An artificial muscle device with multiple contraction modes

Abstract

The application discloses an artificial muscle device with multiple contraction modes, which comprises multiple variable limiters and rigid-flexible coupling rings arranged at intervals and capable of being buckled with each other, the variable limiter is a structure with a function similar to a negative Poisson ratio, is in a closed ring shape, comprises two end plates and two bent rods which are parallel to each other, the bent rods can be further deformed, a transverse pull rope is arranged between the two bent rods, a longitudinal pull rope is arranged between the two rigid-flexible coupling rings in the variable limiter, the transverse pull rope and the longitudinal pull rope are both made of a photosensitive or thermosensitive liquid crystal elastomer, can be moderately contracted under the action of light or a heat source, so that the overall contraction of the artificial muscle is controlled, and the multiple transverse pull ropes and the longitudinal pull rope can be independently controlled, have different contraction amounts, and fine control of the artificial muscle is realized.

Description

Technical Field

[0001] This invention relates to an artificial muscle device with multiple contraction modes and its control method, which can simulate different forms of muscle movement. It is particularly suitable for the development of biomimetic flexible robots, and has important technical support and broad application prospects. Background Technology

[0002] In nature, skeletal movement typically relies on the coordinated action of antagonist and agonist muscles. Taking elbow flexion and extension as an example, the biceps brachii and triceps brachii act as antagonist and agonist muscles, respectively, achieving control through contraction and extension. This precise coordination of paired muscles not only provides the force for movement but also accurately controls the speed and stability of the motion. Muscle movement patterns mainly include concentric contraction, isometric contraction, and eccentric contraction.

[0003] Concentric contraction: a form of movement generated by muscle shortening, and the main mode of force output;

[0004] Isometric contraction: A muscle exerts force while maintaining a constant length to maintain postural or structural stability;

[0005] Eccentric contraction: Muscles gradually lengthen under the action of external force, used to control the deceleration and balance of movement.

[0006] Significant technical challenges remain in the field of artificial muscles, particularly in achieving eccentric contraction. Currently, existing artificial muscle fibers typically achieve contraction by altering the internal structure of the material; however, this structure suffers irreversible damage during eccentric contraction. This damage not only affects the durability of the artificial muscle but also severely limits its precision and stability. Therefore, achieving eccentric contraction without damaging the material structure is crucial for improving the performance of artificial muscles. This is essential for the application of flexible robots and smart wearable devices, as these devices need to maintain efficient and stable performance across various motion modes.

[0007] To address the aforementioned problems, the inventors have conducted in-depth research on methods for achieving non-destructive eccentric contraction, with the aim of designing an artificial muscle device with multiple contraction modes that can solve the above problems. Summary of the Invention

[0008] To overcome the aforementioned problems, the inventors conducted intensive research and designed an artificial muscle device with multiple contraction modes. This artificial muscle includes multiple spaced and interlocking variable limiters and rigid-flexible coupling rings. The variable limiters have a structure similar to a negative Poisson's ratio, are closed rings, and include two parallel end plates and two bent rods. The bent rods can be further deformed, and a transverse pull rope is provided between the two bent rods. In the variable limiters, a longitudinal pull rope is provided between the two rigid-flexible coupling rings. Both the transverse and longitudinal pull ropes are made of photosensitive or heat-sensitive liquid crystal elastomers, which can contract appropriately under the action of light or heat sources, thereby controlling the overall contraction of the artificial muscle. Moreover, the multiple transverse and longitudinal pull ropes can be controlled independently, each with a different amount of contraction, thus achieving precise control of the artificial muscle, thereby completing this invention.

[0009] Specifically, the purpose of this invention is to provide an artificial muscle device with multiple contraction modes. The artificial muscle includes a variable limiter 1, a rigid-flexible coupling ring 2, and a smart material. The variable limiter 1 is used to maintain stability and withstand external forces in different motion modes. The rigid-flexible coupling ring 2 is used to improve the adaptability and buffering performance of the artificial muscle. The smart material is used to provide the main driving force.

[0010] The variable limiter 1 is in the shape of a closed ring, including two end plates 11 arranged parallel to each other, and two bent rods 12 connected between the two end plates 11. The cross-sectional dimensions of the bent rods 12 are smaller than the cross-sectional dimensions of the end plates 11, and the middle part of the bent rods 12 bends toward the inner side of the ring. The bending angle is adjusted according to the force applied to the end plates 11.

[0011] Preferably, the angle of the bend in the bent rod 12 is 150-170 degrees.

[0012] The rigid-flexible coupling ring 2 is elliptical in shape, and the ellipse is formed by connecting two straight line segments and two semicircular arc segments.

[0013] The middle part of the straight segment is a flexible segment 21 made of flexible material, and the other parts of the rigid-flexible coupling ring 2 are rigid segments 22 made of rigid material. The rigid segment 22 provides support and maintains the shape, while the flexible segment 21 allows the artificial muscle to deform to a predetermined size when subjected to external force.

[0014] The variable limiter 1 and the rigid-flexible coupling ring 2 are alternately connected to form a chain-like artificial muscle.

[0015] That is, each variable limiter 1 is connected to both sides of a rigid-flexible coupling ring 2; and each rigid-flexible coupling ring 2 is connected to one or two variable limiters 1.

[0016] In the variable limiter 1, a transverse pull rope 31 made of smart material is provided between the two bent rods 12.

[0017] The transverse pull rope 31 is arranged parallel to the end plate 11;

[0018] The horizontal pull rope 31 is connected to the apex of the bent part of the bent rod 12.

[0019] In the variable limiter 1, a longitudinal pull rope 32 made of smart material is provided between the two rigid-flexible coupling rings 2.

[0020] The longitudinal pull rope 32 is substantially perpendicular to the end plate 11;

[0021] The longitudinal pull rope 32 is connected to the top of the rigid-flexible coupling ring 2.

[0022] The smart material is a liquid crystal elastomer; the liquid crystal elastomer can achieve axial contraction by converting from anisotropic to isotropic under light or heat stimulation.

[0023] Each horizontal pull rope 31 and each vertical pull rope 32 is covered with a protective layer to block light or insulate heat. A light source or heat source is also provided inside the protective layer. The amount of contraction of the horizontal pull rope 31 and the vertical pull rope 32 is adjusted by controlling the light intensity of the light source or the temperature of the heat source.

[0024] Preferably, the light source / heat source in each protective layer is controlled independently, and the light intensity / temperature in each protective layer can be different.

[0025] In the variable limiter 1, a groove 4 is provided on the inner side of the end plate 11, and the rigid-flexible coupling ring 2 is embedded in the groove 4;

[0026] Preferably, one or more rigid-flexible coupling rings 2 are fastened together between two adjacent variable limiters 1;

[0027] When the number of rigid-flexible coupling rings 2 between two adjacent variable limiters 1 is more than two, correspondingly, each end plate 11 is also provided with more than two grooves 4;

[0028] Each end of the rigid-flexible coupling ring 2 is connected to a longitudinal pull rope 32.

[0029] The present invention also provides a control method for an artificial muscle device with multiple contraction modes, the method comprising the following steps:

[0030] Step 1: Alternately connect the variable limiter 1 and the rigid-flexible coupling ring 2 to form a chain-like artificial muscle, and arrange the transverse pull rope 31 and the longitudinal pull rope 32 in the variable limiter 1.

[0031] Step 2: Fix multiple artificial muscles to both sides of the simulated joint or simulated bone;

[0032] Step 3: By controlling the light intensity of the light source or the temperature of the heat source, the contraction amount of each transverse tension rope 31 and each longitudinal tension rope 32 is adjusted, thereby controlling the length of the variable limiter 1 and the rigid-flexible coupling ring 2 to simulate various muscle movement patterns.

[0033] The beneficial effects of this invention include:

[0034] (1) The artificial muscle device with multiple contraction modes provided by the present invention can simulate the three main contraction modes of muscles, so that the artificial muscle can exhibit biomimetic dynamic characteristics under different conditions, that is, it has multimodal biomimetic capability.

[0035] (2) The artificial muscle device with multiple contraction modes provided by the present invention is applicable to bionic systems such as bionic robots and smart wearable devices that require precise control and stable output, and can effectively improve the flexibility and simulation effect of the device.

[0036] (3) The artificial muscle device with multiple contraction modes provided by the present invention is provided with multiple variable limiters, which are structures with a function similar to negative Poisson's ratio, and can maintain stability and withstand external forces in different movement modes.

[0037] (4) According to the artificial muscle device with multiple contraction modes provided by the present invention, multiple rigid-flexible coupling rings are provided thereon. The rigid segment of the rigid-flexible coupling ring can provide basic support and shape retention capability, and the flexible segment allows the artificial muscle to undergo moderate deformation when subjected to external force, thereby improving the adaptability and buffering performance of the structure.

[0038] (5) The artificial muscle device with multiple contraction modes provided by the present invention is provided with a transverse pull rope and a longitudinal pull rope in the variable limiter, which can shorten the distance between each link under light or heat stimulation, thereby realizing the centripetal contraction of the overall structure; in the centripetal contraction and isometric contraction modes, it acts as a driving force to drive the structure to move, ensuring the force output and movement accuracy of the structure. Attached Figure Description

[0039] Figure 1 A schematic diagram of the overall structure of the artificial muscle device with multiple contraction modes in this application is shown;

[0040] Figure 2 A schematic diagram of the variable limiter of the artificial muscle device with multiple contraction modes in this application is shown;

[0041] Figure 3This illustration shows a schematic diagram of the simulated biceps and triceps muscle groups in an embodiment of this application.

[0042] Explanation of reference numerals in the attached figures

[0043] 1-Variable limit switch

[0044] 11-End plate

[0045] 12-Bend Rod

[0046] 2-Rigid-Flexible Coupling Ring

[0047] 21-Flexible segment

[0048] 22-Rigid Section

[0049] 31-Horizontal pull rope

[0050] 32-Longitudinal pull rope

[0051] 4-groove

[0052] 5-Biceps brachii group

[0053] 6-Triceps Brachii Group

[0054] 7-Arm Detailed Implementation

[0055] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.

[0056] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0057] This invention provides an artificial muscle device with multiple contraction modes, such as... Figure 1 As shown, the artificial muscle includes a variable limiter 1, a rigid-flexible coupling ring 2, and a smart material; the variable limiter 1 is used to maintain stability and withstand external forces in different motion modes; the rigid-flexible coupling ring 2 is used to improve the adaptability and buffering performance of the artificial muscle; and the smart material is used to provide the main driving force.

[0058] In a preferred embodiment, the variable limiter 1 is a closed ring with a structure similar to a negative Poisson's ratio. It includes two parallel end plates 11 and two bent rods 12 connected between the two end plates 11. The cross-sectional dimensions of the bent rods 12 are smaller than those of the end plates 11, and the middle of the bent rods 12 bends toward the inner side of the ring. The bending angle is adjusted according to the magnitude of the force applied to the end plates 11.

[0059] Preferably, the angle of the bend in the bent rod 12 is 150-170 degrees, and when there is no bend, the angle of the bend is 180 degrees.

[0060] Preferably, the end plate 11 and the bent rod 12 of the variable limiter 1 are both made of acrylonitrile-butadiene-stafin copolymer (ABS), and the cross-sectional dimensions of the bent rod are 8-12 mm. 2 Preferably 10mm 2 about.

[0061] In a preferred embodiment, such as Figure 2 As shown, the rigid-flexible coupling ring 2 is generally elliptical, and the ellipse is formed by connecting two straight line segments and two semicircular arc segments.

[0062] The middle part of the straight segment is a flexible segment 21 made of flexible material, and the other parts of the rigid-flexible coupling ring 2 are rigid segments 22 made of rigid material. The rigid segment 22 provides support and maintains the shape, while the flexible segment 21 enables the artificial muscle to deform to a predetermined size when subjected to external force, thereby improving the adaptability and buffering performance of the artificial muscle.

[0063] In this application, the flexible segment is made of rubber material, has a length of 4-5 mm, and can provide 50% deformation.

[0064] The rigid section is made of ABS, approximately 8mm in length, and has a cross-sectional dimension of 15mm. 2 .

[0065] In a preferred embodiment, such as Figure 1 As shown, the variable limiter 1 and the rigid-flexible coupling ring 2 are alternately connected to form a chain-like artificial muscle.

[0066] That is, each variable limiter 1 is connected to both sides of a rigid-flexible coupling ring 2; and each rigid-flexible coupling ring 2 is connected to one or two variable limiters 1.

[0067] In this application, when the artificial muscle is not under stress, the variable limiter 1 and the rigid-flexible coupling ring 2 will not be in direct contact and will be kept at a certain distance from each other. When the artificial muscle contracts centripetally, the distance between the variable limiter 1 and the rigid-flexible coupling ring 2 will gradually decrease under the action of the pull rope until they come into contact.

[0068] Preferably, such as Figure 1 and Figure 2 As shown, in the variable limiter 1, a transverse pull rope 31 made of smart material is provided between the two bent rods 12.

[0069] The transverse pull rope 31 is arranged parallel to the end plate 11;

[0070] The horizontal pull rope 31 is connected to the apex of the bent part of the bent rod 12.

[0071] By pulling the bent rod 12 inward with the transverse pull rope 31, the overall length of the variable limiter 1 is shortened, thereby achieving muscle contraction.

[0072] Preferably, such as Figure 1 and Figure 2 As shown, in the variable limiter 1, a longitudinal pull rope 32 made of smart material is provided between the two rigid-flexible coupling rings 2.

[0073] The longitudinal pull rope 32 is substantially perpendicular to the end plate 11;

[0074] The longitudinal pull rope 32 is connected to the top of the rigid-flexible coupling ring 2.

[0075] By stretching the two rigid-flexible coupling rings 2 inward through the longitudinal pull rope 32, the distance between the two rigid-flexible coupling rings 2 is shortened, thereby achieving muscle contraction.

[0076] In this application, under the combined action of the transverse tension rope 31 and the longitudinal tension rope 32, the distance between the variable limiter 1 and the two rigid-flexible coupling rings 2 decreases synchronously, thereby enabling the overall artificial muscle to contract. In the concentric contraction and isometric contraction modes, the transverse tension rope 31 and the longitudinal tension rope 32 act as driving forces to drive the artificial muscle to move, ensuring the force output and movement accuracy of the artificial muscle.

[0077] In this application, when the transverse pull rope 31 and the longitudinal pull rope 32 are controlled to retract, the overall length of the variable limiter 1 gradually shortens. After the rigid-flexible coupling ring 2 is embedded in the groove 4, the variable limiter 1 and the rigid-flexible coupling ring 2 gradually come into contact.

[0078] In a preferred embodiment, the smart material is a liquid crystal elastomer (LCE); the liquid crystal elastomer can achieve axial contraction by converting from anisotropic to isotropic under light or heat stimulation.

[0079] In a preferred embodiment, each transverse pull rope 31 and each longitudinal pull rope 32 is covered with a protective layer to block light or insulate heat; a light source or heat source is also provided inside the protective layer, and the amount of contraction of the transverse pull rope 31 and the longitudinal pull rope 32 is adjusted by controlling the light intensity of the light source or the temperature of the heat source.

[0080] Preferably, the light sources / heat sources in each protective layer are controlled independently, and the light intensity / temperature in each protective layer can be different. Each light source / heat source is connected to a control system, which sets the contraction amount for each rope according to the contractile force and contraction amount required by the artificial muscle, and thus sets an appropriate light intensity / temperature.

[0081] In a preferred embodiment, a groove 4 is provided on the inner side of the end plate 11 on the variable limiter 1, and the rigid-flexible coupling ring 2 can be embedded into the groove 4;

[0082] Preferably, such as Figure 2 As shown, one or more rigid-flexible coupling rings 2 are connected between two adjacent variable limiters 1;

[0083] When the number of rigid-flexible coupling rings 2 between two adjacent variable limiters 1 is more than two, correspondingly, each end plate 11 is also provided with more than two grooves 4;

[0084] Each end of the rigid-flexible coupling ring 2 is connected to a longitudinal pull rope 32.

[0085] In this application, by setting multiple parallel rigid-flexible coupling rings and longitudinal tension ropes 32 connected to them, the output force can be enhanced, so that the artificial muscle remains stable and reliable under high load.

[0086] The present invention also provides a control method for an artificial muscle device with multiple contraction modes, the method comprising the following steps:

[0087] Step 1: Alternately connect the variable limiter 1 and the rigid-flexible coupling ring 2 to form a chain-like artificial muscle, and arrange a transverse pull rope 31 and a longitudinal pull rope 32 in the variable limiter 1; the transverse pull rope 31 is connected to the apex of the bending part of the two bent rods 12 of the variable limiter; the longitudinal pull rope 32 is connected to the top of the two adjacent rigid-flexible coupling rings 2.

[0088] Step 2: Fix multiple artificial muscles on both sides of the simulated joint or simulated bone; so that the multiple artificial muscles are all in a state of isometric contraction, so that the simulated joint or simulated bone is in a straightened state;

[0089] Step 3: By controlling the light intensity of the light source or the temperature of the heat source, the contraction amount of each transverse tension rope 31 and each longitudinal tension rope 32 is adjusted, thereby controlling the length of the variable limiter 1 and the rigid-flexible coupling ring 2 to simulate various muscle movement patterns; the various movement patterns include concentric contraction, isometric contraction and eccentric contraction.

[0090] Example

[0091] Choose such Figure 1 and Figure 2 The artificial muscle device shown, which has multiple contraction modes, simulates the biceps and triceps brachii muscle groups, and specifically includes the following steps:

[0092] Step 1: Alternately fasten and connect the variable limiter 1 and the rigid-flexible coupling ring 2 to form a chain-like artificial muscle, and arrange the transverse pull rope 31 and the longitudinal pull rope 32 in the variable limiter 1.

[0093] Step 2: Assemble two artificial muscles to simulate the biceps brachii group 5 and the triceps brachii group 6 respectively. Connect the biceps brachii group 5 and the triceps brachii group 6 to both sides of the simulated elbow joint. In the initial state, the biceps brachii and triceps brachii are in isometric contraction state to keep the arm 7 straight.

[0094] Step 3, simulate arm flexion: such as Figure 3 As shown in Figure B, at the onset of arm flexion, light stimulation is applied to the smart material in the biceps brachii group, causing it to contract concentrically, generating contractile force and driving the arm to bend. Simultaneously, to control the speed and stability of arm flexion, the light stimulation of the smart material in the triceps brachii group is controlled to apply a gradually stretching external force, causing it to enter an eccentric contraction mode. At this time, the variable limiter of the triceps brachii group bears part of the external force through a negative Poisson's ratio structure. That is, when the variable limiter comes into contact with the rigid-flexible coupling ring, part of the force can be directly transmitted between the variable limiter and the rigid-flexible coupling ring, reducing the stress burden on the smart material and preventing damage to the artificial muscle due to external force, while achieving smooth braking. By adjusting the concentric contraction force of the biceps brachii group and the eccentric contraction resistance of the triceps brachii group, the flexion angle and speed of the arm are precisely controlled.

[0095] Simulate arm extension: such as Figure 3 As shown in Figure C, during arm extension, light stimulation is applied to the smart material in the triceps brachii group to induce concentric contraction, thereby extending the arm. At the same time, the light stimulation of the smart material in the biceps brachii group is controlled to apply a gradually stretching external force, causing it to enter an eccentric contraction mode, thus avoiding arm instability caused by rapid extension. Simultaneously, the variable limiter absorbs external force, disperses stress, and protects the smart material under the support of the negative Poisson's ratio structure. By precisely controlling the concentric contraction of the triceps brachii group and the eccentric resistance of the biceps brachii group, the arm remains stable during extension, avoiding movement imbalance caused by sudden pulling force.

[0096] Simulated arm length mode: such as Figure 3 As shown in A, when the arm is held at a specific angle, the intensity of light applied by the smart material to the biceps and triceps is precisely controlled to control the contraction force of the biceps and triceps, so that they are both in isometric contraction mode. At this time, the two muscle groups maintain the same length, so they work together to stabilize the arm posture. That is, the two sides are the same length, which is isometric mode, but with enough force to resist external disturbances.

[0097] This artificial muscle with multiple contraction modes can achieve coordinated movements similar to the biceps and triceps in a bionic arm, precisely controlling the flexion and extension of the arm and simulating the flexibility and precise control of biological joints. This configuration not only effectively improves the motion stability of flexible bionic robots, but also ensures the durability of artificial muscles under external forces through eccentric contraction mode, meeting the requirements of bionic robots or smart wearable devices for flexibility and mechanical stability.

[0098] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. An artificial muscle device with multiple contraction modes, characterized in that, The artificial muscle includes a variable limiter (1), a rigid-flexible coupling ring (2), and smart materials; the variable limiter (1) is used to maintain stability and withstand external forces in different motion modes; the rigid-flexible coupling ring (2) is used to improve the adaptability and buffering performance of the artificial muscle; the smart materials are used to provide the main driving force. The variable limiter (1) is a closed ring in shape, including two parallel end plates (11) and two bent rods (12) connected between the two end plates (11). The cross-sectional dimensions of the bent rods (12) are smaller than those of the end plates (11), and the middle part of the bent rods (12) bends toward the inner side of the ring. The bending angle is adjusted according to the force at the end plates (11). The angle of the bend at the top of the bent rod (12) is 150-170 degrees; The rigid-flexible coupling ring (2) is elliptical in shape, and the ellipse is formed by connecting two straight line segments and two semicircular arc segments. The middle part of the straight segment is a flexible segment (21) made of flexible material, and the other parts of the rigid-flexible coupling ring (2) are rigid segments (22) made of rigid material; the rigid segment (22) provides support and maintains the shape, and the flexible segment (21) enables the artificial muscle to deform to a predetermined size when subjected to external force; The variable limiter (1) and the rigid-flexible coupling ring (2) are alternately connected to form a chain-like artificial muscle. That is, each variable limiter (1) is connected to a rigid-flexible coupling ring (2) on both sides; each rigid-flexible coupling ring (2) is connected to one or two variable limiters (1); In the variable limiter (1), a transverse pull rope (31) made of smart material is provided between the two bent rods (12). The transverse pull rope (31) is arranged parallel to the end plate (11); The transverse pull rope (31) is connected to the apex of the bent part of the bent rod (12); In the variable limiter (1), a longitudinal pull rope (32) made of smart material is provided between two rigid-flexible coupling rings (2). The longitudinal pull rope (32) is substantially perpendicular to the end plate (11). The longitudinal pull rope (32) is connected to the top of the rigid-flexible coupling ring (2); The smart material is a liquid crystal elastomer; the liquid crystal elastomer can achieve axial contraction by converting from anisotropic to isotropic under light or heat stimulation.

2. The artificial muscle device with multiple contraction modes according to claim 1, characterized in that, Each horizontal pull rope (31) and each vertical pull rope (32) is covered with a protective layer to block light or insulate heat; a light source or heat source is also provided inside the protective layer, and the amount of contraction of the horizontal pull rope (31) and the vertical pull rope (32) is adjusted by controlling the light intensity of the light source or the temperature of the heat source. The light source / heat source in each of the protective layers is controlled independently, and the light intensity / temperature in each protective layer can be different.

3. The artificial muscle device with multiple contraction modes according to claim 1, characterized in that, On the variable limiter (1), a groove (4) is provided on the inner side of the end plate (11), and the rigid-flexible coupling ring (2) can be embedded in the groove (4) when it contracts.

4. The artificial muscle device with multiple contraction modes according to claim 1, characterized in that, One or more rigid-flexible coupling rings (2) are fastened together between two adjacent variable limiters (1); When the number of rigid-flexible coupling rings (2) between two adjacent variable limiters (1) is more than two, correspondingly, each end plate (11) is also provided with more than two grooves (4). Each rigid-flexible coupling ring (2) has a longitudinal pull rope (32) connected to its end.

5. A control method for an artificial muscle device with multiple contraction modes as described in any one of claims 1 to 4, characterized in that, The method includes the following steps: Step 1: Alternately connect the variable limiter (1) and the rigid-flexible coupling ring (2) to form a chain-like artificial muscle, and arrange the transverse pull rope (31) and the longitudinal pull rope (32) in the variable limiter (1). Step 2: Fix multiple artificial muscles to both sides of the simulated joint or simulated bone; Step 3: By controlling the light intensity of the light source or the temperature of the heat source, the contraction amount of each transverse rope (31) and each longitudinal rope (32) is adjusted, thereby controlling the length of the variable limiter (1) and the rigid-flexible coupling ring (2) to simulate various muscle movement patterns.

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