Multi-cavity soft finger, manipulator and method

Abstract

The invention discloses a multi-cavity soft finger, a manipulator and a method, and relates to the technical field of soft manipulators, the soft finger comprises at least two strain layers, a limiting layer and a wrapping layer, the strain layers are arranged side by side, the cross sections of the strain layers are trapezoidal, and the interiors of the strain layers are cavities; one end of the strain layer is closed, and the other end is used for inputting air pressure; the limiting layer is fixed on the narrow end surface of the strain layer; and the wrapping layer wraps the outer sides of all the strain layers and the limiting layers, so that the strain layers form a multi-cavity structure. The multiple independent cavities are spliced into a whole, the soft manipulator can be better attached to an object by adjusting the input air pressure of each cavity, the contact area between the soft manipulator and the object is increased, and the grabbing load capacity and stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soft manipulators, and in particular to a multi-cavity soft finger, a manipulator and a method. Background Art

[0002] As the end effector of traditional industrial robots, manipulators can assist industrial robots in completing operations such as grasping, moving and assembling target objects. However, traditional manipulators are usually made of rigid materials and have the advantages of high motion accuracy, high rigidity and strong grasping force. However, due to their poor flexibility and limited degrees of freedom, they lack adaptability and flexibility in motion and are difficult to apply to complex working environments and narrow working spaces. They are also unable to complete the grasping tasks of certain specific objects, such as fragile objects and electronic products. Soft robots made of flexible materials can achieve deformation motion according to their material properties and structural morphology, and have stronger adaptability than rigid robots. They can adaptively change their own shape according to the working environment and the shape and size of the target object. Therefore, they have become one of the most popular research fields in recent years and have broad application prospects in rescue detection, medical equipment, service robots and intelligent manufacturing.

[0003] However, existing soft manipulators still have the following key problems: the contact area between the soft manipulator and the grasped object is small, the stress is relatively concentrated, and when grasping smooth objects or irregular objects, the contact area is increased only by deforming the soft material, resulting in poor stability; common soft pneumatic manipulators have a single cavity structure with poor load capacity, and increasing the input air pressure to increase the load capacity will cause the soft manipulator to expand radially severely or even rupture. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a multi-cavity soft finger, manipulator and method, which splice multiple independent cavities into a whole, and enable the soft manipulator to better fit the object by adjusting the input air pressure of each cavity, thereby increasing the contact area with the object and improving the load capacity and stability of the grasping.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a multi-cavity soft finger, comprising:

[0007] At least two strain layers are arranged side by side, the cross section of each strain layer is trapezoidal and the interior is a cavity; one end of each strain layer is closed and the other end is used to input air pressure;

[0008] a confinement layer, fixed to the narrow end surface of the strain layer;

[0009] The wrapping layer is wrapped around the outside of all the strain layers and the restriction layers, so that the strain layers form a multi-chamber structure.

[0010] As a further implementation, the strain layers are provided with three, the cross sections of the strain layers on both sides are oriented in the same direction, and the cross sections of the middle strain layer are oriented in the opposite direction to the cross sections of the strain layers on both sides;

[0011] The middle strain layer and the strain layers on both sides are input with opposite air pressures.

[0012] As a further implementation, the restriction layer is a flat plate structure, which is bonded to the strain layer by an adhesive.

[0013] As a further implementation, the material hardness of the restriction layer is higher than the material hardness of the strain layer, so that the soft finger bends toward the restriction layer side under the action of air pressure.

[0014] As a further implementation, the wrapping layer is provided with a plurality of hollow areas.

[0015] As a further implementation, a protrusion is provided at one end of the wrapping layer, and the protrusion is used to cooperate with the gripper base.

[0016] In a second aspect, an embodiment of the present invention further provides a multi-cavity soft manipulator comprising at least two of the above-mentioned soft fingers.

[0017] As a further implementation, the soft finger is installed on a gripper base, and a socket component is installed at the mating end of the soft finger and the gripper base, and the socket component is used to connect the pneumatic device.

[0018] As a further implementation, the gripper base includes a connecting bracket, the connecting bracket is connected to a plurality of fixed brackets, and the soft fingers are plugged into the fixed brackets.

[0019] In a third aspect, an embodiment of the present invention further provides a working method of a multi-cavity soft manipulator, wherein the soft fingers are inflated by a pneumatic device, wherein when positive pressure is input into the internal cavities of the strain layers on both sides and negative pressure is input into the internal cavity of the middle strain layer at the same time, the wrapping layer is driven to bend inwardly to achieve inward grasping;

[0020] When negative pressure is input into the internal cavities of the strain layers on both sides and positive pressure is input into the internal cavity of the middle strain layer at the same time, the wrapping layer is driven to bend laterally outwards and open outwards.

[0021] The beneficial effects of the present invention are as follows:

[0022] The soft fingers of the present invention are provided with multiple cavities, which increase the width of the manipulator and improve the load capacity of the manipulator; positive pressure or negative pressure is input into the cavity according to the grasping requirements, and the fingers can be controlled to grasp inward or bend outward; according to the shape of the grasped object, the size of the air pressure input into each cavity can be adjusted so that the surface of the soft fingers in contact with the object can better fit the object, thereby increasing the contact area with the object and improving the grasping stability, and is suitable for grasping objects with complex shapes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 is a schematic diagram of a soft finger structure according to one or more embodiments of the present invention;

[0025] Figure 2 is an axonometric diagram of a strain layer according to one or more embodiments of the present invention;

[0026] FIG3( a ) is a front view of a strain layer according to one or more embodiments of the present invention;

[0027] FIG3( b ) is a cross-sectional view taken along line AA of FIG3( a );

[0028] Figure 4 is a schematic diagram of the structure of a soft manipulator according to one or more embodiments of the present invention;

[0029] Figure 5 is a schematic diagram of the gripper base structure according to one or more embodiments of the present invention;

[0030] FIG6( a) is a side view of a socket component according to one or more embodiments of the present invention;

[0031] FIG6( b ) is a BB cross-sectional view of FIG6( a );

[0032] Figure 7 It is a schematic diagram of the structure of a fixing member according to one or more embodiments of the present invention.

[0033] Among them, 1. soft finger, 101. strain layer, 102. restriction layer, 103. wrapping layer; 2. gripper base, 201. connecting bracket, 202. fixing bracket, 203. first fixing part, 204. second fixing part, 205. socket part; 3. connecting rod. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0035] Embodiment 1:

[0036] This embodiment provides a multi-cavity soft finger, such as Figure 1 As shown, it includes a strain layer 101, a restriction layer 102 and a wrapping layer 103. At least two strain layers 101 are arranged side by side and wrapped by the wrapping layer 103 to form a multi-chamber structure soft finger 1 to increase the contact area with the object. The interior of the strain layer 101 is a cavity, and its cross section is trapezoidal. A stable structure is formed by splicing several trapezoidal strain layers 101 in sequence to enhance the stability of the robot gripping.

[0037] In this embodiment, three strain layers 101 are provided, and the inclined surfaces of adjacent strain layers 101 correspond to each other. A large trapezoidal structure is formed by the strain layers 101 , and the soft finger 1 itself has strong stability.

[0038] like Figure 2 As shown in Figures 3(a) and 3(b), one end of the strain layer 101 is a closed structure, and the closed end is the front end of the finger when grasping; the other end of the strain layer 101 is an open structure, and a socket component 205 can be installed at the open structure. The pipeline of the pneumatic device is connected through the socket component 205, and air is inflated into the cavity of the strain layer 101 to achieve positive or reverse bending.

[0039] Since the strain layer 101 is a trapezoid, the surface on one side corresponding to the short side of the trapezoid is a narrow end surface, and the restriction layer 102 is fixed on the narrow end surface; the restriction layer 102 is a flat plate structure, and is bonded to the narrow end surface of the strain layer 101 by a silicone adhesive. The material hardness of the restriction layer 102 is slightly higher than that of the strain layer 101. Under the same air pressure, the deformation of the restriction layer 102 is smaller than that of the strain layer 101, and the soft finger 1 bends toward the side of the restriction layer 102.

[0040] The open end of the strain layer 101 also needs to cooperate with the gripper base 2 , so the length of the restriction layer 102 should be smaller than that of the strain layer 101 , leaving a plug-in section for the strain layer 101 .

[0041] The wrapping layer 103 is provided with trapezoidal grooves corresponding to the strain layers 101 one by one, and the trapezoidal grooves are arranged alternately with the long side on top or the short side on top, and the strain layers 101 are combined into a whole through the wrapping layer 103. The wrapping layer 103 is provided with a number of hollow areas, which can reduce the resistance during bending. Figure 1In the direction shown, the top surface and both sides of the wrapping layer 103 are arranged with hollow areas, and a plurality of hollow grooves arranged in parallel are arranged in the hollow areas; the top surface of the wrapping layer 103 is the gripping surface of the soft finger 1.

[0042] The open end of the strain layer 101 extends out of the wrapping layer 103 by a certain length. At the same time, a protrusion is provided around the end of the wrapping layer 103 where the strain layer 101 extends out. The protrusion is also a trapezoidal structure, and the protrusion cooperates with the gripper base 2 to form a limit.

[0043] In this embodiment, the soft finger 1 is made of flexible material, wherein the strain layer 101 and the wrapping layer 103 are made of silicone rubber material. The two groups of silicone rubber materials A and B are poured into a container in a ratio of 1:1, and stirred in the form of drawing a number 8 using a craft stick to fully mix the materials and then poured into a 3D printed mold. After standing for 6 hours, the cured strain layer 101 and the wrapping layer 103 are peeled off from the mold. The restriction layer 102 is made of TPU material by a 3D printer; finally, the strain layer 101 and the restriction layer 102 are bonded together by a silicone adhesive and inserted into the wrapping layer 103.

[0044] The soft finger 1 of this embodiment is provided with a plurality of independent cavities, and the cavities are cross-arranged. Taking the three strain layers 101 as an example, the cross-sectional directions of the cavities of the strain layers 101 on both sides are consistent (the short side is on the top and the long side is on the bottom), and the cavities of the middle strain layer 101 are oriented in the opposite direction (the long side is on the top and the short side is on the bottom); when positive pressure is input to the cavities on both sides and negative pressure is input to the middle cavity at the same time, the three cavities drive the wrapping layer 103 to bend inwardly to achieve inward grasping; conversely, the three cavities drive the wrapping layer 103 to bend outwardly to achieve outward opening.

[0045] This embodiment combines multiple cavities together through the wrapping layer 103. This is because when the width increases, the area of ​​the cavity wall affected by the air pressure will also increase, resulting in severe radial expansion and inability to bend normally. This embodiment can flexibly adjust the air pressure required to be input into each cavity according to the shape of the object to be grasped. For example, when a circular culture dish needs to be grasped, negative pressure can be input into the middle cavity and positive pressure can be input into the cavities on both sides, so that the soft finger 1 is in contact with the culture dish (the straight line connecting the two contact points should pass through the center of the circle). Then slowly increase the air pressure of the cavities on both sides to ensure that the contact surfaces on both sides of the soft finger 1 are tightly fitted with the culture dish, thereby increasing the contact area with the culture dish, improving the load capacity, and being more stable during the grasping process.

[0046] Embodiment 2:

[0047] This embodiment provides a multi-cavity soft manipulator, including a gripper base 2 and at least two soft fingers 1 described in Embodiment 1. This embodiment takes two soft fingers 1 as an example for detailed description: the two soft fingers 1 are installed on the gripper base 2 to form a two-finger structure, such as Figure 4 As shown, one end of the two soft fingers 1 is plugged and fixed to the gripper base 2.

[0048] As shown in Figure 5, the gripper base 2 includes a connecting bracket 201 and a fixed bracket 202. The fixed brackets 202 are symmetrically installed at both ends of the connecting bracket 201, and the soft finger 1 is connected to the fixed bracket 202. The middle position of the connecting bracket 201 is connected to the connecting rod 3, and the assembly of the manipulator and the mechanical arm is realized through the connecting rod 3; according to the connection method of the mechanical arm, the corresponding connecting rod 3 can be replaced.

[0049] In order to facilitate disassembly and assembly, the fixing bracket 202 of this embodiment is butted against the end of the connecting bracket 201, and a trapezoidal insertion space for the soft finger 1 is formed between the two. Fixing members are respectively arranged on the upper and lower sides of the insertion space, namely, a first fixing member 203 and a second fixing member 204. The first fixing member 203 fixes the soft finger 1 on the gripper base 2 by covering the raised portion of the wrapping layer 103; the second fixing member 204 connects the connecting bracket 201 and the fixing bracket 202 together. The first fixing member 203 and the second fixing member 204 are both as shown in FIG. Figure 7 The trapezoidal structure shown.

[0050] like Figure 4 As shown in FIG6 , the mating ends of the soft finger 1 and the gripper base 2 are equipped with a socket component 205, and the socket component 205 corresponds to the strain layer 101 one by one; as shown in FIG6 (a) and FIG6 (b), a channel is provided in the socket component 205 that is connected to the internal cavity of the strain layer 101, and the channel is connected to the pipeline of the pneumatic device. A circle of silicone adhesive is applied around the protrusion at the bottom of the socket and connected to the tail of the strain layer 101. The socket can be connected to the air pipe to allow gas to enter the strain layer 101.

[0051] It should be noted that the pneumatic device is an existing structure and will not be described in detail here.

[0052] In this embodiment, the gripper base 2 and the connecting rod 3 are both made of PLA material by 3D printing.

[0053] The working principle of this embodiment is:

[0054] The soft finger 1 is inflated by a pneumatic device, and the gas enters the internal chamber of the strain layer 101 through the socket component 205, and bulges or contracts to both sides under the change of air pressure; when positive pressure is input, one side of the strain layer 101 bulges and deforms, and the soft finger 1 bends to the side of the restriction layer 102; when negative pressure is input, one side of the strain layer 101 contracts and deforms, and the soft finger 1 bends to the back side of the restriction layer 102.

[0055] Embodiment 3:

[0056] The present embodiment provides a working method of a multi-cavity soft manipulator, which is based on the soft manipulator described in Example 2, and inflates the soft finger 1 through a pneumatic device, wherein when positive pressure is input into the internal cavity of the strain layers 101 on both sides and negative pressure is input into the internal cavity of the middle strain layer 101 at the same time, the wrapping layer 103 is driven to bend inward to achieve inward grasping; when negative pressure is input into the internal cavity of the strain layers 101 on both sides and positive pressure is input into the internal cavity of the middle strain layer 101 at the same time, the wrapping layer 103 is driven to bend outward to achieve outward opening.

[0057] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-cavity soft finger, characterized in that: include: At least two strain layers are arranged side by side, the cross section of the strain layer is trapezoidal and the interior is a cavity; One end of the strain layer is closed, and the other end is used to input air pressure; a confinement layer, fixed to the narrow end surface of the strain layer; The wrapping layer is wrapped around the outside of all the strain layers and the restriction layers, so that the strain layers form a multi-chamber structure.

2. The multi-cavity soft finger according to claim 1, characterized in that: There are three strain layers, the cross sections of the strain layers on both sides are oriented in the same direction, and the cross sections of the middle strain layer are oriented in the opposite direction to the cross sections of the strain layers on both sides; The middle strain layer and the strain layers on both sides are input with opposite air pressures.

3. The multi-cavity soft finger according to claim 1, characterized in that: The restriction layer is a flat plate structure, which is bonded to the strain layer by an adhesive.

4. A multi-cavity soft finger according to claim 1 or 3, characterized in that: The material hardness of the restriction layer is higher than that of the strain layer, so that the soft finger bends toward the restriction layer side under the action of air pressure.

5. The multi-cavity soft finger according to claim 1, characterized in that: The wrapping layer is provided with a plurality of hollow areas.

6. A multi-cavity soft finger according to claim 1 or 5, characterized in that: A protrusion is provided at one end of the wrapping layer, and the protrusion is used to cooperate with the gripper base.

7. A multi-cavity soft manipulator, characterized in that: The invention comprises at least two soft fingers as described in any one of claims 1 to 6.

8. The multi-cavity soft manipulator according to claim 7, characterized in that: The soft finger is installed on the gripper base, and a socket component is installed at the matching end of the soft finger and the gripper base, and the socket component is used to connect the pneumatic device.

9. The multi-cavity soft manipulator according to claim 8, characterized in that: The gripper base comprises a connecting bracket, the connecting bracket is connected to a plurality of fixing brackets, and the soft fingers are plugged into the fixing brackets.

10. A working method of a multi-cavity soft manipulator according to any one of claims 7 to 9, characterized in that: The soft finger is inflated by a pneumatic device. When positive pressure is input into the internal cavity of the strain layer on both sides and negative pressure is input into the internal cavity of the middle strain layer at the same time, the wrapping layer is driven to bend inward, thereby achieving inward grasping. When negative pressure is input into the internal cavities of the strain layers on both sides and positive pressure is input into the internal cavity of the middle strain layer at the same time, the wrapping layer is driven to bend laterally outwards and open outwards.

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