Abstract:
Various embodiments of the present disclosure provide an apparatus and method for launch and retrieval of a hovering aircraft. Generally, the apparatus of the present disclosure is configured to capture a hovering aircraft between two or more fingers of an aircraft capturer, guide the captured aircraft into a docking station for servicing and/or storage, and launch the aircraft from the docking station. The apparatus of the present disclosure is thus configured to bring the aircraft from an imprecise, irregular hover into a secure and well-controlled rest state. The tolerance of imprecision provided by the apparatus makes it particularly suited for use under a practical conditions such as aboard a small boat in a rough sea.

Description:
PRIORITY CLAIM 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/881,188, filed on Sep. 23, 2013, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Hovering aircraft, be they helicopters, thrust-vectoring jets, “tail-sitters,” or other types, usually land by gently descending in free thrust-borne flight onto a landing surface and coming to rest on an undercarriage of wheels, skids, or legs. This elementary technique can be problematic in certain conditions, such as when targeting a small, windswept landing pad on a ship moving in a rough sea. The well-known Beartrap or Recovery Assist, Secure, and Traverse (RAST) system and the well-known harpoon-and-grid system are used by helicopters to permit retrieval with acceptable safety in such conditions. These systems require an expensive and substantial plant in the landing area, as well as manual operations coordinated between the helicopter and the shipboard crew. Furthermore, the helicopter must carry a complete undercarriage in addition to the components necessary for capturing the retrieval apparatus, adding size and weight to the helicopter. 
         [0003]    Thus, there is a continuing need to provide improved apparatuses and methods for capturing hovering aircraft from free thrust-borne flight including: (a) simplified base apparatuses; (b) simplified apparatuses (if any) onboard the hovering aircraft; and (c) automated operation encompassing retrieval, subsequent servicing, and launch. 
       SUMMARY 
       [0004]    Various embodiments of the present disclosure provide an apparatus and method for launch and retrieval of a hovering aircraft. Generally, the apparatus of the present disclosure is configured to capture a hovering aircraft between two or more fingers of an aircraft capturer, guide the captured aircraft into a docking station for servicing and/or storage, and launch the aircraft from the docking station. The apparatus of the present disclosure is thus configured to bring the aircraft from an imprecise, irregular hover into a secure and well-controlled rest state. The tolerance of imprecision provided by the apparatus makes it particularly suited for use under a practical conditions such as aboard a small boat in a rough sea. 
         [0005]    In various embodiments, the apparatus of the present disclosure is configured to: (a) detect movement of a hovering aircraft; (b) automatically cause the aircraft capturer to move in a manner corresponding to the detected movement of the aircraft such that the aircraft capturer follows or tracks the aircraft while maintaining a designated distance from the aircraft; (c) when tracking is satisfactory, automatically cause the aircraft capturer to capture the aircraft between two fingers quickly enough so that any motion between the point in time at which the decision is made to capture the aircraft and the capture itself is negligible; and (d) if unwanted contact threatens, quickly move away from the aircraft in order to prevent collision. 
         [0006]    In other embodiments, the apparatus of the present disclosure is configured to cause the aircraft capturer to capture a wing of the aircraft between two jaws each including two fingers and automatically draw the captured aircraft into a desired position proximate the aircraft capturer by spinning the fingers. 
         [0007]    In other embodiments, the apparatus of the present disclosure is configured to cause the aircraft capturer to capture a fuselage of the aircraft between two fingers and automatically draw the captured aircraft into a desired position proximate the aircraft capturer by spinning the fingers. 
         [0008]    In various embodiments, after the aircraft capturer captures the aircraft, the apparatus automatically guides the captured aircraft into a docking station. Once secured in the docking station, the aircraft is shut down and the aircraft may be serviced. After any servicing is performed on the aircraft, the aircraft may be launched by substantially reversing the process by which the aircraft was captured. 
         [0009]    Additional features and advantages are described herein, and will be apparent from, the following Detailed Description and the Figures. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]      FIG. 1A  illustrates an aircraft stationkeeping in the vicinity of an example embodiment of the apparatus of the present disclosure. 
           [0011]      FIG. 1B  illustrates the aircraft moving radially away from an aircraft capturer of the apparatus of  FIG. 1A  along a substantially horizontal plane. 
           [0012]      FIG. 1C  illustrates the apparatus of  FIG. 1A  detecting the aircraft&#39;s movement and automatically causing the aircraft capturer to move radially outward to follow the aircraft. 
           [0013]      FIG. 1D  illustrates the aircraft moving azimuthally to the right of the aircraft capturer of the apparatus of  FIG. 1A . 
           [0014]      FIG. 1E  illustrates the apparatus of  FIG. 1A  detecting the aircraft&#39;s movement and automatically causing the aircraft capturer to move azimuthally to the right to follow the aircraft. 
           [0015]      FIG. 1F  illustrates the aircraft increasing its altitude and moving radially toward the aircraft capturer of the apparatus of  FIG. 1A . 
           [0016]      FIG. 1G  illustrates the apparatus of  FIG. 1A  detecting the aircraft&#39;s movement and automatically causing the aircraft capturer to increase its altitude and move radially inward to follow the aircraft. 
           [0017]      FIG. 1H  illustrates the apparatus of  FIG. 1A  after capturing the aircraft. 
           [0018]      FIG. 2A  illustrates an aircraft stationkeeping in the vicinity of another example embodiment of the apparatus of the present disclosure. 
           [0019]      FIG. 2B  illustrates the apparatus of  FIG. 2A  after capturing the aircraft. 
           [0020]      FIG. 2C  illustrates the apparatus of  FIG. 2A  transporting the captured aircraft toward the base of the apparatus. 
           [0021]      FIG. 2D  illustrates the apparatus of  FIG. 2A  after transporting the captured aircraft to the base. 
           [0022]      FIG. 3A  illustrates an aircraft stationkeeping in the vicinity of another example embodiment of the apparatus of the present disclosure. 
           [0023]      FIGS. 3B ,  3 C, and  3 D illustrate the apparatus of  FIG. 3A  after capturing a wing of the aircraft. 
           [0024]      FIGS. 3E and 3F  illustrate the fingers of aircraft capturer of the apparatus of  FIG. 3A  spinning to cause the aircraft to move into a desired position with respect to the aircraft capturer. 
           [0025]      FIGS. 3G and 3H  illustrate the aircraft in the desired position with respect to the aircraft capturer. 
           [0026]      FIG. 3I  illustrates the apparatus of  FIG. 3A  sliding the aircraft capturer toward the distal end of the upper arm in preparation for docking. 
           [0027]      FIG. 3J  illustrates the fingers of the apparatus of  FIG. 3A  spinning to cause the aircraft to move into a desired position for launch. 
           [0028]      FIGS. 3K and 3L  illustrate the apparatus of  FIG. 3A  releasing the wing of the aircraft and pushing the aircraft into free thrust-borne flight. 
           [0029]      FIG. 4A  illustrates an aircraft stationkeeping in the vicinity of another example embodiment of the apparatus of the present disclosure. 
           [0030]      FIG. 4B  illustrates the aircraft contacting the fingers of the aircraft capturer of the apparatus of  FIG. 4A . 
           [0031]      FIG. 4C  illustrates the apparatus of  FIG. 4A  sliding the aircraft capturer toward the distal end of the upper arm to capture the aircraft. 
           [0032]      FIG. 4D  illustrates the fingers of the apparatus of  FIG. 4A  spinning to cause the aircraft to move into a desired position with respect to the aircraft capturer. 
           [0033]      FIG. 4E  illustrates the aircraft in the desired position with respect to the aircraft capturer and the wing restraint pivoted into place. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    Various example embodiments of the apparatus of the present disclosure are described below. 
       First Example Embodiment 
       [0035]    In this example embodiment, the apparatus of the present disclosure is configured to: (a) detect movement of a hovering aircraft; (b) automatically cause the aircraft capturer to move in a manner corresponding to the detected movement of the aircraft such that the aircraft capturer follows or tracks the aircraft while maintaining a designated distance from the aircraft; (c) when tracking is satisfactory and the movement of the aircraft is stabilized, automatically cause the aircraft capturer to capture the aircraft between two fingers quickly enough so that any motion between the point in time at which the decision is made to capture the aircraft and the capture itself is negligible; and (d) if unwanted contact threatens, quickly move away from the aircraft in order to prevent collision. 
         [0036]    Turning to the Figures,  FIGS. 1A to 1H  illustrate this example embodiment of the apparatus, which is generally indicated by numeral  100  and includes: (a) a rotatable base  110  anchored or otherwise attached to a surface  2000  (such as the deck of a ship at sea) such that the base  110  is configured to rotate relative to the surface  2000  about a substantially vertical axis through a center of the base  110 ; (b) a lower or first arm  130  pivotably connected at a first end to the base  110  via a revolute joint such that the lower arm  130  is configured to pivot about a substantially horizontal axis through the connection to the base  110 ; (c) an upper or second arm  140  pivotably connected at a first end to a second end of the lower arm  130  via a revolute joint such that the upper arm  140  is configured to pivot about a substantially horizontal axis through the connection to the lower arm  130 ; and (d) an aircraft capturer  150  pivotably connected to a second end of the upper arm  140  via a revolute joint such that the aircraft capturer  150  is configured to pivot about a substantially horizontal axis through the connection to the upper arm  140 . 
         [0037]    The aircraft capturer  150  includes two fingers  155  having an open configuration (as shown in  FIGS. 1A to 1G ) and a closed configuration (as shown in  FIG. 1H ). In this example embodiment, the fingers  155  each include: (a) a generally solid support; (b) a cushioned material (such as foam) at least partially surrounding the support and configured to partially conform to the fuselage of the aircraft  10  when the fingers  155  capture the aircraft  10  (as shown in  FIG. 1H ); and (c) a protective layer or coating of high-friction material such as friction tape, suction cups, or soft rubber substantially covering an outer surface of the cushioned material. In other embodiments (such as the second example embodiment described below), the fingers do not include the cushioned material or the layer of high-friction material. In certain embodiments (such as the second example embodiment described below), the fingers are curved or contoured in the shape of the fuselage of the aircraft. In further embodiments, the fingers include a plurality of components connected by revolute joints such that multiple components of the fingers may pivot relative to one another. In various embodiments, the fingers are magnetic or include electro-magnets that facilitate capture of the aircraft by attracting one or more magnetic components of the aircraft. 
         [0038]    Although not shown, the apparatus  100  includes a controller configured to control movement of: (a) the base  110 , (b) the lower arm  130 , (c) the upper arm  140 , and (d) the aircraft capturer  150  (including the fingers  155 ). 
         [0039]    In this example embodiment, the aircraft  10  includes a generally cylindrical fuselage  12  including a nose end and a tail end, a main rotor  16  near the nose end of the fuselage  12 , and a plurality of opposing wings  14  each connected to and extending transversely from the fuselage  12  at a first end and including a thruster  18  at a second end opposite the first end. The main rotor  16  is configured to control pitch and yaw with rotor cyclic (similar to a conventional helicopter), while the thrusters  18  facilitate control in roll (i.e., control about the spin axis of the main rotor  16 ). It should be appreciated that the aircraft is one example aircraft, and that the apparatus of the present disclosure may be employed to capture any suitable aircraft. 
         [0040]    In this example embodiment, the apparatus  100  is configured to measure a variety of different parameters or properties of the aircraft  10  to facilitate capture. Here, the apparatus measures: (a) the altitude of the aircraft  10  (such as relative to the aircraft capturer  150 , the base  110 , or any other suitable point); (b) the azimuthal position of the aircraft  10  (relative to any suitable point); (c) the radial position of the aircraft  10  (relative to any suitable point); (d) the global position of the aircraft  10 ; (e) the components of the velocity of the aircraft  10 ; (f) the components of the velocity of the aircraft  10  relative to any suitable point (such as the surface  2000 , which may be moving); and (g) the attitude (e.g., the pitch, roll, and yaw) of the aircraft  10 . It should be appreciated that the apparatus may measure any suitable parameters or properties of the aircraft  10 . It should also be appreciated that the apparatus  100  does so in any suitable manner, such as via one or more sensors (such as optical sensors), a real time kinematic global positioning system, and/or any other suitable measuring devices on one or more components of the apparatus  100  or the aircraft  10 . 
         [0041]    As illustrated in  FIG. 1A , in preparation for capture, the aircraft  10  stationkeeps spanwise-to-wind relative to the surface  2000  (such as at a radial distance from the surface  2000  approximately equal to a diameter of the main rotor  16 ) such that the aircraft  10  is near the apparatus  100 . Stationkeeping will normally be imperfect due to, for example, gusty, unpredictable winds and rough seas. As the aircraft  10  moves relative to the aircraft capturer  150 , the apparatus  100  monitors the position of the aircraft  10  relative to the aircraft capturer  150 . The apparatus  100  (and, more specifically, the controller) automatically manipulates the base  110 , the lower arm  130 , and/or the upper arm  140  to cause the aircraft capturer  150  to move in a manner corresponding to the movement of the aircraft such that the aircraft capturer  150  follows or tracks the movement of the aircraft  10  while maintaining a designated radial distance from the aircraft  10 , as shown in  FIGS. 1B to 1G . 
         [0042]    More specifically, as shown in  FIG. 1B , the aircraft  10  moves radially away from the aircraft capturer  150  along a substantially horizontal plane, and as shown in  FIG. 1C , the apparatus  100  detects this movement of the aircraft  10  and automatically causes the aircraft capturer  150  to move radially outward along a substantially horizontal plane (i.e., in a manner corresponding to the detected movement of the aircraft  10 ) to follow or track the aircraft  10 . As shown in  FIG. 1D , the aircraft  10  moves azimuthally to the right of the aircraft capturer  150  along a substantially horizontal plane, and as shown in  FIG. 1E , the apparatus  100  detects this movement of the aircraft  10  and automatically causes the aircraft capturer  150  to move azimuthally to the right along a substantially horizontal plane (i.e., in a manner corresponding to the detected movement of the aircraft  10 ) to follow or track the aircraft  10 . As shown in  FIG. 1F , the aircraft  10  increases its altitude and moves radially toward the aircraft capturer  150  along a substantially horizontal plane, and as shown in  FIG. 1G , the apparatus  100  detects this movement of the aircraft  10  and automatically causes the aircraft capturer  150  to increase its altitude and move radially backward along a substantially horizontal plane (i.e., in a manner corresponding to the detected movement of the aircraft  10 ) to follow or track the aircraft  10 . 
         [0043]    As shown in  FIG. 1H , when tracking is satisfactory and the movement of the aircraft is stabilized (such as when: (i) the altitude, azimuthal position, and radial position of the aircraft  10  are within designated ranges; (ii) the velocity components of the aircraft  10  are within designated ranges; and (iii) the components of the attitude of the aircraft  10  are within designated ranges), the apparatus  100  automatically: (a) moves the aircraft capturer  150  towards the aircraft  10  such that a portion of the fuselage  12  of the aircraft  10  aft of the wings  14  and near the center of mass of the aircraft  10  is positioned between the fingers  155 ; and (b) manipulates the fingers  155  into the closed configuration such the fingers  155  capture the fuselage  12  (and, therefore, the aircraft  10 ) therebetween. It should be appreciated that, in this example embodiment, the fingers  155  capture the fuselage aft of the wings  14  and near the center of mass of the aircraft  10 . It should be appreciated that capturing the aircraft  10  near its center of mass (as opposed to near the tail of the aircraft  10 ) prevents the apparatus  100  from imposing unrecoverable pitch and yaw loads, which enables the aircraft  10  to continue to exercise effective attitude and altitude control (explained below). 
         [0044]    It should be appreciated that after the apparatus determines that tracking is satisfactory, the apparatus captures the hovering aircraft quickly enough so that any motion between the point in time at which the decision is made to capture the hovering aircraft and capture itself is negligible. 
         [0045]    In this example embodiment, once the aircraft capturer  150  captures the aircraft  10 , the apparatus  100  constrains the azimuthal and radial components of the movement of the aircraft  10 , while the main rotor  16  of the aircraft  10  continues to spin to support the weight of the aircraft  10  and to enable the aircraft  10  to continue regulating the attitude and altitude of the aircraft  10 . The fingers  155  hold the aircraft  10  with enough force to prevent the aircraft  10  from pulling free. Since the apparatus  100  need not support the weight of the aircraft  10  after capture in this example embodiment, the size and cost of the apparatus  100  may be minimized. 
         [0046]    While the above-described Figures illustrate a lag between the movement of the aircraft and the corresponding following or tracking movement of the aircraft capturer, it should be appreciated that, in operation, the combination of the large amount of measured information regarding the aircraft&#39;s movement and position and the relatively light weight of the apparatus provides the apparatus with high bandwidth such that it is configured to cause the aircraft capturer to follow the aircraft with negligible lag and, in certain embodiments, to centimeter accuracy. 
         [0047]    It should be appreciated that the designated radial distance from the aircraft that the apparatus maintains while tracking the aircraft is large enough to ensure that the aircraft will not unintentionally collide with the aircraft capturer (e.g., is a safe distance from the aircraft). That is, in addition to automatically causing the aircraft capturer to track or follow the movement of the aircraft, the apparatus is configured to automatically cause the aircraft capturer (and the other components of the apparatus) to evade the aircraft should collision threaten. For instance, the aircraft capturer and the aircraft are maintained the designated radial distance apart such that if strong wind unexpectedly blows the aircraft toward the aircraft capturer, the apparatus can quickly detect this unexpected and potentially hazardous movement and cause the aircraft capturer to evade the movement of the aircraft. 
         [0048]    In certain embodiments, after the aircraft capturer captures the aircraft, the apparatus automatically guides the captured aircraft into a docking station (not shown). Once secured in the docking station, the aircraft is shut down, the main rotor is stopped, and the aircraft may be serviced. After any servicing is performed on the aircraft  10 , the apparatus  100  may launch the aircraft  10  by substantially reversing the above-described process. More specifically, to launch the aircraft  10 : (a) the aircraft  10  re-starts its engine (such as by using an internal starter or a starter incorporated into the docking station); (b) the apparatus  100  automatically re-captures the aircraft  10 ; (c) the aircraft pulls itself out of the docking station and stationkeeps near the surface  2000 ; and (d) when the aircraft  10  is sufficiently clear of any obstacles and is determined to be stationkeeping properly (e.g., no sag is detected in the upper arm  140 ), the apparatus  100  releases the aircraft  10  into free thrust-borne flight while quickly maneuvering away from the aircraft  10 . 
         [0049]    It should be appreciated that, in other embodiments, the base is: (a) non-rotatable, or (b) configured to move in one or more manners instead of or in addition to rotation, such as swiveling or pivoting about a substantially horizontal axis. In another embodiment, the aircraft capturer is configured to rotate about a substantially horizontal axis to enable the aircraft capturer to account for the aircraft having a non-vertical orientation. 
       Second Example Embodiment 
       [0050]      FIGS. 2A to 2D  illustrate a second example embodiment of the apparatus of the present disclosure, which is generally indicated by numeral  200  and includes: (a) a base  210  anchored or otherwise attached to the surface  2000 ; (b) a substantially vertical lower or first arm  230  extending from the base  210 ; (c) a sleeve or upper arm supporter  235  rotatably and pivotably connected to an upper end of the first arm  230  such that the sleeve  235  is configured to: (i) rotate relative to the first arm  230  about a substantially vertical axis through the center of the first arm  230 , and (ii) pivot about a substantially horizontal axis through the connection to the first arm  230 ; (d) an upper or second arm  240  mounted within the sleeve  235  such that the upper arm  240  is configured to move axially through the sleeve; (e) an aircraft capturer  250  connected to a first end of the upper arm  240  via a ball-and-socket joint; and (f) a counterweight  260  mounted to the upper arm  240  between a second end of the upper arm  240  and the sleeve  235  such that the counterweight  260  is configured to move axially along the upper arm  240 . The aircraft capturer  250  includes two fingers  255  contoured to the shape of the fuselage of the aircraft and having an open configuration (as shown in  FIG. 2A ) and a closed configuration (as shown in  FIGS. 2B to 2D ). 
         [0051]    Although not shown, the apparatus  200  includes a controller configured to control movement of: (a) the sleeve  235 , (b) the upper arm  240 , (c) the counterweight  260 , and (d) the aircraft capturer  250  (including the fingers  255 ). 
         [0052]    In this example embodiment, the aircraft retrieval apparatus  200  is configured to measure any suitable parameters or properties of the aircraft  10  (as described above). As illustrated in  FIG. 2A , in preparation for capture, the aircraft  10  stationkeeps spanwise-to-wind relative to the surface  2000  (as described above) such that the aircraft  10  is near the apparatus  200 . As the aircraft  10  moves relative to the aircraft capturer  250 , the apparatus  200  monitors the position of the aircraft  10  relative to the aircraft capturer  250  to detect the movement of the aircraft  10  relative to the aircraft capturer  250  (as described above). The aircraft retrieval apparatus  200  (and, more specifically, the controller) automatically manipulates the sleeve  234 , the upper arm  240 , and the counterweight  260  to cause the aircraft capturer  250  to move in a manner corresponding to the movement of the aircraft such that the aircraft capturer  250  follows or tracks the movement of the aircraft  10  while maintaining a designated radial distance from the aircraft  10  (described above). 
         [0053]    As shown in  FIG. 2B , when tracking is satisfactory and the movement of the aircraft is stabilized (as described above), the apparatus  200  automatically: (a) moves the aircraft capturer  250  such that a portion of the fuselage  12  of the aircraft  10  aft of the wings  14  and near the center of mass of the aircraft  10  is positioned between the fingers  255  by axially moving or extending the upper arm  240  through the sleeve toward the aircraft  10  and axially moving the counterweight  260  along the upper arm  240  in the opposite direction (to counter-balance the extending arm); and (b) manipulates the fingers  255  into the closed configuration such the fingers  255  capture the fuselage  12  (and, therefore, the aircraft  10 ) therebetween. 
         [0054]    It should be appreciated that the fingers  255  capture the fuselage aft of the wings  14  and near the center of mass of the aircraft  10  (as described above). It should also be appreciated that after the apparatus determines that tracking is satisfactory, the apparatus captures the hovering aircraft quickly enough so that any motion between the point in time at which the decision is made to capture the hovering aircraft and capture itself is negligible (as described above). 
         [0055]    In this example embodiment, once the aircraft capturer  250  captures the aircraft  10 , the apparatus  200  constrains the azimuthal and radial components of the movement of the aircraft  10 , while the main rotor  16  of the aircraft  10  continues to spin to support the weight of the aircraft  10  and to enable the aircraft  10  to continue regulating the attitude and altitude of the aircraft  10 . The fingers  255  hold the aircraft  10  with enough force to prevent the aircraft  10  from pulling free. 
         [0056]    In this example embodiment, after the aircraft capturer  250  captures the aircraft, the apparatus  200  automatically guides the aircraft into a docking station (not shown). As illustrated in  FIGS. 2C and 2D , after capturing the aircraft  10 , the apparatus begins drawing the captured aircraft  10  toward the base  210  by axially moving or retracting the upper arm  240  through the sleeve  235  such that the captured aircraft  10  approaches the base  210  and axially moving the counterweight  260  along the upper arm  240  toward the sleeve  235  (to counter-balance the retracting arm). Once the aircraft  10  reaches the base  210 , the apparatus  200  guides the aircraft  10  into the docking station (not shown), the aircraft is shut down, and the main rotor is stopped. 
         [0057]    After any servicing is performed on the aircraft  10 , the apparatus  200  launches the aircraft  10  by substantially reversing the above-described process. More specifically, to launch the aircraft  10 : (a) the aircraft  10  re-starts its engine (as described above); (b) the apparatus  200  automatically re-captures the aircraft  10 ; (c) the aircraft pulls itself out of the docking station and stationkeeps near the surface  2000 ; and (d) when the aircraft  10  is sufficiently clear of any obstacles and is determined to be stationkeeping properly (e.g., no sag is detected in the upper arm  240 ), the apparatus  200  releases the aircraft  10  into free thrust-borne flight while quickly maneuvering away from the aircraft  10 . 
         [0058]    It should be appreciated that any suitable mechanisms may be employed to: (a) rotate and pivot the sleeve, (b) axially move the upper arm through the sleeve, (c) axially move the counterweight along the upper arm, and (d) manipulate the fingers into the open and closed configurations. It should also be appreciated that, in certain embodiments, the counterweight need not be employed. It should further be appreciated that, in other embodiments, the base or the lower arm is rotatable instead of (or in addition to) the sleeve. 
       Third Example Embodiment 
       [0059]    In this example embodiment, the apparatus of the present disclosure is configured to cause the aircraft capturer to capture a wing of the aircraft between two jaws each including two fingers and automatically draw the captured aircraft into a desired position proximate the aircraft capturer by spinning the fingers. 
         [0060]      FIGS. 3A to 3L  illustrate this example embodiment of the apparatus, which is generally indicated by numeral  300  and includes: (a) a base  310  anchored or otherwise attached to the surface  2000 ; (b) a substantially vertical lower or first arm  330  extending from the base  310 ; (c) an upper or second arm  340  rotatably connected to an upper end of the lower arm  330  such that upper arm  340  is: (i) substantially perpendicular to the lower arm  330 , and (ii) configured to rotate relative to the lower arm  330  about a substantially vertical axis through the center of the lower arm  330 ; and (d) an aircraft capturer  350  mounted to the upper arm  340  such that the aircraft capturer is configured to move axially along the upper arm  340 . 
         [0061]    The aircraft capturer  350  includes a carriage  351  that is configured to move axially along the upper arm  340 . The carriage includes two spaced-apart jaws  354  and  356 . The jaw  354  includes two fingers  355   a  and  355   b  that each extend from substantially the same origin on the carriage  351 . As best shown in  FIGS. 3C and 3D : (a) the axes through the lengths of the fingers  355   a  and  355   b  are substantially coplanar, (b) the axis through the length of the finger  355   b  is substantially parallel to a vertical plane along the axis through the length of the upper arm  340 , and (c) the axis through the length of the finger  355   a  is angled about forty-five degrees from the vertical plane along the axis through the length of the upper arm  340  (though it should be appreciated that any suitable angle may be employed). Similarly, the jaw  356  includes two fingers  357   a  and  357   b  that each extend from substantially the same origin on the carriage  351 . As best shown in  FIGS. 3C and 3D : (a) the axes through the lengths of the fingers  357   a  and  357   b  are substantially coplanar, (b) the axis through the length of the finger  357   b  is substantially parallel to the vertical plane along the axis through the length of the upper arm  340 , and (c) the axis through the length of the finger  357   a  is angled about forty-five degrees from the vertical plane along the axis through the length of the upper arm  340  (though it should be appreciated that any suitable angle may be employed). 
         [0062]    The jaws  354  and  356  have a capture configuration (as shown in  FIG. 3A ), a closed configuration (as shown in  FIGS. 3B to 3J ), and a launch configuration (as shown in  FIGS. 3K and 3L ). When in the capture configuration, the jaws (i.e., the respective planes including the axes through the fingers of the respective jaws) are approximately ninety degrees (or any other suitable angle) apart and each jaw is approximately forty-five degrees (or any other suitable angle) from the axis through the length of the upper arm  340 . When in the closed configuration, the jaws are each approximately perpendicular to the axis through the length of the upper arm  340 . When in the launch configuration, the jaw  354  is approximately parallel to the axis through the length of the upper arm  340  and the jaw  356  is approximately perpendicular to the axis through the length of the upper arm  340 . 
         [0063]    In this example embodiment, each of the fingers  355   a ,  355   b ,  357   a , and  357   b  includes: (a) a generally solid support rotatably connected to the carriage  351  such that the finger may rotate relative to the carriage  351  about an axis through the length of the finger, (b) a cushioned material at least partially surrounding the support (as described above); and (c) a protective layer or coating of relatively high-friction material (as described above) substantially covering an outer surface of the cushioned material. In this example embodiment, for each of the fingers, the support of that finger includes a motor configured to spin that support (and, therefore that finger) around the axis through the length of that finger. 
         [0064]    Although not shown, the apparatus  300  includes a controller configured to control movement of: (a) the upper arm  340 ; and (b) the aircraft capturer  350  (including the carriage  351 , the jaws  354  and  356 , and the fingers  355   a .  355   b ,  357   a , and  357   b.    
         [0065]    As illustrated in  FIG. 3A , in preparation for capture, the upper arm  340  is maneuvered (rotated) such that it is substantially normal to the direction of the wind (if any) and to the centerline of the aircraft  10 , and the jaws  354  and  356  are manipulated into the capture configuration. In this example embodiment, before and during capture, the upper arm  340  is maintained at substantially the same azimuthal position (though in other embodiments the upper arm may rotate before and/or during capture). The aircraft  10  approaches the apparatus  300  and, more specifically, the aircraft capturer  350 , downwind at walking speed while regulating its altitude relative to the altitude of the upper arm  340 . As the aircraft  10  approaches the aircraft capturer  350 , the apparatus  300  (and, more specifically, the controller) automatically moves the aircraft capturer  350  along the upper arm  340  such that its axial position relative to the upper arm  340  substantially matches that of the aircraft  10 . 
         [0066]    As shown in  FIGS. 3B ,  3 C, and  3 D, the aircraft  10  is maneuvered such that one of the wings  14  is positioned between the jaws  354  and  356 , which are then manipulated into the closed configuration such the jaws  354  and  356  capture the wing  14  (and, therefore, the aircraft  10 ) therebetween. As best shown in  FIGS. 3C and 3D , after capture, the aircraft  10  is not typically in a desired position with respect to the aircraft capturer  350 . More specifically, the aircraft  10  is not typically positioned such that: (a) a bottom edge of the captured wing  14  contacts a top surface of the carriage  351 , and (b) the fuselage  12  contacts a side surface of the carriage  351 . Thus, in this example embodiment, as shown in  FIGS. 3E and 3F , after the aircraft capturer  350  captures the aircraft  10 , the fingers  357   a .  357   b ,  355   a , and  355   b  spin (via the respective motors) such that they draw the aircraft into the desired position. More specifically, in this example embodiment: (a) the fingers  357   a  and  357   b  each spin counter-clockwise around their respective axes through their respective lengths, and (b) the fingers  355   a  and  355   b  each spin clockwise around their respective axes through their respective lengths. This spin combined with the high-friction protective coating of the fingers draws the aircraft into the desired position proximate the aircraft capturer. Specifically, as shown in  FIGS. 3G and 3H , the spinning of the fingers draws the aircraft  10 : (a) downward until the bottom edge of the captured wing  14  contacts the top surface of the carriage  351 , and (b) toward the upper arm  340  until the fuselage  12  contacts the side surface of the carriage  351 . It should be appreciated that the fingers may spin in any suitable direction about any suitable axes (based on the orientation of the fingers) to draw the aircraft into the desired position. 
         [0067]    In this example embodiment, once the aircraft capturer  350  captures the aircraft  10 , the apparatus  300  constrains the azimuthal and radial components of the movement of the aircraft  10 , while the main rotor  16  of the aircraft  10  continues to spin to support the weight of the aircraft  10  and to enable the aircraft  10  to continue regulating the altitude of the aircraft  10 . The jaws  354  and  356  hold the aircraft  10  with enough force to prevent the aircraft  10  from pulling free. 
         [0068]    As illustrated in  FIG. 3I , after drawing the aircraft  10  into the desired position proximate the aircraft capturer  350 , the apparatus  300  moves the aircraft capturer  350  along the upper arm  340  to the distal end of the upper arm  340  in preparation for docking. Though not shown, the apparatus  300  rotates the upper arm  340  to center the aircraft  10  over a docking station, at which point the altitude of the aircraft  10  is reduced, the apparatus  300  releases the aircraft  10 , and the aircraft  10  drops into the docking station. Once in the docking station, the aircraft is shut down and the main rotor is stopped. 
         [0069]    After any servicing is performed, the apparatus  300  launches of the aircraft  10  by substantially reversing the above-described process. More specifically, to launch the aircraft  10 : (a) the aircraft  10  re-starts its engine (as described above); (b) the apparatus  300  automatically re-captures the aircraft  10 ; (c) the aircraft  10  pulls itself out of the docking station and stationkeeps near the surface  2000 ; (d) the fingers  357   a ,  357   b ,  355   a , and  355   a  spin (via the motors) such that they push the aircraft  10  away from the aircraft capturer  350 ; and (e) as shown in  FIGS. 3K and 3L : (i) the jaws  354  and  356  are manipulated into the launch configuration, and (ii) the aircraft capturer moves toward the distal end of the arm  340  to push the aircraft  10  into free thrust-borne flight. The aircraft capturer and arm then quickly move away from the aircraft  10 . 
         [0070]    In certain embodiments, the apparatus is configured to vary the altitude of the upper arm. In one such embodiment, the apparatus is configured to track the altitude of the bottom edge of the wing of the aircraft and set the altitude of the upper arm to match that of the bottom edge of the wing. 
         [0071]    It should be appreciated that any suitable mechanisms may be employed to: (a) rotate the upper arm; (b) axially move the aircraft capturer along the upper arm; (c) manipulate the jaws into the capture, closed, and launch configurations; and (d) cause the fingers to rotate. 
         [0072]    In certain embodiments, the apparatus is configured to measure any suitable parameters or properties of the aircraft (as described above). In other embodiments, the apparatus monitors the position of the aircraft relative to the aircraft capturer (as described above) and automatically moves the aircraft capturer based on the monitored position of the aircraft. Put differently, in these embodiments, the aircraft capturer follows or tracks axial movement (relative to the upper arm) of the aircraft by axially sliding along the upper arm as the aircraft approaches the aircraft capturer for capture. 
       Fourth Example Embodiment 
       [0073]    In this example embodiment, the apparatus of the present disclosure is configured to cause the aircraft capturer to capture a fuselage of the aircraft between two fingers and automatically draw the captured aircraft into a desired position proximate the aircraft capturer by spinning the fingers. 
         [0074]    Turning back to the Figures,  FIGS. 4A to 4E  illustrate this example embodiment of the apparatus, which is generally indicated by numeral  400  and includes: (a) a base  410  anchored or otherwise attached to the surface  2000 ; (b) a substantially vertical lower or first arm  430  extending from the base  410 ; (c) an upper arm  440  rotatably connected to an upper end of the lower arm  430  such that upper arm  440  is: (i) substantially perpendicular to the lower arm  430 , and (ii) configured to rotate relative to the lower arm  430  about a substantially vertical axis through the center of the lower arm  430 ; (d) an aircraft capturer  450  mounted to the upper arm  440  such that the aircraft capturer is configured to move axially along the upper arm  440 ; and (e) a wing restraint  460  pivotably connected to a distal end of the upper arm  440  such that the wing restraint  460  is configured to pivot about a substantially horizontal axis through the connection to the upper arm  440 . 
         [0075]    The aircraft capturer  450  includes a carriage  451  configured to move axially along the upper arm  440 . The carriage  451  supports first finger  453  above, substantially coplanar with, and substantially parallel to the axis through the length of the upper arm  440 . The first finger  453  includes: (a) a roller motor  452  connected to the carriage  451  such that the first finger  453  may spin relative to the carriage  451  (when the roller motor  452  is operated) about an axis through the length of the roller motor  452 ; (b) a cushioned material at least partially surrounding the roller motor  452  (as described above); and (c) a protective layer or coating of high-friction material (as described above) substantially covering an outer surface of the cushioned material. The carriage  451  also supports a second finger  454  that includes: (a) a generally solid support rotatably connected to the carriage  451  such that the second finger  454  may spin relative to the carriage  451  about an axis through the length of the second finger  454 ; (b) a cushioned material at least partially surrounding the support (as described above); and (c) a protective layer or coating of high-friction material (as described above) substantially covering an outer surface of the cushioned material. 
         [0076]    In this example embodiment, the axes through the lengths of the first and second fingers  453  and  454  are substantially coplanar. The second finger  454  is offset from the first finger  453  and pivotably connected to the carriage  451  such that: (a) when the first and second fingers  453  and  454  are in a closed configuration (as shown in  FIGS. 4C to 4E ), the axes through the lengths of the first and second fingers are substantially parallel; and (b) when the first and second fingers are in an open configuration (as shown in  FIGS. 4A and 4B ), the angle formed between the axes through the lengths of the first and second fingers is sized such that the mouth of the opening formed between the fingers is about twice the diameter of the fuselage  12  of the aircraft  10  (or any other suitable angle, such as an approximately ninety degree angle or an angle greater than ninety degrees). 
         [0077]    It should be appreciated that the configuration and relative locations of the fingers are merely one of a variety of different configurations and relative locations contemplated by the present disclosure. For instance, in another embodiment, the fingers are not offset from one another. In another embodiment, the axes through the lengths of the fingers are not substantially coplanar. 
         [0078]    Although not shown, the apparatus  400  includes a controller configured to control movement of: (a) the upper arm  440 ; (b) the aircraft capturer  450  (including the carriage  451 , the roller motor  452 , and the second finger  454 ); and (c) the wing restraint  460 . 
         [0079]    As illustrated in  FIG. 4A , in preparation for capture, the upper arm  440  is maneuvered (rotated) such that it is substantially normal to the direction of the wind (if any) and to the centerline of the aircraft  10 , and the fingers  453  and  454  are manipulated into the open configuration. The aircraft  10  approaches the apparatus  400  and, more specifically, the aircraft capturer  450 , downwind at walking speed while regulating its altitude relative to the altitude of the upper arm  440 . As the aircraft  10  approaches the aircraft capturer  450 , the apparatus  400  monitors the position (e.g., the altitude, azimuthal position, and radial position) of the aircraft  10  relative to the aircraft capturer  450  and rotates the upper arm  440  and/or moves the aircraft capturer  450  to follow or track the aircraft  10 . 
         [0080]    As shown in  FIGS. 4B and 4C , when the aircraft  10  contacts one of the fingers  453  and  454 , the fingers  453  and  454  are quickly manipulated into the closed configuration and the apparatus  400  slides the aircraft capturer  450  to the distal end of the upper arm  440 , thereby capturing the fuselage  12  of the aircraft  10  (and, therefore, the aircraft  10  itself) therebetween. As best shown in  FIG. 4C , after capture, the aircraft  10  is not typically in a desired position with respect to the aircraft capturer  450 . More specifically, the aircraft  10  is not typically positioned such that the bottom edges of the wings  14  contact the fingers  453  and  454 . Thus, in this example embodiment, as shown in  FIG. 4D , after the aircraft capturer  450  captures the aircraft  10 , the roller motor  452  operates to cause the finger  453  to spin clockwise. This spin combined with the high-friction protective coating of the fingers draws the aircraft  10  into the desired position proximate the aircraft capturer  450 . Specifically, as shown in  FIG. 4E , the spinning of the fingers draws the aircraft  10  downward until the bottom edges of the wings  14  contact the fingers  453  and  454 . It should be appreciated that the fingers may spin in any suitable direction about any suitable axes (based on the orientation of the fingers) to draw the aircraft into the desired position. In another embodiment, the second finger includes a roller motor configured to cause that finger to spin. As also shown in  FIG. 4E , after drawing the aircraft  10  into the desired position proximate the aircraft capturer  450 , the apparatus  400  pivots the wing restraint  460  upward to further secure the aircraft  10 . 
         [0081]    In this example embodiment, once the aircraft capturer  450  captures the aircraft  10 , the apparatus  400  constrains the azimuthal, radial, and attitude components of the movement of the aircraft  10  while the main rotor  16  of the aircraft  10  continues to spin to substantially support the weight of the aircraft  10  and to enable the aircraft  10  to continue regulating the altitude component of the movement of the aircraft  10 . The fingers  453  and  454  hold the aircraft  10  with enough force to prevent the aircraft  10  from pulling free. 
         [0082]    Though not shown, the apparatus  400  rotates the upper arm  440  to center the aircraft  10  over a docking station, at which point the altitude of the aircraft  10  is reduced, the apparatus  400  releases the aircraft  10 , and the aircraft  10  drops into the docking station. Once in the docking station, the aircraft is shut down and the main rotor is stopped. After any servicing is performed on the aircraft  10 , the apparatus  400  launches of the aircraft  10  by substantially reversing the above-described process. More specifically, to launch the aircraft  10 : (a) the aircraft  10  re-starts its engine (as described above); (b) the apparatus  400  automatically re-captures the aircraft  10 ; (c) the aircraft  10  pulls itself out of the docking station and stationkeeps near the surface  2000 ; (d) the wing restraint  460  is pivoted downward; (e) the roller motor operates to cause the finger  453  to spin counter-clockwise, which pushes the aircraft  10  away from the aircraft capturer  450 ; and (f) when the aircraft  10  is sufficiently clear of any obstacles and is determined to be stationkeeping properly (e.g., no sag is detected in the upper arm  440 ), the apparatus  400  manipulates the fingers  453  and  454  into the open configuration to release the aircraft  10  into free thrust-borne flight while quickly maneuvering away from the aircraft  10 . 
         [0083]    In certain embodiments, the apparatus is configured to vary the altitude of the upper arm. In one such embodiment, the apparatus is configured to track the altitude of the bottom edge of the wing of the aircraft and set the altitude of the upper arm to match that of the bottom edge of the wing. 
         [0084]    It should be appreciated that any suitable mechanisms may be employed to: (a) rotate the upper arm; (b) axially move the aircraft capturer along the upper arm; (c) manipulate the fingers into the open and closed configurations; and (d) operate the roller motor. 
         [0085]    In certain embodiments, the apparatus is configured to measure any suitable parameters or properties of the aircraft (as described above). 
       VARIATIONS 
       [0086]    It should be appreciated that the apparatus may be attached to any suitable surface, such as a static surface or a moving surface. 
         [0087]    It should be appreciated that any of the joints described herein as revolute joints, ball-and-socket joints, or any other type of joint may be replaced with any other suitable type of joint to provide a different type of movement of the components of the apparatus. 
         [0088]    In various embodiments, the docking station is coupled to the apparatus, such as coupled to the base of the apparatus. In other embodiments, the docking station is coupled to a surface within reach of the apparatus, such as the surface to which the base of the apparatus is anchored. In one such example embodiment, the apparatus and the docking station form an aircraft retrieval system. 
         [0089]    In certain embodiments, as the apparatus guides the aircraft into the docking station, one or more servicing connections to automatically provide (or remove) fuel, oil, electricity, and the like to (or from) the aircraft are made. Alternatively, such connections are made after the aircraft is secured in the docking station. This enables the aircraft automatically to be serviced in preparation for launch. 
         [0090]    In certain instances, such as when the aircraft is not going to be launched for a relatively substantial period of time, after the aircraft is secured in the docking station, the apparatus releases the aircraft. The apparatus may then automatically maneuver the aircraft capturer and any other suitable components elsewhere, such as into a stowed configuration. In other instances, such as when the aircraft is going to be launched in a relatively short amount of time, the aircraft capturer continues holding the aircraft while the aircraft is being recharged and/or refueled in preparation for launch. 
         [0091]    Due to winds, the spinning of the main rotor and the thrusters, and movement of the surface to which the apparatus is attached, the aircraft is constantly moving. In certain embodiments, the apparatus does not automatically maneuver the aircraft capturer to follow the aircraft unless the movement of the aircraft relative to the aircraft capturer exceeds a designated threshold. For instance, in an embodiment in which the apparatus is configured to measure the position of the aircraft on the order of centimeters, any movements less than one centimeter will not be followed or tracked. It should be appreciated that the designated threshold may be set such that the apparatus does not maneuver the aircraft capturer to follow the aircraft unless the movement of the aircraft is more than negligible. 
         [0092]    In certain embodiments, the apparatus includes a manual override that, if activated, enables a user to manually control the movement of one, a plurality of but less than all of, or all of the components of the apparatus rather than having the apparatus automatically control the movement of some or all of the components of the apparatus. In other words, these embodiments enable a user to switch from a fully automated capture, dock, and launch cycle to one that is at least partially manual. 
         [0093]    In other embodiments, the apparatus is configured to receive measurements of one or more of the parameters of the aircraft (such as: (a) the altitude of the aircraft; (b) the azimuthal position of the aircraft; (c) the radial position of the aircraft; (d) the global position of the aircraft; (e) the components of the velocity of the aircraft; (f) the components of the velocity of the aircraft relative to any suitable point; and (g) the attitude of the aircraft) from a source external to the apparatus. For instance, in one example embodiment, the aircraft itself measures certain parameters and sends such measurements to the apparatus. 
         [0094]    It should be appreciated that, in other embodiments, the apparatus is configured to support the entire weight of the aircraft after capture and, therefore, the aircraft may shut off its rotor and power down after capture. 
         [0095]    It should be appreciated that the sizes and shapes of the various components may vary from those described herein and illustrated in the Figures. 
         [0096]    It should be appreciated that any suitable features of any of the above-described embodiments may be combined. 
         [0097]    It should be understood that various changes and modifications to the present embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.