Device for spreading granulated product and method of detecting spreading pattern of granulated product spread from a device

Abstract

A device (171) for spreading at least one granular product to ground over which the device travels. The device comprises a spreading disc (203) configured to rotate in a generally horizontal plane, a product supply (202) configured to feed product (201) onto the spreading disc, while the spreading disc is caused to rotate, to form a spreading pattern (218) of granules, a detector (204), configured to provide a detection plane (205) of electromagnetic radiation, which is approximately parallel with and below the horizontal plane. The detector is configured to detect points of intersections between the detection plane and product granules. And a method of detecting a spreading pattern of granular product spread from a device. Wherein the device comprises a spreading disc, a product supply, and a detector configured to provide a detection plane of electromagnetic radiation below a generally horizontal rotation plane of the spreading disc.

Description

[0001] DEVICE FOR SPREADING GRANULATED PRODUCT AND METHOD OF DETECTING SPREADING PATTERN OF GRANULATED PRODUCT SPREAD FROM A DEVICE

[0002] Technical field

[0003] The present disclosure relates generally to the use of unmanned aerial vehicles ("UAVs") in agriculture, and in particular to distribution of one or more products in powder or granular form to an area over which the UAV flies.

[0004] Background

[0005] In agriculture it is common to use added product or substance, such as fertilizer, fungicide, herbicide or pesticide to improve the yield from the crops or to prevent weeds or pests. Other products may include minerals, chalk or seeds. The product may be in granulated, powdered, or liquid form.

[0006] Different distribution techniques exist for product of the different forms. The product is commonly spread from agricultural implements which may be mounted on, or towed behind, a tractor or other type of self-propelled vehicle.

[0007] A common problem for traditional ground-based spreading techniques is the inevitable tramlines needed. Tramlines decrease the arable field area and increase soil compaction locally.

[0008] Moreover, ground-based spreading may be difficult when fields are wet, as machines tend to sink and get stuck. Also, tramlines tend to further erosion, in particular on sloping fields, where soil is led away by water flowing in the tramlines.

[0009] In some areas, airborne spreading is practiced by airplanes or helicopter, however, such practices are costly, and in many areas, such practices are not permitted.

[0010] Moreover, airborne spreading is generally associated with a lack of precision, due to the height and speeds at which it is carried out.

[0011] Another common problem for the spreading techniques is the effect from wind or hilly field conditions, which may interfere with the desired spreading pattern from a spreader in a negative way. The fact that different products may present different spreading characteristics may also cause problem. Rain may also cause problems, limiting the ability for tractors or other ground-based vehicles to get traction in field.

[0012] Hence, there has arisen an interest in the use of UAVs or "drones" equipped with spreader units for spreading various products.

[0013] While one line of development in the field of agricultural UAVs is to use a large number of small UAVs, another line of development is to use fewer but larger UAVs. For example, a larger UAV for distribution of agricultural product may have a distribution width of about 10-15 m and a load capacity of about 100-1000 kg.However, the use of UAVs in agriculture is still in its infancy and hence there is a need for improvements in their capabilities, operation and in their precision.

[0014] Summary of invention

[0015] It is an objective of the present disclosure to provide solutions which eliminate or alleviate at least some of the disadvantages mentioned above.

[0016] The invention is defined by the appended independent claims. Embodiments are set forth in the appended dependent claims, in the following description and in the attached drawings.

[0017] According to a first aspect, there is provided a method for detecting a spreading pattern from a distribution device distributing granular product to an area. The method comprises causing a spreading disc of the device to rotate in a plane generally parallel to the ground over which the device travels, feeding product from a product supply to the spreading disc such that the product is thrown by the rotating spreading disc to form a spreading pattern, operating a detector comprising a sensor, in particular a lidar sensor, to provide a detection plane, wherein said detector is arranged vertically below the spreading disc, and wherein said detection plane is angled, preferably upwardly from the detector, towards an intersection between the detection plane and the spreading pattern, detecting the spreading pattern by registering a distance between the detector and the intersection.

[0018] In the method, the granular product may be an agricultural granular product, such as seeds, fertilizer, pesticide, herbicide or fungicide.

[0019] Providing a detection plane may comprise transmitting, from the detector, a first laser beam, transmitting, from the detector, a second laser beam, wherein the second laser beam is separated from the first laser beam by an angle.

[0020] The angle VI may be in the same plane as the rotation plane of the spreading disc. The angle VI may be in a horizontal plane.

[0021] Registering a distance between the detector and the intersection may comprise receiving a reflection of the first laser beam, reflecting off one or more granules of the spreading pattern, calculating a distance to the reflecting granule(s) by time-of-flight calculation of the first laser beam, receiving a reflection of the second laser beam, reflecting off one or more granules of the spreading pattern and calculating a distance to the reflecting granule(s) by time-of-flight calculation of the second laser beam.

[0022] The method may further comprise operating the device to travel back-and-forth over an agricultural area in non-overlapping paths, while distributing granulated product and detecting the spreading pattern.

[0023] The non-overlapping paths are preferably arranged such that the spread product effectively covers the entire agricultural area.The non-overlapping paths may comprise a first straight path, followed by a 180 degree turn, followed by a second straight path, where the second straight path is laterally spaced from the first straight path.

[0024] Operating the device to travel may comprise mounting the device to an unmanned aerial vehicle, "UAV", and causing the UAV to fly over the agricultural area.

[0025] According to a second aspect, there is provided a device for spreading a granular product to ground over which the device travels, the device comprising a spreading disc configured to rotate in a plane generally parallel to the ground over which the device travels, a product supply configured to feed product onto the spreading disc, while the spreading disc is caused to rotate, to form a spreading pattern of granules, a detector including a lidar sensor, configured to provide a detection plane comprising angularly separated laser beams, wherein the detector is arranged vertically below the spreading disc, and wherein the detection plane is angled upwardly from a center of the detector to an intersection between the detection plane and the spreading pattern, wherein the detector is further configured to detect points of intersections between the detection plane and product granules within the spreading pattern.

[0026] According to a third aspect, there is provided an unmanned aerial vehicle, "UAV", comprising the device (171) described above, wherein the UAV comprises a frame, one or more rotatable rotors, and wherein the device is mounted to the frame at a lowermost portion thereof.

[0027] According to a fourth aspect, there is provided an UAV as described above, wherein the UAV further comprises an elongated spreader unit support, wherein a proximal portion of the spreader unit support is connected to the frame of the UAV, and wherein the device is mounted to a distal portion of the spreader unit support, such that the device is supported outside a footprint of the UAV, as seen in a horizontal plane.

[0028] A footprint of the UAV may be defined by the outer periphery of the UAV, as seen in a horizontal plane.

[0029] The footprint of the UAV may coincide with an air column affected by downwash caused by the rotors of the UAV.

[0030] According to a fifth aspect, there is provided a device for spreading at least one granular product to ground over which the device travels. The device comprises a spreading disc configured to rotate in a generally horizontal plane, a product supply configured to feed product onto the spreading disc, while the spreading disc is caused to rotate, to form a spreading pattern of granules, a detector, configured to provide a detection plane of electromagnetic radiation, which is approximatelyparallel with and below the horizontal plane. The detector is configured to detect points of intersections between the detection plane and product granules.

[0031] The detector may provide a detection plane by transmitting multiple electromagnetic waves, in particular beams, to form a common plane. The electromagnetic wavelength may be near the infrared spectrum.

[0032] The detector may be a lidar detector.

[0033] The detector may be configured to provide one detection plane comprised by multiple electromagnetic waves, or beams.

[0034] The product is granular in that it comprises multiple individual granules. The granules may be of different forms and sizes. The granules may be of different forms and sizes within the same batch of granules. The granules may be of different forms and sizes between different granular product types. Some granules may be small enough to be referred to as powder.

[0035] Granular products may be agricultural products such as seeds or fertilizer, pesticides, fungicide, herbicide, or snail poison. It may also be product for lawn keeping such as topdressing. It may also be product for winter road maintenance such as salt, grit, or gravel.

[0036] By generally horizontal plane is hereby meant a plane that ideally is horizontal. However, the plane may deviate from a horizontal plane when the device is tilted. The device may be tilted due to ground irregularities, or to provide a desired spreading pattern. The device may also be tilted due to incorrect horizontal adjustments on the device.

[0037] Generally horizontal is hereby also meant that the spreading disc may actively adjust for ground contours or borders. The approximately horizontal plane may be parallel to the ground over which the device currently travels. In particular, the approximately horizontal plane may be parallel to the ground over which the device travels such that a rotation axis of the spreading disc is parallel to a normal of a plane that tangents the ground over which the device travels.

[0038] A spreading pattern may be a shape of an amount of product granules as seen from above, either at a specific point in time, or accumulated over a predetermined time period. The spreading pattern may be formed by product granules being thrown from the spreading disc in a radial direction.

[0039] In its most simple form, the spreading pattern may provide a number of directions and distances to a plurality of granules, as per above.

[0040] The spreading pattern may comprise parameters of a distance and a direction between product granules and a spreading disc rotation centre.

[0041] The detection plane is approximately parallel to the horizontal plane in that it may adjust for ground contours.The detector, and thereby the detection plane, may be adjustably or non-adjustably connected to the device. By being non-adjustably connected to the device an orientation of the detector is fixed in relation to an orientation of the device, or a carrier of the device.

[0042] The detector may alternatively be adjustably connected to the device. In particular, it may be connected such that an orientation of the detector follows an orientation of the spreading disc. This may be preferable since the detection plane may be adjusted to follow ground contours.

[0043] With information about an orientation and position of the spreading disc and orientation of the detection plane, information about how the spreading pattern is oriented in relation to the ground may be derived. Relative angles of the spreading disc, the detector and the ground may be adjusted for mathematically in a control system.

[0044] A detection plane may be provided by transmitting from the at least one detector multiple laser beams, with angular displacements between each other, in a common plane. The shape of the detection plane may be a circle sector. The at least one detector may be at the centre of the circle sector. The circle sector may be a full circle.

[0045] A point of intersection is a point in the detection plane where a product granule passes the detection plane to create a by the detector detectable reflection.

[0046] By providing a detection plane below the spreading disc, all granules ejected by the spreading disc will at some point pass through the detection plane, the extent of which is well known, such that data, e.g. in the form of range and direction, of each such granule passage can be collected. By accumulating a number of such data, a spreading pattern can be derived, thus providing information about the spreading performance of the spreading disc.

[0047] The detector may be supported by the device via a tilt arrangement. The tilt arrangement may be configured to allow angular displacement of the detector around at least one geometric axis.

[0048] By being carried by the tilt arrangement the detector may be tilted together with the spreading disc. The detector may be tilted such that the detection plane is parallel to the approximately horizontal plane of the spreading disc.

[0049] The detector may be vertically spaced from the spreading disc, such that the detector is provided closer to the ground than the spreading disc in a working mode.

[0050] By decreasing the distance from the detection plane to the ground a more accurate registering of the spreading pattern may be achieved.

[0051] An accurate registering may be when the registered spreading pattern equals the distribution pattern of product that lands on the ground. By decreasing the distance between the detection plane and the ground a difference between theregistered spreading pattern and the distribution pattern of product on the ground may be minimized.

[0052] A centre of the detection plane may be arranged vertically under the spreading disc.

[0053] The centre of the detection plane may be arranged coaxially with a rotation axis of the spreading disc.

[0054] The centre of the detection plane may be arranged laterally and / or longitudinally displaced from a rotation axis of the spreading disc, referring to a working direction.

[0055] By having the rotation of the spreading disc concentric with the centre of the detection plane, distance calculations from the centre of the spreading disc to the points of intersections may be facilitated.

[0056] The detection plane may be provided by at least one laser beam transmitted from the detector, and the detector may comprise a receiver configured to receive reflections of the at least one laser beam.

[0057] A possible associated advantage of providing the detection plane as an array of laser beams is the laser beam's generally good penetration capability through rain and dust. This may improve the detection capability of granules during challenging conditions.

[0058] The array of laser beams may be provided by one detector which is caused to oscillate or rotate.

[0059] The array of laser beams may be provided by multiple detector generating laser beams with angular displacement between each other.

[0060] The detector may be further configured to detect obstacles intersecting the detection plane.

[0061] Obstacles may be ground based constructions such as building, fences, power line posts or wind turbines. Obstacles may also be organic matter such as trees, bushes, wildlife, or cattle.

[0062] The detector may comprise, or be connected to, a processing unit configured to accumulate points of intersections to register the spreading pattern of granules.

[0063] The processing unit may be the onboard controller.

[0064] By registering the spreading pattern any irregularities or asymmetries of the spreading pattern may be detected. Such irregularities or asymmetries could occur e.g. due to a change of product shape or density, to a change in weather conditions such as wind or rain, or a change in spreading rate demanded from a spreading rate controlling system.

[0065] The detector may comprise, or be connected to, a processing unit further configured to compare the registered spreading pattern to a predetermined spreading pattern.A predetermined spreading pattern may be a symmetrical spreading pattern. A symmetrical spreading pattern may be formed such that spread product intersect the detection plane at equal radial distance from a rotation centre of the spreading disc.

[0066] By comparing the spreading pattern to a predetermined spreading pattern, any deviations from an optimal spreading pattern may be detected. The predetermined spreading pattern may be provided manually or by a spreading pattern providing system.

[0067] The detector may be further configured to control at least one spreading parameter actuator to adjust the spreading pattern to provide the predetermined spreading pattern.

[0068] The spreading pattern may be actively adjusted by a control system. Meaning the spreading pattern may be adjusted in real-time. This may allow for the spreading pattern to be adjusted according to, for example, rapid winds or gusts.

[0069] Non-limiting examples of spreading parameter actuators may be a spreading disc drive for rotational speed of the spreading disc, an opening actuator for feeding position of product from the product supply onto the spreading disc, an aperture actuator for feeding rate of product from the product supply, a tilt actuator for angle of the spreading disc in relation to a horizontal plane, or height adjustment actuator for the device.

[0070] By adjusting the spreading pattern according to a predetermined spreading pattern an optimal spreading pattern may be achieved, providing optimal distribution of product to improve the yield.

[0071] The detector may be further configured to provide information of a detected obstacle to a spreading control unit. And the spreading control unit may be configured to adjust a spreading parameter actuator to adapt the spreading pattern in accordance with the detected obstacle.

[0072] A spreading control unit may be an onboard controller of the device, or a remotely connected processing unit. The spreading control unit may be integrated within a processing unit performing other tasks for the device. The spreading control unit may be, or be in contact with, the onboard controller.

[0073] Adjustment of the spreading pattern in accordance with the detected obstacle may be advantageous to avoid spreading in prohibited or unsuitable areas.

[0074] The detector may be further configured to provide information of a detected obstacle to an onboard controller. And the onboard controller may be configured to inform about, or adjust a travel route of the device to avoid, the detected obstacle.

[0075] The detector may provide information about a detected obstacle such that a user or an automated system may avoid collision.The spreading disc may be caused to rotate by a spreading disc drive operably coupled to the spreading disc to provide rotational movement.

[0076] The spreading disc drive may control the spreading disc to different rotational speeds. By changing the rotation speed of the spreading disc, different spreading characteristics may be achieved.

[0077] The spreading disc may be arranged on the tilt arrangement.

[0078] It may be advantageous for the spreading disc to be provided parallel to the ground over which the device currently travels. This may enable equal time of flight and also equal distance of flight for each granule of product spread from the spreading disc, reducing the risk of too short spreading uphill and too far spreading downhill. Equal flight distance for each granule may provide a predictable spreading pattern regardless of any ground irregularities such as hills or undulations.

[0079] The tilt arrangement may comprise a lateral actuator configured to tilt about a first pivot axis which is parallel to a working direction.

[0080] The detector and / or the spreading disc may be tilted by the tilt of the tilt arrangement.

[0081] By being laterally angled the spreading disc may form a spreading pattern which is asymmetrical over a vertical plane comprising a working direction of the device. This may facilitate adaption to ground undulations.

[0082] The tilt arrangement may comprise a longitudinal actuator configured to tilt around a second pivot axis which is perpendicular to a working direction.

[0083] By being longitudinally angled the spreading disc may form a spreading pattern which is asymmetrical over a vertical plane perpendicular to a working direction of the device. This may facilitate adaption to ground undulations.

[0084] The tilt arrangement may further comprise a ground measurement sensor. And the ground measurement sensor may be configured to provide information of the ground surface over which the device currently travels.

[0085] The ground measurement sensor may be a contactless sensor, such as a radar or a lidar sensor.

[0086] Information of the ground surface may be ground contours. Specifically, it may be an orientation of a plane which tangents the ground surface over which the device currently travels in relation to a horizontal plane.

[0087] The tilt arrangement may be configured to control one or more of the lateral actuator and the longitudinal actuator in response to ground measurements provided by the ground measurement sensor.

[0088] Adjustment of the tilt arrangement is preferably such that the spreading disc is parallel to the ground. This may improve the spreading performance in hilly conditions.

[0089] The spreading disc may present a concave shape.A concavely shaped spreading disc may achieve a longer throw for the same rotational speed of the spreading disc, since it may provide an upwards trajectory for the product leaving the spreading face.

[0090] The spreading disc may comprise radial guides, configured to guide the product approximately radially outwardly from the disc.

[0091] Radial guides may increase the throwing distance of the spreading disc for a given rotational speed.

[0092] The product may be fed from the product supply onto the spreading disc through a controllable product aperture.

[0093] The product aperture may be configured to control the feeding rate of product. By changing the feeding rate different spreading characteristics may be achieved.

[0094] The product aperture may be controllably movable above the spreading disc by an opening actuator, such that a feeding position of product from the product supply onto the spreading disc may be controlled.

[0095] By moving the product aperture over the spreading disc to control the feeding position of product onto the spreading disc, different spreading characteristics may be achieved.

[0096] An unmanned aerial vehicle, "UAV", may comprise a device according to above.

[0097] The device may be supported by a spreading unit support which presents an elongated extension, wherein the spreading disc may be carried at a distal portion of the spreading unit support. A proximal portion of the spreading unit support may be connected to a frame such that the spreading unit support provides the spreading disc outside, as seen in a horizontal direction, of a downwash area of the UAV 1.

[0098] The elongated spreading unit support may present a vertical and / or a horizontal displacement between its proximal portion and its distal portion.

[0099] A downwash area may be an area in a horizontal plane underneath the UAV that in flight mode is affected by an air stream caused by propellers of the UAV. Such air stream may affect a spreading pattern of granulated product. Downwash is typically presented as a column underneath the UAV.

[0100] By providing the spreading disc outside of a downwash area the impact from the downwash airstream on the spreading pattern may be reduced, providing a more predictable spreading pattern.

[0101] The spreading unit support may comprise a product feed along its elongated extension.

[0102] The spreading unit support may comprise or support a product feed along its elongated extension, such as a hose, tube or pipe. The spreading unit support may comprise the product feed in its self-supporting structural design. The product feedmay be configured to feed product from a proximal end of the product feed to a distal end of the product feed. The product feed may present a physical link between the product supply and the spreading disc.

[0103] The device may comprise a single spreading disc.

[0104] Advantages of having only one spreading disc may be that power requirements for spreading product are kept at a minimum.

[0105] An agricultural implement may comprise a frame and a device according to above connected to the frame.

[0106] The frame may comprise a linkage for being mounted to a traction vehicle. Linkage for being mounted to a traction vehicle may be a 3-point hitch connector. Mounted is hereby meant supported by the traction vehicle without ground support.

[0107] The frame may comprise a connector, for being towed by a traction vehicle, and one or more ground supports.

[0108] Connector for being towed by a traction vehicle may include a 3-point hitch connector, a 2-point hitch connector, or a trailer coupling such as a sprint coupling or a hook coupling. Ground supports may be wheels or tracks.

[0109] According to a sixth aspect, there is provided a method of detecting a spreading pattern of granular product spread from a device. Wherein the device comprises a spreading disc, a product supply, and a detector configured to provide a detection plane of electromagnetic radiation below a generally horizontal rotation plane of the spreading disc. The method comprises feeding product from the product supply onto the spreading disc, causing the spreading disc to rotate, in an approximately horizontal plane, to form a spreading pattern of granules, providing, by the detector, the detection plane, detecting, by the detector, points of intersections between the detection plane and product granules.

[0110] The detector may transmit electromagnetic waves, or beams. The detector may receive reflections from the transmitted electromagnetic waves, or beams. The electromagnetic wavelengths may be near the infrared spectrum.

[0111] The detector may be a lidar detector.

[0112] Detecting points of intersections may comprise accumulating data of a plurality of points of intersection to form the spreading pattern.

[0113] The method may further comprise the subsequential steps of comparing the detected spreading pattern to a predetermined spreading pattern and adjusting the spreading pattern to provide the predetermined spreading pattern by controlling one or more spreading parameter actuators.

[0114] The spreading disc may be caused to rotate by a spreading disc drive operably coupled to the spreading disc to provide rotational movement.The detection plane may be approximately parallel to a rotation plane of the spreading disc.

[0115] The detection plane may be provided by at least one laser beam transmitted by the detector, and reflected light from product granules may be received by the detector.

[0116] The device may be carried by an unmanned aerial vehicle, "UAV". And an initiating step may comprise causing the UAV to fly over ground to which the granular product is to be spread.

[0117] The device may be arranged on a frame of an agricultural implement which is configured to be coupled to a traction vehicle. And initiating steps may comprise connecting the agricultural implement to a traction vehicle, and causing the traction vehicle to drive over ground onto which the product is to be spread.

[0118] The frame may comprise a linkage for being mounted to an agricultural tractor.

[0119] The frame may comprise a connector, for being towed by an agricultural tractor, and one or more ground supports.

[0120] The granular product may be agricultural product.

[0121] The granular product may be fertilizer or seeds.

[0122] According to a seventh aspect, there is provided a spreader unit for use in an unmanned aerial vehicle ("UAV") for spreading an agricultural product to an area over which the UAV travels, the spreader unit comprising a product tank, a spreader device, configured for spreading the product, and a spreader unit support, configured to extend between the product tank and the spreader device, wherein the spreader unit support comprises a release device, configured to allow for a distal portion of the spreader unit support to separate from a proximal portion of the spreader unit support, in particular upon a collision between the spreader device and an obstacle.

[0123] The release device may be provided closer to the product tank than to the spreader unit.

[0124] The release device may comprise a pair of connectors, which are releasably held together by at least one of a rupture device, a spring-loaded device, magnetic force device and an adhesive device.

[0125] The release device may provide a joint plane), which provides a joint angle relative to a longitudinal direction of the spreader unit support, said joint angle providing an acute angle, and in particular an angle that is no more than 60 degs, preferably no more than 45 degs or no more than 30 degs.

[0126] The spreader unit may further comprise a locking mechanism configured for selectively preventing separation of the distal portion of the spreader unit support from the proximal portion of the spreader unit support.The locking mechanism may be configured to prevent or allow said separation in dependence of an orientation of the spreader unit support.

[0127] According to an eighth aspect, there is provided an unmanned aerial vehicle comprising a spreader unit as described above.

[0128] Fig. 1 schematically illustrates an unmanned aerial vehicle, "UAV".

[0129] Fig. 2 schematically illustrates a UAV provided with a device for spreading granular product.

[0130] Fig. 3 schematically illustrates a sideview of a device for spreading granular product.

[0131] Fig. 4a-4b schematically illustrates a top view of a device for spreading granular product arranged on a UAV.

[0132] Fig. 5 schematically illustrates a traction vehicle and an agricultural implement according to an exemplifying embodiment.

[0133] Fig. 6 schematically illustrates a traction vehicle and an agricultural implement according to an exemplifying embodiment.

[0134] Fig. 7 schematically illustrates a flow chart of a method of detecting a spreading pattern of granulated product.

[0135] Fig. 8 schematically illustrates a sideview of a device for spreading granular product, according to an exemplifying embodiment.

[0136] Fig. 9 schematically illustrates a top view of a lidar sensor providing a detection plane.

[0137] Fig. 10 schematically illustrates a side view of a lidar sensor providing a detection plane.

[0138] Figs lla-llb schematically illustrate an embodiment of a spreader unit support.

[0139] Figs 12a-12b schematically illustrate an embodiment of a spreader unit support.

[0140] Detailed description

[0141] Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0142] The terms "a" and "an" are used herein to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article. By way of example, "an element" means one element or more than one element.In the context of this specification, modifying terms, such as "about", "approximately" and "substantially" are understood to refer to a range of numbers that a person of skill in the art would consider equivalent to the recited value in the context of achieving the same function or result. Any value, range or term thus modified is to be understood as being disclosed also without the modifying term.

[0143] Referring to Fig. 1, an unmanned aerial vehicle ("UAV") 1, commonly known as a "drone", is an aircraft that operates without a human pilot on board. UAVs can be controlled remotely by a human operator and / or autonomously by onboard computers.

[0144] While UAVs may come in many different designs and configurations, in the present disclosure, the UAV will, as a non-limiting example, be assumed to comprise the following systems.

[0145] An UAV 1 would typically comprise an airframe 11, i.e. the structure of the UAV, which includes the body, wings (if any), and landing gear 113. It provides the necessary support and shape for the drone. In the illustrated example, the airframe comprises a central and generally horizontally extending web 111 and a pair of generally horizontally extending flanges 112, end portions of which provide corners of a rectangle at which rotors are positioned.

[0146] An UAV 1 would typically also comprise a propulsion system 121, 122, which would include the motor(s)121, rotor(s) 122, and sometimes jet engines, which generate the thrust needed for the UAV 1 to fly.

[0147] The propulsion system may also comprise a transmission system (not shown), for transferring mechanical power from one or more motors 121 to one or more rotors 122.

[0148] An UAV 1 would typically also comprise a power source 13, such as a battery or fuel system that provides the energy required to power the UAV's systems and propulsion.

[0149] An UAV 1 would typically also comprise a flight control system 14, which would include the onboard computer and sensors (such as gyroscopes and accelerometers) that help stabilize and control the UAV during flight.

[0150] An UAV 1 would typically also comprise a communication system 15, which allows the UAV to communicate with the ground control station (ground controller 40) or operator, enabling remote control and / or data transmission.

[0151] An UAV 1 would typically also comprise a navigation system 16, including Global Navigation Satellite System (GNSS) and / or other sensors that help the UAV 1 determine its position and navigate to its destination.

[0152] The navigation system may also include gyro(s) and accelerometer(s) for inertial navigation, which may be used in case of limited availability of GNSS.An UAV 1 would typically also comprise a payload 17, which, depending on the UAV's purpose, can include cameras, sensors, delivery packages, or other equipment that the UAV is designed to carry.

[0153] An UAV 1 may comprise a local beacon detector 18, which may be used for connecting to and navigating by a local beacon 181, which may be arranged on or at the airbase 3.

[0154] An UAV 1 may also comprise one or more cameras 19 for capturing images that can be used for manual flight, for navigation and / or for inspection. In particular, it may be desirable to provide one or more cameras having night vision capability, e.g. by having capability to pick up light in the infra-red spectrum.

[0155] In particular, one or more cameras 19 may be positioned to provide a view of a spreader unit, such that the distribution operation can be monitored, either in real-time or later.

[0156] The UAV 1 may also have one or more sensors for collision avoidance, such as radar sensors, lidar sensors, ultrasound sensors, laser sensors or cameras.

[0157] The various systems controlling the flight, navigation, communication and operation of the UAV 1 may be provided as separate systems, or as a wholly or partially integrated system, collectively referred to as a "onboard controller" 14, 15, 16.

[0158] A special case may be that the payload 17 has its own control system, although such control system would need to communicate with the onboard controller 14, 15, 16 or with the ground controller 40, e.g. when a need to replenish product is detected. A payload controller 172 may be a separate unit or integrated with the onboard controller 14, 15, 16. The payload controller 172 may control payload features. Payload features may depend on the payload 17, and may include actuators or valves for dispensing a product and sensors for sensing product level and / or for evaluating the dispensing process.

[0159] An UAV 1 would typically also require a controller 40, which comprises the interface used by the operator to control the UAV, which can be a handheld controller, a computer, or a more complex setup for larger UAVs.

[0160] Typically, all actuators and / or sensors may be connected to the onboard controller, to enable the onboard controller to make autonomous decisions and / or for communication to / from the ground controller 40.

[0161] In some embodiments, communication may be only between the UAV 1 and the airbase 3, with all control functions being provided at the airbase 3, e.g. through the ground controller 40. In such embodiments, on-site operator control and / or supervision would be necessary.

[0162] In some embodiments, additional communication may be to a central control and / or monitoring site, such as via a direct communication link or via a cloud-basedsystem. In such embodiments, the airbase 3 may operate as a gateway, such that the UAV 1 communicates with the airbase 3 and the airbase 3 forwards communication to / from the UAV 1 from / to a remote control site. In such embodiments, an operator could control and / or monitor several airbase / UAV systems remotely and / or ambulatory.

[0163] In some embodiments, the airbase 3 and the UAV 1 may both communicate with a central control site, such as via a direct communication link or via a cloudbased system. This would also allow an operator to control and / or monitor several airbase / UAV systems remotely and / or ambulatory.

[0164] The communication may utilize cellular and / or satellite-based communication technology. Optionally wlan functionality may be used by the airbase 3, if available where the airbase 3 is stationed.

[0165] Data processing and / or storage may be provided at the airbase 3, in a remote server and / or control site and or by cloud-based computing / storage.

[0166] In the present context, it is contemplated that the UAV 1 would be sized and adapted for payloads 17 in excess of 100 kg, preferably in excess of 200 kg or in excess of 400 kg. Such UAV platforms are commercially available, e.g. in a quadcopter configuration with a generally H-shaped airframe and a petrol- or jet fuel-powered turboshaft engine.

[0167] The payload may comprise a spreader device 171 for spreading a liquid or solid product 201 to ground over which the UAV travels. The spreader device 171 may comprise one or more product tanks 170, a spreader unit 1711 and a spreader unit support 1712, which extends such that the spreader unit 1711 is situated outside an area of downwash from the rotors 122. The spreader unit 1711 may comprise one or more spreader discs (not shown) for spreading a solid (powdery or granular) product 201, such as fertilizer, pesticide, herbicide, fungicide, seeds, or a combination thereof. Alternatively, the spreader unit 1711 may comprise a sprayer boom for spreading a liquid product, such as fertilizer, pesticide, herbicide, fungicide, or a combination thereof.

[0168] The spreader unit support 1712 may comprise, or support, a product feed along its extension (not shown). The product feed may feed product 201 from a product tank 170 to the spreader unit 1711. The product feed may comprise controlled feeding members, such as an auger. Alternatively, the product feed may be a tube or hose for product 201 to fall freely within. The product feed may be a structural support forming a physical connection between the frame 111 and the spreading unit 1711. The feeding of product 201 may be done inside a structural support.

[0169] The product tank 170 may be provided with a product level sensor. For example, a weight sensor, a pressure sensor, an optical sensor, a radar sensor, alidar sensor, a magnetic sensor or an ultrasonic sensor may be used to detect the level of solid product 201 in the product tank 170.

[0170] Hence, the UAV 1 may detect a low product level in the product tank 170, which may trigger the UAV 1 to return to the airbase 3 for replenishment.

[0171] As illustrated, the spreader device 171 may extend outside the downwash area from the rotors 122, such that the spreader device also defines a forward working direction Dw of the UAV 1. Optionally, the spreader device 171 may also extend downwardly from the UAV, preferably below a landing gear 113. Hence, the spreader device 171 extends outwardly from the airframe 111, 112 towards a direction which is the working direction Dw.

[0172] Alternatively, the product level sensor may be dispensed with. Instead, a product feed sensor may be provided in the spreader unit, e.g. in the form of a detector (typically optical or acoustic) for detecting flow of the product 201 in the channel of the spreader unit 171.

[0173] Hence, the UAV 1 may detect that the product flow in the channel has ceased, which may trigger the UAV 1 to return to the airbase 3 for replenishment.

[0174] Referring to Fig. 2 an exemplifying embodiment of an unmanned aerial vehicle, "UAV", 1 is illustrated. The UAV 1 comprises with a device 171. The device 171 may be configured to spread granulated product to form a spreading pattern 218. A detector 204 of the device 171 may further be configured to provide a detection plane 205. The detection plane 205 is preferably provided under a spreading disc 203 of the device 171.

[0175] The device 171 may comprise a detector 204 which is configured to transmit electromagnetic radiation to form the detection plane 205. The detector 204 is further configured to receive reflections from granulated product falling through the detection plane 205 and to measure a distance to the reflected granule. The distance may be measured by time-of-flight measurement of the transmitted and received electromagnetic radiation.

[0176] The device 171 may be further configured to detect obstacles 211 within the detection plane 205.

[0177] The description will now be directed to a device 171, which is configured for spreading a solid, and in particular granular or powdery product.

[0178] Referring to Fig. 3, the exemplifying device 171 comprises a spreading disc 203. The spreading disc 203 may be generally circular. The spreading disc 203 may be caused to rotate by a spreading disc drive 207. When caused to rotate the spreading disc 203 is enabled to spread granular product 201 generally radially from the spreading disc 203 to form a spreading pattern 218.

[0179] The spreading disc 203 may be concave. The concave shape may be a round or a conical concave shape. The concave shape may preferably be symmetrical. Theconcave shape may preferably be symmetrical by having a constant slant height from the vertex to all points along the outside of the base.

[0180] The device 171 in Fig. 3 is provided with only one spreading disc 203.

[0181] However, this is a non-limiting example. The device 171 may be provided with one or more spreading discs 203, in particular two spreading discs 203. The one or more spreading discs 203 may be arranged to rotate in a common generally horizontal plane. Rotational axes of the one or more spreading discs 203 may be radially displaced from each other in a common horizontal plane. The one or more spreading discs 203 may be caused to rotate by one or more spreading disc drives 207. One spreading disc drive 207 may be arranged to cause one spreading disc 203 to rotate. Alternatively, one spreading disc drive 207 may be arranged to cause multiple spreading discs 203 to rotate, e.g. with a belt between rotation axes of the multiple spreading discs 203.

[0182] Multiple spreading discs 203 may be caused to rotate in a common rotation direction, or in an opposite rotation direction in relation to each other.

[0183] Radial guides 206 may be arranged on the spreading disc. The radial guides 206 may provide a long throwing distance and a predictable trajectory for the spreading of product 201.

[0184] A product supply 202 may be arranged above the spreading disc 203. The product supply 202 may be configured to controllably release product 201 onto the spreading disc 203.

[0185] A product aperture 209 may be arranged at an outlet of the product supply 202. The product aperture 209 may control a size of the outlet from the product supply 202. The product aperture 209 may control a feeding rate of product 201 released onto the spreading disc 203.

[0186] An opening actuator 210 may be arranged at the outlet of the product supply 202. The opening actuator 210 may control a position where product 201 is released onto the spreading disc 203.

[0187] The opening actuator 210 may be integrated with the product aperture 209. The product aperture 209 and the opening actuator 210 may be arranged as controllable hatches or gates at a product outlet. The hatches or gates may be configured to control both an opening size of a product outlet and a release position of product 201 onto the spreading disc 203. For example, this may be realized by a long product outlet with controllable hatches configured to close or open the outlet from two opposing sides.

[0188] The spreading disc 203 may be arranged on a tilt arrangement 215. The tilt arrangement 215 may be configured to tilt the spreading disc 203 around at least one geometric pivot axis Al, A2. The tilt of the spreading disc 203 may be advantageous during hilly ground conditions.In the case where the device 171 comprises more than one spreading disc 203, each spreading discs 203 may be individually adjustable. Alternatively, spreading discs may be pairwise arranged fixedly relative to each other but adjustable relative to the device 171.

[0189] The device 171 may further be arranged with a ground measurement sensor 213. The ground measurement sensor 213 may provide information about distance to ground and ground parameters, such as contours or undulations.

[0190] A control system may be arranged on the device. The control system may be in communicative connection with sensors and actuators of the device. In particular, the control system may adjust a spreading parameter to adapt a spreading pattern 218.

[0191] Furthermore, a detector 204 is arranged on the device 171. Preferably the detector 204 is arranged below the spreading disc 203. When the spreading disc 203 is arranged on a tilt arrangement 215 the detector 204 may be arranged on the tilt arrangement 215.

[0192] The detector 204 is configured to provide a detection plane 205 of electromagnetic radiation to be reflected by granules ejected by the spreading disc(s) 203 when they fall through the detection plane 205.

[0193] In the present disclosure, the detection plane 205 is provided by means of laser light, which may be pulsed, e.g. as a beam pattern or as one or more scanning beams. In particular, the detector may be a LiDAR (Light Detection and Ranging) type detector.

[0194] The detection plane 205 may ideally be horizontal or parallel to the ground over which the device 171 travels. The detection plane 205 may be adjusted to ground contours when arranged on the tilt arrangement 215. Alternatively, the detection plane 205 may be adjusted by tilting of the device 171.

[0195] Hence, the detector 204 may be movable with the disc 203 in accordance with at least one of the pivot axes Al, A2.

[0196] Alternatively, the detector 204 may be fixedly arranged relative to the device, such that the disc 203 is movable relative to the detector 204.

[0197] The spreading disc drive 207 may be a rotary actuator. The rotary actuator may be an electrical or hydraulic motor. The spreading disc drive 207 may comprise a motor axis to which the spreading disc 203 is mounted. The spreading disc 203 may be mounted such that a rotation centre of the spreading disc 203 is concentric with the motor axis of the spreading disc drive 207.

[0198] The spreading disc drive 207 may be controlled by the onboard controller 14, 15, 16 or by a payload controller 172.

[0199] The spreading disc 203 may comprise one or more radial guides 206. The radial guides 206 may facilitate long and predictable spreading distance for a givenrotational speed of the spreading disc. The radial guides 206 may be attached to the spreading disc 203 by mechanical means or by chemical means. Mechanical means may include bolts, screws, or snap-locks. Chemical means may include glue or weld onto the spreading disc 203. Non-limiting examples of radial guides 206 may be plates, screens, grooves in the material of the spreading disc 203 or protrusions of the material of the spreading disc 203.

[0200] The radial guides 206 may cause the spreading pattern 218 to be provided as arches expanding radially from a centre of the spreading disc 203. The arches may be comprised in a circle sector forming the spreading pattern 218.

[0201] A product supply 202 may be configured to feed product 201 onto the spreading disc 203. The product supply 202 may be a tank 170. The product supply 202 may be a tank integrated with the device 171. The product supply 202 may be an exchangeable product supply 202 configured to be releasably attached to the device 171. The product supply 202 may be a commercially available container for granulated product 201 which the device 171 is configured to receive.

[0202] Product 201 is fed from the product supply 202 through a controllable product aperture 209. The product aperture 209 is controllable in that it may control a feeding rate of product 201 from the product supply 202 to the spreading disc 203. Feeding rate is typically the amount of product 201 fed from the product supply 202 per unit of time.

[0203] The product aperture 209 may be a controllable opening, such as a hatch or gate. The controllable opening may be controlled by multiple hatches or gates. The size of the opening may be controlled by manual levers or by controllable actuators operably connected to the hatches or gates. In the case of multiple hatches or gates, the controllable opening may adjust the position of where product 201 is released onto the spreading disc 203.

[0204] The product aperture 209 may be a rotary metering device.

[0205] The product aperture 209 may be controlled by the onboard controller 14, 15, 16 or by a payload controller 172.

[0206] The product aperture 209 may be configured to release product 201 vertically above the spreading disc 203.

[0207] The product supply 202 may comprise a controllable opening actuator 210. The opening actuator 210 may be controllable in that it can adjust a position of where product 201 is fed from the product supply 202 onto the spreading disc 203.

[0208] The opening actuator 210 may control a flexible ending of the product supply 202, such as a hose or tube.

[0209] The opening actuator 210 may be a linear or rotary actuator. The opening actuator 210 may be electrically or hydraulically operated.The opening actuator 210 may be controlled by the onboard controller 14, 15, 16 or by a payload controller 172.

[0210] The tilt arrangement 215 may allow the spreading disc 203 to be adjusted. Specifically, the tilt arrangement 215 may adjust the spreading disc 203 such that an angle of a spreading disc rotation axis is changed in relation to the device 171.

[0211] Adjustments may be according to ground irregularities or undulations.

[0212] Preferably a rotation axis of the spreading disc 203 may be parallel to a normal of a plane which tangents the ground over which the device 171 currently travels.

[0213] By tilting the spreading disc 203 the spreading pattern 218 may be adapted to hilly conditions or field undulations without interfering with the traveling orientation of the device 171.

[0214] The tilt arrangement 215 may allow tilting in multiple directions. Especially, the tilt arrangement 215 may provide tilting of the spreading disc around two geometrical axes.

[0215] A lateral actuator 216 may control the lateral tilt of the spreading disc 203. A lateral tilt of the spreading disc 203 may form an asymmetrical spreading pattern 218 over a vertical plane comprising a working direction Dw. Put differently, a lateral tilt of the spreading disc may form an asymmetrical spreading pattern 218 from left to right of the device 171.

[0216] A lateral actuator 216 may be a rotary actuator, as shown in Fig. 3, configured to rotate the spreading disc 203 around a pivot axis Al. A lateral actuator 216 may be an electric or hydraulic actuator.

[0217] A longitudinal actuator 217 may control the longitudinal tilt of the spreading disc 203. A longitudinal tilt of the spreading disc 203 may form an asymmetrical spreading pattern 218 over a vertical plane perpendicular to a working direction Dw. Put differently, a lateral tilt of the spreading disc may form an asymmetrical spreading pattern 218 from back to front of the device 171.

[0218] A longitudinal actuator 217 may be a linear actuator, as shown in Fig. 3. A longitudinal actuator 217 may be an electric or a hydraulic actuator. A linear longitudinal actuator 217 may be configured to rotate the spreading disc 203 around a pivot axis A2. A longitudinal actuator 217 may be pivotably connected to the tilt arrangement at an axis A3. By changing length of a linear longitudinal actuator 217, tilting of the spreading disc 203 around axis A2 may be achieved.

[0219] In some exemplifying embodiments, the tilt arrangement 215 may be configured to support multiple components. In the exemplifying embodiment in Fig. 3 the tilt arrangement 215 is, beyond the spreading disc 203, supporting the spreading disc drive 207 and the detector 204. In an embodiment as shown in Fig. 3 the spreading disc drive 207 and the detector 204 may be tilted together with the spreading disc 203 when acted upon by one or more lateral actuator 216 and thelongitudinal actuator 217. One or more of the lateral actuator 216 and the longitudinal actuator 217 may, at least in one end, be connected to the spreading disc drive 207.

[0220] In other embodiments, the detector 204 may be supported by the device 171 such that the detector 204 is in an unchanged position in relation to the device 171 during a tilt of the tilt arrangement 215. Put differently, in such embodiments the spreading disc 203 may be tilted without the detection plane 205 being affected. In some embodiments it may be beneficial to keep the detection plane 205 in an unchanged orientation while tilting the spreading disc 203.

[0221] The device 171 may comprise a ground measurement sensor 213. A ground measurement sensor 213 may comprise multiple sensor units. A ground measurement sensor 213 may be a contactless sensor, such as radar, lidar or ultrasonic sensor. In some exemplifying embodiments a ground measurement sensor 213 may be comprised on the spreading disc side of a tilt arrangement 215. In such embodiments a ground measurement sensor 213 would follow the tilt of a spreading disc 203. In other exemplifying embodiments a ground measurement sensor 213 may be comprised on the device, or on the lateral actuator 216 as shown in Fig. 3.

[0222] A ground measurement sensor 213 may provide information about ground under the device 171. Information about the ground may be distance, contours, irregularities, hills or undulations of the ground.

[0223] A ground measurement sensor 213 may provide information to an onboard controller 14, 15, 16, to payload controller 172 or to a remote processing unit.

[0224] A controller may process the information.

[0225] In response to the processing of the information, a controller may provide a control signal to one or more of the lateral actuator 216 and the longitudinal actuator 217 realizing a tilt of the spreading disc 203. Preferably the tilt is such that the spreading disc 203 is kept parallel to the ground over which the device 171 is currently travelling.

[0226] The detector 204 is placed at a lower vertical level than the spreading disc 203, when in an operating state. A detection plane 205 provided close to the ground may be preferred since that may allow for an accurate reading of how the spreading pattern 218 will land on the ground.

[0227] The detection plane 205 is preferably provided above, and preferably vertically spaced from, the crop or ground to which the product is distributed. The detector 204 may comprise at least one sensor 214. The sensor 214 may be a sensor configured to transmit electromagnetic waves, or beams, and receive reflections from the transmitted electromagnetic waves or beams.A lidar sensor emits pulses of laser light and measures the time it takes for the light to reflect off objects and return to the sensor. This time-of-flight measurement is used by the detector to calculate the distance between the sensor and the object. The sensor typically consists of a laser source, a photodetector, and a timing system. The laser source emits short pulses of light, the photodetector captures the reflected light, and the timing system records the time interval between emission and detection.

[0228] The sensor 214 may be a lidar sensor, such as rotary lidar sensor, a hybrid lidar sensor, a solid-state lidar sensor or a flash lidar sensor. A hybrid lidar sensor typically uses movable mirrors to prisms to deflect laser beams.

[0229] The detector 204 may provide one or more laser beams. The laser beams may reflect on product granules 201 to provide a detectable point of intersection between a detection plane 205 and product granules 201. The reflection may be detectable by the detector 204. The detector 204 may be configured to derive information from the reflection about a distance and a direction between the detector 204 and the point of intersection.

[0230] The detector 204 is configured to provide a detection plane 205. The detection plane 205 may be provided as an array of laser beams with angular displacements between each other. The detection plane 205 may be scanned such that points of intersections between the detection plane 205 and the product granules 201 causes a by the detector 204 detectable reflection. By detecting multiple reflections from multiple granules, information about a spreading pattern 218 may be registered.

[0231] Distances and directions from the detector 204 to multiple reflections may be accumulated to provide information about a spreading pattern 218. The accumulation may be done by the detector 204 or by a processing unit in communicative connection with the detector 204.

[0232] The detector 204 may additionally be configured to detect obstacles 211. In particular, the detector 204 may be configured to detect obstacles 211 beyond where the product granules 201 intersect the detection plane 205.

[0233] The detector 204 may comprise a processing unit or be in connection with an external processing unit, such as the onboard controller 14, 15, 16 or the payload controller 172.

[0234] The detection plane 205 is provided by the detector 204. The detection plane 205 is provided as an array of laser beams originating in the sensor 214. The array of laser beams typically presents an angular displacement in relation to each other.

[0235] The detection plane 205 is typically in the shape of a circle sector. Preferably, such circle sector may coincide in shape and orientation with a maximum throwing sector of the disc 203.The detection plane 205 may be provided as a full circle.

[0236] A centre of the detection plane 205 may be the point where the radiuses of a circle sector that is the detection plane 205 meet. The centre of the detection plane 205 may be where the sensor 214 is arranged.

[0237] A centre of the detection plane 205 may be concentric with a rotation axis of the spreading disc 203.

[0238] Multiple detection planes 205 may be provided from multiple sensors 214 within the detector 204. Such multiple detection planes 205 may be provided at different vertical heights.

[0239] The detector 204 may comprise or be connected to a processing unit comprising a control system.

[0240] The control system may be configured to receive information about reflections between product granules 201 and the detection plane 205. The control system may accumulate points of intersection between the detection plane 205 and product granules 201 to register information about a spreading pattern 218.

[0241] The control system may be preprogrammed with a predetermined spreading pattern 219. The predetermined spreading pattern 219 may comprise geographic information about where product shall be spread by the device 171. It may also comprise information about how much product shall be spread to a specific area. The predetermined spreading pattern 219 may be transferred to the device 171 via wireless transfer, transfer by wire or from a memory device.

[0242] The control system may be configured to compare the predetermined spreading pattern 219 to the registered spreading pattern 218 to provide a delta between the two, further shown in Fig. 4b. The delta may be used for control system calculations for adaptation of the spreading pattern 218 to provide the predetermined spreading pattern 219.

[0243] The control system may further be in communicative connection to one or more actuators, such as the spreading disc drive 207, the product aperture 209, the opening actuator 210, the lateral actuator 216 or the longitudinal actuator 217. Through the connection the control system may control the one or more actuators to adapt a spreading parameter, such as the rotational speed of the spreading disc 205, the feeding rate of product 201 onto the spreading disc 205, the position where product 201 is being released onto the spreading disc 205 or the lateral or longitudinal tilt angle of the spreading disc 205. The adaptation of a spreading parameter may be such that the registered spreading pattern 218 provides the predetermined spreading pattern 219.

[0244] A control strategy may be implemented to provide a hierarchy for what spreading parameter to adapt under specific circumstances.The control system may control the one or more actuators in response to the measurements provided by the ground measurement sensor 213. The control system may, for instance, adjust an angle of the spreading disc 203 in response to a measurement from the ground measurement sensor. The response may be when the ground measurement sensor 213 provides information to the control system of hilly ground conditions.

[0245] The control system may further be configured to adapt a spreading parameter in response to an obstacle 211 detected by the detector 204. The response may be such that the spreading pattern 218 is adapted to not spread towards the detected obstacle 211.

[0246] The control system may further be in communicative connection to a steering control system of a vehicle comprising the device 171. In an exemplifying embodiment where the device 171 is arranged on an UAV 1, the control system may be configured to adapt a flight parameter in response to an obstacle 211 detected by the detector 204. A flight parameter may be a lateral, longitudinal or vertical change of direction of the UAV 1. Such flight parameter may be adapted by adjusting a flight actuator of the UAV 1, such as a propeller speed or propeller blade angle.

[0247] The control system may be in communicative connection with a collision avoidance system of the UAV 1. In particular, the detector 204 may detect obstacles 211 close to ground, such as wildlife or fences, and a collision avoidance system of the UAV 1 may detect obstacles 211 at a higher vertical level, such as buildings or power line poles. The control system may adjust a spreading parameter in response to an obstacle 211 detected by a collision avoidance system of the UAV 1.

[0248] In an exemplifying embodiment where the device 171 is arranged on a ground-based agricultural implement 400 the control system may be configured to adapt a steering parameter of a traction vehicle 500 carrying the device 171. Such steering parameter may be a steering angle of wheels of the traction vehicle 500.

[0249] The control system may be configured to adapt a steering parameter of a vehicle comprising the device 171 in response to the detected obstacle 211.

[0250] The control system may control the steering of a vehicle comprising the device 171 in response to the measurements from the ground measurement sensor 213. In particular, the control system may cause a UAV 1 comprising the device 171 to elevate to a predetermined altitude in response to a height measurement from the ground measurement sensor 213.

[0251] Referring to Figs. 4a-4b, an exemplifying embodiment of an UAV 1 comprising a device 171 is illustrated. Figs 4a-4b illustrates a top view of an UAV 1 comprising a device 171.As illustrated the device 171 creates a spreading pattern 218. The spreading pattern 218 is preferably symmetrical over a vertical plane comprising a working direction Dw. A width of the spreading pattern 218 may correspond to a rated working width of the device 171. The width of the spreading pattern 218 may correspond to a width greater than a rated working width if the device 171, taking account for overlaps when travelling in alternating passes back and forth over a ground area.

[0252] As illustrated in Fig. 4b, the spreading pattern 218 may deviate from a predetermined spreading pattern 219.

[0253] Such deviation may arise from a variety of factors, such as factors relating to the product, driving direction and wind direction.

[0254] The device 171 may be configured to adjust the spreading pattern 218 to provide the predetermined spreading pattern 219. The device 171 may be configured to inform of any delta between the spreading pattern 218 and the predetermined spreading pattern 219 to a user interface.

[0255] In the illustrated example the spreading pattern 218 is deviated 15 degrees from the predetermined spreading pattern 219.

[0256] Referring to Fig. 5, an exemplifying embodiment of a ground-based agricultural implement 400 comprising a device 171 is illustrated. The agricultural implement 400 comprises a frame 401 for connection to a traction vehicle 500. The traction vehicle 500 may be an agricultural towing vehicle, such as a tractor, a driverless agricultural towing vehicle or an agricultural gantry vehicle.

[0257] A spreading pattern 218 may be provided by the device 171. The spreading pattern 218 may be generally horizontal. The spreading pattern 218 may be provided rearwardly of the traction vehicle 500, with reference to a working direction Dw. Alternatively, the spreader device may be positioned to provide the spreading pattern forwardly of the spreader device, in particular when the spreader device is mounted at a front end of the traction vehicle.

[0258] The frame 401 may comprise a linkage 402 for being mounted to a traction vehicle 500. The agricultural implement 400 may be supported solely by the traction vehicle 500, without ground supports. The linkage 402 may be configured for connection to a 3-point hitch of an agricultural tractor. The agricultural implement 400 may be arranged in front of the traction vehicle 500, with reference to a working direction Dw.

[0259] Fig. 6 illustrates an alternative embodiment of a ground-based agricultural implement 400 comprising a device 171, where the frame 401 comprises a connector 403 for being towed by a traction vehicle 500. The connector 403 may be configured to attach to a 3-point hitch of an agricultural tractor, a 2-point hitch of an agricultural tractor or a trailer or hook coupling of an agricultural tractor. A 2-pointhitch may be the 2 lowermost connection points of a 3-point hitch. The agricultural implement 400 further comprises ground supports 404, which may be wheels or tracks. The ground supports 404 may be an even number of ground supports 404, symmetrically arranged to the frame 401 over a vertical plane comprising a working direction Dw. The ground supports 404 may be rotatably connected to the agricultural implement 400. The ground supports 404 may vertically support part of a weight of the agricultural implement 400. The weight not supported by the ground supports 404 may be supported by the traction vehicle 500 at the connector 403.

[0260] Referring to Fig. 7, a schematical illustration of a method of detection a spreading pattern 218 of granular product 201 from a device 171 is shown. The granular product 201 may be agricultural product, such as seeds or fertilizer.

[0261] The method comprises feeding SI product 201 from a product supply 202 of the device 171 onto a spreading disc 203. A feeding rate may be controlled through a product aperture 209. A feeding position may be controlled by an opening actuator 210.

[0262] The method further comprises causing S2 the spreading disc 203 to rotate. The rotation may be caused by a spreading disc drive 207, operably coupled to the spreading disc 203. The feeding of product 201 onto the spreading disc 203 while the spreading disc 203 is caused to rotate causes the product 201 to be thrown from the spreading disc 203 in a generally radial direction to form a spreading pattern 218. The spreading pattern is typically formed as a circle sector with the spreading disc 203 in a centre of the circle sector.

[0263] The throw may be improved by radial guides 206 providing longer throw and predictable trajectory. The radial guides 206 may cause the spreading pattern 218 to be provided as arches expanding radially from a centre of the spreading disc 203. The arches may be comprised in a circle sector forming the spreading pattern 218.

[0264] The method further comprises providing S3 a detection plane 205 by use of a detector 204. The detection plane 205 may be provided in parallel to the spreading pattern 218. The spreading pattern 218 and the detection plane 205 may be provided in a generally horizontal plane. The detection plane 205 may be parallel to a rotation plane of the spreading disc 205.

[0265] The detection plane 205 may be provided as an array of laser beams transmitted from a sensor 214. The array may be formed as a circle sector, where the sensor 214 is provided in the centre of the circle sector. The array may be provided from one sensor 214 which is caused to rotate to cause an angular displacement between the transmitted beams. The array may be provided from multiple sensors 214 transmitting laser beams with angular displacement between each other.The method further comprises detecting 54, by use of a detector 204, points of intersection between the detection plane 205 and product granules 201. Points of intersection may be detected by receiving a reflection of a laser beam transmitted from the detector 204 and reflected from a product granule 201. The reflection may be detectable by the detector 204. The detector 204 may from the reflection derive information of a distance and a direction (or angle) between the detector 204 and the point of intersection. Information from multiple distances to multiple points of intersections may provide to the detector 204, or a connected processing unit, information about a spreading pattern 218. The multiple distances, and geometrical directions about in what direction from the detector 204 that distance was measured, may be accumulated to provide information about the spreading pattern 218.

[0266] An optional subsequential step is comparing 55 the detected spreading pattern 218 to a predetermined spreading pattern 219. The predetermined spreading pattern 219 may be preloaded in a control unit in communicative connection to the detector 204. The comparison between the spreading pattern 218 and the predetermined spreading pattern 219 may provide a delta between the two. The delta may provide a metric on how well the spreading pattern 218 provides the predetermined spreading pattern 219.

[0267] The delta may optionally be used for subsequentially adjusting 56 the spreading pattern 218 to provide the predetermined spreading pattern 219. The adjustment may be done by controlling one or more spreading pattern actuators, such as the spreading disc drive 207, the product aperture 209, the opening actuator 210, a lateral actuator 216 or a longitudinal actuator 217. The spreading pattern actuators may be controlled to adjust one or more spreading parameters, such as a rotational speed of the spreading disc 205, a feeding rate of product 201 onto the spreading disc 205, a position where product 201 is being released onto the spreading disc 205 or a lateral or longitudinal tilt angle of the spreading disc 205. A control strategy may be implemented to provide a hierarchy for what spreading parameter to adapt under specific circumstances.

[0268] The device 171 may optionally be carried by an unmanned aerial vehicle 1, "UAV". The method may comprise the optional initiating step causing X0 the UAV 1 to fly over ground onto which the granular product 201 is to be spread. The UAV 1 may be manually controlled by a remote controller. The UAV 1 may be automatically controlled by a control system. The UAV 1 may be controlled to fly back and forth over an area of ground to which product 201 is to be spread.

[0269] The device 171 may optionally be arranged on a frame 401 of an agricultural implement 400. The method may comprise the optional initiating step connecting Y0 the agricultural implement 400 to a traction vehicle 500. The traction vehicle 500may be an agricultural towing vehicle, such as a tractor, driverless agricultural towing vehicle or agricultural gantry vehicle. The connection may be such that the agricultural implement 400 is mounted to, or towed by, the traction vehicle 500.

[0270] The agricultural implement 400 may be mounted to a traction vehicle 500 via a 3-point hitch coupling. The agricultural implement 400 may be vertically supported only by the traction vehicle 500.

[0271] The agricultural implement 400 may alternatively be configured to be towed by a traction vehicle 500. In such alternative the agricultural implement 400 may be connected to a traction vehicle 500 via a hitch coupling, a 3-point hitch coupling or 2-point hitch coupling. The agricultural implement 400 may further comprise ground supports 404, such as wheels or tracks, arranged to vertically support part of the agricultural implement 400.

[0272] The method may further comprise the optional step causing Y1 the traction vehicle 500 to drive over the ground onto which the product 201 is to be spread. The traction vehicle 500 may be manually operated by a driver, remotely operated by an operator, or caused to drive by an automatic control system. The traction vehicle 500 may be caused to drive back and forth over an area of ground onto which the product 201 is to be spread, to effectively cover a whole area with product 201.

[0273] Referring to Fig. 8, there is illustrated an embodiment in which the detection plane 205 is non-parallel to a disc plane.

[0274] Depending on the speed with which granules are thrown off the disc 203, a maximum detection range of the sensor may be exceeded. Hence, it may be advantageous to arrange the sensor plane 205 at an acute angle relative to the disc plane. The angle between the sensor plane 205 and the disc plane may be on the order of about 20-50 degs, such as about 20-25 degs, about 25-30 degs, about 30-35 degs, about 35-40 degs, about 40-45 degs or about 45-50 degs.

[0275] Consequently, an effective measuring distance may be on the order of about 20-100 cm, in particular about 20-30 cm, about 30-40 cm, about 40-50 cm, about 50-60 cm, about 60-70 cm, about 70-80 cm, about 80-90 cm or about 90-100 cm.

[0276] Referring to Fig. 9, a sensor 204 in the form of a lidar may be used, which is configured with a rotating mirror that can provide 300-1000 beams LB1-LB7 per rotation.

[0277] Referring to Fig. 10, there is illustrated the beams from the sensor 204 provided as a plane 205.

[0278] Referring to figs lla-llb, there is illustrated a spreader device 171 having a spreader unit support 1712 comprising a proximal part 17121 and a distal part 17122, which are connected by a release device 17123, configured for causing thedistal part 17122 to break free form the proximal part 17121 in the event of a collision, e.g. by the spreader unit 1711, with an obstacle.

[0279] The proximal part 17124 may attach to a payload body 17124, or to the UAV 1.

[0280] The release device 17123 may be configured in a variety of ways:

[0281] In a first alternative, the release device may be configured as a weakening or rupture zone provided in a duct or beam forming the spreader unit support 1712.

[0282] In a second alternative, the release device 17123 may be configured as a replaceable joint, configured for joining two pieces forming the proximal and distal portions, respectively, of the spreader unit support 1712.

[0283] Such replaceable joint may be provided from a brittle material, and / or by means of a weakening or rupture zone.

[0284] In a third alternative, the release device 17123 as a pair of connectors, which are releasably held together.

[0285] For example, such connectors may be held together by a magnetic force, such as by one or more magnets and / or magnetizable materials. Such magnets may be permanent magnets or electromagnets.

[0286] As another example, such connectors may be held together by one or more breakable devices, such as break pins, or the like.

[0287] As another example, such connectors may be held together by adhesion, e.g. by one or more adhesive devices, such as double-sided adhesive tape, or the like.

[0288] As yet another example, such connectors may be held together by one or more biased locking members.

[0289] Referring to fig. 11c, the release device 17123 may comprise a pair of connector bodies 171231, 171232, which may be mounted to, or provided in one piece with, a respective one of the proximal part 17121 and the distal part 17122 of the spreader unit support 1712.

[0290] An alignment device 171233, 171234 may be provided, which may be designed as a protrusion (as illustrated at 171233) and a corresponding recess (as illustrated at 171234), which align the connector bodies 171231, 171232 in at least one direction transversely of the longitudinal direction of the spreader unit support 1712.

[0291] In the case of magnets, magnets and / or magnetizable material may be arranged at corresponding positions in the connector bodies 171231, 171232, such that the connector bodies 171231, 171232 are prevented from separating.

[0292] In the case of adhesion, adhesive material may be provided on surfaces of the connector bodies 171231, 171232, which face each other.

[0293] It is also possible to provide mechanically interlocking devices on the connector bodies 171231, 171232, which may be configured to break or which maybe spring-loaded (biased) and configured to release when subjected to a sufficient force.

[0294] Referring to figs 12a-12c, there is illustrated another embodiment of a release device 17123, which also uses magnets for holding the connector bodies 171231, 171232 together. The connector bodies may comprise one or more pins on one of the connector bodies 171231, 171232 and one or more corresponding hooks on the other one of the connector bodies 171231, 171232, whereby the connector bodies 171231, 171232 may be configured to release only when subjected to a collision force in a particular direction. In the illustrated example, the connector bodies 171231, 171232 will release only when subjected to a collision force having a sufficient force component in a direction opposite the working direction Dw.

[0295] A locking mechanism 171235 may be provided, which may be configured to block the release mechanism 17123 depending on whether the spreader unit support 1712 is in a working position or in a retracted, upper, position.

[0296] For example, with the position of the spreader unit support 1712 being controlled by a wire 171236 connected to an actuator at the UAV 1, which may include a reel, onto which the wire may be selectively wound, the locking mechanism 171235 may be configured to lock or unlock the release device 17123 depending on an angle Aw at which the wire 171236 extends relative to the locking mechanism 171235.

[0297] Hence, the release device 17123 may be disabled when the spreader unit support 1712 is in an upper, retracted, position, such as when the UAV 1 is to land.

[0298] Moreover, the release device 17123 may be enabled only when the spreader unit support 1712 is in a lower position, such as when the spreader unit is ready for operation.

[0299] The release device 17123 may be designed to define a joint plane Pj, i.e. a plane at which the connectors meet. Such joint plane Pj may be provided at a joint angle Aj relative to a longitudinal direction of the spreader unit support 1712.

[0300] Preferably, such joint angle Aj should be non-perpendicular. It may be preferable if the joint angle Aj is an acute angle and in particular an angle that is no more than 60 degs, preferably no more than 45 degs or no more than 30 degs.

[0301] The release device 17123 may be provided closer to the payload body 17124 than to the spreader device. In particular, the release device may be provided at a distance from the payload body 17124 corresponding to about 1-50 % of a spreader unit support 1712 length, preferably about 1-40 %, about 1-30 %, about 1-20 % or about 1-10 %.

[0302] It is possible to provide a safety device, configured to prevent the release device 17123 from being triggered unnecessarily, e.g. when the UAV 1 is at a landing site or an airbase. Such safety device may be provided by an electronicallycontrollable locking function, which prevents separation of the connectors. Such locking function may comprise a locking pin, which may be movable between a locking position in order to prevent separation and a release position in order to allow for separation.

[0303] It is possible to provide a catch-line, configured to catch the distal part 17122 if broken away, such that it will not be necessary for an operator to go and pick it up out in a field.

[0304] The spreader device 1711 may be a spreader device for spreading a solid product, such as a granular or powdery product, or a spreader device for spreading a liquid product. The later spreader device may comprise a spreader beam extending transversely of the spreader unit support 1712 and / or one or more sprayer devices.

Claims

32CLAIMS1. A method for detecting a spreading pattern from a distribution device (171) distributing granular product (201) to an area, comprising:- causing a spreading disc (203) of the device (171) to rotate in a plane generally parallel to the ground over which the device (171) travels,- feeding product (201) from a product supply (202) to the spreading disc (203) such that the product (201) is thrown by the rotating spreading disc (203) to form a spreading pattern (218),- operating a detector (204) comprising a sensor, in particular a lidar sensor, to provide a detection plane (205),wherein said detector (204) is arranged vertically below the spreading disc (203), andwherein said detection plane (205) is angled, preferably upwardly from the detector (204), towards an intersection between the detection plane (205) and the spreading pattern (218),- detecting the spreading pattern (218) by registering a distance between the detector (204) and the intersection.

2. The method as claimed in claim 1, wherein the granular product (201) is agricultural granular product, such as seeds, fertilizer, pesticide, herbicide or fungicide.

3. The method as claimed in claim 1 or 2, wherein providing a detection plane comprises:transmitting, from the detector (204), a first laser beam (LB1), transmitting, from the detector (204), a second laser beam (LB2), wherein the second laser beam (LB2) is separated from the first laser beam (LB1) by an angle (VI).

4. The method as claimed in claim 3, wherein registering a distance between the detector (204) and the intersection comprises:receiving a reflection of the first laser beam (LB1), reflecting off one or more granules of the spreading pattern (218),calculating a distance to the reflecting granule(s) by time-of-flight calculation of the first laser beam (LB1),receiving a reflection of the second laser beam (LB2), reflecting off one or more granules of the spreading pattern (218),calculating a distance to the reflecting granule(s) by time-of-flight calculation33of the second laser beam (LB2).

5. The method as claims in any of the preceding claims, further comprising:operating the device (171) to travel back-and-forth over an agricultural area in non-overlapping paths, while distributing granulated product (201) and detecting the spreading pattern (218).

6. The method as claimed in claim 5, wherein operating the device (171) to travel comprises:mounting the device (171) to an unmanned aerial vehicle (1), "UAV", causing the UAV (1) to fly over the agricultural area.

7. A device (171) for spreading a granular product (201) to ground over which the device (171) travels, the device (171) comprising:a spreading disc (203) configured to rotate in a plane generally parallel to the ground over which the device (171) travels,a product supply (202) configured to feed product (201) onto the spreading disc (203), while the spreading disc (203) is caused to rotate, to form a spreading pattern (218) of granules,a detector (204) including a lidar sensor, configured to provide a detection plane (205) comprising angularly separated laser beams (LB1, LB2, LB3, LB4, LB5, LB6, LB7),wherein the detector (204) is arranged vertically below the spreading disc (203), andwherein the detection plane (205) is angled upwardly from a center of the detector (204) to an intersection between the detection plane (205) and the spreading pattern (218),wherein the detector (204) is further configured to detect points of intersections between the detection plane (205) and product granules (201) within the spreading pattern (218).

8. An unmanned aerial vehicle (1), "UAV", comprising the device (171) according to claim 7,wherein the UAV (1) comprises:a frame,one or more rotatable rotors,and wherein the device (171) is mounted to the frame at a lowermostportion thereof.

9. An UAV (1) according to claim 9, wherein the UAV (1) further comprises an elongated spreader unit support (1712),wherein a proximal portion of the spreader unit support (1712) is connected to the frame of the UAV (1), andwherein the device (171) is mounted to a distal portion of the spreader unit support (1712), such that the device (171) is supported outside a footprint of the UAV, as seen in a horizontal plane.

10. A device (171) for spreading at least one granular product (201) to ground over which the device travels, the device (171) comprising:a spreading disc (203) configured to rotate in a generally horizontal plane, a product supply (202) configured to feed product (201) onto the spreading disc (203), while the spreading disc (203) is caused to rotate, to form a spreading pattern (218) of granules,a detector (204), configured to provide a detection plane (205) of electromagnetic radiation, which is approximately parallel with and below the horizontal plane,wherein the detector (204) is configured to detect points of intersections between the detection plane (205) and product granules (201).

11. The device (171) according to claim 10, wherein the detector (204) is supported by the device (171) via a tilt arrangement (215),and wherein the tilt arrangement (215) is configured to allow angular displacement of the detector (204) around at least one geometric axis.

12. The device (171) according to claim 10 or 11, wherein the detector (204) is vertically spaced from the spreading disc (203), such that the detector (204) is provided closer to the ground than the spreading disc (203) in a working mode.

13. The device (171) according to any one of claims 10-12, wherein a centre of the detection plane (205) is arranged vertically under the spreading disc (205).

14. The device (171) according to any one of claims 10-13, wherein the detection plane (205) is provided by at least one laser beam transmitted from the detector (204),and wherein the detector (204) comprises a receiver configured to receive reflections of the at least one laser beam.

15. The device (171) according to any one of claims 10-14, wherein the detector (204) is further configured to detect obstacles (211) intersecting the detection plane (205).

16. The device (171) according to any one of claims 10-15, wherein the detector (204) comprises, or is connected to, a processing unit configured to accumulate points of intersections to register the spreading pattern (218) of granules.

17. The device (171) according to claim 16, wherein the detector (204) comprises, or is connected to, a processing unit further configured to compare the registered spreading pattern (218) to a predetermined spreading pattern (219).

18. The device (171) according to claim 17, wherein the detector (204) is further configured to control at least one spreading parameter actuator to adjust the spreading pattern (218) to provide the predetermined spreading pattern (219).

19. The device (171) according to any of the claims 15 to 18, wherein the detector (204) is further configured to provide information of a detected obstacle (211) to a spreading control unit,and wherein the spreading control unit is configured to adjust a spreading parameter actuator to adapt the spreading pattern (218) in accordance with the detected obstacle (211).

20. The device (171) according to any of the claims 15 to 19, wherein the detector (204) is further configured to provide information of a detected obstacle (211) to an onboard controller (14, 15, 16),and wherein the onboard controller (14, 15, 16) is configured to inform about, or adjust a travel route of the device (171) to avoid, the detected obstacle (211).

21. The device (171) according to any one of claims 10-20, wherein the spreading disc is caused to rotate by a spreading disc drive (207) operably coupled to the spreading disc (203) to provide rotational movement.3622. The device (171) according to any one of claims 10-121, wherein the spreading disc (203) is arranged on the tilt arrangement (215).

23. The device (171) according to any one of claims 11-22, wherein the tilt arrangement (215) comprises a lateral actuator (216) configured to tilt about a first pivot axis (Al) which is parallel to a working direction (Dw).

24. The device (171) according to any one of claims 11-23, wherein the tilt arrangement (215) comprises a longitudinal actuator (217) configured to tilt around a second pivot axis (A2) which is perpendicular to a working direction (Dw).

25. The device (171) according to any one of claims 11-24, wherein the tilt arrangement (215) further comprises a ground measurement sensor (213), wherein the ground measurement sensor (213) is configured to provide information of the ground surface over which the device (171) currently travels.

26. The device (171) according to claim 25, wherein the tilt arrangement (215) is configured to control one or more of the lateral actuator (216) and the longitudinal actuator (217) in response to ground measurements provided by the ground measurement sensor (213).

27. The device (171) according to any one of claims 10-26, wherein the spreading disc (203) presents a concave shape.

28. The device (171) according to any one of claims 10-27, wherein the spreading disc (203) comprises radial guides (206), configured to guide the product (201) approximately radially outwardly from the disc.

29. The device (171) according to any one of claims 10-28, wherein the product (201) is fed from the product supply (202) onto the spreading disc (203) through a controllable product aperture (209).

30. The device (171) according to claim 29, wherein the product aperture (209) is controllably movable above the spreading disc (203) by an opening actuator (210), such that a feeding position of product (201) from the product supply (202) onto the spreading disc (203) may be controlled.3731. An unmanned aerial vehicle (1), "UAV", comprising a device (171) according to any of the claims 1 to 30.

32. The UAV (1) according to claim 31, wherein the device (171) is supported by a spreading unit support (1712) which presents an elongated extension, wherein the spreading disc (203) is carried at a distal portion of the spreading unit support (1712),and wherein a proximal portion of the spreading unit support (1712) is connected to a frame (11),such that the spreading unit support (1712) provides the spreading disc (203) outside, as seen in a horizontal direction, of a downwash area.

33. The UAV (1) according to claim 32, wherein the spreading unit support (1712) comprises a product feed along its elongated extension.

34. The UAV (1) according to any of the claims 31 to 33, wherein the device (171) comprises a single spreading disc (203).

35. An agricultural implement (400) comprising:a frame (401), anda device (171), according to any of the claims 10-30, connected to the frame (401).

36. An agricultural implement (400) according to claim 25, wherein the frame (401) comprises a linkage (402) for being mounted to a traction vehicle (500).

37. An agricultural implement (400) according to claim 36, wherein the frame comprises a connector (403), for being towed by a traction vehicle (500), and one or more ground supports (404).

38. A method of detecting a spreading pattern (218) of granular product (201) spread from a device (171),wherein the device (171) comprises:a spreading disc (203),a product supply (202), anda detector (204) configured to provide a detection plane (205) of electromagnetic radiation below a generally horizontal rotation plane of the spreading disc,wherein the method comprises:38- feeding (SI) product (201) from the product supply (202) onto the spreading disc (203),- causing (S2) the spreading disc (203) to rotate, in an approximately horizontal plane, to form a spreading pattern (218) of granules,- providing (S3), by the detector (204), the detection plane (205),- detecting (S4), by the detector (204), points of intersections between the detection plane (205) and product granules (201).

39. The method according to claim 38, wherein detecting (S4) points of intersections comprises:- accumulating data of a plurality of points of intersection to form the spreading pattern (218).

40. The method according to claim 38 or 39, further comprising the subsequential steps:- comparing (S5) the detected spreading pattern (218) to a predetermined spreading pattern (219), and- adjusting (56) the spreading pattern (218) to provide the predetermined spreading pattern (219) by controlling one or more spreading parameter actuators.

41. The method according to any of the claims 38 to 40, wherein the spreading disc (203) is caused to rotate by a spreading disc drive (207) operably coupled to the spreading disc (203) to provide rotational movement.

42. The method according to any of the claims 38 to 41, wherein the detection plane (205) is approximately parallel to a rotation plane of the spreading disc (203).

43. The method according to any of the claims 38 to 42, wherein the detection plane (205) is provided by at least one laser beam transmitted by the detector (204),and wherein reflected light from product granules is received by the detector (204).

44. The method according to any of the claims 38 to 43, wherein the device (171) is carried by an unmanned aerial vehicle (1), "UAV",and wherein an initiating step comprises:- causing (X0) the UAV (1) to fly over ground to which the granular39product (201) is to be spread.

45. The method according to any of the claims 38 to 44, wherein the device (171) is arranged on a frame (401) of an agricultural implement (400) which is configured to be coupled to a traction vehicle (500),and wherein initiating steps comprises:- connecting (Y0) the agricultural implement (400) to a traction vehicle (500), - causing (Yl) the traction vehicle (500) to drive over ground onto which the product (201) is to be spread.

46. The method according to claim 45, wherein the frame (401) comprises a linkage (402) for being mounted to an agricultural tractor (500).

47. The method according to claim 46, wherein the frame (401) comprises a connector (403), for being towed by an agricultural tractor (500), and one or more ground supports (404).

48. The method according to any of the claims 38 to 47, wherein the granular product (201) is agricultural product.

49. The method according to claim 48, wherein the granular product (201) is fertilizer or seeds.

50. A spreader unit for use in an unmanned aerial vehicle ("UAV") for spreading an agricultural product to an area over which the UAV travels, the spreader unit comprising:a product tank,a spreader device, configured for spreading the product, anda spreader unit support, configured to extend between the product tank and the spreader device,characterized in thatthe spreader unit support comprises a release device (17123), configured to allow for a distal portion of the spreader unit support to separate from a proximal portion of the spreader unit support, in particular upon a collision between the spreader device and an obstacle.

51. The spreader unit as claimed in claim 50, wherein the release device (17123) is provided closer to the product tank than to the spreader unit.4052. The spreader unit as claimed in claim 50 or 51, wherein the release device (17123) comprises a pair of connectors, which are releasably held together by at least one of a rupture device, a spring-loaded device, magnetic force device and an adhesive device.

53. The spreader unit as claimed in any one of claims 50-52, wherein the release device provides a joint plane (Pj), which provides a joint angle (Aj) relative to a longitudinal direction of the spreader unit support (1712), said joint angle (Aj) providing an acute angle, and in particular an angle that is no more than 60 degs, preferably no more than 45 degs or no more than 30 degs.

54. The spreader unit as claimed in any one of claims 50-53, further comprising a locking mechanism (171235) configured for selectively preventing separation of the distal portion of the spreader unit support from the proximal portion of the spreader unit support.

55. The spreader unit as claimed in claim 54, wherein the locking mechanism (171235) is configured to prevent or allow said separation in dependence of an orientation of the spreader unit support (1712).

56. An unmanned aerial vehicle comprising a spreader unit as claimed in any one of claims 50-55.

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