Multi-knuckle intelligent pneumatic soft manipulator and preparation method thereof

Abstract

The invention relates to the technical field of soft robots, in particular to a multi-knuckle intelligent pneumatic soft manipulator and a preparation method thereof.The multi-knuckle intelligent pneumatic soft manipulator comprises two finger units which are arranged side by side, a grabbing space is formed when the finger units approach each other, and each finger unit comprises at least three soft fingers with knuckles connected in series; the limiting layer is installed on one side of the soft finger, the limiting layer and the soft finger form a closed air cavity corresponding to the knuckles, and the connecting function layer is arranged on the surface of the limiting layer; the all-fiber flexible pressure sensor is used for monitoring deformation gripping force at different knuckles when the multi-section type soft manipulator grabs a target object and comprises a plurality of ionic dielectric layers and electrode layers wrapping the ionic dielectric layers, and at least one ionic dielectric layer exists at each knuckle so as to monitor the deformation gripping force of each knuckle. Multi-mode grabbing of different objects can be achieved, pressure information of the grabbed objects can be sensed, and the dexterity and the intelligent degree of the mechanical arm are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soft robots, and in particular to a multi-joint intelligent pneumatic soft robot arm and a preparation method thereof. Background Art

[0002] Robotics technology has been widely used across various industrial sectors, significantly reducing labor costs and improving production efficiency. As the end-effector of a robotic system, the dexterity and intelligence of the manipulator directly impact the overall performance of the system. Soft manipulators, typically made of flexible materials, exhibit excellent compliance and continuous deformation capabilities, effectively protecting fragile objects. In recent years, with the rapid advancement of soft robotics technology, the application areas of soft manipulators have continued to expand, with enormous potential in areas such as human-machine interaction and the grasping of fragile objects.

[0003] However, current soft robotic arms still have the following key issues: (1) Limited by manufacturing technology, the structure of soft manipulators made of silicone materials is relatively simple. For example, common pneumatic soft manipulators can only achieve constant curvature bending of the entire finger, and most of them use a single drive source, resulting in a single grasping posture, insufficient grasping mode and flexibility; (2) The elastic modulus of soft manipulators is low and the deformation during grasping is large. It is still difficult to integrate flexible pressure sensors, or the integrated flexible pressure sensors are greatly affected by bending deformation, resulting in the low level of intelligence of current pneumatic soft manipulators.

[0004] (3) The multimodal grasping soft manipulator in the existing technology has a complex structure, and the difficulty of preparing and integrating sensors limits the intelligent development of soft manipulator grasping. Summary of the Invention

[0005] The present invention aims to at least improve one of the technical problems existing in the prior art. To this end, the present invention provides a multi-joint intelligent pneumatic soft manipulator and a method for preparing the same.

[0006] The technical solutions of the present invention are as follows: A multi-joint intelligent pneumatic soft manipulator, comprising two finger units arranged side by side, forming a grasping space when approaching each other, each finger unit comprising: Multi-segment soft robot, including: Soft fingers with at least three knuckles in series; a restriction layer, mounted on a side of the soft finger close to the grasping space, and forming closed air cavities corresponding to the knuckles with the soft finger, each of which is connected to an external air source; A connecting functional layer is provided on the surface of the restriction layer; The all-fiber flexible pressure sensor is used to monitor the deformation and gripping force of different knuckles of the multi-segment soft manipulator when grasping a target object. The sensor includes multiple ionic dielectric layers and electrode layers covering the ionic dielectric layers, wherein there is at least one ionic dielectric layer at each knuckle to monitor the deformation pressure of each knuckle.

[0007] In a possible technical solution, further, the surface of the electrode layer close to the restricting layer is a porous fiber structure, and liquid silicone is coated on the restricting layer to form the connecting functional layer. During the integrated casting process, the liquid silicone solution will penetrate into the porous fiber structure of the packaging layer of the electrode layer under the action of capillary force; the silicone that has not penetrated into the interior of the fiber maintains a homogeneous connection with the restricting layer, thereby ensuring the integration strength of the all-fiber flexible pressure sensor and the manipulator to form an integrated structure.

[0008] In a possible technical solution, further, the all-fiber flexible pressure sensor includes: A first electrode layer is installed on the surface of the connection function layer away from the restriction layer; A plurality of ionic dielectric layers are installed on a surface of the first electrode layer away from the connection functional layer; The second electrode layer is installed on the surface of the ionic dielectric layer away from the first electrode layer.

[0009] In a possible technical solution, further, the first electrode layer includes: A first electrode packaging layer is installed on the surface of the connection function layer; a first electrode adhesion layer, mounted on a surface of the first electrode packaging layer away from the connection function layer; The first liquid metal layer is installed on the surface of the first electrode adhesion layer away from the first electrode packaging layer, wherein the first liquid metal layer has a plurality of first liquid metal pattern layers adapted to the ionic dielectric layer.

[0010] In a possible technical solution, further, the second electrode layer includes: a second liquid metal layer installed on a surface of the ionic dielectric layer away from the first electrode layer, wherein the second liquid metal layer has a plurality of second liquid metal pattern layers adapted to the ionic dielectric layer; a second electrode adhesion layer, mounted on a surface of the second liquid metal layer away from the ionic dielectric layer; The second electrode packaging layer is installed on the surface of the second electrode adhesion layer away from the second liquid metal layer. The second electrode layer is packaged together with the ionic dielectric layer and the first electrode layer to obtain a full-fiber flexible pressure sensor.

[0011] A method for preparing a multi-joint intelligent pneumatic soft manipulator, comprising: The pretreated silica gel solution is poured into a mold of a multi-segment soft manipulator, and after demoulding, soft fingers and a restriction layer are obtained, and a layer of silica gel solution is applied to the bonding surface between the soft fingers and the restriction layer for bonding to obtain a multi-segment soft manipulator; preparing an electrode layer and an ionic dielectric layer in sequence, and bonding the electrode layer to both sides of the ionic dielectric layer to obtain a full-fiber flexible pressure sensor; Liquid silicone is coated on the restriction layer to form a connection function layer, which is connected to the electrode layer of the all-fiber flexible pressure sensor to obtain a multi-joint intelligent pneumatic soft manipulator.

[0012] In a possible technical solution, further, preparing the electrode layer includes the following contents: Obtaining thermoplastic polyurethane powder and dimethylacetamide solution in a first mass ratio, dissolving and uniformly mixing them to obtain a first precursor solution, namely, a thermoplastic polyurethane precursor solution; Depositing a first nanofiber membrane (pure thermoplastic polyurethane nanofiber membrane) using an electrospinning process according to the first precursor solution, and obtaining a first electrode packaging layer and a second electrode packaging layer based on the first nanofiber membrane (pure thermoplastic polyurethane nanofiber membrane); Obtaining graphene oxide powder and dissolving it in dimethylacetamide solution, adding thermoplastic polyurethane powder after ultrasonic treatment, and mixing them evenly to obtain a second precursor solution, namely, graphene oxide / thermoplastic polyurethane precursor solution; Depositing a second nanofiber membrane using an electrospinning process according to the second precursor solution (thermoplastic polyurethane precursor solution), and obtaining a first electrode adhesion layer and a second electrode adhesion layer based on the first nanofiber membrane; A liquid metal rectangular capacitor plate is obtained on the first electrode adhesion layer by a screen printing process, and is filled with gallium-based liquid metal to obtain a first liquid metal layer; A liquid metal rectangular capacitor plate is obtained on the second electrode adhesion layer by adopting a screen printing process, and is filled with gallium-based liquid metal to obtain a second liquid metal layer.

[0013] In a possible technical solution, further, preparing the ionic dielectric layer includes the following: Obtaining polyvinylidene fluoride-hexafluoropropylene copolymer particles and dissolving them in dimethylacetamide solution, mixing them evenly, and then adding ion gel solution and stirring to obtain a third precursor solution; The third precursor solution (thermoplastic polyurethane precursor solution) is deposited by an electrostatic spinning process to obtain a third nanofiber membrane, and an ionic dielectric layer is obtained based on the third nanofiber membrane.

[0014] In a possible technical solution, further, the size of the liquid metal rectangular capacitor plate is 3mm×3mm, and the gallium-based liquid metal includes gallium, indium, and tin, among which the gallium-indium-tin liquid metal has both high conductivity and ductility, which can ensure the stability of the performance of the full-fiber pressure sensor during deformation.

[0015] In a possible technical solution, further, the electrospinning process parameters are controlled to meet the following conditions, including: electrospinning voltage of 7KV, syringe flow rate of 100ul / h, spinning distance of 80cm, and spinning temperature of 25°C, so as to ensure that nanofibers with uniform size and fiber pore structure can be obtained continuously and stably.

[0016] Compared with existing soft manipulators, the multi-joint intelligent pneumatic soft manipulator according to the present invention has the following advantages: The present invention integrates a full-fiber flexible pressure sensor on a multi-segment intelligent soft manipulator. Specifically, a full-fiber flexible pressure sensor containing an ion dielectric layer is bonded to each soft knuckle. This can achieve multimodal grasping of different objects and sense the pressure information of the grasped objects, thereby improving the dexterity and intelligence of the manipulator. The present invention solves the integration problem of the manipulator and the flexible pressure sensor by cleverly applying a porous fiber structure between the multi-segment soft manipulator and the all-fiber flexible pressure sensor, effectively reducing the impact of the manipulator's bending deformation on the sensor performance.

[0017] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 2 is a schematic structural diagram of a multi-joint intelligent pneumatic soft manipulator according to an embodiment of the present invention; Figure 2 Schematic diagram of a full-fiber flexible pressure sensor for a multi-joint intelligent pneumatic soft manipulator according to an embodiment of the present invention; Figure 3 2. It is a schematic structural diagram of the connection between a multi-segment soft manipulator and a full-fiber flexible pressure sensor according to an embodiment of the present invention; Figure 4 Schematic diagram of various grasping modes of a multi-segment soft manipulator according to an embodiment of the present invention; Figure 5 This is a diagram showing the experimental results of the three-segment soft manipulator with different joints driven individually and fully; Figure 6 3. This is a diagram showing the experimental results of flexible intra-finger manipulation achieved by a multi-segment soft manipulator according to an embodiment of the present invention; Figure 7 is a sensitivity curve diagram of the all-fiber flexible pressure sensor according to an embodiment of the present invention; Figure 8 is a capacitance curve diagram of the all-fiber flexible pressure sensor when the multi-segment soft manipulator is bent without load according to an embodiment of the present invention; Figure 9 is a capacitance response curve diagram of the all-fiber flexible pressure sensor when the multi-segment soft manipulator according to an embodiment of the present invention grasps an object; Figure 10 This is a graph showing the capacitance output of the all-fiber flexible pressure sensors integrated at the proximal, middle, and distal joints of the multi-segment soft manipulator according to an embodiment of the present invention when performing intra-finger manipulation; Reference numerals: Multi-segment soft manipulator 1, soft finger 11, restriction layer 12; Connectivity layer 2; All-fiber flexible pressure sensor 3, first electrode layer 31, ionic dielectric layer 32, second electrode layer 33 First electrode packaging layer 311, first electrode adhesion layer 312, first liquid metal layer 313; A second liquid metal layer 331 , a second electrode adhesion layer 332 , and a second electrode packaging layer 333 . DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] It should be noted that when an element is referred to as being “fixed to” another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] In the specification, claims, and accompanying drawings of this application, the terms "first," "second," "third," and the like are used to distinguish different objects and are not used to describe a particular order. Furthermore, the terms "including," "comprising," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a list of steps or elements may be included, or alternatively, steps or elements not listed may be included, or other steps or elements may be included that are inherent to the process, method, product, or apparatus.

[0024] The present invention aims to address the inadequate dexterity and intelligence of existing soft manipulators by proposing a multi-joint intelligent pneumatic soft manipulator. This utilizes a multi-segment, independently driven structure and an integrated all-fiber pressure sensor to enrich the manipulator's grasping modes for various objects, improving the flexibility of traditional soft manipulators. Furthermore, the manipulator's ability to sense pressure and identify objects is ensured, thereby enhancing the manipulator's intelligence. For more information, please refer to the following examples: Example 1 like Figures 1 to 10 As shown, this embodiment provides a multi-joint intelligent pneumatic soft manipulator, which includes two finger units arranged side by side, forming a grasping space when approaching each other, and each finger unit includes: The multi-segment soft manipulator 1 is made of flexible silicone material and includes: A soft finger 11 with at least three joints connected in series; The restriction layer 12 is installed on the side of the soft finger 11 close to the grasping space, and forms a closed air cavity corresponding to the finger joints with the soft finger 11. Each closed air cavity is connected to an external air source, forming a multi-stage structure with independent control. Different objects can be driven by different combinations of finger joints to produce multi-mode grasping control methods; A connecting functional layer 2 is provided on the surface of the restriction layer 12; The all-fiber flexible pressure sensor 3 is used to monitor the deformation gripping force at different knuckles of the multi-segment soft manipulator 1 when grasping a target object. It includes multiple ionic dielectric layers 32 and electrode layers covering the ionic dielectric layers 32, wherein there is at least one ionic dielectric layer 32 at each knuckle to monitor the deformation gripping force of each knuckle.

[0025] It should be noted that, in this embodiment, the soft finger 11 can be but is not limited to a three-joint structure. As some embodiments of the present invention, the soft finger 11 is a deformable layer, including a proximal joint C, a middle joint B and a distal joint A, wherein the joint close to the robotic arm is the proximal joint C; the restricting layer 12 is a flat plate structure, which forms a multi-joint closed chamber with the soft finger 11 after bonding and packaging, and is also used to integrate the all-fiber flexible pressure sensor 3.

[0026] It should be noted that in this embodiment, the multi-joint closed chamber formed by the soft finger 11 and the restriction layer 12 will produce different degrees of bending deformation under the action of air pressure. The deformation degree of the restriction layer 12 will be smaller than that of the soft finger 11, so that the multi-segment soft manipulator 1 will bend toward the side of the all-fiber flexible pressure sensor 3, thereby generating a grasping action.

[0027] It should be noted that, in this embodiment, the surface of the electrode layer close to the restricting layer 12 is a porous fiber structure, and liquid silicone is coated on the restricting layer 12 to form the connecting functional layer 2. During the integrated casting process, the liquid silicone solution will penetrate into the porous fiber structure of the packaging layer of the electrode layer under the action of capillary force; the silicone that has not penetrated into the interior of the fiber maintains a homogeneous connection with the restricting layer 12, thereby ensuring the integration strength of the all-fiber flexible pressure sensor and the manipulator to form an integrated structure.

[0028] It should be noted that, in this embodiment, the all-fiber flexible pressure sensor 3 adopts an ion capacitance pressure sensor, uses a porous nanofiber membrane to construct the substrate and intermediate dielectric layer of the capacitance pressure sensor, and uses liquid metal as a conductive electrode, specifically including: A first electrode layer 31 is installed on the surface of the connection function layer 2 away from the restriction layer 12; A plurality of ionic dielectric layers 32 are installed on a surface of the first electrode layer 31 away from the connection function layer 2; The second electrode layer 33 is installed on a surface of the ionic dielectric layer 32 away from the first electrode layer 31 .

[0029] It should be noted that, in this embodiment, the first electrode layer 31 includes: A first electrode packaging layer 311 is installed on the surface of the connection function layer 2; A first electrode adhesion layer 312 is installed on a surface of the first electrode packaging layer 311 away from the connection function layer 2; The first liquid metal layer 313 is installed on the surface of the first electrode adhesion layer 312 away from the first electrode packaging layer 311 , wherein the first liquid metal layer 313 has a plurality of first liquid metal pattern layers adapted to the ionic dielectric layer 32 .

[0030] The second electrode layer 33 includes: a second liquid metal layer 331 mounted on a surface of the ionic dielectric layer 32 away from the first electrode layer 31 , wherein the second liquid metal layer 331 comprises a plurality of second liquid metal pattern layers adapted to the ionic dielectric layer 32 ; A second electrode adhesion layer 332 is installed on the surface of the second liquid metal layer 331 away from the ionic dielectric layer 32; The second electrode packaging layer 333 is installed on the surface of the second electrode adhesion layer 332 away from the second liquid metal layer 331. The second electrode layer 33 is packaged together with the ionic dielectric layer 32 and the first electrode layer 31 to obtain a full-fiber flexible pressure sensor 3.

[0031] It should be noted that, in this embodiment, the first electrode adhesion layer 312 and the second electrode adhesion layer 332 are made of a flexible composite material with good stretchability, and chemical bonds are added to their surface through a modification process to enhance the wetting effect of the liquid metal on the electrode adhesion layer; as an embodiment of the present invention, a composite nanofiber membrane is preferably used, but is not limited to a composite nanofiber membrane, typically a thermoplastic polyurethane TPU to which graphene oxide GO is added, and then a GO / TPU composite nanofiber membrane is obtained by an electrospinning process, wherein the introduced GO contains a large number of -OH functional groups, which form hydrogen bonds with the liquid metal oxide layer, thereby improving the wetting effect of the liquid metal on the GO / TPU composite nanofiber membrane.

[0032] It should be noted that, in this embodiment, the ionic dielectric layer 32 is a composite nanofiber membrane mixed with ionic liquid, and the ions rich therein form a nanoscale "double electric layer" with the electrons in the electrode layer, which greatly improves the sensitivity of the flexible capacitive pressure sensor.

[0033] It should be noted that in this embodiment, the elastic modulus of the multi-segment soft manipulator 1, the connecting functional layer 2 and the all-fiber flexible pressure sensor are of comparable magnitude to ensure that when the multi-joint intelligent pneumatic soft manipulator performs a grasping task, the degree of deformation is comparable and no destructive behaviors such as delamination, slippage, and wrinkling will occur.

[0034] like Figure 4 The figure shows a schematic diagram of various grasping modes of a multi-segment soft manipulator. The multi-joint intelligent pneumatic soft manipulator of this embodiment can complete a variety of grasping modes by combining different segments. The multi-joint intelligent pneumatic soft manipulator of this embodiment was tested in a multi-modal grasping experiment, including "single proximal joint drive", "single middle joint drive", "single distal joint drive", "proximal joint and middle joint drive", "proximal joint and distal joint drive", "middle joint and distal joint drive" and "all joints coordinated drive". The results are shown in Figure 2. Figure 5 The following diagrams show the experimental results of individual and full actuation of different phalanges of the three-segment soft manipulator. The following diagrams show, from left to right, the experimental test results of "single proximal phalange actuation," "single middle phalange actuation," "single distal phalange actuation," and "coordinated actuation of all phalanges" for the multi-segment soft manipulator. These test results demonstrate that each phalange of the multi-segment soft manipulator can be actuated separately, allowing for a richer range of actuation options through various combinations of modes.

[0035] Example 2 This embodiment provides a method for preparing a multi-joint intelligent pneumatic soft manipulator, which is used to prepare the multi-joint intelligent pneumatic soft manipulator as in Example 1, and includes: S1: pouring the pretreated silicone solution into a mold of a multi-segment soft manipulator, demoulding to obtain soft fingers and a restriction layer, applying a layer of silicone solution on the bonding surface between the soft fingers and the restriction layer for bonding to obtain a multi-segment soft manipulator; S2: preparing an electrode layer and an ionic dielectric layer in sequence, and bonding the electrode layer to both sides of the ionic dielectric layer to obtain a full-fiber flexible pressure sensor; S3: Liquid silicone is coated on the restriction layer to form a connection function layer, which is connected to the electrode layer of the all-fiber flexible pressure sensor to obtain a multi-joint intelligent pneumatic soft manipulator.

[0036] It should be noted that in this embodiment, S1 specifically includes: using 3D printing technology to obtain the required casting mold, which is divided into a restrictive layer mold and a deformable layer mold. A silicone solution (Dragon-skin) is prepared by mixing the original silicone components, A:B, in a mass ratio of 1:1. After thorough stirring, the silicone solution is vacuum-treated in a vacuum drying oven for 3 minutes to remove bubbles. The solution is then poured into the prepared mold, heated to 80°C, and held at this temperature for 3 hours before demolding to obtain the deformable layer and restrictive layer, respectively. Finally, a layer of liquid Dragon-skin silicone solution is applied to the bonding surfaces of the two layers for bonding. The solution is then heated to 80°C and held at this temperature for 2 hours to obtain a complete multi-jointed intelligent pneumatic soft manipulator.

[0037] It should be noted that, in this embodiment, in S2, preparing the electrode layer includes the following: A thermoplastic polyurethane (TPU) powder and a dimethylacetamide (DMAC) solution are obtained and dissolved and mixed uniformly in a first mass ratio to obtain a first precursor solution, i.e., a thermoplastic polyurethane precursor solution; Depositing a first nanofiber membrane (pure thermoplastic polyurethane nanofiber membrane) using an electrospinning process according to the first precursor solution, and obtaining a first electrode packaging layer and a second electrode packaging layer based on the first nanofiber membrane (pure thermoplastic polyurethane nanofiber membrane); Specifically, in this embodiment, TPU powder and dimethylacetamide solution (DMAC) are mixed in a mass ratio of 0.45:1. After ensuring that the TPU is fully dissolved, the solution is stirred with an electromagnetic stirrer at room temperature for 24 hours to obtain a TPU precursor solution. The pure TPU nanofiber membrane is deposited by an electrospinning process. The electrospinning voltage is 12KV, the syringe flow rate is 300ul / h, the spinning distance is 120cm, and the spinning temperature is 25°C.

[0038] Obtaining graphene oxide powder and dissolving it in dimethylacetamide solution, adding thermoplastic polyurethane powder after ultrasonic treatment, and mixing them evenly to obtain a second precursor solution, namely, graphene oxide / thermoplastic polyurethane precursor solution; Depositing a second nanofiber membrane using an electrospinning process according to the second precursor solution (thermoplastic polyurethane precursor solution), and obtaining a first electrode adhesion layer and a second electrode adhesion layer based on the first nanofiber membrane; Specifically, in this embodiment, the first and second electrode adhesion layers utilize a graphene oxide (GO) / TPU nanofiber composite membrane, prepared via an electrospinning process. The GO / TPU precursor solution is prepared via electrospinning using a mass ratio of 1:0.45:0.025 of DMAC:TPU:GO. GO powder is dissolved in a DAMC solution and ultrasonically treated for 30 minutes before adding TPU powder. The resulting solution is stirred at room temperature using an electromagnetic stirrer for 24 hours. Finally, the GO / TPU nanofiber composite membrane is deposited via electrospinning at a voltage of 10 kV, a syringe flow rate of 200 μl / h, a spinning distance of 100 cm, and a spinning temperature of 25°C.

[0039] A liquid metal rectangular capacitor plate is obtained on the first electrode adhesion layer by a screen printing process, and is filled with gallium-based liquid metal to obtain a first liquid metal layer; A liquid metal rectangular capacitor plate is obtained on the second electrode adhesion layer by a screen printing process, and is filled with gallium-based liquid metal to obtain a second liquid metal layer; Specifically, in this embodiment, gallium-based liquid metal is selected for the first liquid metal layer and the second liquid metal layer, and the mass ratio of gallium:indium:tin is 0.68:0.215:0.1; a 3mm×3mm liquid metal rectangular capacitor plate is prepared on the GO / TPU nanofiber composite membrane by screen printing process, which is used to fill the gallium-based liquid metal to form the first liquid metal layer and the second liquid metal layer.

[0040] It should be noted that, in this embodiment, in S2, preparing the ionic dielectric layer includes the following: Obtaining polyvinylidene fluoride-hexafluoropropylene copolymer particles and dissolving them in dimethylacetamide solution, mixing them evenly, and then adding ion gel solution and stirring to obtain a third precursor solution; The third precursor solution (thermoplastic polyurethane precursor solution) is deposited by an electrostatic spinning process to obtain a third nanofiber membrane, and an ionic dielectric layer is obtained based on the third nanofiber membrane.

[0041] Specifically, in this embodiment, the ionic dielectric layer utilizes a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) / 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFIS]) composite ionic fiber membrane, fabricated via an electrospinning process. PVDF-HFP particles were dissolved in a DMAC solution and stirred at room temperature for 12 hours using an electromagnetic stirrer. Afterward, an [EMIM][TFIS] ion gel solution was added and stirred for an additional 12 hours to produce a PVDF-HFP / [EMIM][TFIS] precursor solution with a mass ratio of DMAC:PVDF:[EMIM][TFIS] = 1:0.2:0.2. Finally, the PVDF-HFP / [EMIM][TFIS] nanofiber membrane was deposited via electrospinning at a voltage of 7 kV, a syringe flow rate of 100 μl / h, a spinning distance of 80 cm, and a spinning temperature of 25°C.

[0042] In this embodiment, a specific preparation process of a multi-joint intelligent pneumatic soft manipulator is provided, including the following specific steps: Step 1: Prepare the deformation layer and the restriction layer by integrated casting, apply a layer of Dragon-skin silicone solution on the bonding interface between the two, heat it to 80°C and keep it warm for 3 hours to obtain a multi-segment soft manipulator for backup.

[0043] Step 2: Obtain PVDF-HFP / [EMIM][TFIS] nanofiber membrane by electrospinning. Cut a 3 mm × 3 mm square as the ionic dielectric layer for subsequent use. The detailed working conditions of the electrospinning process are as described above, and the spinning time is 2 h.

[0044] Step 3: A pure TPU nanofiber membrane was obtained by electrospinning for 2 hours as the first electrode packaging layer, a GO / TPU composite nanofiber membrane was obtained by electrospinning for 1 hour on the pure nanofiber membrane as the first electrode adhesion layer, and a 3mm×3mm square liquid metal pattern was prepared on the GO / TPU composite nanofiber membrane by screen printing as the first liquid metal layer.

[0045] Step 4: Place the prepared 3 mm×3 mm PVDF-HFP / [EMIM][TFIS] nanofiber composite membrane on top of the first liquid metal layer pattern.

[0046] Step 5: Prepare a thin layer of GO / TPU composite nanofiber membrane using electrospinning process, and then prepare a 3 mm × 3 mm square liquid metal pattern as the second liquid metal layer on top of the GO / TPU composite nanofiber membrane using screen printing process.

[0047] Step 6: Electrospinning was performed on the GO / TPU composite nanofiber membrane for 1 hour to obtain a GO / TPU composite nanofiber membrane as the second electrode adhesion layer, and then electrospinning was performed on the GO / TPU composite nanofiber membrane for 2 hours to obtain a pure TPU nanofiber membrane as the second electrode packaging layer to complete the preparation of the full-fiber flexible pressure sensor.

[0048] Step 7: Apply a layer of Dragon-skin silicone solution on the bonding interface between the multi-segment soft manipulator and the all-fiber flexible pressure sensor. After natural curing, the integration of the multi-segment soft manipulator and the all-fiber flexible pressure sensor is completed to obtain a multi-joint intelligent pneumatic soft manipulator with pressure sensing capability.

[0049] It should be noted that during the curing process in this embodiment, the liquid Dragon-skin silicone solution will penetrate into the porous first electrode packaging layer under the action of capillary force, thereby realizing the in-situ integration of the multi-segment soft manipulator and the all-fiber flexible pressure sensor.

[0050] Compared with existing soft manipulators, the multi-joint intelligent pneumatic soft manipulator according to the present invention has the following advantages: The present invention integrates a full-fiber flexible pressure sensor on a multi-segment soft manipulator. Specifically, a full-fiber flexible pressure sensor containing an ion dielectric layer is bonded to each soft finger joint. This can achieve multimodal grasping of different objects and sense the pressure information of the grasped objects, thereby improving the dexterity and intelligence of the manipulator. The present invention solves the integration problem of the manipulator and the flexible pressure sensor by cleverly applying a porous fiber structure between the multi-segment soft manipulator and the all-fiber flexible pressure sensor, effectively reducing the impact of the manipulator's bending deformation on the sensor.

[0051] Example 3 Based on the above embodiments, this embodiment provides a control method for a multi-joint intelligent pneumatic soft manipulator to carry out multi-modal grasping experimental tests of the manipulator. Furthermore, after completing the grasping of the target object (taking a target ball as an example), it is still possible to achieve intra-finger operation by adjusting the air pressure, change the posture of the grasped object, and improve the flexibility of the manipulator.

[0052] Three multi-segment soft manipulators are mounted on a fixed base to construct an intelligent soft manipulator. Each enclosed air cavity is connected to an external air source, and the control valves located in the air path of each enclosed air cavity are linked by a controller. The control method of the multi-joint intelligent pneumatic soft manipulator includes the following contents: Obtain the air pressure in the closed air cavity of each knuckle in real time; Based on the air pressure of each knuckle, the corresponding grasping strategy is executed, and the grasping strategy includes the following multiple grasping posture switches, such as Figure 6 As shown: 1. When the air pressure input to the air cavity at the proximal phalanx is 50 kPa, and the air pressure input to the air cavity at the middle and distal phalanx is not, the soft manipulator as a whole presents a "pinching" grasping posture; Second, when the air pressure input to the air cavities at the proximal, middle, and distal phalanges is 50 kPa, the soft manipulator as a whole assumes a "full grip" grasping posture, and the position of the target ball also rises as the grasping posture changes; 3. The air pressure in the proximal and distal phalanges remains constant, while the air pressure in the middle phalanges is zero. The soft manipulator assumes a "half-grip" grasping posture, and the position of the target ball remains unchanged. Fourth, the air pressure in the distal phalanx remains unchanged. After the air pressure in the middle phalanx is adjusted to zero, the air pressure in the proximal phalanx is reduced to 30 kPa. The soft manipulator assumes a "hook" grasping posture. At this time, the position of the target ball is lower than that corresponding to the "half-grip" grasping posture. Fifth, the air pressure in the proximal knuckle cavity is increased to 50 kPa, and the air pressure in the distal knuckle cavity is adjusted to zero. The soft manipulator again assumes the "pinching" grasping posture. At this time, the position of the target ball is lower than the position corresponding to the "hook" grasping posture, but is the same as the position corresponding to the previous grasping posture "pinching". It should be noted that the 50 kPa in this embodiment is only the optimal value for this application and is not intended to limit the scope of protection of this application.

[0053] The performance of the all-fiber flexible pressure sensor of this application was tested. The results are as follows Figure 7 The figure shows the sensitivity curve of the all-fiber flexible pressure sensor prepared in the embodiment of the present invention. The curve consists of two stages, in which the sensitivity of the sensor in the first stage is 1.58KPa. -1 , the second stage sensitivity is 1Kpa -1 .

[0054] The all-fiber flexible pressure sensor prepared in this example was integrated into the surface of a multi-segment soft robot, and then the capacitance response of the sensor was tested when the pneumatic soft robot finger was empty and in contact with an object. Figure 8 The figure shows the capacitance curve of the full-fiber flexible pressure sensor when the manipulator is bent without load. It is found that the capacitance value of the sensor increases from 5.8pF to 13.2pF when the finger is bent and deformed. This is mainly because the bending deformation affects the structure of the ionic capacitance pressure sensor, resulting in a change in capacitance value. Figure 9The figure shows the capacitance curve of the all-fiber flexible pressure sensor when the manipulator contacts an object. It is found that when the finger bends and deforms, the sensor capacitance increases from 5.8pF to 120pF, far exceeding the effect of the manipulator's bending deformation. This comparison shows that the integrated all-fiber flexible pressure sensor is less affected by mechanical bending deformation. Furthermore, the experiment found that the capacitance response value of the sensor remained unchanged during each cycle, both when unloaded and when in contact with an object, indicating effective sensor integration. This is also due to the liquid silicone's ability to penetrate the porous fiber structure to form a stable interface connection, ensuring the integration strength of the all-fiber flexible pressure sensor and the multi-segment soft manipulator.

[0055] This embodiment provides a specific implementation case, which completes the finger operation according to the above grasping strategy, and records the capacitance response of the integrated full-fiber flexible pressure sensor of the proximal phalanx, middle phalanx, and distal phalanx respectively. The results are as follows: Figure 10 As shown, in Figure 10 (a) is the capacitance response change diagram of the distal knuckle during the grasping process. Figure 10 (b) shows the capacitance response change at the middle finger joint during the grasping process. Figure 10 (c) in the figure shows the change in capacitance response at the proximal knuckle during the grasping process. Figure 10 The figure shows the changes in the object's posture over time as the pressure on each knuckle of the manipulator changes during a complete grasping process, including: During the 10s to 30s stage, the proximal and middle phalanges input controlled air pressure, while the distal phalanges do not. At this point, the distal phalanges are in contact with the grasped object and are subject to pressure. Furthermore, the capacitance of the full-fiber pressure sensor at the distal phalanges increases with the increase in controlled air pressure at the proximal and middle phalanges. During the 30s to 50s stage, air pressure is input to the proximal and distal phalanges, but no air pressure is input to the middle phalanges. During this period, the grasped object continues to rise, and the grasped object simultaneously contacts the middle and distal phalanges. Under the action of pressure, the capacitance of the full-fiber pressure sensors at the middle and distal phalanges increases continuously with the increase of the air pressure at the proximal and distal phalanges. During the 50s to 70s stage, the air pressure input to the proximal phalanx decreases, the air pressure input to the middle phalanx stops, and the air pressure input to the distal phalanx increases. The grasped object continues to rise. At this time, the grasped object partially breaks away from the distal phalanx and comes into contact with the proximal phalanx. Under the action of pressure, the capacitance of the full-fiber pressure sensor at the middle and proximal phalanx increases, while the pressure on the distal phalanx decreases, causing the capacitance of the full-fiber pressure sensor at the distal phalanx to decrease. The grasping is completed after 70 seconds, and the pressure on each knuckle gradually clears.

[0056] It can be seen that during the grasping process, this multi-joint intelligent pneumatic soft robot arm with pressure sensing ability can accurately reflect the contact status of each joint with the grasped object and the dynamic changes in the pressure in real time through the changes in the capacitance of the full-fiber pressure sensor based on the air pressure control of each joint in different time periods, thereby continuously grasping the pressure changes of each joint during the grasping process and having excellent pressure sensing ability.

[0057] At the same time, the capacitance output of the all-fiber flexible pressure sensor that is not subjected to pressure remains stable, indicating that the sensor is not affected by the bending deformation of the manipulator.

[0058] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation to the invention.

[0059] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0060] Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Mentioning "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present embodiment application. The appearance of this phrase in various positions in the specification does not necessarily mean that they are all the same embodiments, nor are they independent or alternative embodiments that are mutually exclusive with other embodiments. It can be understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0061] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A multi-joint intelligent pneumatic soft manipulator, characterized in that: It includes two finger units arranged side by side, forming a gripping space when approaching each other, and each finger unit includes: Multi-segment soft manipulator (1), comprising: soft fingers with at least three joints in series (11); A restriction layer (12) is installed on one side of the soft finger (11) close to the grasping space, and forms a closed air cavity corresponding to the finger joint with the soft finger (11), and each closed air cavity is connected to an external air source; A connecting functional layer (2) is provided on the surface of the restriction layer (12); The all-fiber flexible pressure sensor (3) is used to monitor the deformation gripping force of different finger joints of the multi-segment soft manipulator (1) when grasping a target object, and comprises a plurality of ionic dielectric layers (32) and an electrode layer covering the ionic dielectric layer (32), wherein at least one ionic dielectric layer (32) is present at each finger joint to monitor the deformation gripping force of each finger joint.

2. The multi-joint intelligent pneumatic soft manipulator according to claim 1, characterized in that: The surface of the electrode layer close to the restriction layer (12) is a porous fiber structure, and liquid silicone is coated on the restriction layer (12) to form the connection function layer (2).

3. The multi-joint intelligent pneumatic soft manipulator according to claim 1, characterized in that: The all-fiber flexible pressure sensor (3) comprises: a first electrode layer (31) mounted on a surface of the connecting functional layer (2) away from the limiting layer (12); A plurality of ionic dielectric layers (32) are installed on a surface of the first electrode layer (31) away from the connection function layer (2); The second electrode layer (33) is installed on the surface of the ionic dielectric layer (32) away from the first electrode layer (31).

4. The multi-joint intelligent pneumatic soft manipulator according to claim 3, characterized in that: The first electrode layer (31) comprises: A first electrode packaging layer (311) is mounted on the surface of the connecting functional layer (2); a first electrode adhesion layer (312) mounted on a surface of the first electrode packaging layer (311) away from the connection function layer (2); A first liquid metal layer (313) is installed on the surface of the first electrode adhesion layer (312) away from the first electrode packaging layer (311), wherein the first liquid metal layer (313) has a plurality of first liquid metal pattern layers adapted to the ionic dielectric layer (32).

5. The multi-joint intelligent pneumatic soft manipulator according to claim 3, characterized in that: The second electrode layer (33) comprises: a second liquid metal layer (331) mounted on a surface of the ionic dielectric layer (32) away from the first electrode layer (31), wherein the second liquid metal layer (331) has a plurality of second liquid metal pattern layers adapted to the ionic dielectric layer (32); a second electrode adhesion layer (332) mounted on a surface of the second liquid metal layer (331) away from the ionic dielectric layer (32); The second electrode packaging layer (333) is installed on a surface of the second electrode adhesion layer (332) away from the second liquid metal layer (331).

6. A method for preparing a multi-joint intelligent pneumatic soft manipulator, characterized in that: include: The pretreated silica gel solution is poured into a mold of a multi-segment soft manipulator, and after demoulding, soft fingers and a restriction layer are obtained, and a layer of silica gel solution is applied to the bonding surface between the soft fingers and the restriction layer for bonding to obtain a multi-segment soft manipulator; preparing an electrode layer and an ionic dielectric layer in sequence, and bonding the electrode layer to both sides of the ionic dielectric layer to obtain a full-fiber flexible pressure sensor; Liquid silicone is coated on the restriction layer to form a connection function layer, which is connected to the electrode layer of the all-fiber flexible pressure sensor to obtain a multi-joint intelligent pneumatic soft manipulator.

7. The method for preparing a multi-joint intelligent pneumatic soft manipulator according to claim 6, characterized in that: Preparation of the electrode layer includes the following: Obtaining thermoplastic polyurethane powder and dimethylacetamide solution, dissolving and uniformly mixing them in a first mass ratio to obtain a first precursor solution; Depositing a first nanofiber membrane using an electrospinning process according to the first precursor solution, and obtaining a first electrode packaging layer and a second electrode packaging layer based on the first nanofiber membrane; Obtaining graphene oxide powder and dissolving it in dimethylacetamide solution, adding thermoplastic polyurethane powder after ultrasonic treatment, and mixing them evenly to obtain a second precursor solution; Depositing a second nanofiber membrane using an electrospinning process according to the second precursor solution, and obtaining a first electrode adhesion layer and a second electrode adhesion layer based on the first nanofiber membrane; A liquid metal rectangular capacitor plate is obtained on the first electrode adhesion layer by a screen printing process, and is filled with gallium-based liquid metal to obtain a first liquid metal layer; A liquid metal rectangular capacitor plate is obtained on the second electrode adhesion layer by adopting a screen printing process, and is filled with gallium-based liquid metal to obtain a second liquid metal layer.

8. The method for preparing a multi-joint intelligent pneumatic soft manipulator according to claim 6, characterized in that: The preparation of the ionic dielectric layer includes the following: Obtaining polyvinylidene fluoride-hexafluoropropylene copolymer particles and dissolving them in dimethylacetamide solution, mixing them evenly, and then adding ion gel solution and stirring to obtain a third precursor solution; A third nanofiber membrane is deposited from the third precursor solution using an electrostatic spinning process, and an ionic dielectric layer is obtained based on the third nanofiber membrane.

9. The method for preparing a multi-joint intelligent pneumatic soft manipulator according to claim 7, characterized in that: The size of the liquid metal rectangular capacitor plate is 3 mm×3 mm, and the gallium-based liquid metal includes gallium, indium, and tin.

10. The method for preparing a multi-joint intelligent pneumatic soft manipulator according to claim 8, characterized in that: The electrospinning process parameters are controlled to meet the following conditions, including: The electrospinning voltage was 7 KV, the syringe flow rate was 100 ul / h, the spinning distance was 80 cm, and the spinning temperature was 25 °C.

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