Robotic arm and picking platform

Abstract

A robotic arm 210 for picking fruit 300 or vegetables from a plant. The robotic arm comprises a proximal end for attachment to a robotic picking platform and a distal end for positioning adjacent a fruit or vegetable to be picked, which distal end comprises an end-effector 215 adapted to pick the fruit or vegetable from a volume 250 adjacent the distal end. A position sensor system 238 e.g. a stereo camera system facilitates detection of the position of the fruit or vegetable relative to the volume at said distal end. The position sensor and said end-effector are configurable by relative movement between said position sensor and said end-effector into a first configuration Fig, 9b, in which operation of the end-effector would grasp a fruit or vegetable within the volume and a second configuration, fig. 9a, in which operation of the end-effector would not grasp a fruit or vegetable within said volume. Moving the effector away from the volume improves visibility of the fruit.

Description

TECHNICAL FIELD This invention relates to a robotic arm for picking an object, such as a fruit or vegetable from a plant, to a robotic picking platform comprising a robotic arm, and to a method of picking fruit or vegetables from a plant. BACKGROUND WO 2022 / 263456 discloses an end-effector for a robotic arm in which a membrane is inflatable to grasp an object, such as a fruit or vegetable. The end-effector comprises an internal volume for receiving a fruit or vegetable to be picked. The flexible membrane is located within the internal volume and defines an aperture and an inflatable volume. The membrane is configurable to increase the inflatable volume from an uninflated configuration to an inflated grasping configuration to thereby narrow the aperture and permit a fruit or vegetable within the internal volume to be grasped. The end-effector comprises two position sensors that provide feedback to a control system to facilitate correct positioning of the end-effector prior to picking the fruit or vegetable. The position sensors are fixed to and move with the end-effector. The present inventors have identified several problems with this arrangement, including that it is difficult to be sure whether the fruit or vegetable has entered the end-effector which reduces picking efficiency, and that the end-effector may catch a support system (such as a strings or wires) that support the plant in the growing environment. SUMMARY OF THE INVENTION According to some embodiments there is provided a robotic arm for picking fruit or vegetables from a plant. The robotic arm may comprise a proximal end for attachment to a robotic picking platform. The robotic arm may comprise a distal end for positioning adjacent a fruit or vegetable to be picked. The distal end may comprise an end-effector adapted to pick a fruit or vegetable from a volume adjacent the distal end. The distal end may comprise a position sensor for facilitating detection of the position of the fruit or vegetable relative to the volume at the distal end. The position sensor and the end-effector may be configurable, for example by relative movement between said position sensor and said endeffector, into a first configuration in which operation of the end-effector would grasp a fruit or vegetable within said volume and a second configuration in which operation of the endeffector would not grasp a fruit or vegetable within said volume. It may be that substantially the entirety or each fruit or vegetable is to be positioned within the volume. Alternatively it may be that only a part of the fruit or vegetable (such as the centroid of its shape) may be located within the volume. In some embodiments the arrangement may be such that in said second configuration a view of the fruit or vegetable by said position sensor is substantially uninhibited by said end-effector and in said first configuration said view is at least partly inhibited. In some embodiments said position sensor may have a field of view. The arrangement may be such that in said second configuration the end-effector is substantially outside at least a portion of said field of view and in said first configuration at least a part of the end-effector may be within said portion of said field of view. In some embodiments the at least a portion of the field of view may comprise a region encompassing a centre of the field of view. In some embodiments said at least a portion of the field of view may comprise a fraction of the entire field of view. In some embodiments said at least a portion of the field of view may comprise substantially the entire field of view. In some embodiments in said second configuration said at least a part of the end-effector may be visible within a periphery of said field of view. In some embodiments said at least a portion of the field of view may correspond to said volume adjacent the distal end of the robotic arm. In some embodiments, when the distal end of the robotic arm is positioned adjacent the fruit or vegetable to be picked there may be a line of sight between said position sensor and said fruit or vegetable. The line of sight may be substantially clear when the end-effector is in the second configuration. The at least a part of said end-effector may interrupt the line of sight when in said first configuration. In some embodiments the end-effector may be moveable independently of said position sensor. In some embodiments the position sensor may be fixed relative to said robotic arm. The end-effector may be moveable relative to said position sensor. In some embodiments the end-effector may comprise a housing defining an internal volume into which the fruit or vegetable is to be received. In some embodiments, when said fruit or vegetable to be picked is located within said volume adjacent the distal end of the robotic arm, movement of the end-effector from the second configuration to the first configuration puts said fruit or vegetable within said internal volume of said end-effector. In some embodiments when the fruit or vegetable to be picked is received in said internal volume, the housing may obscure the view by the position sensor of the fruit or vegetable. In some embodiments said end-effector may further comprise a flexible membrane within the internal volume. The membrane may define an aperture and an inflatable volume. The membrane may be configurable to increase the inflatable volume from an uninflated configuration to an inflated grasping configuration to thereby narrow the aperture and permit the fruit or vegetable within the internal volume to be grasped. In some embodiments the relative movement between the position sensor and the endeffector between the first and second configurations may occur only with movement of the end-effector and without any movement of the robotic arm. In some embodiments the end-effector may further comprise a storage volume for temporary storage of at least one fruit or vegetable after picking. In some embodiments the storage volume may be arranged to catch said at least one fruit or vegetable as it falls under gravity after picking. In some embodiments the robotic arm may further comprise a lid that is openable to release said at least one fruit or vegetable from the storage volume, and that is closeable thereafter. In some embodiments the lid may be openable when said end-effector and said position sensor are in said second configuration. In some embodiments the robotic arm may further comprise an actuator for moving said end-effector between said first and second configurations and for opening and closing said lid. In some embodiments the actuator may comprise a single actuator. Operation of the actuator in a first direction or sense may cause said end-effector to move from said first configuration to said second configuration and then to open said lid whilst a housing of said end-effector remains stationary. Operation of said actuator in a second direction or sense opposite to said first direction or sense may cause the lid to close whilst said housing remains stationary, and then said end-effector to move from said second configuration to said first configuration. In some embodiments the robotic arm may further comprise a mechanism for disengaging said housing from said actuator at said first configuration when said actuator operates in said first direction or sense, and for re-engaging said housing to said actuator at said first configuration when said actuator operates in said second direction. In some embodiments said mechanism may comprise a gear. The gear may comprise a toothed portion and a toothless portion. In some embodiments the robotic arm may be adapted to move and position the endeffector within a plane. In some embodiments the robotic arm may further comprise a first segment, a second segment and a first revolute joint between the first and second segments. In some embodiments the robotic arm may further comprise a second revolute joint for facilitating rotation of said robotic arm when attached to the robotic picking platform. In some embodiments the position sensor may comprise an image sensor. In some embodiments the image sensor may provide an output signal representing detection of a visible and / or a non-visible wavelength of the electromagnetic spectrum. In some embodiments depth data is obtainable from an output provided by said image sensor. In some embodiments said image sensor may comprise at least two image sensors adapted to provide an output suitable for generating a computer-processable stereoscopic image. In some embodiments said at least two image sensors may be oriented so that the view of one image sensor at least partly overlaps with the view of the other. Each image sensor may be oriented toward said volume adjacent the end of the distal end of the robotic arm. In some embodiments the image sensor may be displaced from a plane in which said robotic arm is moveable. In some embodiments the image sensor may comprises any one or a combination of a 3D camera, a stereo camera, a structured light camera, a holographic camera, or a LIDAR scanner. In some embodiments movement between said first configuration and said second configuration comprises at least one of a rotation movement, a non-linear movement and a linear movement. In some embodiments the end-effector may be moveable relative to said robotic arm along a path between said first configuration and said second configuration. The path may cross or contain said volume adjacent the distal end of said robotic arm. In use, the fruit or vegetable may be positioned within said volume on said path and movement of said endeffector from said second configuration to said first configuration along said path captures the fruit or vegetable. According to some embodiments there is provided a robotic picking platform for picking fruit or vegetables from a plant. The robotic picking platform may comprise a mobile base. The robotic picking platform may comprise a storage system mounted on the mobile base. The robotic picking platform may comprise at least one robotic arm as set out above, or as described or as claimed anywhere herein. The at least one robotic arm may be controllable to pick fruit or vegetables and deliver picked fruit or vegetables to the storage system. In some embodiments the robotic picking platform may further comprise at least one linear actuator mounted on the mobile base. The at least one robotic arm may be mounted to said at least one linear actuator so that the at least one robotic arm is moveable in a generally up and down direction when the robotic picking platform is in use. In some embodiments the robotic picking platform may further comprise a platform-based position sensor mounted on said mobile base. The platform-based position sensor may be oriented for facilitating detection of the position of a fruit or vegetable on a plant adjacent the robotic picking platform. In some embodiments the platform-based position sensor may be adapted to inspect substantially the entire height of said fruit or vegetable bearing plant during use. In some embodiments the platform-based position sensor may comprise a platform-based image sensor. In some embodiments the platform-based image sensor may be adapted to provide an output signal representing detection of a visible and / or a non-visible wavelength of the electromagnetic spectrum. In some embodiments depth data may be obtainable from an output provided by said platform-based image sensor. In some embodiments the platform-based image sensor may comprise at least two platform-based image sensors adapted to provide an output suitable for generating a computer-processable stereoscopic image. In some embodiments the at least two platform-based image sensors may be oriented so that the view of one platform-based image sensor at least partly overlaps with the view of the other. Each platform-based image sensor may be oriented toward said volume adjacent the end of the distal end of the robotic arm. In some embodiments the platform-based image sensor may comprise a 3D camera, a stereo camera, a structured light camera, a holographic camera, or a LIDAR scanner. In some embodiments said robotic picking platform may further comprise a control system comprising a processor. The control system may be adapted to process an output signal from said position detector to determine a position of a fruit or vegetable on a plant adjacent the robotic picking platform. The control system may be adapted so that, with said position sensor and said end-effector in said second configuration, the at least one robotic arm is moved so that a distal end of the robotic arm is adjacent said position. In some embodiments the control system may be further adapted to process an output signal from the position sensor on the at least one robotic arm, and to move said at least one robotic arm so that said fruit or vegetable is located within said volume adjacent the distal end of the at least one robotic arm. In some embodiments the control system may be further adapted to perform image-based servoing using said output signal. In some embodiments the control system may be adapted to change said position sensor and said end-effector from said second configuration to said first configuration, and then to determine whether said fruit or vegetable is within the end-effector after said change. In some embodiments thew robotic picking platform may further comprise an autonomous navigation system for controlling navigation of said mobile base during a fruit or vegetable picking operation. According to some embodiments there is provided a vertical farming system. The vertical farming system may comprise at least one robotic arm as set out above, or as described or as claimed anywhere herein. The at least one robotic arm may be controllable to pick fruit or vegetables from the vertical farming system. According to some embodiments there is provided a method of picking a fruit or vegetable from a plant using a robotic arm as set out above, or as described or as claimed anywhere herein. The method may comprise the step of, with the position sensor and the end-effector in said second configuration, moving the robotic arm so that the fruit or vegetable is within said volume adjacent the distal end of the robotic arm. The method may comprise the step of changing the position sensor and the end-effector to said first configuration. The method may comprise the step of grasping said fruit or vegetable with said end-effector. In some embodiments the method may further comprise the step of picking the fruit or vegetable by changing the position sensor and the end-effector from said first position to said second position whilst said fruit or vegetable is grasped by the end-effector. In some embodiments the robotic arm may remain substantially stationary during said grasping step and during said picking step. In some embodiments said robotic arm may be moved during and / or just after said picking step. In some embodiments the step of moving said robotic arm may comprise a downwards and / or an outwards movement. In some embodiments the fruit or vegetable may be of a type that hangs from a stem or branch under its own weight. In some embodiments the fruit may comprises a soft fruit. The soft fruit may be a berry. The berry may be a raspberry and a blackberry. According to some embodiments there is provided a robotic arm for picking an object. The robotic arm may comprise a proximal end for attachment to a robotic picking platform. The robotic arm may comprise a distal end for positioning adjacent an object to be picked. The distal end may comprise an end-effector adapted to pick an object from a volume adjacent said distal end. The distal end may comprise a position sensor for facilitating detection of the position of the object relative to the volume at the distal end. The position sensor and said end-effector may be configurable, for example by relative movement between said position sensor and said end-effector, into a first configuration in which operation of the end-effector would grasp an object within said volume and a second configuration in which operation of the end-effector would not grasp an object within said volume. According to some embodiments there is provided a robotic arm for picking fruit or vegetables. The robotic arm may comprise a proximal end for attachment to a robotic picking platform. The robotic arm may comprise a distal end for positioning adjacent a fruit or vegetable to be picked. The distal end may comprise an end-effector adapted to pick the fruit or vegetable, for example from a volume adjacent said distal end. The distal end may comprise a position sensor. The position sensor may have a field of view. The position sensor may facilitate detection of the position of the fruit or vegetable relative to the distal end of the robotic arm just prior to picking. The position sensor and the end-effector may be configurable between a first configuration in which at least a part of the end-effector is within said portion of said field of view. The position sensor and the end-effector may be configurable between a second configuration in which the end-effector is substantially outside at least a portion of said field of view. In some embodiments the position sensor and the end-effector may be configurable such that in the second configuration a view of the fruit or vegetable by said position sensor is substantially uninhibited by said end-effector, and a second configuration in which said view is at least partly inhibited. In some embodiments the end-effector may be moveable, for example relative to the position sensor, between a first configuration in which the end-effector is visible to the position sensor and a second configuration in which the end-effector is not visible to said position sensor. In some embodiments the position sensor and said end-effector may be configurable between a first configuration in which the end-effector is detectable by the position sensor and a second configuration in which the end-effector is substantially undetectable by the position sensor. According to some embodiments there is provided a robotic arm for picking fruit or vegetables. The robotic arm may comprise a proximal end for attachment to a robotic picking platform. The robotic arm may comprise a distal end for positioning adjacent a fruit or vegetable to be picked. The distal end may comprise an end-effector adapted to pick the fruit or vegetable. The distal end may comprise a position sensor. The position sensor may have a field of view. The position sensor may facilitate detection of the position of the fruit or vegetable relative to the distal end of the robotic arm just prior to picking. During a picking process, the position sensor may be fixed in the frame of reference of the robotic arm, while the end-effector may be movable relative to the position sensor. Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", mean "including but not limited to", and do not exclude other components, integers or steps. Moreover the singular encompasses the plural unless the context otherwise requires: in particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Preferred features of each aspect of the invention may be as described in connection with any of the other aspects. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a photograph of a typical system of polytunnels used to grow fruit plants; Fig. 2 is an example specification for a system of polytunnels and fruit plants grown in the polytunnels; Fig. 3 is an isometric view of a robotic picking platform comprising robotic picking arms suitable according to an embodiment of the invention; Fig. 4A is an isometric view of a robotic picking arm according to an embodiment of the invention; Fig. 4B is a schematic side view of the robotic picking arm of Fig. 4A; Fig. 4C is a schematic plan view of the robotic picking arm of Fig. 4A; Figs. 5A, 5C and 5C are schematic illustrations of example paths along which an endeffector of the robotic arm is moveable; Figs. 6A, 6B &6C are schematic cross section views of the robotic picking arm of Fig. 4 in three different configurations; Fig. 7 is an isometric view of part of an end-effector of the robotic arm of Figs. 4A -4C; Figs. 8A, 8B and 8C are isometric views of the end-effector of Fig. 8 in three different configurations; Figs. 9A and 9B illustrates operation of the end-effector of Figs. 4A - 4C. DETAILED DESCRIPTION Some embodiments of the present invention provide a robotic arm suitable for use in a robotic system for plucking / picking / harvesting fruit and / or vegetables. Although embodiments below are described principally in relation to robotic systems for picking soft fruits such as raspberries and blackberries, it will be noted that the robotic arm may be used for picking / harvesting other fruits and vegetables. In other aspects, robotic arms according to various embodiments of the invention may be used for grasping and picking objects generally and the invention (as set out anywhere herein, either in the description or claims) should not be regarded as limited to picking fruits and vegetables. Some embodiments of the robotic arm may be used for picking / harvesting fruits and / or vegetable from plants on which a peduncle supports a solitary fruit or vegetable. In some embodiments the torus (i.e. the receptacle or stem) may or may not stay with fruit or vegetable as it is picked. For example, a blackberry is an example of the former and a raspberry is an example of the latter. Fig. 1 illustrates an example of a polytunnel system 100 used for growing fruit or vegetables commercially. The kind of polytunnel system illustrated is sometimes known as a 'fruit tunnel'. The polytunnel system 100 comprises a lightweight roof structure 102 having plurality arcuate cross members 104 spaced along a ridge member 106. Posts 108 are positioned along the length of the polytunnel system to support the roof structure 102 at each end of the arcuate cross members 104. In some polytunnel systems, the arcuate cross members 104 extend all the way to the ground and posts 108 are not used. Translucent sheeting 110 (not shown), such as polythene is placed over the arcuate cross members to at least partially enclose the space underneath to provide a protected environment for growing fruits and vegetables. Row of plants 110 are grown within the polytunnel system 100. Raspberries are typically grown in pots. Shoots rise vertically from the pots with lateral branches growing roughly horizontally outwardly from the shoots. The lateral branches carry the foliage and raspberries. A support system 112 (such as a strings or nets) may be used to support the lateral branches as they grow and bear fruit. The support system keeps the lateral branches fairly horizontal even under the weight of the raspberries. Next to each row of plants 110 there a lane 114. The polytunnel system 100 may set up to a particular specification to enable a robotic picking system to traverse each lane 114 and pick fruits from the rows of plants 110. An example specification 116 for raspberries is shown in Fig. 2. As can be seen, the specification 116 indicates various properties of the polytunnel system 100 including lane dimensions, lane terrain, crop, support system, and other aspects such as shading / blackout during harvesting. Robotic picking platform Referring to Fig. 3 a robotic picking platform is generally identified by reference numeral 200. The robotic picking platform 200 measures approximately 1.1 m x 1.45 m x 2.15 m (W x L x H) and has an unloaded mass (i.e. without picked fruit) of about 200 kg. The robotic picking platform 200 comprises a mobile base 202 on which is mounted a robotic picking system 204. Broadly, the mobile base 202 comprises a battery system (not shown), an electric motor system (not shown), driven wheels 206 that are rotated by the electric motor system to propel the mobile base 202, an autonomous navigation system (not shown), and a control system (not shown) for controlling the picking function (to be described in greater detail below). Steering and changing the orientation of the mobile base 202 may be achieved by rotating the driven wheels at different speeds and / or in opposite directions for example. The autonomous navigation system enables the robotic picking platform 200 to determine its location relative to the polytunnel system 100 and to navigate the lanes 114 picking fruit. Typical autonomous navigations systems that may be used in the robotic picking platform 200 may comprise positioning capabilities (such as GPS-RTK), obstacle sensors (such as LIDARs and 3D cameras), and navigation / control algorithms running on on-board computers. Examples of suitable mobile platforms in the market with such capabilities include Burro robot (available from Augean Robotics, US) and the Amiga robot (available from farm-ng, US)".. Generally, the autonomous navigation system may move the robotic picking platform 200 forward along a lane 114 in steps, pausing to pick fruit at each stop and from bushes on each side, before moving forward to the next picking position. Once the robotic picking platform 200 has filled the capacity of its onboard storage, an operator may remove trays of picked fruits or vegetables to allow the robotic picking platform 200 to carrying on working. An operator may also swap the batteries when they run low on charge. Robotic picking system The robotic picking system 204 comprises a plurality of linear actuators 208 which are oriented generally along the z-axis. In this example, four linear actuators 208 are illustrated but it is foreseen that other numbers of linear actuators 208 such as one, two, three, four, five, six or more could be used on a single mobile base 202. In some embodiments it may be that an even number of linear actuators is used in total, with half the total number along each side of the mobile base 202. Each linear actuator enables movement of a robotic arm 210 up and down the z-axis. The linear actuator may be of a length that enables each robotic arm 210 to move over substantially the full height of the crop within the polytunnel system 100. Accordingly, different height linear actuators 208 may be used on the mobile base 202 dependent on the crop to be picked. In this example, the range of travel of each robotic arm in the z-axis (from a position adjacent a top of the mobile base 202 to the upper end of the linear actuator 208) is 1.2 m, but it is foreseen that other ranges could be used depending on the fruit or vegetables to be picked. The height of the of the mobile base 202 is approximately 0.7 m, and so a picking height range of 0.7 - 2.0 m is provided, covering the max / min harvesting height range given in the specification 116 (see Fig. 2). It is noted that the max / min harvesting range could be changed to suit the growing facility. For example, fruits or vegetables could be grown between a range of heights above the ground that includes heights not easily reached by human pickers. The robotic picking system may be adapted to work over such an increased range, potentially facilitating greater yields of fruit or vegetables. The robotic picking system 200 may further comprise an onboard storage system 220 for storing picked fruit whilst other fruits are picked. The onboard storage system 220 may comprise a plurality of punnet crates 222 each holding a plurality of punnets 224, for example ten. Each punnet 224 is destined for the end-consumer. By picking and packing fruits directly from each robotic arm 210 into the punnet 224 to be purchased by the endconsumer the overall picking payload may be simplified. Although punnet crates 222 and punnets 224 are illustrated in this example, it is foreseen that the robotic picking system 200 may use other packing forms and systems as desired for the fruit / vegetable to be harvested, packaged and sent into the food distribution network. The robotic picking system 200 may further comprise a fruit or vegetable position detection system. In some embodiments the position detection system may comprise two parts: a first position detection system and a second position detection system. The first position detection system may utilise the frame of reference of the mobile base 202. The second position detection system may utilise the frame of reference of each robotic arm 210 respectively. The first position detection system may be adapted to inspect substantially the full height of the plants along a certain length of the row of plants 110 to identify potential fruit or vegetables which could be picked by the robotic picking system 204. This may be performed whilst the robotic picking platform 200 is stationary or whilst moving. A function of the position detection system may be to estimate the location in three dimensions (e.g. x-y-z frame of reference as indicated in Fig. 2) of the potential fruit or vegetables which could be picked. The robotic picking platform 200 may be adapted to analyse the information from the first position detection system to determine whether the fruit or vegetable is suitable to be picked, for example whether it is judged to be at a particular stage in the ripening process, meet certain size and colour requirements, whether it can be reached by the robotic picking system 204, etc. The robotic picking platform 200 may carry out this analysis locally (i.e. using computer(s) onboard the robotic picking platform 200) and / or may transmit relevant data to a remote computer for analysis. First position detection system The first position detection system may operate using one or more part of the electromagnetic spectrum to identify fruit(s) or vegetable(s) on the plant(s) adjacent the robotic picking platform 200 that may be harvested. In some embodiments the first detection system may comprise a first position sensor that has a field or angle of view. The first position detection system may detect fruits or vegetables to be picked that are within the field or angle of view of the first position sensor. In some embodiments the first position sensor may capture an image of the plant adjacent the robotic picking platform 200, in which the image comprises depth information (such as a range image). In some embodiments the first position sensor may comprise one or more image sensor. For example the first position sensor may comprise a 3D camera 226 such as a stereo camera, a structured light camera, a holographic camera, and a LIDAR, scanner. An example 3D camera that could be used is the Intel RealSense D435, an RGBD (RGB + NoIR stereo pair), which has high frame rate (>30fps), high resolution (1920pxl080p) and wide field of view (77 degree diagonal). A global shutter may also be used on with two position sensors, which improves position detection when objects are moving relative to the position sensor (e.g. if the fruit or vegetable is blown by the wind). In the example shown in Fig. 3, the first position sensor is a 3D camera 226. There may be one 3D camera 226 associated with each linear actuator 208. The robotic picking system 204 comprises a frame 228 supported on the mobile base 202. Each 3D camera 226 is mounted on the frame 228 so that it may image the full height of the plants adjacent each linear actuator 208 and approximately within the range of the respective robotic arm 210. Once the robotic picking platform 200 has selected a fruit or vegetable to be picked from the information obtained by the first position detection system, the robotic arm 210 is moved to a position proximate the fruit or vegetable to be picked. This may be on the basis of depth information in an image(s) obtained by the first position detection system. The second detection system may then be used to position a robotic arm 210 proximate the fruit or vegetable to be picked. This will be described in greater detail below. Robotic arm Referring again to Fig. 3 each robotic arm 210 comprises a first segment 212, a second segment 214 and an end-effector 215. The proximal end of the first segment 212 is attached to a respective linear actuator via a first revolute joint 216. An electric motor 216 enables the control system to rotate of the first segment 212 about the first revolute joint to position a distal end of the first segment 212 on an arc in the x-y plane. The proximal end of the second segment 214 is attached to the distal end of the first segment 212 via a second revolute joint 218. An electric motor inside the first segment 212 enables the control system to rotate of the second segment 214 about the second revolute joint to position a distal end of the first segment 212 on an arc in the x-y plane. The end-effector 215 is mounted on the distal end of the second segment 214. By controlling both the first and second electric motors the control system may position the end-effector in the x-y plane around the respective linear actuator 208. For example the end-effector 215 may be positioned at a picking position near a plant. By additionally controlling the position of the robotic arm 210 along the linear actuator 208, the control system may adjust the height of the end-effector 215 relative to the plants and fruit or vegetables to be picked and, once picked, move the end-effector 215 to a loading position adjacent a punnet 224 in the punnet crate 222. By controlling the linear actuator 208 and at least one of the first and second electric motors at the same time, the control system may move the end-effector 215 in more complicated movements in three dimensions. When fully extended, the length of each robotic arm 210 between the proximal end of the first segment 212 and the end-effector 215 may be approximately 0.6 m. Figs. 4A - 4C show one of the robotic arms 210 in greater detail. The end-effector 215 is generally similar in construction and function to that described in WO 2022 / 263456, the contents of which is incorporated herein for all purposes. In general, the end-effector 215 comprises a housing 230 of an approximately cup-like shape defining a generally circular opening 232 through which a fruit or vegetable to be picked may be moved and received within an internal volume 234 inside the housing 230. Within the housing 230, a membrane 236 of resilient material (e.g. silicone) is provided in a ring-like arrangement and which is adjustable between an uninflated condition and an inflated condition. The fruit or vegetable to be picked is moved into the internal volume 234 (see also Fig. 6A - C) within the housing when the membrane 234 is in an uninflated condition. The membrane 236 is then inflated to grip the fruit or vegetable after which it may be picked by further movement of the endeffector 215 and / or robotic arm 210 (to be described in greater detail below). Once picked, the membrane 234 may be deflated and the fruit or vegetable allowed to fall a small distance into a storage volume 244. Second position detection system The distal end of the second segment 214 of the robotic arm 210 may also comprise the aforementioned second position detection system for detecting a fruit or vegetable to be picked. The second position detection system may be used once the robotic arm 210 has been positioned using the first position detection system. For example, the second position detection system may be used to refine or correct the position of the end-effector 215 prior to picking. In some embodiments, the second position detection system may be used to confirm the quality of the fruit or vegetable before picking. The second position detection system may operate using one or more wavelengths in one or more part of the electromagnetic spectrum to identify fruit(s) or vegetable(s) on the plant(s) adjacent the robotic picking platform 200 that may be harvested, including the visible part and / or infra-red part. In some embodiments the second position detection system may comprise a second position sensor that has a field or angle of view. The second position detection system may detect the position of a fruit or vegetable to be picked that is within the field or angle of view of the first position sensor. In some embodiments the second position detection system may capture images of a single fruit or vegetable identified by the robotic picking platform 200 using the first position detection system. The images obtained by the second position detection system may comprise depth information to facilitate location of the end-effector 215 adjacent the fruit or vegetable to be picked. The second position detection system may comprise a pair of cameras 238 enabling the control system to determine a stereo image of the fruit or vegetable to be picked. For example each camera may comprise a Raspberry Pi Camera Module 3, which has a high resolution (4608px2592p), a high frame rate (30fps), a large field of view (120 degree diagonal) and a variable focus (50mm - infinity). The camera can also produce an HDR output which makes it useful for outdoor applications with direct sunlight. Each camera is mounted adjacent the distal end of a respective stalk 240.. In this way, each camera 238 is fixed in the frame of reference of the second segment 214 of the robotic arm 210. The cameras may be oriented so that the centre of their fields of view are at 90 degrees to each other radially (radial separation angle) and may have with a slight upwards angle of approximately 15-20 degrees (elevation angle). Other angles are envisaged although it is noted that separating the cameras by approximately 90 degrees radially may bring imageprocessing speed advantages and may provide an improved positioning function. For example the separation angle and / or the elevation angle may be organised so that the cameras are well positioned relative to the rest of the end-effector 215, and can see the fruit or vegetable without taking in too much ambient light from above etc. In some embodiments, the control system of the robotic picking system 204 may use data from the second position detection system to perform image-based visual servoing (IBVS) to correct the position (if needed) of the end-effector 215 after its initial positioning using data from the first detection system. For example, the control system may process image feeds from the cameras and put a 'box' around the target fruit or vegetable in both image feeds. The robotic arm 210 is then moved so that each box is centralised within each image frame left to right so the fruit or vegetable is positioned directly above the end-effector 215. The position of the boxes in the image feeds can then be adjusted vertically to the correct position. Referring to Fig. 4C the distance between each camera lens and the vertical axis of the grasping point / region may be approximately 100 mm, to work with the focal length of the camera. There is a volume of space 250 adjacent the distal end of the robotic arm 210. The purpose of the control system and second detection system may be to place a fruit or vegetable identified by the first position detection system within the volume of space 250. With reference to Fig. 4C the second position sensor (e.g. 3D cameras 238) may each have a field of view 252 and the second position sensor may be oriented so that a central axis 254 of the field of view 252 crosses the volume of space 250. Only one field of view 252 and central axis 254 is shown in Fig. 4C for clarity. End-effector configurations There is a volume of space 250 adjacent the distal end of the robotic arm 210. The second position detection system enables the control system to position the distal end of the robotic arm 210 so that this volume of space 250 contains a fruit of vegetable to be picked. The end-effector 215 is movably (e.g. rotatably, pivotably) mounted on the distal end of the second segment 214 in a way that permits it to move along a path or trajectory relative to the second segment 214 and the second position detection system between a first configuration and a second configuration. The volume 250 may lie on the path of the endeffector 215 so that a fruit of vegetable may be caught or captured by the end-effector 215 ready for picking. The Figures show the volume of space 250 as cylindrical. However, it is noted that this is not essential and the volume of space 250 can be considered of any shape suitable to contain a fruit or vegetable to be picked. Figs. 4A, 4B, 4C and 6B show the end-effector 215 in the second configuration. Fig. 6A shows the end-effector 215 in the first configuration. The end-effector 215 is configurable so that in the second configuration (e.g. Fig. 4B) the end-effector 215 is out of the way and cannot grasp a fruit or vegetable within the volume of space 250 at the distal end of the robotic arm 210. This may make it easier to correctly position the fruit or vegetable in the volume of space 250. Furthermore, in the second configuration the second position detection system has an improved view of the fruit or vegetable to be picked (which may improve locating the end-effector 215 near to the fruit). In the first configuration, the end-effector may grasp a fruit or vegetable within the volume of space 250, but at the same time may obscure or obstruct the view of the fruit or vegetable by the second position detection system. See Fig. 9A for example. In the first configuration the internal space 254 in the end-effector 215 may be substantially aligned with the volume of space 250, whereby the membrane 236 substantially surrounds the fruit or vegetable (see Fig. 9B). In the second configuration the end-effector 215 is substantially 'out of the way' of the second position detection system, the end-effector 215 may more accurately position the fruit or vegetable relative to the volume of space 250. Having done that, it may only be necessary move (e.g. rotate, translate) the end-effector 215 from the second configuration to the first configuration in which the fruit or vegetable to be picked is located within the internal volume 234. In other words, to 'catch' the fruit / vegetable in the end-effector 215 for picking, no further movement of the robotic arm 210 is needed either by the linear actuator 238 or by rotation of the first and second segments of the robotic arm 210. By making the end-effector moveable relative to the robotic arm 210 and the second position sensor it may be possible to increase the probability of'catching' the fruit or vegetable in the end-effector 215 on the first attempt. This may also help the second detection system and the control system to determine whether the fruit or vegetable has entered the volume 234 in the end-effector 215 successfully, or whether the fruit or vegetable might have been pushed upwards by the rim of the end-effector 215. Being able to tell if a fruit or vegetable is inside the end-effector 215 is important so that time is not wasted trying to pick a fruit or vegetable that is not inside the end-effector 215. Figs. 5A, 5B and 5C illustrate schematically some example paths 241 along which the endeffector 215 may move. In Fig. 5A, path 241 may be in the form of an arc. This corresponds to the movement of the end-effector 215 between the configurations shown in Fig. 6A and 6B for example. In another embodiment shown in Fig. 5B, the path 241 may substantially linear. In another embodiment shown in Fig. 5C, the path 241 may be non-linear, and may comprise substantially linear and non-linear sections. In the examples of Figs. 5A, 5B and 5C, movement of the end-effector 215 along the path 241 causes the internal volume 254 to move along the path 241, and to bring it into and out of alignment with the volume space 250 at the distal end of the robotic arm 210. By positioning the robotic arm 210 so that a fruit or vegetable lies on the path 241 of the end-effector 215, it is possible to 'catch' or 'capture' the fruit or vegetable in the internal volume 254 by moving the end-effector 215 relative to the robotic arm 210. The examples shown in Figs. 5A, 5B and 5C are purely illustrative and it is foreseen that other shapes of path 241 are possible. Field of view As described above the second position sensor has a field of view 252. In some embodiments in the second configuration the end-effector 215 may be substantially outside at least a portion of said field of view and in the first configuration at least a part of the endeffector 215 is within said portion of said field of view 252. In some embodiments, at least a part of the end-effector 215 may always remain within the field of 252 but move in and out of the portion. The at least a portion of the field of view 252 may comprises a region encompassing a centre of the field of view. The region may be a fraction of the entire field of view, or it may be substantially the entire field of view. In the latter case, the at least a part of the end-effector 215 may move into and out of the field of view 252 altogether between the first and second configurations. The at least a portion of the field of view may correspond to the volume of space 250. In some embodiments the at least a part of said end-effector may interrupt a line of sight between the second position detector and the volume of space 250 when in the first configuration. End-effector lid Referring to Figs. 5 and 6A - 6C, the end-effector 215 may further comprise a lid 242 which encloses the storage volume 244 beneath the membrane 236. The lid 242 may be moved between a closed position and an open position. In the closed position picked fruit or vegetables are retained in the storage volume 244 whilst further picking operations are completed and / or picked fruit / vegetables moved to the onboard storage system 220. In the open position (see Fig. 6C) the lid 242 has been moved away from the housing 230 to create a downwardly facing opening 246 through which the picked fruits / vegetables may be released from the storage volume 244 under gravity. The storage volume 244 may be of any suitable size to hold one, two, three, four or more fruits / vegetables at any one time. For example, the storage volume 244 may be sufficient hold between two to four raspberries. In some embodiments the lid 242 of the end-effector 215 may be adapted to move between the open position and the closed position, and vice-versa, once the end-effector 215 reaches one end of its range of motion relative to the second segment 214 of the robotic arm 210. For example, in the embodiment shown in Figs. 6B and 6C, the lid 242 is caused to open once the end-effector 215 reaches a maximum downward rotation point. Comparing Figs. 6B and 6C it is noted that the housing 230 of the end-effector 215 has not changed position, but the lid 242 has moved from a closed position to an open position. How this may be achieved is described in greater detail below. Fig. 7 shows an embodiment of the end-effector 215 and its relationship with some interior parts of the second segment 214 of the robotic arm 210. These interior parts facilitate the relative movement between the second segment 214 and the end-effector 215. An electric motor 250 (MAKE / MODEL?) is mounted within the second segment 214. The electric motor 250 may be a Pololu 4867. The electric motor 250 may comprise an encoder to enable accurate feedback of the position of the end-effector 215. The electric motor 250 may also comprise a magnet and hall effect sensor to provide end stop position sensing. In use, the electric motor drives a bevel gear 252 clockwise or anticlockwise. The end-effector 215 is rotatably mounted to the second segment 214 (mounting not shown in Fig. 7) so that it is rotatable under action of the electric motor 250 and bevel gear 252 about axis 254. As is apparent from Fig. 7 the lid 242 and housing 230 of the end-effector 215 are each rotatably mounted to the second segment 214 for rotation about axis 254. In some embodiments the end-effector 215 is adapted so that, within a given range of movement, the lid 242 and housing 230 rotate substantially in unison. In this way the lid may be kept closed and picked fruit or vegetables retained in the storage volume 244. The end-effector 215 may be further adapted so that the lid 242 continues rotating when the housing 230 has stopped rotating at one end of the range of movement. In this way the lid 242 can be opened / closed whilst the housing 230 remains stationary relative to the second segment 214 of the robotic arm 210. Fig. 8A illustrates an example of how such functionality may be achieved in some embodiments. The bevel gear 252 rotates a shaft 256 to drive a set of spur gears 256. The spur gears 256 comprise a first set of spur gears 256a, 256b that drive movement of the lid 242. A second set of spur gears 257a, 257b drive movement of the housing 230 of the endeffector 215. The spur gears 256a, 257a may be provided in two pairs, one at either end of 18 shaft 256. Each pair of spur gears 256a, 257a may be formed integrally and fixed to the shaft 256 or may be separate components fixed to the shaft 256. The spur gears 256a comprise teeth that cooperate with teeth of the spur gears 256b, and which drive the lid 242 through a range of motion of approximately 90 degrees. This range of motion can be seen by comparing Figs 8A, 8B and 8C. The spur gears 256a drive the lid 242 through a range of motion between a position in which the lid 242 is oriented approximately horizontally (Fig. 8A) to a position in which the lid 242 is oriented approximately vertically (Fig. 8C). Teeth 256c of spur gears 256a extend over an approximately similar angular range and do no extend fully around the circumference as it is not necessary to drive the lid 242 beyond the range shown in the Figures. In contrast, spur gears 257a comprise a toothed portion 257c and a toothless portion 257d both of which lie within the same (or a similar) angular range to the teeth 256c. The spur gears 257b comprise similar toothed and toothless portions. A function of toothed portion 257c and toothless portion 257d is to drive movement of the housing 230 through a first angular range and then not through second angular range whilst the lid 242 continues to be driven thereby opening the lid 242 on the housing 230. In some embodiments when the housing reaches the end of the first angular range it may reach a stop (not shown) against which its weight is held by the robotic arm 210. This functionality may be achieved under the action of the electric motor 250 by rotation of the bevel gear 252 in one direction to move the end-effector 215 down (toward the second configuration) and open the lid 242, and by driving the bevel gear 252 in the opposite direction to move the end-effector 215 up (toward the first configuration) and close the lid 242. Referring to Fig. 8A, it is noted that in this position both the first set of spur gears 256a, 256b and the second set of spur gears 257a, 257b have teeth engaged with one another. Referring to Fig. 8B, spur gears 256a and 257a have been rotated anticlockwise by the bevel gear 252, causing a corresponding clockwise rotation of the spur gears 256b, 257b. This has caused the same movement of both the housing 230 and lid 242, in unison. However, it is noted that the spur gear 257a has reached the end of the toothed portion 257c. Any further counterclockwise rotation of spur gear 257a will simply move the toothless portion 257d past the teeth of spur gear 257b and not cause any further movement of housing 230 (see Fig. 8C). A pin (not shown) and respective slots 258a and 258b (see Fig. 8B) in each of the housing 230 and lid 242 limit their range of motion. However, the teeth 256c of spur gear 256a remain engaged with the corresponding teeth of spur gear 256b. Further counterclockwise rotation of spur gear 256a will cause a corresponding movement of the lid 242 move it to the position shown in Fig. 8C in which picked fruit or vegetables can be released into a punnet or other container. When the spur gears 256a are driven in the opposite sense, the reverse movements occur happens. Firstly, the lid 242 is moved to the closed position whilst the housing 230 is not moved (Fig. 8C to 8B). Then the toothed portion 257c of spur gear 257a re-engages with the toothed portion of spur gear 257b. The housing 230 and lid 242 are then driven in unison back to the position show in Fig. 8A. In this way the control system of the robotic picking platform 200 may control each endeffector 215 using a single motor in each robotic arm 210 but achieve multiple functions of the end-effector 215. These functions may include moving each end-effector 215 between the second configuration and the first configuration, and then selectively opening the lid 242 to deposit picked fruit or vegetables. Picking operation Figs. 9A and 9B illustrate some of the configurations of the robotic arm 210 in use picking a fruit 300. In Fig. 9A the end-effector 215 is in the second configuration. The second position sensor (e.g. camera 238 on stalk 240) has a clear line of sight 302 to the fruit 300, and the control system is able to use data from the second position sensor to place the fruit within the volume of space 250 adjacent the distal end of the robotic arm 250. However, the endeffector 215 is not able to grasp the fruit 300 in the second configuration. In Fig. 9B the end-effector 215 is in the first configuration. The line of sight 302 of the second position sensor is obstructed by the end-effector 215, but the end-effector 215 may grasp the fruit 300 since it is now within the internal volume 254 of the end-effector 215. In this embodiment, the change between the first and second configurations is by movement of the end-effector 215 only. An advantage of this may be that the chance of 'catching' the fruit 300 in the end-effector is increased. Another advantage may be that the chance of the end-effector 215 and / or robotic arm 210 getting caught on the support system 112 (e.g. strings) around the plant is reduced. Overall, the combination of the first and second configurations may allow for more accurate positioning of the end-effector 215 with the fruit or vegetable to be picked within the volume of space 250, since the second position sensor has a substantially unobstructed view of the fruit or vegetable (with the end-effector 215 'out of the way'). More accurate positioning of the end-effector 215 may increase the chance of successfully catching the fruit or vegetable in the end-effector 215 and help to reduce overall picking time per fruit / vegetable. Furthermore, once in that position only a comparatively small movement of the end-effector 215 relative to the robotic arm 210 is needed to put the fruit or vegetable into the internal volume 254 of the end-effector 215. Using only small movement may reduce the chance of the end-effector 205 catching on the support system 112 of the plant during picking. In some embodiments it is envisaged that the second position sensor may also be moveable between the two configurations. For example, the second position sensor may be moved to maintain the view of the fruit or vegetable to be picked as long as possible (at least until the fruit or vegetable disappears inside the end-effector 215). Once the end-effector 215 has grasped the fruit or vegetable it may be possible to pick the fruit or vegetable by changing the end-effector 215 from the first configuration to the second configuration. Additionally, either at the same time or subsequently, it may be possible to move the robotic arm 210 both downward and outwards to effect more reliable picking. Although the embodiments above have been described in the context of picking fruit or vegetables, it is foreseen that at least some embodiments may have use for picking up objects more generally. For example, embodiments of the robotic arm described herein may find use in picking objects in warehouses, etc. For example some embodiments may find application in grocery warehouse automation where products of similar dimensional variability, ripeness etc are detected by a vision system that may perform better if the view of the cameras / sensors are not partially occluded or obscured during a specific stage of operation. Some embodiments may find application for picking fruit or vegetables in vertical farming systems. For example, the robotic arm may be mounted on and moveable in a vertical and / or horizontal rail system that is within or adjacent the vertical farming system. In some embodiments the robotic arm may be used in fruit or vegetable sorting facilities. It is also foreseen that the end-effector of the robotic arm may be moveable along paths or trajectories having other orientations than described above. For example, it may be desirable in some embodiments for the end-effector to be rotatable about the longitudinal axis of the robotic arm. This may be useful for capturing fruit or vegetables in the endeffector that are judged to have a shape or growing orientation that may have some sideways component. In some embodiments it may be desirable to orient the end-effector so that it is moveable from a position above an object to be picked. The grasping mechanism of the end-effector is also not limited to the embodiments described above that use an inflatable membrane. It is foreseen that the end-effector may utilise other grasping mechanisms such as a parallel jaw having a grasp point, a suction cup, or any end-effector that needs to locate an object within or on a volume of space adjacent the end-effector before the object can be grasped. The skilled person will recognise that many further modifications of the described embodiments are possible, without departing from the scope of the invention as defined in the appended claims.

Claims

1. A robotic arm for picking fruit or vegetables from a plant, which robotic arm comprises a proximal end for attachment to a robotic picking platform and a distal end for positioning adjacent a fruit or vegetable to be picked, which distal end comprises:an end-effector adapted to pick a fruit or vegetable from a volume adjacent said distal end; anda position sensor for facilitating detection of the position of the fruit or vegetable relative to the volume at the distal end;wherein said position sensor and said end-effector are configurable by relative movement between said position sensor and said end-effector into a first configuration in which operation of the end-effector would grasp a fruit or vegetable within said volume and a second configuration in which operation of the end-effector would not grasp a fruit or vegetable within said volume.

2. A robotic arm as claimed in claim 1, the arrangement being such that in said second configuration a view of the fruit or vegetable by said position sensor is substantially uninhibited by said end-effector and in said first configuration said view is at least partly inhibited.

3. A robotic arm as claimed in claim 1 or 2, wherein said position sensor has a field of view, the arrangement being such that in said second configuration the end-effector is substantially outside at least a portion of said field of view and in said first configuration at least a part of the end-effector is within said portion of said field of view.

4. A robotic arm as claimed in claim 3, wherein said at least a portion of the field of view comprises a region encompassing a centre of the field of view, a fraction of the entire field of view, or substantially the entire field of view.

5. A robotic arm as claimed in claim 3 or 4, wherein in said second configuration said at least a part of the end-effector is visible within a periphery of said field of view.

6. A robotic arm as claimed in any preceding claim, wherein in use when the distal end of the robotic arm is positioned adjacent the fruit or vegetable to be picked there is a line of sight between said position sensor and said fruit or vegetable, and said at least a part of said end-effector interrupts said line of sight when in said first configuration.

7. A robotic arm as claimed in any preceding claim, wherein said end-effector is moveable independently of said position sensor.

8. A robotic arm as claimed in any preceding claim, wherein said position sensor is fixed relative to said robotic arm and said end-effector is moveable relative to said position sensor.

9. A robotic arm as claimed in any preceding claim, wherein said end-effector comprises a housing defining an internal volume into which the fruit or vegetable is to be received.

10. A robotic arm as claimed in claim 9, wherein in use, when said fruit or vegetable to be picked is located within said volume adjacent the distal end of the robotic arm, movement of the end-effector from the second configuration to the first configuration puts said fruit or vegetable within said internal volume of said end-effector.

11. A robotic arm as claimed in claim 9 or 10, wherein in use, when the fruit or vegetable to be picked is received in said internal volume, the housing obscures the view by the position sensor of the fruit or vegetable.

12. A robotic arm as claimed in claim 9, 10 or 11, wherein said end-effector further comprises a flexible membrane within the internal volume, the membrane defining an aperture and an inflatable volume, and the membrane being configurable to increase the inflatable volume from an uninflated configuration to an inflated grasping configuration to thereby narrow the aperture and permit the fruit or vegetable within the internal volume to be grasped.

13. A robotic arm as claimed in any preceding claim, wherein said end-effector further comprises a storage volume for temporary storage of at least one fruit or vegetable after picking.

14. A robotic arm as claimed in claim 13, wherein said storage volume is arranged to catch said at least one fruit or vegetable as it falls under gravity after picking.

15. A robotic arm as claimed in claim 13 or 14, further comprising a lid that is openable to release said at least one fruit or vegetable from the storage volume, and that is closeable thereafter.

16. A robotic arm as claimed in claim 15, wherein said lid is openable when said endeffector and said position sensor are in said second configuration.

17. A robotic arm as claimed in claim 15 or 16, further comprising an actuator for moving said end-effector between said first and second configurations and for opening and closing said lid.

18. A robotic arm as claimed in claim 17, wherein said actuator comprises a single actuator and wherein operation of said actuator in a first direction causes said end-effector to move from said first configuration to said second configuration and then to open said lid whilst a housing of said end-effector remains stationary, and operation of said actuator in a second direction opposite to said first direction causes lid to close whilst said housing23remains stationary, and then said end-effector to move from said second configuration to said first configuration.

19. A robotic arm as claimed in claim 18, further comprising a mechanism for disengaging said housing from said actuator at said first configuration when said actuator operates in said first direction, and for re-engaging said housing to said actuator at said first configuration when said actuator operates in said second direction.

20. A robotic arm as claimed in claim 21, wherein said mechanism comprises a gear comprising a toothed and toothless portion.

21. A robotic arm as claimed in any preceding claim, wherein said position sensor comprises an image sensor, and optionally wherein depth data is obtainable from an output provided by said image sensor.

22. A robotic arm as claimed in claim 21, wherein said image sensor provides an output signal representing detection of a visible and / or a non-visible wavelength of the electromagnetic spectrum.

23. A robotic arm as claimed in claim 21 or 22, wherein said image sensor comprises at least two image sensors adapted to provide an output suitable for generating a computer-processable stereoscopic image, and optionally wherein said at least two image sensors are oriented so that the view of one image sensor at least partly overlaps with the view of the other, and each image sensor is oriented toward said volume adjacent the end of the distal end of the robotic arm.

24. A robotic arm as claimed in any preceding claim, wherein said movement between said first configuration and said second configuration comprises at least one of a rotation movement, a non-linear movement and a linear movement.

25. A robotic arm as claimed in any preceding claim, wherein said end-effector is moveable relative to said robotic arm along a path between said first configuration and said second configuration, said path crossing or containing said volume adjacent the distal end of said robotic arm, the arrangement being such that, in use, said fruit or vegetable may be positioned within said volume on said path and movement of said end-effector from said second configuration to said first configuration along said path captures the fruit or vegetable.

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