Patent Description:
An unmanned vehicle, which may also be referred to as an autonomous vehicle, is a vehicle capable of travel without a physically-present human operator. An unmanned vehicle may operate in a remote-control mode, in an autonomous mode, or in a partially autonomous mode.

When an unmanned vehicle operates in a remote-control mode, a pilot or driver that is at a remote location can control the unmanned vehicle via commands that are sent to the unmanned vehicle via a wireless link. When the unmanned vehicle operates in autonomous mode, the unmanned vehicle typically moves based on pre-programmed navigation waypoints, dynamic automation systems, or a combination of these. Further, some unmanned vehicles can operate in both a remote-control mode and an autonomous mode, and in some instances may do so simultaneously. For instance, a remote pilot or driver may wish to leave navigation to an autonomous system while manually performing another task, such as operating a mechanical system for picking up objects, as an example.

Various types of unmanned vehicles exist for various different environments. For instance, unmanned vehicles exist for operation in the air, on the ground, underwater, and in space. Examples include quad-copters and tail-sitter UAVs, among others. Unmanned vehicles also exist for hybrid operations in which multi-environment operation is possible. Examples of hybrid unmanned vehicles include an amphibious craft that is capable of operation on land as well as on water or a floatplane that is capable of landing on water as well as on land.

UAVs may be used to deliver a payload to, or retrieve a payload from, an individual or business. <CIT> describes a payload coupling apparatus. A payload may be automatically retrieved by lowering a payload coupling apparatus and automatically retrieving the payload from a payload retrieval apparatus. For example, the payload may have a handle that may be secured to a payload coupling apparatus at the end of the winch, or a handle that may be secured within the UAV. During automatic retrieval, the payload coupling apparatus may have a hook or lip beneath a slot, the hook or lip or the payload coupling apparatus may be extended through an aperture in the handle of the payload to secure the payload to the payload coupling apparatus.

The payload coupling apparatus may provide for automated delivery of the payload as well. Upon arriving at a payload delivery site, the payload coupling apparatus and attached payload may be lowered by a winch within the UAV and the payload may land on the ground or payload receiving apparatus. Once the payload contacts the ground or payload receiving apparatus, the payload coupling apparatus may be further lowered by the winch and automatically disengage from the handle of the payload. Once the payload coupling apparatus is disengaged from the payload, the UAV may move into forward flight to another payload retrieval site or charging station, with the payload coupling apparatus suspended from the UAV at the end of the winch line. As the UAV moves forward, the payload coupling apparatus may be winched back towards the UAV. However, forward movement and retraction of the UAV may result in undesirable oscillations and instability in the payload coupling apparatus causing the payload coupling apparatus to move wildly where it may contact the UAV during flight. As a result, the speed at which the UAV may move forward during payload coupling apparatus retraction may need to be reduced.

Therefore, it would be desirable to provide a payload coupling apparatus that allows for stable retraction of the payload coupling apparatus through a wide range of air speeds, and at a full cruise speed of <NUM>-<NUM>/s, or more.

A payload coupling apparatus according to claim <NUM> and a method of retracting a payload coupling apparatus to a UAV according to claim <NUM> are provided. The present embodiments advantageously provide a payload coupling apparatus that has the same hook and lip construction as a smooth-walled payload coupling apparatus, but advantageously includes a series of perforations or holes in the major surfaces of the payload coupling apparatus which allow the payload coupling apparatus to remain stable even at increased air speeds of <NUM>-<NUM>/s or more. The series of perforations or holes serve to stabilize the payload coupling apparatus so that it remains in a relatively stable state during high speed UAV flight of <NUM>-<NUM>/s or more.

A series of holes or elongated holes (hereafter "holes") are positioned on the major surfaces of the payload coupling apparatus. In particular, the payload coupling apparatus may have a hemispherically-shaped upper portion where a tether may be attached, or extend through for internal attachment, at a centrally located point. A series of holes are positioned on the hemispherically-shaped upper portion, which may have an equal spacing therebetween. A side wall of the payload coupling apparatus beneath the hemispherically-shaped upper surface may also be provided with holes, and cams on the side walls also may include holes therein.

Similarly, the hook or lip of the payload coupling apparatus has holes positioned therein that extend from the slot through the upper and lower surfaces of the hook or lip. In addition, an upper surface of the slot includes one or more holes therein that extend from the slot into an interior of the payload coupling apparatus.

The holes extend through outer surfaces of the payload coupling apparatus into a hollow interior of the payload coupling apparatus. As a result, air is allowed to flow through the payload coupling apparatus, i.e. through the holes on the hemispherically-shaped upper portion and through the holes in the upper and lower surfaces of the slot and hook or lip, during high speed flight which allows for the payload coupling apparatus to remain in a stable position during retraction as the UAV moves at full cruise speed of <NUM>-<NUM>/s or more.

In one aspect, a payload coupling apparatus is provided that includes a housing having an upper portion, a lower portion, and a side wall positioned between the upper and lower portions, an attachment point on the housing adapted for attachment to a first end of a tether, a slot in the housing that extends downwardly towards a center of the housing thereby forming a hook or lip on the lower portion of the housing beneath the slot, a plurality of holes in the upper portion of the housing; and a plurality of holes in the lower portion of the housing.

In another aspect, a method of retracting a payload coupling apparatus to a UAV is provided including (i) providing the payload coupling apparatus with a housing having an upper portion and a lower portion, and a side wall positioned between the upper portion and the lower portion, the housing attached to a first end of a tether with a second end of the tether attached to the UAV, a slot in the housing that extends downwardly towards a center of the housing thereby forming a hook or lip on the lower portion of the housing beneath the slot, a plurality of holes in the upper portion of the housing, a plurality of holes in the side wall of the housing, and a plurality of holes positioned in the lower portion of the housing; (ii) moving the UAV forward at a rate of <NUM>-<NUM> m/s; (iii) retracting the payload coupling apparatus towards the UAV with the tether as the UAV moves forward at a rate of <NUM>-<NUM>/s; and (iv) wherein the payload coupling apparatus remains stable during retraction of the payload coupling apparatus.

The present embodiments further provide a system for retracting a payload coupling apparatus with means for providing stable, non-erratic payload coupling apparatus retraction at UAV cruise speed.

These as well as other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description with reference where appropriate to the accompanying drawings. Further, it should be understood that the description provided in this summary section and elsewhere in this document is intended to illustrate the claimed subject matter by way of example and not by way of limitation.

Exemplary methods and systems are described herein. It should be understood that the word "exemplary" is used herein to mean "serving as an example, instance, or illustration. " Any implementation or feature described herein as "exemplary" or "illustrative" is not necessarily to be construed as preferred or advantageous over other implementations or features. In the figures, similar symbols typically identify similar components, unless context dictates otherwise. The example implementations described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are contemplated herein.

As noted above, the payload coupling apparatus may provide for automated delivery of the payload. Upon arriving at a payload delivery site, the payload coupling apparatus and attached payload may be lowered by a winch within the UAV and the payload may land on the ground or payload receiving apparatus. Once the payload contacts the ground or payload receiving apparatus, the payload coupling apparatus may be further lowered by the winch and automatically disengage from the handle of the payload. Once the payload coupling apparatus is disengaged from the payload, the UAV may move into forward flight to another payload retrieval site or charging station, with the payload coupling apparatus suspended from the UAV at the end of the winch line. As the UAV moves forward, the payload coupling apparatus may be winched back towards the UAV. In this manner, the UAV does not have to wait until the payload coupling apparatus has been winched back to the UAV before the UAV moves towards the next destination.

Following payload delivery, the payload coupling apparatus is subject to oscillations, and may begin to swing from side to side. In order to dampen the oscillations, the UAV moves into a forward flight where airflow serves to reduce oscillations of the payload coupling apparatus. When using a solid, smooth-walled payload coupling apparatus, forward movement of the UAV at air speeds of around <NUM> meters per second (m/s) may be effective to dampen the oscillations of the payload coupling apparatus. However, if the air speed is too low, less than <NUM>/s, then the dampening effect on the oscillations of the payload might not be sufficient. In addition, at speeds above <NUM>/s, the payload coupling apparatus becomes unstable with the increased airflow and bounces around wildly and may strike the UAV, and there is the possibility of engagement with the rotors of the UAV. Therefore, when using a solid, smooth-walled payload coupling apparatus, a range of air speeds from <NUM>-<NUM>/s is suitable to dampen the oscillations of the payload coupling apparatus. Air speeds in the range of <NUM>-<NUM>/s, depending on the UAV, may be too slow for the UAV to be "on the wing" in full forward flight requiring that the hover motors of the UAV are still running, which increases energy consumption and reduces the range of the UAV.

The present embodiments are directed to a payload coupling apparatus that has the same hook and lip construction as a standard smooth-walled payload coupling apparatus, but advantageously includes a series of perforations, or holes, in the major surfaces of the payload coupling apparatus which allow the payload coupling apparatus to remain stable even at increased air speeds of <NUM>-<NUM>/s or more. The series of perforations or holes serve to stabilize the payload coupling apparatus during retraction so that it remains in a calm, non-erratic state during high speed UAV flight of <NUM>-<NUM>/s or more.

The perforations may include a series of holes that are symmetrically positioned on the major surfaces of the payload coupling apparatus. The holes also may not be symmetrically positioned, but may be positioned to provide aerodynamic symmetry in such a manner that the holes "act" symmetrically. The holes also may be positioned in a non-symmetrical fashion, although holes positioned to provide aerodynamic symmetry are preferred. In particular, the payload coupling apparatus may have a hemispherically-shaped upper portion with a centrally located tether attachment point, or hole through which the tether may extend for internal attachment, that may be used to secure the payload coupling apparatus to a tether that is attached to a UAV. A series of holes are symmetrically positioned on the hemispherically-shaped upper portion, which may have an equal spacing therebetween. If the holes are not positioned symmetrically or in a manner to provide aerodynamic symmetry, an undesirable oscillatory up and down motion may result during flight. A side wall of the payload coupling apparatus beneath the hemispherically-shaped upper portion may also be provided having holes, and cams on the side wall also may include holes therein.

Similarly, the hook or lip of the payload coupling apparatus may have holes positioned therein that extend from the slot through the upper surface of the hook or lip, as well as holes positioned in the lower surface of the hook or lip. In addition, an upper surface of the slot may include one or more holes that extend from the slot into an interior of the payload coupling apparatus.

The holes extend through outer surfaces of the payload coupling apparatus into a hollow interior of the payload coupling apparatus. As a result, air is allowed to flow through the payload coupling apparatus, i.e. through the holes on the hemispherically-shaped upper surface and through the holes in the upper and lower surfaces of the slot and hook or lip, during high speed flight which allows for the payload coupling apparatus to remain in a stable position during retraction as the UAV moves at full cruise speed of <NUM>-<NUM>/s or more.

In addition, a weighted disc may be positioned within the payload coupling apparatus to provide a "weight-forward" payload coupling apparatus which contributes to increased high speed stability. Due to less material used for the payload coupling apparatus because of the holes, the disc may add weight to the payload coupling apparatus so that a desired overall weight may be achieved.

Furthermore, the weighted disc may have a centrally located aperture, or a plurality of holes, that provides an aerodynamic influence on the payload coupling apparatus. The size of the centrally located aperture of plurality of holes in the weighted disc may be adjusted so that the payload coupling apparatus rides higher or lower in the air column during retraction as the UAV moves at full cruise speed. It is desirable for the payload coupling apparatus to ride as low as possible in the air column so that it is further away from the UAV during flight, thereby further reducing the chance of the payload coupling apparatus coming into contact with the UAV during flight.

Herein, the terms "unmanned aerial vehicle" and "UAV" refer to any autonomous or semi-autonomous vehicle that is capable of performing some functions without a physically present human pilot.

A UAV can take various forms. For example, a UAV may take the form of a fixed-wing aircraft, a glider aircraft, a tail-sitter aircraft, a jet aircraft, a ducted fan aircraft, a lighter-than-air dirigible such as a blimp or steerable balloon, a rotorcraft such as a helicopter or multicopter, and/or an ornithopter, among other possibilities. Further, the terms "drone," "unmanned aerial vehicle system" (UAVS), or "unmanned aerial system" (UAS) may also be used to refer to a UAV.

<FIG> is an isometric view of an example UAV <NUM>. UAV <NUM> includes wing <NUM>, booms <NUM>, and a fuselage <NUM>. Wings <NUM> may be stationary and may generate lift based on the wing shape and the UAV's forward airspeed. For instance, the two wings <NUM> may have an airfoil-shaped cross section to produce an aerodynamic force on UAV <NUM>. Wing <NUM> may carry horizontal propulsion units <NUM>, and booms <NUM> may carry vertical propulsion units <NUM>. In operation, power for the propulsion units may be provided from a battery compartment <NUM> of fuselage <NUM>. Fuselage <NUM> may also include an avionics compartment <NUM>, an additional battery compartment (not shown) and/or a delivery unit (not shown, e.g., a winch system) for handling the payload. Fuselage <NUM> may be modular, and two or more compartments (e.g., battery compartment <NUM>, avionics compartment <NUM>, other payload and delivery compartments) may detachable from each other and securable to each other (e.g., mechanically, magnetically, or otherwise) to contiguously form at least a portion of fuselage <NUM>.

Booms <NUM> may terminate in rudders <NUM> for improved yaw control of UAV <NUM>. Further, wings <NUM> may terminate in wing tips <NUM> for improved control of lift of the UAV.

In the illustrated configuration, UAV <NUM> includes a structural frame. The structural frame may be referred to as a "structural H-frame" or an "H-frame" (not shown) of the UAV. The H-frame may include, within wings <NUM>, a wing spar (not shown) and, within booms <NUM>, boom carriers (not shown). The wing spar and the boom carriers may be made of carbon fiber, hard plastic, aluminum, light metal alloys, or other materials. The wing spar and the boom carriers may be connected with clamps. The wing spar may include pre-drilled holes for horizontal propulsion units <NUM>, and the boom carriers may include pre-drilled holes for vertical propulsion units <NUM>.

Fuselage <NUM> may be removably attached to the H-frame (e.g., attached to the wing spar by clamps, configured with grooves, protrusions or other features to mate with corresponding H-frame features, etc.). In other examples, fuselage <NUM> similarly may be removably attached to wings <NUM>. The removable attachment of fuselage <NUM> may improve quality and or modularity of UAV <NUM>. For example, electrical/mechanical components and/or subsystems of fuselage <NUM> may be tested separately from, and before being attached to, the H-frame. Similarly, printed circuit boards (PCBs) <NUM> may be tested separately from, and before being attached to, the boom carriers, therefore eliminating defective parts/subassemblies prior to completing the UAV. For example, components of fuselage <NUM> (e.g., avionics, battery unit, delivery units, an additional battery compartment, etc.) may be electrically tested before fuselage <NUM> is mounted to the H-frame. Furthermore, the motors and the electronics of PCBs <NUM> may also be electrically tested before the final assembly. Generally, the identification of the defective parts and subassemblies early in the assembly process lowers the overall cost and lead time of the UAV. Furthermore, different types/models of fuselage <NUM> may be attached to the H-frame, therefore improving the modularity of the design. Such modularity allows these various parts of UAV <NUM> to be upgraded without a substantial overhaul to the manufacturing process.

A wing shell and boom shells may be attached to the H-frame by adhesive elements (e.g., adhesive tape, double-sided adhesive tape, glue, etc.). Therefore, multiple shells may be attached to the H-frame instead of having a monolithic body sprayed onto the H-frame. The presence of the multiple shells may reduce the stresses induced by the coefficient of thermal expansion of the structural frame of the UAV. As a result, the UAV may have better dimensional accuracy and/or improved reliability.

Moreover, the same H-frame may be used with the wing shell and/or boom shells having different size and/or design, therefore improving the modularity and versatility of the UAV designs. The wing shell and/or the boom shells may be made of relatively light polymers (e.g., closed cell foam) covered by the harder, but relatively thin, plastic skins.

The power and/or control signals from fuselage <NUM> may be routed to PCBs <NUM> through cables running through fuselage <NUM>, wings <NUM>, and booms <NUM>. In the illustrated example, UAV <NUM> has four PCBs, but other numbers of PCBs are also possible. For example, UAV <NUM> may include two PCBs, one per the boom. The PCBs carry electronic components <NUM> including, for example, power converters, controllers, memory, passive components, etc. In operation, propulsion units <NUM> and <NUM> of UAV <NUM> are electrically connected to the PCBs.

Many variations on the illustrated UAV are possible. For instance, fixed-wing UAVs may include more or fewer rotor units (vertical or horizontal), and/or may utilize a ducted fan or multiple ducted fans for propulsion. Further, UAVs with more wings (e.g., an "x-wing" configuration with four wings), are also possible. Although <FIG> illustrates two wings <NUM>, two booms <NUM>, two horizontal propulsion units <NUM>, and six vertical propulsion units <NUM> per boom <NUM>, it should be appreciated that other variants of UAV <NUM> may be implemented with more or less of these components. For example, UAV <NUM> may include four wings <NUM>, four booms <NUM>, and more or less propulsion units (horizontal or vertical).

Many variations on the illustrated fixed-wing UAV are possible. For instance, fixed-wing UAVs may include more or fewer propellers, and/or may utilize a ducted fan or multiple ducted fans for propulsion. Further, UAVs with more wings (e.g., an "x-wing" configuration with four wings), with fewer wings, or even with no wings, are also possible.

It should be understood that references herein to an "unmanned" aerial vehicle or UAV can apply equally to autonomous and semi-autonomous aerial vehicles. In an autonomous implementation, all functionality of the aerial vehicle is automated; e.g., pre-programmed or controlled via real-time computer functionality that responds to input from various sensors and/or pre-determined information. In a semi-autonomous implementation, some functions of an aerial vehicle may be controlled by a human operator, while other functions are carried out autonomously. Further, a UAV may be configured to allow a remote operator to take over functions that can otherwise be controlled autonomously by the UAV. Yet further, a given type of function may be controlled remotely at one level of abstraction and performed autonomously at another level of abstraction. For example, a remote operator could control high level navigation decisions for a UAV, such as by specifying that the UAV should travel from one location to another (e.g., from a warehouse in a suburban area to a delivery address in a nearby city), while the UAV's navigation system autonomously controls more fine-grained navigation decisions, such as the specific route to take between the two locations, specific flight controls to achieve the route and avoid obstacles while navigating the route, and so on.

More generally, it should be understood that the example UAVs described herein are not intended to be limiting and that any type of unmanned aerial vehicle may be utilized.

<FIG> is a simplified block diagram illustrating components of a UAV <NUM>. UAV <NUM> may take the form of, or be similar in form to, one of the UAVs <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> described in reference to Figures 1A-1E. However, UAV <NUM> may also take other forms.

UAV <NUM> may include various types of sensors, and may include a computing system configured to provide the functionality described herein. In the example illustrated in <FIG>, the sensors of UAV <NUM> include an inertial measurement unit (IMU) <NUM>, ultrasonic sensor(s) <NUM>, and a GPS <NUM>, among other possible sensors and sensing systems.

In the example illustrated in <FIG>, UAV <NUM> also includes one or more processors <NUM>. A processor <NUM> may be a general-purpose processor or a special purpose processor (e.g., digital signal processors, application specific integrated circuits, etc.). The one or more processors <NUM> can be configured to execute computer-readable program instructions <NUM> that are stored in the data storage <NUM> and are executable to provide the functionality of a UAV described herein.

The data storage <NUM> may include or take the form of one or more computer-readable storage media that can be read or accessed by at least one processor <NUM>. The one or more computer-readable storage media can include volatile and/or non-volatile storage components, such as optical, magnetic, organic or other memory or disc storage, which can be integrated in whole or in part with at least one of the one or more processors <NUM>. The data storage <NUM> can be implemented using a single physical device (e.g., one optical, magnetic, organic or other memory or disc storage unit) or, alternatively, the data storage <NUM> can be implemented using two or more physical devices.

As noted, the data storage <NUM> can include computer-readable program instructions <NUM> and perhaps additional data, such as diagnostic data of the UAV <NUM>. As such, the data storage <NUM> may include program instructions <NUM> to perform or facilitate some or all of the UAV functionality described herein. For instance, in the example illustrated in <FIG>, program instructions <NUM> include a navigation module <NUM> and a tether control module <NUM>.

IMU <NUM> may include both an accelerometer and a gyroscope, which may be used together to determine an orientation of the UAV <NUM>. In particular, the accelerometer can measure the orientation of the vehicle with respect to earth, while the gyroscope measures the rate of rotation around an axis. IMUs are commercially available in low-cost, low-power packages. For instance, an IMU <NUM> may take the form of or include a miniaturized MicroElectroMechanical System (MEMS) or a NanoElectroMechanical System (NEMS). Other types of IMUs may also be utilized.

An IMU <NUM> may include other sensors, in addition to accelerometers and gyroscopes, which may help to better determine position and/or help to increase autonomy of the UAV <NUM>. Two examples of such sensors are magnetometers and pressure sensors. For instance, a UAV may include a low-power, digital <NUM>-axis magnetometer, which can be used to realize an orientation independent electronic compass for accurate heading information. However, other types of magnetometers may be utilized as well. Further, note that a UAV could include some or all of the above-described inertia sensors as separate components from an IMU.

UAV <NUM> may also include a pressure sensor or barometer, which can be used to determine the altitude of the UAV <NUM>. Alternatively, other sensors, such as sonic altimeters or radar altimeters, can be used to provide an indication of altitude, which may help to improve the accuracy of and/or prevent drift of an IMU.

In a further aspect, UAV <NUM> may include one or more sensors that allow the UAV to sense objects in the environment. For instance, in the example illustrated in <FIG>, UAV <NUM> includes ultrasonic sensor(s) <NUM>. Ultrasonic sensor(s) <NUM> can determine the distance to an object by generating sound waves and determining the time interval between transmission of the wave and receiving the corresponding echo off an object. A typical application of an ultrasonic sensor for unmanned vehicles or IMUs is low-level altitude control and obstacle avoidance. An ultrasonic sensor can also be used for vehicles that need to hover at a certain height or need to be capable of detecting obstacles. Other systems can be used to determine, sense the presence of, and/or determine the distance to nearby objects, such as a light detection and ranging (LIDAR) system, laser detection and ranging (LADAR) system, and/or an infrared or forward-looking infrared (FLIR) system, among other possibilities.

In some examples, UAV <NUM> may also include one or more imaging system(s). For example, one or more still and/or video cameras may be utilized by UAV <NUM> to capture image data from the UAV's environment. As a specific example, charge-coupled device (CCD) cameras or complementary metal-oxide-semiconductor (CMOS) cameras can be used with unmanned vehicles. Such imaging sensor(s) have numerous possible applications, such as obstacle avoidance, localization techniques, ground tracking for more accurate navigation (e.g., by applying optical flow techniques to images), video feedback, and/or image recognition and processing, among other possibilities.

UAV <NUM> may also include a GPS receiver <NUM>. The GPS receiver <NUM> may be configured to provide data that is typical of well-known GPS systems, such as the GPS coordinates of the UAV <NUM>. Such GPS data may be utilized by the UAV <NUM> for various functions. As such, the UAV may use its GPS receiver <NUM> to help navigate to the caller's location, as indicated, at least in part, by the GPS coordinates provided by their mobile device.

The navigation module <NUM> may provide functionality that allows the UAV <NUM> to, e.g., move about its environment and reach a desired location. To do so, the navigation module <NUM> may control the altitude and/or direction of flight by controlling the mechanical features of the UAV that affect flight (e.g., its rudder(s), elevator(s), aileron(s), and/or the speed of its propeller(s)).

In order to navigate the UAV <NUM> to a target location, the navigation module <NUM> may implement various navigation techniques, such as map-based navigation and localization-based navigation, for instance. With map-based navigation, the UAV <NUM> may be provided with a map of its environment, which may then be used to navigate to a particular location on the map. With localization-based navigation, the UAV <NUM> may be capable of navigating in an unknown environment using localization. Localization-based navigation may involve the UAV <NUM> building its own map of its environment and calculating its position within the map and/or the position of objects in the environment. For example, as a UAV <NUM> moves throughout its environment, the UAV <NUM> may continuously use localization to update its map of the environment. This continuous mapping process may be referred to as simultaneous localization and mapping (SLAM). Other navigation techniques may also be utilized.

In some examples, the navigation module <NUM> may navigate using a technique that relies on waypoints. In particular, waypoints are sets of coordinates that identify points in physical space. For instance, an air-navigation waypoint may be defined by a certain latitude, longitude, and altitude. Accordingly, navigation module <NUM> may cause UAV <NUM> to move from waypoint to waypoint, in order to ultimately travel to a final destination (e.g., a final waypoint in a sequence of waypoints).

In a further aspect, the navigation module <NUM> and/or other components and systems of the UAV <NUM> may be configured for "localization" to more precisely navigate to the scene of a target location. More specifically, it may be desirable in certain situations for a UAV to be within a threshold distance of the target location where a payload <NUM> is being delivered by a UAV (e.g., within a few feet of the target destination). To this end, a UAV may use a two-tiered approach in which it uses a more-general location-determination technique to navigate to a general area that is associated with the target location, and then use a more-refined location-determination technique to identify and/or navigate to the target location within the general area.

For example, the UAV <NUM> may navigate to the general area of a target destination where a payload <NUM> is being delivered using waypoints and/or map-based navigation. The UAV may then switch to a mode in which it utilizes a localization process to locate and travel to a more specific location. For instance, if the UAV <NUM> is to deliver a payload to a user's home, the UAV <NUM> may need to be substantially close to the target location in order to avoid delivery of the payload to undesired areas (e.g., onto a roof, into a pool, onto a neighbor's property, etc.). However, a GPS signal may only get the UAV <NUM> so far (e.g., within a block of the user's home). A more precise location-determination technique may then be used to find the specific target location.

Various types of location-determination techniques may be used to accomplish localization of the target delivery location once the UAV <NUM> has navigated to the general area of the target delivery location. For instance, the UAV <NUM> may be equipped with one or more sensory systems, such as, for example, ultrasonic sensors <NUM>, infrared sensors (not shown), and/or other sensors, which may provide input that the navigation module <NUM> utilizes to navigate autonomously or semi-autonomously to the specific target location.

As another example, once the UAV <NUM> reaches the general area of the target delivery location (or of a moving subject such as a person or their mobile device), the UAV <NUM> may switch to a "fly-by-wire" mode where it is controlled, at least in part, by a remote operator, who can navigate the UAV <NUM> to the specific target location. To this end, sensory data from the UAV <NUM> may be sent to the remote operator to assist them in navigating the UAV <NUM> to the specific location.

As yet another example, the UAV <NUM> may include a module that is able to signal to a passer-by for assistance in either reaching the specific target delivery location; for example, the UAV <NUM> may display a visual message requesting such assistance in a graphic display, play an audio message or tone through speakers to indicate the need for such assistance, among other possibilities. Such a visual or audio message might indicate that assistance is needed in delivering the UAV <NUM> to a particular person or a particular location, and might provide information to assist the passer-by in delivering the UAV <NUM> to the person or location (e.g., a description or picture of the person or location, and/or the person or location's name), among other possibilities. Such a feature can be useful in a scenario in which the UAV is unable to use sensory functions or another location-determination technique to reach the specific target location. However, this feature is not limited to such scenarios.

In some examples, once the UAV <NUM> arrives at the general area of a target delivery location, the UAV <NUM> may utilize a beacon from a user's remote device (e.g., the user's mobile phone) to locate the person. Such a beacon may take various forms. As an example, consider the scenario where a remote device, such as the mobile phone of a person who requested a UAV delivery, is able to send out directional signals (e.g., via an RF signal, a light signal and/or an audio signal). In this scenario, the UAV <NUM> may be configured to navigate by "sourcing" such directional signals - in other words, by determining where the signal is strongest and navigating accordingly. As another example, a mobile device can emit a frequency, either in the human range or outside the human range, and the UAV <NUM> can listen for that frequency and navigate accordingly. As a related example, if the UAV <NUM> is listening for spoken commands, then the UAV <NUM> could utilize spoken statements, such as "I'm over here!" to source the specific location of the person requesting delivery of a payload.

In an alternative arrangement, a navigation module may be implemented at a remote computing device, which communicates wirelessly with the UAV <NUM>. The remote computing device may receive data indicating the operational state of the UAV <NUM>, sensor data from the UAV <NUM> that allows it to assess the environmental conditions being experienced by the UAV <NUM>, and/or location information for the UAV <NUM>. Provided with such information, the remote computing device may determine altitudinal and/or directional adjustments that should be made by the UAV <NUM> and/or may determine how the UAV <NUM> should adjust its mechanical features (e.g., its rudder(s), elevator(s), aileron(s), and/or the speed of its propeller(s)) in order to effectuate such movements. The remote computing system may then communicate such adjustments to the UAV <NUM> so it can move in the determined manner.

In a further aspect, the UAV <NUM> includes one or more communication systems <NUM>. The communications systems <NUM> may include one or more wireless interfaces and/or one or more wireline interfaces, which allow the UAV <NUM> to communicate via one or more networks. Such wireless interfaces may provide for communication under one or more wireless communication protocols, such as Bluetooth, WiFi (e.g., an IEEE <NUM> protocol), Long-Term Evolution (LTE), WiMAX (e.g., an IEEE <NUM> standard), a radio-frequency ID (RFID) protocol, near-field communication (NFC), and/or other wireless communication protocols. Such wireline interfaces may include an Ethernet interface, a Universal Serial Bus (USB) interface, or similar interface to communicate via a wire, a twisted pair of wires, a coaxial cable, an optical link, a fiber-optic link, or other physical connection to a wireline network.

In some examples, a UAV <NUM> may include communication systems <NUM> that allow for both short-range communication and long-range communication. For example, the UAV <NUM> may be configured for short-range communications using Bluetooth and for long-range communications under a CDMA protocol. In such an example, the UAV <NUM> may be configured to function as a "hot spot;" or in other words, as a gateway or proxy between a remote support device and one or more data networks, such as a cellular network and/or the Internet. Configured as such, the UAV <NUM> may facilitate data communications that the remote support device would otherwise be unable to perform by itself.

For example, the UAV <NUM> may provide a WiFi connection to a remote device, and serve as a proxy or gateway to a cellular service provider's data network, which the UAV might connect to under an LTE or a <NUM> protocol, for instance. The UAV <NUM> could also serve as a proxy or gateway to a high-altitude balloon network, a satellite network, or a combination of these networks, among others, which a remote device might not be able to otherwise access.

In a further aspect, the UAV <NUM> may include power system(s) <NUM>. The power system <NUM> may include one or more batteries for providing power to the UAV <NUM>. In one example, the one or more batteries may be rechargeable and each battery may be recharged via a wired connection between the battery and a power supply and/or via a wireless charging system, such as an inductive charging system that applies an external time-varying magnetic field to an internal battery.

The UAV <NUM> may employ various systems and configurations in order to transport and deliver a payload <NUM>. In some implementations, the payload <NUM> of a given UAV <NUM> may include or take the form of a "package" designed to transport various goods to a target delivery location. For example, the UAV <NUM> can include a compartment, in which an item or items may be transported. Such a package may one or more food items, purchased goods, medical items, or any other object(s) having a size and weight suitable to be transported between two locations by the UAV. In other examples, a payload <NUM> may simply be the one or more items that are being delivered (e.g., without any package housing the items).

The payload <NUM> may be attached to the UAV and located substantially outside of the UAV during some or all of a flight by the UAV. For example, the package may be tethered or otherwise releasably attached below the UAV during flight to a target location. In implementations in which a package carries goods below the UAV, the package may include various features that protect its contents from the environment, reduce aerodynamic drag on the system, and prevent the contents of the package from shifting during UAV flight.

For instance, when the payload <NUM> takes the form of a package for transporting items, the package may include an outer shell constructed of water-resistant cardboard, plastic, or any other lightweight and water-resistant material. Further, in order to reduce drag, the package may feature smooth surfaces with a pointed front that reduces the frontal cross-sectional area. Further, the sides of the package may taper from a wide bottom to a narrow top, which allows the package to serve as a narrow pylon that reduces interference effects on the wing(s) of the UAV. This may move some of the frontal area and volume of the package away from the wing(s) of the UAV, thereby preventing the reduction of lift on the wing(s) caused by the package. Yet further, the outer shell of the package may be constructed from a single sheet of material in order to reduce air gaps or extra material, both of which may increase drag on the system. Additionally or alternatively, the package may include a stabilizer to dampen package flutter. This reduction in flutter may allow the package to have a less rigid connection to the UAV and may cause the contents of the package to shift less during flight.

In order to deliver the payload, the UAV may include a winch system <NUM> controlled by the tether control module <NUM> in order to lower the payload <NUM> to the ground while the UAV hovers above. As shown in <FIG>, the winch system <NUM> may include a tether <NUM>, and the tether <NUM> may be coupled to the payload <NUM> by a payload coupling apparatus <NUM>. The tether <NUM> may be wound on a spool that is coupled to a motor <NUM> of the UAV. The motor <NUM> may take the form of a DC motor (e.g., a servo motor) that can be actively controlled by a speed controller. The tether control module <NUM> can control the speed controller to cause the motor <NUM> to rotate the spool, thereby unwinding or retracting the tether <NUM> and lowering or raising the payload coupling apparatus <NUM>. In practice, the speed controller may output a desired operating rate (e.g., a desired RPM) for the spool, which may correspond to the speed at which the tether <NUM> and payload <NUM> should be lowered towards the ground. The motor <NUM> may then rotate the spool so that it maintains the desired operating rate.

In order to control the motor <NUM> via the speed controller, the tether control module <NUM> may receive data from a speed sensor (e.g., an encoder) configured to convert a mechanical position to a representative analog or digital signal. In particular, the speed sensor may include a rotary encoder that may provide information related to rotary position (and/or rotary movement) of a shaft of the motor or the spool coupled to the motor, among other possibilities. Moreover, the speed sensor may take the form of an absolute encoder and/or an incremental encoder, among others. So in an example implementation, as the motor <NUM> causes rotation of the spool, a rotary encoder may be used to measure this rotation. In doing so, the rotary encoder may be used to convert a rotary position to an analog or digital electronic signal used by the tether control module <NUM> to determine the amount of rotation of the spool from a fixed reference angle and/or to an analog or digital electronic signal that is representative of a new rotary position, among other options.

Based on the data from the speed sensor, the tether control module <NUM> may determine a rotational speed of the motor <NUM> and/or the spool and responsively control the motor <NUM> (e.g., by increasing or decreasing an electrical current supplied to the motor <NUM>) to cause the rotational speed of the motor <NUM> to match a desired speed. When adjusting the motor current, the magnitude of the current adjustment may be based on a proportional-integral-derivative (PID) calculation using the determined and desired speeds of the motor <NUM>. For instance, the magnitude of the current adjustment may be based on a present difference, a past difference (based on accumulated error over time), and a future difference (based on current rates of change) between the determined and desired speeds of the spool.

The tether control module <NUM> may vary the rate at which the tether <NUM> and payload <NUM> are lowered to the ground. For example, the speed controller may change the desired operating rate according to a variable deployment-rate profile and/or in response to other factors in order to change the rate at which the payload <NUM> descends toward the ground. To do so, the tether control module <NUM> may adjust an amount of braking or an amount of friction that is applied to the tether <NUM>. For example, to vary the tether deployment rate, the UAV <NUM> may include friction pads that can apply a variable amount of pressure to the tether <NUM>. As another example, the UAV <NUM> can include a motorized braking system that varies the rate at which the spool lets out the tether <NUM>. Such a braking system may take the form of an electromechanical system in which the motor <NUM> operates to slow the rate at which the spool lets out the tether <NUM>. Further, the motor <NUM> may vary the amount by which it adjusts the speed (e.g., the RPM) of the spool, and thus may vary the deployment rate of the tether <NUM>.

The tether control module <NUM> may be configured to limit the motor current supplied to the motor <NUM> to a maximum value. With such a limit placed on the motor current, there may be situations where the motor <NUM> cannot operate at the desired operate specified by the speed controller. For instance, as discussed in more detail below, there may be situations where the speed controller specifies a desired operating rate at which the motor <NUM> should retract the tether <NUM> toward the UAV <NUM>, but the motor current may be limited such that a large enough downward force on the tether <NUM> would counteract the retracting force of the motor <NUM> and cause the tether <NUM> to unwind instead. And as further discussed below, a limit on the motor current may be imposed and/or altered depending on an operational state of the UAV <NUM>.

The tether control module <NUM> may be configured to determine a status of the tether <NUM> and/or the payload <NUM> based on the amount of current supplied to the motor <NUM>. For instance, if a downward force is applied to the tether <NUM> (e.g., if the payload <NUM> is attached to the tether <NUM> or if the tether <NUM> gets snagged on an object when retracting toward the UAV <NUM>), the tether control module <NUM> may need to increase the motor current in order to cause the determined rotational speed of the motor <NUM> and/or spool to match the desired speed. Similarly, when the downward force is removed from the tether <NUM> (e.g., upon delivery of the payload <NUM> or removal of a tether snag), the tether control module <NUM> may need to decrease the motor current in order to cause the determined rotational speed of the motor <NUM> and/or spool to match the desired speed. As such, the tether control module <NUM> may be configured to monitor the current supplied to the motor <NUM>. For instance, the tether control module <NUM> could determine the motor current based on sensor data received from a current sensor of the motor or a current sensor of the power system <NUM>. In any case, based on the current supplied to the motor <NUM>, determine if the payload <NUM> is attached to the tether <NUM>, if someone or something is pulling on the tether <NUM>, and/or if the payload coupling apparatus <NUM> is pressing against the UAV <NUM> after retracting the tether <NUM>. Other examples are possible as well.

During delivery of the payload <NUM>, the payload coupling apparatus <NUM> can be configured to secure the payload <NUM> while being lowered from the UAV by the tether <NUM>, and can be further configured to release the payload <NUM> upon reaching ground level. The payload coupling apparatus <NUM> can then be retracted to the UAV by reeling in the tether <NUM> using the motor <NUM>.

In some implementations, the payload <NUM> may be passively released once it is lowered to the ground. For example, a passive release mechanism may include one or more swing arms adapted to retract into and extend from a housing. An extended swing arm may form a hook on which the payload <NUM> may be attached. Upon lowering the release mechanism and the payload <NUM> to the ground via a tether, a gravitational force as well as a downward inertial force on the release mechanism may cause the payload <NUM> to detach from the hook allowing the release mechanism to be raised upwards toward the UAV. The release mechanism may further include a spring mechanism that biases the swing arm to retract into the housing when there are no other external forces on the swing arm. For instance, a spring may exert a force on the swing arm that pushes or pulls the swing arm toward the housing such that the swing arm retracts into the housing once the weight of the payload <NUM> no longer forces the swing arm to extend from the housing. Retracting the swing arm into the housing may reduce the likelihood of the release mechanism snagging the payload <NUM> or other nearby objects when raising the release mechanism toward the UAV upon delivery of the payload <NUM>.

Active payload release mechanisms are also possible. For example, sensors such as a barometric pressure based altimeter and/or accelerometers may help to detect the position of the release mechanism (and the payload) relative to the ground. Data from the sensors can be communicated back to the UAV and/or a control system over a wireless link and used to help in determining when the release mechanism has reached ground level (e.g., by detecting a measurement with the accelerometer that is characteristic of ground impact). In other examples, the UAV may determine that the payload has reached the ground based on a weight sensor detecting a threshold low downward force on the tether and/or based on a threshold low measurement of power drawn by the winch when lowering the payload.

Other systems and techniques for delivering a payload, in addition or in the alternative to a tethered delivery system are also possible. For example, a UAV <NUM> could include an air-bag drop system or a parachute drop system. Alternatively, a UAV <NUM> carrying a payload could simply land on the ground at a delivery location.

UAV systems may be implemented in order to provide various UAV-related services. In particular, UAVs may be provided at a number of different launch sites that may be in communication with regional and/or central control systems. Such a distributed UAV system may allow UAVs to be quickly deployed to provide services across a large geographic area (e.g., that is much larger than the flight range of any single UAV). For example, UAVs capable of carrying payloads may be distributed at a number of launch sites across a large geographic area (possibly even throughout an entire country, or even worldwide), in order to provide on-demand transport of various items to locations throughout the geographic area. <FIG> is a simplified block diagram illustrating a distributed UAV system <NUM>.

In the illustrative UAV system <NUM>, an access system <NUM> may allow for interaction with, control of, and/or utilization of a network of UAVs <NUM>. An access system <NUM> may be a computing system that allows for human-controlled dispatch of UAVs <NUM>. As such, the control system may include or otherwise provide a user interface through which a user can access and/or control the UAVs <NUM>.

Dispatch of the UAVs <NUM> may additionally or alternatively be accomplished via one or more automated processes. For instance, the access system <NUM> may dispatch one of the UAVs <NUM> to transport a payload to a target location, and the UAV may autonomously navigate to the target location by utilizing various on-board sensors, such as a GPS receiver and/or other various navigational sensors.

Further, the access system <NUM> may provide for remote operation of a UAV. For instance, the access system <NUM> may allow an operator to control the flight of a UAV via its user interface. As a specific example, an operator may use the access system <NUM> to dispatch a UAV <NUM> to a target location. The UAV <NUM> may then autonomously navigate to the general area of the target location. At this point, the operator may use the access system <NUM> to take control of the UAV <NUM> and navigate the UAV to the target location (e.g., to a particular person to whom a payload is being transported). Other examples of remote operation of a UAV are also possible.

The UAVs <NUM> may take various forms. For example, each of the UAVs <NUM> may be a UAV such as those illustrated in Figures 1A-1E. However, UAV system <NUM> may also utilize other types of UAVs. In some implementations, all of the UAVs <NUM> may be of the same or a similar configuration. However, in other implementations, the UAVs <NUM> may include a number of different types of UAVs. For instance, the UAVs <NUM> may include a number of types of UAVs, with each type of UAV being configured for a different type or types of payload delivery capabilities.

The UAV system <NUM> may further include a remote device <NUM>, which may take various forms. Generally, the remote device <NUM> may be any device through which a direct or indirect request to dispatch a UAV can be made. (Note that an indirect request may involve any communication that may be responded to by dispatching a UAV, such as requesting a package delivery). For example, the remote device <NUM> may be a mobile phone, tablet computer, laptop computer, personal computer, or any network-connected computing device. Further, in some instances, the remote device <NUM> may not be a computing device. As an example, a standard telephone, which allows for communication via plain old telephone service (POTS), may serve as the remote device <NUM>. Other types of remote devices are also possible.

Further, the remote device <NUM> may be configured to communicate with access system <NUM> via one or more types of communication network(s) <NUM>. For example, the remote device <NUM> may communicate with the access system <NUM> (or a human operator of the access system <NUM>) by communicating over a POTS network, a cellular network, and/or a data network such as the Internet. Other types of networks may also be utilized.

The remote device <NUM> may be configured to allow a user to request delivery of one or more items to a desired location. For example, a user could request UAV delivery of a package to their home via their mobile phone, tablet, or laptop. As another example, a user could request dynamic delivery to wherever they are located at the time of delivery. To provide such dynamic delivery, the UAV system <NUM> may receive location information (e.g., GPS coordinates, etc.) from the user's mobile phone, or any other device on the user's person, such that a UAV can navigate to the user's location (as indicated by their mobile phone).

In an illustrative arrangement, the central dispatch system <NUM> may be a server or group of servers, which is configured to receive dispatch messages requests and/or dispatch instructions from the access system <NUM>. Such dispatch messages may request or instruct the central dispatch system <NUM> to coordinate the deployment of UAVs to various target locations. The central dispatch system <NUM> may be further configured to route such requests or instructions to one or more local dispatch systems <NUM>. To provide such functionality, the central dispatch system <NUM> may communicate with the access system <NUM> via a data network, such as the Internet or a private network that is established for communications between access systems and automated dispatch systems.

In the illustrated configuration, the central dispatch system <NUM> may be configured to coordinate the dispatch of UAVs <NUM> from a number of different local dispatch systems <NUM>. As such, the central dispatch system <NUM> may keep track of which UAVs <NUM> are located at which local dispatch systems <NUM>, which UAVs <NUM> are currently available for deployment, and/or which services or operations each of the UAVs <NUM> is configured for (in the event that a UAV fleet includes multiple types of UAVs configured for different services and/or operations). Additionally or alternatively, each local dispatch system <NUM> may be configured to track which of its associated UAVs <NUM> are currently available for deployment and/or are currently in the midst of item transport.

In some cases, when the central dispatch system <NUM> receives a request for UAV-related service (e.g., transport of an item) from the access system <NUM>, the central dispatch system <NUM> may select a specific UAV <NUM> to dispatch. The central dispatch system <NUM> may accordingly instruct the local dispatch system <NUM> that is associated with the selected UAV to dispatch the selected UAV. The local dispatch system <NUM> may then operate its associated deployment system <NUM> to launch the selected UAV. In other cases, the central dispatch system <NUM> may forward a request for a UAV-related service to a local dispatch system <NUM> that is near the location where the support is requested and leave the selection of a particular UAV <NUM> to the local dispatch system <NUM>.

In an example configuration, the local dispatch system <NUM> may be implemented as a computing system at the same location as the deployment system(s) <NUM> that it controls. For example, the local dispatch system <NUM> may be implemented by a computing system installed at a building, such as a warehouse, where the deployment system(s) <NUM> and UAV(s) <NUM> that are associated with the particular local dispatch system <NUM> are also located. Alternatively, the local dispatch system <NUM> may be implemented at a location that is remote to its associated deployment system(s) <NUM> and UAV(s) <NUM>.

Numerous variations on and alternatives to the illustrated configuration of the UAV system <NUM> are possible. For example, a user of the remote device <NUM> could request delivery of a package directly from the central dispatch system <NUM>. To do so, an application may be implemented on the remote device <NUM> that allows the user to provide information regarding a requested delivery, and generate and send a data message to request that the UAV system <NUM> provide the delivery. In such an example, the central dispatch system <NUM> may include automated functionality to handle requests that are generated by such an application, evaluate such requests, and, if appropriate, coordinate with an appropriate local dispatch system <NUM> to deploy a UAV.

Further, some or all of the functionality that is attributed herein to the central dispatch system <NUM>, the local dispatch system(s) <NUM>, the access system <NUM>, and/or the deployment system(s) <NUM> may be combined in a single system, implemented in a more complex system, and/or redistributed among the central dispatch system <NUM>, the local dispatch system(s) <NUM>, the access system <NUM>, and/or the deployment system(s) <NUM> in various ways.

Yet further, while each local dispatch system <NUM> is shown as having two associated deployment systems <NUM>, a given local dispatch system <NUM> may alternatively have more or fewer associated deployment systems <NUM>. Similarly, while the central dispatch system <NUM> is shown as being in communication with two local dispatch systems <NUM>, the central dispatch system <NUM> may alternatively be in communication with more or fewer local dispatch systems <NUM>.

In a further aspect, the deployment systems <NUM> may take various forms. In general, the deployment systems <NUM> may take the form of or include systems for physically launching one or more of the UAVs <NUM>. Such launch systems may include features that provide for an automated UAV launch and/or features that allow for a human-assisted UAV launch. Further, the deployment systems <NUM> may each be configured to launch one particular UAV <NUM>, or to launch multiple UAVs <NUM>.

The deployment systems <NUM> may further be configured to provide additional functions, including for example, diagnostic-related functions such as verifying system functionality of the UAV, verifying functionality of devices that are housed within a UAV (e.g., a payload delivery apparatus), and/or maintaining devices or other items that are housed in the UAV (e.g., by monitoring a status of a payload such as its temperature, weight, etc.).

The deployment systems <NUM> and their corresponding UAVs <NUM> (and possibly associated local dispatch systems <NUM>) may be strategically distributed throughout an area such as a city. For example, the deployment systems <NUM> may be strategically distributed such that each deployment system <NUM> is proximate to one or more payload pickup locations (e.g., near a restaurant, store, or warehouse). However, the deployment systems <NUM> (and possibly the local dispatch systems <NUM>) may be distributed in other ways, depending upon the particular implementation. As an additional example, kiosks that allow users to transport packages via UAVs may be installed in various locations. Such kiosks may include UAV launch systems, and may allow a user to provide their package for loading onto a UAV and pay for UAV shipping services, among other possibilities.

In a further aspect, the UAV system <NUM> may include or have access to a user-account database <NUM>. The user-account database <NUM> may include data for a number of user accounts, and which are each associated with one or more person. For a given user account, the user-account database <NUM> may include data related to or useful in providing UAV-related services. Typically, the user data associated with each user account is optionally provided by an associated user and/or is collected with the associated user's permission.

Further, a person may be required to register for a user account with the UAV system <NUM>, if they wish to be provided with UAV-related services by the UAVs <NUM> from UAV system <NUM>. As such, the user-account database <NUM> may include authorization information for a given user account (e.g., a user name and password), and/or other information that may be used to authorize access to a user account.

A person may associate one or more of their devices with their user account, such that they can access the services of UAV system <NUM>. For example, when a person uses an associated mobile phone, e.g., to place a call to an operator of the access system <NUM> or send a message requesting a UAV-related service to a dispatch system, the phone may be identified via a unique device identification number, and the call or message may then be attributed to the associated user account.

<FIG> show various perspective views of payload coupling apparatus <NUM>, according to an example embodiment. Payload coupling apparatus <NUM> includes an upper portion <NUM> having a left side 805a and a right side 805b. Upper portion <NUM> is shown as having a hemispherical shape, although other shapes and configurations, such as a cone-shape, are possible as well. Payload coupling apparatus <NUM> also includes a slot <NUM> to position a handle of a payload handle in. Lower lip, or hook, <NUM> is positioned beneath slot <NUM>, with lip or hook <NUM> having a left side 806a and a right side 806b. Slot <NUM> and lip or hook <NUM> are shown in a particular configuration, although payload coupling apparatus <NUM> may be provided with a slot of any suitable geometry or configuration, and a hook or lip of any suitable geometry or configuration suitable for the positioning of a handle of a payload within the slot above the hook or lip.

Payload coupling apparatus <NUM> further includes a side wall <NUM> having a left side 810a and right side 810b. Also included is an outer protrusion <NUM> having helical cam surfaces 804a and 804b that are adapted to mate with corresponding cam mating surfaces within a payload coupling apparatus receptacle <NUM> positioned with a fuselage of a UAV (as shown in <FIG>), to properly align payload coupling apparatus <NUM> within the payload coupling apparatus receptacle <NUM>.

Upper portion <NUM> includes a plurality of holes (described in more detail below) that extend from an exterior thereof into an interior of the payload coupling apparatus <NUM>. Holes on the left side 805a are shown to be symmetrical in size and position with holes on the right side 805b of upper portion <NUM>. Similarly, side wall <NUM> includes a plurality of holes with holes on the left side 810a symmetrical in size and position with holes on the right side 810b of side wall <NUM>.

Lower lip or hook <NUM> includes hole <NUM> on left side 806a symmetrical in size and position with hole <NUM> on right side 806b, and hole <NUM> on left side 806a symmetrical in size and position with hole <NUM> on right side 806b. Although not visible in <FIG>, hook or lip <NUM> further includes one or more holes an upper surface thereof. In addition, upper surface <NUM> of slot <NUM> includes a hole <NUM> that extends in symmetrical fashion from the left side to the right side of upper surface <NUM>. Upper surface <NUM> further includes hole <NUM> that extends in symmetrical fashion from the left side to the right side of upper surface <NUM>. In addition, hole <NUM> is positioned above cam surface 804b that is symmetrical in size and position with hole <NUM> positioned above cam surface 804a.

As shown in <FIG>, right side 810b of side wall <NUM> includes a an outer protrusion <NUM> having a cam surface <NUM> that is adapted to mate with corresponding cam mating surfaces within a payload coupling apparatus receptacle <NUM> positioned with a fuselage of a UAV (as shown in <FIG>), to properly align payload coupling apparatus <NUM> within the payload coupling apparatus receptacle <NUM>.

As shown in <FIG> and <FIG>, upper portion <NUM> includes an opening <NUM> through which an end of a tether may extend through for connection within upper portion <NUM>, or any other location within payload coupling apparatus <NUM>. Alternately, an end of a tether could be simply attached to the point where opening <NUM> is positioned. Also shown in <FIG> are a pair of symmetrical holes <NUM> and <NUM> positioned on side wall <NUM> above cam surface <NUM> of outer protrusion <NUM>. Also shown, are symmetrical holes <NUM> and <NUM> positioned next to holes <NUM> and <NUM>.

As shown in <FIG>, the rear side of lower portion of payload coupling apparatus <NUM> includes a hole <NUM> on the left side 806a symmetrical in size and position with hole <NUM> on right side 806b. Similarly, the rear side of lower portion of payload coupling apparatus <NUM> includes a hole <NUM> on left side 806a symmetrical in size and position with hole <NUM> on right side 806b, and also includes hole <NUM> on left side 806a symmetrical in size and position with hole <NUM> on right side 806b.

As shown in <FIG>, a hole <NUM> is shown positioned beneath outer protrusion <NUM> that is symmetrical in size and position with hole <NUM> positioned beneath outer protrusion <NUM> (shown in <FIG>).

<FIG> show side views, front and rear views, and top and bottom views of payload coupling apparatus <NUM> shown in <FIG>. <FIG> is a left side view of payload coupling apparatus <NUM>. Payload coupling apparatus <NUM> includes an upper portion <NUM> having left side 805a with a plurality of holes therein (described in more detail below). Payload coupling apparatus <NUM> also includes a slot <NUM> to position a handle of a payload handle in. Lower lip, or hook, <NUM> is positioned beneath slot <NUM>, with lip or hook <NUM> with left side 806a shown. Slot <NUM> is downwardly angled such that a handle <NUM> of a payload <NUM> may be positioned within the <NUM> slot with hook or lip <NUM> of the payload coupling apparatus <NUM> extending through an aperture <NUM> of handle <NUM> during payload pickup and delivery, as illustrated in <FIG>, <FIG>, and <FIG>.

Payload coupling apparatus <NUM> further includes a side wall <NUM> with left side 810a shown. Also included is an outer protrusion <NUM> having helical cam surfaces 804a and 804b that are adapted to mate with corresponding cam mating surfaces within a payload coupling apparatus receptacle <NUM> positioned with a fuselage of a UAV (as shown in <FIG>), to properly align payload coupling apparatus <NUM> within the payload coupling apparatus receptacle <NUM>. Hole <NUM> is positioned above cam surface 804b that is symmetrical in size and position with hole <NUM> positioned above cam surface 804a.

Outer protrusion <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> positioned in outer protrusion <NUM> (shown in <FIG>). Outer protrusion <NUM> also includes hole <NUM> that is symmetrical in size and position with hole <NUM> positioned in outer protrusion <NUM>, and further includes hole <NUM> that is symmetrical in size and position with hole <NUM> positioned in outer protrusion <NUM> (shown in <FIG>). Furthermore, outer protrusion <NUM> also includes hole <NUM> that is symmetrical in position with hole <NUM> positioned on outer protrusion <NUM> (shown in <FIG>). Moreover, hole <NUM> is positioned beneath outer protrusion <NUM> that is symmetrical in size and position with hole <NUM> positioned beneath outer protrusion <NUM> (shown in <FIG>).

<FIG> is a right side view of payload coupling apparatus <NUM>. In <FIG>, a pair of symmetrical holes <NUM> and <NUM> are positioned on right side 810b of side wall <NUM> above cam surface <NUM> of outer protrusion <NUM>. Also shown are symmetrical holes <NUM> and <NUM> positioned next to holes <NUM> and <NUM>.

<FIG> is a rear view of payload coupling apparatus <NUM>. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b.

In addition, left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM>. On right side 810b.

The rear side of hook or lip <NUM> includes left side 806a with hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 806b. Left side 806a includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 806b. In addition, left side 806a includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 806a. Also shown, is hole <NUM> positioned beneath outer protrusion <NUM> that is symmetrical in size and position with hole <NUM> positioned beneath outer protrusion <NUM>.

<FIG> is a front view of payload coupling apparatus <NUM>. Hole <NUM> is positioned above outer protrusion <NUM> on left side 810a of side wall <NUM> which is symmetrical in size and position with hole <NUM> positioned above outer protrusion <NUM> on the right side 810b of side wall <NUM>. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b. Left side 810a of side wall <NUM> includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 810b.

Lower lip or hook <NUM> includes hole <NUM> on left side 806a symmetrical in size and position with hole <NUM> on right side 806b, and hole <NUM> on left side 806a symmetrical in size and position with hole <NUM> on right side 806b. Hook or lip <NUM> further includes hole <NUM> on an upper surface thereof (shown in <FIG>). In addition, upper surface <NUM> of slot <NUM> includes a hole <NUM> that extends in symmetrical fashion from the left side to the right side of upper surface <NUM>. Upper surface <NUM> further includes hole <NUM> that extends in symmetrical fashion from the left side to the right side of upper surface <NUM>.

<FIG> is a top view of payload coupling apparatus <NUM>. Hole <NUM> is centrally located on the top of upper portion <NUM>, and an end of a tether may extend therethrough and be attached on the inside of payload coupling apparatus <NUM>. Left side 805a of upper portion <NUM> includes a pair of spaced holes <NUM> and <NUM> that are symmetrical in size and position with pair of holes <NUM> and <NUM> on right side 805b. Left side 805a of upper portion includes a pair of holes <NUM> and <NUM> that are symmetrical in size and position with pair of holes <NUM> and <NUM> on right side 805b. Left side 805a of upper portion <NUM> includes holes <NUM> and <NUM> that are symmetrical in size and position with pair of holes <NUM> and <NUM> on right side 805b. Left side 805a of upper portion <NUM> includes a pair of holes <NUM> and <NUM> that are symmetrical in size and position with pair of holes <NUM> and <NUM> on right side 805b.

Left side 805a of upper portion <NUM> further includes a pair of spaced holes <NUM> and <NUM> that are symmetrical in size and position with pair of holes <NUM> and <NUM> on right side 805b. Left side 805a of upper portion includes a pair of holes <NUM> and <NUM> that are symmetrical in size and position with pair of holes <NUM> and <NUM> on right side 805b.

<FIG> is a bottom view of payload coupling apparatus <NUM>. Hole <NUM> is positioned on the left side 806a of bottom of lower hook or lip <NUM> that is symmetrical in size and position with hole <NUM> positioned on right side 806b. Left side 806a further includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 806b. Left side 806a includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 8060b.

Hole <NUM> is shown extending symmetrically from the left side to the right side of upper surface <NUM> of slot <NUM>. Left side 806a includes hole <NUM> that is symmetrical in size and position with hole <NUM> on right side 806b. In addition, a pair of holes <NUM> and <NUM> are positioned on right side 806a that are symmetrical in size and position with pair of holes <NUM> and <NUM> positioned on right side 806b.

It will be appreciated that the size, position, geometry, and configuration of the various holes described above may be changed to different sizes, positions, geometries, and configurations as long as the resulting payload coupling apparatus falls within the scope of claim <NUM>. Preferably, although not required, holes positioned on the left side of the payload coupling apparatus <NUM> are symmetrical in size and position with the holes positioned on the right side of payload coupling apparatus <NUM>.

As shown in <FIG> and <FIG>, payload coupling apparatus is formed with a left side 800a and right side 800b. Left and right sides 800a and 800b may be molded, or 3D printed, and made of any suitable material. Left and right sides 800a and 800b may be joined together with an adhesive, or heat sealed together. A fastener such as a bolt may extend through hole <NUM> in right side 800b and thread into mounting extension 873a within left side 800b, which further serves to hold left side 800a together with right side 800b.

As shown in <FIG>, because of the many holes in the surface of payload coupling apparatus <NUM>, it is lighter than payload coupling apparatus <NUM>' that has smooth walls and is without holes, but has the same size and configuration as payload coupling apparatus <NUM>.

As shown in <FIG> and <FIG>, a weighted disc <NUM> may be positioned within payload coupling apparatus <NUM>. The weighted disc <NUM> may be slightly heavier than a weighted disc of a standard smooth-walled capsule to account for less material being used as a result of having the holes in payload coupling apparatus <NUM>. In addition, weighted disc <NUM> may include a centrally located aperture <NUM>. As the payload coupling apparatus <NUM> moves through the air during UAV flight and/or retraction, air may flow through upper portion <NUM>, through aperture <NUM> and through the lower end of payload coupling apparatus <NUM>. Air flow through the holes in payload coupling apparatus <NUM> provide stability to the payload coupling apparatus <NUM> during UAV flight and/or retraction. It will be appreciated that aperture <NUM> could be replaced with a plurality of holes on weighted disc <NUM> having various sizes and geometries, which may or may not be symmetrical with respect to each other.

<FIG> is a side view of an example of a payload handle <NUM> that is attached to payload <NUM> (shown in <FIG>) and which may be utilized with a payload coupling apparatus according to claim <NUM>. The handle <NUM> includes aperture <NUM> through which the hook or lip <NUM> of a payload coupling apparatus <NUM> extends through to suspend the payload during delivery, or during retrieval. The handle <NUM> includes a lower portion <NUM> that is secured to the top portion of a payload. Also included are holes <NUM> and <NUM> through which are adapted to receive locking pins (not shown) positioned within the fuselage of a UAV, where the locking pins may extend to further secure the handle and payload in a secure position during high speed forward flight to a delivery location. The handle <NUM> may be comprised of a thin, flexible plastic material that is flexible and provides sufficient strength to suspend the payload beneath a UAV during forward flight to a delivery site, and during delivery and/or retrieval of a payload. In practice, the handle may be bent or flexed to secure the handle <NUM> within the slot <NUM> of the payload retriever <NUM>. The handle <NUM> also has sufficient strength to withstand the torque during rotation of the payload retriever into the desired orientation within the payload receptacle, and rotation of the top portion of the payload into position within the recessed restraint slot <NUM> (shown in <FIG>).

<FIG> is a perspective view of payload <NUM> and payload coupling apparatus <NUM> shown suspended by tether <NUM> from a UAV, above payload landing site <NUM>, according to an example embodiment. As payload <NUM> is lowered to the payload landing site <NUM>, the payload is suspended from payload coupling apparatus <NUM>, with hook or lip <NUM> extending through aperture <NUM> of handle <NUM> of payload <NUM>.

<FIG> is a perspective view of payload <NUM> and payload coupling apparatus <NUM> being lowered by a UAV onto payload landing site <NUM>. <FIG> is a perspective view of payload <NUM> positioned on payload landing site <NUM> after payload coupling apparatus <NUM> has been lowered and moved out of engagement with handle <NUM> of payload <NUM>.

<FIG> is a perspective view of payload coupling apparatus <NUM> being retracted to UAV <NUM> after delivery of payload <NUM>. <FIG> is a perspective view of payload coupling apparatus <NUM> being retracted towards payload coupling apparatus receptacle <NUM>.

<FIG> are a perspective side by side view of payload coupling apparatus <NUM> having a plurality of holes and payload coupling apparatus <NUM>' having no holes and smooth walls. Payload coupling apparatus <NUM>' includes a hemispherically-shaped upper portion <NUM>', side wall <NUM>', outer protrusion <NUM>' and hook or lip <NUM>'.

After delivering payload <NUM>, as shown in <FIG>, the payload coupling apparatus <NUM> is disengaged from the handle <NUM> of payload <NUM>, and the UAV <NUM> may move into forward flight to another payload retrieval site or charging station, with the payload coupling apparatus <NUM> suspended from the UAV at the end of the winch line <NUM>. As the UAV <NUM> moves forward, the payload coupling apparatus <NUM> may be winched back towards the UAV <NUM> at the same time. In this manner, the UAV <NUM> does not have to wait until the payload coupling apparatus <NUM> has been winched all the way back to the UAV <NUM> before the UAV <NUM> moves towards the next destination.

As noted above, the payload coupling apparatus <NUM> is subject to oscillations, and may begin to swing from side to side as the UAV <NUM> moves into forward flight. In order to dampen the oscillations, the UAV <NUM> moves into a forward flight where airflow serves to reduce oscillations of the payload coupling apparatus <NUM>. When using a solid, smooth-walled payload coupling apparatus <NUM>' shown in <FIG>, forward movement of the UAV <NUM> at air speeds of around <NUM> meters per second (m/s) may be effective to dampen the oscillations of the payload coupling apparatus <NUM>'. However, if the air speed is too low, less than <NUM>/s, then dampening effect on the oscillations of the payload is reduced and might not be sufficient. In addition, at speeds above <NUM>/s, the payload coupling apparatus <NUM>' becomes unstable with the increased airflow and bounces around wildly and may strike the UAV, and there is the possibility of engagement with the rotors of the UAV. Therefore, when using a solid, smooth-walled payload coupling apparatus <NUM>', only a narrow range of air speeds from <NUM>-<NUM>/s are suitable to dampen the oscillations of the payload coupling apparatus. At air speeds in the range of <NUM>-<NUM>/s, depending on the UAV, this speed may be too slow for the UAV to be "on the wing" in full forward flight requiring that the hover motors of the UAV are still running, which increases energy consumption and reduces the range of the UAV.

Payload coupling apparatus <NUM> has the same hook and lip construction as a standard smooth-walled payload coupling apparatus <NUM>', but advantageously includes a series of perforations, or holes, in the major surfaces of the payload coupling apparatus <NUM>, as described above, which allow the payload coupling apparatus <NUM> to remain stable even at increased air speeds of <NUM>-<NUM>/s or more. The series of perforations or holes serve to stabilize the payload coupling apparatus <NUM> during retraction so that it remains in a stable state, without moving erratically (as is the case when using payload coupling apparatus <NUM>') during high speed UAV flight of <NUM>-<NUM>/s or more.

Wind tunnel testing has revealed that payload coupling apparatus <NUM> remains stable and does not move erratically or wildly at speeds of <NUM>-<NUM>/s or more, whereas at that speed, payload coupling apparatus <NUM>' swings about wildly and erratically, and is very unstable.

The symmetrically positioned holes extend through outer surfaces of the payload coupling apparatus <NUM> into a hollow interior of the payload coupling apparatus <NUM>. As a result, air is allowed to flow through the payload coupling apparatus <NUM>, i.e. through the holes on the hemispherically-shaped upper portion and through the holes in the upper and lower surfaces of the slot and hook or lip, during high speed flight, which allows for the payload coupling apparatus <NUM> to remain in a stable position during retraction as the UAV moves at full cruise speed of <NUM>-<NUM>/s or more.

In addition, as shown in <FIG> and <FIG>, a weighted disc <NUM> may be positioned within the payload coupling apparatus <NUM> to provide a "weight-forward" payload coupling apparatus <NUM> which contributes to increased high speed stability. Due to less material used for the payload coupling apparatus <NUM> as compared to payload coupling apparatus <NUM>' because of the holes, the disc <NUM> may add additional weight to the payload coupling apparatus <NUM> as compared to the weighted disc used in smooth-walled payload coupling apparatus <NUM>' (shown in <FIG>) so that a desired overall weight may be achieved that is the same as payload coupling apparatus <NUM>'.

Furthermore, the weighted disc <NUM> may have a centrally located aperture <NUM> that provides an aerodynamic influence on the payload coupling apparatus <NUM>. The size of the centrally located aperture <NUM> in the weighted disc may be adjusted so that the payload coupling apparatus <NUM> rides higher or lower in the air column during retraction as the UAV <NUM> moves at full cruise speed. Of course, one or more holes may also be positioned in weighted disc <NUM> which may or may not by symmetrical in terms of size or position. It is desirable for the payload coupling apparatus <NUM> to ride as low as possible in the air column so that it is further away from the UAV <NUM> during flight, thereby further reducing the chance of the payload coupling apparatus <NUM> coming into contact with the UAV <NUM> during flight.

The air flow around (or through) the payload coupling apparatus <NUM> is believed to actually be more turbulent than around smooth-walled payload coupling apparatus <NUM>'. The difference is that the turbulence on the payload coupling apparatus <NUM> is very uniform (lots of very small and weak vertices) in comparison to the turbulence around the smooth-walled payload coupling apparatus <NUM>'at higher speeds is random (with big and strong vortices). The uniformity of the turbulence is what helps to achieve the stable behavior in payload coupling apparatus <NUM>. In addition, further stability is also provided by having airflow that enters the payload coupling apparatus <NUM> in the front (through holes in upper portion <NUM>) partially redirected outward to the holes in side wall <NUM>. The air exiting the holes of the side wall creates an air cushion which makes the payload coupling apparatus behave like a "shuttlecock," resulting in greater stability during flight.

Using payload coupling apparatus <NUM> provides significant advantages in comparison to payload coupling apparatus <NUM>'. In particular, because the plurality of holes in payload coupling apparatus <NUM> provides for a stable payload coupling apparatus at speeds of <NUM>-<NUM>/s or more, once payload coupling apparatus <NUM> is disengaged from a payload at a payload delivery site, the UAV may immediately move into full forward flight of <NUM>-<NUM>/s or more. The payload coupling apparatus <NUM> may be retracted towards the UAV at the same time. As a result, the UAV does not have to fly at a reduced speed of <NUM>-<NUM>/s (as is the case when using payload coupling apparatus <NUM>') to have a stable payload coupling apparatus, and the hover motors are not needed. Because the hover motors can be turned off during retraction, less power is required and the overall safety is increased in the very unlikely event (because of the stability of payload coupling apparatus <NUM>) of contact between payload coupling apparatus <NUM> and hover props (e.g., due to a sudden air turbulence in cruise flight), there would be no damage to the hover propellers because they would not be rotating. In addition, less time is required following payload delivery as the payload coupling apparatus <NUM> is retracted because the UAV is able to move directly into full speed flight of <NUM>-<NUM>/s or more.

Furthermore, during winch up of a payload <NUM> to the UAV <NUM>, high winds may cause the payload <NUM> and payload coupling apparatus <NUM> to rotate. Once the payload coupling apparatus <NUM> reaches the UAV, it is drawn into a payload receptacle and cams within the payload receptacle engage with cams on the payload coupling apparatus to align the payload in a desired position. The engagement of the cams arrests the rotation of the payload coupling apparatus <NUM> and may cause the handle <NUM> of payload <NUM> to "spin itself out" of the slot in the payload coupling apparatus as payload <NUM> continues to rotate. In order to prevent the handle <NUM> from coming out of the slot under such conditions, as shown in <FIG>, a first indentation <NUM> is positioned on a left side of slot <NUM> in left side 806a of hook or lip <NUM> and a second indentation <NUM> is positioned on a right side of the slot <NUM> in right side 806b of hook or lip <NUM>. First indentation <NUM> and second indentation <NUM> arrest rotation of the handle <NUM> as the handle <NUM> gets caught in the indentations. Indentations <NUM> and <NUM> serve to prevent the handle <NUM> from "spinning itself out" of the slot <NUM> during rotation of payload <NUM> () caused by high winds during winch up. First and second indentations <NUM> and <NUM> may also be provided on smooth-walled payload coupling apparatus <NUM>' shown in <FIG>.

The particular arrangements shown in the Figures should not be viewed as limiting. It should be understood that other implementations may include more or less of each element shown in a given Figure. Further, some of the illustrated elements may be combined or omitted. Yet further, an exemplary implementation may include elements that are not illustrated in the Figures.

Claim 1:
A payload coupling apparatus (<NUM>) for coupling a payload (<NUM>) to an unmanned aerial vehicle, UAV, the payload coupling apparatus comprising:
a housing having an upper portion (<NUM>), a lower portion, and a side wall (<NUM>) positioned between the upper and lower portions;
an attachment point on the housing adapted for attachment to a first end of a tether (<NUM>); and
a slot (<NUM>) in the housing that extends downwardly towards a center of the housing thereby forming a hook or lip (<NUM>) on the lower portion of the housing beneath the slot,
wherein the payload coupling apparatus is characterized in that:
the payload coupling apparatus comprises a plurality of holes (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM><NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) in the upper portion of the housing, and a plurality of holes (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) in the lower portion of the housing;
the housing is hollow, and air is allowed to flow through the plurality of holes in the upper portion of the housing, through the housing, and exit the plurality holes in the lower portion of the housing; and
the housing is constructed with two pieces, wherein the two pieces of the housing include a right side (800b) and a left side (800a).