Robotic pneumatic gripper, gripping process and pneumatic circuit

Abstract

A robotic pneumatic gripper (10) comprising: a robotic arm (11); an effector (12) comprising at least one gripping element (14) such as a suction cup or foam; and a pneumatic circuit for controlled vacuuming of at least one gripping element (14), the pneumatic circuit comprising: a vacuum source (15); a main line (16) connecting the vacuum source (15) to the gripping element (14); and an auxiliary line (18) connected to the main line at one or more nodes (17), the auxiliary line (18) being equipped with a valve (19) configured to switch between a closed position (F) in which the auxiliary line (18) is sealed, and an open position (O) in which the node (17) is fluidly connected to the atmosphere (A). Abstract figure: Figure 3

Description

Title of the invention: Robotic pneumatic gripper, gripping method and pneumatic circuit Technical field

[0001] The present disclosure relates to the field of logistics, particularly in automated warehouses, and more particularly to “picking” operations, an Anglo-Saxon term which designates the action of grasping an article to extract it from a group of articles present in a container, and of placing it in another specific container, for example for the preparation of commercial orders. Prior art

[0002] It is known to carry out such gripping operations by robotic devices, in particular by programmable arms, generally mobile along 5 or 6 axes, and equipped at their mobile end with an effector provided with a gripping member, comprising for example a suction cup and / or foam, making it possible to ensure the operation of gripping the objects.

[0003] Objects can be of different sizes, shapes and weights, or even different surface textures.

[0004] In order for the gripping member to be able to grasp the object, a pneumatic circuit is generally provided which may comprise a vacuum source, such as a pump, configured to create, at the gripping member, a depression necessary for grasping the object.

[0005] In such a system, it is necessary to deactivate the pump to cancel the suction effect for each object depositing operation. Such a method is not desirable because restarting the vacuum source successively can degrade it prematurely. It is generally recommended not to exceed ten start-ups per hour. However, the rates that must be maintained, for an industrial “picking” application, are more in the order of 600 gripping operations (gripping and depositing cycle) per hour. A simple suction system is therefore not suitable for gripping applications in an automated warehouse.

[0006] It was therefore necessary to develop a means of gripping and releasing an object while keeping the vacuum source in constant working order.

[0007] A means such as a valve makes it possible to open the pneumatic circuit between the vacuum source and the gripping member, and thus punctually connect the gripping member to the atmosphere to release the gripped objects.

[0008] Patent document WO 2019 / 094382-Al discloses in particular the use of a 3-way, 2-position valve to allow alternate gripping and removal of objects with rates adapted to industrial use, while keeping the vacuum source in constant working order.

[0009] However, the integration of such a valve into the circuit remains complex and its use can induce pressure losses which degrade the performance of the device. Summary

[0010] The present disclosure improves the situation by proposing a system of simple design, which guarantees a long service life of the vacuum source and which reduces pressure losses in comparison with the design described above.

[0011] A robotic pneumatic gripper is proposed comprising: - a robotic arm; - an effector disposed at a movable end of the robotic arm, the effector comprising at least one gripping member such as a suction cup or foam; and - a pneumatic circuit for controlled vacuuming of the at least one gripping member, the pneumatic circuit comprising: • a vacuum source; • a main pipe connecting the vacuum source to the gripping member; and • an auxiliary pipe connected to the main pipe at one or more nodes, the auxiliary line being provided with a valve configured to switch between a closed position in which the auxiliary line is sealed, and an open position in which the node is fluidically connected to the atmosphere.

[0012] The features set out in the following paragraphs may, optionally, be implemented, independently of one another or in combination with one another:

[0013] According to an improvement, the valve is a 2-way, 2-position valve.

[0014] According to an improvement, the node is unique.

[0015] According to an improvement, all or part of the pneumatic circuit is integrated into the robotic arm, and therefore mobile with it.

[0016] According to an improvement, the vacuum source is a Venturi effect.

[0017] According to an improvement, the vacuum source is a vane vacuum pump.

[0018] According to an improvement, the vacuum source is a turbine pump.

[0019] According to an improvement, the valve has a mouth open towards the atmosphere and a filtration device at the level of said mouth.

[0020] The present disclosure further relates to a method comprising the following steps: - Activation of the vacuum source;

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[0028] - Approach of at least one gripping organ of an object to be handled; - Gripping the object by establishing a vacuum in the gripping member, obtained either by activating the vacuum source if the valve is normally closed, or by switching the valve to the closed position; - Moving the object by the motorized arm to a desired location, - Removal of the object by releasing the gripping member into the atmosphere, obtained by switching the valve to the open position. The present disclosure also relates to a pneumatic circuit for controlled vacuuming of a gripping member, the circuit comprising: - a vacuum source; - a main pipe intended to connect the vacuum source to the gripping member; and - an auxiliary pipe connected to the main pipe at one or more nodes, the auxiliary pipe being provided with a valve configured to switch between a closed position in which the auxiliary pipe is closed, and an open position in which the node is fluidically connected to the atmosphere. Brief description of the drawings Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: Fig.l [Fig.l] shows a robotic pneumatic gripper according to one embodiment. Fig. 2 [Fig.2] shows a diagram of a state-of-the-art pneumatic circuit. Fig. 3 [Fig.3] shows a diagram of the pneumatic circuit according to one embodiment of the present disclosure. Description of the embodiments [Fig.l] shows a robotic pneumatic gripper 10 according to the present disclosure. The gripper 10 is shown during an operation of gripping an object 1. The gripper 10 may comprise a robotic arm 11, for example a programmable robotic arm movable 360 ​​degrees along several axes, in particular along 5 or 6 axes. Other robotic structures are also conceivable, such as for example a gantry structure. The gripper 10 may include a processor (not shown) capable of executing a program that contains instructions for controlling the gripper. It may also include a human-machine interface to control it manually.

[0029] The gripper may in particular be equipped with an optical sensor (not shown), for example a camera, to collect information on the object to be grasped, in particular its position, its shape, its size, etc.

[0030] The robotic arm 11 may comprise a free end 13, opposite an end fixed to the ground or to any structure. At this free end 13 is arranged an effector 12, which is provided with at least one gripping member 4, 14. It may be advantageous to provide the effector 12 with several gripping members, in particular for gripping objects of a more complex shape, larger or heavier.

[0031] The gripper 10 may comprise a pneumatic circuit, configured to circulate a gaseous fluid, for example air, and to allow the creation of a suction force at the gripping member 4, 14.

[0032] A state-of-the-art pneumatic circuit will now be described with reference to [Fig.2].

[0033] Such a known circuit comprises a first pipe 6, which makes it possible to fluidly connect a vacuum source 5 to the gripping member 4 via a valve 9. The valve is generally of the “3 / 2” type, that is to say that it distributes the fluid between three channels, typically an inlet, an outlet and an exhaust, and can switch between two positions: a closed position F and an open position O (shown in [Fig.2]).

[0034] The circuit further comprises a second pipe 7 which fluidly connects the outlet of the valve 9 to the gripping member 4, and comprises a third pipe 8 which fluidly connects the valve 9 to atmospheric pressure. Generally, it may be a pipe open to the atmosphere A.

[0035] Thus, the closed position F of the valve 9 makes it possible to connect the first pipe 6 to the second pipe 7, and thus to fluidically connect the vacuum source 5 to the gripping member 4 to create a depression in the gripping member and thus create the suction force necessary for gripping an object.

[0036] Conversely, the open position O makes it possible to block the first pipe 6, and makes it possible to connect the second pipe 7 to the third pipe 8, and thus to connect the gripping member 4 to the atmosphere A. This has the consequence of returning the gripping member 4 to atmospheric pressure and stopping the suction force to release the object.

[0037] This known pneumatic circuit embodiment makes it possible to avoid frequent restarts of the vacuum source, which can thus always remain active. However, the “3 / 2” valve and the three separate pipes remain complex to integrate into the gripper system.

[0038] Furthermore, this type of circuit can induce a large number of restrictions, due in particular to the internal geometric complexity of the valve “3 / / 2”, which involve a loss of vacuum which can reach 20%, at the level of the gripping member, compared to the vacuum level at the outlet of the vacuum source 5. This degrades the performance of the system, in particular in operations for gripping objects with a porous surface or having a high mass.

[0039] Furthermore, in such a known circuit, when the valve is in the closed position F, the vacuum source continues to “suck” against the inlet of the valve which is blocked. This is not desirable for optimizing the service lives of the vacuum source 5 and the valve 9, which may see their internal components deteriorate prematurely. This may also have the effect of unnecessarily increasing the energy consumption of the vacuum source.

[0040] An embodiment of the present disclosure will now be described with reference to [Fig.3].

[0041] The pneumatic circuit of the pneumatic gripper 10, according to an embodiment of the present disclosure, may comprise a main pipe 16 connecting the vacuum source 15 to the gripping member 14, and an auxiliary pipe 18 connected to the main pipe at at least one node 17.

[0042] The vacuum source 15 may be of the Venturi effect type or may consist of a vane vacuum pump or a turbine vacuum pump. Alternatively, several vacuum sources of the same type or different types may be combined.

[0043] The at least one node 17 makes it possible to fluidically connect the auxiliary pipe to the main pipe at an intermediate point between the vacuum source 15 and the gripping member 14. A node within the meaning of the present disclosure is therefore a junction with at least three orifices making it possible to connect at least two pipes.

[0044] The auxiliary pipe 18 may be provided with a valve 19 which may be configured to alternately close and open the circuit to the atmosphere. When this valve 19 is closed, the depression created by the vacuum source reaches the gripping member 14: it is thus possible to grasp an object. When the valve 19 is open, the node 17 is vented to the atmosphere and the vacuum source 15, still in operation, no longer creates a depression in the main pipe 16: the grasped object is released.

[0045] In a preferred embodiment, the circuit comprises a single node. The fluid can then circulate freely in three branches, composed of the two main and auxiliary pipes, which join at node 17, as shown in [Fig.3].

[0046] In a preferred embodiment, the valve is of the “2 / 2” type, and allows two ways to be connected, an inlet way and an outlet way, and can switch between two positions: a closed position F and an open position O. Thus, the circuit greatly gains in simplicity of implementation which provides both a gain economical, but also a beneficial effect of limiting pressure losses in the valve, the latter being less complex and presenting fewer restrictions than the state-of-the-art “3 / 2” valves.

[0047] With this configuration, the closed position F of the valve 19 makes it possible to close the connection of the auxiliary pipe with the atmosphere A, and thus to fluidically connect the vacuum source 15 to the gripping member 14 to create a depression in the gripping member and thus create the suction force necessary for gripping an object.

[0048] Conversely, the open position O makes it possible to connect the main pipe 16 to the auxiliary pipe 18, and thus to connect the gripping member 14, and the vacuum source 15, to the atmosphere A. This has the consequence of returning the gripping member 14 to atmospheric pressure and stopping the suction force to release the object.

[0049] When the valve 19 is in the open position O, the vacuum source 15 is therefore also connected to the atmosphere A by a mouth 20 of the valve, or of the auxiliary pipe. The system being configured so that the vacuum source 15 remains in working order, this results in uninterrupted suction at the mouth by the vacuum source 15. The pneumatic gripper 10 can therefore comprise, at the mouth 20 of the valve 19, a filtration device 21, such as for example a grid, to prevent the suction of material which could damage the internal components of the circuit, in particular of the valve 19 and / or of the vacuum source 15.

[0050] All or part of the pneumatic circuit can be integrated into the robotic arm, and therefore move with it.

[0051] The present disclosure also relates to a method for gripping objects implemented by a pneumatic gripper 10 as previously described, the method comprising the following steps: - Activation of vacuum source 15; - Approach of at least one gripping organ of an object 1 to be handled; - Seizure of object 1 by establishing a depression in the organ of grip 14, obtained either by activating the vacuum source if the valve is normally closed, or by switching the valve 19 to the closed position if it is normally open; - Moving the object 1 by the motorized arm 11 to a desired location; and - Removal of the object 1 by releasing the gripping member 14 into the atmosphere, obtained by switching the valve 19 to the open position O.

[0052] The first activation step is only necessary if the vacuum source has been deactivated for some reason, for example at the end of the previous gripping cycle, or for example during an emergency stop, or if it is the first gripping cycle. Generally, the vacuum source 15 is activated constantly.

[0053] The valve 19 can be normally open or normally closed. In a preferred embodiment, it is normally closed, which implies that the valve 19 is only controlled for switching to the open position and depositing the object 1. But it is also possible to provide that the valve is normally open, thus the valve will be controlled for gripping the object. The valve can alternatively be double-acting and therefore without a default preferred position. Industrial application

[0054] The present technical solutions can be applied in particular in the field of automated warehouse logistics, and more particularly during “picking” operations, for example for the preparation of commercial orders. List of reference signs

[0055] - 1: object - 4, 14: gripping organ - 5, 15: vacuum source - 6: first conduct - 7: second line - 8: third line - 9.19: valve - 10: robotic pneumatic gripper - 11: robotic arm - 12: effector - 13: free end - 14: gripping organ - 15: vacuum source - 16: main line - 17: node - 18: auxiliary line - 19: valve - 20: mouthpiece - 21: filtration device - A: atmosphere - F: closed position - O: open position

Claims

Claims

1. Robotic pneumatic gripper (10) comprising: - a robotic arm (11); - an effector (12) arranged at a movable end of the robotic arm (11), the effector (12) comprising at least one gripping member (14) such as a suction cup or a foam; and - a pneumatic circuit for controlled vacuuming of the at least one gripping member (14), the pneumatic circuit comprising: • a vacuum source (15); • a main pipe (16) connecting the vacuum source (15) to the gripping member (14); and • an auxiliary pipe (18) connected to the main pipe at one or more nodes (17), the auxiliary pipe (18) being provided with a valve (19) configured to switch between a closed position (F) in which the auxiliary pipe (18) is closed, and an open position (0) in which the node (17) is fluidically connected to the atmosphere (A).

2. A gripper (10) according to claim 1, wherein the valve (19) is a 2-way, 2-position valve.

3. A gripper (10) according to claim 1 or 2, wherein the node (17) is single.

4. Gripper (10) according to one of the preceding claims, in which all or part of the pneumatic circuit is integrated into the robotic arm, and therefore movable with it.

5. Gripper (10) according to any one of claims 1 to 4 in which the vacuum source (15) is a Venturi effect.

6. A gripper (10) according to any one of claims 1 to 4 wherein the vacuum source (15) is a vane vacuum pump.

7. A gripper (10) according to any one of claims 1 to 4 wherein the vacuum source (15) is a turbine pump.

8. Gripper (10) according to any one of the preceding claims, in which the valve comprises a mouth (20) open towards the atmosphere (A) and a filtration device (21) at the level of said mouthpiece (20).

9. A method of gripping objects implemented by a gripper (10) according to any one of the preceding claims, the method comprising the following steps: - Activation of the vacuum source (15); - Approach of at least one gripping organ of an object (1) to be handled; - Gripping the object (1) by establishing a vacuum in the gripping member (14), obtained either by activating the vacuum source if the valve is normally closed, or by switching the valve (19) to the closed position (F); - Moving the object (1) by the motorized arm (11) to a desired location, - Removal of the object (1) by releasing the gripping member (14) into the atmosphere, obtained by switching the valve (19) to the open position (O).

10. Pneumatic circuit for controlled vacuuming of a gripping member, the circuit comprising: - a vacuum source (15); - a main pipe (16) intended to connect the vacuum source (15) to the gripping member (14); and - an auxiliary pipe (18) connected to the main pipe at one or more nodes (17), the auxiliary line (18) being provided with a valve (19) configured to switch between a closed position (F) in which the auxiliary line is closed, and an open position (O) in which the node (17) is fluidically connected to the atmosphere (A).

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