Autonomous agricultural vehicle comprising proximity sensor assembly with an air mover for removing and / or repelling movable debris

Abstract

A mobile autonomous agricultural system comprises: a powered mobile unit for carrying agricultural equipment, and configured to move along rows of crops; a controller configured to control the travel of the mobile unit; and at least one proximity sensor assembly. The at least one proximity sensor assembly comprises: a proximity sensor configured to detect the presence of an object in the vicinity of the mobile autonomous agricultural system; and an air mover configured to blow air into and / or around a field of view of the proximity sensor.

Description

[0001] PROXIMITY SENSOR ASSEMBLY

[0002] Field

[0003] The present disclosure concerns proximity sensor assemblies, mobile autonomous agricultural systems comprising proximity sensor assemblies, and methods of operating mobile autonomous agricultural systems comprising proximity sensor assemblies.

[0004] Background

[0005] Many agricultural tasks to improve yield and quality of crops, or to harvest crops, require time-consuming manual labour. However, many of the tasks required are repetitive and may therefore be suitable for help by autonomous machinery. Such autonomous machinery would typically be required to autonomously move around and between crops, and therefore presents a safety risk to people working in or around the crops or other users of the machinery.

[0006] Summary of invention

[0007] According to a first aspect, there is provided a mobile autonomous agricultural system comprising: a powered mobile unit for carrying agricultural equipment, and configured to move along rows of crops; a controller configured to control the travel of the mobile unit; and at least one proximity sensor assembly comprising: a proximity sensor configured to detect the presence of an object in the vicinity of the mobile autonomous agricultural system (for example, in the vicinity of the mobile unit); and an air mover configured to blow air into and / or around a field of view of the proximity sensor.

[0008] The proximity sensor may be any suitable type of proximity sensor operable to detect the presence of an object in the vicinity of the mobile autonomous agricultural system (for example, in the vicinity of the mobile unit).

[0009] It will be appreciated that a proximity sensor typically has a field of view. The field of view defines the region within which the proximity sensor is operable to detect the presence of an object. The field of view of a proximity sensor may be substantially planar. The field of view may be characterised by the solid angle through which theproximity sensor is operable to detect incoming signals (e.g. electromagnetic radiation, for example, light reflected from an object in the field of view), as measured at the proximity sensor. The proximity sensor in the present case may have a field of view characterised by a solid angle of no less than about 90°, for example, no less than about 120°, or no less than about 150°. The proximity sensor may have a field of view characterised by a solid angle of no more than about 210°, for example, no more than about 180°, or no more than about 150°.

[0010] The proximity sensor may be an optical proximity sensor. An optical proximity sensor may comprise a light emitting component which emits outgoing light and a light sensing component which senses incoming light. For example, the optical proximity sensor may be configured to emit light into the field of view (for example, within a particular wavelength range) and to detect light (for example, within the same wavelength range) reflected back towards the optical proximity sensor by an object present within the field of view.

[0011] The proximity sensor may be a laser scanner, for example, a safety laser scanner. The laser scanner (e.g. the safety laser scanner) may be configured to emit laser light within the field of view and to detect laser light reflected back towards the optical proximity sensor by an object present within the field of view. The laser scanner may be configured to emit the laser light within a plane. The plane within which the laser scanner is configured to emit laser light may define the field of view of the laser scanner. The laser scanner may emit a beam of laser light which is swept or rastered across the field of view (for example, using a rotating mirror). The beam of laser light may be continuous or pulsed.

[0012] The proximity sensor may be operable to detect the presence of an object when the object is within a threshold distance from the mobile unit.

[0013] The vicinity of the mobile autonomous agricultural system (for example, the vicinity of the mobile unit) may be defined by a distance of up to no more than about 3 m from the mobile unit, for example, no more than about 2 m from the mobile unit, or no more than about 1 m from the mobile unit.Accordingly, the proximity sensor may be configured to detect the presence of an object located a distance of up to about 3 m from the mobile unit, for example, up to about 2 m from the mobile unit, or up to about 1 m from the mobile unit.

[0014] The air mover may be configured to blow air into the field of view. That is to say, the air mover may cause movement of air within the plane of the field of view. Additionally or alternatively, the air mover may be configured to blow air around the field of view. That is to say, the air mover may cause movement of air on one or both sides of the field of view.

[0015] Blowing air into and / or around the field of view of the proximity sensor may remove and / or repel movable debris from the field of view. Such movable debris, if present within the field of view, may be sensed by the proximity sensor and provide an erroneous indication that an object of concern (for example, a human) is within the vicinity of the system.

[0016] The air mover may therefore be configured to blow air into and / or around the field of view of the proximity sensor to remove and / or repel movable debris from the field of view.

[0017] The movable debris may be made up of one or more small items of movable debris. The small items of debris may have a maximum dimension (e.g. length) of no more than about 5 cm, for example, no more than about 4 cm, or no more than about 3 cm, or no more than about 2 cm, or no more than about 1 cm.

[0018] The movable debris may include one or more animals, for example, one or more small animals, such as one or more arthropods, for example, one or more insects (e.g. flying insects) or spiders. It has been found that flying insects can be attracted to mobile autonomous agricultural systems (for example, they may be attracted to the lights of the systems at night) and spiders have been found to climb on and / or build webs on such systems.

[0019] The air mover may be configured to blow air into and / or around the field of view such that a velocity of the flow of air is sufficient to remove and / or repel arthropods, for example, one or more insects (e.g. flying insects) or spiders from the field of view, for example, within a distance of no less than about 10 cm, for example, no less than about 15 cm, from the proximity sensor.The air mover may be configured to blow air into and / or around the field of view such that a velocity of a flow of air at a point within the field of view at a distance of 16 cm from the proximity sensor is at least about 0.5 m / s. The velocity of the flow of air at a point within the field of view may be measured using a wind anemometer, as described hereinbelow in more detail. The velocity may be the velocity of the flow of air as measured in a radially outwards direction within the field of view (as defined relative to the location of the proximity sensor). The point at which the velocity is measured may be directly in front of the proximity sensor (i.e. located on a radial axis extending from the proximity sensor in the (i.e. angular) centre of the field of view). An air velocity of at least about 0.5 m / s may be sufficient to remove and / or repel movable debris (in particular, small animals such as insects or spiders) from the field of view.

[0020] The air mover may be configured to blow air into and / or around the field of view such that the velocity of a flow of air at the point within the field of view at the distance of 16 cm from the proximity sensor is at least about 1.0 m / s, or at least about 1.5 m / s, or at least about 2.0 m / s.

[0021] The air mover may be any suitable type of device operable to generate the flow of air. The air mover may be a fan. For example, the air mover may be an axial-flow fan, a centrifugal fan, a crossflow fan or a bladeless fan.

[0022] The at least one proximity sensor assembly may comprise an air filter configured to filter air entering and / or exiting the air mover. By filtering air entering and / or exiting the air mover, the amount of particulate matter (e.g. dust) to which the proximity sensor is exposed may be reduced, thus potentially reducing damage to the proximity sensor by such particulate matter. The air filter may comprise a foam material configured to trap particulate matter (e.g. dust).

[0023] The at least one proximity sensor assembly may comprise a body. The body may define a duct having an open aperture. The body and the proximity sensor may be positioned relative to one another such that the field of view of the proximity sensor extends through the duct and out through the open aperture. The air mover may be configured to blow air into and through the duct and out of the open aperture.The body may form part of, or may be, a housing for the at least one proximity sensor. The housing may house the proximity sensor. The housing may be mounted on the mobile unit.

[0024] The duct may be configured to direct air flow out of the open aperture into and / or around the field of view of the proximity sensor outside the body (i.e. outside the at least one proximity sensor).

[0025] The at least one proximity sensor assembly may comprise one or more vanes configured to direct air flow from the air mover into and / or through the duct. The one or more vanes may be located within a conduit which provides an air flow path between the air mover and the duct.

[0026] The at least one proximity sensor assembly may comprise a single air mover. Alternatively, the at least one proximity sensor assembly may comprise two or more air movers (i.e. a plurality of air movers).

[0027] The at least one proximity sensor assembly may comprise two air movers positioned on either side of the proximity sensor and configured to blow air into and / or around the field of view of the proximity sensor.

[0028] The at least one proximity sensor assembly may comprise a corresponding conduit for each air mover, wherein each conduit provides an air flow path between the corresponding air mover and the duct.

[0029] The radial distance between the open aperture and the proximity sensor may be no less than about 10 mm, for example, no less than about 20 mm, or no less than about 30 mm, or no less than about 40 mm, or no less than about 50 mm. The radial distance between the open aperture and the proximity sensor may be no more than about 200 mm, for example, no more than about 150 mm, or no more than about 100 mm, or no more than about 80 mm. The radial distance between the open aperture and the proximity sensor may correspond to the radial distance D as discussed hereinbelow in more detail.

[0030] The open aperture may have a width of no less than about 3 mm, for example, no less than about 5 mm, or no less than about 7 mm. The open aperture may have a width ofno more than about 50 mm, for example, no more than about 40 mm, or no more than about 30 mm, or no more than about 20 mm, or no more than about 15 mm. The width of the open aperture may be the perpendicular spacing distance between portions of the body on either side of the open aperture at an outermost edge. The width of the open aperture may correspond to the spacing S as discussed hereinbelow in more detail.

[0031] The at least one proximity sensor assembly may comprise a shade configured to shade the proximity sensor from exposure to ambient light, for example, sunlight.

[0032] The shade may be positioned outside a field of view of the proximity sensor. The shade may be positioned between the field of view of the proximity sensor and the source of ambient light. For example, the shade may be positioned between the field of view of the proximity sensor and the sun, or between the field of view of the proximity sensor and a reflective surface (for example, a puddle of water), which reflects sunlight.

[0033] The shade may be configured to block ambient light from reaching a sensing component of the proximity sensor. For example, the proximity sensor may be an optical proximity sensor and the shade may be configured to block ambient light from reaching an optical sensing component of the optical proximity sensor.

[0034] The body of the at least one proximity sensor assembly may comprise a wall which functions as the shade.

[0035] The body and the proximity sensor may be positioned relative to one another such that the wall is positioned outside the field of view of the proximity sensor and extends substantially parallel to the field of view.

[0036] The wall may extend for a distance of at least about 3 cm, for example, at least about 4 cm, or at least about 5 cm, or at least about 6 cm, away from the proximity sensor.

[0037] The wall may extend around substantially all of an angular extent of the field of view of the proximity sensor (i.e. around substantially all of the solid angle).

[0038] The wall may be a wall at least partially defining the duct.The shade may be formed from a material which reflects and / or absorbs ambient light. For example, the material may be optically reflective and / or opaque.

[0039] The shade may be formed from a polymeric material.

[0040] The shade may be solid and non-perforated. That is to say, the shade may be a monolithic component configured to block the passage of light therethrough.

[0041] The at least one proximity sensor assembly may be mounted on (e.g. fixedly attached to) the mobile unit.

[0042] The mobile autonomous agricultural system may comprise a plurality of said proximity sensor assemblies distributed around the mobile unit.

[0043] The mobile autonomous agricultural system may comprise one or more of said proximity sensor assemblies positioned on one or more sides of the mobile unit. A proximity sensor assembly positioned on a side of the mobile unit may be oriented such that the field of view is projected substantially vertically downwards towards the ground.

[0044] The mobile autonomous agricultural system may comprise one or more of said proximity sensor assemblies positioned on one or more corners of the mobile unit. A proximity sensor assembly positioned on a corner of the mobile unit may be oriented such that the field of view is projected towards the ground at an angle intermediate horizontal and vertical.

[0045] In some examples, the mobile autonomous agricultural system may comprise a plurality of said proximity sensor assemblies distributed around the mobile unit, each proximity sensor having a field of view which overlaps with the field of view of at least one other proximity sensor of the plurality of proximity sensor assemblies.

[0046] For example, the mobile autonomous agricultural system may comprise a plurality of said proximity sensor assemblies distributed around the mobile unit, each proximity sensor assembly comprising a laser scanner, wherein each laser scanner has a field of view (e.g. a laser plane) which overlaps with the field of view (e.g. laser plane) of at leastone other laser scanner of the plurality of proximity sensor assemblies. Such an arrangement may form a laser curtain.

[0047] The mobile autonomous agricultural system may comprise a safety module configured to generate a safety output in response to the proximity sensor(s) detecting the presence of an object in the vicinity of the mobile autonomous agricultural system (e.g. in the vicinity of the mobile unit).

[0048] The safety output may comprise a signal to control the powered mobile unit to slow or to stop and / or a signal to cease use of agricultural equipment carried by the powered mobile unit.

[0049] The safety module may form part of the controller.

[0050] The mobile autonomous agricultural system may comprise a power supply for supplying power to at least one proximity sensor assemblies.

[0051] The mobile autonomous agricultural system may comprise at least one robot arm configured to perform agricultural tasks. The mobile autonomous agricultural system may comprise at least one UV lighting panel.

[0052] In a second aspect, there is provided a method of operating the mobile autonomous agricultural system according to the first aspect. The method of operating the mobile autonomous agricultural system may be a method of agriculture.

[0053] The method comprises operating the proximity sensor while the air mover blows air into and / or around the field of view of the proximity sensor.

[0054] The method may further comprise the air mover blowing the air into and / or around the field of view of the proximity sensor to remove and / or repel movable debris from the field of view. The movable debris may include one or more animals, for example, one or more small animals, such as one or more arthropods, for example, one or more (e.g. flying) insects or spiders.The method may further comprise the air mover blowing air into and / or around the field of view such that a velocity of a flow of air at a point within the field of view at a distance of 16 cm from the proximity sensor is at least about 0.5 m / s, for example, at least about 1.0 m / s, or at least about 1.5 m / s, or at least about 2.0 m / s.

[0055] The method may further comprise filtering air entering and / or exiting the air mover.

[0056] The method may further comprise shading the proximity sensor from exposure to ambient light, for example, sunlight, while operating the proximity sensor.

[0057] The method may further comprise generating a safety output in response to the proximity sensor detecting the presence of an object in the vicinity of the mobile autonomous agricultural system.

[0058] The safety output may comprise a signal to control the powered mobile unit to slow or to stop and / or a signal to cease use of agricultural equipment carried by the powered mobile unit.

[0059] The method may include any features as described hereinabove, mutatis mutandis, with reference to the first aspect.

[0060] In a third aspect, there is provided a proximity sensor assembly suitable for use in the mobile autonomous agricultural system of the first aspect or in the method of the second aspect. The proximity sensor assembly may have any of the components, features and / or functionalities as described hereinabove, mutatis mutandis, with regard to the first and / or second aspects. The proximity sensor assembly may be configured for mounting onto the powered mobile unit.

[0061] In a fourth aspect, there is provided a kit of parts for assembling the proximity sensor assembly according to the third aspect. The kit of parts includes the proximity sensor and the air mover. The kit of parts may further include any other components described hereinabove, mutatis mutandis, with regard to the first aspect.

[0062] In a fifth aspect, there is provided a kit of parts for use in assembling the proximity sensor assembly according to the third aspect, wherein the kit of parts does not include theproximity sensor. The kit of parts includes the air mover. The kit of parts may further include any other components described hereinabove (except for the proximity sensor), mutatis mutandis, with regard to the first aspect.

[0063] Figures

[0064] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0065] Figure 1 shows perspective views of a mobile autonomous agricultural system;

[0066] Figure 2 shows (a) a side view and (b) a front view of the mobile autonomous agricultural system of Figure 1;

[0067] Figure 3 shows a perspective view of a mobile autonomous agricultural system;

[0068] Figure 4 shows a front view of the mobile autonomous agricultural system of Figure 3;

[0069] Figure 5 shows a side view of the mobile autonomous agricultural system of Figure 3.

[0070] Figure 6 shows (a) a perspective view of a side safety laser scanner assembly and (b) a perspective view of the side safety laser scanner assembly indicating the field of view;

[0071] Figure 7 shows (a) a top view and (b) a bottom view of the side safety laser scanner assembly of Figure 6;

[0072] Figure 8 shows (a) a front view and (b) a side view of the side safety laser scanner assembly of Figure 6;

[0073] Figure 9 shows a top view of the side safety laser scanner assembly of Figure 6 with air intakes removed;

[0074] Figure 10 shows a cross-sectional view of the side safety laser scanner assembly of Figure 6;Figure 11 shows a further cross-sectional view of the side safety laser scanner assembly of Figure 6, illustrating the field of view;

[0075] Figure 12 shows a schematic cross-sectional view of the conduits and duct of the side safety laser scanner assembly of Figure 6, illustrating the field of view; and

[0076] Figure 13 shows a perspective view of a corner safety laser scanner assembly mounted on a portion of a mobile unit.

[0077] Detailed description

[0078] Figures 1 and 2 show a mobile autonomous agricultural system 10 comprising a powered mobile unit 12. The mobile autonomous agricultural system 10 is configured to operate along rows 40 of crops (illustrated in Figure 2 (b), with each row 40 shown extending into the page) to perform agricultural tasks, such as harvesting, husbandry, sanitisation or monitoring the crops.

[0079] In this example, the mobile unit 12 comprises an arch profile extending along an axial direction 50. In other words, at any point in the axial direction, a cross section of the mobile unit 12 comprises an arch profile. In this example, distal ends of arms of the arch are fixed to powered wheels 14 (which are pivotable with respect to the mobile unit 12 for steering) and extend away from the wheels 14 to an apex of the arch. In this example, each distal end of the arch is attached to two wheels 14, such that the whole arch is supported on the ground by a total of four wheels 14. It will be appreciated that in other examples, any suitable number of wheels may be used, or any other suitable device for propelling the mobile unit 12 may be used.

[0080] The arch profile of the mobile unit 12 defines an inner zone 16, in the form of a tunnel extending along the axial direction 50, within which agricultural equipment may be disposed such that it is protected from damage. The agricultural equipment in this example includes a robot arm 22 and two ultraviolet (UV) lighting panels 100 and 102 comprising UV lighting tubes 106.

[0081] The arch profile further allows the mobile unit 12 to traverse along rows 40 of crops, which are raised above the ground on posts (for ease of accessibility), with a single row40 of crops extending through the inner zone 16 along the axial direction 50, and simultaneously accessible by the agricultural equipment from two sides of the row 40. In some examples, the crops may be disposed on the ground, and the mobile unit may comprise any suitable profile to access the crops on the ground.

[0082] The mobile autonomous agricultural system 10 comprises a controller 20 which is configured to control the travel of the mobile unit 12. In this example, in an autonomous mode, the controller 20 is configured to autonomously move the mobile unit 12 along the rows 40 of crops, and between the rows 40, where the rows may comprise a straight line of crops, or any other line of crops with a non-linear profile. In other words, the controller 20 is configured to align the axial direction 50 of the inner zone 16 of the mobile unit 12 with a first row 40 of crops such that the arch profile is centred and aligned with the row 40 of crops, and to move the mobile unit 12 to approach the first row 40, and continue to move the mobile unit 12 along the row 40, with the first row 40 received in the inner zone 16 until it reaches an end of the row 40. At the end of the row 40, the controller 20 is configured to control the mobile unit 12 to exit the row 40, travel a predetermined distance away from the row 40, and traverse towards an adjacent row 40 to begin the process again with the adjacent row 40. In this example, the mobile autonomous agricultural system 10 may also be operated in a manual mode, in which a user can manually control the movement of the mobile unit 12, for example up to a first row 40, at which point the user may activate the autonomous mode.

[0083] In this example, the autonomous mode of the mobile autonomous agricultural system 10 provides for autonomous movement between adjacent rows 40 of crops, in a single polytunnel of plants, and also from one polytunnel to another.

[0084] During this autonomous movement, it is important that people around the mobile autonomous agricultural system 10 are kept safe. For example, during the approach of the mobile unit 12 towards a row 40, there is a risk of crushing a person between the mobile unit 12 and the row 40. Further, there are also risks during movement of the mobile unit 12 along the row 40, and outside the row 40 which must be mitigated to ensure the safety of people around the mobile unit 12.

[0085] As a safety feature, the agricultural system 10 is therefore provided with a plurality of safety laser scanners 18 distributed around the mobile unit 12. In this example, thereare six safety laser scanners 18, with one corner safety laser scanner 18a disposed at each of four corners of the mobile unit 12, which in this example is by each wheel 14, and one side safety laser scanner 18b disposed on each side of the mobile unit 12 between two wheels 14 in the axial direction 50.

[0086] The safety laser scanners 18 are each configured to project a respective laser towards the ground within a substantially planar field of view of the respective safety laser scanner. Accordingly, each safety laser scanner 18 can be considered to project a respective laser plane towards the ground, and each laser plane overlaps with at least one other laser plane, so as together to form a laser curtain surrounding the mobile unit 12. Each safety laser scanner 18 can detect when its respective laser plane is interrupted by sensing reflected waves of emitted laser beam light. Accordingly, each safety laser scanner 18 functions as a proximity sensor operable to detect the presence of an object in the vicinity of the mobile unit 12.

[0087] Specifically, the two side safety laser scanners 18b project a laser plane close to vertically downwards such that the respective laser planes are not interrupted by the wheels 14 if the wheels are rotated by 90 degrees, and so that the respective laser planes are not interrupted by adjacent rows 40 when the mobile unit 12 is moving along a row 40. This helps to reduce the risk of erroneous generation of a safety output. When the distance between rows is larger, the side safety scanners may be angled away from the mobile unit, or when the distance between the rows is narrow and constraining, and the wheels are smaller or do not rotate, then the side safety laser scanners may be angled towards the mobile unit.

[0088] Each corner safety laser scanner 18a is configured to project a laser plane angled downwards with respect to the horizontal to project away from the mobile unit 12, such that each laser plane from each corner safety laser scanner 18a overlaps with the laser plane from an adjacent corner safety laser scanner 18a, and so that the laser plane from each side safety laser scanner 18b overlaps (or meets) with the laser planes from the adjacent corner safety laser scanners 18a.

[0089] This particular configuration of safety laser scanners 18 ensures that the mobile unit 12 is wholly surrounded by the laser curtain such that the presence of an object such as a person can be detected anywhere around the mobile unit 12. It will be appreciated thatthere may be any suitable number of laser sensors for the particular application of the mobile autonomous agricultural system, such as one safety laser scanner, or more than one safety laser scanner.

[0090] The mobile autonomous agricultural system 10 further comprises a location module (in this example, within the controller 20) which is configured to monitor a location of the mobile unit 12 relative to a row 40. The location module may comprise GPS or any other suitable sensor which can be used to identify the location of the mobile unit relative to a row.

[0091] The mobile autonomous agricultural system 10 further comprises a safety module (in this example, within the controller 20) which is configured to generate a safety output in response to one of the safety laser scanners detecting the presence of an object in the vicinity of the mobile unit 12 (i.e. , in response to determining that the corresponding laser has been interrupted within its field of view). The safety output can include: sending a signal to control the mobile unit 12 to stop; sending a signal to control the robot arm 22 to stop; and / or sending a signal to the controller to disable operation of the UV lighting panels 100 and 102. In some examples, the safety output signal may be to slow the mobile unit or to slow the robot arms. In other examples, the safety output may alternatively or additionally comprise producing an alarm, such as actuating an audible alarm on the mobile unit, or an alarm remote from the mobile unit to an operator, to alert the operator to the potential threat to safety of a person, or to alert the operator to the immobilising of the mobile unit or robot arms, such that they can restart the mobile unit or robot arms when it is determined to be safe again.

[0092] It will be appreciated that the location module, the safety module and the controller may be separate components or they can be incorporated into a single unit.

[0093] The safety laser scanners 18 may be adjusted to determine the distance of the laser curtain from the mobile unit 12. Typically, this distance is between about 1 m and 3 m.

[0094] It will be appreciated that, although it has been described that the profile of the mobile unit defines an arch with distal ends of the arch fixed to wheels, in other examples, the mobile unit may have any suitable profile, or the arch profile may be inverted so that a portion of the arch at the apex is fixed to wheels and the distal ends extend upwards,away from the wheels and the ground. This can be used in situations where the crops are suspended from above, such that an inner zone between arms of the arch receives the suspended crop, and the crop is accessible to agricultural equipment in the arch from two sides simultaneously. For these examples, and the specific example described above, the axial direction may be the direction on the mobile unit which is configured to be parallel to a row while the controller controls the mobile unit to move along the row.

[0095] Further, although it has been described that the profile of the mobile unit defines a single arch defining a single inner zone 16 for receiving a single row of crops 40, the mobile unit may have any suitable profile for receiving any particular number of rows of crops.

[0096] For example, Figures 3 to 5 show a mobile autonomous agricultural system 210 comprising a powered mobile unit 212. The mobile autonomous agricultural system 210 is configured to operate along three rows 240a, 240b, 240c of crops (illustrated in Figure 4, with each row 240a, 240b, 240c shown extending into the page) to perform agricultural tasks, such as harvesting, husbandry, sanitisation or monitoring the crops.

[0097] In this example, the mobile unit 212 comprises three arch profile portions 213a, 213b, 213c extending along an axial direction 250. In other words, at any point in the axial direction, a cross section of the mobile unit 212 comprises three arch profile portions 213a, 213b, 213c. In this example, distal ends of arms of the arch profile portion 213a, as well as a distal end of one arm of each of arch profile portions 213b and 213c, are fixed to powered wheels 214 (which are pivotable with respect to the mobile unit 212 for steering) and extend away from the wheels 214 to an apex of the corresponding arch. In this example, each distal end of the arch profile portion 213a is attached to two wheels 214, such that the whole mobile unit 212 is supported on the ground by a total of four wheels 214. It will be appreciated that in other examples, any suitable number of wheels may be used, or any other suitable device for propelling the mobile unit 212 may be used.

[0098] The three arch profile portions of the mobile unit 212 define corresponding inner zones 216a, 216b, 216c, in the form of three tunnels extending along the axial direction 250, within which agricultural equipment may be disposed such that it is protected from damage. The agricultural equipment in this example includes ultraviolet (UV) lighting panels 300a, 300b, 300c and 302a, 302b, 302c.The arch profile portions 213a, 213b, 213c allow the mobile unit 212 to traverse along rows 240a, 240b, 240c of crops, which are raised above the ground on posts (for ease of accessibility), with: a single row 240a of crops extending through the inner zone 216a along the axial direction 250, and simultaneously accessible by the agricultural equipment from two sides of the row 240a; a single row 240b of crops extending through the inner zone 216b along the axial direction 250, and simultaneously accessible by the agricultural equipment from two sides of the row 240b; and a single row 240c of crops extending through the inner zone 216c along the axial direction 250, and simultaneously accessible by the agricultural equipment from two sides of the row 240c. In some examples, the crops may be disposed on the ground, and the mobile unit may comprise any suitable profile portions to access the crops on the ground.

[0099] The inner zones 216a, 216b, 216c may therefore be considered illumination zones 216a, 216b, 216c for illuminating corresponding rows of crops 240a, 240b, 240c with UV light.

[0100] It will be appreciated that providing the mobile unit 212 with multiple profile portions 213a, 213b, 213c corresponding to multiple rows of crops 240a, 240b, 240c makes it possible to perform agricultural tasks (including directing UV light towards crops) on multiple rows of crops at the same time (i.e. concurrently). Accordingly, the rate at which crops can be processed (i.e. the number of crops (i.e. plants) or the total area of crops processed per unit time) can be increased without necessarily increasing the speed at which the mobile autonomous agricultural system 210 moves.

[0101] The mobile autonomous agricultural system 210 comprises a controller 220 which is configured to control the travel of the mobile unit 212. In this example, in an autonomous mode, the controller 220 is configured to autonomously move the mobile unit 212 along the rows 240a, 240b, 240c of crops, and between the rows 240a, 240b, 240c, where the rows may comprise a straight line of crops, or any other line of crops with a non-linear profile. In other words, the controller 220 is configured: to align the axial direction 250 of the mobile unit 212 such that the arch profile portion 213a is centred and aligned with the row 240a of crops, the arch profile portion 213b is centred and aligned with the row 240b of crops, and the arch profile portion 213c is centred and aligned with the row 240c of crops; and to move the mobile unit 212 to approach the rows 240a, 240b, 240c, and continue to move the mobile unit 212 along the rows 240a, 240b, 240c, with the row 240a received in the inner zone 216a, the row 240b received in the inner zone 216b, andthe row 240c received in the inner zone 216c, until it reaches an end of the rows 240a, 240b, 240c. At the end of the rows, the controller 220 is configured to control the mobile unit 212 to exit the rows, travel a predetermined distance away from the rows, and traverse towards an adjacent set of rows 240a, 240b, 240c to begin the process again with the adjacent rows. In this example, the mobile autonomous agricultural system 210 may also be operated in a manual mode, in which a user can manually control the movement of the mobile unit 212, for example up to a first set of rows 240a, 240b, 240c, at which point the user may activate the autonomous mode.

[0102] In this example, the autonomous mode of the mobile autonomous agricultural system 210 provides for autonomous movement between adjacent sets of rows 240a, 240b, 240c of crops, in a single polytunnel of plants, and also from one polytunnel to another.

[0103] In the example shown, the mobile unit 212 is covered by a cover 320 which also helps to prevent UV light escaping from the inner zones 216a, 216b, 216c (particularly in a direction opposing the primary illumination directions). However, it will be appreciated that in other examples, the UV lighting panels are themselves each provided with a cover, for example, mounted on or integrally formed with the support frame.

[0104] As a safety feature, the agricultural system 210 is provided with a plurality of safety laser scanners 218 distributed around the mobile unit 212. In this example, there are six safety laser scanners 218, with one corner safety laser scanner 218a disposed above each wheel 214, and one side safety laser scanner 218b disposed at a distal end of each lateral arch profile portion 213b, 213c.

[0105] The safety laser scanners 218 are each configured to project a respective laser plane towards the ground, and each laser plane overlaps with at least one other laser plane, so as together to form a laser curtain surrounding the mobile unit 212. Each safety laser scanner 218 can detect when its respective laser plane is interrupted by an object (for example, by a person or by agricultural equipment) by sensing reflected waves of emitted laser beam light.

[0106] The mobile autonomous agricultural system 210 further comprises a safety module (in this example, forming part of the controller 220) which is configured to generate a safety output in response to determining that the laser curtain is interrupted. The safety outputcan include: sending a signal to control the mobile unit 212 to stop; sending a signal to the controller to slow the mobile unit; and / or sending a signal to the controller to disable operation of the UV lighting panels. In other examples, the safety output may alternatively or additionally comprise producing an alarm, such as actuating an audible alarm on the mobile unit, or an alarm remote from the mobile unit to an operator, to alert the operator to the potential threat to safety of a person, or to alert the operator to the immobilising of the mobile unit, such that they can restart the mobile unit when it is determined to be safe again. It will again be appreciated that the safety module and the controller may be separate components, or they can be incorporated into a single unit.

[0107] The safety laser scanners 218 may be adjusted to determine the distance of the laser curtain from the mobile unit 212. This distance is typically from about 1 m to about 3 m.

[0108] It will be appreciated that in the example shown in Figures 3 to 5, the mobile unit 212 has a profile which includes three arch profile portions 213a, 213b, 213c defining inner zones 216a, 216b, 216c within which corresponding rows of crops 240a, 240b, 240c can be illuminated with UV light at the same time. However, in other examples, the mobile unit 212 takes any suitable profile (for example, defining any suitable number of inner / illumination zones) such that the desired number of rows of crops can be illuminated.

[0109] Further details of compatible autonomous agricultural systems, mobile units, safety curtains and control methods may be found in published United Kingdom Patent Application GB 2610184 A (A mobile autonomous agricultural system and method), which is hereby incorporated by reference in its entirety.

[0110] Figures 6 to 12 show in more detail a side safety laser scanner assembly 400 which may be used in place of the side safety laser scanner 18b or the side safety laser scanner 218b in the mobile autonomous agricultural systems 10 or 210.

[0111] The assembly 400 includes a safety laser scanner 401 mounted within a housing 402. The housing 402 includes a body 403 which forms a duct 404, ending in an open aperture 410. The assembly 400 further includes first and second centrifugal fans 405a and 405b, which are in fluid communication with the duct 404 via corresponding conduits 406a and 406b. The fans 405a and 405b are provided with air intakes 407a and 407b, which arefitted with corresponding air filters 408, of which only air filter 408b is shown in the Figures for clarity.

[0112] The safety laser scanner 401 is a device which, when operated, projects a laser beam within a fan-shaped field of view 409. The trajectory of the laser beam may be varied within this field of view 409 using a rotating mirror. When an object is present within the field of view 409, the safety laser scanner 401 is able to detect the object by sensing reflected laser light. The safety laser scanner 401 may also be able to determine the distance between the safety laser scanner 401 and the object, for example, using time-of-flight analysis. In the example being discussed, the safety laser scanner 401 is a safety laser scanner from the SZ or SZ-V ranges available from KEYENCE (UK) Ltd, of the United Kingdom. However, it will be appreciated that any suitable safety laser scanner may be used. Indeed, the safety laser scanner 401 could, in principle, be replaced by any suitable proximity sensor operable to detect the presence of an object in the vicinity of a mobile unit.

[0113] As can be seen in the Figures, the body 403 of the housing 402 is substantially hollow and includes an upper body portion 411 and a lower body portion 412 which together define the hollow duct 404. The safety laser scanner 401 and the body 403 are positioned relative to one another such that the duct 404 is positioned directly in front of a sensing face of the laser safety scanner 401 (i.e. the portion of the laser safety scanner 401 from which the laser beam is typically emitted when in use). The upper and lower body portions 411 and 412 are partially disc-shaped and extend radially outwards from the laser safety scanner 401 , on either side of the substantially planar field of view 409.

[0114] As illustrated in Figures 6(b), 10, 11 and 12, the housing 402 and, in particular, the body 403 and the duct 404, are configured (i.e. shaped, dimensioned and positioned relative to the safety laser scanner 401) so as not to obstruct or obscure the field of view of the safety laser scanner 401. Instead, the field of view 409 of the safety laser scanner 401 extends through the duct 404 and out through the open aperture 410. The presence of the housing 402 therefore does not negatively impact the functioning of the safety laser scanner 401.

[0115] In fact, the housing 402 contributes to protecting the safety laser scanner 401 from damage or optical interference when in use. In particular, because the upper and lowerbody portions 411 and 412 of the body 403 project away from the safety laser scanner 401, they function as shades which can shade the safety laser scanner 401 from exposure to ambient light (which may be, for example, sunlight which would either impinge directly on the safety laser scanner 401 or be reflected onto the safety laser scanner 401 from nearby surfaces (e.g. puddles of water)). By shading the safety laser scanner 401 from exposure to ambient light, the functioning of the safety laser scanner 401 may be improved (for example, the sensitivity of the device may be improved). In particular, it has been found that exposure to sunlight (whether direct or reflected) can impact the sensitivity of the light sensor of safety laser scanners and cause an error similar to “overexposure” of the sensor. Such an error can sometimes inadvertently trigger a safety output which causes operation of the mobile unit to stop, even though no object has been detected in the field of view 409. Use of the housing 402 to shade the safety laser scanner 401 and reduce exposure to ambient light therefore reduces the likelihood of this problem occurring without, for example, applying further optical filters to the safety laser scanner 401 itself (which are known to negatively impact device sensitivity). Indeed, the inventors have found that, when a shade as described herein is not used, some mobile units exhibit a tendency to stop moving for significant periods of time (for example, one hour) when (either direct or reflected) sunlight is incident on the safety laser scanner sensors. Such stoppage events can occur at different times of the day, depending on the angle of the sun, the time of year and the placement of the mobile unit. In contrast, the inventors have found that safety laser scanners incorporating shades as described herein do not suffer from this problem.

[0116] The fans 405a and 405b are connected to a power source (not shown) and operable to draw air from the surroundings through air intakes 407a and 407b and output a flow of air, through conduits 406a and 406b, into and through the duct 404. As shown in Figures 11 and 12, the conduits 406a and 406b are provided with vanes 413 which guide the air flow from the fans 405a and 405b through the conduits 406a and 406b and into the duct 404. The conduits 406a and 406b, the vanes 413 and the upper and lower body portions 411 and 412 are configured (i.e. shaped, dimensioned and positioned) to generate a flow of air, when the fans 405a and 405b are operated, which exits the duct 404 at the open aperture 410 and flows into and / or around the field of view 409.

[0117] By blowing air into and / or around the field of view 409, mobile debris which would otherwise be present within the field of view 409 may be removed or repelled. Forexample, it has been found that flying insects can be attracted to mobile autonomous agricultural systems (for example, they may be attracted to the lights of the systems at night) and spiders have been found to climb on and / or build webs on such systems. If these insects or spiders inadvertently pass through the field of view of a laser safety scanner, they can sometimes trigger a safety output which causes operation of the mobile unit to stop. However, by blowing air into and / or around the field of view, such flying insects and spiders can be kept out of the field of view, reducing the incidence of such erroneous stopping events. Indeed, the inventors have found that installing a fan system of this type was able to reduce the incidence of erroneous stopping events from around 150 occurrences per night of operation to fewer than 10 occurrences per night of operation.

[0118] In the example being discussed, the fans 405a and 405b are centrifugal fans, such as centrifugal fans in the San Ace B97 series available from SANYO DEN KI CO., LTD, of Japan. However, it will be appreciated that any suitable type of air moving device may be used, such as any suitable type of axial-flow fan, centrifugal fan, crossflow fan or bladeless fan. Moreover, while the present example includes two fans 405a and 405b positioned on either side of the safety laser scanner 401 , the assembly may in principle include only one air moving device or any number of air moving devices which may be positioned in any suitable way so as to blow air into and / or around the field of view. Similarly, it will be appreciated that any suitable conduit, vane and / or duct structure may be employed to guide the flow of air into and / or around the field of view. Indeed, in some embodiments, one or all of the conduit(s), vane(s) and / or duct(s) may not be present.

[0119] In the example being discussed, the air intakes 407a and 407b are fitted with corresponding air filters 408, of which only air filter 408b is shown in the Figures for clarity. In this example, the air filters 408 include a foam material which is configured to trap particulate material (e.g. dust) present in the air being drawn into the fans 405a and 405b from the surroundings. By trapping such particulate material in the air being drawn in via the intakes, the amount of particulate material present in the air flow blown through the conduits and the duct, and thus passing in front of the safety laser scanner 401, is reduced. It has been found that, when air filters are not used, particulate material present in the air flow can accumulate on the safety laser scanner and / or scratch one or more surfaces (e.g. of one or more sensing components) of the safety laser scanner and thus reduce the accuracy and / or sensitivity of the safety laser scanner. Including the air filters408 in the assembly therefore helps to protect the safety laser scanner from the accumulation of and / or damage caused by particulate matter in the air flow.

[0120] The fans 405a and 405b and housing 402 (including the body 403 which defines the shape of the duct 404 and the open aperture 410) are configured (i.e. powered, shaped, dimensioned and / or arranged, as appropriate) to generate sufficient air flow into and / or around the field of view 409 of the safety laser scanner 401 to remove and / or repel insects and spiders. In the example shown, the upper and lower body portions 411 and 412 are partially disc shaped and positioned in front of the safety laser scanner 401 so as to extend either side of (e.g. above and below) the field of view 409 and thus to sandwich the field of view 409 without obstructing the field of view 409.

[0121] In the example shown, the shape of the partially disc shaped upper and lower body portions 411 and 412 can be characterised by the radial distance D between the edge of the safety laser scanner 401 to the circumferential edge of the of upper or lower body portions 411 and 412, respectively, along a radial line which extends radially from the centre point of the safety laser scanner 401 to the circumferential edge of the upper or lower body portions 411 and 412, as the case may be, when the safety laser scanner assembly 400 is viewed from above or below along an axis perpendicular to the field of view 409. The radial distance D is illustrated in Figure 7(a). In the example shown, D is about 60 mm.

[0122] In the example shown, the open aperture 410 can be characterised by the spacing S between the upper and lower body portions 411 and 412 at the open aperture 410, which is the perpendicular distance between the circumferential edges of the upper and lower body portions 411 and 412. The spacing S is illustrated in Figure 8 (b). In the example shown, S is about 9 mm. In this example, the spacing S is substantially uniform around the entire circumferential edge.

[0123] The air flow into and / or around the field of view 409 can be characterised by the air velocity measured at one or more locations within the field of view 409. Air velocity can be measured using a wind anemometer. In the present example, the inventors measured the air velocity at five different points Pi , P2, P3, P4 and P5 around the safety laser scanner assembly 400, as illustrated in Figure 9. Each of these points lay within the plane of the field of view 409 on an arc A which had a constant normal distance of100 mm from the circumferential edges of the upper and lower body portions 411 and 412 (i.e. the arc A was “parallel” to the curved circumferential edges). The air velocity was measured using a commercially available hand-held low-speed vane-based wind anemometer. At each measurement point, the vane portion of the anemometer was positioned facing radially inwards towards the safety laser scanner 401 to measure the velocity of the air flowing radially outwards through the open aperture. For the example shown, the values obtained were: P 4.5 m / s; P2: 5.7 m / s; P3: 2.3 m / s; P4: 5.6 m / s; and Ps: 4.5 m / s. A substantially symmetric distribution of air flow velocity was therefore observed. When tested after mounting on a mobile unit, a safety laser scanner assembly of this type was found to generate sufficient air flow to remove and / or repel flying insects and spiders.

[0124] The components of the safety laser scanner assembly 400 may be manufactured using any suitable materials and / or methods. In the example shown, the housing 402 (including the body 403) and the air intakes 407a and 407b are 3D printed from a polymeric material. However, it will be appreciated that these components could also be made from, for example, metal. Moreover, it will be appreciated that these components could be, for example, injection moulded, cast, machined, etc. The various components could be integrally formed with one another (for example, cast or moulded as a single piece) or the components could be assembled and attached to one another, for example, using adhesives, welding, fastening mechanisms, etc.

[0125] It will be appreciated that the assembly 400 in the present example serves at least two distinct functions. In particular, the assembly serves to shade the safety laser scanner 401 from exposure to ambient light (to thus protect the safety laser scanner 401 from overexposure) and the assembly also serves to blow air into the field of view of the safety laser scanner 401 to remove and / or repel movable debris (to thus reduce the occurrence of erroneous stopping events). However, it will be appreciated that alternative assemblies can be envisaged which provide only one of these functions. For example, the assembly may include one or more shades configured to shade the safety laser scanner from exposure to ambient light, but the assembly may not comprise any air moving device for blowing air into and / or around the field of view. Alternatively, the assembly may include one or more air moving devices for blowing air into and / or around the field of view of the safety laser scanner, but the assembly may not comprise any shades for shading the safety laser scanner from exposure to ambient light.Moreover, many other variations of the assembly 400 would be readily apparent to the person skilled in the art, dependent on the desired function. For example, the shape and dimensions of the housing may be varied based on the particular type of proximity sensor used and, in particular, based on the shape and dimensions of the field of view of said sensor. Additionally or alternatively, the shape and dimensions of the housing may be varied based on the number and type of air moving devices (e.g. fans) used, if any, and, in particular, based on the power and orientation of said air moving device(s). The shape and dimensions of the housing may be varied to generate a desired flow of air into and / or around the field of view, for example, to generate a particular air flow velocity (e.g. as measured at a particular point in the field of view) or a particular air flow velocity distribution.

[0126] The safety laser scanner assembly 400 is a side safety laser scanner assembly intended for mounting on each side of a mobile unit 12 or 212. However, Figure 13 illustrates a corner safety laser scanner assembly 500 mounted on a corner of a mobile unit 12 or 212.

[0127] The corner safety laser scanner assembly 500 has essentially the same components, structure and function as the side safety laser scanner assembly 500. However, the corner safety laser scanner assembly 500 is configured to be mounted at the corner of a mobile unit and may be arranged so as to project a laser plane angled downwards with respect to the horizontal to project away from the mobile unit, whereas a side safety laser scanner assembly 400 may be arranged to project a laser plane close to vertically downwards.

[0128] The corner safety laser scanner assembly 500 includes a safety laser scanner 501 mounted within a housing 502. The housing 502 includes a body 503 which forms a duct 504, ending in an open aperture 510. The assembly 500 further includes first and second centrifugal fans 505a and 505b, which are in fluid communication with the duct 504 via corresponding conduits 506a and 506b. The fans 505a and 505b can be provided with air intakes and corresponding air filters, which are not shown in Figure 13.

[0129] It will be understood that the invention is not limited to the embodiments described above and various modifications and improvements can be made without departing from theconcepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

Claims

Claims1. A mobile autonomous agricultural system comprising:a powered mobile unit for carrying agricultural equipment, and configured to move along rows of crops;a controller configured to control the travel of the mobile unit; and at least one proximity sensor assembly comprising:a proximity sensor configured to detect the presence of an object in the vicinity of the mobile autonomous agricultural system; andan air mover configured to blow air into and / or around a field of view of the proximity sensor.

2. The mobile autonomous agricultural system according to claim 1, wherein the proximity sensor is an optical proximity sensor, for example, a laser scanner, optionally wherein the laser scanner is configured to emit laser light within a plane which defines the field of view.

3. The mobile autonomous agricultural system according to claim 1 or claim 2, wherein the air mover is configured to blow air into and / or around the field of view of the proximity sensor to remove and / or repel movable debris from the field of view.

4. The mobile autonomous agricultural system according to claim 3, wherein the movable debris includes one or more animals, for example, one or more arthropods, for example, one or more insects or spiders.

5. The mobile autonomous agricultural system according to any preceding claim, wherein the air mover is configured to blow air into and / or around the field of view such that a velocity of a flow of air at a point within the field of view at a distance of 16 cm from the proximity sensor is at least about 0.5 m / s.

6. The mobile autonomous agricultural system according to any preceding claim, wherein the air mover is a fan, for example, an axial-flow fan, a centrifugal fan, a crossflow fan or a bladeless fan.

7. The mobile autonomous agricultural system according to any preceding claim, wherein the at least one proximity sensor assembly comprises an air filter configured to filter air entering and / or exiting the air mover.

8. The mobile autonomous agricultural system according to any preceding claim, wherein the at least one proximity sensor assembly comprises a body which defines a duct having an open aperture, wherein the body and the proximity sensor are positioned relative to one another such that the field of view of the proximity sensor extends through the duct and out through the open aperture, and wherein the air mover is configured to blow air into and through the duct and out of the open aperture.

9. The mobile autonomous agricultural system according to claim 8, wherein the duct is configured to direct air flow out of the open aperture into and / or around the field of view of the proximity sensor outside the body.

10. The mobile autonomous agricultural system according to claim 8 or claim 9, wherein the at least one proximity sensor assembly comprises one or more vanes configured to direct air flow from the air mover into and / or through the duct.

11. The mobile autonomous agricultural system according to any preceding claim, wherein the at least one proximity sensor assembly comprises two air movers positioned on either side of the proximity sensor and configured to blow air into and / or around the field of view of the proximity sensor.

12. The mobile autonomous agricultural system according to any preceding claim, wherein the at least one proximity sensor assembly comprises a shade configured to shade the proximity sensor from exposure to ambient light, for example, sunlight.

13. The mobile autonomous agricultural system according to claim 12, where dependent on any of claims 8 to 10, wherein the body comprises a wall which functions as the shade.

14. The mobile autonomous agricultural system according to any preceding claim, wherein the mobile autonomous agricultural system comprises a plurality of said proximity sensor assemblies distributed around the mobile unit.

15. The mobile autonomous agricultural system according to any preceding claim, wherein the mobile autonomous agricultural system comprises a safety module configured to generate a safety output in response to the proximity sensor detecting the presence of an object in the vicinity of the mobile autonomous agricultural system.

16. The mobile autonomous agricultural system according to claim 15, wherein the safety output comprises a signal to control the powered mobile unit to slow or to stop and / or a signal to cease use of agricultural equipment carried by the powered mobile unit.

17. A method of operating the mobile autonomous agricultural system according to any preceding claim, the method comprising operating the proximity sensor while the air mover blows air into and / or around the field of view of the proximity sensor.

18. The method according to claim 17, further comprising the air mover blowing the air into and / or around the field of view of the proximity sensor to remove and / or repel movable debris from the field of view.

19. The method according to claim 18, wherein the movable debris includes one or more animals, for example, one or more arthropods, for example, one or more insects or spiders.

20. The method according to any of claims 17 to 19, further comprising the air mover blowing air into and / or around the field of view such that a velocity of a flow of air at a point within the field of view at a distance of 16 cm from the proximity sensor is at least about 0.5 m / s.

21. The method according to any of claims 17 to 20, further comprising filtering air entering and / or exiting the air mover.

22. The method according to any of claims 17 to 21, further comprising shading the proximity sensor from exposure to ambient light, for example, sunlight, while operating the proximity sensor.

23. The method according to any of claims 17 to 22, further comprising generating a safety output in response to the proximity sensor detecting the presence of an object in the vicinity of the mobile autonomous agricultural system.

24. The method according to claim 23, wherein the safety output comprises a signal to control the powered mobile unit to slow or to stop and / or a signal to cease use of agricultural equipment carried by the powered mobile unit.

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