Technical Field

[0001] The present disclosure relates to a method and system for herding animals. The present disclosure also relates to an unmanned vehicle, such as an unmanned aerial vehicle. In particular, the method and system utilises one or more unmanned vehicles to gather animals, such as sheep, in a predetermined area and direct the animals to a predetermined location.

Background

[0002] Animal herding is a vital step of livestock farming. Herding has long been performed by trained animals, such as herding dogs, to control the movement of livestock, such as cattle, sheep and goats, under the direction of a person. Typically, herding dogs will nip at the heels of animals and bark, which will elicit a flight response by the animals causing them to move. The main drawbacks of herding dogs are their limited life span and working capacities.

Moreover, herding dogs require significant training and upkeep, which can be a significant time and cost investment for livestock farmers.

[0003] Some studies have been conducted on the application of robots in herding animals. In particularly, ground-based robots were employed to drive animals through physical collisions or stimuli, such as bright colours, to influence the animal’s behaviour. However, such methods cause significant stress and harm to the animals during herding. A further disadvantage of such ground-based robots is the lack of agility and manoeuvrability across vast and uneven terrain, which can result in undesired results during herding.

Object

[0004] It is an object of the present disclosure to substantially overcome or ameliorate one or more of the above disadvantages, or at least provide a useful alternative.

Summary

[0005] In accordance with an aspect of the present disclosure, there is provided a method for herding animals, the method comprising: capturing image data related to a plurality of animals in a predetermined area; determining a convex hull around the animals based on the image data; navigating one or more unmanned vehicles based on the convex hull; and during navigation, transmitting signals from the one or more unmanned vehicles towards the convex hull so that the animals are urged to aggregate together.

[0006] The method may further comprise: determining an extended hull based on the convex hull, wherein the extended hull may enclose the convex hull and define a path on which the one or more unmanned vehicles navigate.

[0007] The step of navigating one or more unmanned vehicles based on the convex hull may comprise: determining a steering point on the extended hull that is furthest from the centroid of the convex hull; and navigating the one or more unmanned vehicles along the extended hull to the steering point.

[0008] After the animals aggregate together, the method may further comprise: determining a minimum circular boundary around the animals based on the image data; navigating the one or more unmanned vehicles based on the circular boundary; and during navigation, transmitting signals from the one or more unmanned vehicles towards the circular boundary so that the animals are urged to move to a predetermined location.

[0009] The method may further comprise: determining an extended circular boundary based on the minimum circular boundary, the extended circular boundary surrounding the minimum circular boundary; and determining a driving path on the extended circular boundary based on the predetermined location.

[0010] The step of navigating the one or more unmanned vehicles based on the minimum circular boundary may comprise: navigating the one or more unmanned vehicles to oscillate between two points on the driving path.

[0011] In accordance with another aspect of the present disclosure, there is provided a system for herding animals, the system comprising: one or more first unmanned vehicles, each of the first unmanned vehicles configured to capture image data related to a plurality of animals in a predetermined area, and determine a convex hull around the animals based on the image data; and one or more second unmanned vehicles, each of the second unmanned vehicles configured to navigate based on the convex hull, and, during navigation, transmit signals towards the convex hull so that the animals are urged to aggregate together.

[0012] Each of the first unmanned vehicles may be further configured to determine an extended hull based on the convex hull, and wherein the extended hull may enclose the convex hull and define a path on which the one or more second unmanned vehicles navigate.

[0013] Each of the second unmanned vehicles may be further configured to determine a plurality of steering points on the extended hull that are furthest from the centroid of the convex hull, and navigate along the extended hull to one of the steering points.

[0014] After the animals are aggregated together, each of the first unmanned vehicles may be further configured to determine a minimum circular boundary around the animals based on the image data, and wherein each of the second unmanned vehicles may be further configured to navigate based on the minimum circular boundary, and, during navigation, transmit signals towards the minimum circular boundary so that the animals are urged to move to a predetermined location.

[0015] Each of the second unmanned vehicles may be further configured to: determine an extended circular boundary based on the minimum circular boundary, the extended circular boundary may surround the minimum circular boundary; determine a plurality of driving paths on the extended circular boundary based on the predetermined location; and navigate to a respective driving path to oscillate between two points on the driving path.

[0016] In accordance with a further aspect of the present disclosure, there is provided an unmanned vehicle, comprising: a body; an image capture device mounted to the body and configured to capture image data; a signal transmitter mounted to the body and configured to transmit signals; and a controller configured to: operate the image capture device to capture image data of a plurality of animals in a predetermined area; determine a convex hull around the animals based on the image data; navigate the unmanned vehicle based on the convex hull; during navigation, operate the signal transmitter to transmit signals towards the convex hull so that the animals are urged to aggregate together.

[0017] The controller may be further configured to determine an extended hull based on the convex hull, and wherein the extended hull may enclose the convex hull and define a path on which the unmanned vehicle navigates.

[0018] The controller may be configured to navigate the unmanned vehicle based on the convex hull by: determining a steering point on the extended hull that is furthest from the centroid of the convex hull; and navigating the unmanned vehicle along the extended hull to the steering point.

[0019] After the animals are aggregated together, the controller may be further configured to: determine a minimum circular boundary around the animals based on the image data; navigate the unmanned vehicle based on the minimum circular boundary; and during navigation, operate the signal transmitter to transmit signals towards the minimum circular boundary so that the animals are urged to move to a predetermined location. [0020] The controller may be further configured to: determine an extended circular boundary based on the minimum circular boundary, the extended circular boundary surrounding the minimum circular boundary; and determine a driving path on the extended circular boundary based on the predetermined location.

[0021] The controller may be configured to navigate the unmanned vehicle based on the minimum circular boundary by: navigating the unmanned vehicle to oscillate between two points on the driving path.

[0022] In accordance with yet another aspect of the present disclosure, there is provided unmanned vehicle, comprising: a body; a signal transmitter mounted to the body and configured to transmit signals; a communication system configured to communicate with one or more other unmanned vehicles; and a controller configured to: receive, via the communication system, data related to a convex hull around a plurality of animals; navigate the unmanned vehicle based on the convex hull; and during navigation, operate the signal transmitter to transmit signals towards the convex hull so that the animals are urged to aggregate together.

[0023] The controller may be further configured to receive, via the communication system, data related an extended hull, the extended hull may enclose the convex hull and define a path on which the unmanned vehicle navigates.

[0024] The controller may be configured to navigate the unmanned vehicle based on the convex hull by: determining a steering point on the extended hull that is furthest from the centroid of the convex hull; and navigating the unmanned vehicle along the extended hull to the steering point. [0025] After the animals are aggregated together, the controller may be further configured to: receive, via the communication system, data related to a minimum circular boundary around the animals; navigate the unmanned vehicle based on the minimum circular boundary; and during navigation, operate the signal transmitter to transmit signals towards the minimum circular boundary so that the animals are urged to move to a predetermined location.

[0026] The controller may be further configured to: receive, via the communication system, data related to an extended circular boundary which surrounds the minimum circular boundary; and determine a driving path on the extended circular boundary based on the predetermined location.

[0027] The controller may be configured to navigate the unmanned vehicle based on the minimum circular boundary by: navigating the unmanned vehicle to oscillate between two points on the driving path.

[0028] In the above aspects and embodiments, the signals transmitted may be directed towards the centroid of the convex hull.

[0029] In the above aspects and embodiments, the signals transmitted after the animals aggregate together may be directed towards the centre of the minimum circular boundary.

[0030] In the above aspects and embodiments, the signals transmitted from the one or more unmanned vehicles may be audio recordings.

[0031] In accordance with an embodiment of the present disclosure, there is provided an unmanned vehicle, comprising: a body; an image capture device mounted to the body and configured to capture image data; a communication system configured to communicate with one or more other unmanned vehicles; and a controller configured to: operate the image capture device to capture image data of a plurality of animals in a predetermined area; determine a convex hull around the animals based on the image data; and operate the communication system to send data related to the convex hull to one or more other unmanned vehicles.

Brief Description of Drawings

[0032] Embodiments of the present disclosure will now be described hereinafter, by way of examples only, with reference to the accompanying drawings, in which:

[0033] Fig. 1 is an illustration of an embodiment of a system, herding a plurality of animals;

[0034] Fig. 2 is a schematic illustration of observer and mustering unmanned aerial vehicles of the system of Fig. 1;

[0035] Fig. 3 is a flow diagram showing an embodiment of a method for herding animals;

[0036] Fig. 4 is a top view of a convex hull of a plurality of animals;

[0037] Fig. 5 is a top view of an extended hull of the convex hull of Fig. 4;

[0038] Fig. 6 is an enlarged view of AA of Fig. 5;

[0039] Fig. 7 is a top view of the mustering unmanned aerial vehicle moving to a deployed position on the extended hull, and the possible trajectories of the mustering unmanned aerial vehicle along the extended hull to move from the deployed position to a steering point;

[0040] Fig. 8 is an enlarged view of BB of Fig. 7;

[0041] Fig. 9(a) and 9(b) are top views of the mustering unmanned aerial vehicle of Fig. 7, at the time of transmitting signals towards the convex hull during navigation, and with the mustering unmanned aerial vehicle being at varying distances from the convex hull. [0042] Fig. 10 is a flow diagram showing a method of driving the herded animals;

[0043] Fig. 11 is a top view of a minimum circular boundary of a plurality of aggregated animals;

[0044] Fig. 12 is a top view of an extended circular boundary of the circular boundary of Fig. 11;

[0045] Fig. 13 is a top view of the extended circular boundary of Fig. 12, showing a driving path and a predetermined location;

[0046] Fig. 14 is another top view of Fig. 13, with the mustering unmanned aerial vehicle of Fig. 7 being navigated along the driving path; and

[0047] Fig. 15 is another top view of Fig. 13, showing a plurality of driving path segments.

Description of Embodiments

[0048] Figs. 1 and 2 show an embodiment of a system 10 for herding animals. The animals may be farmed animals including, sheep, cattle, goats, or other livestock that would ordinarily be aggregated as a herd. The system 10 comprises an ‘observer’ unmanned vehicle that is configured to monitor a plurality of animals 20 in a predetermined area, such as a pasture, and a ‘mustering’ unmanned vehicle in wireless communication with the observer unmanned vehicle and which is configured to gather the animals and drive the animals to a predetermined location. In the embodiment shown in Fig. 1, the observer unmanned vehicle is an observer unmanned aerial vehicle (UAV) 100 and the mustering unmanned vehicle is a mustering UAV 200.

[0049] The observer UAV 100 comprises a fuselage 102 and a controller 104 housed in the fuselage 102. The controller 104 is configured to control various functions of the observer UAV 100 and may be in the form of a microcontroller, for example, having a processor and a memory. The memory may be configured to store information and/or instructions for directing the processor, and the processor may be configured to execute instructions, such as those stored in the memory. The observer UAV 100 also comprises a power supply 106, for example, a rechargeable battery, for providing power to components of the observer UAV 100.

[0050] An image capture device 108 is mounted to the fuselage 102 and is operatively connected to the controller 104. The image capture device 108 is configured to capture aerial image data. The image capture device 108 may comprise, for example, one or more cameras and/or video cameras. Further, the observer UAV 100 comprises a communication system 110 housed in the fuselage 102 and which is operatively connected to the controller 104. The communication system 110 allows for wireless communication with the mustering UAV 200 through any wireless technology such as, for example, Wi-Fi, Bluetooth, or cellular network (e.g. 4G, 5G, etc.).

[0051] Moreover, the observer UAV 100 has a propulsion system 112 operatively connected to the controller 104. In this embodiment, the propulsion system 112 includes four propellers 114 connected to the fuselage 102. Each propeller 114 is configured to be controlled by the controller 104 to navigate the observer UAV 100 over the predetermined area.

[0052] The mustering UAV 200 will now be described. The mustering UAV 200 comprises a fuselage 202 and a controller 204 housed in the fuselage 202. The controller 204 is configured to control various functions of the mustering UAV 200 and may be in the form of a microcontroller, for example, having a processor and a memory. The memory may be configured to store information and/or instructions for directing the processor, and the processor may be configured to execute instructions, such as those stored in the memory. The mustering UAV 200 also comprises a power supply 206, for example, a rechargeable battery, for providing power to components of the mustering UAV 200.

[0053] Further, the mustering UAV 200 comprises a communication system 208 housed in the fuselage 202 and which is operatively connected to the controller 204. The communication system 208 of the mustering UAV 200 allows for wireless communication with the observer UAV 100 for data transmission therebetween. For example, the communication system 208 of the mustering UAV 200 may be configured to communicate with the communication system 110 of the observer UAV 100 through any corresponding wireless technology (e.g., Wi-Fi, Bluetooth, or cellular network). [0054] A signal transmitter 210 is mounted to the fuselage 202 and is operatively connected to the controller 204. The signal transmitter 210 is configured to transmit signals over a predetermined distance, e.g., 500 metres. In this embodiment, the signal transmitter 210 includes a speaker 212 configured to transmit a stored audio recording of a bark of a dog. It will be appreciated that the animals to be herded (e.g., a sheep), upon encountering the transmitted audio recording, will turn away and exhibit a flight response by beginning to move. The speaker 212 is also mounted to a stabiliser 214, such as a motion-controlled gimbal or a pan-tilt system, attached to the mustering UAV 200.

[0055] The mustering UAV 200 also comprises an onboard GPS receiver 216 operatively connected to the controller 202 and which is configured to obtain position data of the mustering UAV 200. Further, the mustering UAV 200 has a propulsion system 218 operatively connected to the controller 202. In this embodiment, the propulsion system 218 includes six propellers 220 connected to the fuselage 202. Each propeller 220 is configured to be controlled by the controller 202 to navigate the mustering UAV 200 over the predetermined area.

[0056] The controllers 104, 204, of the observer UAV 100 and the mustering UAV 200 are configured to execute instructions to carry out the method operations described hereinbelow. The system generally employs a two-part strategy of ‘gathering’ and ‘driving’.

Gathering Strategy

[0057] With reference to Fig. 3, the method begins at step 1000, in which the observer UAV 100 monitors a plurality of animals in a predetermined area. In this regard, the controller 104 of the observer UAV 100 navigates the observer UAV 100 over the predetermined area and operates the image capture device 108 to periodically capture image data of the plurality of animals in the predetermined area.

[0058] At step 1100, the controller 104 of the observer UAV 100 determines a convex hull 300 in two-dimensional space around the plurality of animals 20 based on the captured image data. In this embodiment as shown in Fig. 4, the convex hull 300 is a polygon with vertices P _t and straight-line edges 302 that extend between the vertices Pi. The vertices P _t correspond to the positions of the animals on the boundary of the plurality of animals 20 based on the captured image data. The set of vertices of the convex hull 300 may be described as: where: n _p is the number of vertices of the convex hull 300.

[0059] The controller 104 of the observer UAV 100 also determines the centroid C _o of the convex hull 300 through known methods.

[0060] Subsequently, at step 1200 of Fig. 3, the controller 104 of the observer UAV 100 determines an extended hull 400 in two-dimensional space based on the convex hull 300. The extended hull 400 defines a path on which the mustering UAV 200 navigates to aggregate the plurality of animals 20. In this embodiment, as shown in Fig. 5, the extended hull 400 is a polygon that encloses the convex hull 300 at a predetermined distance d _s therefrom. In this embodiment, the predetermined distance d _s is about 15 metres. The extended hull 400 has straight-line edges 402 that are parallel to respective straight-line edges 302 of the convex hull 300, and vertices E _t that are each defined by the intersection of two adjacent straight-line edges 402. Each of the vertices E _t of the extended hull 400 are associated with a respective vertex P _t of the convex hull 300. The set of vertices S of the extended hull 400 may be described as:

(2) S = {F , i = 1, ..., n _e where: n _e is the number of vertices E _t of the extended hull 400; and n _e = n _p .

[0061] Fig. 6 shows an example of how the extended hull 400 may be constructed based on the convex hull 300. Vertex P^ and vertex P _i+1 of the convex hull 300 represent adjacent vertices of the vertex P _t of the convex hull 300. The straight-line edges l ₁₇ l ₂ of the extended hull 400 are constructed so as to be parallel to the straight-line edges PiP _i+1 , PtPt- of the convex hull 300, respectively, and spaced at the predetermined distance d _s therefrom. The intersection of straight-line edges Z ₁₅ l ₂ defines the vertex E _L of the extended hull 400. The position represents the intersection of straight-line edge l of the extended hull 400 and the extension of the straight-line edge PiPt- of the convex hull 300, and the position L ₂ represents the intersection of straight-line edge l ₂ of the extended hull 400 and the extension of the straight-line edge PiPt ₊ of the convex hull, thus defining the parallelogram P _i L ₁ E _i L ₂ .

[0062] In response to determining the convex hull 300 and the extended hull 400, the controller 104 of the observer UAV 100 transmits, via the communication system 110, data related to the convex hull 300 and the extended hull 400 to the mustering UAV 200. In other embodiments, the controller 104 of the observer UAV 100 may transmit to the mustering UAV 200 data related to the extended hull 400 only.

[0063] The controller 204 of the mustering UAV 200 receives, via the communication system 208, data from the observer UAV 100 related to the convex hull 300 and the extended hull 400. The controller 204 of the mustering UAV 200 also periodically obtains real-time position data of the mustering UAV 200 via the GPS receiver 216. In response to receiving the data related to the convex hull 300 and the extended hull 400, the controller 204 of the mustering UAV 200, at step 1300 of Fig. 3, navigates the mustering UAV 200 to a deployed position O _d on the extended hull 400 as shown in Fig. 7. In this embodiment, the deployed position O _d is determined to be the position on the extended hull 400 closest to the mustering UAV 200 based on the obtained position data of the mustering UAV 200.

[0064] At step 1400 of Fig. 3, after navigating the mustering UAV to the deployed position O _d , the controller 204 of the mustering UAV 200 prioritises the targeting of animals for herding by determining a steering point Sj, which is the extended hull vertex E _t associated with the convex hull vertex P _t located furthest from the centroid C _o . The controller 204 of the mustering UAV 200 then navigates the mustering UAV 200 along the extended hull 400 to the steering point Sj. Additionally or optionally, with reference to Fig. 7, the controller 204 of the mustering UAV 200 may also determine an optimal direction of travel (i.e., clockwise or anticlockwise) along the extended hull 400 that results in the shortest distance between the mustering UAV 200 and the steering point Sj. It will be appreciated that the mustering UAV 200 may have non-holonomic motion dynamics that allows the mustering UAV 200 to move along a short arc between adjacent straight-line edges 402 of the extended hull 400 during navigation, as best shown in Fig. 8. [0065] During navigation along the extended hull 400, the controller 204 of the mustering UAV 200 operates the speaker 212 to transmit the stored audio recording (e.g., the bark of a dog) towards the convex hull 300 so that the animals are urged to aggregate together. It will be appreciated that the animals that encounter the transmitted audio recording will turn away and exhibit a flight response by beginning to move. In this embodiment, the controller 204 of the mustering UAV 200 operates the stabiliser 214 such that the speaker 212 transmits the audio recording towards the centroid C _o regardless of the direction of travel of the mustering UAV 200. This urges the animals to move towards the centroid C _o of the convex hull 300 and therefore aggregate together.

[0066] Fig. 9 shows an example of the effective coverage of the transmitted audio recording for (a) a small predetermined distance d _s and (b) a larger predetermined distance d _s for the same plurality of animals 20. In this example, the transmitted audio recording has a broadcasting profile B that is cone-shaped with an angle fl and a distance R _b . It will be appreciated that the angle fl, the distance R _b , and the predetermined distance d _s may be adjusted depending on the circumstances, such as the size of the plurality of animals 20, for example.

[0067] The above method operations may be continuously performed over subsequent time periods until the animals are aggregated together. The animals may be considered to be aggregated together when the animal(s) located furthest from the centroid C _o are within a predetermined distance from the centroid C _o , for example.

Driving Strategy

[0068] After the animals are aggregated together, the system may also employ a driving strategy to urge the aggregated animals to move to a predetermined location, such as a sheepfold, for example.

[0069] With reference to Fig. 10, at step 2000, the controller 104 of the observer UAV 100 determines a minimum circular boundary 500 in two-dimensional space around the aggregated animals, hereinafter referred to as the herd 30, based on the captured image data. The circular boundary 500 has a centre C ₀₁ and a radius R defined by a distance between the centre C ₀₁ and the position of the animal of the herd 30 furthest from the centre C _ol , as best shown in Fig. 11.

[0070] Subsequently, at step 2100 of Fig. 10, the controller 104 of the observer UAV 100 determines an extended circular boundary 600 in two-dimensional space based on the circular boundary 500. The extended circular boundary 600 surrounds the circular boundary 500 and has a centre C _o2 that is the same as the centre C ₀₁ of the circular boundary 500, as best shown in Fig. 12. The extended circular boundary 600 also has a predetermined radius R _d that is larger than the radius R of the circular boundary 500. In one embodiment, the predetermined radius R _d is about 15 metres greater than R. In response to determining the circular boundary 500 and the extended circular boundary 600, the controller 104 of the observer UAV 100 transmits, via the communication system 110, data related to the circular boundary 500 and the extended circular boundary 600 to the mustering UAV 200. In some embodiments, the controller 104 of the observer UAV 100 may transmit data to the mustering UAV 200 related to the extended circular boundary 600 only.

[0071] The controller 204 of the mustering UAV 200 receives, via the communication system 208, data from the observer UAV 100 related to the circular boundary 500 and the extended circular boundary 600. In response to receiving the data related to the circular boundary 500 and the extended circular boundary 600, the controller 204 of the mustering UAV 200 at step 2200 of Fig. 10, determines a driving path £ on the extended circular boundary 600 on which the mustering UAV 200 navigates to urge the herd 30 to the predetermined location G. In this embodiment as shown in Fig. 13, the driving path £ is a semicircle of the extended circular boundary 600 with a line of symmetry <5 that extends through the centres C _ol , C _o2 and the predetermined location G. In other embodiments, the driving path £ may be any arc on the extended circular boundary 600 with a line of symmetry <5 that extends through the centres C _ol , C _o2 and the predetermined location G.

[0072] Subsequently, at step 2300 of Fig. 10, the controller 204 of the mustering UAV 200 navigates the mustering UAV 200 to oscillate between two end points Q _n , Q _n+1 on the driving path £. In this embodiment as shown in Fig. 14, the two end points Q _n . Q _n+1 are two end points on the diameter of the driving path £. However, it will be appreciated that the end points Q _n , Q _n+1 may be any two end points on the driving path £. [0073] During navigation, the controller 204 of the mustering UAV 200 operates the speaker 212 to transmit the stored audio recording towards the circular boundary 500. It will be appreciated that the herd 30 will be urged to move towards the predetermined location G at a speed V _animai upon encountering the transmitted audio recording. Oscillation of the mustering UAV 200 along the driving path L assists with maintaining the herd 30 within the circular boundary 500. It will also be appreciated that the mustering UAV 200 will move with the herd 30 towards the predetermined location G at a speed V _driving which is equal to or less than the speed V _animai of the herd 30.

[0074] In other embodiments, the controller 104 of the observer UAV 100 may instead navigate the mustering UAV 200 in accordance with the above method operations.

[0075] In some embodiments, the system may employ a single UAV to carry out all of the above described method operations.

[0076] The embodiments described above has numerous advantages. The system 10 provides an effective and efficient means for herding animals. In particular, the system 10 determines the convex hull 300 of the animals 20 in a predetermined area and efficiently gathers the animals by targeting animals located furthest from the centroid C _o of the convex hull 300. To determine the convex hull 300, the system 10 only requires the locations of the animals on the boundary, which significantly reduces the processing requirements of the system 10. Further, the system 10 employs UAVs that are able to rapidly and seamlessly traverse across vast terrain. Moreover, the mustering UAV 200 is able to urge the animals to move without any physical collisions, thus reducing the stress and harm of animals during herding. Further still, the stabiliser 214 of the mustering UAV 200 enables the speaker 212 to stably transmit the recorded audio recording in a desired direction (i.e., towards centroid C _o of the convex hull 300), regardless of the direction of travel of the mustering UAV 200.

[0077] In some embodiments, the system may employ a plurality of mustering UAVs 200 in communication with one or more observer UAVs 100. The system determines the convex hull 300 and the extended hull 400 in a similar manner described above. Each of the mustering UAVs 200 is also navigated to a deployed position O _d on the extended hull 400 in a similar manner described above. However, after navigating the mustering UAVs 200 to the deployed positions O _d , the system prioritises the targeting of animals for herding by first determining a plurality of steering points Sj corresponding to the extended hull vertices Ei that are associated with the convex hull vertices located furthest from the centroid C _o . The set of steering points .S' may be described as:

(3) S = {sj}, j = 1, ... , n _d where: n _d is the number of mustering UAVs 200; and

5 c £.

[0078] Subsequently, the system allocates each mustering UAV 200 to a respective steering point Sj, and then navigates each mustering UAV 200 to the respective steering point Sj . Additionally or optionally, the system may also determine an optimal direction of travel (i.e., clockwise or anticlockwise) along the extended hull 400 that results in the shortest distance between each mustering UAV 200 and the respective steering point Sj, and avoids collision of the mustering UAVs 200. During navigation, each of the mustering UAVs 200 transmits the stored audio recording (e.g., the bark of a dog) towards the convex hull so that the animals are urged to aggregate together. This allows multiple animals to be targeted at any one time, thus reducing the time associated with gathering.

[0079] After the animals are aggregated together to form a herd 30, the system determines the minimum circular boundary 500, the extended circular boundary 300 and the driving path L in a similar manner described above. However, the system additionally determines a plurality of driving path segments Lj in the driving path £ on which the mustering UAVs 200 navigate to urge the herd 30 to the predetermined location G. The system determines the driving path segments £j by determining a plurality of end points Qj spaced evenly along the driving path £. The set of end positions Q may be described as:

(4) Q = {Qj], j = l, ... , n _d+1 where: n _d is the number of mustering UAVs 200. [0080] The system then defines a driving path segment £j between two adjacent end points Qj, as shown in Fig. 15. Subsequently, the system allocates each mustering UAVs 200 to a respective driving path segment £j, and then navigates each mustering UAV 200 to oscillate within the respective driving path segment £j . During navigation, each of the mustering UAVs 200 transmits the stored audio recording (e.g., the bark of a dog) towards the circular boundary 500 so that the herd 30 is urged to move towards the predetermined location G.

[0081] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.