Method and apparatus for extending the operation of an unmanned aerial vehicle

A method of extending the operation of an unmanned aerial vehicle (UAV) is disclosed. The method comprises detecting that an energy storage device on board the UAV is depleted below a threshold level, landing the UAV at a base station, and initiating operation of the base station to cause a replacement mechanism thereof to remove the energy storage device on board the UAV from the UAV and to replace this with another energy storage device.

RELATED APPLICATIONS

This application claims the right of priority under 35 U.S.C. §119 to patent application no. EP12382181 filed May 17, 2012, in the European Patent Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

This invention relates to a method of extending the operation of an unmanned aerial vehicle (UAV). In other aspects, this invention relates to a UAV, a base station for a UAV and command-and-control device for a UAV.

UAVs are increasingly being used in civilian applications. Many “blue light” services such as the police services and fire-fighting services now use UAVs for intelligence-gathering operations, such as to provide real-time video images of locations that are difficult or dangerous to attend in person. UAVs are often able to provide such images quickly, conveniently and inexpensively. The UAVs used in such applications are relatively small compared to UAVs used, for example, in military strike operations. These smaller UAVs are often battery powered. This has the advantage of reducing complexity and cost. An example of such a UAV is the AR.Drone offered by Parrot.

A problem that exists with such smaller UAVs is that their operational duration is limited by their batteries. It is typical for such UAVs to be able to fly for no longer than 15 to 20 minutes before the battery becomes depleted. This is the principal limitation on the use of such devices.

Attempts have been made to improve the performance of batteries and so address this problem. For example, battery lives have been improved, charging times have been reduced and the energy consumption of UAVs has also been reduced. Despite these improvements this problem of limited endurance persists.

There therefore remains a need to address this problem.

SUMMARY

Embodiments of the present invention take a different approach from that taken previously. Rather than look at improving batteries, charging times or the power consumption of UAVs, the present approach is to provide an arrangement for the rapid replacement of batteries, or other energy storage devices, on UAVs such that effective operational duration can be extended.

According to a first aspect of this invention, there is provided a method of extending the operation of an unmanned aerial vehicle (UAV), the method comprising the steps of detecting that an energy storage device on board the UAV is depleted below a threshold level, landing the UAV at a base station, and initiating operation of a base station to cause a replacement mechanism thereof to remove the storage device on board the UAV from the UAV and to replace this with another storage device.

The method may further comprise the step of operating the base station to detect the position of the UAV relative to the base station when landed. This may include operating sensors at the base station to sense the position of the UAV. Sensing the position may include sensing the orientation of the UAV. Sensing the position may comprise operating pressure sensors positioned in and/or on a landing surface of the base station and/or optical sensors positioned in and/or on and/or around that surface. The surface may be a launch and recovery pad. Sensing the position may comprise generating information indicative of the position and/or orientation of the UAV.

The operation of the base station may comprise the replacement mechanism operating to take the other storage device from a store thereof. The operation of the base station may comprise operating the replacement mechanism using the detected position and/or orientation of the UAV to move replacement structure of the replacement mechanism to the UAV to remove the storage device therefrom. The operation of the base station may comprise operating the replacement mechanism using the information indicative of the sensed position and/or orientation of the UAV to move the replacement structure of the replacement mechanism to the UAV to couple the other storage device thereto. These steps may occur in the sequence in with they are recited herein; they may occur in another sequence.

The other storage device may not be depleted below the threshold. The store may be a charging station at which storage devices are replenished with energy such that their store thereof is above the threshold and such that the store of energy therein is substantially at a maximum. Each storage device may be a battery, a super capacitor, and/or a container of fuel.

The method may be carried out as a result of instructions executed by a processor on the UAV and/or a processor at the base station and/or a processor at a remote command-and-control device.

According to a second aspect of this invention, there is provided a UAV, the UAV arranged to carry out one, more or all of the steps of the method of the first aspect.

According to a third aspect of this invention, there is provided a command-and-control device arranged to carry out one, more or all of the steps of the method of the first aspect. The command-and-control device may comprise computer processing means. For example, it may comprise a computer such as a portable computer. Non exhaustive examples of a portable computer comprise a laptop, a tablet PC and a smartphone.

According to a fourth aspect of this invention, there is provided a base station arranged to carry out one, more of all of the steps of the method of the first aspect. The base station may be arranged as defined hereinabove.

The base station may comprise the replacement mechanism at the base station to remove the storage device on board the UAV from the UAV and replace this with another storage device. The base station may comprise the sensors to sense the position of the UAV. The replacement mechanism may comprise the replacement structure to remove the storage device from the UAV. The replacement mechanism may comprise a robot arm arranged to remove and/or fit storage device to and/or from the UAV. The base station may comprise the store of energy storage devices. The base station may comprise the landing surface.

Features of the first aspect may also be features of each other aspect.

Operation of the UAV may be controlled as a result of instructions executed by a processor on the UAV and/or a processor at the remote command-and-control device. Operation of the base station may be controlled by a processor at the base station and/or by a processor at the UAV and/or by a processor at the remote command-and-control device.

One, more or all steps may happen automatically subsequent to it being detected that the energy storage device on board the UAV is depleted below a threshold level

According to a fifth aspect of this invention, there is provided a record carrier comprising processor-executable instructions to cause a processor to carry out a method according to the first aspect.

The record carrier may comprise solid state storage means, such as, for example, a ROM, EPROM and/or EEPROM. The record carrier may comprise optical and/or magnetic storage means, such as, for example, a CD-ROM, DVD-ROM and/or magnetic storage disk. The record carrier may comprise a signal such as an electrical, optical and/or wireless signal.

DETAILED DESCRIPTION

FIG. 1shows in schematic form an overview of a UAV100, a base station200that includes a charging station300, and a command-and-control (C2) station400.

In this embodiment, the UAV100is an existing UAV, such as the AR.Drone provided by Parrot. It is a battery-powered quad-rotor UAV that is able to communicate wirelessly with the C2 station400. The wireless communication is such that the UAV can receive commands from the C2 station400that control operation of the UAV100, and can send information about operation of the UAV100to the C2 station400. The UAV100has an energy storage device in the form of a removable and rechargeable battery110.

The C2 station400is, in this embodiment, a laptop that communicates wirelessly with the UAV100using a radio. The C2 station400communicates using WiFi. In other embodiments, other forms of wireless communication are envisaged.

The base station200takes the form of a launch and recovery pad210on which the UAV100can land and from which it can take off. The pad210is arranged with sensors (not shown) to sense the position and orientation of the UAV100when the UAV100is on the pad210. In this embodiment, this is done by the provision of pressure sensors embedded within the pad210that are responsive to the weight of the UAV100to produce a signal indicative of the position of the UAV210on the pad. Optical sensors are also provided on and around the pad210to provide a signal indicative of the position and orientation of the UAV100when positioned on the pad210. Signals produced by the sensors are fed to a control unit (not shown) of the base station200. The control unit includes a microprocessor and a record of software executable by the microprocessor to cause it to operate the base station200in the manner described herein. The control unit is operable to ascertain, from the signals produced by the sensors, the position and orientation of the UAV100on the pad210.

Also forming part of the base station200is a robot arm220. The robot arm220is arranged to access the UAV100wherever the UAV100is positioned on the pad210. In this embodiment, this is accomplished by the robot arm220having wheels230that allow the robot arm, under the control of the control unit, to move over the pad210. Movement of the robot arm220is further provided for by it being articulated such that sections of the arm220are pivotable relative to other sections of the arm220. One such pivot is shown at222. A battery replacement section223of the arm220is provided with two battery engagement portions224. Each portion is provided with selectively operable magnetic contacts that are operable to releasably engage a battery when adjacent to a battery, such that the battery is grasped by the engagement portion224for lifting, moving and subsequently releasing. In other embodiments, other forms of engagement, such as a pincer arrangement, are envisaged. The battery-replacement section223is pivotally mounted adjacent its centre to the remainder of the robot arm220such that the relative positions of each of the two engagement portions224can be swapped by rotating the replacement section223180 degrees about its pivot. The purpose of this will become clear.

Again, operation of the robot arm220, including the battery-replacement section223and the engagement portions224is under the control of the control unit of the base station200.

The charging station300forms part of the base station200. The purpose of the charging station300is to hold batteries for charging and to receive depleted batteries from, and make recharged batteries available to, the robot arm20. Accordingly, the charging station300is arranged to hold multiple batteries (in this embodiment five are envisaged) and to charge each one from a depleted state to a state of maximum charge. The charging station is positioned within reach of the robot arm220such that the robot arm220can deposit for charging at the charging station300a depleted battery that has been removed from the UAV100and can collect from the charging station300a recharged battery for fitting to the UAV100. The charging station300also operates under the control of the control unit of the base station200.

The control unit of the base station200also has a wireless communication unit to communicate wirelessly, again in this embodiment by using WiFi, with the C2 station400.

The C2 station400takes the form of, in this embodiment, a laptop computer. The computer is able to communicate wirelessly, in the manner previously described, with each of the control unit of the base station200and the UAV100. The C2 station400runs software that controls operation of both the UAV100and the base station200. In other embodiments, however, it is envisaged that the base station200may control its own operation in response to the software running thereon and in response to signals from the UAV100and/or detecting that the UAV100has landed on the pad210.

Operation of the various components will now be described with reference to the flowchart ofFIG. 2.

FIG. 2shows the method of operation500of the C2 station400. This method500is a subroutine that is executed during normal operation of the UAV10under the control of the C2 station400when the C2 station detects at a first step510that the battery110of the UAV is discharged below a threshold value such that it is determined that the battery110should be replaced.

Upon determining at step510that the battery110should be replaced, the method500proceeds to step520at which the C2 station400sends a signal to the base station200that the robot arm220should retrieve a fully charged battery120from the charging station300. The method500being run by the C2 station then proceeds to step530at which the C2 station400controls the UAV100to land on the launch and recovery pad210of the base station200.

The method500being run by the C2 station400then waits at step540for a signal from the base station200that the UAV100has been fitted with the new battery120and is ready for takeoff.

In the meantime, the method600runs on the base station200. This is in the form of software being executed by the control unit of the base station200and is shown inFIG. 3. The method600is initiated at a first step610when the base station200receives the signal from the C2 station400that the robot arm220should retrieve the fully charged battery110from the charging station300.

Upon receiving this signal, the method600running on the base station200proceeds to step620at which the control unit of the base station200controls the robot arm to move to the charging station300. When the robot arm is at the charging station300, the magnetic contacts of the engagement portion224that is currently positioned at the end of the robot arm220are operated to pick up the fully charged battery120. The robot arm220is then operated to rotate the battery replacement section223180 degrees about its pivot such that the other, empty, engagement portion224is at the end of the arm220.

The method of the base station600then moves on to step630at which the base station detects whether or not the UAV100has landed on the pad210. This is done by sensing the signals from the pressure sensors in the pad210and the optical sensors in and around the pad210. When it is detected that the UAV100has landed on the pad, the signals from the sensors are used at step640to determine the position and orientation of the UAV100on the pad210.

Once this is done, the robot arm220is operated at step650to move to the determined position of the UAV100and to operate the currently empty engagement portion224that is at the end of the arm220to energise the magnetic contacts and pick up the discharged battery110from the UAV. The battery replacement section223of the robot arm220is then rotated 180 degrees about its pivot to swap the positions of the discharged battery110and the fully charged battery120. In this way, the fully charged battery120is now positioned adjacent the UAV100. The fully charged battery120is then dropped into placed in the UAV100by de-energising the magnetic contacts of the relevant battery engagement portion224.

The method then proceeds to step660at which the robot arm is moved into a position in which it projects outside and away from the pad210so as not to obstruct take off of the UAV100. Once this is done, the base station200sends a signal at step670to the C2 station400that the batteries110,120have been swapped and the UAV100is ready to resume operation.

The method600running on the base station200then waits at step680until it is detected, by way of the sensors, that the UAV has left the pad210. Once it has been determined that the UAV has left the pad210the robot arm220is operated to drop off the discharged battery110at the charging station300for recharging. The method600then returns to step610to wait for another signal that it should pick up another fully charged battery.

Returning now to the method500running on the C2 station, that method had been waiting at step540for a signal that the UAV's discharged battery110had been swapped for a fully charged battery120and is ready to resume operation. As mentioned, this signal is sent from the base station200at step670of the method running on the base station200. Upon receiving this signal, the C2 station400proceeds to step550at which it controls the UAV100to take off for resumed operation. The subroutine then returns to the first step510to wait for the new battery120to become discharged and run the method again.

In this way, a discharged battery on the UAV is quickly, conveniently and repeatedly swapped for a fully charged battery, thereby prolonging the effective operating duration of the UAV100to be many times its normal operating duration.

In the foregoing discussion, specific implementations of exemplary processes have been described, however, it should be understood that in alternate implementation, certain acts need not be performed in the order described above. In alternate examples, some acts may be modified, performed in a different order, or may be omitted entirely, depending on the circumstances. Moreover, in various alternate implementations, the acts described may be implemented by a computer, controller, processor, programmable device, firmware, or any other suitable device, and may be based on instructions stored on one or more computer-readable media or otherwise stored or programmed into such devices (e.g. including transmitting computer-readable instructions in real time to such devices). In the context of software, the acts described above may represent computer instructions that, when executed by one or more processors, perform the recited operations. In the event that computer-readable media are used, the computer-readable media can be any available media that can be accessed by a device to implement the instructions stored thereon.