GB2587325A

GB2587325A - A drone

Info

Publication number: GB2587325A
Application number: GB1912846.1A
Authority: GB
Inventors: William Gibson James; Brazinskas Mantas
Original assignee: Tethered Drone Systems Ltd
Current assignee: Tethered Drone Systems Ltd
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2021-03-31
Anticipated expiration: 2039-09-06
Also published as: GB201912846D0; WO2021044388A1; GB2587325B

Abstract

A drone comprising a plurality of hollow struts (Fig. 1, 16a – 16f), which extend from the body of the drone, each comprising a motor (Fig. 2, 18a – 18f) for driving a propeller (Fig. 2, 17a – 17f) and a fan. The fan draws air down the hollow struts in order to cool the components within the body. The fan may be located at the end of the strut nearest the drone body, such that the fan draws air from an inlet and exhausts it through the end of the strut further from the drone body. Inlet includes a cowl to prevent the ingress of rainwater. A drone body comprising electrical circuitry and a fan in order to cool the components, driving exhaust air from a vent port. The components of the drone may have a heat sink, possibly including a fin, and the fans may be positioned so as to force air over the heat sink. The drone may include: image capture and image transmitter for a remote receiver; air quality monitor and signal transmitter; a tether for the drone, which comprises a winch, and may be used to receive an electrical current.

Description

An Improved Drone The present invention relates to improvements to drones and to an improved drone deployment system.

A drone is another name for an unmanned aerial vehicle (UAV). A drone or UAV is an aircraft without a human pilot on board and is therefore a specific type of unmanned vehicle.

UAVs are also referred to as unmanned aircraft systems (UAS) which may include a UAV, a ground-based controller and a system of communications between the two.

Drones (UAVs) may operate with various degrees of autonomy: either under remote control by a human operator or autonomously by onboard computers and control systems.

Drones have a number of uses in defence and security applications.

There is a trade-off between payload and flight time, and this is especially the case where a drone is powered by batteries or rechargeable cells.

There is a particular type of drone, which is referred to as a tethered drone, which is a drone that is tethered and receives an electric current to power on board motors that operate propellers and is retained in a limited and relatively restricted airspace which is defined by the maximum length of the tether.

Recently, following the advent of tethered drones, the problem of maximum flight time is overcome. However, tethered drones by their nature have a limited range but they have an ability to stay aloft for extended periods.

Despite their theoretically limitless flight time there is a need to transmit electric current at a high voltage otherwise tethered drones become less efficient due to resistive losses, which are proportional to the square of the electric current (12). Consequently tethered drones have required on-board transformers in order to 'step down' voltage and increase the level of supply current to on-board components and the motors that drive the propellers.

Because tethered drones can be kept aloft for prolonged periods, which are significant longer in duration than untethered or 'free flying drones, there is a greater need to protect internal components from the elements, in particular rain and ice as prolonged exposure to water is likely to lead to problems in the on-board transformers and other electronic components which operate and control the drone. There is therefore a greater need to protect these electronic components from exposure to rain due to the fact that they are more likely to encounter rain during a prolonged flight especially in marine or wet climates. This was achieved by surrounding the components with a lightweight cover in order to protect them.

Even where transformers are efficient, they are prone to overheating which leads to losses, inefficiency and the risk of drones spontaneously igniting. The fact that the electronic components and especially the transformers are now enclosed in a closed cover, has exacerbated the problem of overheating.

An aim of the invention is to reduce the risk of overheating of drones, in particular tethered drones.

Another objective of the invention is to optimise the amount of power to payload.

A further object of the invention is to optimise passive cooling of drones, in particular tethered drones.

According to a first aspect of the invention there is provided a drone including at least one fan which cools components within the drone body.

An advantage of the invention is that it optimises the amount of payload which is encountered in free flying drones.

Where drones are tethered greater payloads are able to be carried, because components can be driven to higher operating regimes, without the need to refuel or recharge and because additional energy can be used to drive a fan so as to cool components. Consequently where previously components risked over-heating, as a result of the invention components are force cooled thereby improving efficiency and ensuring continuous operation.

According to a second aspect of the invention there is provided a drone including: a plurality of hollow struts which extend from a drone body; and a motor is associated with each strut, the motor drives a propeller, characterised in that centrifugal fan elements are driven by the motor, the centrifugal fan elements when actuated cause air to be entrained through an associated hollow strut in order to cool components within the drone body.

Ideally the components are in thermal contact with a heat sink over which the forced air passes. Ideally the heat sink includes fins, slots or apertures which increase the surface area available for cooling.

Centrifugal fan elements draw air via at least one inlet, which is ideally located at an end of the strut closest to the drone body, so that air exhausts from an end of a strut furthest from the drone body. However, the one or more inlets may be located at different locations in the strut and optionally include vanes for directing air at an inlet or an outlet.

Preferably the inlet includes a cowl that is shaped and dimensioned to reduce ingress of rainwater which might enter the strut and inadvertently increase the weight of the drone According to a third aspect of the invention there is provided a drone which has a drone body enclosing a board on which electrical and electronic components are mounted, characterised in that at least one fan is provided within the body and the least one fan is operative to force air across the electrical and electronic components and to exhaust air from the body via at least one port defined in a wall of the drone body.

Preferably the at least one fan is mounted on the board.

Ideally the least one port that is defined in the base of the drone body is formed in the base so that when cooling air exhausts, the exhaust air does not interfere with the airflow, from the propellers, so as not to interfere or reduce downward airflow from the propellers that create lift forces.

In some embodiments the drone has mounted on the board at least one power regulator for modifying the electric current from a low current to a higher current for supply to the motors. Associated with the at least one power regulator is a fan. Optionally the fan may be used to cool two or more regulators.

Preferably the drone includes at least one power regulator which is a transformer. The at least one power regulator has a heat sink and the at least one fan is dimensioned and oriented to force air over the heatsink.

In some embodiments the drone has at least one port that is located in a base of the drone body. By forcing exhaust air sideways, through the base of the drone body, there is an improvement in cooling as coolant air is forced to regions of air around the body of the drone which is then entrained into the propeller wash.

Ideally components are connected to, and are in thermal contact with, a heat sink over which air is forced. The heat sink preferably includes fins.

Some drones include a tether which tethers the drones to a ground based anchor; the tether also supplies an electric current to components and motors in the drone.

In some embodiments the drone includes an imager and a transmitter for transmitting an image to a remote receiver.

Optionally the drone includes or has an air quality monitor mounted thereon.

Some embodiments include a transmitter for transmitting a signal indicative of air quality to a remote receiver. The transmitter may be connected to a remote receiver via a hardwire link in the tether or optionally via a radio frequency (RF) communication channel or even via an optical communication system.

Ideally the drone receives an electric current via a wire which forms the tether and the current powers the components and the at least one fan and the motors According to another aspect of the invention there is provided a tethered drone system that includes: a winch which powers a drum around which the tether is wound; and the drum has apertures formed therein, air passes through the apertures in order to cool the tether and a cable that transmits electric current to the drone.

The system overcomes resistive heating which occurs as result of resistive losses that occur in the cable or wire which supplies the electric current.

Embodiments of the invention will now be described, by way of example only and with reference to the Figures, in which: Figure 1 shows an overall view of one example of a drone; Figure 2 shows a plan view of the drone in Figure1; Figure 3A is a part sectional, side elevation view of one of the struts and shows a motor and a propeller; Figure 3B is a part sectional, plan view corresponding to 3A and shows the strut and the motor and a portion of a propeller; Figure 4 is a part sectional view of an alternative arrangement to the embodiment shown in Figures 3A and 3B; Figure 5 is an overall view of the arrangement shown in Figures 3A and 3B and indicates the position of a centrifugal fan and its blades; Figure 6 is a partial, sectional plan view of an interior of the drone shown in Figure 1 and depicts heat sinks; Figure 7 is a part sectional plan view of an interior of the drone shown in Figure 6 and depicts heat sinks and location of fans; and Figure 8 shows a diagrammatic view of a deployment system including the drone shown in Figures 1 to 7 and a drum around which a tether is wound.

Referring to the Figures generally, there is shown a drone 10 comprising a drone body 12 which is covered by a drone housing or cover 14. Extending from the drone body 12 are six struts 16a to 16f respectively.

Referring now to Figures 2 and 3 there are shown views depicting propellers 17a to 17f mounted on motors 18a to 18f respectively. The struts 16a to 16f support motors 18a to 18f respectively. Each motor 18 has a centrifugal fan 28a to 28f, with fan blades which are shown in greater detail in Figure 5. Centrifugal fans 28 are mounted on and driven by each motor 18a to 18f at the end of each strut. However, in some embodiments centrifugal fans 28 may be provided on only some of the motors 18a to 18f but in a manner so as to ensure stability in flight and balanced air flow.

Referring again to Figure 3 and Figure 4 the centrifugal fan 28c is driven directly from motor 18c via a motor drive 29c. Propellers 17c are connected to the motor 18c and an interconnect joins their ends one to another. Mounted towards distal ends of each strut 16 are motors 18a to 18f respectively.

Figure 4 shows a detailed view of a support strut 16c and shows an alternative arrangement of locating the motor 16c to the arrangement depicted in Figure 3. The centrifugal fan 28c is shown below the motor 18c and is driven directly from a motor drive (shown in detail in Figure 5). Figure 5 is an enlarged view, corresponding to the view, shown in Figure 3 and Figure 4 and shows the strut 16c supporting the centrifugal fan 28c below the motor 18c. The struts 16 are generally square in cross section and are hollow in order to reduce weight. The struts 16 connect to the housing 14 and define a pathway for the air which cools the components. The struts 16 supported the motors 18 and centrifugal fans 28. The position of the centrifugal fan 28 and its blades is depicted.

Figure 6 is a part sectional plan view of an interior of the drone shown in Figure 1 and depicts heatsinks 24. The heatsink 24 extends from an inner region of the housing 14, on which components are mounted and extends through the drone housing or cover 14 projecting to an exterior of the drone 10. The heatsink 24 encircles the housing or cover 14, in the form of a hoop or flat disc, with apertures or slots cut therefrom in order to optimise airflow and so as to enhance forced convective cooling as the drone flies through the air. Fans 44, located inside the housing or cover 14, force air over the components, in particular the regulators 40, in order to force cool them. It is appreciated that the regulators 40 may also have integral fins formed thereon in order to further increase available surface area for forced and radiative cooling.

Figure 7 is a part sectional plan view of an interior of the drone shown in Figure 6 and depicts heat sinks and location of fans. Components 19 are supported on a chassis 20 within the housing 14. Air is drawn through the chassis openings 44a in the direction of arrow A, through the interior of the housing and across components 19 which are thereby cooled. Air is subsequently passed via a slots or apertures (not shown) formed in the lateral wall of the drone housing or cover 14.

Figure 8 shows a diagrammatic view of a deployment system including the drone 10 shown in Figures 1 to 7 and a drum 60 around which tether 50 is wound. The drum is transported on a vehicle 70 and an imaging system 80 is supported on the drone 10. Electric current is supplied to the drone 10 via the tether 50.

In one embodiment the drum 60, around which the tether 50 is wound has apertures (not shown) formed therein, through which apertures air passes in order to cool the tether 50 The invention has been described by way of exemplary embodiments and variation may be made to them, without departing from the scope of protection, as defined in the appended claims.

Pads List Drone 10 Drone body 12 Drone housing or cover 14 Struts 16a to 16f Propellers 17a to 17f Motors 18a to 18f Components 19 Chassis 20 Interconnect 21 Openings 22 Heatsink 24 Blocking fairing 25 Centrifugal fans 28 Motor Drive 29 Inlet 30 Dust filter 32 Apertures 36 Regulators 40 Fans 44 Tether 50 Drum 60 Vehicle 70 Imager 80

Claims

Claims 1 A drone includes: a plurality of hollow struts which extend from a drone body; and a motor is associated with each strut for driving a propeller, characterised in that fan elements are driven by the motor, the fan elements when actuated cause air to be entrained through an associated hollow strut in order to cool components within the drone body.
2. A drone according to claim 1 wherein the components are in thermal contact with a heat sink over which air passes.
3. A drone according to claim 2 wherein the heat sink includes fins.
4 A drone according to any preceding claim wherein the fan elements draw air via an inlet, located at an end of the strut closest to the drone body, so that air exhausts from an end of a strut furthest from the drone body.
5. A drone according to claim 4 wherein the inlet includes a cowl that is shaped and dimensioned to reduce ingress of rainwater.
6 A drone has a drone body which encloses a board on which electrical and electronic components are mounted, characterised in that at least one fan is provided within the body and the least one fan is operative to force air across the components and to exhaust air from the body via at least one port defined in a wall of the drone body.
7 A drone according to claim 6 wherein at least one power regulator modifies the electric current supplied to a motor, the at least one power regulator is mounted on the board and associated with the at least one power regulator is a fan.
8. A drone according to claim 7 wherein the at least one power regulator has a heat sink and the at least one fan forces air over an associated heatsink.
9. A drone according to any of claims 6 to 8 wherein the at least one pod is located in the base of the drone body.
10.A drone according to any of claims 6 to 9 wherein components are connected to, and are in thermal contact with, a heat sink over which air is forced.
11 A drone according to claim 10 wherein the heat sink is in the form of a circular disc which extends form an interior of the drone housing and surrounds the housing.
12.A drone according to claim 11 wherein the heat sink includes fins.
13.A drone according to any of claims 7 to 12 wherein the at least one power regulator is a transformer.
14.A drone according to any preceding claim includes an imager and a transmitter for transmitting an image to a remote receiver.
15.A drone according to any preceding claim includes an air quality monitor and a transmitter for transmitting a signal indicative of air quality to a remote receiver.
16.A drone according to any preceding claim wherein the drone is attached to a tether.
17.A drone according to claim 16 receives an electric current is delivered to the drone via a wire which forms the tether and the current powers the components and the at least one fan and the motors.
18.A drone deployment system includes the drone according to either claim 16 or 17 comprises a winch which powers a drum around which the tether is wound; and the drum has apertures formed therein, through which apertures air passes in order to cool the tether.