An internally expandable multi-convex pneumatic soft gripper

Abstract

An embodiment of the present application discloses an internally expandable multi-convex pneumatic soft gripper, comprising: a two-dimensional follow-up chain and a soft structure composed of a rigid-flexible coupling structure; the two ends of the two-dimensional follow-up chain are buckled through a closed fastener to form an encircling structure; the soft structure includes a restraint layer and an expansion layer wrapped outside the two-dimensional follow-up chain; the expansion layer is located inside the encircling structure, and the expansion layer is fixedly connected to the periphery of the restraint layer to form a closed inner cavity; a plurality of non-stretchable rings are arranged at intervals on the soft structure, so that a plurality of convex hulls are formed after the expansion layer is ventilated. The invention has the advantages of simple structure, strong shape adaptability and strong grasping reliability, and can be applied to fields such as industrial robot operation and bionic robot attachment.

Description

Technical Field

[0001] This application relates to the technical field of soft robots, and particularly to an internally expandable multi-lobe pneumatic soft gripper. Background Art

[0002] In fields such as industry, agriculture and forestry, and service industries, robots are often required to perform reliable clamping or operation tasks. The objects of these tasks have diverse shapes. For example, tasks such as sorting of fragile materials, fruit and vegetable picking, grasping of daily necessities, and human-computer interaction require robots to have strong shape adaptability and reliability.

[0003] In recent years, many detailed studies have been carried out in the field of end effectors at home and abroad, such as excellent end effectors like human hand imitation systems, suction cup array systems, and hook and thorn gripper systems. These robotic systems have rigid structures and can adsorb or operate on some specified objects. However, robots often need to interact with humans, living organisms, or fragile objects during operation. Rigid end effectors often have limitations when facing these application objects. Therefore, by leveraging the intersection of multiple disciplines such as robotics and materials science, soft end effectors constructed using flexible materials and intelligent materials have emerged, providing broader ideas for the design of robot ends. However, the existing soft end effectors currently have complex structures and poor shape adaptability, and cannot reliably complete the clamping work. Therefore, the present invention proposes an internally expandable multi-lobe pneumatic soft gripper. Summary of the Invention

[0004] The embodiments of this application provide an internally expandable multi-lobe pneumatic soft gripper, which has the advantages of simple structure, strong shape adaptability, and strong gripping reliability.

[0005] In view of this, this application provides an internally expandable multi-lobe pneumatic soft gripper, including: a two-dimensional follow-up chain and a soft structure composed of a rigid-flexible coupling structure;

[0006] Both ends of the two-dimensional follow-up chain are buckled through a closing fastener to form an encircling structure;

[0007] The soft structure includes a restraint layer and an expansion layer wrapped outside the two-dimensional follow-up chain;

[0008] The expansion layer is located inside the encircling structure, and the expansion layer is fixedly connected to the periphery of the restraint layer to form a closed inner cavity;

[0009] A plurality of non-stretchable rings are arranged at intervals on the soft structure, so that a plurality of lobes are formed after the expansion layer is ventilated.

[0010] Optionally, the two-dimensional follow-up chain includes multiple rigid rib plates;

[0011] The rigid rib plates are all connected by foldable flexible joints.

[0012] Optionally, rib plate holes are provided on the rigid rib plates.

[0013] Optionally, the number of the rib plate holes is multiple.

[0014] Optionally, the shape of the rib plate holes is circular.

[0015] Optionally, a base for connecting with other robot bodies is arranged in the middle of the two-dimensional follow-up chain.

[0016] Optionally, an air inlet device is connected to the expansion layer.

[0017] Optionally, the two-dimensional follow-up chain is integrally formed by 3D printing with PLA material.

[0018] Optionally, the closing fastener is a dovetail groove structure fastener.

[0019] Optionally, the material of the soft structure is soft silicone.

[0020] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages: including a two-dimensional follow-up chain and a soft structure composed of a rigid-flexible coupling structure, the two ends of the two-dimensional follow-up chain are buckled through a closing fastener to form an encircling structure, the soft structure includes a limiting layer and an expansion layer wrapped outside the two-dimensional follow-up chain, the expansion layer is located inside the encircling structure, and the expansion layer is fixedly connected to the periphery of the limiting layer to form a closed inner cavity; a plurality of non-stretchable rings are arranged at intervals on the soft structure, so that a plurality of convex bumps are formed after the expansion layer is ventilated. On the basis of realizing clamping by adopting a rigid-flexible coupling structure, this clamping device realizes clamping of different objects by making a plurality of inner convex bumps bulge on the expansion layer after ventilation. Its structure is simple, and it can be applied to industrial robots or bionic robots, and is installed at their ends to realize operation or attachment. At the same time, the two-dimensional follow-up chain composed of a rigid-flexible coupling structure retains the degrees of freedom in the plane and limits the degrees of freedom outside the plane, thereby ensuring the feasibility of operating and supporting the robot. And by using the expansion layer to expand inward to squeeze the clamped object, the object can be adapted and reliably clamped. Among them, the multi-convex bump structure has a higher degree of fit to the object, enhancing the adaptability of the clamping device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the inner-expansion multi-convex bump pneumatic soft body clamping device in the normal working state in the embodiment of the present application;

[0022] Figure 2 is a schematic structural diagram of the two-dimensional follow-up chain in the embodiment of the present application;

[0023] Figure 3Schematic diagram of the software structure in the embodiments of the present application;

[0024] Figure 4 Schematic diagram of the structure of the inner-expanding multi-convex-hull pneumatic soft gripper in the non-operating state in the embodiments of the present application;

[0025] Figure 5 Schematic diagram of the envelope of the inner convex hull when the inner-expanding multi-convex-hull pneumatic soft gripper grips a square rod in the embodiments of the present application;

[0026] Figure 6 Schematic diagram of the envelope of the inner convex hull when the inner-expanding multi-convex-hull pneumatic soft gripper grips an elliptical rod in the embodiments of the present application;

[0027] Among them, the reference numerals are:

[0028] 1 - two-dimensional follower chain, 2 - closing fastener, 3 - base, 4 - expansion layer, 5 - convex hull, 6 - rigid rib plate, 7 - flexible joint, 8 - rib plate hole, 9 - restraint layer, 10 - collar. Detailed implementation manners

[0029] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0030] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0031] Unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0032] An embodiment of an internally expanding multi-convex pneumatic soft gripper is provided in this application. For details, please refer to Figure 1 .

[0033] The internally expanding multi-convex pneumatic soft gripper in this embodiment includes: a two-dimensional follow-up chain 1 and a soft structure composed of a rigid-flexible coupling structure. The two-dimensional follow-up chain 1 provides out-of-plane support for the soft structure while maintaining in-plane degrees of freedom to ensure the effectiveness and dexterity of gripping. The two ends of the two-dimensional follow-up chain 1 are buckled through a closing fastener 2 to form a surrounding structure. The closing fastener 2 is fixedly connected to the two-dimensional follow-up chain 1 to achieve pre-gripping of an object. The soft structure includes a restraint layer 9 and an expansion layer 4 wrapped outside the two-dimensional follow-up chain 1. The expansion layer 4 is located inside the surrounding structure, and the expansion layer 4 is fixedly connected to the periphery of the restraint layer 9 to form a closed inner cavity. A plurality of non-stretchable rings 10 are arranged at intervals on the soft structure, so that when the expansion layer 4 is inflated, a plurality of convex hulls 5 are formed. Specifically, the expansion layer 4 is welded to the periphery of the restraint layer 9 to form a closed inner cavity. When gas is introduced, it can expand. The plurality of rings 10 distributed at intervals along the length direction prevent the expansion layer 4 at the rings 10 from expanding, while other areas bulge and expand, thereby forming a plurality of convex hulls 5.

[0034] It should be noted that: on the basis of realizing gripping by adopting a rigid-flexible coupling structure, this gripper further realizes gripping of different objects by making a plurality of inner convex hulls 5 bulge on the expansion layer 4 after ventilation. Its structure is simple and can be applied to industrial robots or bionic robots. It is installed at their ends to realize operation or attachment. At the same time, for most operation tasks or applications such as environmental attachment, a completely soft mechanism is prone to unexpected passive deformation and should be restricted. This gripper adopts a two-dimensional follow-up chain 1 composed of a rigid-flexible coupling structure to maintain in-plane degrees of freedom and restrict out-of-plane degrees of freedom, thereby ensuring the feasibility of operating and supporting the robot. And by using the expansion layer 4 to expand inward and squeeze the object to be gripped, it can adapt to and reliably grip the object. Among them, the multi-convex hull 5 structure has a higher degree of fit to the object, enhancing the adaptability of the gripper.

[0035] The above is Embodiment 1 of an internally expanding multi-convex pneumatic soft gripper provided by this application. The following is Embodiment 2 of an internally expanding multi-convex pneumatic soft gripper provided by this application. For details, please refer to Figures 1 to 6 .

[0036] The internal expansion multi-convex pneumatic soft gripper in this embodiment includes: a two-dimensional follow-up chain 1 composed of a rigid-flexible coupling structure and a soft structure. The two ends of the two-dimensional follow-up chain 1 are buckled through a closing fastener 2 to form an encircling structure. The soft structure includes a restraining layer 9 and an expansion layer 4 wrapped outside the two-dimensional follow-up chain 1. The expansion layer 4 is located inside the encircling structure, and the expansion layer 4 is fixedly connected to the periphery of the restraining layer 9 to form a closed inner cavity. A plurality of non-stretchable rings 10 are arranged at intervals on the soft structure, so that a plurality of convex hulls 5 are formed after the expansion layer 4 is ventilated.

[0037] It should be noted that: The two-dimensional follow-up chain 1 retains all degrees of freedom in the plane, that is, a total of three degrees of freedom including translation in two directions in the plane and rotation around the plane normal, while restricting all degrees of freedom outside the plane to ensure that no unexpected deformation occurs, thereby ensuring the basic form of planar bending clamping.

[0038] As Figure 2 shown, the two-dimensional follow-up chain 1 includes multiple rigid rib plates 6, and the multiple rigid rib plates 6 are connected by foldable flexible joints 7.

[0039] The two-dimensional follow-up chain 1 can be integrally formed by 3D printing with PLA material. Specifically, the two-dimensional follow-up chain 1 is integrally formed by 3D printing with PLA materials distributed at intervals of thick and thin, and then folded along the width direction at each thin concave part to make it plastically deformed without tearing, thereby forming the flexible joint 7, and thus forming the two-dimensional follow-up chain 1.

[0040] The material of the soft structure can be soft silicone. Rib plate holes 8 are opened on the rigid rib plates 6 and can be embedded in the silicone to form the restraining layer 9, where the number of rib plate holes 8 can be multiple, and the shape of the rib plate holes 8 can be circular.

[0041] Specifically, the two-dimensional follow-up chain 1 and the expansion layer 4 core are suspended and placed flat in the mold, and then liquid silicone is poured into the mold. After solidification, the integrally formed restraining layer 9 and expansion layer 4 can be obtained. Among them, due to the rib plate holes 8 designed on the rigid rib plates 6 of the two-dimensional follow-up chain 1, the liquid silicone can penetrate into the rib plate holes 8 and form an inextensible restraining layer 9 after solidification. Then the core is taken out, the opening is sealed, and the closing fastener 2 is installed to obtain the main part of this gripper. Finally, non-stretchable rings 10 are sleeved at intervals along the length direction, so that the expansion layer 4 has expandable and non-expandable areas, and the convex hulls 5 are formed after the expandable area is ventilated.

[0042] A base 3 for connecting with other robot bodies is arranged in the middle of the two-dimensional follow-up chain 1. Specifically, this gripper can be installed at the end of an industrial robot or a bionic robot through the base 3, the closing fastener 2 is buckled, the object is pre-clamped, and then the object is clamped stably by ventilation. Thus, both adaptable and reliable clamping can be achieved.

[0043] The expansion layer 4 is connected to an air intake device.

[0044] The closing fastener 2 is a dovetail groove structure fastener. Specifically, a male and a female dovetail groove structure are respectively provided at both ends of the two-dimensional follow-up chain 1. After being buckled, the gripper can realize pre-gripping around the object to be gripped. When the ventilation expansion layer 4 bulges multiple convex bumps 5, it can expand and press the envelope of the object to be gripped. In this way, it can not only adapt to the shape and size of the object, but also grip the object firmly.

[0045] This gripper is straight and extended in the non-working state (as Figure 4 shown). In specific implementation, first, the gripper is surrounded around the object to be gripped and fastened with the closing fastener 2 to realize pre-gripping. At this time, the gripper is in a closed surrounding state. Then, gas is introduced into the expansion layer 4 of the gripper, and multiple convex bumps 5 will bulge in the expandable area outside the collar 10. The convex bumps 5 expand inward, press the object to be gripped, and adaptively fit on the surface of the object to form a contact envelope (as Figure 5 and Figure 6 shown). In addition, the pressing force presses tightly on the surface of the object, so that a large frictional force can be generated between the expansion layer 4 and the object, thereby gripping the object reliably. Thus, the adaptive and reliable gripping of the object by the gripper is realized. Installing this gripper at the end of an industrial robot can perform operation tasks; installing this gripper on a bionic climbing robot, etc., can complete the attachment during the climbing process of the robot and realize climbing.

[0046] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. An internally expandable multi-convex pneumatic soft gripper, characterized in that, Including: A two-dimensional follow-up chain and a soft structure composed of a rigid-flexible coupling structure; Both ends of the two-dimensional follow-up chain are buckled through a closed fastener to form an encircling structure; The soft structure includes a limiting layer and an expansion layer wrapped outside the two-dimensional follow-up chain; The expansion layer is located inside the encircling structure, and the expansion layer is fixedly connected to the periphery of the limiting layer to form a closed inner cavity; A plurality of non-stretchable collars are arranged at intervals on the soft structure, so that a plurality of convex bumps are formed after the expansion layer is ventilated; A base for connecting with other robot bodies is arranged in the middle of the two-dimensional follow-up chain; The expansion layer is connected with an air inlet device.

2. The internal expansion multi-convex pneumatic soft gripper according to claim 1, wherein, The two-dimensional follow-up chain includes multiple rigid rib plates; Multiple rigid rib plates are connected through foldable flexible joints; 3. The inner-expansion multi-convex pneumatic soft gripper according to claim 2, characterized in that, Rib plate holes are formed in the rigid rib plates; 4. The inner-expansion multi-convex-hull pneumatic soft gripper according to claim 3, characterized in that, The number of the rib plate holes is multiple; 5. The internal expansion multi-convex pneumatic soft gripper according to claim 3, characterized in that, The shape of the rib plate holes is circular; 6. The inner-expanding multi-convex-hull pneumatic soft gripper according to claim 1, characterized in that, The two-dimensional follow-up chain is integrally formed by 3D printing with PLA material; 7. The internal expansion multi-convex pneumatic soft gripper according to claim 1, characterized in that The closed fastener is a dovetail groove structure fastener; 8. The internal expansion multi-convex pneumatic soft gripper according to claim 1, wherein, The material of the soft structure is soft silicone.

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