking the photographing device mounted under the UAV, and reduce the volume of the frame assembly for convenient UAV packaging or transportation and for the UAV to fly in a tight space. 
     The angle between the deformation rod  22  and the arm  21  and the angle between the deformation rod  22  and the support rod  23  are two alternate interior angles. In the embodiments of the present disclosure, when the support rod  23  moves translationally relative to the arm  21  to the folded state, taking the rotation direction of the deformation rod  22  as reference, the angle between the deformation rod  22  and the arm  21  is the angle formed between the deformation rod  22  and the part of the arm  21  to which the deformation rod  22  approaches in the rotation direction. When the support rod  23  moves translationally relative to the arm  21  to the unfolded state, taking the rotation direction of the deformation rod  22  as reference, the angle between the deformation rod  22  and the arm  21  is the angle formed between the deformation rod  22  and the part of the arm  21  from which the deformation rod  22  moves away in the rotation direction. The angle between the deformation rod  22  and the support rod  23  is the alternate interior angle of the angle between the deformation rod  22  and the arm  21 . 
     The size of the first preset angle and the second preset angle can be selected according to the weight of the center frame  1 , the weight of the gimbal assembly  4  mounted at the center frame  1 , and etc., so that when the deformation rod  22  is at the first preset angle relative to the arm  21 , the support rod  23  can be used as the stand to support the UAV, and when the deformation rod  22  is at the second preset angle relative to the arm  21 , the support rod  23  can approach the arm  21  as close as possible to prevent the support rod  23  from blocking the photographing device mounted under the center frame  1  and reduce the dimensions of the UAV for convenient UAV packaging, transportation and for the UAV to fly in the tight space. In some embodiments, the first preset angle may be larger than or equal to 30° and smaller than or equal to 90°. For example, the first preset angle may be any one of 30°, 40°, 45°, 50°, 60°, 70°, 80°, 90°, or another degree in middle ranges. The second preset angle may be smaller than 20°. For example, the second preset angle may be any one of 0°, 5°, 10°, 15°, or another degree in middle ranges. 
     The first preset angle and the second preset angle can allow a deviation in a certain range, for example, ±0.1%. Taking the first preset angle being 90° as an example for further explanation, the support rod  23  is in the unfolded state when the first preset angle is in the range of 90±0.09°. 
     The frame assembly may also include stoppers (not shown). When the support rod  23  moves translationally relative to the arm  21  to the unfolded state, the stoppers restrict the deformation rods  22  from continuing in the previous rotation direction (i.e., the corresponding direction for the support rod  23  to move translationally relative to the arm  21  to the unfolded state), so that the angle between the deformation rod  22  and the arm  21  does not exceed the maximum value of the first preset angle (e.g., 90°). 
     In some embodiments, when the support rod  23  is in unfolded state, the support rod  23  can be driven continuously to rotate in the previous rotation direction (i.e., the corresponding direction for the support rod  23  to move translationally relative to the arm  21  to the unfolded state) relative to the arm  21  for the support rod  23  to be stably maintained in the unfolded state under the action of the stoppers so as to support the UAV. 
     The method to drive the support rod  23  to move translationally relative to the arm  21  can be selected according to needs to satisfy different requirements. For example, in one embodiment, a manual method is implemented to drive the support rod  23  to move translationally relative to the arm  21 . A user can directly move the support rod  23  translationally to drive the deformation rods  22  to rotate, so that the support rod  23  approaches or moves away from the arm  21 , and correspondingly the support rod  23  moves translationally relative to the arm  21  to the folded state or the unfolded state. 
     In another embodiment, an electrical method is implemented to drive the support rod  23  to move translationally relative to the arm  21 . The frame assembly can also include a driving mechanism (not shown), which drives the deformation rods  22  to rotate or drives the support rod  23  to move translationally relative to the arm  21 , so that the support rod  23  approaches or moves away from the arm  21 , and correspondingly the support rod  23  moves translationally relative to the arm  21  to the folded state or the unfolded state. The driving mechanism can be an electrical motor or another driving mechanism. 
     In the embodiments of the present disclosure, while the support rod  23  approaches or moves away from the arm  21 , the support rod  23  and the arm  21  are always parallel to each other to reduce the volume of the arm assembly  2  and improve the flight safety of the UAV. 
     As shown in  FIG. 1 , in the present embodiment, the arms  21  of the two arm assemblies  2  are set parallel to each other with an interval. The structure is simple, and the frame assembly has a better balance. The arrangement of the arms  21  of the two arm assemblies  2  is not limited, and the arrangement of the arms  21  of the two arm assemblies  2  can be set according to actual situations. 
     The number of the deformation rods  22  can be selected according to the stability requirement of the arm assembly  2 . For example, each arm assembly  2  can include one, two, or more than two deformation rods  22 . For example, each arm assembly  2  has at least two deformation rods  22  to ensure the stability of the arm assembly  2 . In a specific embodiment, each arm assembly  2  has two deformation rods  22 , and the arm  21 , the deformation rods  22 , and the support rod  23  of each arm assembly  2  form a four-link mechanism. The two deformation rods  22  can ensure that the support rod  23  can stably move translationally relative to the arm  21 , and at the same time reduce the weight of the arm assembly  2  as much as possible. 
     The arrangement of the deformation rods  22  can also be set according to the stability requirement of the arm assembly  2 . For example, at least two deformation rods  22  of each arm assembly  2  can be parallel to each other or arranged to cross each other. By setting the deformation rods  22  parallel to each other, the spatial volume of the structure formed by the three parts of the arm  21 , the deformation rods  22 , and the support rod  23  is minimum. The stability of the arm assembly  2  is stronger by cross-arranging the deformation rods  22 . 
     In the embodiments of the present disclosure, two ends of each of at least two deformation rods  22  are rotatably connected respectively to the arm  21  and the support rod  23 , so that the deformation rods  22  can rotate relative to the arm  21  and the support rod  23 , to keep the support rod  23  and the arm  21  parallel to each other. 
     In the following embodiments, the translational movement of the support rod  23  relative to the arm  21  in each arm assembly  2  is further explained with an example in which the at least two deformation rods  22  of each arm assembly  2  are set parallel to each other and the electrical method is implemented to drive the support rod  23  to move translationally relative to the arm  21 . 
     The driving mechanism can drive at least two deformation rods  22  to rotate in the same direction, so that the support rod  23  approaches or moves away from the arm  21 . For example, in one embodiment, the deformation rods  22  are driven by the driving mechanism to rotate in the clockwise direction, so that the support rod  23  moves translationally relative to the arm  21  to the folded state. The deformation rods  22  are driven by the driving mechanism to rotate in the counterclockwise direction, so that the support rod  23  moves translationally relative to the arm  21  to the unfolded state. In another embodiment, the deformation rods  22  are driven by the driving mechanism to rotate in the clockwise direction, so that the support rod  23  moves translationally relative to the arm  21  to the unfolded state. The deformation rods  22  are driven by the driving mechanism to rotate in the counterclockwise direction, so that the support rod  23  moves translationally relative to the arm  21  to the folded state. 
     In other embodiments, the at least two deformation rods  22  can be driven by the driving mechanism to rotate in different directions. For example, one or more of the deformation rods  22  rotate in the clockwise direction, and another one or more of the deformation rods  22  rotate in the counterclockwise direction, so that the deformation rods  22  can switch the states between the folded state and the unfolded state. The present disclosure does not restrict the rotation directions of the deformation rods  22 . 
     With reference to  FIG. 3  and  FIG. 4 , the distance between two adjacent deformation rods  22  is equal to or longer than the length of the deformation rods  22 . When the support rod  23  is in folded state, one side of the deformation rods  22  (non-rotating side) fully fits the arm  21 , and the other side fully fits the support rod  23 , so that the volume of the arm assembly  2  is minimum for the UAV to conveniently perform tasks and for convenient UAV packaging or transportation. In some embodiments, the driving mechanism drives the deformation rod  22  to rotate to the first position (the position for the support rod  23  in the folded state), where the deformation rod  22  are sandwiched between the arm  21  and the support rod  23 , and the two sides of the deformation rod  22  fit the arm  21  and the support rod  23 , respectively, i.e., the angle between the deformation rod  22  and the arm  21  is  0 °, and the angle between the deformation rod  22  and the support rod  23  is  0 °, so that the volume of the frame assembly is minimum. 
     With reference to  FIG. 1 , the frame assembly also includes connection rods  3 , and the arm  21  is fixedly connected to the center frame  1  by the connection rods  3 . The center frame  1  and the connection rods  3  can be set as one-piece, so the structure is simple, and the strength is high. The center frame  1  and the connection rods  3  can also be set separately. For example, the connection rods  3  can be folded to connect to the center frame  1  for convenient folding storage. When the center frame  1  and the connection rod  3  are set separately, in some embodiments, one end of the connection rod  3  is connected to the center frame  1 , and the other end is connected to the arm  21 . In some embodiments, as shown in  FIG. 1 , the center frame  1  is connected to the middle of the connection rod  3 , and the two ends of the connection rod  3  are connected respectively to the arms  21 . 
     The number of the connection rods  3  can be set according to the needs to satisfy the stability requirement of the UAV, for example, two or more than two. In the present embodiment, the connection rods  3  have a number of two and are set parallel to each other with an interval, and the center frame  1  is connected between the two connection rods  3 . 
     When the support rod  23  switches the state between the folded state and the unfolded state, the driving mechanism drives the at least two deformation rods  22  to rotate around a perpendicular line perpendicular to the support rod  23 , so that the support rod  23  approaches or moves away from the arm  21  to fold or unfold the support rod  23 . 
     In addition, the driving mechanism can also drive the at least two deformation rods  22  to rotate around the center axial line of the arm  21  to adjust the angle between the deformation rods  22  and a perpendicular line, so that when the support rod  23  is used as the stand, the angle between the deformation rods  22  and the perpendicular line is appropriate to improve the support stability, similar to a foldable stand. 
     With reference to  FIG. 1 , the bottom of the center frame  1  is configured to mount the gimbal assembly  4 . The two arm assemblies  2  are located respectively on two sides of the gimbal assembly  4  to prevent the arm assemblies  2  from blocking the gimbal assembly  4 . The gimbal assembly  4  includes a gimbal  41  connected to the bottom of the center frame  1  or a photographing device  42  carried by the gimbal  41 . The driving mechanism drives the deformation rods  22  to rotate to the first position (the position for the support rod  23  at the folded state) or drives the support rod  23  to move translationally relative to the arm  21  to the folded state, the deformation rods  22  are sandwiched between the arm  21  and the support rod  23 , and the arm assembly  2  is above the photographing device  42 . Regardless of whether the deformation rods  22  rotate to the first position, or the support rod  23  moves translationally relative to the arm  21  to the folded state, the support rod  23  is finally folded. The arm assembly  2  is above the photographing device  42  and will not block the photographing device  42 , and the photographing device  42  can rotate 360° for photographing. 
     In some embodiments, the deformation rods  22  and the support rod  23  are at the bottom of the arm  21  to reduce the dimension of the arm assembly  2  on horizontal plane. The deformation rods  22  and the support arm  23  can also be on the side of the arm  21  away from the center frame  1 . 
     With reference to  FIG. 1  and  FIG. 4 , embodiments of the present disclosure also provide an unmanned aerial vehicle (UAV), which includes the frame assembly described above and a power system  5  arranged at the frame assembly. The power system  5  provides flight power to the UAV. 
     The power system  5  may include a propeller assembly. 
     The UAV also includes the gimbal assembly  4  mounted under the center frame  1 . The gimbal assembly  4  includes the gimbal  41  connected to the bottom of the center frame  1  and the photographing device  42  carried by the gimbal  41 . The gimbal  41  may be a two-axis gimbal or a three-axis gimbal, etc. 
     In the embodiments of the present invention, the UAV may be a four-rotor UAV, but is not limited to a four-rotor UAV. For example, the UAV may be an eight-rotor UAV. 
     In the present disclosure, the relationship terms such as “first” and “second” are merely used to differentiate an object or an operation from another object or operation, and do not require or imply any such actual relationship or sequence among these objects or operations. The term “include,” “comprise,” or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, a method, an article or a device that includes a series of elements not only includes those elements, but also includes other elements not explicitly listed or includes the inherent elements of the process, the method, the article or the device. Without further restrictions, the clause reciting an element by “include a . . .” does not exclude the possibility of other identical element existing in the process, the method, the article, or the device that includes the element. 
     The frame assembly of the UAV and the provided UAV provided by embodiments of the disclosure are described above in detail. The principles and the implementation methods of the present disclosure are explained with specific embodiments, and the description of the embodiments is only used to help to understand the methods and the main idea of the present disclosure. One of ordinary skill in the art can modify the specific implementation method and application area based on the idea of the present disclosure. In summary, the content of this specification should not be considered as a restriction to the present disclosure.