End-of-arm suction gripper

Abstract

Title: End-of-arm suction gripper Abstract The disclosure relates to an end-of-arm suction gripper for gripping an object from a pile of objects held by a container. The suction gripper comprises a frame carrying an array of suction cups that defines a planar quadrilateral gripping face for being brought in engagement With the object. The array of suction cups includes a staggered subarray Where the suction cups are arranged in rows that are staggered With respect to each other to form a triangular pattern. The staggered subarray forms an acute angled vertex of the gripping face.

Description

P 137298NL00 Title: End-of-arm suction gripper FIELD The disclosure relates to end-of-arm suction grippers for gripping objects. BACKGROUND End-of-arm suction grippers typically serve as the interface between a robotic arm and an object. Suction grippers utilize negative pressure to grip objects, making them versatile and efcient for handling various shapes, sizes, and materials. Suction grippers generally include an array of suction cups connected to avacuum source. These suction cups, typically made from exible materials like rubber or silicone, adhere to the objects surface When air is evacuatedfrom Within the cups, creating a vacuum seal. The array conguration allows for the distribution ofgripping force across multiple points, enhancing stability and grip on larger or irregularly shaped objects. A challenge associated With using suction grippers for end-of-arm tooling is the difculty in gripping objects of different shapes and sizes from a chaotic pile, for example When dealing parcels. In such situations, the objects are often stacked orjumbled together Within a three-sided container, creating an irregular and unstable pile. This disordered arrangement can result in partial or obstructed surfaces, making it challenging for the suction gripper to achieve a secure vacuum seal on individual items. The variability in object positioning and surface exposure Within the pile exacerbates this problem, leading to unreliable grip performance and potentially causing inefciencies or failures in automated handling processes. SUMMARY It is an object to propose a suction gripper for gripping objects from a pile of objects. In a more general sense it is an object to overcome or reduce at least one ofthe disadvantages ofthe prior art. It is also an object to provide alternative solutions which are less cumbersome in assembly and operation and which moreover can be made relatively inexpensively. Alternatively it is an object to at least provide a useful alternative. Hereto, an aspect provides an end-of-arm suction gripper for gripping an object from a pile of objects held by a container. The suction gripper comprises a frame carrying an array ofsuction cups that denes a planar gripping face for being brought in engagement with the object. The array of suction cups includes a staggered subarray where the suction cups are arranged in rows that are staggered with respect to each other to form a triangular pattern. The staggered subarray forms an acute angled vertex of the gripping face. The pointed configuration provided by the acute angled vertex allows the gripper to penetrate into tight spaces and corners ofthe container that are typically difficult to reach with conventional gripper designs. This improves the grippers overall maneuverability and efcacy in handling objects from the pile, particularly those constrained within three- sided containers. By distributing the suction cups ofthe subarray in a staggered manner, the gripper maximizes contact points at the triangular pattern, allowing for a more uniform distribution of suction force. Optionally, the array ofsuction cups denes a substantially quadrilateral-shaped gripping face. The quadrilateral shape is found to be particularly advantageous in navigating and operating within the connes ofthe container. With the acute angled vertex and straight edges ofthe quadrilateral gripping face allow the gripper to approach and align more effectively with objects located near the sides and corners ofthe container. This geometric versatility ensures that the suction gripper can access and securely lift objects even when they are positioned at the edges or in corners. Optionally, the array ofsuction cups forms an asymmetrically shaped gripping face. The gripping face may hence lack a symmetry axis. The varied contour ofthe gripping face enables selective engagement with objects, providing exibility to grip objects from different angles and orientations. Optionally, the array ofsuction cups includes a non-staggered subarray where the suction cups are arranged in rows that are non- staggered with respect to each other to form a square or rectangular pattern, and wherein the non-staggered subarray forms a straight angled vertex ofthe gripping face. The straight-angled vertex offers an efcient way to engage with objects positioned along the sides or at the bottom ofa container. The linear arrangement of suction cups along the edge ofthe vertex provides a continuous line of suction, effective for creating a strong seal on objects that are stacked or tightly packed against the container walls. Furthermore, the combination ofboth staggered and non-staggered subarrays allows for a versatile gripping face that can adapt to various object shapes and packing arrangements. The non-staggered subarrays square or rectangular pattern complements the triangular staggered subarray for handling both irregular and regularly shaped items efficiently. Optionally, the gripping face includes an obtuse angled vertex. The obtuse angled vertex is advantageous for accessing objects located towards the middle of a chaotic pile. The combination ofan acute-angled, right- angled and obtuse-angled vertices within the same gripping face particularly provides a versatile tool capable ofadapting to various object shapes and pile configurations. Optionally, the obtuse angled vertex is formed at an interface between the staggered and the non-staggered subarrays. Optionally, the frame is shaped such that a planar outline ofthe frame, parallel to the planar gripping face, substantially resembles a shape ofthe gripping face formed by the array of suction cups.Aframe that mirrors the gripping face shape facilitates smoother and more precise maneuverability ofthe gripper within confined spaces, such as containers with chaotic piles of objects. The matching shapes enable the gripper to navigate tight corners and complex arrangements more effectively. Optionally, the planar outline ofthe frame in a plane parallel to the planar gripping face defines a quadrilateral. Optionally, the planar outline ofthe frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose an acute angled vertex. Optionally, the planar outline ofthe frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose an obtuse angled vertex. Optionally, the planar outline ofthe frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose a straight angled vertex. Optionally, the planar outline ofthe frame in a plane parallel to the planar gripping face defines a quadrilateral, particular a convex quadrilateral. Optionally, the array ofsuction cups is divided into a plurality of independently controllable suction zones, each suction zone including a one or more suctions cups ofthe array. Optionally, the staggered subarray is subdivided into at least two independently controllable suction zones. Optionally, a suction zone ofsaid at least two suction zones is formedby a single row ofsuction cups that includes a suction cup positioned at the acute angled vertex and extends linearly along an outer edge ofthe staggered subarray. The suction zone that extends along the outer edge of the staggered subarray is particularly advantageous for gripping objects located in the corners ofthe container. The acute angled vertex allows the gripper to penetrate tight spaces, while the outer edge row provides a continuous straight line of suction, ensuring a secure grip on objects positioned against container walls or in corners. Optionally, the plurality ofindependently controllable suction zones includes a suction zone having a non-staggered subarray ofN byM suction cups arranged in a square or rectangular pattern, withN andM being non-zero integer numbers. It will be appreciated thatN andMmay be equal to each other for forming a square pattern, or different from each other for forming a rectangular pattern. Optionally, the plurality ofindependently controllable suction zones includes four square or rectangular suction zones so arranged relative to each other to jointly form a non-staggered square or rectangular pattern of2N by2M suction cups. Optionally, the non-staggered square or rectangular pattern of2N by2M suction cups forms a right angled vertex ofthe planar gripper face. Optionally, the gripping face is a rst gripping face and wherein the frame carries a further array ofsuction cups that denes a second planar gripping face that extends non-parallel, particularly transverse, to the first gripping face. In environments where objects are arranged in complex or overlapping congurations, the ability to grip from different angles enhances the extraction process. The suction gripper can selectively use the most appropriate gripping face based on the objects position and orientation. Optionally, the further array of suction cups is formedby a single row of suction cups that extends parallel to the first planar gripper face. The parallel row of suction cups is particularly advantageous for handling at or thin objects. The narrow conguration allows for precise alignment and secure gripping along the container walls. Optionally, the single row of suction cups extends along an edge of the first gripper face. Optionally, the further array of suction cups includes an extendable suction cup being extendably drivable relative to the frame in an extension direction parallel to the rst planar gripping face to an extended position in which the extendable suction cup extends beyond a planar outline ofthe first planar gripping face. The extendable suction cup can reach beyond the main gripping face, allowing the gripper to access objects located deeper within a pile or positioned in hard-to-reach areas. This extended reach is particularly advantageous for handling items at the back of a container or in tight, conned spaces where the primary gripping face cannot easily fit. Optionally, the extension direction is generally parallel to a tapering direction ofthe acute angled vertex. Another aspect provides a system. The system comprises a container for holding a pile of objects, the container comprising a bottom, at least one open side and an open top; and a suction gripper as described herein for gripping an object from the pile of objects. The containermay for example be three-walled container, such as a roll-cage container, having three sides closedby a side wall andhaving one open side. The objects held by the containermay hence be approached by the suction gripper from above through the open top as well as laterally from the open side. Optionally, the system comprises a computer-vision device, congured for determining a spatial orientation ofvisible the objects in the pile ofobjects relative to one another, selecting the object being at a top of the pile from the pile of objects, and determining an accessible grip face of the object for being grippedby the suction gripper. Another aspect provides a method ofgripping an object from a pile of objects heldby a container using a suction gripper as described herein. The method comprises, using a computer-vision device, determine a spatial orientation ofvisible the objects in the pile of objects relative to one another, selecting the object being at a top ofthe pile from the pile of objects, and determining an accessible grip face ofthe object for being gripped by the suction gripper. Optionally, the method comprises selecting a suction zone of a plurality ofindependently controllable suction zones ofthe suction gripper, and positioning the suction gripper so as to bring the selected suction zone in gripping engagement with the grip face ofthe object. It will be appreciated that any ofthe aspects, features and options described herein can be combined. It will particularly be appreciated that any ofthe aspects, features and options described in view ofthe suction gripper apply equally to the system and method, and vice versa. BRIEF DESCRIPTION OFTHE DRAWINGS Embodiments of the present invention will now be described in detail with reference to the accompanying drawings in which: Figures 1 and 2 show an example ofa suction gripper; Figures 3A and 3B show a suction gripper mounted to a robotic arm; Figure 4 shows a system, including a suction gripper and robotic arm; Figures 5A-5D show examples of disorderly piled objects held by a roll-cage container; Figures 6A and 6B show a suction gripper gripping a selected object from a disordered pile of objects; Figures 7A7D show another example ofa gripper. DETAILED DESCRIPTION Figure 1 shows an example of a suction gripper 100. The suction gripper 100 is congured for being mounted to a robotic arm 5 for gripping an object from a pile of objects heldby a container 40. The suction gripper 100 comprising a frame 10. The frame 10 carries an array ofsuction cups 20. The suction cups may be connected to a vacuum source, e.g. connected via the robotic arm 5, and provide a vacuum engagement with the object. The suction cups may ofthe bellows-type, including a exible, accordion-like structure allowing for better adaptability to curved and irregular surfaces. The array of suction cups 20 defines a planar gripping face 1 1 for being brought in engagement with the object. Here the planar gripping face 1 1 extends in the plane ofthe drawing. The array of suction cups 20 includes a staggered subarray of suction cups 2 1. The suction cups ofthe staggered subarray 21 are arranged in rows that are staggered with respect to each other. The suction cups ofthe staggered subarray 2 1 are arranged in a triangular pattern to form an acute angled vertex ofthe gripping face 1 1. The staggered subarray 21 in this example includes six suction cups, arranged in respective staggered rows ofthree, two and one suction cup. The gripping face 1 1 formedby the array ofsuction cups 20 is in this example substantially quadrilateral-shaped. It has four straight edges and four vertices. The staggered subarray 2 1 forms an acute angled vertex ofthe quadrilateral. Here, the quadrilateral further includes a straight angled vertex. Also, here, the quadrilateral includes an obtuse angled vertex. Also, here, the quadrilateral includes a further acute angled vertex. The quadrilateral lacks an axis ofsymmetry. The array of suction cups 20 also includes a non-staggered subarray ofsuction cups 22. The suction cups ofthe non-staggered subarray 22 are arranged in rows that are non-staggered with respect to each other. The non-staggered subarray 22 forms a square and / or rectangular pattern. The straight angled vertex is formed by the non-staggered subarray of suction cups 22. Here, the non-staggered subarray 22 includes eighteen suction cups.A part ofthe non-staggered subarray 22 includes a four-by- four arrangement ofsuction cups, forming a square pattern of suction cups. Another part ofthe non-staggered subarray 22 includes a two-by-one pattern of suction cups. The two-by-one pattern borders the four-by-four pattern in a pattern conforming way. Here, the suction cups two-by-one pattern can be considered to be appended to the bottom two rows ofthe square four-by-four pattern, effectively extending the bottom two rows by one suction cup. The further acute angled vertex ofthe quadrilateral is formed by the non-staggered array. The obtuse angled vertex ofthe quadrilateral is formed at the transition between the non-staggered subarray 22 and the staggered subarray. The frame 10 has in this example a plate-like body that extends in a plane parallel to the planar gripping face 1 1. The frame 10 has a quadrilateral-shaped outline in the plane parallel to the gripping face 1 1, particularly such that the planar outline ofthe frame 10, parallel to the planar gripping face 1 1, substantially resembles the shape ofthe gripping face 11 formed by the array of suction cups 20. Hence, the frame 10 conforms to the shape ofthe gripping face 1 1, to together dene the quadrilateral shape. Figure 2 shows the suction gripper 100 offigure 1 provided with an exemplary division into a plurality ofindependently controllable suction zones. In this example, the suction zones are non-overlapping. Each suction zone includes a two, three, or four suctions cups ofthe array in this example. It will be appreciated that figure 2 shows a particular example ofa division into suction zones but that other divisions are also envisioned. The staggered subarray 21 is subdivided into at least two independently controllable suction zones. One ofthe two suction zones is formedby a single row ofsuction cups that includes a suction cup positioned at the acute angled vertex and extends linearly along an outer edge ofthe staggered subarray 21. Another one ofthe two suction zones includes the remainder, here three, ofthe suction cups ofthe staggered subarray 2 1. The non-staggered subarray 22 is in this example divided into ve non-overlapping suction zones; four two-by-two suction zones and one two- by-one suction zone. This exemplary division ofsuction zones, in combination with the quadrilateral shape ofthe gripping face 1 1, provides great adaptability to different object shapes and sizes. Figures 3A and 3B show two perspective views ofthe suction gripper 100 at an end ofthe robotic arm 5. The connection to the robotic arm 5 is omitted in figure 3B. Figure 4 shows a system, comprising the suction gripper 100 of figures 1 and 2 mounted to a distal end ofthe robotic arm 5. The suction gripper 100 is accordingly an end-of-arm tool for the robotic arm 5. The robotic arm 5 maneuvers the suction gripper 100 relative to the container 40, and actuates one or more ofthe suction cups, e.g. one or more ofthe suction zones, appropriate for gripping an object heldby the container 40. The container 40 holds a pile of objects, here being parcels. The container 40 is in this example a roll-cage container 40 as commonly used for holding parcels. The objects have different shapes, sizes and structures, and are piled in a disordered manner. The assembly ofthe robotic arm 5 and the suction gripper 100 is in this example configured for picking the objects from the disorderly pile and place them onto a conveyor for successive processing. Figures 5A-5D show examples of disorderly piled objects held by a roll-cage container 40. The container 40 includes a bottom onto which the pile rests, here provided with wheels 44 to facilitate displacement. The container 40 has an open top 41 for being accessed by the suction gripper 100. The container 40 further has three closed side 43 extending vertically between the bottom and the open top 41, and one open side 42. The open side 42 ofthe container 40 faces the robotic arm 5. The open side 42 increases the accessibility to the objects ofthe pile by the suction gripper 100. The container 40 may alternatively have four closed sized and be only accessible through the open top 41. Figures 6A and 6B show an exemplary situation where the suction gripper 100 grips a selected object 1 to grip from the pile. The object 1 in this example has an exposed triangular face 2. The system is configured scanning the top side ofthe pile and distinguish different parcels from each other that have an exposed face. An orientation ofan exposed face 2 ofthe particularly object 1 can be determined. Based on the determined orientation ofthe exposed face 2 in relation to the other objects and the container 40 wall, an orientation ofthe suction gripper 100 may be determined for approaching and engaging the object 1 with its gripping face 1 1. One or more suction zones may be selected for being activatedvacuum gripping engagement with the object 1. In this example, the exposed face 2 ofthe object 1 is triangular shaped, substantially partially corresponding to the shape ofthe staggered subarray 2 1 ofsuction cups 2 1. Hence, here, the suction gripper 100 is positioned relative to the exposed object face such that the two suction zones ofthe staggered subarray 2 1 are activated and grip the object. None ofthe other suction zones are activated, to prevent additionally gripping any adjacent object. Figures 7A7D show examples ofthe suction gripper 100 ofthe preceding figures, wherein the frame 10 furthermore carries a further array of suction cups 30 that defines a further planar gripping face 12 that extends non-parallel, here transverse, to the gripping face 1 1. In these examples, the further array 30 includes a single row of suction cups. Figures 7A7C show an example where the further array 30 is a single array offour suction cups that extends transverse to a pointing direction ofthe acute angled vertex. More particular, each ofthe suction cups ofthe further array 30 is selectively extendable. Figure 7A shows each ofthe suction cups ofthe further array 30 being in a retracted state. Figure 7C shows each ofthe suction cups ofthe further array 30 being in an extended state. In the extended state, each ofthe suction cups ofthe further array 30 extends beyond the acute angled vertex. Figure 7B shows three suction cups ofthe further array 30 being in their retracted states, and one ofthe suction cups ofthe further array 30 in its extended state. As illustrated in figure 7B, the extended suction cup extends beyond the acute angled vertex to reach for small object in a corner ofthe container 40. Figure 7D shows an example where the further array 30 is a single row of suction cups that extends along an edge ofthe quadrilateral shaped gripping face 1 1, here including six suction cups. In this example the suction cups are non-extendable, but theymay alternatively be extendable. Herein, the invention is described with reference to specic examples ofembodiments ofthe invention. It will, however, be evident that various modications and changes may be made therein, without departing from the essence ofthe invention. For the purpose ofclarity and a concise description features are described herein as part ofthe same or separate embodiments, however, alternative embodiments having combinations of all or some ofthe features described in these separate embodiments are also envisaged. However, other modifications, variations, and alternatives are also possible. The specications, drawings and examples are, accordingly, to be regarded in an illustrative sense rather than in a restrictive sense. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word comprising does not exclude the presence ofother features or steps than those listed in a claim. Furthermore, the words a and an shall not be construed as limited to only one, but instead are used to mean at least one, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination ofthese measures cannot be used to an advantage.

Claims

1. An end-of-arm suction gripper for grasping an object from a a stack of objects held by a holder, where the suction gripper a frame includes that carries a series of suction cups that define a gripping surface to in to be brought into contact with the object; where the series of suction cups is a staggered subseries includes, in which the suction cups in staggered rows are arranged to form a triangular pattern, and where the staggered subseries forms an acute vertex of the gripping plane.

2. The suction gripper according to claim 1, where the series of suction cups defines a substantially quadrilateral gripping surface.

3. The suction grabber according to claim 1 or 2, where the series suction cups form an asymmetrical gripping surface.

4. The suction grabber according to one of the preceding claims, whereby the series of suction cups comprises a non-offset subseries, in which the suction cups arranged in unstaggered rows be to form a square or rectangular pattern, and where the non- staggered subseries forms a straight vertex of the gripping plane.

5. The suction grabber according to one of the preceding claims, whereby the gripping surface comprises an obtuse vertex.

6. The suction gripper according to conclusion 5, where the obtuse vertex is formed at a boundary between the staggered and the non-staggered subseries 7. The suction grabber according to one of the preceding claims, whereby the frame is shaped such that the planar perimeter of the frame, parallel to the flat gripping surface, essentially corresponds to the shape of the gripping surface formed by the series of suction cups.

8. The suction gripper according to claim 7, where the planar perimeter of the frame, parallel to the flat gripping surface, at least two substantially includes straight edges that enclose an acute vertex.

9. The suction gripper according to claim 7 or 8, where the planar perimeter of the frame, parallel to the flat gripping surface, at least two in essentially comprises straight edges that enclose an obtuse vertex.

10. The suction grabber according to one of claims 7 - 9, whereby the planar perimeter of the frame, parallel to the flat gripping surface, at least comprises two substantially straight edges that enclose a straight vertex.

11. The suction grabber according to one of claims 7 - 10, whereby the planar perimeter of the frame, parallel to the flat gripping surface, a defines a quadrilateral, in particular a convex quadrilateral.

12. The suction grabber according to one of the preceding claims, whereby the The series of suction cups is divided into a multitude of independently adjustable suction zones, where each suction zone has one or more suction cups from the series includes 13. The suction grabber according to claim 12, where the staggered subseries is subdivided into at least two independently controllable suction zones.

14. The suction grabber according to claim 13, where a suction zone of the the aforementioned at least two suction zones are formed by a single row suction cups comprising a suction cup positioned at the sharp vertex and extends linearly along an outer edge of the staggered subseries.

15. The suction grab according to one of the claims 12 14, whereby the multitude of independently adjustable suction zones a suction zone comprises with a non-stepped subseries of N at M suction cups, arranged in a square or rectangular pattern, where N and M are integers greater than be zero.

16. The suction grabber according to conclusion 15, where the multiplicityof independently adjustable suction zones four square or rectangular suction zones includes which are arranged in relation to one another in such a way that they together a non-staggered square or rectangular pattern of 2N by 2M form suction cups 17. The suction grabber according to claim 16, where the non-offset square or rectangular pattern of 2N by 2M suction cups a right angle forms of the flat gripping surface.

18. The suction grabber according to one of the preceding claims, whereby the gripping surface is a first gripping surface and the frame a further series of suction cups bears which defines a second gripping plane that is not parallel to, and in the particularly perpendicular to the first gripping surface.

19. The suction grabber according to claim 18, whereby the further series suction cups is formed by a single row of suction cups parallel extends to the first surface of grip.

20. The suction grabber according to claim 19, where the single row suction cups extends along an edge of the first gripping surface. 2 1. The suction grabber according to one of the claims 18 20, whereby the further series of suction cups includes an extendable suction cup that relative to is driveable extendable from the frame in an extension direction parallel to at the first gripping surface, to a deferral position in which the deferable suction cup extends beyond the flat perimeter of the first gripping surface.

22. The suction gripper according to claim 2 1, where the direction of deferral in the main feature is parallel to a tapering direction of the acute vertex.

23. A system comprising: a holder for holding a stack of objects, the holder comprising a bottom, at least one open side and an open top; and a suction grabber according to one of the preceding conclusions for the grabbing an object from the stack of objects.

24. A method for grasping an object from a by a holder held stack of objects with a suction gripper according to one of the conclusions 1 22, comprising, determining with a computer vision device a spatial orientation of visible objects in the stack of objects relative to each other, selecting the object that is on top of the stack is located within the stack of objects, and determining an accessible interface of the object to be grasped by the suction gripper.

25. The method according to claim 24, comprising selecting a suction zone of a multitude of independently adjustable suction zones of the suction gripper, and positioning the suction gripper such that the selected suction zone in connection with the surface of engagement of the object is brought. 1 / 7 100 11 21 10 20 22 5 FIG 1

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