A soft drive and soft gripper based on annular cross fiber interference

Abstract

The present invention provides a soft actuator based on annular cross-fiber interference, and a soft gripper, the actuator comprising: an inner soft tube, a fiber line is arranged in the side wall, and a first vent hole is arranged in communication with the inside of the tube; a variable stiffness structure comprises two fiber units, the fiber unit comprises a base and a plurality of fiber bundles, each fiber bundle is connected to the base at only one end, and each fiber bundle is arranged at intervals around the edge of the base, and the bases of the two fiber units are respectively fixedly connected to the two ends of the inner soft tube, so that a fiber bundle of each fiber unit is inserted between the two fiber bundles of the other fiber unit; and an outer soft sleeve, a second vent hole is arranged in communication between the outer soft sleeve and the inner soft tube. Beneficial effects of the present invention: the variable stiffness structure inside the actuator can follow the extension of the actuator, effectively improving the stretching forming stability of the soft elongation actuator; it solves the problem of local cavities caused by the extension of the traditional particle interference variable stiffness, and has the characteristics of global variable stiffness.

Description

Technical Field

[0001] The present invention relates to the technical field of soft drive, and in particular to a soft drive based on annular cross fiber interference, and a soft gripper. Background Art

[0002] The soft actuator is the core actuator of the soft gripper and is of great significance to the performance improvement of the soft gripper. The soft actuator with extension function is one of the most common actuators, which can be used in soft grippers and provides a promising solution for adjusting the grasping range of the gripper. However, the soft extension actuator has difficulty maintaining the stability of its stretched shape under high loads. For example, when the soft gripper needs to grasp heavier and larger objects, due to the soft characteristics of the soft extension actuator, the load capacity is poor and it is difficult to resist the reverse force from the grasped object, which will cause unstable grasping.

[0003] In recent years, variable stiffness technology has been developed and is regarded as an effective way to solve the softness problem of soft actuators. There are two types of existing variable stiffness technologies, one is to change stiffness through the smart material method, and the other is to change stiffness through mutual extrusion between structures (commonly known as interference method). The former changes the molecular properties of the material itself by applying external stimuli such as light, electricity, and heat, thereby changing from a soft state to a hard state. The latter changes stiffness by gathering granular media, layered media, etc. in a thin film, and then applying negative pressure to compress the media.

[0004] However, the existing variable stiffness technology has great limitations when applied to elongation actuators. Whether it is the variable stiffness method of smart materials or the variable stiffness method of negative pressure interference, it is difficult to apply it to elongation actuators. This is because the variable stiffness material / variable stiffness structure itself is not stretchable and cannot be stretched as the elongation actuator is stretched. Taking the particle interference method as an example, when the particle interference structure is stretched, a cavity area will appear due to the stretching, and the global stiffness cannot be changed, that is, the variable stiffness function fails. The same is true for the layer interference method. Summary of the invention

[0005] In view of this, in order to solve the problem that the existing variable stiffness structure is difficult to apply to soft extension actuators, resulting in low hardness of the actuator during operation, prone to deformation and loose grasping, an embodiment of the present invention provides a soft actuator and a soft gripper based on annular cross fiber interference.

[0006] An embodiment of the present invention provides a software driver based on annular cross fiber interference, comprising:

[0007] An inner soft tube, with both ends closed, a spirally wound fiber line arranged in the side wall, and a first vent hole communicating with the interior of the inner soft tube;

[0008] A variable stiffness structure, which is sleeved on the outer periphery of the inner soft tube, comprises two fiber units, each of which comprises a base and a plurality of fiber bundles, each of which is connected to the base at only one end, and each of which is spaced around the edge of the base, and the bases of the two fiber units are respectively fixedly connected to the two ends of the inner soft tube, so that one fiber bundle of each fiber unit is inserted between two fiber bundles of the other fiber unit;

[0009] and an outer soft sleeve, which is sleeved on the outer periphery of the variable stiffness structure and is provided with a second vent hole, wherein the second vent hole communicates with the space between the outer soft sleeve and the inner soft tube.

[0010] Furthermore, the fiber bundles of each fiber unit are distributed on a circumference, and two fiber units are spliced ​​into a hollow cylinder.

[0011] Furthermore, the outer soft sleeve is a cylindrical tube with closed ends.

[0012] Furthermore, the inner soft tube comprises an inner tube body with openings at both ends, the outer soft sleeve comprises an outer tube body and two end covers, the inner side surfaces of the end covers are provided with raised connecting rings, the edge of each end cover is sealed connected to one end of the outer tube body, and each connecting ring is sealed connected to one end of the inner tube body.

[0013] Furthermore, the axes of the inner soft tube, the variable stiffness structure and the outer soft sleeve coincide with each other.

[0014] Furthermore, the base is an annular sheet, which is sleeved on one end of the inner soft tube and fixedly connected to the outer wall of the inner soft tube.

[0015] Furthermore, the inner soft tube and / or the outer soft sleeve are both made of silicone.

[0016] Furthermore, based on the above-mentioned soft driver based on annular cross-fiber interference, an embodiment of the present invention further provides a soft gripper, comprising the above-mentioned soft driver based on annular cross-fiber interference, and also comprising an outer shell, and two movable arms slidably connected to the two ends of the outer shell, wherein the driver is arranged in the outer shell, and the two ends of the outer soft cover are respectively connected to the two movable arms to drive the two movable arms to move relative to each other.

[0017] Furthermore, the movable arm includes a slider and a clamping claw connected to the slider, and the slider is slidably disposed in the housing.

[0018] Furthermore, a contact airbag is provided at the lower end of the clamping jaw.

[0019] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention are:

[0020] 1. A soft actuator based on annular cross-fiber interference of the present invention has a variable stiffness structure inside the actuator that can stretch along with the actuator, thereby effectively improving the stretching forming stability of the soft elongation actuator.

[0021] 2. The soft driver based on annular cross-fiber interference of the present invention solves the problem of local cavity caused by stretching in traditional particle interference variable stiffness / layer interference variable stiffness, and has the characteristic of global variable stiffness.

[0022] 3. The soft actuator based on annular cross-fiber interference of the present invention is universal and applicable to most soft extension actuators.

[0023] 4. The soft gripper of the present invention can automatically adjust the gripping distance to achieve a stable adjustment of the gripping range, and can effectively resist the reverse force of the object, thereby improving the stability of the soft gripper when adjusting the gripping distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a stereogram of a soft driver 100 based on annular cross fiber interference according to the present invention;

[0025] Figure 2 The invention is a kind of explosion of the soft drive 100 based on the annular cross fiber interference Figure 1 ;

[0026] Figure 3 The invention is a kind of explosion of the soft drive 100 based on the annular cross fiber interference Figure 2 ;

[0027] Figure 4 is a cross-sectional view of a soft driver 100 based on annular cross-fiber interference according to the present invention;

[0028] Figure 5 It is a three-dimensional diagram of a fiber unit;

[0029] Figure 6 is a bottom view of the fiber unit;

[0030] Figure 7 It is a schematic diagram of the movement of two fiber units when a soft actuator 100 based on annular cross fiber interference of the present invention is stretched;

[0031] Figure 8 It is a three-dimensional diagram of a soft gripper of the present invention;

[0032] Fig. 9 It is a stereogram of the movable arm;

[0033] Fig.10 It is a top view of a soft gripper of the present invention;

[0034] Fig.11 yes Fig.10 AA section diagram in .

[0035] In the figure: 100-soft drive based on annular cross-fiber interference, 1-outer soft sleeve, 2-inner soft tube, 3-variable stiffness structure, 4-outer tube body, 5-first ventilation hole, 6-second ventilation hole, 7-end cover, 8-fiber unit, 9-base, 10-fiber bundle, 11-connecting ring, 101-housing, 101a-slide groove, 102-movable arm, 102a-slider, 102b-clamping claw, 102c-convex strip, 102d-contact airbag. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the embodiments of the present invention will be further described below in conjunction with the accompanying drawings. The following is a preferred embodiment of the present invention, which is intended to provide a basic understanding of the present invention, but is not intended to confirm the key or decisive elements of the present invention or to limit the scope of protection.

[0037] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0038] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0039] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings. At the same time, it should be understood that for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" 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 a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Please refer to Figure 1 , 2, 3 and 4, an embodiment of the present invention provides a soft driver 100 based on annular cross-fiber interference, which is a cylindrical extension driver, mainly comprising an inner soft tube 2, a variable stiffness structure 3 and an outer soft sleeve 1 arranged in sequence from the inside to the outside.

[0042] The inner soft tube 2 is a cylindrical tube, and both ends of the inner soft tube 2 are kept closed to form a sealed space inside the inner soft tube 2. A spirally wound fiber line is provided inside the side wall of the inner soft tube 2, and the inner soft tube 2 is provided with a first vent hole 5 communicating with the inside thereof. The inner soft tube 2 can be inflated through the first vent hole 5, and when inflated, the fiber line can suppress the radial expansion of the inner soft tube 2, so that the inner soft tube 2 can only extend along the axial direction.

[0043] Generally, the inner soft tube 2 is made of silicone and is injection molded by silicone using an injection mold. When the inner soft tube 1 is injection molded, two injection moldings are performed successively, and the fiber line is evenly spirally wound on the surface of the semi-finished product of the previous injection molding, and then the next injection molding is performed to form the inner soft tube 2, and the fiber line is injection molded inside the side wall of the inner soft tube 2.

[0044] like Figure 3 and 4 As shown, the variable stiffness structure 3 is sleeved on the outer periphery of the inner soft tube 2, and the variable stiffness structure 3 is composed of two fiber units 8 arranged up and down, and the two fiber units 8 are respectively sleeved on the two ends of the inner soft tube 2 and fixedly connected with the two ends of the inner soft tube 2, and the two fiber units 8 are only in contact and can produce relative sliding. Specifically,

[0045] like Figure 5 and 6 As shown, each fiber unit 8 includes a base 9 and a plurality of fiber bundles 10, each fiber bundle 10 is connected to the base 9 at only one end and is freely arranged at the other end, and each fiber bundle 10 is arranged at intervals around the edge of the base 9. The base 9 is specifically an annular sheet, each fiber bundle 10 is arranged vertically relative to the base 9, and one end is bonded and fixedly connected to the edge of the base 9, so that each fiber bundle 10 of each fiber unit 8 is distributed on the circumference of the edge of the base 9.

[0046] The base 9 of each fiber unit 8 is sleeved on one end of the inner soft tube 2 and fixedly connected to the outer wall of the inner soft tube 2, so that the bases 9 of the two fiber units 8 are respectively fixedly connected to the two ends of the inner soft tube 2. At the same time, a fiber bundle 10 of each fiber unit 8 is inserted into the gap between the two fiber bundles 10 of another fiber unit 8, so that the two fiber units 8 are just spliced ​​into a hollow cylinder to form the variable stiffness structure 3, and the fiber bundles 10 of the two fiber units 8 are only in contact with each other without any obstruction.

[0047] Preferably, the fiber bundles 10 of each fiber unit 8 are evenly distributed on the circumference of the edge of the base 9. The number of the fiber bundles 10 can be flexibly set according to the diameter of the variable stiffness structure 3. For example, in this embodiment, the number of the fiber bundles 10 is four, and the four fiber bundles 10 are evenly distributed on the circumference of the edge of the base 9, and the circumferential angle corresponding to each fiber bundle 10 is 45°.

[0048] The fiber bundle 10 is composed of a plurality of fiber strips. When the variable stiffness structure is manufactured, the fiber strips of the fiber bundle 10 are directly 3D printed with soft rubber material using Polyjet 3D printing technology. The base 9 can be 3D printed using Polyjet 3D printing technology or can be manufactured using mold injection molding.

[0049] Continue as Figure 3 and 4 As shown, the outer soft sleeve 1 is sleeved on the periphery of the variable stiffness structure 3, and the two ends of the outer soft sleeve 1 are respectively connected to the two ends of the inner soft tube 2, and the outer soft sleeve 1 is provided with a second vent hole 6, and the second vent hole 6 communicates with the space between the outer soft sleeve 1 and the inner soft tube 2. The outer soft sleeve 1 is a cylindrical tube body with closed ends, and is also injection molded by silicone material. In order to make the extension of the inner soft tube 2 better drive the extension of the outer soft sleeve 1, the axes of the inner soft tube 2, the variable stiffness structure 3 and the outer soft sleeve 1 coincide.

[0050] In order to facilitate the assembly of the inner soft tube 2, the variable stiffness structure 3 and the outer soft sleeve 1, Figure 2 As shown, the inner soft tube 2 includes an inner tube body with openings at both ends, and the outer soft sleeve 1 includes an outer tube body 4 and two end covers 7. The inner side of the end cover 7 is provided with a raised connecting ring 11, and the edge of each end cover 7 is sealed and connected to one end of the outer tube body 4 by bonding, and each connecting ring 11 is embedded in one end of the inner tube body and then sealed and connected by bonding.

[0051] The first vent hole 5 is arranged at the center of one of the end caps 7 and communicates with one end of the inner tube body. The second vent hole 6 is arranged at the edge of one of the end caps 7. There may be a plurality of second vent holes 6, each of which communicates with the space between the inner wall of the outer soft sleeve 1 and the outer wall of the inner soft tube 2.

[0052] When the soft actuator 100 based on annular cross fiber interference is working, the inner soft tube 2 can be ventilated through the first vent hole 5, and the inner soft tube 2 can be stretched under the action of air pressure. Figure 7 Then, negative pressure is drawn into the outer soft cover 1 through the second vent hole 6 to harden the fiber bundles 10 of the two fiber units 8, thereby changing the overall stiffness of the actuator 100. This overcomes the problem that the variable stiffness material / variable stiffness structure itself has no stretchability and cannot stretch with the stretching of the elongation actuator.

[0053] In addition, based on the above-mentioned soft drive 100 based on annular cross fiber interference, the embodiment of the present invention further provides a soft gripper, such as Figure 8 As shown, the soft gripper includes the above-mentioned soft driver 100 based on annular cross fiber interference (not shown in the figure), and also includes a shell 101 and two movable arms 102 slidably connected to the two ends of the shell 101.

[0054] Specifically, Fig.10 and 11 As shown, the shell 101 is a hollow cuboid with openings at both ends, and inner walls are provided with slide grooves 101a near both ends.

[0055] like Fig. 9 and 11 As shown, the movable arm 102 includes a slider 102a and a clamping claw 102b connected to the slider 102a. The slider 102a is slidably disposed in the housing 101, and convex strips 102c are disposed on both sides of the slider 102a. Each slider 102a is mounted on one end of the housing 101, and the convex strips 102c of the slider 102a are inserted into the slide groove 101a, so that the slider 102a can slide in the housing 101.

[0056] The clamping jaw 102b is located below the housing 101. A clearance opening is provided at the bottom of the housing 101. The upper end of the clamping jaw 102b passes through the clearance opening and is connected to the slider 102a, so that the clamping jaw 102b can be driven by the slider 102a to move.

[0057] The driver 100 is disposed in the housing 101, specifically accommodated between the two sliders 102a in the housing 101, and the two ends of the outer software cover 1 of the driver 100 are respectively connected to the two movable arms 102. When the driver 100 is extended or retracted, it can drive the two sliders 102a to slide, thereby driving the two movable arms 102 to move relatively closer or farther away.

[0058] The lower end of the clamping jaw 102b is used to clamp an object. Preferably, a contact airbag 102d is provided at the lower end of the clamping jaw 102b, and the contact airbag 102d directly contacts the object to play a buffering role and prevent damage to the object.

[0059] The above-mentioned soft gripper is designed based on the design concept of bionic human hands, simulating the opening and closing posture of human fingers, and can flexibly grasp objects of various sizes and shapes. When grasping, we first inflate the inner soft tube 2 of the driver 100 to stretch the inner soft tube 2 and drive the two clamps 102b away, then deflate the inner soft tube 2 until the two clamps 102b clamp the object, and then vacuum the space between the outer soft sleeve 1 and the inner soft tube 2 to increase the stiffness of the fiber bundles 10 of the two fiber units 8, and then lift the object, which can resist the reverse force from the object to the grasping process, and has the beneficial effect of stable grasping.

[0060] In this article, the directional words such as front, back, top, and bottom involved are defined by the positions of the parts in the drawings and the positions of the parts relative to each other, just for the sake of clarity and convenience in expressing the technical solution. It should be understood that they are relative concepts and can change accordingly according to different ways of use and placement, and the use of the directional words should not limit the scope of protection claimed in this application.

[0061] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A software driver based on annular cross fiber interference, characterized in that: include: An inner soft tube, with both ends closed, a spirally wound fiber line arranged in the side wall, and a first vent hole communicating with the interior of the inner soft tube; A variable stiffness structure, which is sleeved on the outer periphery of the inner soft tube, comprises two fiber units, each of which comprises a base and a plurality of fiber bundles, each of which is connected to the base at only one end, and each of which is spaced around the edge of the base, and the bases of the two fiber units are respectively fixedly connected to the two ends of the inner soft tube, so that one fiber bundle of each fiber unit is inserted between two fiber bundles of the other fiber unit; and an outer soft sleeve, which is sleeved on the outer periphery of the variable stiffness structure and is provided with a second vent hole, wherein the second vent hole communicates with the space between the outer soft sleeve and the inner soft tube.

2. A software driver based on annular cross fiber interference as claimed in claim 1, characterized in that: The fiber bundles of each fiber unit are distributed on a circumference, and two fiber units are spliced ​​into a hollow cylinder.

3. A software driver based on annular cross fiber interference as claimed in claim 2, characterized in that: The outer soft sleeve is a cylindrical tube with closed ends.

4. A software driver based on annular cross fiber interference as claimed in claim 3, characterized in that: The inner soft tube comprises an inner tube body with openings at both ends, and the outer soft sleeve comprises an outer tube body and two end covers. The inner side surfaces of the end covers are provided with raised connecting rings, and the edge of each end cover is sealed and connected to one end of the outer tube body, and each connecting ring is sealed and connected to one end of the inner tube body.

5. A software driver based on annular cross fiber interference as claimed in claim 3, characterized in that: The axes of the inner soft tube, the variable stiffness structure and the outer soft sleeve coincide with each other.

6. A software driver based on annular cross fiber interference as claimed in claim 1, characterized in that: The base is an annular sheet, which is sleeved on one end of the inner soft tube and fixedly connected to the outer wall of the inner soft tube.

7. A software driver based on annular cross fiber interference as claimed in claim 1, characterized in that: The inner soft tube and / or the outer soft sleeve are both made of silicone.

8. A soft gripper, characterized in that: It comprises a soft driver based on annular cross fiber interference as described in any one of claims 1 to 7, and also comprises a shell, and two movable arms slidably connected to the two ends of the shell, wherein the driver is arranged in the shell, and the two ends of the outer soft cover are respectively connected to the two movable arms to drive the two movable arms to move relative to each other.

9. A soft gripper according to claim 8, characterized in that: The movable arm comprises a slider and a clamping claw connected to the slider, and the slider is slidably arranged in the shell.

10. A soft gripper according to claim 9, characterized in that: A contact air bag is provided at the lower end of the clamping jaw.

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