Patent Publication Number: US-2016244160-A1

Title: Convertible unmanned aerial vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 61/864,257, filed on Aug. 9, 2013, and entitled “CONVERTIBLE AIRCRAFT,” the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present disclosure relates generally to unmanned aerial vehicles, and more particularly to unmanned aerial vehicles that can utilize any of a plurality of lift assemblies for flight. 
     An unmanned aerial vehicle (UAV) is a remotely piloted or self-piloted aircraft that can carry cameras, sensors, communications equipment, or other payloads. UAVs are often capable of controlled, sustained flight, and can be powered by, e.g., a battery, a fuel cell, a motor, an engine, or other power sources. UAVs may be remotely controlled (e.g., via joystick or other hand-actuated controller, remote computer, or other types of controllers), or may fly autonomously based on preprogrammed flight plans or complex dynamic automation systems. 
     UAVs have become increasingly utilized for various applications where the use of manned flight vehicles is not appropriate, not economical, or is not feasible. Example applications in which UAVs may typically be utilized can include surveillance, reconnaissance, target acquisition, data acquisition, communications relay, decoy, harassment, and supply flights. UAVs have also been utilized in a growing number of civilian applications, such as firefighting when a human observer would be at risk, police observation of civil disturbances or crime scenes, reconnaissance support in natural disasters, search and rescue, and scientific research, such as for collecting data from within storms (e.g., hurricanes). 
     UAVs are typically designed as either a fixed wing aircraft or a rotary wing aircraft, each having associated benefits and drawbacks. For example, fixed wing aircraft are typically capable of flying at higher airspeeds than rotary wing aircraft, but are generally incapable of hovering maneuvers as well as vertical take-offs and landings. In contrast, rotary wing aircraft are typically capable of hovering maneuvers and vertical take-offs and landings, but may be limited to lower airspeeds and shorter missions. Traditional hybrid designs typically sacrifice performance of both the fixed wing and rotary wing designs to achieve some of the advantages of both. Accordingly, where the full advantages of either the fixed wing or rotary wing design are desired, it has generally been necessary to utilize two different aircraft. 
     SUMMARY 
     In one example, an unmanned aerial vehicle includes a fuselage and a lift assembly. The lift assembly is selected from a plurality of lift assemblies, each of the plurality of lift assemblies having a different flight modality. The fuselage includes a mounting portion configured to mount with any of the plurality of lift assemblies. 
     In another example, an unmanned aerial vehicle includes a fuselage, an electrical interface, and a controller. The fuselage includes a mounting portion configured to mount with any of a plurality of lift assemblies. Each of the plurality of lift assemblies has a different flight modality and one or more flight control surfaces corresponding to the respective flight modality. The electrical interface is configured to electrically connect the fuselage and any of the plurality of lift assemblies. The electrical interface is further configured to identify the flight modality of an electrically connected one of the plurality of lift assemblies. The controller is coupled to the electrical interface, and configured to determine the flight modality of the electrically connected one of the plurality of lift assemblies based on the electrical interface. The controller is further configured to provide control signals, based on the determined flight modality, to the flight control surfaces of the electrically connected one of the plurality of lift assemblies. 
     In another example, an unmanned aerial vehicle includes an elongate body portion and a lift assembly connected to the elongate body portion via an attachment mechanism. The lift assembly is selected from a plurality of lift assemblies, each having a different flight modality. The attachment mechanism is configured to connect the elongate body portion to any of the plurality of lift assemblies. 
     In another example, an unmanned aerial vehicle system includes a fixed wing lift assembly, a rotor lift assembly, and a fuselage. The fuselage has a mounting portion configured to mount with each of the fixed wing lift assembly and the rotor lift assembly via a common attachment mechanism. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is schematic view of an example unmanned aerial vehicle system showing conversion between fixed wing and quad-rotor lift assemblies. 
         FIG. 2  is a perspective view of an unmanned aerial vehicle having a fuselage mounted with a quad-rotor lift assembly. 
         FIG. 3  is a perspective view of an unmanned aerial vehicle having a fuselage mounted with a fixed wing lift assembly. 
         FIG. 4  is a perspective view of a female component of an attachment mechanism that can be used to connect a lift assembly to a mounting portion of a fuselage. 
         FIG. 5  is a perspective view of an insert for the female component of the attachment mechanism of  FIG. 4 . 
         FIG. 6  is a perspective view of a sliding bolt attachment mechanism that can be used to connect a lift assembly to a mounting portion of a fuselage. 
         FIG. 7  is an exploded view of the sliding bolt attachment mechanism of  FIG. 6 . 
         FIG. 8  is a perspective view of the sliding bolt attachment mechanism of  FIG. 7 . 
         FIG. 9  is a perspective view of a fuselage including an electrical component configured to interface with a corresponding electrical component of any of a plurality of lift assemblies. 
         FIG. 10  is a schematic side view of an example electrical interface of  FIG. 9 . 
         FIG. 11  is a schematic side view of the example electrical interface of  FIG. 10  showing the electrical components connected. 
         FIG. 12  is a schematic side view of another example electrical interface that can connect with a lift assembly. 
         FIG. 13  is a perspective view of a mounting cavity that can receive a power source for the unmanned aerial vehicle. 
         FIG. 14  is a front view of an alternate embodiment of an unmanned aerial vehicle having a fuselage mounted with a fixed wing lift assembly. 
         FIG. 15  is a front view of an alternate embodiment of an unmanned aerial vehicle having a fuselage mounted with a single-rotor lift assembly. 
     
    
    
     While the above-identified drawings set forth multiple embodiments of the invention, other embodiments are also contemplated. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings. Like reference numerals indicate like structures throughout the drawings. 
     DETAILED DESCRIPTION 
     According to techniques of this disclosure, an unmanned aerial vehicle (UAV) can include a fuselage having a mounting portion configured to connect with any of a plurality of lift assemblies. Each of the lift assemblies can have a different flight modality. For instance, a first lift assembly can have a fixed wing flight modality, a second lift assembly can have a single-rotor flight modality, and a third lift assembly can have a quad-rotor flight modality. In some examples, the UAV can include a controller connected to an electrical interface configured to couple to each of the lift assemblies. The electrical interface can be configured to identify a flight modality of the connected lift assembly, such as via an active pin arrangement (e.g., pattern) of the electrical interface. The controller can identify the flight modality of the connected lift assembly and can provide corresponding flight control signals to control surfaces of the lift assembly to provide controlled flight of the UAV. As such, a UAV implementing techniques described herein can convert between different flight modalities (e.g., between a fixed wing flight modality and a rotary wing flight modality) to exploit advantages of a particular flight modality without requiring the purchase, storage, maintenance of or training on separate UAVs implementing the separate flight modalities. Moreover, a common controller, power source, and payload mount (e.g., each connected to or included in a common fuselage) can decrease a monetary expense of the UAV system as a whole, as well as training time and costs associated with use of the UAV system. Common attachment mechanisms can enable quick and efficient interchanges between lift systems, while automatic identification of a flight modality of a connected lift system can enhance usability of the UAV. 
       FIG. 1  is schematic view of UAV system  10  showing a conversion between fixed wing lift assembly  12  and quad-rotor lift assembly  14 . As illustrated, UAV system  10  can include fuselage  16 , fixed wing lift assembly  12 , and quad-rotor lift assembly  14 . Fuselage  16  includes mounting portion  18  and propeller  20 . While illustrated as including two lift assemblies  12  and  14 , in other examples UAV system  10  can include more than two lift assemblies, such as three or more lift assemblies. For instance, UAV system  10  can further include a single-rotor lift assembly, a dual-rotor lift assembly, or other types of lift assemblies. In addition, while illustrated as including both fixed wing lift assembly  12  having a fixed wing flight modality and quad-rotor lift assembly  14  having a quad-rotor flight modality, in some examples, UAV system  10  may not include one or more of fixed wing lift assembly  12  and quad-rotor lift assembly  14 . 
     Fixed wing lift assembly  12  includes elevons  22 A and  22 B (collectively referred to herein as “elevons  22 ”) and pitot probe  24 . Elevons  22  can be deflected up and down via actuators (not illustrated) to provide pitch control (e.g., both deflected up or both deflected down) and roll control (e.g., one deflected up and the other deflected down) during flight. As such, elevons  22  can be considered flight control surfaces that can be utilized for controlled flight, such as via actuation by a controller attached to fuselage  16  (e.g., a controller implementing autopilot functionality), as is further described below. Pitot probe  24  can include one or more pressure sensors that sense a velocity of air impacting pitot probe  24  for use in determining, e.g., airspeed. In this way, pitot probe  24  can be considered a sensor configured to sense data corresponding to flight conditions of the UAV. In some examples, UAV system  10  can include other sensors configured to sense flight condition data, such as one or more of a magnetometer, an accelerometer, a gyroscope, a global positioning system (GPS) receiver, or other sensors. 
     Quad-rotor lift assembly  14  includes rotor assemblies  26 A,  26 B,  26 C, and  26 D (collectively referred to herein as “rotor assemblies  26 ”). A rotational speed of each of rotor assemblies  26  can be controlled independently (e.g., via a controller) to provide thrust, lift, pitch, and roll control of the UAV. As such, each of rotor assemblies  26  can be considered flight control surfaces that can be utilized for controlled flight of the UAV. 
     Fuselage  16  can include propeller  20  that can be actuated (e.g., via a motor) to provide thrust for the UAV along axis  28 . As illustrated, fuselage  16  can include an elongated body portion having a major axis extending along axis  28 . In this way, fuselage  16  can be formed for aerodynamic flight along axis  28  which defines the axis of thrust provided by propeller  20 . In other examples, fuselage  16  may not include an elongated body portion. For instance, fuselage  16  can be square, circular, or other non-elongated shape. Fuselage  16  further includes mounting portion  18 . Mounting portion  18  can be configured to mount with each of fixed wing lift assembly  12  and quad-rotor lift assembly  14 , e.g., via one or more connection mechanisms, as is further described below. In the example of  FIG. 1 , mounting portion  18  is disposed at a top side of fuselage  16  (i.e., a top side with respect to an orientation of fuselage  16  during normal flight conditions). In other examples, mounting portion  18  can be disposed at other locations of fuselage  16 , such as at a bottom side or another location of fuselage  16 . In general, mounting portion  18  can be disposed at any portion(s) of fuselage  16  that enables mounting of fuselage  16  with any of a plurality of lift assemblies. 
     As illustrated in  FIG. 1 , UAV system  10  can be converted between a fixed wing flight modality and a quad-rotor flight modality. That is, each of fixed wing lift assembly  12  and quad-rotor lift assembly  14  can be removably connected to mounting portion  18  to enable conversion between the fixed wing and quad-rotor flight modalities. In general, mounting portion  18  can be configured to mount with any of a plurality of lift assemblies, such as two, three, four, or more lift assemblies, each of which configured to be removably connected to mounting portion  18  to enable conversion between the flight modalities associated with each of the plurality of lift assemblies. In this way, UAV system  10  can be configured such that flight is accomplished via any of the plurality of flight modalities, thereby enabling UAV system  10  to exploit the full advantages of any of the plurality of flight modalities. 
       FIG. 2  is a perspective view of UAV system  10  having fuselage  16  mounted with quad-rotor lift assembly  14 . As illustrated in  FIG. 2 , quad-rotor lift assembly  14  includes rotor assemblies  26 . Each of rotor assemblies  26  includes a corresponding motor that provides rotational actuation of the blades of the respective one of rotor assemblies  26 . That is, rotor assembly  26 A includes motor  30 A, rotor assembly  26 B includes motor  30 B, rotor assembly  26 C includes motor  30 C, and rotor assembly  26 D includes motor  30 D (motors  30 A,  30 B,  30 C, and  30 D are collectively referred to herein as “motors  30 ”). Quad-rotor lift assembly  14  includes mounting plate  32  which connects with mounting portion  18  of fuselage  16  via forward coupling mechanism  34  and aft coupling mechanism  36 . As illustrated, rotor assembly  14  further includes extension arms  38 A,  38 B,  38 C, and  38 D (collectively referred to herein as “extension arms  38 ”) that extend from mounting plate  32  to each of rotor assemblies  26 , respectively. That is, extension arm  38 A connects to mounting plate  32  and extends from mounting plate  32  to rotor assembly  26 A. Extension arm  38 B connects to mounting plate  32  and extends from mounting plate  32  to rotor assembly  26 B. Extension arm  38 C connects to mounting plate  32  and extends from mounting plate  32  to rotor assembly  26 C. Extension arm  38 D connects to mounting plate  32  and extends from mounting plate  32  to rotor assembly  26 D. 
     Extension arms  38  can be rigid extensions formed of lightweight material having a high tensile strength, such as aluminum, titanium, composite material (e.g., carbon fiber), or other material suitable to fixedly attach rotor assemblies  26  at a distance from fuselage  16 . In addition, extension arms  38  can include a hollow interior that provides a conduit for electrical cables from fuselage  16  to each of rotor assemblies  26 , such as electrical cables to provide power or other electrical signals to each of rotor assemblies  26 . For instance, each of motors  30  can be electrically connected, via electrical cables extending through extension arms  38 , to a controller within fuselage  16  that provides flight control signals to each of motors  30  (e.g., electrical signals to control a rotational speed of each of motors  30 ), as is further described below. In other examples, electrical cables can extend along an outer side of extension arms  38 , e.g., fixed to extension arms  38  at one or more locations to prevent excessive movement of the cables. In such examples, extension arms  38  may not be hollow. 
     As illustrated in  FIG. 2 , mounting plate  32  connects to mounting portion  18  of fuselage  16  via forward coupling mechanism  34  and aft coupling mechanism  36 . Forward coupling mechanism  34  can include, as in the example of  FIG. 2 , a female mating component, such as an arcuate recess configured to receive a corresponding male mating component of mounting plate  32 . Aft coupling mechanism  36 , in the example of  FIG. 2 , includes a plurality of sliding bolt connectors configured to connect to corresponding recesses in an aft portion of fuselage  16 , as is further described below. Forward coupling mechanism  34  and aft coupling mechanism  36  secure mounting plate  32  to fuselage  16  at mounting portion  18 , thereby securing lift assembly  14  to fuselage  16  for controlled flight of the UAV. Forward coupling mechanism  34  and aft coupling mechanism  36  are only two examples of attachment mechanisms that can be used to secure lift assembly  14  to fuselage  16 , and other example attachment mechanisms are contemplated. For instance, one or more of forward coupling mechanism  34  and aft coupling mechanism  36  can be bolted connections, cam connections, interference fit connections, or other connections configured to secure mounting plate  32  to fuselage  16 . In some examples, mounting plate  32  can be secured to fuselage  16  via greater or fewer coupling mechanisms than the two coupling mechanisms illustrated in the example of  FIG. 2  (e.g., one, three, four, or more coupling mechanisms). In general, mounting portion  18  can include any number of coupling mechanisms sufficient to secure any of a plurality of lift assemblies to fuselage  16 . 
     As further illustrated in  FIG. 2 , fuselage  16  can be connected to propeller  20  that is configured to provide thrust along axis  28  during flight. In some examples, propeller  20  can be actuated (i.e., rotated) to provide thrust along axis  28  during flight via the quad-rotor flight modality provided by quad-rotor lift assembly  14 . For instance, each of rotor assemblies  26  can be controlled (e.g., via a controller device) to provide lift, thrust, pitch, and roll control of the UAV during flight. In some examples, propeller  20  can be actuated (i.e., in addition to each of rotor assemblies  26 ) to provide additional thrust along axis  28  during flight. In other examples, propeller  20  may not be actuated during flight via a rotary wing flight modality (e.g., a single rotor flight modality, a dual rotor flight modality, a tri-rotor flight modality, a quad-rotor flight modality, or other rotary wing flight modality). Propeller  20  can be formed of plastic, fiberglass, composite material (e.g., carbon fiber), metal (e.g., aluminum, titanium, etc.), or other material having a stiffness sufficient to enable propeller  20  to provide thrust via rotation. In some examples, such as the example of  FIG. 2 , propeller  20  can be hinged to enable each of the propeller blades to be folded against fuselage  16  (e.g., a retracted position), thereby removing aerodynamic drag resulting from the propeller blades when they are not being actuated. In certain examples, such as when propeller  20  is formed of a resilient material such as plastic, propeller  20  may not be hinged, but may be folded against fuselage  16  into the retracted position without the use of a hinge. In some examples, fuselage  16  can include a recess configured to accept propeller  20  when propeller  20  is in the retracted position, thereby further reducing aerodynamic drag caused by propeller  20  when it is not being actuated. In certain examples, fuselage  16  can include one or more retention mechanisms, such as a strap, snap, or other retention mechanism to secure the blades of propeller  20  in the retracted position. 
       FIG. 3  is a perspective view of UAV system  10  having fuselage  16  mounted with fixed wing lift assembly  12 . As illustrated in  FIG. 3 , fixed wing lift assembly  12  can include starboard wing portion  40 A and port wing portion  40 B (collectively referred to herein as “wing portions  40 ”). Wing portions  40  can be separable but complementary wing portions that, when connected, form a unified flight surface (i.e., airfoil) to provide lift and enable controlled flight of the UAV. In some examples, fixed wing lift assembly  12  can include more than the two wing portions  40  illustrated in the example of  FIG. 3 , such as three or more complementary wing portions that assemble to provide a unified flight surface. In other examples, fixed wing lift assembly  12  can include a single wing portion that provides a unified flight surface. For instance, wing portions  40 A and  40 B may not be separable, but may form a single, unified flight surface configured to attach to mounting portion  18  of fuselage  16 . 
     As illustrated in  FIG. 3 , fixed wing lift assembly  12  connects to mounting portion  18  via forward coupling mechanism  34  and aft coupling mechanism  36 . As illustrated by like numerals, forward coupling mechanism  34  and aft coupling mechanism  36  can be common to the coupling mechanisms utilized by UAV system  10  to connect quad-rotor lift assembly  14  to mounting portion  18 . As such, mounting portion  18  can include one or more attachment mechanisms that enable connection of any of a plurality of lift assemblies via the attachment mechanisms. In this way, mounting portion  18  can include one or more attachment mechanisms that are configured to be common between each of the plurality of lift assemblies, thereby facilitating ease of attachment, detachment, and interchangeability of each of the plurality of lift assemblies. 
       FIG. 4  is a perspective view of female component  42  of forward coupling mechanism  34  that can be configured to connect with a corresponding male component to connect a lift assembly to mounting portion  18  of fuselage  16 . As illustrated in  FIG. 4 , female component  42  connects to (or extends from) mounting portion  18 . Female component  42  can be formed of a single piece of material, such as a lightweight material having high tensile strength (e.g., aluminum, titanium, composite material such as carbon fiber, or other material). In other examples, female component  42  can be formed of multiple (e.g., two, three, or more) pieces configured to be assembled to form a mounting configuration of female component  42  that is configured to receive a corresponding male component for mounting any one of a plurality of lift assemblies to mounting portion  18 . 
     Female component  42  can be formed to include first sidewall portion  44 A and second sidewall portion  44 B (collectively referred to herein as “sidewall portions  44 ”). As illustrated, sidewall portions  44  can be angled to intersect at an obtuse angle. In other examples, sidewall portions  44  can intersect at a different angle, such as an acute angle. In yet other examples, sidewall portions  44  can intersect to form a rounded, flat, or other blunt-nosed intersection. 
     As further illustrated in  FIG. 4 , forward coupling mechanism  34  can include mating insert  46 . Mating insert  46  can be formed to include an outer surface complementary to an inner surface of female component  42 , thereby enabling insertion of mating insert  46  into female mating component  42 . Mating inert  46 , as illustrated, can include angled inner surfaces that extend within female mating component  42  to form an arcuate recess, as is further described below. In some examples, mating insert  46  can be removable from female component  42 . In other examples, mating insert  46  can be integrally formed within female component  42 , such that mating insert  46  is not removable from female component  42 . In yet other examples, female component  42  may not include mating insert  46 . Mating insert  46  can be formed of plastic, metal (e.g., aluminum, titanium, etc.), composite material, or other material having hardness sufficient to allow removable attachment of a complementary male component with mating insert  46  without deformation of mating insert  46 . 
     While illustrated and described as including female component  42  attached to or extending from fuselage  16 , in other examples, female mating component  42  can be attached to a lift assembly. In such examples, mounting portion  18  can include a male mating component corresponding to female mating component  42 . In general, female component  42  and the corresponding male mating component can be disposed at either of fuselage  16  or a lift assembly, such that each of fuselage  16  and the lift assembly include one of female mating component  42  and the corresponding male mating component. 
       FIG. 5  is a perspective view of mating insert  46  of  FIG. 4 . As illustrated in  FIG. 5 , mating insert  46  can be formed to include outer surface  48  and inner surface  50 . Outer surface  48  can be formed to be inserted within female component  42  (illustrated in  FIG. 4 ), such that outer surface  48  contacts an inner surface of female component  42  along an entirety of outer surface  48 . In other examples, outer surface  48  can be formed to be inserted within female component  42 , such that outer surface  48  contacts an inner surface of female component  42  along a portion of outer surface  48  sufficient to prevent movement of mating insert  46  within female component  42 , but not along the entirety of outer surface  48 . In general, outer surface  48  can be formed to have a shape that is complementary to a shape of an inner surface of female component  42  to enable insertion of mating insert  46  within female component  42  such that mating insert  46  is secured within female component  42  when a lift assembly is mounted to mounting portion  18 . 
     Inner surface  50  of mating insert  46  can be formed to receive a corresponding male component of forward coupling mechanism  34 . For instance, as illustrated in  FIG. 5 , inner surface  50  can include angled inner walls that intersect at an obtuse angle to receive a complementary, e.g., pointed, male mating component. In some examples, inner surface  50  can be formed to complement a male mating component of a specific lift assembly, thereby enabling multiple mating inserts  46  to be utilized for mating each of a plurality of lift assemblies with forward coupling mechanism  34 . For instance, outer surface  48  of a first mating insert  46  can be formed to complement an inner surface of female component  42 , and inner surface  50  of the first mating insert  46  can be formed to complement a male mating component of a fixed wing lift assembly (e.g., fixed wing lift assembly  12 ). Similarly, outer surface  48  of a second, different mating insert  46  can be formed to complement an inner surface of female component  42 , and inner surface  50  of the second mating insert  46  can be formed to complement a male mating component of a rotary wing lift assembly, such as quad-rotor lift assembly  14 . In this way, female component  42  can be a common portion of forward coupling mechanism  34 , and one or more mating inserts  46  can be configured to enable mating of female component  42  with any of a plurality of different male components. 
       FIG. 6  is a perspective view of aft coupling mechanism  36  of  FIG. 4 . Aft coupling mechanism  36  can include sliding bolt attachment mechanisms  52 A and  52 B (collectively referred to herein as “sliding bolt attachment mechanisms  52 ”). As illustrated in  FIG. 6 , sliding bolt attachment mechanism  52 A can include knob  54 A. Sliding bolt attachment mechanism  52 B can include knob  54 B (knobs  54 A and  54 B are collectively referred to herein as “knobs  54 ”). Sliding bolt attachment mechanisms  52  can be configured to releasably connect a lift assembly to an aft portion of mounting portion  18 . For instance, in the example of  FIG. 6 , knobs  54  are configured to be movable in the direction indicated by arrow  56  to a disengagement position to release an engagement bolt that is configured to engage a corresponding pocket within fuselage  16  that secures mounting plate  32  to mounting portion  18 , as is further described below. Knobs  54  can be biased (e.g., spring-biased) to an engagement position, such that knobs  54  return to the engagement position when sufficient force is not applied to overcome the bias. 
     While illustrated in the example of  FIG. 6  as securing mounting plate  32  of quad-rotor lift assembly  14  to mounting portion  18 , aft coupling mechanism (including, e.g., sliding bolt attachment mechanisms  52 ) can secure any of a plurality of lift assemblies to mounting portion  18 , such as fixed wing lift assembly  12 . For instance, sliding bolt attachment mechanism  52 A can secure wing portion  40 A (illustrated in  FIG. 3 ) to mounting portion  18 , and sliding bolt attachment mechanism  52 B can secure wing portion  40 B (illustrated in  FIG. 3 ) to mounting portion  18 . In some examples, aft coupling mechanism  36  can include a single sliding bolt attachment mechanism (e.g., a single one of sliding bolt attachment mechanisms  52 ) that is configured to secure a lift assembly to mounting portion  18 . In other examples, sliding bolt attachment mechanisms  52  can take the form of other connection mechanisms, such as cam connection(s), interference fit connection(s), or one or more other fastening mechanisms configured to secure mounting plate  32  to mounting portion  18 . In general, aft coupling mechanism  36  can include any one or more connection mechanisms that can removably connect any of a plurality of lift assemblies to mounting portion  18 . 
       FIG. 7  is an exploded view of sliding bolt attachment mechanism  52 A of  FIG. 6 . While illustrated and described with respect to sliding bolt attachment mechanism  52 A, the illustration and associated description of  FIG. 7  can also be applicable to sliding bolt attachment mechanism  52 B. 
     As illustrated in  FIG. 7 , sliding bolt attachment mechanism  52 A includes knob  54 A, housing  58  extending from open end  60  to closed end  62 , bolt  64 , spring  66 , and fastener  68 . Bolt  64  includes bore  70  and engagement portion  72 . Bolt  64  is configured to be inserted within housing  58  through open end  60  and to slide within housing  58  between an engagement position and a disengagement position, as is further described below. Spring  62  is configured to be disposed between bolt  64  and closed end  62  of housing  58 . When assembled, spring  62  urges bolt  64  in a direction from closed end  62  to open end  60 , thereby biasing bolt  64  into an engagement position. As illustrated, knob  54 A is configured to be positioned atop housing  58 . Fastener  68 , which can be a bolt, screw, rivet, or other fastening device, is configured to be inserted through bore  74  of knob  54 A to engage bore  70  (e.g., a threaded bore) and thereby secure knob  54 A to bolt  64 . Knob  54 A is configured to be movable along an axis of housing  58  that extends between open side  60  and closed side  62 . 
     Bolt  64  further includes engagement portion  72  that can be configured to engage a corresponding recess in fuselage  16  when bolt  64  is in the engagement position. As illustrated in  FIG. 7 , engagement portion  72  can be a beveled tab. In other examples, engagement portion  72  can be a post, bolt, or other protrusion that extends from bolt  64  to engage a corresponding recess within fuselage  16  when bolt  64  is in the engagement position. 
     In operation, when force is applied to knob  54 A in a direction toward closed side  62  with magnitude sufficient to overcome a spring constant of spring  66 , knob  54 A and bolt  64  (via the connection of fastener  68  to bore  70 ) move in a direction toward closed side  62 . In this way, bolt  64  can be moved to a disengagement position in which engagement portion  72  disengages from the corresponding recess in fuselage  16  to disengage sliding bolt attachment mechanism  52 A from fuselage  16 . When force is no longer applied to knob  52 A with sufficient magnitude to overcome the spring constant of spring  66 , spring  66  urges bolt  64  in a direction toward open end  60  to the engagement position in which engagement portion  72  can engage the corresponding recess in fuselage  16 . In this way, sliding bolt attachment mechanism  52 A can enable tool-less connection and disconnection of a lift assembly with mounting portion  18  of fuselage  16 . In addition, beveled edges of engagement portion  72  can enable engagement portion  72  to disengage from the corresponding recess within fuselage  16  when sufficient force is applied in a direction orthogonal to the axis extending between open end  60  and closed end  62  of housing  58 . In this way, sliding bolt attachment mechanism  52 A can enable a connected lift assembly to self-disassemble upon a hard impact with, e.g., the ground, thereby dissipating the impact force and helping to prevent and/or reduce damage to components of the UAV (e.g., damage to the connected lift assembly). Moreover, knob  54 A, as illustrated, can be both ergonomic for typical manipulation by human fingers and aerodynamic to reduce drag during flight. 
       FIG. 8  is a perspective view of sliding bolt attachment mechanism  52 A as described above with respect to  FIG. 7 .  FIG. 8  illustrates sliding bolt attachment mechanism  52 A in an assembled state with bolt  64  in the engagement position. As illustrated in  FIG. 8 , bolt  64  is inserted within housing  58 . Fastener  68  is inserted through bore  74  of knob  54 A to engage bore  70  and connect bolt  64  to knob  54 A. In the illustrated example, spring  66  urges bolt  64  into the engagement position such that engagement portion  72  of bolt  64  extends from housing  58  to engage a corresponding recess within fuselage  16  (not illustrated). In operation, movement of knob  54 A toward closed end  62  of housing  58  (e.g., via finger actuation) slides bolt  64  within housing  58  toward closed end  62  until engagement portion  72  is in the disengagement position (e.g., until engagement portion  72  no longer extends from housing  58 ). Releasing pressure from knob  54 A allows spring  66  to urge bolt  64  away from closed end  62  until engagement portion  72  is in the engagement position (e.g., until engagement portion  72  extends from housing  58  to engage a corresponding recess within fuselage  16 ). 
       FIG. 9  is a perspective view of fuselage  16  including mounting portion  18  having electrical component  76  that is configured to interface with a corresponding component of any of a plurality of lift assemblies. As illustrated in  FIG. 9 , fuselage  16  can further include controller  78 , payload electrical interface  80 , payload attachment interface  82 , and motor  84 . Electrical component  76  can be configured to interface with a corresponding electrical component of any of a plurality of lift assemblies, such as via a plurality of electrical pins and pads disposed at the electrical components, as is further described below. Electrical component  76  and the corresponding electrical component of a connected lift assembly can form an electrical interface that can identify the flight modality of the connected lift assembly, such as via an active pin arrangement of the electrical interface. 
     While the example of  FIG. 9  is described with respect to an electrical interface (i.e., including electrical component  76 ) that can identify a flight modality of a connected lift assembly via an active pin arrangement, aspects of this disclosure are not so limited. For instance, controller  78  can identify a flight modality of a connected lift assembly via a wired or wireless connection, or both. As an example, each of controller  78  and the plurality of lift assemblies can include communications circuitry and/or a wireless transmitter (or transceiver), such as a Bluetooth transceiver, a cellular network transceiver, a WiFi transceiver, an optical transceiver (e.g., an infrared transceiver), a radio frequency transceiver, or other type of transmitter and/or transceiver. In certain examples, controller  78  can interrogate the communications circuitry of the lift assembly via the wireless communications connection to determine the flight modality of a connected lift assembly. In other examples, the communications circuitry of the lift assembly can broadcast an indication of the flight modality of the lift assembly, which can be received and identified by controller  78 . In one example, controller  78  can include and/or be connected to a radio frequency identification (RFID) reader, and a lift assembly can include and/or be connected to an RFID tag configured to transmit an indication of the flight modality of the lift assembly. In such an example, the RFID reader connected to controller  78  can interrogate the RFID tag to receive the indication of the flight modality of the lift assembly. 
     As in the example of  FIG. 9 , controller  78  can be electrically connected to electrical component  76  and payload electrical interface  80 . In some examples, controller  78  can be electrically connected to one or more components of a connected lift assembly via the electrical connection of electrical component  76  and the corresponding electrical component of the connected lift assembly. For instance, controller  78  can be electrically connected to motors  30  of quad-rotor lift assembly  14  (illustrated in  FIG. 2 ) via the electrical interface. As another example, controller  78  can be electrically connected to one or more actuators of fixed wing lift assembly  12  that actuate elevons  22  (illustrated in  FIG. 1 ). 
     Controller  78  can include processing circuitry configured to implement functionality and/or process instructions for execution within controller  78 . For example, controller  78  can include and/or be coupled to one or more computer-readable storage devices, such as random access memories (RAM), dynamic random access memories (DRAM), static random access memories (SRAM), flash memories, forms of electrically programmable memories (EPROM) or electrically erasable and programmable memories (EEPROM), or other forms of volatile and/or non-volatile memories. The one or more storage devices can include computer-readable instructions which, when executed by controller  78 , cause controller  78  to operate in accordance with the techniques described herein. Example processing circuitry included in controller  78  can include, but is not limited to, one or more of a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other equivalent discrete or integrated logic circuitry. 
     Controller  78  can be configured to identify the flight modality of a connected one of a plurality of lift assemblies via the electrical interface with electrical component  76 . For instance, as is further described below, controller  78  can determine a flight modality of a connected lift assembly based on an active pin arrangement of the electrical interface. Controller  78  can be configured to provide outputs to one or more flight controls of the connected lift assembly based on the determined flight modality. For example, controller  78  can determine that a connected lift assembly has a fixed wing flight modality (e.g., fixed wing lift assembly  12 ). In response, controller  78  can output flight control signals (e.g., via the connection through the electrical interface with electrical component  76  and the corresponding electrical component of the connected lift assembly) to cause elevons (e.g., elevons  22 ) of the fixed wing lift assembly to control pitch and roll of the UAV. As another example, controller  78  can determine that a connected lift assembly has a quad-rotor flight modality (e.g., quad-rotor lift assembly  14 ). In response, controller  78  can output flight control signals to cause motors (e.g., motors  30 ) of the quad-rotor lift assembly to actuate the rotors to control thrust, lift, pitch, and roll of the UAV. In general, controller  78  can be configured to output flight control signals to control flight of the UAV via the connected lift assembly based on the determined flight modality of the connected lift assembly. 
     In some examples, controller  78  can implement autopilot functionality to enable autonomous control of the UAV based on feedback from one or more sensors configured to sense data corresponding to flight conditions of the unmanned aerial vehicle (e.g., pitot probe  24 , accelerometer(s), gyroscope(s), magnetometer(s), or other sensors). In certain examples, controller  78  can select and/or modify one or more parameters of the control law(s) within the autopilot based on the determined flight modality, such as one or more gains, lag constants, rate limiters, or other parameters of the control law(s). In some examples, controller  78  can select, from a set of control laws, one or more active control laws based on the determined flight modality. For instance, controller  78  can select one or more first control laws configured to provide, e.g., pitch control for the UAV via elevons as active control laws based on a determination that a flight modality of a connected flight assembly is a fixed wing flight modality. As another example, controller  78  can select one or more second control laws configured to provide, e.g., pitch control for the UAV via a quad-rotor assembly as active control laws based on a determination that a flight modality of a connected flight assembly is a quad-rotor flight modality. As such, controller  78  can be configured to implement an autopilot that autonomously controls flight of the UAV via any of a plurality of flight modalities corresponding to the flight modalities of a plurality of lift assemblies. 
     While the example of  FIG. 9  illustrates controller  78  as included in fuselage  16 , in other examples, controller  78  can be included within the connected lift assembly. For instance, each lift assembly from the plurality of lift assemblies can include a controller (e.g., controller  78 ) configured to connect to a power source (e.g., a power source included in fuselage  16 , or a power source included in the lift assembly) and to provide flight control signals to the flight control surfaces of the lift assembly for controlled flight of the UAV. In some examples, each of fuselage  16  and a lift assembly can include a controller, with functionality attributed to controller  78  distributed among the controllers. 
     As further illustrated in  FIG. 9 , controller  78  can be electrically connected to payload electrical interface  80 . Payload electrical interface  80  can be configured to connect with a payload, such as camera(s), sensor(s) (e.g., pressure sensors, temperature sensors, image sensors, moisture sensors, altimeters, and the like), communications equipment, or other payloads. Such payloads can be configured to be interchangeably connected to fuselage  16  via payload attachment interface  82 , which can be a common attachment interface configured to connect with any of a plurality of payloads. In certain examples, payload electrical interface  80  can be configured to identify a type of a connected payload (e.g., a sensor type of the connected payload). For instance, payload electrical interface  80  can be substantially similar to electrical component  76 , such that controller  78  can identify a type of a connected one of a plurality of payloads via electrical interface  80  (e.g., an active pin arrangement of electrical interface  80 ). In some examples, controller  78  can identify a type of a connected payload via wireless communications, such as via Bluetooth, WiFi, RFID, or other wireless communications. 
     Motor  84 , in some examples, can be electrically connected to controller  78 , which can provide control signals to control operation of the motor for actuation of, e.g., propeller  20 . Examples of motor  84  can include electric motors, combustion motors (e.g., gas motors), or other types of motors. 
       FIG. 10  is a schematic side view of one example of electrical interface  86  including electrical components  76  and  88 . As illustrated in  FIG. 10 , electrical interface  86  can further include alignment posts  90 A and  90 B (collectively referred to herein as “alignment posts  90 ”), bores  92 A and  92 B (collectively referred to herein as “bores  92 ”), and canted springs  94 A and  94 B (collectively referred to herein as “canted springs  94 ”). As further illustrated, electrical component  76  can, in one example, include a plurality of electrical pads  96 . Electrical component  88  can include, in one example, a plurality of electrical pins  98 . As in the example of  FIG. 10 , electrical component  88  can be disposed at a lift assembly (e.g., fixed wing lift assembly  12 , quad-rotor lift assembly  14 , or other lift assemblies). Electrical component  76  can be disposed at mounting portion  18  of fuselage  16 . While the example of  FIG. 10  illustrates electrical component  88  as including electrical pins  98  and electrical component  76  as including electrical pads  96 , in other examples, electrical component  88  can include electrical pads  96  and electrical component  76  can include electrical pins  98 , as is further described below. 
     Electrical pads  96  can be electrically connected to controller  78  (illustrated in  FIG. 9 ). Electrical pads  96  can be disposed to interface with electrical pins  98 , such that each of electrical pins  98  aligns with one of electrical pads  96  when electrical component  88  is mated with electrical component  76 . One or more of electrical pins  98  can be retractable electrical pins. As such, one or more of electrical pins  98  can be retracted such that the retracted pin does not contact the corresponding one of electrical pads  96  when electrical component  88  is mated with electrical component  76 . The arrangement of electrical pins  98  that are configured to contact electrical pads  96  when electrical component  88  is mated with electrical component  76  can be considered an active pin arrangement of electrical interface  86 . The active pin arrangement can identify a flight modality of a connected lift assembly. For instance, a first lift assembly (e.g., fixed wing lift assembly  12 ) can correspond to an active pin arrangement in which each of electrical pins  98  contacts a corresponding one of electrical pads  96 , and a second lift assembly (e.g., quad-rotor lift assembly  14 ) can correspond to an active pin arrangement in which all but one of electrical pins  98  contacts a corresponding one of electrical pads  96 . In this way, an active pin arrangement of electrical interface  86  can identify a flight modality of a connected one of a plurality of lift assemblies. Controller  78  can determine, based on determining the active pin arrangement, the flight modality of a connected one of a plurality of lift assemblies. 
     As illustrated in  FIG. 10 , each of bores  92  can be configured to receive one of alignment posts  90 . Alignment posts  90  and bores  92  can be arranged to align electrical pins  98  and electrical pads  96  when electrical component  88  is mated with electrical component  76 , thereby enabling blind mating of electrical components  88  and  76 . Canted springs  94  are configured to retain alignment posts  90  when electrical component  88  is mated with electrical component  76 . In some examples, electrical interface  86  may not include canted springs  94 , but may retain alignment posts  90  within bores  92  using an interference fit or other retaining mechanism. In other examples, bores  92  may be configured to receive alignment posts  90  but not retain alignment posts  90  when electrical component  88  is mated with electrical component  76 . In some examples, electrical interface  86  can include greater or fewer than the two alignment posts  90  illustrated in  FIG. 10 , such as one, three, or more alignment posts  90 . 
       FIG. 11  is a schematic side view of the example of electrical interface  86  of  FIG. 10  showing electrical component  88  mated with electrical component  76 . In the illustrated example of  FIG. 11 , each of alignment posts  90  is inserted within a corresponding one of bores  92 . Canted springs  94  rest within beveled portions of guide posts  90  to retain guide posts  90  within bores  92 . The arrangement of alignment posts  90  and bores  94  aligns electrical pins  98  of electrical component  88  with electrical pads  96  of electrical component  76  such that electrical pins  98  contact electrical pads  96 . As illustrated in  FIG. 11 , canted springs  94  are configured to fit within recessed portions of guide posts  94  to retain alignment posts  90  and maintain electrical pins  98  in a compressed and connected configuration with electrical pads  96  when electrical component  88  is mated with electrical component  76 . 
       FIG. 12  is a schematic side view of another example of electrical interface  86 . As illustrated in  FIG. 12 , electrical interface  86  can include guide posts  90  configured to be received by bores  92  and retained by canted springs  94 . In this example, electrical interface  86  includes electrical component  88 ′ and electrical component  76 ′. Electrical component  88 ′ includes electrical pads  96 ′ disposed at opposite ends of electrical component  88 ′. Electrical component  76 ′ includes electrical pins  98 ′ arranged to align with electrical pads  96 ′ when electrical component  88 ′ is mated with electrical component  76 ′. 
       FIG. 13  is a perspective view of a bottom side of fuselage  16  including power source mounting cavity  100  that is configured to receive a power source that supplies power to components of the UAV. As illustrated in  FIG. 13 , power source mounting cavity  100  can include power source connection  102 . Power source mounting cavity  100  can be configured to receive a power source, such as a battery, a fuel cell, a motor, an engine, or other power source. Power source connection  102  can be an electrical connection configured to mate with a corresponding electrical connection of a power source, such as a corresponding electrical connection of a battery. Power source connection  102  can be electrically connected to components of the UAV to supply electrical power from a connected power source to components of the UAV, such as motors, actuators, controllers, or other electrical components of the UAV. In some examples, power source mounting cavity  100  and power source connection  102  can be configured to interchangeably receive any of a plurality of power sources, such as any of a battery, a fuel cell, a generator, or other power source. 
       FIG. 14  is a front view of an alternate embodiment of fuselage  16  coupled to fixed wing lift assembly  104  via attachment mechanisms  106 A and  106 B.  FIG. 14  illustrates another embodiment of attachment mechanisms that can be utilized to connect any of a plurality of lift assemblies to fuselage  16 . In the example of  FIG. 14 , fixed wind lift assembly  104  includes wing portion  108  and extension arms  110 A and  110 B (collectively referred to herein as “extension arms  110 ”). Extension arms  110 , which can be formed of any lightweight material having high tensile strength (e.g., aluminum, titanium, carbon fiber composite, or other materials), extend from an underside of wing portion  108  toward port and starboard sides of fuselage  16 , respectively. Extension arms  110  connect to fuselage  16  via attachment mechanisms  106 A and  106 B (collectively referred to herein as “attachment mechanisms  106 ”). Examples of attachment mechanisms  106  can include bolted connections, cam connections, interference fit connections, or other attachment mechanisms capable of securing extension arms  110  to fuselage  16 . 
       FIG. 15  is a front view of an alternate embodiment of fuselage  16  coupled to single-rotor lift assembly  112  via attachment mechanisms  106 . As illustrated, single-rotor lift assembly  112  can include rotor  114  that connects to mounting plate  116 . Extension arms  118 A and  118 B (collectively referred to herein as “extension arms  118 ”) extend from mounting plate  116  toward port and starboard sides of fuselage  16 , respectively. Extension arms  118  connect to fuselage  16  via attachment mechanisms  106 . Accordingly, attachment mechanisms  106  can be considered attachment mechanisms that are configured to mount with any of a plurality of lift assemblies. 
     While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.