Unmanned aerial vehicle for mitigating electromagnetic interference

Abstract

An unmanned aerial vehicle (UAV) is provided. The UAV has an airframe providing an enclosure that is made of an electrically conductive material and that is sized to enclose at least one motor drive component. The airframe may have airframe parts that provide the enclosure and that are contiguous, each airframe part being electrically conductive. The enclosure may be integral with the airframe. The UAV may have a coupling that is configured to couple the motor and a propeller external to an area of the enclosure while maintaining an electromagnetic seal across the area. The UAV can be helpful in mitigating electromagnetic interference.

Description

UNMANNED AERIAL VEHICLE FOR MITIGATING ELECTROMAGNETIC INTERFERENCEFIELD

[0001] This application relates generally to unmanned aerial vehicles (UAV) and, more specifically, UAVs for mitigating electromagnetic interference.BACKGROUND

[0002] Sensors may be adapted as payloads for UAVs. However, many such sensors rely on electromagnetic transmission and reception. As a result, they are susceptible to electromagnetic emissions from the UAV itself.SUMMARY

[0003] According to an aspect of the disclosure, there is provided an unmanned aerial vehicle (UAV) comprising: an airframe providing an enclosure that is made of an electrically conductive material and that is sized to enclose at least one motor drive component.

[0004] In some embodiments, the airframe comprises a plurality of airframe parts that provide the enclosure and that are contiguous, each airframe part of the airframe parts being electrically conductive.

[0005] In some embodiments, the airframe parts are electrically bonded.

[0006] In some embodiments, the airframe parts are electrically bonded with a resistance of less than about 0.1 ohms.

[0007] In some embodiments, the UAV further comprises copper tape covering mating surfaces of the airframe parts.

[0008] In some embodiments, the enclosure is integral with the airframe.

[0009] In some embodiments, the enclosure is integral with a main body, a motor enclosure, or an arm supporting the motor enclosure to the main body, or any combination thereof.

[0010] In some embodiments, the UAV further comprises the at least one motor drive component, the at least one motor drive component comprising an electric motor, a speed controller, an electrical power source, and their wire interconnects.

[0011] In some embodiments, the enclosure being sized to enclose at least one motor drive component comprises the enclosure being sized to enclose a motor.

[0012] In some embodiments, the UAV further comprises a coupling that is configured to couple the motor and a propeller external to an area of the enclosure while maintaining an electromagnetic seal across the area.

[0013] In some embodiments, the area defines an aperture through which the coupling couples the motor and the propeller, and the coupling is electrically conductive and electrically connected to the area.

[0014] In some embodiments, a portion of the coupling overlaps a portion of the enclosure.

[0015] In some embodiments, the area defines an aperture through which the coupling couples the motor and the propeller, and the coupling is electrically non- conductive.

[0016] In some embodiments, the coupling is made of plastic.

[0017] In some embodiments, the UAV further comprises an electromagneticbased sensor disposed external to the enclosure, wherein the electrically conductive material is sufficiently electrically conductive to mitigate electromagnetic radiation from within the enclosure to the electromagnetic-based sensor in a range of operation of the electromagnetic-based sensor.

[0018] In some embodiments, the electrically conductive material is made of metal.

[0019] In some embodiments, the metal is solid aluminum.

[0020] In some embodiments, the electrically conductive material is made of conductive polymer.

[0021] According to another aspect of the disclosure, there is provided a computer readable medium storing instructions executable by one or more processors to control an additive manufacturing apparatus to manufacture the UAV as described herein.

[0022] According to another aspect of the disclosure, there is provided a method of manufacturing a device via additive manufacturing, the method comprising:obtaining an electronic file representing a geometry of a product, wherein the product is a UAV as described herein; and controlling an additive manufacturing apparatus to manufacture, over one or more additive manufacturing steps, the product according to the geometry represented in the electronic file.

[0023] Other aspects and features of the disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Embodiments of the disclosure will now be described in greater detail with reference to the accompanying drawings, in which:

[0025] FIG. 1A illustrates a top view of an exemplary shielded UAV according to one or more embodiments;

[0026] FIG. 1 B illustrates a perspective view of the exemplary shielded UAV of FIG. 1A;

[0027] FIG. 2A illustrates a side view of a portion of a main body of the shielded UAV of FIG. 1A and FIG. 1 B;

[0028] FIG. 2B illustrates another side view of the main body of the shielded UAV of FIG. 1A and FIG. 1 B;

[0029] FIG. 3 illustrates a perspective view of a wiring enclosure and a motor enclosure of the shielded UAV of FIG. 1 A and FIG. 1 B;

[0030] FIG. 4 illustrates a front view of the motor enclosure of the shielded UAV;

[0031] FIG. 5 illustrates a top view of a motor enclosure lid of the shielded UAV;

[0032] FIG. 6 illustrates a cross-sectional view of the motor enclosure of the shielded UAV;

[0033] FIG. 7A shows graphical results of testing the shielded UAV for electromagnetic emissions;

[0034] FIG. 7B shows more graphical results of testing the shielded UAV for electromagnetic emissions.

[0035] FIG. 8 illustrates a cross-sectional view of a coupling of the motor enclosure;

[0036] FIG. 9 shows a photograph of a shielded UAV according to one or more embodiments;

[0037] FIG.10 shows a photograph of the motor enclosure and coupling of the shielded UAV of FIG. 9;

[0038] FIG. 11 shows a photograph of an inside of a main body of the shielded UAV of FIG. 9; and

[0039] FIG. 12 shows another cross-sectional view of the motor enclosure with another coupling.DETAILED DESCRIPTION

[0040] Investigations into various challenges and methods of mitigating electromagnetic interference were conducted.

[0041] In the case of explosive threat sensors, such as handheld metal detectors, the sensors are used to locate explosive threats including mines, unexploded ordnance, and improvised threats. The sensors generally require an operator to approach and work in close proximity to the explosive threat at great risk to the operator. If proven counter explosive threat sensors can be adapted as payloads on UAVs, the sensors may be employed remotely, allowing a large distance between the operator and the explosive threat to be maintained without loss of performance of the sensor and reducing the risk to the operator.

[0042] Many explosive threat sensors rely on electromagnetic transmission and reception, rendering them susceptible to electromagnetic emissions or radiofrequency interference from the UAV itself. These emissions interfere with the operation of an explosive threat sensor payload, particularly in the low to intermediate frequency range (100 kHz up to several tens of MHz) and may reduce the performance of the explosive threat sensor payload.

[0043] For some sensors, such as optical or high-frequency (multi-GHz) ground penetrating radar, the directional nature of the electromagnetic waves can be used to mitigate or eliminate interference. For lower frequency or static field sensors this is not the case, and large distances between the sensor and UAV can be used to mitigate interference. For example, there are some UAVs that have been equipped with static magnetic field sensors, such as magnetometers, where the sensor is suspended by along cable. The distance between the sensor and the UAV prevents electromagnetic interference. However, this approach is not applicable to all explosive threat sensors.

[0044] Intermediate frequency (100 kHz to several tens of MHz) sensors operate in a frequency range that overlaps directly with observed UAV emissions frequencies, and thus, mitigating interference is difficult. The strategy of increasing distance between the sensor and the UAV has been employed for very low frequency sensors. They are suspended from the UAV by long cables, typically several meters in length. This significantly changes the flight dynamics of the UAV and is not compatible with positioning requirements of some sensors. Specifically, some sensors require precise positioning while scanning to enable detection and clearance of large areas, and the swinging motion of the sensor, as introduced by suspension on a cable, would obviate accurate positioning. The introduction of a long conductive cable also increases generated electromagnetic emissions and directly interferes with sensors that are designed to detect conductors.

[0045] Electromagnetically quiet UAV identification and selection, component selection (i.e., some components generate more electromagnetic emissions than others), electronic filtering, and shielding were considered for mitigating electromagnetic interference. UAV system and component level measurements showed that electric powered UAVs (i.e., those that use batteries for power) emit electromagnetic radiation across a frequency band of 100 kHz to several tens of MHz. In some cases, a different fuel source, such as nitromethane, may be used resulting in the UAV (for example, a small radio-controlled helicopter) being relatively noise free, however there were drawbacks associated with such a fuel source that precluded its use. In UAVs, emissions originated from electrical components associated with driving motors (motors, wire interconnects, and driving electronics such as electronic speed controllers, and batteries), which may be considered as forming a motor chain. This was due to the large time-varying currents (for example, 10s of amps) required to drive the motors. This was exacerbated by the pulse-width modulation scheme that all speed controllers use to convert DC battery power into sinusoids that are used to drive 3-phase motors (the speed controller produces by far the most noise due to high driving currents being passed through it). As such, neither UAV nor specific component selection resulted in an electromagnetic emission free UAV. Furthermore, filtering was difficult as the currents were large, and filtering would only confine noiseto portions of the electrical components but would not be sufficient to eliminate the electromagnetic emissions.

[0046] Embodiments of the UAV are now described in more detail with reference to the drawings.

[0047] Referring to FIG. 1 A and FIG 1 B, there is provided a UAV in accordance with one or more embodiments. The UAV is generally identified with reference numeral 100. The UAV 100 comprises an airframe 110. The airframe 110 provides an enclosure 115 that is made of an electrically conductive material and that is sized to enclose at least one motor drive component. In use, when the UAV 100 is equipped with motor drive components, electromagnetic radiation from the UAV may be mitigated by enclosing the components in the enclosure 115. When the UAV 100 is further equipped with a sensor 140 that is electromagnetic based and that is disposed outside the UAV, electromagnetic interference with the sensor may be mitigated.

[0048] In the embodiment shown, the enclosure 115 is integral with the airframe 110. Thus, the shielding uses the structure of the UAV itself.

[0049] In some embodiments, the enclosure 115 may be attached to the airframe 110, such as by layering. The enclosure 115 may be of any shape.

[0050] The electrically conductive material may be made of metal or conductive polymer. Aluminum shielding may be incorporated into the airframe itself to reduce overall mass of the UAV, in lieu of having an airframe with an added shield. In comparison to copper, aluminum has significantly lower density while maintaining a high conductivity.

[0051] In the embodiment shown in FIG. 1A and FIG. 1 B, the airframe 110 includes airframe parts that provide the enclosure, are contiguous, and are electrically conductive. They may be electrically bonded to one another. In the embodiment shown, the airframe 110 includes a main body 120, a plurality of arms 125 extending from the main body 120 at one end, and a motor enclosure 130 at the other end of each of the arms 125, and the enclosure 115 is integral with these airframe parts. The enclosure 115 may be sized to enclose at least one component of a motor drive (system that includes a motor), such as a speed controller, an electric motor, an electrical power source (for example, a battery), their wire interconnects (for example, high-current wires), and flight controller (not shown). The enclosure 115 may, entirelyor substantially, enclose all motor drive components electrical components associated with driving motors. The enclosure 115 prevents electromagnetic emission from the electrical components interfering with a sensor 140, electromagnetic based, which is coupled to the main body 120. In some embodiments, the airframe is constructed as one-piece, instead of being made of airframe parts.

[0052] Each motor enclosure 130 houses a motor which is connected to a corresponding propeller 135. The motor enclosures provide shielding near rotating blades. The motors are inside the shielding enclosure, while the propellers are outside to allow flight. Each arm 125 houses wiring connecting each motor to the electrical components in the main body 120, such as speed controller signals. The arms 125 being of a conductive material provide a shielded zone for wire interconnects between the speed controllers and the motors. The electrical components, the motors, and the wiring are all internal to the airframe 110. The propellers 135 are external to the airframe 110. The sensor 140 may be any type of sensor including, but not limited to, an explosive threat sensor or a magnetic field sensor, for example.

[0053] In order to contain the electromagnetic emissions from the electrical components, the airframe 110 may be made of a high-conductivity material, such as aluminium which has a conductivity of 3.5x107Srrr1. By constructing the airframe 110 from the high-conductivity material, an enclosure is created that prevents the electromagnetic emissions from escaping the airframe 110. All electrical components and wiring may be enclosed within the airframe 110 to ensure that no electromagnetic emissions are transmitted beyond the airframe 110.

[0054] Additional mitigation strategies include twisting of electrical leads and adding copper tape to improve electrical contacts on portions of the shielding, such as mating surfaces.

[0055] Although the airframe 110 is described as being made of aluminium as an exemplary high-conductivity material, other configurations are possible. For example, the airframe 110 may be made of or incorporate copper meshes, solid copper, copper tape, ora high-permeability alloy. Solid copper tape provides excellent shielding for its mass. The airframe 110 may be solid aluminum due to its high conductivity, low density (compared to copper), and rigidity. High-conductivity materials (i.e., copper and aluminum) rely on reflection and absorption as waves passthrough the material. Alternatively, the airframe 110 may include a skeleton frame made of plastic, carbon fibre, or other non-conductive material provided the electrical components are enclosed in a conductive material. The conductive material that is used to create the airframe 110 may be of varying thickness, however having a thin airframe 110 may impact on the mechanical strength of the UAV 100. A hybrid design (plastic skeleton with metal tubes, a central metal chamber, and metal motor boxes) could be considered.

[0056] The airframe 110 may be made of a conductive polymer, for example a conductive polymer used in 3D printing. These materials have a lower electrical conductivity (in the region of 1000 Srrr1or less, so approximately 10,000 times lower than aluminum). As such, a conductive polymer may not shield effectively in the desired frequency range (100 kHz to several tens of MHz). However, it may shield adequately at much higher frequencies that are relevant to other sensor modalities including, for example, ground penetrating radar in a range between about 10 MHz to 3 GHz, and in some cases beyond 3 GHz.

[0057] Although the airframe 110 is described as having six arms 125, each with a motor enclosure 130 and a propeller 135, other configurations are possible. In other embodiments, the airframe 110 may not have arms 125 extending from the main body 120. The main body 120 may contain all electrical components, wiring, and the motor, with the propeller 135 connected to the motor external to the main body 120.

[0058] The airframe 110 may be of a different shape (i.e. , a central square or hexagon), as long as the chamber completely encloses all components and there are no seams that break electrical contact. The arms 125 may be of any shape, such as tubing with a round cross-section or tubing with a square cross-section, for example. The UAV 100 may include a single motor with a single corresponding propeller 135. The UAV 100 may include any number of motors with corresponding propellers 135. Some embodiments have no wires protruding, as this can carry signals out of the chamber. A GPS receiver may be mounted to the outside and bring a signal to the flight controller inside the airframe, however, which may require filtering or additional shielding. Alternatively, a portion of the airframe may be shielded to mitigate propagation of electromagnetic radiation in the direction of the sensor 140. In some cases, partial shielding of the airframe 110 may be effective, however the effectiveness will depend on the frequency of interest.

[0059] Although, FIG. 1A and FIG. 1 B show the propellers 135 on the UAV 100 being arranged alternately on an upper side and on a lower side of the UAV 100, other configurations of the propellers 135 are possible. For example, the propellers 135 may all be positioned on a same side of the UAV 100 such as on the upper side.

[0060] Referring now to FIG. 2A, a section of the main body 120 is shown. The main body 120 has several side walls 210 that are coupled together. Each side wall 210 includes a plurality of apertures 220 in a lateral direction for coupling upper and lower portions to the main body 120. Each side wall 210 has an opening 230 positioned generally on a central axis 232 of the side wall 210 for accommodating wiring from the electrical components housed in the main body 120 through an arm 125 to the motor. Circumscribing the large opening 230 are several smaller apertures 235 for coupling the arm 125 to the main body 120.

[0061] Referring now to FIG. 2B, an upper portion 240 and a lower portion 245 are attached to the side walls 210 with fasteners 247. The fasteners 247 may be threaded fasteners such as bolts with nuts, or screws, or may be rivets. The fasteners 247 attach the upper portion 240 and the lower portion 245 to each side wall 210 through the apertures 220. The upper portion 240 and the portion 245 have aligning apertures (not shown) to accommodate the fasteners 247. In some cases, the side walls 210 may be of unitary construction. In some cases, the main body 120 may be of unitary construction, or may have only one attachable portion.

[0062] Referring now to FIG. 3, a single arm 125 of the airframe 110 of the UAV 100 in FIG. 1A and FIG. I B with a motor enclosure 130 is shown. The arm 125 includes a boom 310 coupling to an adapter 320 on the motor enclosure 130. A flange 315 at each end of the boom 310 couples to the main body 120 and to an adapter 320 for coupling to the motor enclosure 130. The motor enclosure 130 may be generally cuboid in shape, however the shape of the motor enclosure 130 may vary. The adapter 320 may be generally cuboid in shape and may be smaller than the motor enclosure 130. The adapter 320 is on a front face 325 of the motor enclosure 130. The motor enclosure 130 has a lid 330 to allow access to the motor within the motor enclosure 130. The motor enclosure 130 includes a coupling 340 that couples the motor and the propeller 135 so that the propeller 135 may rotate while containing electromagnetic emissions from the motor and electrical components within the airframe 110 and motor enclosure 130. The propeller 135 is attached to the coupling 340 by fasteners 345.

[0063] The flanges 315 have several apertures 317 through which fasteners 319 are received to attach the arm 125 to the main body 120 and the adapter 320. The fasteners 319 attach the flange to the main body 120 through the smaller apertures 235 on the main body 120 side wall 210. The fasteners 319 may be threaded fasteners such as screws or bots, or rivets or similar.

[0064] Referring now to FIG. 4, a front view of the adapter 320 is shown. The adapter 320 has an opening 410 positioned generally central on a front 412 of the adapter 320 for accommodating wiring running through an arm 125 to the motor. Circumscribing the opening 410 are several smaller apertures 415 for coupling the arm 125 to the front 412 of the adapter 320 with fasteners 317.

[0065] Referring now to FIG. 5, a top view of the motor enclosure 130 lid 330 is shown. The lid 330 includes several apertures 510 for coupling the lid 330 to the motor enclosure 130. The lid 330 may be coupled to the motor enclosure 130 with fasteners 247 that pass through the apertures 510 into aligning openings (not shown) in the motor enclosure 130. In a generally central position in the lid 330 is a coupling opening 520 through which the coupling 340 is received.

[0066] The airframe parts that comprise the airframe 110 may be electrically connected. A bonding resistance between any two components, such as between an arm 125 and the main body 120 or between an arm 125 and a motor enclosure 130, may be less than about 0.1 ohms. A suitable bonding method or material may be used, including for example, straight aluminum to aluminum bonding, sanded aluminum contacts, etched aluminum to etched aluminum bonding, conductive silver paint, conductive silver epoxy, and copper tape. Etched aluminum to etched aluminum bonding may be used, however, copper tape provides improved reliability for joints that are disassembled frequently. For permanent joints, direct welding may be used. In some cases, a plating method may be used.

[0067] The motor enclosure 130 mitigates the electromagnetic emissions produced by the motor, but also allows the motor to act on the propeller 135 to achieve flight. The motor enclosure 130 can be electrically connected to the rest of the airframe 110. The coupling 340 connects the propeller 135 to the motor through the lid 330. The lid 330 is electrically connected to the motor enclosure 130 and the remainder of the airframe 110. The lid 330 is electrically connected to the airframe 110 to ensurecontainment of the electromagnetic emissions. Coupling fasteners 345, such as screws or similar, attach the propeller 135 to the output of the motor so that as the motor turns, the propeller 135 turns. The coupling 340 also rotates. An example of the motor enclosure 130 is illustrated in FIG. 6, discussed further below.

[0068] Overlapping, but not physically nor electrically contacting, metal parts trap the electromagnetic emissions of the motor and other components. This was demonstrated for magnetic fields in the near-field (within several wavelengths of the source), as shown by the data in FIG 7A and FIG 7B, which provides graphical results of testing the shielded UAV for electromagnetic emissions. However, it was determined that this is not true for electric fields in the near-field, as measurements of the electric field showed some emissions (albeit improved compared to no shielding at all).

[0069] In some embodiments, the coupling 340 is made of an electrically conductive material. The coupling fasteners 345 may also be of an electrically conductive material. The coupling 340, when made of an electrically conductive material, is electrically connected (e.g., bonded) to the airframe 110 to mitigate electromagnetic emissions from the airframe 110. The coupling 340 may be electrically connected to the airframe 110 by a bearing or gasket system (not shown) mounted on the lid 330. For example, physical brushes that contact both the coupling 340 and the lid 330 may be used to achieve the electrical connection. The electrical connection may ensure that the coupling is at the same potential as the airframe 110.

[0070] In some embodiments, a magnetic bearing system, where torque from the motor is coupled to the propeller 135 through the lid 330 using magnetic fields may be used. Such bearing systems are heavy, and any gains in shielding performance come with added weight. If the coupling 340 and the lid 330 are in contact, friction is added to the rotating motor which may be detrimental to performance.

[0071] Referring now to FIG. 8, a cross-sectional view of the coupling 340 is shown. The coupling 340 is generally cylindrical in shape, having one or more vias 610 through which the coupling fasteners 345 are received. The coupling has a lip 620 extending laterally at one end. The lip 620 overlaps the lid 330 at the coupling opening 520. The coupling 340 has a central channel 810 to accommodate a drive shaft component of the motor. The coupling has a portion that overlaps the area and that isfree from contact with the area. For example, the coupling 340 may be shaped like a “top-hat” feedthrough and connect the propeller to the motor through the motor enclosure 130. The mechanical feedthrough coupling relies on electrical contact between the coupling 340 and the motor enclosure 130.

[0072] The motors drive the propellers 135 that provide thrust for flight, and the propellers 135 themselves cannot be enclosed. However, the motors, which are a significant source of electromagnetic noise, may be enclosed. The coupling 340 traps electromagnetic noise inside the motor enclosure 130, but still allows mechanical connection, from the motor to outside the motor enclosure 130, to the propellers 135. The motor enclosure 130 substantially encloses the motor but provides feedthroughs that connect the enclosed motor to propellers 135 outside the enclosure. The coupling 340 couples the motor and a propeller 135 external to an area of the motor enclosure 130 while maintaining an electromagnetic “seal” across the area. The electromagnetic seal may be characterised by a good electrical contact with a resistance of less than 0.1 Ohms. The electromagnetic seal may be formed by electrically connecting the coupling 340 to the motor enclosure 130. The aperture 520 through which the coupling 340 couples the motor and the propeller 135, and the coupling 340 is electrically conductive and electrically bonded to the area. In particular, the structure of the coupling 340 allows mechanical connection and motor motion, but also maintains the electromagnetic seal with the electrical connection. Brushes or some other mechanism can be used to ensure electrical contact between the coupling 340 and the motor enclosure 130. Absent an electrical connection between the coupling 340 and the motor enclosure 130, the reduction of interference will be decreased.

[0073] Referring now to FIG. 6 a cross-sectional view of the motor enclosure 130 is shown. The coupling fasteners 345 attach the propeller 135 to a drive shaft 630 of the motor so that as the drive shaft 630 rotates, the coupling 340 and the propeller 135 rotate. The drive shaft 630 is received within the central channel 810 of the coupling 340. In this example, the coupling 340 overlaps the lid 330 internal of the motor enclosure 130. The coupling 340 connects the motor (not shown) to its propeller 135 through the lid 330 of the motor enclosure 130. The coupling fasteners 345 attach the propeller 135 to the motor through the vias 610 in the coupling 340. The aperture 520 in the motor enclosure 130 defines an area through which the coupling 340 couples the motor and the propeller 135.

[0074] In some embodiments, the coupling 340 is made of an electrically non- conductive material, such as plastic. The coupling fasteners 345 may also be made of an electrically non-conductive material. If the coupling 340 and coupling fasteners 345 are made of an electrically non-conductive material, interference may be reduced, and the overall weight of the UAV 100 may be reduced. A bearing or gasket system is not required for a non-conductive coupling 340. For example, the coupling 340 may be made of plastic and the motor enclosure 130 of metal, according to one arrangement. The coupling’s 340 central cylinder 810 connects to the propeller, but the lip 620 overlaps (without physical contact with the motor enclosure 130 as it rotates with the motor) with the lid 330 to prevent electromagnetic noise from escaping. The gap between the lip 620 and the lid 330 may be minimized. To provide an electromagnetic seal that mitigates electric and magnetic fields from being emitted, the coupling 340 is configured to prevent fields from escaping. As discussed above, the coupling 340 may be made of an electrically conductive material in electrical connection with the airframe 110, or the coupling 340 may be made of an electrically non-conductive material.

[0075] Referring now to FIG. 7A, results of testing the shielding of the UAV 100 are shown in graph 700. Graph 700 shows the results of testing one arm 125 of the UAV 100 for electromagnetic emissions in dBuA / m plotted against frequency in MHz. The scale of the y-axis is logarithmic. The testing was performed for the frequency range of 100 kHz to 4 MHz. One arm 125 was tested to simplify experimentation to help quantify emission mitigation strategies. The motor of the arm 125 was affixed to a test platform and operated with and without shielding. For the case with shielding, the arm 125, including the motor enclosure 130, and the main body 120 were held to the test platform. For the case without shielding, the motor and all other UAV components were fixed to the test platform in the same positions as with the case with shielding. In FIG. 7A, a first trace 710 represents the case without shielding, and a second trace 720 represents the case with shielding. A background trace 730 represents baseline background electromagnetic radiation that is the minimum level of electromagnetic emissions that may be measured by the experimental equipment. Electromagnetic emissions were reduced by approximately 40 dB (or four orders of magnitude) across the frequency band monitored. The electromagnetic emissions may be restricted into the background trace 730 level.

[0076] Referring now to FIG. 7B, results of testing the shielding of the UAV 100 are shown in graph 750. Graph 750 shows the results for testing the shielding of six arms 125 of the UAV 100 for the electromagnetic emissions in dBuA / m plotted against frequency in MHz. The scale of the y-axis is logarithmic. The testing was performed for the frequency range of 100 kHz to 4 MHz. The case without shielding was not tested for the UAV 100 with multiple arms 125 given the complexities in setting up multiple unattached motors on the test platform. In graph 750, a first trace 760 represents the case with shielding. The background trace 730 represents baseline background electromagnetic radiation. Electromagnetic emissions were significantly reduced, to below the noise floor, for the majority of the frequency band monitored. In addition to the shielding, wiring to the motor was twisted (for example, in a three-strand braid) and copper tape was added to joints in the airframe parts to improve the electrical connections.

[0077] Further information relating to testing electromagnetic emissions from UAVs is described in S.E. Irvine et al., “System and Component Level Measurements of the Electromagnetic Emissions of Unmanned Aerial Vehicles” (June 2023) Document No. DRDC-RDDC-2023-R046, online: Canadian Defence Information Database - CANDID <https: / / cradpdf.drdc- rddc.gc.ca / PDFS / unc430 / p816780_A1 b.pdf>, incorporated herein by reference.

[0078] Referring now to FIG. 9, a photograph of a shielded UAV 900 is provided. The UAV 900 is generally similar to the UAV 100. The UAV 900 includes an airframe 910. The airframe 910 includes a main body 920, a plurality of arms 925 extending from the main body 920 at one end, and a motor enclosure 930 at the other end of each of the arms 925. Although the embodiment in FIG. 1A and FIG. 1 B shows each propeller 135 as having a pair of blades, other configurations are possible. For example, the UAV 900 is shown with propellers 935, each having three blades. The alternating arrangement of propellers 935 being in an upward facing orientation and in a downward facing orientation is shown, however in some embodiments the propellers 935 may all be in the same orientation. Conductive tape 950 is applied where the arms 925 are coupled to the main body 920. The conductive tape 950 may be, for example, copper tape.

[0079] Referring now to FIG. 10, a photograph of the motor enclosure 930 of the UAV 900 is shown. The motor enclosure 930 includes a coupling 940. The coupling940 is made of plastic and couples the propeller 935 to the motor inside the motor enclosure 930. As the motor inside the motor enclosure 930 rotates, the coupling 940 and the propeller 935 rotate. The seams of the motor enclosure 930 are reinforced with the conductive tape 950 to further improve the shielding of the UAV 900.

[0080] Referring now to FIG. 11 , a photograph of the inside of the main body 920 of the UAV 900 is shown. The main body 920 contains electronic components and wiring 960. The electronic components and wiring 960 include, for example, batteries 962 and three strand braided wire 964. The electronic components (motors, motor wires, motor driving electronics) and wiring 960 emit electromagnetic radiation while in operation and are sealed within the main body 920 and remainder of the UAV 900 to prevent the electromagnetic radiation from escaping the UAV 900 and interfering with operation of the sensor 140.

[0081] Referring now to FIG. 12, a cross-sectional view of the motor enclosure 130 is shown. A coupling 1340 is generally cylindrical and attaches the propeller 135 to the drive shaft 630 of the motor so that as the drive shaft 630 rotates, the coupling 1340 and the propeller 135 rotate. The coupling fasteners 345 attach the propeller 135 to a drive shaft 630. The drive shaft 630 is received within a central channel 1810 of the coupling 1340. In this example, the coupling 1340 does not overlap the lid 330 internal of the motor enclosure 130.

[0082] Similar to the coupling 340, the coupling 1340 may be made of a conductive material. The coupling fasteners 345 may also be of a conductive material. The coupling 1340, when made of a conductive material, is electrically connected (e.g., bonded) to the airframe 110 to ensure that the electromagnetic emissions are not emitted from the airframe 110. The coupling 1340 may be electrically connected to the airframe 110 by a bearing or gasket system (not shown) mounted on the lid 330. For example, physical brushes that contact both the coupling 1340 and the lid 330 may be used to achieve the electrical connection.

[0083] The coupling 1340 connects the motor (not shown) to its propeller 135 through the lid 330 of the motor enclosure 130. The coupling fasteners 345 attach the propeller 135 to the motor through the vias 610 in the coupling 1340. The aperture 520 in the motor enclosure 130 defines an area through which the coupling 1340 couples the motor and the propeller 135.

[0084] Similar to the coupling 340, the coupling 1340 may be made of an electrically non-conductive material, such as plastic. The coupling fasteners 345 may also be of a non-conductive material. If the coupling 1340 and coupling fasteners 345 are non-conductive, interference may be reduced, and the overall weight of the UAV 100 may be reduced. A bearing or gasket system is not required for a non-conductive coupling 1340. For example, the coupling 1340 may be made of plastic and the motor enclosure 130 of metal, according to one arrangement.

[0085] As described herein, in order to contain electromagnetic emissions from the electrical components of the UAV 100, the components may not be allowed to emit unwanted electromagnetic signals outside of the UAV 100. In some embodiments, the UAV 100 has all electrical components enclosed within a contiguous conductive airframe 110, the motors transferring torque from inside the airframe 110 to the propeller or propellers 135 external to the airframe 110, and in the case where the airframe 110 comprises several different components (such as arms 125 and motor enclosures 130), the different components may be electrically connected. If the coupling 340 that facilitates the transfer of torque from the motor to the propeller 135 is conductive, the coupling 340 may be electrically connected to the airframe 110. An alternative coupling 340 may be used that is non-conductive. The coupling fasteners 345 (for example, of nylon) in this case may also be non-conductive, which does not conduct the electromagnetic emissions through the airframe 110. In some embodiments, the UAV 100 may incorporate quieter components and / or filtering but will still benefit from shielding.

[0086] The UAV 100 may include a sensor, an electromagnetic based, disposed external to the enclosure. The electrically conductive material may be sufficiently electrically conductive to mitigate electromagnetic radiation from within the enclosure to the sensor in a range of operation of the sensor.

[0087] Explosive threat sensors often rely on the transmission and reception of radio frequency (RF) waves. Example explosive threat sensors that could be adapted as payloads on a shielded UAV 100 include metal detectors. The shielded UAV 100 may also have implications for sensors that operate at lower or higher frequencies than the frequency band of interest described herein, including ground-penetrating radar, or magnetometry. The UAV limited electromagnetic emissions in the band from 100 kHz to approximately 4 MHz, but the frequency range could extend higher.

[0088] The shielded UAV has little or no electromagnetic emissions so that various sensors, especially those that are electromagnetic based, may be integrated with the UAV. Reducing or eliminating electromagnetic emissions mitigates electronic interference between the UAV and sensors’ payload, which in turn allows operation of both the UAV and sensors without affecting performance of either. This will allow the sensor to be flown remotely. In terms of commercial applications, this may be relevant to sensors that require minimal interference while being operated. For example, some geological survey equipment requires little or no interference as they rely on sensitive measurement of disturbances in the Earth’s magnetic field. Other techniques, including buried utility detection, also relies on low-frequency (<1 MHz) modalities that would be susceptible to interference generated by UAVs. The shielded UAV may be designed for sensors related to military search.

[0089] Embodiments have been described in terms of rotary-winged aircrafts but may be used in fixed-wing aircrafts.

[0090] As will be appreciated by those of skill in the art, the embodiments discussed herein may be injection molded, blow molded or extrusion corrugated as individual parts and then assembled.

[0091] Embodiments may be formed using an additive manufacturing process. A common example of additive manufacturing is three-dimensional (3D) printing; however, other methods of additive manufacturing are available. Rapid prototyping or rapid manufacturing are also terms which may be used to describe additive manufacturing processes.

[0092] As used herein, “additive manufacturing” refers generally to manufacturing processes wherein successive layers of material(s) are provided on each other to “build-up” layer-by-layer or “additively fabricate”, a three-dimensional component. This is compared to some subtractive manufacturing methods (such as milling or drilling), wherein material is successively removed to fabricate the part. The successive layers generally fuse together to form a monolithic component which may have a variety of integral sub-components. In particular, the manufacturing process may allow an example of the disclosure to be integrally formed and include a variety of features not possible when using prior manufacturing methods.

[0093] Additive manufacturing methods described herein enable manufacture to any suitable size and shape with various features which may not have been possible using prior manufacturing methods. Additive manufacturing can create complex geometries without the use of any sort of tools, molds or fixtures, and with little or no waste material. Instead of machining components from solid billets of plastic or metal, much of which is cut away and discarded, the only material used in additive manufacturing is what is required to shape the part.

[0094] Suitable additive manufacturing techniques in accordance with the present disclosure include, for example, Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjets and laserjets, Sterolithography (SLA), Direct Selective Laser Sintering (DSLS), Electron Beam Sintering (EBS), Electron Beam Melting (EBM), Laser Engineered Net Shaping (LENS), Electron Beam Additive Manufacturing (EBAM), Laser Net Shape Manufacturing (LNSM), Direct Metal Deposition (DMD), Digital Light Processing (DLP), Continuous Digital Light Processing (CDLP), Direct Selective Laser Melting (DSLM), Selective Laser Melting (SLM), Direct Metal Laser Melting (DMLM), Direct Metal Laser Sintering (DMLS), Material Jetting (MJ), NanoParticle Jetting (NPJ), Drop On Demand (DOD), Binder Jetting (BJ), Multi Jet Fusion (MJF), Laminated Object Manufacturing (LOM) and other known processes.

[0095] The additive manufacturing processes described herein may be used for forming components using any suitable material, subject to the above discussion regarding materials. For example, the material may be plastic, metal, composite, concrete, ceramic, polymer, epoxy, photopolymer resin, or any other suitable material that may be in solid, liquid, powder, sheet material, wire, or any other suitable form or combinations thereof. More specifically, according to exemplary embodiments of the present subject matter, the additively manufactured components described herein may be formed in part, in whole, or in some combination of materials including but not limited to pure metals, nickel alloys, chrome alloys, titanium, titanium alloys, magnesium, magnesium alloys, aluminum, aluminum alloys, iron, iron alloys, stainless steel, and nickel or cobalt based superalloys (e.g., those available under the name Inconel® available from Special Metals Corporation). These materials are examples of materials suitable for use in additive manufacturing processes which may be suitable for the fabrication of examples described herein.

[0096] As noted above, the additive manufacturing process disclosed herein allows a single component to be formed from multiple materials. Thus, the examples described herein may be formed from any suitable mixtures of the above materials. For example, a component may include multiple layers, segments, or parts that are formed using different materials, processes, and / or on different additive manufacturing machines. In this manner, components may be constructed which have different materials and material properties for meeting the demands of any particular application. In addition, although the components described herein are constructed entirely by additive manufacturing processes, it should be appreciated that in alternate embodiments, all or a portion of these components may be formed via casting, machining, and / or any other suitable manufacturing process. Indeed, any suitable combination of materials and manufacturing methods may be used to form these components.

[0097] Additive manufacturing processes typically fabricate components or assemblies based on 3D information, for example a three-dimensional computer model (or design file), of the components or assemblies.

[0098] Accordingly, examples described herein not only include products or components as described herein, but also methods of manufacturing such products or components via additive manufacturing and computer software, firmware or hardware for controlling the manufacture of such products via additive manufacturing.

[0099] The structure of one or more parts of the product may be represented digitally in the form of a design file. A design file, or computer aided design (CAD) file, is a configuration file that encodes one or more of the surface or volumetric configuration of the shape of the product. That is, a design file represents the geometrical arrangement or shape of the product.

[0100] Design files can take any now known or later developed file format. For example, design files may be in the Stereolithography or “Standard Tessellation Language” (. stl) format, which was created for stereolithography CAD programs of 3D Systems, or the Additive Manufacturing File (.amf) format, which is an American Society of Mechanical Engineers (ASME) standard that is an extensible markuplanguage (XML) based format designed to allow any CAD software to describe theshape and composition of any three-dimensional object to be fabricated on any additive manufacturing printer.

[0101] Further examples of design file formats include AutoCAD (.dwg) files, Blender (.blend) files, Parasolid ( x_t) files, 3D Manufacturing Format (,3mf) files, Autodesk (3ds) files, Collada (.dae) files and Wavefront ( obj) files, although many other file formats exist.

[0102] Design files can be produced using modelling (for example, CAD modelling) software and / or through scanning the surface of a product to measure the surface configuration of the product.

[0103] Once obtained, a design file may be converted into a set of computer executable instructions that, once executed by a processor, cause the processor to control an additive manufacturing apparatus to produce a product according to the geometrical arrangement specified in the design file. The conversion may convert the design file into slices or layers that are to be formed sequentially by the additive manufacturing apparatus. The instructions (otherwise known as geometric code or “G-code”) may be calibrated to the specific additive manufacturing apparatus and may specify the precise location and amount of material that is to be formed at each stage in the manufacturing process. As discussed above, the formation may be through deposition, through sintering, or through any other form of additive manufacturing method.

[0104] The code or instructions may be translated between different formats, converted into a set of data signals and transmitted, received as a set of data signals and converted to code, stored, etc., as necessary. The instructions may be an input to the additive manufacturing system and may come from a part designer, an intellectual property (IP) provider, a design company, the operator, or owner of the additive manufacturing system, or from other sources. An additive manufacturing system may execute the instructions to fabricate the product using any of the technologies or methods disclosed herein.

[0105] Design files or computer executable instructions may be stored in a (transitory or non-transitory) computer readable storage medium (for example, memory, storage system, etc.) storing code, or computer readable instructions, representative of the product to be produced. As noted, the code or computerreadable instructions defining the product that can be used to physically generate the object, upon execution of the code or instructions by an additive manufacturing system. For example, the instructions may include a precisely defined 3D model of the product and can be generated from any of a large variety of well-known computer aided design (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3D Max, etc. Alternatively, a model or prototype of the component may be scanned to determine the three-dimensional information of the component.

[0106] Accordingly, by controlling an additive manufacturing apparatus according to the computer executable instructions, the additive manufacturing apparatus can be instructed to print out one or more parts of the product. These can be printed either in assembled or unassembled form. For instance, different sections of the product may be printed separately (as a kit of unassembled parts) and then subsequently assembled. Alternatively, the different parts may be printed in assembled form.

[0107] In light of the above, embodiments include methods of manufacture via additive manufacturing. This includes the steps of obtaining a design file representing the product (i.e., the UAV) and instructing an additive manufacturing apparatus to manufacture the product in assembled or unassembled form according to the design file. The additive manufacturing apparatus may include a processor that is configured to automatically convert the design file into computer executable instructions for controlling the manufacture of the product. In these embodiments, the design file itself can automatically cause the production of the product once input into the additive manufacturing device. Accordingly, in this embodiment, the design file itself may be considered computer executable instructions that cause the additive manufacturing apparatus to manufacture the product. Alternatively, the design file may be converted into instructions by an external computing system, with the resulting computer executable instructions being provided to the additive manufacturing device. The instructions are suitable for execution of the processor and for storage on the computer readable storage medium. The non-transitory computer-readable medium may comprise any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory.

[0108] Given the above, the design and manufacture of implementations of the subject matter and the operations described in this specification can be realized using digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. For instance, hardware may include processors, microprocessors, electronic circuitry, electronic components, integrated circuits, etc. Implementations of the subject matter described in this specification can be realized using one or more computer programs, i.e., one or more modules of computer program instructions, encoded on computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium can also be, or be included in, one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices).

[0109] Although additive manufacturing technology is described herein as enabling fabrication of complex objects by building objects point-by-point, layer-by- layer, typically in a vertical direction, other methods of fabrication are possible and within the scope of the present subject matter. For example, although the discussion herein refers to the addition of material to form successive layers, one skilled in the art will appreciate that the methods and structures disclosed herein may be practiced with any additive manufacturing technique or other manufacturing technology.

[0110] Various systems or processes have been described to provide examples of embodiments of the claimed subject matter. No such example embodiment described limits any claim and any claim may cover processes or systems that differ from those described. The claims are not limited to systems or processes having all the features of any one system or process described above or to features common tomultiple or all the systems or processes described above. It is possible that a system or process described above is not an embodiment of any exclusive right granted by issuance of this patent application.

[0111] For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth to provide a thorough understanding of the subject matter described herein. However, it will be understood by those of ordinary skill in the art that the subject matter described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the subject matter described herein.

[0112] As used herein, an element or feature introduced in the singular and preceded by the word "a" or "an" should be understood as not necessarily excluding the plural of the elements or features. Further, references to "one example" or “one embodiment” are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the described elements or features. Reference herein to “example” means that one or more feature, structure, element, component, characteristic and / or operational step described in connection with the example is included in at least one embodiment and / or implementation of the subject matter according to the subject disclosure. Thus, the phrases “an example,” “another example” and similar language throughout the subject disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example.

[0113] Unless explicitly stated to the contrary, examples or embodiments "comprising" or "having" or “including” an element or feature or a plurality of elements or features having a particular property may include additional elements or features not having that property. Also, it will be appreciated that the terms “comprises”, “has”, “includes” means “including but not limited to” and the terms “comprising”, “having” and “including” have equivalent meanings.

[0114] As used herein, the term “and / or” can include any and all combinations of one or more of the associated listed elements or features.

[0115] The terms “coupled” or “coupling” as used herein can have several different meanings depending in the context in which these terms are used. For example, the terms coupled or coupling can have a mechanical, electrical or communicative connotation. For example, as used herein, the terms coupled or coupling can indicate that two elements or devices are directly connected to one another or connected to one another through one or more intermediate elements or devices via an electrical element, electrical signal, ora mechanical element depending on the particular context. Furthermore, the term “operatively coupled” may be used to indicate that an element or device can electrically, optically, or wirelessly send data to another element or device as well as receive data from another element or device.

[0116] Reference herein to “configured” denotes an actual state of configuration that fundamentally ties the element or feature to the physical characteristics of the element or feature preceding the phrase “configured to.”

[0117] Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of a lower- numbered item (for example, a “first” item) and / or a higher-numbered item (for example, a “third” item).

[0118] As used herein, the terms “approximately” and “about” represent an amount close to the stated amount that still performs the desired function or achieves the desired result. For example, the terms “approximately” and “about” may refer to an amount that is within engineering tolerances that would be readily appreciated by a person skilled in the art.

[0119] The embodiments described herein may be implemented as a combination of hardware or software in relation to additive manufacturing, as described above. Further, in some examples, one or more of the systems and methods described herein may be implemented in or as part of a distributed or cloud-based computing system having multiple computing components distributed across a computing network. The distributed or cloud-based computing system be a publicly accessible, distributed or cloud-based computing cluster, such as a computing clustermaintained by Microsoft Azure™, Amazon Web Services™, Google Cloud™, or another third-party provider.

[0120] Some aspects of the embodiments described herein may be implemented via software in relation to additive manufacturing that is written in a high- level procedural language such as object-oriented programming language. Accordingly, the program code may be written in any suitable programming language such as Java, Python or Rust, for example. Alternatively, or in addition thereto, some of these elements implemented via software may be written in assembly language, machine language or firmware as needed. In either case, the language may be a compiled or interpreted language.

[0121] At least some of these software programs may be stored on a storage media (for example, a computer readable medium such as, but not limited to, readonly memory, magnetic disk, optical disc) or a device that is readable by a general or special purpose programmable device. The software program code, when read by the programmable device, configures the programmable device to operate in a new, specific, and predefined manner to perform at least one of the methods described herein.

[0122] Furthermore, at least some of the programs associated with the systems and methods described herein may be capable of being distributed in a computer program product including a computer readable medium that bears computer usable instructions for one or more processors. The medium may be provided in various forms, including non-transitory forms such as, but not limited to, one or more diskettes, compact disks, tapes, chips, and magnetic and electronic storage.

[0123] What has been described is merely illustrative of the application of the principles of the disclosure. Other arrangements and methods can be implemented by those skilled in the art without departing from the scope of the disclosure.

Claims

What is claimed is:1 . An unmanned aerial vehicle (UAV) comprising: an airframe providing an enclosure that is made of an electrically conductive material and that is sized to enclose at least one motor drive component.

2. The UAV of claim 1 , wherein the airframe comprises a plurality of airframe parts that provide the enclosure and that are contiguous, each airframe part of the airframe parts being electrically conductive.

3. The UAV of claim 2, wherein the airframe parts are electrically bonded.

4. The UAV of claim 3, wherein the airframe parts are electrically bonded with a resistance of less than about 0.1 ohms.

5. The UAV of any one of claims 1 to 4, further comprising copper tape covering mating surfaces of the airframe parts.

6. The UAV of any one of claims 1 to 5, wherein the enclosure is integral with the airframe.

7. The UAV of claim 6, wherein the enclosure is integral with a main body, a motor enclosure, or an arm supporting the motor enclosure to the main body, or any combination thereof.

8. The UAV of any one of claims 1 to 7, further comprising the at least one motor drive component, the at least one motor drive component comprising an electric motor, a speed controller, an electrical power source, and their wire interconnects.

9. The UAV of any one of claims 1 to 7, wherein the enclosure being sized to enclose at least one motor drive component comprises the enclosure being sized to enclose a motor.

10. The UAV of claim 9, wherein the UAV further comprises a coupling that is configured to couple the motor and a propeller external to an area of the enclosure while maintaining an electromagnetic seal across the area.

11. The UAV of claim 10, wherein the area defines an aperture through which the coupling couples the motor and the propeller, and the coupling is electrically conductive and electrically connected to the area.

12. The UAV of claim 10 or 11 , wherein a portion of the coupling overlaps a portion of the enclosure.

13. The UAV of claim 10, wherein the area defines an aperture through which the coupling couples the motor and the propeller, and the coupling is electrically non- conductive.

14. The UAV of claim 13, wherein the coupling is made of plastic.

15. The UAV of any one of claims 1 to 14, further comprising an electromagneticbased sensor disposed external to the enclosure, wherein the electrically conductive material is sufficiently electrically conductive to mitigate electromagnetic radiation from within the enclosure to the electromagnetic-based sensor in a range of operation of the electromagnetic-based sensor.

16. The UAV of any one of claims 1 to 15, wherein the electrically conductive material is made of metal.

17. The UAV of claim 16, wherein the metal is solid aluminum.

18. The UAV of any one of claims 1 to 15, wherein the electrically conductive material is made of conductive polymer.

19. A computer readable medium storing instructions executable by one or more processors to control an additive manufacturing apparatus to manufacture the UAV of any one of claims 1 to 18.

20. A method of manufacturing a device via additive manufacturing, the method comprising: obtaining an electronic file representing a geometry of a product, wherein the product is a UAV according to any one of claims 1 to 18; andcontrolling an additive manufacturing apparatus to manufacture, over one or more additive manufacturing steps, the product according to the geometry represented in the electronic file.

Images