Patent Publication Number: US-2020283118-A1

Title: Unmanned aerial vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/CN2018/073511, filed Jan. 19, 2018, the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an unmanned aerial vehicle (UAV). 
     BACKGROUND 
     An inertial measurement assembly is used to detect attitude information of a moving object. The inertial measurement assembly generally includes an accelerometer and a gyroscope. The accelerometer is used to detect the acceleration component of the object, and the gyroscope is used to detect the angle information of the object. Due to its ability to measure the three-axis attitude angle (or angular rate) and acceleration of objects, inertial measurement assemblies are usually used as the core components of navigation and guidance, and are widely used in vehicles, ships, robots, and aircrafts that require motion control. 
     The inertial measurement assembly is usually mounted at the body of the UAV. A fixed structure needs to be designed to fix the inertial measurement unit. The inertial measurement assembly, the circuit board and other structures need to avoid each other. Therefore, quite a big space is required, which is not conducive to miniaturization design requirements. 
     SUMMARY 
     In accordance with the disclosure, there is provided an unmanned aerial vehicle (UAV) including a casing including a first end portion and a second end portion away from the first end portion. An accommodation chamber is formed at the second end portion. The UAV further includes a support plate arranged in the casing. The accommodation chamber is recessed relative to the support plate. The UAV also includes a circuit board assembly housed in the casing and a load provided at the first end portion of the casing. The circuit board assembly includes a circuit board connected to the support plate and an inertial measurement assembly provided at the circuit board and accommodated in the accommodation chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To more clearly illustrate the technical solution of the present disclosure, the accompanying drawings used in the description of the disclosed embodiments are briefly described below. The drawings described below are merely some embodiments of the present disclosure. Other drawings may be derived from such drawings by a person with ordinary skill in the art without creative efforts. 
         FIG. 1  is a schematic diagram of an unmanned aerial vehicle and a circuit board assembly according to an embodiment of the disclosure. 
         FIG. 2  is a schematic diagram of the circuit board assembly shown in  FIG. 1 . 
         FIG. 3  is a schematic exploded view of the inertial measurement assembly shown in  FIG. 1 . 
         FIG. 4  is a schematic diagram of an elastic component of the inertial measurement assembly shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The technical solutions in the example embodiments of the present disclosure will be described clearly and completely with reference to the accompanying drawings. The described embodiments are only some of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the scope of the present disclosure. 
     Example embodiments will be described with the reference to the accompanying drawings, in which the same numbers refer to the same or similar elements unless otherwise specified. The implementations described in the following example embodiments do not represent all implementations consistent with the present disclosure. Rather, they are merely examples of devices and methods consistent with some aspects of the invention as detailed in the appended claims. 
     The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not to limit the present disclosure. The singular forms “a,” “said,” and “the” as used in this disclosure include the plural forms, unless the context clearly indicates otherwise. The term “and/or” refers to any or all possible combinations of one or more of the associated items. 
     The UAV of the present disclosure will be described in detail below with reference to the accompanying drawing. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other. 
       FIG. 1  is a schematic diagram of a UAV casing  200  and a circuit board assembly  100  according to an embodiment of this disclosure. The UAV of the embodiment of the present disclosure includes the casing  200 , the circuit board assembly  100  housed in the casing  200 , and a load (not shown) disposed at the casing  200 . The circuit board assembly  100  includes a circuit board  10  and an inertial measurement assembly  30  provided at the circuit board  10 . 
     Referring to  FIG. 1 , in this embodiment, the casing  200  includes a first end portion  201  and a second end portion  202  away from the first end portion  201 . The first end portion  201  of the casing  200  is provided with an accommodation chamber  220  to receive a load (not shown). The second end portion  202  of the casing  200  is provided with a rear-view binocular. The first end portion  201  is opposite to the second end portion  202 . A battery compartment  230  is recessed in a middle position between the first end portion  201  and the second end portion  202  of the casing  200  to receive a battery (not shown). Storing the battery in the middle position is beneficial for maintaining the center of gravity of the UAV. 
     A support plate  205  for connecting the circuit board  10  is formed in the casing  200 . The second end portion  202  is provided with a first accommodation chamber  210 . Relative to the support plate  205 , the first accommodation chamber  210  is recessed toward the bottom of the casing  200 , and the inertial measurement assembly  30  is housed in the first accommodation chamber  210 . Since the inertial measurement assembly  30  is directly arranged at the circuit board  10 , no other special structural parts are needed to fix the inertial measurement assembly  30 , which saves space and facilitates the design needs for miniaturization. At the same time, the first accommodation chamber  210  of the casing  200  is used to house the inertial measurement assembly  30 . The structural characteristics of the casing  200  are used to set the position of the inertial measurement assembly  30  on the casing  200 . Therefore, the space of the casing  200  is fully utilized, the layout is reasonable, and the overall structure is compact. 
     Referring to  FIG. 1 , in this embodiment, the casing  200  has an elongated shape. The first end portion  201  is the nose of the UAV  1 , and the second end portion  202  is the tail of the UAV  1 . The load is disposed at the first end portion  201  of the casing  200 . Specifically, an accommodation chamber  220  may be provided at the bottom of the first end portion  201  of the casing  200  toward the inside of the casing  200  for receiving the load. Correspondingly, the first accommodation chamber  210  is disposed at the second end portion  202  of the casing  200 . The load may include a gimbal, which is used to support a photographing device (such as a camera, a video camera, an infrared camera, an ultraviolet camera, etc.), an audio capturing device, or another sensor. Further, the gimbal can be a two-axis gimbal or a three-axis gimbal, so that the UAV  1  can have multiple different shooting angles by adjusting the gimbal to rotate along different axes. The load may also include other equipment, which is not limited here. 
     In another embodiment, the first end portion  201  may be the tail of the UAV  1  and the second end portion  202  may be the nose of the UAV  1 . That is, in this embodiment, the load is located at the tail of the UAV  1 , and the first accommodation chamber  210  is located at the nose of the UAV  1 . It can be specifically set according to the model and body design of the UAV, and the use requirements, which are not limited here. 
     A cover (not shown) may be further provided above the casing  200 , and the cover is used to enclose the circuit board assembly  100  in the casing  200 . 
     Referring to  FIG. 3 , the inertial measurement assembly  30  includes a mounting bracket  31 , an inertial measurement unit  32 , and a shock absorption mechanism  33  connecting the mounting bracket  31  and the inertial measurement unit  32 . The mounting bracket  31  is used for mounting the inertial measurement assembly  30  at the circuit board  10 . 
     In the above embodiment, the mounting bracket  31  includes a main body  311  that fits with the shock absorption mechanism  33  and a mounting portion  312  provided at an edge of the main body  311 . The mounting portion  312  is used to mount the inertial measurement assembly  30  at the circuit board  10 . 
     In an embodiment, the mounting portion  312  protrudes from the main body  311  toward the circuit board  10 , so that there is a certain distance between the main body  311  and the circuit board  10 , and thus the inertial measurement unit  32  has a certain moving space. Therefore, when the UAV  1  impacts, the inertial measurement unit  32  will not collide with the electronic components on the circuit board  10  and affect its performance. 
     Referring to  FIGS. 1 to 3 , the circuit board  10  is provided with a stud  13 . The mounting portion  312  and the stud  13  are fixed together by a fastener. Specifically, the mounting portion  312  is provided with a connection hole  3121 . The mounting portion  312  is sleeved on the outside of the stud  13  through the connection hole  3121  and fitted with a screw hole  131  of the stud  13  by a fastener such as a screw, so that the inertial measurement assembly  30  is fixed to the circuit board  10 . 
     In some embodiments, the circuit board  10  is provided with a through hole, and the mounting portion  312  is provided with a threaded hole. A screw passes through the through hole of the circuit board  10  and fits with the threaded hole of the mounting portion  312 . 
     In some other embodiments, the mounting bracket  31  may also be fixed to the circuit board  10  by snapping, bonding, soldering, or the like. 
     In the illustrated embodiment, the stud  13  can be fixed at the circuit board  10  by reflow soldering, which is not limited here. In this embodiment, three studs  13  are provided, of which two studs  13  are near two corners of one end of the circuit board  10  and another stud  13  is provided at a middle position of the circuit board  10 . The three studs  13  form an isosceles or equilateral triangle. When the mounting portion  312  of the mounting bracket  31  is fixed with the three studs  13 , it can provide stable support for the inertial measurement assembly  30 . In other embodiments, the number of studs  13  and positions on the circuit board  10  may be determined according to specific design requirements, which are not limited here. For example, the number of the studs  13  may also include 2, 4 and so on. 
     In another embodiment, the inertial measurement assembly  30  includes an inertial measurement unit  32  and a shock absorption mechanism  33 . In this embodiment, the shock absorption mechanism  33  is directly connected between the inertial measurement unit  32  and the circuit board  10  without a mounting bracket. 
     Referring to  FIG. 3 , the inertial measurement unit  32  includes a protective casing  321  and an inertial measurement module  322  disposed in the protective casing  321 . The shock absorption mechanism  33  is connected to the protective casing  321 . 
     The protective casing  321  includes an upper casing  3211  and a lower casing  3212  that matches with the upper case  3211 . The inertial measurement module  322  is disposed between the upper casing  3211  and the lower casing  3212 . The protective casing  321  is provided with an accommodation chamber  3210  for receiving the inertial measurement module  322 . The accommodation chamber  3210  may be provided in the upper casing  3211  or the lower casing  3212 , or partly provided in the upper casing  3211  and partly provided in the lower casing  3212 . In the illustrated embodiment, the accommodation chamber  3210  is disposed in the upper casing  3211 , and the inertial measurement unit  32  can be fixed in the accommodation chamber  3210  by double-sided adhesive bonding, glue fixing, screw fixing, and the like. 
     In some embodiments, the upper casing  3211  includes an inner casing  32111  and an elastic casing  32112  covering the inner casing  32111 . The accommodation chamber  3210  is disposed at the inner casing  32111 . The elastic casing  32112  is used to reduce the impact on the peripheral side of the inertial measurement unit  32 . The elastic casing  32112  is made of some elastic material. In the illustrated embodiment, the elastic casing  32112  is made of low-hardness silicone rubber. The silicone rubber can be heated and injected to cover the inner casing  32111 . In some other embodiments, other elastic materials such as foam, thermoplastic elastomer, and etc. can be adopted, and they are not limited to these. The inner casing  32111  may be a plastic casing or a low-hardness metal casing. In this embodiment, a plastic casing is used as the inner casing  32111  to reduce the self-weight of the inertial measurement unit  32  and contribute to the weight reduction of the UAV. 
     Referring to  FIG. 3 , the lower casing  3212  includes a main body portion  32121  and a pair of holding arms  32122 . The main body portion  32121  may be in a square shape. The pair of holding arms  32122  are oppositely disposed at both sides of the main body portion  32121  and used for holding and matching with the upper casing  3211 , so that the inertial measurement module  322  can be enclosed and fixed. In this embodiment, the holding arm  32122  is an elastic structure. A hook  32123  is provided at the inner side of the free end of the holding arm  32122 , and a slot  32114  matching with the hook  32123  is provided at the upper casing  3211 . When the upper casing  3211  and the lower casing  3212  are assembled, the holding arm  32122  clamps the upper casing  3211  and the hook  32123  is fitted in the slot  32114 , so that the upper casing  3211  and the lower casing are assembled. During disassembly, the external force acts on the holding arm  32122  and the holding arm  32122  elastically deforms outward, so that the hook  32123  is separated from the slot  32114 . Therefore, the upper casing  3211  and the lower casing  3212  can be separated. 
     In some embodiments, a connecting portion  32124  is further extended on one side of the lower casing  3212 . The connecting portion  32124  and the corresponding portion of the upper casing  3211  are connected by fasteners. In this way, the upper and lower casings are fixed by fasteners and the holding arms  32122 . 
     In the illustrated embodiment, the inertial measurement module  322  includes a control circuit board  3221 , an inertial measurement body  3222  disposed at the control circuit board  3221 , a thermal resistor  3223 , and a connection line  3224  connected to the circuit board  10  of the UAV. The thermal resistor  3223  is provided around the inertial measurement body  3222 . The inertial measurement body  3222  and the thermal resistor  3223  are located on the opposite side of the control circuit board  3221  and the lower casing  3212 . One end of the connection line  3224  is connected to the control circuit board  3221  and the other end is connected to the circuit board  10 , so that a communication is established between the control circuit board  3221  and the circuit board  10  of the UAV. In some embodiments, the connection line  3224  uses FPC (Flexible Printed Circuit) to save space. 
     The inertial measurement unit  32  further includes a thermal conductive structure  35 , which is disposed between the inertial measurement module  322  and the lower casing  3212 . The upper casing  3211  matching with the lower casing  3212  encloses the inertial measurement module  322  and the thermal conductive structure  35 . In this embodiment, the thermal conductive structure  35  is made of thermal conductive silicone grease, which is used to cover the inertial measurement body  3222  and the thermal resistor  3223 , and transfer the heat generated by the thermal resistor  3223  to the inertial measurement body  3222 . Therefore, the inertial measurement body  3222  can work at a constant temperature with the heat insulation and its working stability can be enhanced. In other embodiments, the thermal conductive structure  35  can be made of other thermal insulation materials, which are not limited to the thermal conductive silicone grease. 
     In some embodiments, the lower casing  3212  is further provided with a locking member  32126  extending in a direction away from the upper casing  3211 , which is used to lead out the connection line  3224  from below the lower casing  3212  and restrict the connection line  3224  under the lower casing  3212 . Therefore, the stress generated by the inertial measurement body  3222  and the connection line  3224  in use can be reduced. 
     Referring to  FIG. 3 , the shock absorption mechanism  33  includes a plurality of elastic members  330 , and the plurality of elastic members  330  are respectively disposed at the edges of the protective casing  321 . Each of the elastic members  330  is disposed between the mounting bracket  31  and the protective casing  321  for damping on the inertial measurement module  322 . The distance between two adjacent elastic members  330  can be set according to specific design requirements. 
     In one embodiment, a plurality of elastic members  330  are evenly arranged between the mounting bracket  30  and the protective casing  321  to achieve a better shock absorption effect. One end of the elastic member  330  is connected to the mounting bracket  30 , and the other end is connected to the protective casing  321 . When the UAV is impacted, the vibration is transmitted to the inertial measurement module  322  through the elastic member  330  with the deformation buffering to achieve the effect of damping. In the illustrated embodiment, the protective casing  321  is approximately a square. Four elastic members  330  are provided, which are arranged at opposite corners of the protective casing  321 , respectively. The number and arrangement of the elastic members  330  can be set according to design requirements, which are not limited herein. 
     The elastic member  330  is made of elastic materials with a certain damping effect, and the damping coefficients of the plurality of elastic members  330  are the same, so that the shock absorption effect on the inertial measurement module  322  can be balanced. The materials of the plurality of elastic members  330  may be the same or different. The elastic member  330  includes at least one of the following: a shock absorption ball, a spring, a spring leaf, and a shock absorption gasket, which are not limited thereto. 
     Referring to  FIG. 4 , the elastic member  330  is a shock absorption ball. The shock absorption ball includes an upper end portion  331 , a shock absorption body  333 , and an upper neck portion  332  connecting the upper end portion  331  and the shock absorption body  333 . The shock absorption body  333  abuts against the protective casing  321  to absorb shock of the protective casing  321 , therefore a shock absorption effect on the inertial measurement module  322  is achieved. 
     The protective casing  321  is provided with a first mounting hole  3218  that fits with the upper neck portion  332 . In the illustrated embodiment, the first mounting hole  3218  is provided at the upper casing  3211 . In other embodiments, the first mounting hole  3218  may also be provided at the lower casing  3212 . The upper neck portion  332  passes through the first mounting hole  3218 . The axial height of the upper neck portion  332  is smaller than the depth of the first mounting hole  3218 , so that the shock absorption body  333  abuts against the protective casing  321 , and the upper end portion  331  and the shock absorption body  333  fit in the protective casing  321 . In this way, the shaking of the protective casing  321  relative to the elastic member  330  can be effectively reduced, and a better shock absorption effect can be achieved. 
     The shock absorption ball further includes a lower end portion  335  and a lower neck portion  334  connecting the lower end portion  335  and the shock absorption body  333 . The lower neck portion  334  and the lower end portion  335  are used to connect with the mounting bracket  30 , and the shock absorption body  333  abuts against the mounting bracket  30 . 
     The mounting bracket  30  is provided with a second mounting hole  313  that fits with the lower neck portion  334 . The lower neck portion  334  passes through the second mounting hole  313 . The axial height of the lower neck portion  334  is smaller than the depth of the second mounting hole  313 , so that the shock absorption body  333  abuts against the mounting bracket  30 , and the lower end portion  335  and the shock absorption body  333  fit in the mounting bracket  30 . In this way, the shaking of the protective casing  321  relative to the elastic member  330  can be effectively reduced, and a better shock absorption effect can be achieved. 
     The shock absorption body  333  may be spherical, approximately spherical, hemispherical, square, or elliptical in cross section, and the like. In the illustrated embodiment, the shock absorption body  333  is spherical, which makes the shock absorption body  333  abut against both the mounting bracket  31  and the inertial measurement unit  32 . The vibration is transmitted to the inertial measurement unit  32  through the shock absorption body  333  with the deformation buffer, therefore the effect of shock absorption is achieved. The shock absorption body  333  may be solid or hollow. In one embodiment, the shock absorption body  333  is hollow to get better elasticity and reduce weight at the same time, which helps to realize the lightweight of the UAV. 
     In the illustrated embodiments, all parts of the shock absorption ball are integrally formed. In other embodiments, the upper end portion  331 , the upper neck portion  332 , the shock absorption body  333 , the lower neck portion  334 , and the lower end portion  335  of the shock absorption ball may be separately molded, and then assembled together. 
     The circuit board assembly  100  further includes a flight control circuit disposed at the circuit board  10 . The inertial measurement assembly  30  transmits its inertial measurement data to the flight control circuit. 
     The flight control circuit is the core component of the UAV, and as the central controller of the UAV, is used to control the main functions of the UAV. For example, the flight control circuit can be used to manage the operation mode of the UAV&#39;s control system, to calculate the control rate and generate control signals, to manage the sensors and servo systems of the UAV, to control other tasks and electronic components of the UAV, to exchange data, and to receive instructions from ground to control the UAV&#39;s flight and collect the attitude information of the UAV. 
     The inertial measurement assembly  30  is configured to determine the attitude information of the UAV and transmit the determined attitude information to the flight control circuit, so that the flight control circuit determines subsequent operations. The process of determining the attitude information of the UAV by the inertial measurement assembly  30  includes the accelerometer (i.e., acceleration sensor) detecting the acceleration component of the UAV relative to the geographic vertical, the gyroscope (i.e., velocity sensor) detecting the angle information of the UAV, the analog-to-digital converter receiving the analog variables output by each sensor and converting the analog variables into digital signals, the flight control circuit determining and outputting at least one of the pitch angle, the roll angle, or the yaw angle of the UAV based on the digital, thereby determining the attitude information of the UAV. 
     In the present disclosure, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. The term “comprising,” “including” or any other variation thereof is non-exclusive inclusion, such that a process, method, article, or device that include a series of elements include not only those elements but also other elements that are not explicitly listed, or elements that are inherent to such a process, method, article, or device. Without more restrictions, the elements defined by the sentence “including a . . . ” do not exclude the existence of other identical elements in the process, method, article, or equipment that includes the elements. 
     The methods and devices provided by the present disclosure are described in detail above. Specific examples are used to explain the principles and implementation of the present disclosure. The descriptions of the above embodiments are only for facilitating the understanding of the present disclosure; meanwhile, for a person of ordinary skill in the art, according to the present disclosure, there will be changes in the specific implementation and application. In summary, the content of this specification is not a limitation to this disclosure. 
     The content disclosed in this disclosure contains material which is subject to copyright protection. The copyright is owned by the copyright owner. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the official records and archives of the Patent and Trademark Office.