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

[0001] P137298PC00

[0002] Title: End-of-arm suction gripper

[0003] FIELD

[0004] The disclosure relates to end-of-arm suction grippers for gripping objects.

[0005] BACKGROUND

[0006] 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 efficient for handling various shapes, sizes, and materials. Suction grippers generally include an array of suction cups connected to a vacuum source. These suction cups, typically made from flexible materials like rubber or silicone, adhere to the object’s surface when air is evacuated from within the cups, creating a vacuum seal. The array configuration allows for the distribution of gripping force across multiple points, enhancing stability and grip on larger or irregularly shaped objects.

[0007] A challenge associated with using suction grippers for end-of-arm tooling is the difficulty 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 or jumbled 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 inefficiencies or failures in automated handling processes. SUMMARY

[0008] 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 of the disadvantages of the 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.

[0009] 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 of suction cups that defines 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 of the container that are typically difficult to reach with conventional gripper designs. This improves the gripper’s overall maneuverability and efficacy in handling objects from the pile, particularly those constrained within three- sided containers. By distributing the suction cups of the subarray in a staggered manner, the gripper maximizes contact points at the triangular pattern, allowing for a more uniform distribution of suction force.

[0010] Optionally, the array of suction cups defines a substantially quadrilateral-shaped gripping face. The quadrilateral shape is found to be particularly advantageous in navigating and operating within the confines of the container. With the acute angled vertex and straight edges of the quadrilateral gripping face allow the gripper to approach and align more effectively with objects located near the sides and corners of the 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 of suction cups forms an asymmetrically shaped gripping face. The gripping face may hence lack a symmetry axis. The varied contour of the gripping face enables selective engagement with objects, providing flexibility to grip objects from different angles and orientations.

[0011] Optionally, the array of suction cups includes a non-staggered subarray where the suction cups are arranged in rows that are nonstaggered with respect to each other to form a square or rectangular pattern, and wherein the non-staggered subarray forms a straight angled vertex of the gripping face. The straight-angled vertex offers an efficient way to engage with objects positioned along the sides or at the bottom of a container. The linear arrangement of suction cups along the edge of the 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 of both staggered and non-staggered subarrays allows for a versatile gripping face that can adapt to various object shapes and packing arrangements. The non-staggered subarray’s square or rectangular pattern complements the triangular staggered subarray for handling both irregular and regularly shaped items efficiently.

[0012] 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 of an acute-angled, right- angled and obtuse-angled vertices within the same gripping face particularly provides a versatile tool capable of adapting to various object shapes and pile configurations.

[0013] Optionally, the obtuse angled vertex is formed at an interface between the staggered and the non-staggered subarrays.

[0014] Optionally, the frame is shaped such that a planar outline of the frame, parallel to the planar gripping face, substantially resembles a shape of the gripping face formed by the array of suction cups. A frame that mirrors the gripping face shape facilitates smoother and more precise maneuverability of the 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.

[0015] Optionally, the planar outline of the frame in a plane parallel to the planar gripping face defines a quadrilateral.

[0016] Optionally, the planar outline of the frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose an acute angled vertex.

[0017] Optionally, the planar outline of the frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose an obtuse angled vertex.

[0018] Optionally, the planar outline of the frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose a straight angled vertex.

[0019] Optionally, the planar outline of the frame in a plane parallel to the planar gripping face defines a quadrilateral, particular a convex quadrilateral.

[0020] Optionally, the array of suction cups is divided into a plurality of independently controllable suction zones, each suction zone including a one or more suctions cups of the array.

[0021] Optionally, the staggered subarray is subdivided into at least two independently controllable suction zones.

[0022] Optionally, a suction zone of said at least two suction zones is formed by a single row of suction cups that includes a suction cup positioned at the acute angled vertex and extends linearly along an outer edge of the 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 of the 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.

[0023] Optionally, the plurality of independently controllable suction zones includes a suction zone having a non-staggered subarray of N by M suction cups arranged in a square or rectangular pattern, with N and M being non-zero integer numbers. It will be appreciated that N and M may be equal to each other for forming a square pattern, or different from each other for forming a rectangular pattern.

[0024] Optionally, the plurality of independently 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 of 2N by 2M suction cups.

[0025] Optionally, the non-staggered square or rectangular pattern of 2N by 2M suction cups forms a right angled vertex of the planar gripper face.

[0026] Optionally, the gripping face is a first gripping face and wherein the frame carries a further array of suction cups that defines 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 configurations, 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 object’s position and orientation.

[0027] Optionally, the further array of suction cups is formed by 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 flat or thin objects. The narrow configuration allows for precise alignment and secure gripping along the container walls.

[0028] 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 first planar gripping face to an extended position in which the extendable suction cup extends beyond a planar outline of the 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, confined spaces where the primary gripping face cannot easily fit.

[0029] Optionally, the extension direction is generally parallel to a tapering direction of the acute angled vertex.

[0030] 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 container may for example be three-walled container, such as a roll-cage container, having three sides closed by a side wall and having one open side. The objects held by the container may hence be approached by the suction gripper from above through the open top as well as laterally from the open side.

[0031] Optionally, the system comprises a computer-vision device, configured for determining a spatial orientation of visible the objects in the pile of objects 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 gripped by the suction gripper.

[0032] Another aspect provides a method of gripping an object from a pile of objects held by a container using a suction gripper as described herein. The method comprises, using a computer-vision device, determine a spatial orientation of visible the objects in the pile of objects 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 gripped by the suction gripper.

[0033] Optionally, the method comprises selecting a suction zone of a plurality of independently controllable suction zones of the suction gripper, and positioning the suction gripper so as to bring the selected suction zone in gripping engagement with the grip face of the object.

[0034] It will be appreciated that any of the aspects, features and options described herein can be combined. It will particularly be appreciated that any of the aspects, features and options described in view of the suction gripper apply equally to the system and method, and vice versa.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings in which:

[0037] Figures 1 and 2 show an example of a suction gripper;

[0038] Figures 3A and 3B show a suction gripper mounted to a robotic arm;

[0039] Figure 4 shows a system, including a suction gripper and robotic arm;

[0040] Figures 5A-5D show examples of disorderly piled objects held by a roll-cage container;

[0041] Figures 6A and 6B show a suction gripper gripping a selected object from a disordered pile of objects;

[0042] Figures 7A-7D show another example of a gripper.

[0043] DETAILED DESCRIPTION Figure 1 shows an example of a suction gripper 100. The suction gripper 100 is configured for being mounted to a robotic arm 5 for gripping an object from a pile of objects held by a container 40.

[0044] The suction gripper 100 comprising a frame 10. The frame 10 carries an array of suction 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 of the bellows-type, including a flexible, accordion-like structure allowing for better adaptability to curved and irregular surfaces.

[0045] The array of suction cups 20 defines a planar gripping face 11 for being brought in engagement with the object. Here the planar gripping face 11 extends in the plane of the drawing. The array of suction cups 20 includes a staggered subarray of suction cups 21. The suction cups of the staggered subarray 21 are arranged in rows that are staggered with respect to each other. The suction cups of the staggered subarray 21 are arranged in a triangular pattern to form an acute angled vertex of the gripping face 11. The staggered subarray 21 in this example includes six suction cups, arranged in respective staggered rows of three, two and one suction cup.

[0046] The gripping face 11 formed by the array of suction cups 20 is in this example substantially quadrilateral-shaped. It has four straight edges and four vertices. The staggered subarray 21 forms an acute angled vertex of the 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 of symmetry.

[0047] The array of suction cups 20 also includes a non-staggered subarray of suction cups 22. The suction cups of the 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 of the non-staggered subarray 22 includes a four-by- four arrangement of suction cups, forming a square pattern of suction cups. Another part of the 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 of the square four-by-four pattern, effectively extending the bottom two rows by one suction cup.

[0048] The further acute angled vertex of the quadrilateral is formed by the non-staggered array. The obtuse angled vertex of the quadrilateral is formed at the transition between the non-staggered subarray 22 and the staggered subarray.

[0049] The frame 10 has in this example a plate-like body that extends in a plane parallel to the planar gripping face 11. The frame 10 has a quadrilateral-shaped outline in the plane parallel to the gripping face 11, particularly such that the planar outline of the frame 10, parallel to the planar gripping face 11, substantially resembles the shape of the gripping face 11 formed by the array of suction cups 20. Hence, the frame 10 conforms to the shape of the gripping face 11, to together define the quadrilateral shape.

[0050] Figure 2 shows the suction gripper 100 of figure 1 provided with an exemplary division into a plurality of independently controllable suction zones. In this example, the suction zones are non-overlapping. Each suction zone includes a two, three, or four suctions cups of the array in this example. It will be appreciated that figure 2 shows a particular example of a division into suction zones but that other divisions are also envisioned.

[0051] The staggered subarray 21 is subdivided into at least two independently controllable suction zones. One of the two suction zones is formed by a single row of suction cups that includes a suction cup positioned at the acute angled vertex and extends linearly along an outer edge of the staggered subarray 21. Another one of the two suction zones includes the remainder, here three, of the suction cups of the staggered subarray 21.

[0052] The non-staggered subarray 22 is in this example divided into five non-overlapping suction zones; four two-by-two suction zones and one two- by-one suction zone. This exemplary division of suction zones, in combination with the quadrilateral shape of the gripping face 11, provides great adaptability to different object shapes and sizes.

[0053] Figures 3A and 3B show two perspective views of the suction gripper 100 at an end of the robotic arm 5. The connection to the robotic arm 5 is omitted in figure 3B.

[0054] Figure 4 shows a system, comprising the suction gripper 100 of figures 1 and 2 mounted to a distal end of the 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 of the suction cups, e.g. one or more of the suction zones, appropriate for gripping an object held by 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 of the 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.

[0055] 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 of the container 40 faces the robotic arm 5. The open side 42 increases the accessibility to the objects of the pile by the suction gripper 100. The container 40 may alternatively have four closed sized and be only accessible through the open top 41.

[0056] 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 of the pile and distinguish different parcels from each other that have an exposed face. An orientation of an exposed face 2 of the particularly object 1 can be determined. Based on the determined orientation of the exposed face 2 in relation to the other objects and the container 40 wall, an orientation of the suction gripper 100 may be determined for approaching and engaging the object 1 with its gripping face 11. One or more suction zones may be selected for being activated vacuum gripping engagement with the object 1. In this example, the exposed face 2 of the object 1 is triangular shaped, substantially partially corresponding to the shape of the staggered subarray 21 of suction cups 21. Hence, here, the suction gripper 100 is positioned relative to the exposed object face such that the two suction zones of the staggered subarray 21 are activated and grip the object. None of the other suction zones are activated, to prevent additionally gripping any adjacent object.

[0057] Figures 7A-7D show examples of the suction gripper 100 of the 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 11. In these examples, the further array 30 includes a single row of suction cups. Figures 7A-7C show an example where the further array 30 is a single array of four suction cups that extends transverse to a pointing direction of the acute angled vertex. More particular, each of the suction cups of the further array 30 is selectively extendable. Figure 7 A shows each of the suction cups of the further array 30 being in a retracted state. Figure 7C shows each of the suction cups of the further array 30 being in an extended state. In the extended state, each of the suction cups of the further array 30 extends beyond the acute angled vertex. Figure 7B shows three suction cups of the further array 30 being in their retracted states, and one of the suction cups of the 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 of the container 40.

[0058] Figure 7D shows an example where the further array 30 is a single row of suction cups that extends along an edge of the quadrilateral shaped gripping face 11, here including six suction cups. In this example the suction cups are non-extendable, but they may alternatively be extendable.

[0059] Herein, the invention is described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein, without departing from the essence of the invention. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also envisaged.

[0060] However, other modifications, variations, and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative sense rather than in a restrictive sense.

[0061] 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 of other 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 of these measures cannot be used to an advantage.

Claims

Claims1. An end-of-arm suction gripper for gripping an object from a pile of objects held by a container, the suction gripper comprising a frame carrying an array of suction cups that defines a planar gripping face for being brought in engagement with the object, wherein 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, and wherein the staggered subarray forms an acute angled vertex of the gripping face.

2. The suction gripper according to claim 1, wherein the array of suction cups defines a substantially quadrilateral-shaped gripping face.

3. The suction gripper according to claim 1 or 2, wherein the array of suction cups forms an asymmetrically shaped gripping face.

4. The suction gripper according to any preceding claim, wherein the array of suction 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 of the gripping face.

5. The suction gripper according to any preceding claim, wherein the gripping face includes an obtuse angled vertex.

6. The suction gripper according to claim 5, wherein the obtuse angled vertex is formed at an interface between the staggered and the nonstaggered subarrays.

7. The suction gripper according to any preceding claim, wherein the frame is shaped such that a planar outhne of the frame, parallel to the planar gripping face, substantially resembles a shape of the gripping face formed by the array of suction cups.

8. The suction gripper according to claim 7, wherein the planar outline of the frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose an acute angled vertex.

9. The suction gripper according to claim 7 or 8, wherein the planar outline of the frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose an obtuse angled vertex.

10. The suction gripper according to any of claims 7-9, wherein the planar outline of the frame in a plane parallel to the planar gripping face includes at least two generally straight edges that enclose a straight angled vertex.

11. The suction gripper according to any of claims 7-10, wherein the planar outline of the frame in a plane parallel to the planar gripping face defines a quadrilateral, particular a convex quadrilateral.

12. The suction gripper according to any preceding claim, wherein the array of suction cups is divided into a plurality of independently controllable suction zones, each suction zone including a one or more suctions cups of the array.

13. The suction gripper according to claim 12, wherein the staggered subarray is subdivided into at least two independently controllable suction zones.

14. The suction gripper according to claim 13, wherein a suction zone of said at least two suction zones is formed by a single row of suction cups that includes a suction cup positioned at the acute angled vertex and extends linearly along an outer edge of the staggered subarray.

15. The suction gripper according to any of claims 12-14, wherein the plurality of independently controllable suction zones includes a suction zone having a non-staggered subarray of N by M suction cups arranged in a square or rectangular pattern, with N and M being non-zero integer numbers.

16. The suction gripper according to claim 15, the plurality of independently controllable suction zones includes four square or rectangular suction zones so arranged relative to each other to jointly form a nonstaggered square or rectangular pattern of 2N by 2M suction cups.

17. The suction gripper according to claim 16, wherein the nonstaggered square or rectangular pattern of 2N by 2M suction cups forms a right angled vertex of the planar gripper face.

18. The suction gripper according to any preceding claim, wherein the gripping face is a first gripping face and wherein the frame carries a further array of suction cups that defines a second planar gripping face that extends non-parallel, particularly transverse, to the first gripping face.

19. The suction gripper according to claim 18, wherein the further array of suction cups is formed by a single row of suction cups that extends parallel to the first planar gripper face.

20. The suction gripper according to claim 19, wherein the single row of suction cups extends along an edge of the first gripper face.

21. The suction gripper according to any of claims 18-20, wherein 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 first planar gripping face to an extended position in which the extendable suction cup extends beyond a planar outline of the first planar gripping face.

22. The suction gripper according to claim to claim 21, wherein the extension direction is generally parallel to a tapering direction of the acute angled vertex.

23. A system comprising: 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 according to any preceding claim for gripping an object from the pile of objects.

24. A method of gripping an object from a pile of objects held by a container using a suction gripper according to any of claims 1-22, comprising, using a computer-vision device, determine a spatial orientation of visible the objects in the pile of objects 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 gripped by the suction gripper.

25. The method according to claim 24, comprising selecting a suction zone of a plurahty of independently controllable suction zones of the suction gripper, and positioning the suction gripper so as to bring the selected suction zone in gripping engagement with the grip face of the object.

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