Abstract:
A unmanned aerial vehicle (UAV) base station for automated battery pack exchange and methods for manufacturing and using the same. The UAV base station includes a battery-exchange system disposed within a housing having a top-plate. The housing contains a battery array having a plurality of UAV battery packs and a mechanical mechanism for automatically removing an expended battery pack from a UAV that lands on the top-plate and replacing the expended battery pack with a charged battery pack. Thereby, the UAV base station system advantageously enables extended and autonomous operation of the UAV without the need for user intervention for exchanging UAV battery packs.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This is a continuation application of International Application No. PCT/CN2014/083465, filed on Jul. 31, 2014, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates generally to unmanned aerial vehicles (UAVs) and more specifically, but not exclusively, to UAV base stations and methods related thereto. 
       BACKGROUND 
       [0003]    Conventional unmanned aerial vehicles (UAVs) have limited flight time because their battery life is often limited to ten to thirty minutes at the most. When a battery is expended, the UAV needs to land, and the expended battery needs to be exchanged by a user or recharged before the UAV can operate again. 
         [0004]    The necessity for frequent user interaction to maintain and exchange batteries of one or more UAVs is not suitable where extended duty times are required or where extended autonomous operation is desired for a fleet of UAVs. 
         [0005]    In view of the foregoing, a need exists for an improved UAV base station system and method for autonomous exchange of UAV batteries in an effort to overcome the aforementioned obstacles and deficiencies of conventional UAV systems. 
       SUMMARY 
       [0006]    In accordance with the present disclosure, there is provided an unmanned aerial vehicle (UAV) base station includes a landing surface for enabling a UAV having a UAV battery pack to land on the landing surface and a battery-exchange system including a battery-matrix and a mechanical mechanism. The battery-matrix includes a plurality of battery-slots, each of which is configured to removably hold a UAV battery pack. The mechanical mechanism is configured to interact with a selected UAV battery pack of the battery-exchange system and the UAV battery pack of the UAV. 
         [0007]    Also in accordance with the present disclosure, there is provided a method of inserting a UAV battery pack into a UAV. The method includes a mechanical mechanism moving along an X-axis and Y-axis to the UAV battery pack disposed in a selected battery-slot, the mechanical mechanism extending a battery-carriage along a Z-axis and grasping the UAV battery pack, the mechanical mechanism retracting the battery-carriage along the Z-axis to remove the UAV battery pack from the battery-slot, and the mechanical mechanism moving the UAV battery pack proximate to the UAV and inserting the UAV battery pack into a UAV battery-slot disposed on the UAV and decoupling from the UAV battery pack. 
         [0008]    Also in accordance with the present disclosure, there is provided a method of removing a UAV battery pack from a UAV and storing the UAV battery pack. The method includes a mechanical mechanism moving proximate to the UAV having the UAV battery pack disposed in a UAV battery-slot of the UAV, the mechanical mechanism grasping the UAV battery pack disposed in the UAV battery-slot, the mechanical mechanism retractably removing the UAV battery pack from the UAV battery-slot, the mechanical mechanism moving along an X-axis and Y-axis to a selected UAV battery-slot, and the mechanical mechanism extending the battery-carriage along a Z-axis to insert the UAV battery pack in the selected UAV battery-slot. 
         [0009]    Also in accordance with the present disclosure, there is provided a UAV base station including a housing and a UAV fixation system. The housing at least includes a top-plate configured for a UAV to land on the top-plate. The UAV fixation system is configured to direct the UAV present on the top-plate to a battery-exchange zone of the top-plate. 
         [0010]    Also in accordance with the present disclosure, there is provided a portable UAV base station including a battery-exchange system including a battery-matrix and a mechanical mechanism, a housing, and a UAV fixation system. The battery-matrix includes a plurality of battery-slots, each of which is configured to removably hold a UAV battery pack. The mechanical mechanism is configured to interact with the UAV battery pack. The housing at least includes a top-plate configured for a UAV to land on the top-plate. The UAV fixation system is configured to direct the UAV preset on the top-plate to a battery-exchange zone of the top-plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIGS. 1 and 2  are exemplary perspective drawings illustrating an internal portion of an embodiment of a base station for unmanned aerial vehicles (UAVs). 
           [0012]      FIG. 3  is an exemplary perspective drawing illustrating an external portion of the embodiment of the UAV base station of  FIGS. 1 and 2 . 
           [0013]      FIG. 4  is an exemplary perspective drawing illustrating an embodiment of a UAV base station of  FIG. 3 , wherein the UAV base station includes a UAV docked thereon. 
           [0014]      FIG. 5  is a close-up perspective drawing illustrating portions of the UAV base station and the UAV of  FIG. 4 . 
           [0015]      FIGS. 6 a - c    are perspective drawings illustrating another embodiment the UAV base station, wherein the UAV base station includes a lid, draw bar and/or wheels. 
           [0016]      FIG. 7  is a perspective drawing illustrating an embodiment of the UAV base station of  FIGS. 6 a - c   , wherein the UAV base station includes a UAV docked thereon. 
           [0017]      FIG. 8  is a block diagram of a method for inserting a UAV battery pack into a UAV in accordance with an embodiment. 
           [0018]      FIG. 9  is a block diagram of a method for removing, a UAV battery pack from a UAV and storing the UAV battery pack in accordance with an embodiment. 
           [0019]    It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the exemplary embodiments. The figures do not illustrate every aspect of the described embodiments and do not limit the scope of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0020]    Since currently-available unmanned aerial vehicles (UAV) systems are deficient because they fail to provide extended battery life and fail to support battery swapping and recharging, a UAV base station that provides autonomous battery swapping can prove desirable and provide a basis for a wide range of UAV applications, such as the ability for UAV systems to perform longer autonomous missions. This result can be achieved, according to one embodiment disclosed herein, by a UAV base station  100  as illustrated in  FIG. 1 . 
         [0021]    Turning to  FIGS. 1 and 2 , the UAV base station  100  is shown as having a housing  105  that comprises a plurality of sidewalls  106  and a base  107 . The sidewalls  106  and the base  107  cooperatively define a housing cavity  108  in which a plurality of components can disposed including a battery-exchange system  109 . The battery-exchange system  109  comprises a battery-holder  110  that includes a battery-matrix  111  that is offset from the base  107  by legs  112 . 
         [0022]    The battery-matrix  111  forms a plurality of battery-slots  115  that are each configured to hold a battery-pack  120 . For example, as depicted in  FIG. 1 , the battery-matrix  111  comprises two stacked rows of battery-slots  115 , where each row comprises four battery-slots  115 . Although a specific configuration of a battery-matrix  111  is shown and described with reference to  FIGS. 1 and 2 , for purposes of illustration only, any suitable arrangement of a battery-matrix  111  may be provided. The battery matrix  111  can include any suitable number of battery-slots  115 . The number can depend on the number of UAVs, charging time of a battery pack  120 , desired mission time, or the like. For example, some embodiments may include fewer battery-slots  115  or may include many more battery-slots  115 . Battery-slots  115  may have any suitable size and/or shape based on the type of battery-pack  120  for being held therewithin, and, in some embodiments, a battery-matrix  111  may be configured to hold a plurality of uniform and/or different battery pack types, which may include different shapes, cross sections, voltages, currents, or the like. In some embodiments, there may be any suitable number of rows and/or columns in a battery-matrix  111 , and further embodiments may include battery-slots  115  in any other suitable regular or note-regular configuration, that may or may not include rows or columns. In some embodiments, there may be a plurality of battery-matrices  111 , or a battery-matrix  111  may be three dimensional compared to the two dimensional arrangement depicted herein (i.e., a first dimension of rows, and a second dimension of columns). 
         [0023]    The battery-exchange system  109  of  FIGS. 1 and 2  further is shown comprising a mechanical mechanism, such as robotic arm system  125 , that is configured to selectively remove batteries  120  from respective battery-slots  115 , insert batteries  120  into respective battery-slots  115 , and/or remove or couple batteries with a UAV  400  (shown in  FIG. 7 ) as discussed in further detail herein. The embodiment depicted herein includes a Cartesian robotic arm with three degrees of freedom. 
         [0024]    For example, the robotic arm system  125  can include a base-cart  130  that is configured to translate linearly along a pair of base-rails  131  via an X-motor  132  and rotating X-shaft  133  that drives movement of the base-cart  130  along an X-axis. The robotic arm system  125  of  FIGS. 1 and 2  also is shown as further comprising an elevator-carriage  135  that is configured to translate linearly on elevator-rails  236  via a Y-motor  237  and rotating Y-shaft  238  that drives movement of the elevator-carriage  135  along a Y-axis. The elevator-rails  236  extend from and move with the base-cart  130 . 
         [0025]    As shown in  FIGS. 1 and 2 , the robotic arm system  125  can comprise a battery-carriage  140  that is coupled with the elevator-carriage  135  and configured to translate linearly via a Z-motor  141  and rotating Z-shaft  142  that drives movement of the battery-carriage  140  along a Z-axis. The battery-carriage  140  can also include a battery-grabber  143  that is operable to couple with an end region  121  of a selected battery-pack  120  so that batteries  120  can be selectively moved and distributed by the robotic arm system  125 . The battery-grabber  143  comprises a pair of grabber-arms  144  that are configured to grab the end region  121  of batteries  120  and pull the selected battery pack  120  out of the relevant battery-slots  115 , or to insert the selected battery pack  120  into the battery-slots  115  and/or release the battery packs  120 . 
         [0026]    Although  FIGS. 1 and 2  depict a battery-carriage  140  that holds a single battery pack  120 , in some embodiments, a battery-carriage  140  may be configured to hold a plurality of battery packs  120 . For example, it may be desirable to remove an expended battery pack  120  from a UAV  400  and provide a new (or charged) battery pack  120  to the UAV  400  in a single transaction. Accordingly, in some embodiments, the battery-carriage  140  may be configured to remove and hold the expended battery pack and also to hold a charged battery pack  120  to replace the removed battery pack  120  without an intermittent retrieval of a new battery pack  120  from within the housing  105 . 
         [0027]    Additionally, some embodiments include one or more fixation-arm-actuation systems  145   155  are disposed within the housing cavity  108  on respective sidewalls  106 . As depicted in  FIGS. 3 and 4  and as discussed herein the fixation-arm-actuation systems  145 ,  155  may be used to move a UAV  400  to a position on the housing  105  where battery packs  120  can be exchanged. 
         [0028]    The fixation-arm-actuation system  145  comprises a fixation-carriage  146  that is operable to translate on a first fixation-rail  147  via a fixation-motor  148  and fixation-rail  149 . The fixation-motor  148  rotates the first fixation-shaft  149 , which in turn moves the fixation-carriage  146  along the fixation-rail  149 . 
         [0029]    Additionally or alternatively, the fixation-arm-actuation system  155  comprises a fixation-carriage  156  that is operable to translate on a fixation-rail  157  via a fixation-motor  158  and fixation-rail  159 . The fixation-motor  158  rotates the fixation-shaft  159 , which in turn moves the fixation-carriage  156  along the fixation-rail  159 . 
         [0030]    Although two fixation-arm-actuation systems  145 ,  155  are depicted in  FIGS. 1 and 2 , in further embodiments, there may be one or any suitable plurality of fixation-arm-actuation systems  145 ,  155  disposed in any suitable location and on other portions of the housing  105 . 
         [0031]    As depicted in  FIGS. 3 and 4 , first and second fixation arm  310 ,  320  extend through respective slots  312 ,  322  that are defined by a top-plate  308  that further defines the housing  105 . The first and second fixation arm  310 ,  320  are coupled with respective fixation-carriages  146 ,  156  ( FIGS. 1 and 2 ) of the fixation-arm-actuation systems  145 ,  155  shown in  FIGS. 1 and 2 . These components collectively define a UAV fixation system  300 . 
         [0032]    In various embodiments, the UAV fixation system  300  may be operable to direct a UAV  400  disposed on the top-plate  308  to a battery pack exchange zone  340  of the top-plate  308  as shown in  FIG. 3 .  FIG. 4  depicts the UAV  400  disposed in the exchange, zone  340 . Having a UAV fixation system  300  may be advantageous in various embodiments because the UAV fixation system  300  may provide for low accuracy landing of a UAV  400  on the top-plate  308  while subsequently providing for fast movement to the battery pack exchange zone  340 . The UAV battery-pack  120  thereby can be exchanged via the battery pack exchange system  109  (shown in  FIGS. 1 and 2 ). In various embodiments, a UAV fixation system  300  may provide for faster landing of the UAV  400  and faster battery pack exchange compared to requiring precise landing of the UAV  400  in the battery pack exchange zone  340 , which may take more time compared to a low accuracy landing and subsequent positioning; with the UAV fixation system  300 . 
         [0033]    In further embodiments, the UAV fixation system  300  may comprise one or more fixation arm  310 ,  320  that is operable to move one or more UAV  400  disposed on the top-plate  308  to one or more battery pack exchange zone  340 . For example, the UAV base station  100  may comprise a plurality of battery pack exchange zones  340  (e.g., at four corners of the top-plate  308 ) and the UAV fixation system  300  may be operable to move UAVs  400  that land on the top-plate  308  to any of these battery pack exchange zones  340 . The UAV base station  100  may therefore be operable to accommodate a plurality of UAVs  400  simultaneously on the top plate  308 ). In a further embodiment, the UAV fixation system  300  may be configured to queue a plurality of UAVs proximate to a battery pack exchange zone  340 . 
         [0034]    As illustrated in  FIG. 3 , the first fixation arm  310  is operable to tray slate along axis P, and the second fixation arm  320  physically extends in a direction that is substantially perpendicular to the axis P. A first end region  311  of the first fixation arm  310  extends through slots  312  and is coupled to the first, fixation-arm-actuating system  145  disposed in the housing, cavity  108  (shown in  FIGS. 1 and 2 ). A second end region  313  of the first fixation arm  310  may abut or slidably reside within a slot  314 A of a first fixation rim  314 . 
         [0035]    Similarly, the second fixation arm  320  is operable to translate along an axis Q, and the second fixation arm  320  extends in a direction that is substantially perpendicular to the axis Q. A first end region  321  of the second fixation arm  320  extends through slots  322  and is coupled to the second fixation-arm-actuating system  155  disposed in the housing cavity  108  ( FIGS. 1 and 2 ). A second fixation rim  324  may be positioned proximate to the first end region  321 . 
         [0036]    The LANs fixation system  300  may initiate operation by determining that a selected UAV  400  has landed on the top-plate  308 . For example, the first and second fixation arms  310 ,  320  may begin in al riding configuration, positioned at a distal-most position opposing the battery pack exchange zone  340 , and a determination is made that the UAV  400  has landed within the area defined by the first and second fixation arms  310 ,  320  and the first and second fixation rims,  314   324 . The first and second fixation anus  310 ,  320  can then move toward the battery pack exchange zone  340  and thereby physically contact and guide the UAV  400  to the battery pack exchange zone  340  as depicted in  FIG. 4 . The first and second fixation rims,  314 ,  324  also serve as guides for moving the UAV  400  in the battery pack exchange zone  340 . In various embodiments, the UAV  400  may be held in the battery pack exchange zone  340  by the first and second fixation arms  310 ,  320  and/or the first and second fixation rims,  314 ,  324 . 
         [0037]    As shown in  FIGS. 4 and 5 , the top-plate  308  may define a hatch  405 , which is an opening formed in the top-plate  308 . The hatch  405  extends into and provides access between the housing cavity  108  and a portion of the housing  105  above the top-plate  308 . First and second hatch covers  330 A,  330 B can cover the hatch  405 . For example,  FIG. 3  depicts the hatch covers  330  in a closed configuration, and  FIGS. 4 and 5  depict the hatch covers  330  in an open configuration. 
         [0038]    In various embodiments, the hatch doors  330  may be biased toward the closed configuration and may be pushed open by the robotic arm system  125 . As shown in  FIG. 5 . hatch-door actuators  505  may be rods positioned on the elevator-carriage  135  ( FIGS. 1 and 2 ) for opening hatch doors  330 . For example, returning to  FIGS. 1 and 2 , after pulling the selected battery-pack  120  out of a battery-slot  115  and positioning the battery-pack  120  on the battery-carriage  140 , the robotic arm system  125  may move under the hatch  405  as shown in  FIGS. 4 and 5 ). The elevator-carriage  135  may then extend upward toward the hatch  405  with the hatch-door actuators  505  contacting the hatch doors  330  and moving the hatch doors  330  to the open configuration as the elevator-carriage  135  extends upward. 
         [0039]    As illustrated in  FIGS. 4 and 5 , a portion of the robotic arm system  125  may extend through the hatch  405  to facilitate battery pack exchange with the UAV  400  that is disposed on the top-plate  308 . For example, in one aspect of the battery pack exchange, the battery carriage  140  may be empty while extending through the hatch  405  and then the battery carriage  140  may extend toward and grasp a discharged battery-pack  120  that is disposed in the battery-slot  510  of the UAV  400 . In another aspect of battery pack exchange, the battery carriage  140  may have a charged battery-pack  120  disposed thereon while extending through the hatch  405  and then the battery carriage  140  may extend toward an empty UAV battery-slot  510  of the UAV  400  and load the charged battery-pack  120  into the UAV battery-slot  510 . Accordingly,  FIGS. 4 and 5  may depict a battery-pack  120  being loaded onto the UAV  400  and/or may depict a battery-pack  120  being removed from the UAV  400 . 
         [0040]    The battery-exchange system  109  and UAV fixation system  300  described herein can be used in a UAV base station  100  (shown in  FIGS. 1 and 2 ) of various sizes and shapes. For example, in some embodiments, the UAV base station  100  may be as large as a building and may comprise a one or more battery-exchange systems  109  and/or UAV fixation systems  300 . However, in some embodiments, the battery-exchange system  109  and UAV fixation system  300  described herein may be adapted for compact and portable UAV base stations  100  such as the embodiment  100 B depicted in  FIGS. 6 a - c    and  FIG. 7 . 
         [0041]    Turning to  FIGS. 6 a - c    and  FIG. 7 , in such an embodiment  100 B, the housing  105  may be the size and dimensions of conventional luggage and components of the UAV base station  100  may be light weight. The housing  105  may also comprise a top-plate cover  605  that is configured to removably cover the top-plate  308 . The top-plate cover  605  can be rotatable coupled to the housing  105  as depicted in  FIGS. 6 a - c    and  FIG. 7 , but a top-plate cover  605  may alternatively be completely removable, comprise a plurality of portions, or have any other suitable configuration for selectively covering the top-plate  308 . The top-plate cover  605  may also include a latch  610  for securing the top-plate cover  605  in a closed configuration. 
         [0042]    Additionally, the housing  105  may comprise an extendible draw-bar  615  along with wheels  620  and/or legs  625  that provide for further enhanced portability of the base station  100 B. For example, the base station  100 B may be transported by holding the extended draw-bar  615  and rolling the housing  105  along the ground via the wheels  620  or carrying the base station  100 B via the draw-bar  615 . A light-weight and portable base station  100 B may be advantageous because the base station  100 B can be more easily transported via conventional transportation and/or can be setup to support UAVs  400  in locations where larger and heavier base stations  100  might be impractical. For example, the example embodiment base station  100 B may be transported in a conventional vehicle to a desired location and setup on the top of the vehicle (not shown), in a truck-bed of the vehicle, or the like. 
         [0043]    As discussed herein, a UAV base station  100  may support one or more UAV  400  (shown in  FIG. 4 ). For example, the battery-exchange system  109  may provide for the automated exchange of batteries  120  (shown in  FIGS. 1 and 2 ), without ser interaction, for one or more UAV  400  such that the one or tore UAV  400  may remain powered and operable for extended periods of time with no or limited user interaction. Accordingly, in addition to including one or more battery-pack  120  configured for exchange in one or more UAV  400 , the UAV base station  100  may also include a separate power supply (not shown) for charging the one or more batteries  120  that may be present in the UAV base station  100  and/or for powering various components of the UAV base station  100 . Such a power supply may comprise any conventional type of power supply, such a battery, a generator, a solar cell, a connection to a power grid, or the like. Accordingly, in various embodiments, the battery-matrix  110  and one or more of the battery-slots  115  may be configured to charge one or more battery back  120   
         [0044]    The UAV base station  100  may also support one or more UAV  400  in various other Ways. For example, the UAV base station  100  may be operably connected to the UAV  400  via a wired or wireless connection, such that the UAV  400  may communicate with the base station  100  or the UAV  400  may be operable to communicate via a larger network such as the Internet, a satellite network, or the like. In one embodiment, the UAV may wirelessly communicate with one or more UAV  400  via a local wireless network such as Wide Fidelity (WiFi) network, and the base station  100  may be operably connected to the Internet or other suitable network. 
         [0045]    Such connectivity may be desirable so that the UAV  400  may provide data to remote operators, including position data, audio data, image data, temperature data, thermal data, radiological data, RaDAR data, LiDAR data, and/or the like. Such connectivity may also allow a user to remotely operate or otherwise program or provide instructions to a UAV  400  or base station  100 . 
         [0046]    The UAV base station  100  may also include other sensors, which may be operable to provide data to one or more UAVs  400  or to remote operations. For example, the UAV base station  100  may also comprise a GPS unit, compass, accelerometer, RaDAR system, LiDAR system, and/or the like. Additionally, in various embodiments, the UAV base station  100  may be configured to store one or more UAV  400  within the housing cavity  108 , or other portion of the housing  105 . 
         [0047]    In addition to providing for the exchange of batteries  120 , the UAV base station  100  may be advantageously configured for automated exchange or supply of other selected items. For example, a battery-exchange system  109  as described herein may be used or adapted to exchange, supply, or re-supply fuel, memory devices, weaponry, and/or the like. In some embodiments, UAVs  400  may be tasked with discharging or providing liquids, gasses or solids to an area and the UAV base station  100  may be operable to supply such liquids, gasses and/or solids to one or more UAV  400 . 
         [0048]    Additionally, UAVs  400  may be reconfigurable, and the UAV base station  100  may be operable to configure the UAVs  400 . For example, a UAV  400  may configured to modularly and optionally carry a camera, audio system, weapons system, liquid discharge system, gas discharge system and/or the like, and the UAV base station  100  may be operable to configure the UAV  400  accordingly and provide the UAV  400  with one or more desired component or module. 
         [0049]    Turning to  FIG. 8  and the elements of  FIGS. 1-5 , a method  800  for inserting a UAV battery pack  120  into a UAV  400  is illustrated. The method  800  beings in block  810  where a robotic arm system  125  moves along an X-axis and Y-axis to a selected UAV battery pack  120  disposed in a selected battery-slot  115 . In block  820 , the robotic arm system  125  extends a battery-carriage  140  along a Z-axis and grasps the selected UAV battery pack  120 . For example, the battery grabber  143  and/or grabber arms  144  may grasp the selected battery pack  120 . In block  830 , the robotic arm system  12 ( 1  can retract the battery-carriage  140  along the Z-axis to remove the UAV battery pack  120  from the battery-slot  115 . 
         [0050]    In block  840 , the robotic arm system  125  can move the removed UAV battery pack  120  proximate to the UAV  400 . For example, in various embodiments, moving the removed UAV battery pack  120  proximate to the UAV  400  may comprise moving the battery-carriage  140  moving proximate to a hatch  405  and extending the battery-carriage  140  through the hatch  405  and proximate to the UAV  400  that is disposed on the top-plate  308  of the housing  105  in a battery-exchange zone  340 . 
         [0051]    In block  850 , the robotic arm system  125  can insert the UAV battery pack  120  into the UAV battery-slot  510  disposed on the UAV  400  and decouple from the UAV battery pack  120 . In various embodiments the battery grabber  143  and/or grabber arms  144  may decouple from the selected battery pack  120 . The method  800  is done in block  899 . 
         [0052]      FIG. 9  is a block diagram of a method  900  for removing a UAV battery pack  120  from a UAV  400  and storing the UAV battery pack  120  in accordance with an embodiment. The method  900  begins in block  910  where the robotic arm system can move proximate to a UAV  400  having a UAV battery pack  120  disposed thereon in a UAV battery-slot  510 . For example, in various embodiments, moving the robotic arm system  125  proximate to the UAV  400 , may comprise moving die battery-carriage  140  proximate to a hatch  405  and extending the battery-carriage  140  through the hatch  405  and proximate to the UAV  400  that is disposed on the top-plate  308  of the housing  105  in a battery-exchange zone  340 . 
         [0053]    In block  920 , the robotic arm system  125  can grasp the UAV battery pack  120  disposed in the UAV battery-slot  510 . For example, the battery grabber  143  and/or grabber arms  144  may grasp the selected battery pack  120 . In block  930  the robotic arm system  125  can retractably remove the UAV battery pack  120  from the UAV battery-slot  510 . 
         [0054]    In block  930 , the robotic arm system  125  can move along the X-axis and Y-axis to a selected UAV battery-slot  155 . For example, in various embodiments, moving along the X-axis and Y-axis to a selected UAV battery-slot  155  may include retracting through the hatch  405  into the internal cavity  108  of the housing  105  and moving the battery-carriage  140  in alignment with the selected UAV battery-slot  155 . 
         [0055]    In block  940 , the robotic arm system  125  can extend the battery-carriage  140  along a Z-axis to insert the UAV battery pack  120  in the selected UAV battery-slot  115 . In various embodiments, the battery pack  120  may be charged and/or stored in the battery-slot  115  for later charging. 
         [0056]    The described embodiments are susceptible to various modifications and alternative forms, and specific examples thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the described embodiments are not to be limited to the particular forms or methods disclosed, but to the contrary, the present disclosure is to cover all modifications, equivalents, and alternatives.