Artificial muscle imitating plant tendril, human-like arm and arm measurement method

Abstract

The present invention discloses an artificial muscle imitating plant tendrils, including an artificial muscle tendril body, the artificial muscle tendril body including a silicone skin, a paper-cut structure and a restriction layer, the paper-cut structure is sealed and installed inside the silicone skin, a flexible circuit is etched on the paper-cut structure, and the restriction layer is fixedly installed on the bottom of the silicone skin after pre-stretching. The present invention also discloses a human-like arm and a testing method thereof, the human-like arm includes a large arm unit, a small arm unit and the artificial muscle imitating plant tendrils, the artificial muscle roll is made by imitating plant tendrils with the help of the programmable characteristics of the flexible circuit etching and the embedded paper-cut structure. When the artificial muscle tendril contracts, it drives the small arm unit to rotate and lift the load-bearing part. The changes in the number of spiral turns and the pitch cause the inductance to change, and different bending angles correspond to different electrical signals. It can solve the problem that the existing artificial muscles and artificial arms cannot have both movement and perception capabilities at the same time.

Description

Technical Field

[0001] The invention relates to an artificial muscle and a humanoid arm and an arm measurement method, in particular to an artificial muscle imitating plant tendrils and a humanoid arm and an arm measurement method, belonging to the field of artificial muscle driving and sensing technology. Background Art

[0002] In order to give soft robots different functions, the driving forms of soft robots are diversified. Pneumatic actuation still attracts considerable attention in the field of soft robots because of its simple and fast actuation. Soft actuators composed of pneumatic grids, fiber reinforcements, films, woven structures, etc. have limitations in scalability, design flexibility and stability due to their manufacturing processes, which limits their application areas. In recent years, researchers have used programmable curing elastomers, programmable stretching, and origami technology to flexibly manufacture various soft robots. However, due to their lack of perception functions, the potential of soft robots has not been fully realized.

[0003] In order to complete certain specific tasks, soft robots need sensors to feedback their own movements and detect the external environment. However, the single function of these sensors limits the application scope of soft robots. In recent years, the focus has been on integrating multiple sensors on the outside of soft robots. These sensors often require multiple materials, structures and complex manufacturing processes. Since they are attached to the outside of soft robots, the sensors are easily affected by the external environment and interfere with the movement of soft robots. Although multi-material 3D printing technology has many advantages, there are still some problems in some aspects, such as material limitations, structural non-uniformity, complex software and control systems, and durability. In order to cope with these limitations, paper-cut structures have been widely used in the driving and sensing of soft robots because of their softness, customizability, low cost, and high controllability. However, soft robots prepared using paper-cut technology still face huge challenges in taking into account both movement and perception capabilities.

[0004] Based on the above, the invention patent with publication number CN116276939A and publication date June 23, 2023 discloses a fast-response thermally driven spiral-wound artificial muscle, which is composed of three layers of materials: inner, middle, and outer, which respectively play the role of supporting sensing, heat insulation, and driving. The supporting sensing layer mainly plays a supporting role for the structure, and materials with sensing properties can also be selected to play a sensing role. However, the document does not disclose the artificial muscle made by imitating the biological morphology of plant tendrils, nor does it mention how to achieve the integration of driving and sensing. Summary of the invention

[0005] The present invention aims to solve the problem that existing artificial muscles and artificial arms cannot have both movement and perception capabilities, and further proposes an artificial muscle imitating plant tendril and a human arm and an arm measurement method, which have integrated drive and perception, fast actuation and strong scalability.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] An artificial muscle imitating plant tendrils comprises an artificial muscle tendril body, wherein the artificial muscle tendril body comprises a silicone skin, a paper-cut structure and a restriction layer, wherein the paper-cut structure is sealed and installed inside the silicone skin, a flexible circuit is etched on the paper-cut structure, and the restriction layer is fixedly installed at the bottom of the silicone skin after pre-stretching, and is used for spirally extending the artificial muscle tendril body from the middle to both sides in the axial direction.

[0008] Furthermore, the silicone layer of the artificial muscle tendril is made of Ecoflex00-20 and Dragon skin10, the material of the paper-cut structure is PET, and a copper film is electroplated on the surface of the paper-cut structure.

[0009] A human-like arm comprises an upper arm unit, a lower arm unit and an artificial muscle imitating plant tendril, wherein the upper arm unit and the lower arm unit are connected by gap fit, and two sides of the artificial muscle tendril body are respectively fixedly connected to the upper arm unit and the lower arm unit.

[0010] Furthermore, the materials of the upper arm unit and the lower arm unit are both acrylic.

[0011] Furthermore, the upper arm unit includes a shoulder joint, an upper arm, a fixed upper arm rod and a movable upper arm rod. An upper arm positioning hole is opened on the upper arm. The shoulder joint is connected to one end of the upper arm through a clearance fit. The fixed upper arm rod is tightly connected to the upper arm through an interference fit. The movable upper arm rod is connected to the upper arm positioning hole on the upper arm through a clearance fit. One side of the artificial muscle tendril is fixedly installed on the movable upper arm rod.

[0012] Furthermore, the number of the upper arm positioning holes is several, and the several upper arm positioning holes are arranged on the upper arm at equal intervals along the same straight line.

[0013] Furthermore, the forearm unit includes an elbow joint, a forearm, a fixed forearm rod, a movable forearm rod and a weight-bearing piece. A forearm positioning hole is opened on the forearm. The elbow joint is respectively connected to one end of the forearm and the other end of the upper arm through clearance fit. The weight-bearing piece is fixedly connected to the other end of the forearm. The fixed forearm rod is tightly connected to the forearm through interference fit. The movable forearm rod is clearance fit connected to the forearm positioning hole on the forearm, and the other side of the artificial muscle tendril is fixedly mounted on the movable forearm rod.

[0014] Furthermore, the number of the forearm positioning holes is several, and the several forearm positioning holes are arranged on the forearm at equal intervals along the same straight line.

[0015] Furthermore, the length of the upper arm is greater than the length of the lower arm.

[0016] Furthermore, a U-shaped groove is provided on the forearm at the end side of the weight-bearing member, and the weight-bearing member and the forearm are detachably fixedly connected via the U-shaped groove.

[0017] A testing method for a human arm simulation comprises the following steps:

[0018] S1: Collect the electrical signals generated by the humanoid arm and transmit the signals to the computer through the measuring meter for display and recording;

[0019] S2: Use a professional camera to record the bending angle of the forearm;

[0020] S3: Based on the electrical signal output by S1 and the angle recorded by S2, the arm lifting angle is represented by inductance.

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

[0022] 1. The artificial muscle proposed by the present invention is made in the biological form of plant tendrils, has a high contraction ratio, a large actuation distance, and realizes the integration of drive and sensing. It adopts pneumatic actuation, has a fast actuation speed and high efficiency.

[0023] 2. The humanoid arm and its measurement method proposed by the present invention, when the artificial muscle tendrils are inflated, the recurved section rotates around the central axis to produce contraction, driving the forearm to rotate and lift the load-bearing piece. The angle of rotation of the forearm can be recorded by a professional camera, so by collecting the inductance values ​​at different rotation angles, the functional relationship between the forearm rotation angle and the inductance can be obtained. It has an ultra-long service life and extremely high stability, and can realize the detection of the humanoid arm picking up and placing objects, and has the advantages of self-driven sensing, high measurement accuracy and long service life.

[0024] 3. The present invention has the characteristics of miniaturization and integration, and can realize real-time monitoring of the humanoid arm picking up and placing objects while maintaining the integrity and functional integrity of the artificial muscle, providing a theoretical and experimental basis for the development of new self-driving and self-sensing artificial muscles. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of an embodiment of the artificial muscle imitating plant tendril of the present invention.

[0026] Figure 2 It is a structural schematic diagram of an implementation mode of the paper-cut structure of the present invention.

[0027] Figure 3 It is a schematic structural diagram of an implementation mode of the human body-mimicking arm of the present invention.

[0028] Figure 4It is a schematic flow chart of the testing method of the human body-mimicking arm of the present invention.

[0029] Figure 5 It is a relationship diagram between the rotation angle of the small arm unit and the inductance signal of the present invention.

[0030] Figure 6 This is a diagram showing the results of a durability test of the triboelectric variable-rigidity soft gripper state monitoring sensor of the present invention.

[0031] In the figure: 1. artificial muscle tendril; 11. silicone layer; 12. paper-cut structure; 13. restriction layer; 2. upper arm unit; 21. shoulder joint; 22. upper arm; 23. fixed upper arm rod; 24. movable upper arm rod; 221. upper arm positioning hole; 3. forearm unit; 31. elbow joint; 32. forearm; 33. fixed forearm rod; 34. movable forearm rod; 35. weight-bearing piece; 321. forearm positioning hole. DETAILED DESCRIPTION

[0032] In the description of the present invention, it should be noted that all directional indications (such as left, right, etc.) are 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. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0033] Specific implementation method 1: Combination Figure 1-6 To illustrate this embodiment, Figure 1 and Figure 2As shown, the artificial muscle imitating plant tendrils described in this embodiment includes an artificial muscle tendril 1 body, the artificial muscle tendril 1 body includes a silicone skin, a paper-cut structure 12 and a restriction layer 13, the paper-cut structure 12 is sealed and installed inside the silicone skin, a flexible circuit is etched on the paper-cut structure 12, and the restriction layer 13 is fixedly installed at the bottom of the silicone skin after pre-stretching, and is used to extend the artificial muscle tendril 1 body from the middle to both sides in a spiral shape in the axial direction. Preferably, the paper-cut structure 12 is sealed inside the silicone skin by casting, and the restriction layer 13 is adhered to the bottom of the silicone skin by a silicone adhesive after pre-stretching. The silicone layer 11 of the artificial muscle tendril 1 is made of Ecoflex00-20 and Dragon skin10, and the material of the paper-cut structure 12 is PET, and a copper film is electroplated on the surface of the paper-cut structure 12, so that the artificial muscle imitating plant tendril can simulate artificial muscles more realistically. When the artificial muscle tendril 1 is evacuated and contracted, the artificial muscle tendril 1 body is extended spirally from the middle to both sides in the axial direction under the action of the restriction layer 13. The left side is a left-handed part (section A in the figure) and the right side is a right-handed part (section B in the figure), and the recurved section is between the left-handed part and the right-handed part. When the artificial muscle is inflated, the recurved section rotates around the central axis to produce contraction. By imitating the appearance structure of plants and animals, a flexible circuit is etched onto the paper-cut structure 12, so that the artificial muscle imitating the plant tendril has both movement and perception capabilities.

[0034] like Figure 3As shown, a human-like arm includes an upper arm unit 2, a lower arm unit 3 and the artificial muscle imitating plant tendril, the upper arm unit 2 and the lower arm unit 3 are connected by clearance fit, and the two sides of the artificial muscle tendril 1 body are fixedly connected to the upper arm unit 2 and the lower arm unit 3 respectively. The upper arm unit 2 and the lower arm unit 3 are made of acrylic, so that the upper arm unit 2 and the lower arm unit 3 can simulate the artificial arm more realistically. The upper arm unit 2 includes a shoulder joint 21, an upper arm 22, a fixed upper arm rod 23 and a movable upper arm rod 24, an upper arm positioning hole 221 is opened on the upper arm 22, the shoulder joint 21 is connected to one end of the upper arm 22 by clearance fit, the fixed upper arm rod 23 is tightly connected to the upper arm 22 by interference fit, the movable upper arm rod 24 is connected to the upper arm positioning hole 221 on the upper arm 22 by clearance fit, and one side of the artificial muscle tendril 1 is fixedly mounted on the movable upper arm rod 24. The forearm unit 3 includes an elbow joint 31, a forearm 32, a fixed forearm rod 33, a movable forearm rod 34 and a weight-bearing member 35. The forearm 32 is provided with a forearm positioning hole 321. The elbow joint 31 is connected to one end of the forearm 32 and the other end of the upper arm 22 through clearance fit, respectively. The weight-bearing member 35 is fixedly connected to the other end of the forearm 32. The fixed forearm rod 33 is tightly connected to the forearm 32 through interference fit. The movable forearm rod 34 is connected to the forearm positioning hole 321 on the forearm 32 through clearance fit. The other side of the artificial muscle tendril 1 is fixedly mounted on the movable forearm rod 34. The length of the upper arm 22 is preferably greater than the length of the forearm 32, so as to facilitate more realistic simulation of the artificial arm. The number of the upper arm positioning holes 221 is several, and the several upper arm positioning holes 221 are arranged at equal intervals along the same straight line on the upper arm 22, so that the movable upper arm rod 24 can be detachably fixedly connected in the upper arm positioning hole 221 at the desired position, so as to facilitate measurement. The number of the forearm positioning holes 321 is several, and the several forearm positioning holes 321 are arranged at equal intervals along the same straight line on the forearm 32. It is used to make the movable forearm rod 34 detachably fixedly connected in the forearm positioning hole 321 at the desired position, which is convenient for measurement. A U-shaped groove is provided on the forearm 32 at the end side of the weight-bearing piece 35, and the weight-bearing piece 35 and the forearm 32 are detachably fixedly connected through the U-shaped groove, which is convenient for the installation and replacement of the weight-bearing piece 35. The weight-bearing piece 35 can be a dumbbell, a weight, etc. When the artificial muscle tendril 1 contracts, the forearm unit 3 is driven to rotate and lift the weight-bearing piece 35. The changes in the number of spiral turns and the pitch cause the inductance to change, and different bending angles correspond to different electrical signals. As the number of spiral turns and the pitch change when the artificial muscle tendril 1 is extended or shortened, the inductance changes, and the inductance changes with the change in the bending degree. It provides a new way to achieve high-precision closed-loop feedback control, precise identification and human-computer interaction of soft robots.

[0035] Specifically, the overall length of the upper arm 22 is 310 mm, and the upper arm 22 includes 22 upper arm positioning holes 221, each hole is linearly arranged and arranged at equal intervals along the same straight line, and the aperture is 5 mm. The upper arm 22 is divided into two groups, and the two groups of upper arms 22 are symmetrically distributed. The fixed upper arm rod 23 is installed between the two groups of upper arms 22, and the movable upper arm rod 24 is installed between a group of upper arm positioning holes 221 corresponding to the two groups of upper arms 22. The overall length of the forearm 32 is 292 mm, and the forearm 32 includes 18 forearm positioning holes 321, each hole is linearly arranged and arranged at equal intervals along the same straight line, and the aperture is 5 mm. The forearm 32 is divided into two groups, and the two groups of lower arms 32 are symmetrically distributed. The fixed lower arm rod 33 is installed between the two groups of lower arms 32, and the movable lower arm rod 34 is installed between a group of upper and lower arm positioning holes 321 corresponding to the two groups of lower arms 32. This allows the human-like arm to simulate an artificial arm more realistically.

[0036] like Figure 4 As shown, a testing method for simulating a human arm comprises the following steps:

[0037] S1: Use electrostatic collection equipment to record the electrical signals generated by artificial muscles with embedded sensing capabilities, and the LCR meter transmits the signals to the computer and is displayed and recorded by BenchVue;

[0038] S2: Using a professional camera to record the bending angle of the forearm 32;

[0039] S3: Based on the electrical signal output by S1 and the angle recorded by S2, the lifting angle of the forearm 32 is characterized by inductance.

[0040] like Figure 5 , which is a relationship diagram between the rotation angle of the arm unit 3 and the inductance signal of the human arm simulation device according to the present invention. The test results show that the inductance signal increases with the increase of the rotation angle of the arm unit 3.

[0041] like Figure 6 As shown in the figure, the results of the durability test of the artificial muscle imitating plant tendril described in the present invention are shown. ΔX is the lifting displacement of the artificial muscle tendril 1 after 1000 consecutive liftings, and ΔL is the sensor signal value of the artificial muscle tendril 1 after 1000 consecutive liftings. The experimental results show that after 1000 consecutive liftings, the lifting displacement is between 31-34mm, and the sensor signal value is between 23-26nH, with no obvious changes. The artificial muscle tendril 1 has good stability and durability. Therefore, it has an ultra-long service life and extremely high stability, can realize the detection of the human body arm picking up and placing objects, and has the advantages of self-driven sensing, high measurement accuracy and long service life.

[0042] Working principle:

[0043] The artificial muscle roll is made by imitating plant tendrils with the help of the programmable characteristics of flexible circuit etching and embedded paper-cut structure 12. When the artificial muscle tendril 1 contracts, it drives the small arm unit 3 to rotate and lift the load-bearing member 35. The change in the number of spiral turns and pitch causes the change in inductance, and different bending angles correspond to different electrical signals. It has the characteristics of miniaturization and integration, and can realize real-time monitoring of the human-like arm taking and placing objects while maintaining the integrity and functional integrity of the artificial muscle, providing a theoretical and experimental basis for the development of new self-driven and self-sensing artificial muscles.

[0044] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. An artificial muscle imitating plant tendrils, characterized in that: The invention comprises an artificial muscle tendril (1) body, wherein the artificial muscle tendril (1) body comprises a silicone skin, a paper-cut structure (12) and a restriction layer (13), wherein the paper-cut structure (12) is sealed and installed inside the silicone skin, a flexible circuit is etched on the paper-cut structure (12), and the restriction layer (13) is fixedly installed at the bottom of the silicone skin after being pre-stretched, and is used to extend the artificial muscle tendril (1) body in a spiral shape from the middle to both sides in the axial direction. When the artificial muscle tendril (1) is deflated and contracted, the artificial muscle tendril (1) body is extended in a spiral shape from the middle to both sides in the axial direction under the action of the restriction layer (13), wherein the left side is a left-handed part and the right side is a right-handed part, and a recurved section is between the left-handed part and the right-handed part. When the artificial muscle is inflated, the recurved section rotates around the central axis to generate contraction.

2. The artificial muscle imitating plant tendril according to claim 1, characterized in that: The material of the silicone layer (11) of the artificial muscle tendril (1) is Ecoflex00-20 and Dragon skin10, the material of the paper-cut structure (12) is PET, and a copper film is electroplated on the surface of the paper-cut structure (12).

3. A humanoid arm, characterized in that: The upper arm unit (2), the lower arm unit (3) and the artificial muscle imitating the plant tendril according to any one of claims 1 or 2, wherein the upper arm unit (2) and the lower arm unit (3) are connected by gap fit, and the two sides of the artificial muscle tendril (1) body are respectively fixedly connected to the upper arm unit (2) and the lower arm unit (3).

4. The humanoid arm according to claim 3, characterized in that: The upper arm unit (2) comprises a shoulder joint (21), an upper arm (22), a fixed upper arm rod (23) and a movable upper arm rod (24); an upper arm positioning hole (221) is provided on the upper arm (22); the shoulder joint (21) is connected to one end of the upper arm (22) by clearance fit; the fixed upper arm rod (23) is tightly connected to the upper arm (22) by interference fit; the movable upper arm rod (24) is connected to the upper arm positioning hole (221) on the upper arm (22) by clearance fit; and one side of the artificial muscle tendril (1) is fixedly mounted on the movable upper arm rod (24).

5. The humanoid arm according to claim 4, characterized in that: The number of the upper arm positioning holes (221) is several, and the several upper arm positioning holes (221) are arranged on the upper arm (22) along the same straight line at equal intervals.

6. The humanoid arm according to claim 4, characterized in that: The forearm unit (3) comprises an elbow joint (31), a forearm (32), a fixed forearm rod (33), a movable forearm rod (34) and a weight-bearing piece (35); a forearm positioning hole (321) is provided on the forearm (32); the elbow joint (31) is respectively connected to one end of the forearm (32) and the other end of the upper arm (22) by clearance fit; the weight-bearing piece (35) is fixedly connected to the other end of the forearm (32); the fixed forearm rod (33) is tightly connected to the forearm (32) by interference fit; the movable forearm rod (34) is connected to the forearm positioning hole (321) on the forearm (32) by clearance fit; and the other side of the artificial muscle tendril (1) is fixedly mounted on the movable forearm rod (34).

7. The humanoid arm according to claim 6, characterized in that: The number of the forearm positioning holes (321) is several, and the several forearm positioning holes (321) are arranged at equal intervals along the same straight line on the forearm (32).

8. The humanoid arm according to claim 6, characterized in that: The length of the upper arm (22) is greater than the length of the lower arm (32).

9. The humanoid arm according to claim 6, characterized in that: A U-shaped groove is provided on the small arm (32) at the end side of the weight-bearing member (35), and the weight-bearing member (35) and the small arm (32) are detachably fixedly connected via the U-shaped groove.

10. A testing method for simulating a human arm, characterized in that: The steps include: S1: Collecting the electrical signal generated by any one of the humanoid arms in claims 3 to 9, and transmitting the signal to a computer through a measuring meter for display and recording; S2: using a professional camera to record the bending angle of the forearm (32); S3: Based on the electrical signal output by S1 and the angle recorded by S2, the lifting angle of the forearm (32) is characterized by inductance.

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