Fiber-like dielectric elastomer actuator and dexterous hand applications

Abstract

Fibrous dielectric elastomer driver and dexterous hand application belong to the field of flexible material application. In the application, the spring and the two fibers form an antagonistic structure through the intermediate plate, and the fibers are fixed on the right side of the bottom plate through the fixing piece after being pre-stretched. The tension of the fiber decreases under the action of Maxwell stress after being electrified, and the spring tension is greater than the fiber, so as to contract, and the spring contraction pulls the string to realize the active external force output, and further drive the rope-driven dexterous hand to act. The structure can change the force output mode of the dielectric elastomer fiber, and realize the active output of electrification. In order to further improve the output displacement, a layer of driving unit is added on the basis of the single-layer driving unit to form a double-layer series structure, two sections of fibers are connected through a string and are changed in direction through a pulley, and the pulley has no motion interference with the lower driving unit. After electrification, the spring drives the lower fiber to move, and the left end of the upper fiber is fixed, and the right side moves to the right under the traction of the string, so as to add the displacement of the two sections of fibers, and realize greater displacement.

Description

Technical Field

[0001] This invention relates to fibrous dielectric elastomer actuators and dexterous hand applications, belonging to the field of flexible material applications. Background Technology

[0002] With the rapid development of artificial intelligence and robotics, humanoid robots are moving from the laboratory to real-world applications, showing great promise. As the core actuator of humanoid robots, the dexterous hand currently relies on a motor and reducer drive system, which suffers from drawbacks such as heavy weight, difficulty in integrating multiple degrees of freedom, stiff movements, and high operating noise. Designing a high-performance bionic dexterous hand driven by artificial muscles, based on the morphology and working mechanism of biological muscles, to replace the traditional motor-driven solution is of great significance for advancing humanoid robot technology.

[0003] Commonly used flexible actuators include shape memory alloys, pneumatic actuators, and dielectric elastomer actuators. Dielectric elastomers (DEs) are typical electroactive polymer artificial muscles that can produce controllable deformation under an applied electric field, possessing advantages such as high energy density, fast response, light weight, and excellent flexibility. When flexible electrodes are uniformly covered on both sides of a dielectric elastomer film and a voltage is applied, the opposite charges on the upper and lower sides attract each other, allowing the film to produce significant shape changes.

[0004] Traditional fibrous dielectric elastomers operate in a passive output mode, requiring an antagonistic structure with an elastic element and relying on a rigid frame to fix the pre-stretched fibers. Addressing these issues, this invention utilizes a fibrous dielectric elastomer as its core to develop a novel driving scheme adapted for dexterous hands, enabling stable bending movements and providing a certain load-bearing capacity. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a fibrous dielectric elastomer actuator and a dexterous hand application. This invention selects carbon nanotubes (CNTs) as flexible and stretchable electrodes, stacks two identical thin films covering the electrodes, and forms fibers by winding them. The fibers are then pre-stretched, which significantly improves axial output displacement while constraining radial deformation.

[0006] The technical solution adopted in this invention is: a fibrous dielectric elastomer actuator, which includes an actuator base, an intermediate plate, a tension spring, and dielectric elastomer fibers;

[0007] One end of the driver base is a tension spring end, and the other end is a fiber end;

[0008] One end of the tension spring is connected to the tension spring end via a first high-molecular-weight polyethylene (HMWPE) thin rope, and the other end of the tension spring is connected to the intermediate plate via a second HMWPE thin rope. One end of the second HMWPE thin rope is connected to the end of the tension spring furthest from the tension spring end, and the other end passes through the through hole of the intermediate plate and is knotted in the middle for fixation. The end that extends out of the limiting end is the free end of the rope, which is used for external output.

[0009] One end of the dielectric elastomer fiber is connected to the intermediate plate, and the other end is fixed to the fastener;

[0010] The force of the tension spring and the force of the dielectric elastomer fiber antagonize each other at the intermediate plate.

[0011] Furthermore, the dielectric elastomer fiber includes two sets: a first dielectric elastomer fiber and a second dielectric elastomer fiber. One end of each fiber passes through the fiber through-hole of the intermediate body and is fixed thereafter, while the other end is fixed to a fixing member, which is fixedly disposed at the fiber end.

[0012] Furthermore, consider the tensile force of a single dielectric elastomer fiber in its steady state when no power is applied. Spring tension Tension on the thin polyethylene rope When dielectric elastomer fibers antagonize springs:

[0013] + =

[0014] Assume that the tensile force of a single dielectric elastomer fiber decreases after energization. Fiber stiffness coefficient Spring stiffness coefficient The displacement is x, and we have

[0015]

[0016] The calculation yielded:

[0017]

[0018] This refers to obtaining the distance that the dielectric elastomer fiber can be pulled before and after being energized.

[0019] Furthermore, the fibrous dielectric elastomer actuator comprises four groups of dielectric elastomer fibers: a first dielectric elastomer fiber, a second dielectric elastomer fiber, a third dielectric elastomer fiber, and a fourth dielectric elastomer fiber. One end of the first and second dielectric elastomer fibers passes through the fiber through-hole of the intermediate body and is fixed, while the other end is fixed to one side of the fixing member, which can move with tension. On the other side of the fixing member, a pulley rope passes around the first pulley and connects to the intermediate connecting block. One end of the fourth dielectric elastomer fiber is connected to the fiber fixing block, and the other end is connected to the intermediate connecting block. The fiber fixing block is located at the tension spring end.

[0020] Furthermore, the first and second dielectric elastomer fibers are on the same horizontal plane, and the third and fourth dielectric elastomer fibers are on the same plane, forming an upper and lower two-layer structure through the first pulley.

[0021] Furthermore, the first dielectric elastomer fiber, the second dielectric elastomer fiber, the third dielectric elastomer fiber, and the fourth dielectric elastomer fiber together antagonize the tension spring at the intermediate plate.

[0022] Furthermore, the first dielectric elastomer fiber, the second dielectric elastomer fiber, and the third dielectric elastomer fiber together antagonize the tension spring at the intermediate plate.

[0023] A dexterous hand using the aforementioned fibrous dielectric elastomer actuator includes an arm, a palm, and fingers, wherein the fingers are provided with three joints, which are, in order from the palm toward the fingertip, the metacarpophalangeal joint, the proximal joint, and the distal joint.

[0024] The arm is equipped with an integrated base plate and multiple sets of dielectric elastomer actuator units. The multiple sets of dielectric elastomer actuator units are fixedly installed on the integrated base plate. Each set of dielectric elastomer actuator units includes the fibrous dielectric elastomer actuator, a second pulley, and a tendon rope.

[0025] In each set of dielectric elastomer drive units, one end of the tendon cord is fixedly connected to the end of the tension spring away from the tension spring end, and the other end of the tendon cord passes through the tension spring and the through hole at the tension spring end in sequence and then passes around the second pulley. The other end of the tendon cord is connected to or integrally formed with the free end of the second high molecular weight polyethylene cord. The free end of the cord and the tendon cord constitute a pulling assembly.

[0026] The dexterous hand is configured with 14 degrees of freedom, with three degrees of freedom for each of the four fingers and two degrees of freedom for the thumb. The distal joints of the four fingers are passive degrees of freedom and are linked with the proximal joints, while the remaining degrees of freedom are active degrees of freedom.

[0027] The integrated base plate has a fixing base on the left side for fixing the fibrous dielectric elastomer actuator, and a second pulley on the right side of the integrated base plate. The integrated base plate has through holes on both sides corresponding to each driving unit for fixing. The second pulley is used to connect and cooperate the two ends of the tendon rope that drives the same degree of freedom.

[0028] Each finger is equipped with two sets of pulling components. One set of the pulling components is installed at the proximal and distal joints of the finger, and the other set of the pulling components is installed at the metacarpophalangeal joints of the finger. The tendon cord and the free end of the thin rope of the pulling component pass through the wrist of the palm, and the tendon cord is arranged on the back of the hand.

[0029] The pulling component is wound around the joint of the corresponding finger and fixedly connected to the joint. The bending and repositioning of the finger joint is achieved by pulling the tendon rope and the free end of the thin rope. In the power-on state, the finger is bent by applying a pulling force to the free end of the thin rope on the palm side. The tendon rope on the back side of the hand passes around the fixed pulley and is linked with the spring movable end of the dielectric elastomer actuator unit to achieve synchronous movement of the tendon rope and the free end of the thin rope on both sides of the finger. In the power-off state, the tension spring returns to its original length and drives the tendon rope on the back side of the hand to move, thereby straightening and repositioning the finger.

[0030] Furthermore, each of the dielectric elastomer actuator units corresponds to one degree of freedom of the dexterous hand, and each dielectric elastomer actuator unit operates independently without interfering with each other.

[0031] Furthermore, when the free end of the second high-molecular-weight polyethylene cord is pulled to the left, it causes the corresponding finger joint to bend, while the tendon cord is passively pulled to the right; when the tendon cord is pulled to the left, it causes the corresponding finger to return to its original position and straighten.

[0032] Furthermore, the distal joints of the four fingers achieve passive movement through linkage with the proximal joints, without independent drive components. Each joint of the metacarpophalangeal joint, proximal joint, and thumb is equipped with an independent dielectric elastomer actuator unit to achieve active drive.

[0033] Furthermore, the tension spring and the tendon cord are nested together, and the through hole at the end of the tension spring serves to limit and guide the tendon cord, ensuring the stability of the tendon cord during extension, contraction, and pulling.

[0034] Furthermore, the integrated base plate uses through holes on both sides to position and fix multiple sets of dielectric elastomer actuator units, and works with the right-side fixed pulley to realize tendon rope steering and reversing transmission, adapting to the multi-degree-of-freedom drive layout requirements of dexterous hands.

[0035] The dexterous hand of the fibrous dielectric elastomer actuator described above is used. The actuator unit is fixed on the base plate. The left side of the base plate is the original actuator unit's fixing base, which is used to fix one side of the fiber. Through holes are designed on both sides of each actuator unit for fixing. The right side of the base plate is a fixed pulley, which is used to connect the two ends of the tendon rope that drives each degree of freedom.

[0036] The fingers are driven by tendon cords, each tendon cord wraps around the finger joint and is fixed to the joint. Bending and repositioning can be achieved by stretching the two ends of the cord. When power is applied, the tendon cord on the palm side is pulled to achieve finger bending, while the tendon cord on the other side wraps around the pulley and connects to the spring movable end of the driver unit, so that the tendon cords on both sides of the finger move simultaneously. After power is cut off, the spring returns to its original length, driving the tendon cord on the back of the hand to move, thereby restoring the finger to a straight state.

[0037] The beneficial effects of this invention are as follows: In this invention, the spring and two fibers form an antagonistic structure through an intermediate plate. After the fibers are pre-stretched, they are fixed to the right side of the base plate by a fastener. When the fibers are energized, their tension decreases under Maxwell stress, and the spring tension exceeds that of the fibers, causing them to contract. The spring contraction pulls the thin rope, thereby achieving active external force output and driving the rope-driven dexterous hand movement. This structure can change the force output mode of dielectric elastomer fibers, realizing active force output when energized.

[0038] To further enhance the output displacement, an additional drive unit is added to the single-layer drive unit, forming a double-layer series structure. The two fiber segments are connected by a thin rope and reversed by a pulley, with no motion interference between the pulley and the lower drive unit. When energized, the spring drives the lower fiber to move to the left, while the left end of the upper fiber is fixed, and the right side moves to the right under the traction of the thin rope, thus adding the displacements of the two fiber segments to achieve a larger displacement. Attached Figure Description

[0039] Figure 1 This is a top view of a dielectric elastomer actuator.

[0040] Figure 2 This is a side view of a double-layer dielectric elastomer actuator.

[0041] Figure 3 This is an assembly diagram of a dielectric elastomer actuator.

[0042] Figure 4 This is an assembly diagram of a double-layer dielectric elastomer actuator.

[0043] Figure 5 This is the front view of the middle plate.

[0044] Figure 6 This is a schematic diagram of a stacked structure.

[0045] Figure 7These are schematic diagrams of fiber structure: (a) internal structure of the fiber; (b) schematic diagram of the fiber; (c) actual image of the fiber.

[0046] Figure 8 (a) Output when the output end is fixed (b) Displacement when the output end is unloaded.

[0047] Figure 9 (a) Schematic diagram of forearm integration (b) Schematic diagram of dexterous hand prototype integration.

[0048] Figure 10 It is a multi-driver integrated device

[0049] Figure 11 This is a detailed structural diagram of the right side of the integrated device.

[0050] Figure 12 It is a diagram of the internal wiring of a single finger.

[0051] In the diagram: 1. Driver base; 1a. Spring end; 1b. Fiber end; 2. First high-molecular-weight polyethylene cord; 3. Spring; 4. Intermediate plate; 4a. Cord through hole; 4b. Fiber through hole; 5. Second high-molecular-weight polyethylene cord; 6. First dielectric elastomer fiber; 7. Second dielectric elastomer fiber; 8. Fixing element; 9. Third dielectric elastomer fiber; 10. Fourth dielectric elastomer fiber; 11. Intermediate connecting block; 12. Pulley cord; 13. First pulley; 14. Fiber fixing block; 15. Integrated base plate; 16. First dielectric elastomer drive unit; 17. Second dielectric elastomer drive unit; 18. Third dielectric elastomer drive unit; 19. Tendon cord; 20. Second pulley; 21. Tendon cord fixing point. Detailed Implementation

[0052] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention, but are not limited thereto, unless otherwise stated.

[0053] The specific embodiments of the present invention are described in detail below with reference to the technical solution:

[0054] To address the issues of poor compliance in existing rigid drives for dexterous hands, this invention addresses the following:

[0055] Example 1

[0056] Dielectric elastomers are fabricated into fibers to act as actuators for dexterous hands. For example... Figure 1The drive unit shown consists of a base, a high-molecular-weight polyethylene cord, a tension spring, an intermediate plate, two fibrous dielectric elastomers, and a fixing component. The spring and the two fibers form an antagonistic structure via the intermediate plate. After pre-stretching, the fibers are fixed to the right side of the base plate by the fixing component. When energized, the fibers experience reduced tension under Maxwell stress, causing the spring to contract and pull the cord, thus actively providing output force to drive the rope-driven dexterous hand. This structure can change the force output mode of the dielectric elastomer fibers, enabling active force output upon energization.

[0057] Figure 1 , Figure 2 Hehe Figure 5 A fibrous dielectric elastomer actuator is shown, which includes an actuator base 1, an intermediate plate 4, a tension spring 3, and dielectric elastomer fibers;

[0058] One end of the driver base 1 is a tension spring end 1a, and the other end is a fiber end 1b;

[0059] One end of the tension spring 3 is connected to the tension spring end 1a via a first high molecular weight polyethylene rope 2, and the other end of the tension spring 3 is connected to the intermediate plate 4 via a second high molecular weight polyethylene rope 5.

[0060] Furthermore, one end of the second high-molecular-weight polyethylene cord 5 is connected to the end of the tension spring 3 away from the tension spring end 1a, and the other end passes through the through hole of the intermediate plate 4 and is knotted in the middle. The end that extends and passes through the limiting end 1b is the free end 5a of the cord, which is used for external output.

[0061] One end of the dielectric elastomer fiber is connected to the intermediate plate 4, and the other end is fixed to the fastener 8;

[0062] The force of the tension spring 3 and the force of the dielectric elastomer fiber antagonize each other at the intermediate plate 4.

[0063] The dielectric elastomer fiber includes two sets: a first dielectric elastomer fiber 6 and a second dielectric elastomer fiber 7. One end of each fiber passes through the fiber through hole 4b of the intermediate body 4 and is fixed thereafter, while the other end is fixed to the fixing member 8, which is fixedly located at the fiber end 1b.

[0064] Example 2

[0065] To further increase the output displacement, an additional drive unit can be added to the single-layer drive unit to form a double-layer series structure. The two fiber segments are connected by a thin rope and reversed via a pulley, with no motion interference between the pulley and the lower drive unit. Figure 2 As shown, after being energized, the spring drives the lower fiber to move to the left, while the left end of the upper fiber is fixed and the right side moves to the right under the traction of the thin rope, thus adding the displacements of the two fiber segments to achieve a larger displacement.

[0066] Figure 3, Figure 4 and Figure 5 A fibrous dielectric elastomer actuator is shown, which includes an actuator base 1, an intermediate plate 4, a tension spring 3, and dielectric elastomer fibers;

[0067] One end of the driver base 1 is a tension spring end 1a, and the other end is a fiber end 1b;

[0068] One end of the tension spring 3 is connected to the tension spring end 1a via a first high molecular weight polyethylene rope 2, and the other end of the tension spring 3 is connected to the intermediate plate 4 via a second high molecular weight polyethylene rope 5.

[0069] One end of the dielectric elastomer fiber is connected to the intermediate plate 4, and the other end is fixed to the fastener 8;

[0070] The force of the tension spring 3 and the force of the dielectric elastomer fiber antagonize each other at the intermediate plate 4.

[0071] The fibrous dielectric elastomer actuator comprises four groups of dielectric elastomer fibers: a first dielectric elastomer fiber 6, a second dielectric elastomer fiber 7, a third dielectric elastomer fiber 9, and a fourth dielectric elastomer fiber 10. One end of the first dielectric elastomer fiber 6 and the second dielectric elastomer fiber 7 passes through the fiber through-hole 4b of the intermediate body 4 and is fixed thereafter, while the other end is fixed to one side of the fixing member 8, which can move with tension. The other side of the fixing member 8 has a pulley rope 12 that passes around the first pulley 13 and is connected to the intermediate connecting block 11.

[0072] One end of the third dielectric elastomer fiber 9 and the fourth dielectric elastomer fiber 10 are connected to the fiber fixing block 14, and the other end is connected to the intermediate connecting block 11; the fiber fixing block 14 is located at the tension spring end 1a.

[0073] Furthermore, the first dielectric elastomer fiber 6 and the second dielectric elastomer fiber 7 are on the same horizontal plane, and the third dielectric elastomer fiber 9 and the fourth dielectric elastomer fiber 10 are on the same plane. The two are connected by the first pulley 13 to form an upper and lower two-layer structure.

[0074] Furthermore, the first dielectric elastomer fiber 6, the second dielectric elastomer fiber, the third dielectric elastomer fiber 9, and the fourth dielectric elastomer fiber 10 together form an antagonistic relationship with the tension spring 3 at the intermediate plate 4.

[0075] In Examples 1 and 2:

[0076] The driver base has one hole on the left and two perforated seats on the right. The base is 3D printed from PLA material. They are respectively: The bottom thickness is 2mm. There is a thin wire fixing hole on the left side baffle and two perforated bases on the right side. The hole on the left side is a 1mm diameter through hole located in the center of the left side. The height of the right base is 8mm and it has a 2mm diameter through hole. The through hole is 5mm away from the base and is used to connect the fastener and fix the fiber.

[0077] A thin polyethylene cord is connected to the base on one side and a tension spring on the other. The cord is made of thin polyethylene thread with a diameter of 0.35mm. The left side of the cord is 10mm long. The left side of the cord passes through the left through-hole in the base and is knotted, making its width 1mm wider than the through-hole diameter. The right side of the cord is connected to the tension spring. The right side of the cord is knotted in the middle, passes through a 1mm diameter through-hole in the middle plate, and is secured. The left end of the cord is connected to the tension spring, transferring the spring's force to the middle plate to counteract the fibers.

[0078] The tension spring has its two ends connected to thin ropes and is in a pre-stretched state. The tension spring is made of spring steel. It has a thickness of 0.4*5*20 and a stiffness coefficient of 0.105N / mm. The left side is connected to the base by a thin rope, and the right side is connected to the middle plate by a thin rope. The middle plate antagonizes the fibers.

[0079] The middle plate is used to connect the thin rope to the fiber. for The center has a hole with a diameter of 1mm and a depth of 8mm for connecting to a thin rope. The left and right holes have fiber holes with a diameter of 2.2mm and a depth of 8mm for passing through and securing fibers. The center distance between the two fiber holes on the left and right is 6mm. At the bottom of the three holes, there are additional through holes with a diameter of 0.8mm and a depth of 2mm. The middle hole is used to pass through the thin rope and tie a knot to secure it. The holes on both sides are used to pass wires to supply power to the fibers.

[0080] The high-molecular-weight polyethylene rope is connected to the intermediate plate on one side and output to the outside on the other.

[0081] Dielectric elastomer fibers are in a pre-stretched state;

[0082] Fasteners secure the fibers to the base.

[0083] The intermediate connecting block in Example 2 is used to connect two sections of dielectric elastomer pulley rope, and is used to connect the intermediate connecting block and the lower fixing pulley.

[0084] Example 3

[0085] Existing dielectric elastomer actuators have significant limitations in output force and displacement. To address this issue, this invention employs a multi-layer stacking method to enhance the output force of the fibers and uses CNTs as flexible, stretchable electrodes, connected to a high-voltage amplifier via copper wires. The specific structure is as follows: Figure 6 As shown.

[0086] After the structure is stacked, the sheet-like film is rolled into a roll. This operation increases axial displacement and saves radial space, facilitating installation. The fiber structure is as follows: Figure 7 As shown.

[0087] Figure 6 This is a schematic diagram of a stacked structure, which uses CNT electrodes to hold dielectric elastomers, with copper wires leading out. Figure 7 These are schematic diagrams of fiber structures, where a) is the internal structure of the fiber; b) is a schematic diagram of the fiber; and c) is a photograph of the actual fiber.

[0088] The dielectric layer size of the fiber before winding is The size of the electrode region is And an electrode area is left. This fiber is used to connect to copper wires. The electrode thickness is negligible. A 12.5mm non-deformable area is reserved on each of the left and right sides to pre-stretch and fix the ends of the fiber. A 5mm non-deformable area is reserved on each of the top and bottom sides to prevent short circuits caused by contact between the electrodes. After winding, the fiber, excluding the fixed portion, is approximately 100mm long and 1.9mm in diameter. Ignoring creep and hysteresis, its equivalent stiffness coefficient is 0.1N / mm. The left side of the fiber is glued to the middle plate and antagonizes the thin rope on its left side through the middle plate. The right side is glued to the fixing component, allowing it to be fixed to the bases on both sides after pre-stretching.

[0089] The dimensions of the fastener are There is a 2mm diameter through hole on the upper right side for easy fixing to the base with a pin, and there is a hole at the bottom. The holes facilitate the output of fine ropes.

[0090] Example 4

[0091] When operating with the technical solution of Example 1, after the driver is installed according to the above process, the fiber and the string are antagonistic to each other, and the fiber is in a pre-stretched state with a pre-stretch of 20%, and the force on a single fiber is approximately 1.7N. After energization, the tension of the fiber decreases under the action of Maxwell stress, and the decrease is equal to the resistance force that the fiber can generate, with a maximum resistance force of 0.9N. At this time, the spring tension is greater than the tension of the two fibers, the spring contracts, and the string is pulled outward. Furthermore, after testing, the tension on the string is approximately 0.3N when the driver slowly pulls the index finger metacarpophalangeal joint of the dexterous hand prototype. Based on the above process, the analysis is as follows:

[0092] Assume the tensile force of a single fiber in a steady state when no power is applied. Spring tension Tension on the rope When the two fibers antagonize the spring, there is

[0093] + = (1)

[0094] Assume that the fiber tension decreases after energizing. Fiber stiffness coefficient Spring stiffness coefficient The displacement is x, and we have

[0095] (2)

[0096] Calculation yields

[0097]

[0098] With fixed fiber and spring parameters, the output displacement of the actuator is related to its output force. Under no-load conditions at the output end, a 6mm output displacement can be achieved. With a rope tension of 0.3N, the output displacement is approximately 4.9mm, which can drive a joint with a 4mm radius shaft to rotate 70°. Under different driving voltages and spring stiffness coefficients, the actual maximum output displacement and output force of the actuator are as follows: Figure 8 As shown.

[0099] Example 5

[0100] A dexterous hand driven by a dielectric elastomer includes an arm, a palm, and fingers. Each finger has three joints, arranged sequentially from the palm towards the fingertip: a metacarpophalangeal joint, a proximal joint, and a distal joint. The arm internally houses an integrated base plate 15 and multiple sets of dielectric elastomer actuator units. These actuator units are fixedly mounted on the integrated base plate 15. Each set of actuator units includes a fibrous dielectric elastomer actuator, a second pulley 20, and a tendon 19. Each set of actuator units independently drives one degree of freedom of the dexterous hand, and each actuator unit operates independently without interference. A pulling assembly is formed, wherein one end of the tendon cord 19 is fixedly connected to the end of the tension spring 3 away from the tension spring end 1a, and the other end of the tendon cord 19 passes through the through hole of the tension spring 3 and the tension spring end 1a in sequence and then passes around the second pulley 20, and the other end of the tendon cord 19 is connected to or integrally formed with the free end 5a of the second high molecular weight polyethylene thin rope 5; the dexterous hand is configured with 14 degrees of freedom, of which each of the four fingers is configured with three degrees of freedom and the thumb is configured with two degrees of freedom. The distal joints of the four fingers are passive degrees of freedom and are linked with the proximal joints without independent driving components. Each metacarpophalangeal joint, proximal joint and thumb joint is configured with an independent dielectric elastomer actuator unit to achieve active driving; each Two sets of pulling components are configured for each finger. One set of pulling components is installed at the proximal and distal joints of the finger, and the other set is installed at the metacarpophalangeal joint. The tendon cord 19 of the pulling components passes through the wrist of the hand and is arranged on the back of the hand. A fixing base for fixing the fibrous dielectric elastomer actuator is provided on the left side of the integrated base plate 15, and a fixed pulley is provided on the right side of the integrated base plate 15. Through holes for fixing are opened on both sides of the integrated base plate 15 corresponding to each driving unit. The integrated base plate 15 completes the positioning and fixing of multiple sets of dielectric elastomer actuator units through the through holes on both sides, and realizes the turning of the tendon cord 19 in conjunction with the fixed pulley on the right side. The transmission is reversed, and the two ends of the tendon cord 19 driving the same degree of freedom are connected and engaged. The finger adopts a tendon cord 19 driving structure. Each tendon cord 19 is wrapped around the joint of the corresponding finger and fixedly connected to the joint. The bending and repositioning of the finger joint can be achieved by pulling the two ends of the tendon cord 19. When the free end 5a of the second high molecular weight polyethylene cord 5 is pulled to the left, it drives the corresponding finger joint to bend. At the same time, the tendon cord 19 is passively pulled to the right. When the tendon cord 19 is pulled to the left, it drives the corresponding finger to reposition and straighten. The tension spring 3 is nested and engaged with the tendon cord 19. The through hole at the end 1a of the tension spring plays a limiting and guiding role for the tendon cord 19, ensuring the motion stability of the tendon cord 19 during the extension, contraction and pulling process.When powered on, tension is applied to the tendon cord 19 on the palm side to bend the finger. The tendon cord 19 on the back side of the hand loops around a fixed pulley and engages with the spring's movable end of the dielectric elastomer actuator unit, enabling synchronous movement of the tendon cords 19 on both sides of the finger. When powered off, the tension spring 3 returns to its original length and drives the tendon cord 19 on the back side of the hand to move, thus straightening and resetting the finger.

[0101] A dexterous hand includes the arm, palm, and fingers. The fingers have three joints, which are the metacarpophalangeal joint, proximal joint, and distal joint from the palm to the fingertip.

[0102] Multiple sets of dielectric elastomer actuator units are fixed on the integrated base plate 15 inside the arm. Each set of dielectric elastomer actuator units includes the fibrous dielectric elastomer actuator, the second pulley 20 and the tendon rope 19. One end of the tendon rope 19 is fixedly connected to the end of the tension spring 3 away from the tension spring end 1a. The other end of the tendon rope 19 passes through the through hole on the entire tension spring 3 and the tension spring end 1a in sequence, and then passes around the second pulley 20. It is connected to or integrally formed with the free end 5a of the second high molecular weight polyethylene thin rope 5 to form a pulling component.

[0103] Each set of dielectric elastomer actuators acts as an individual actuator to drive one degree of freedom of the dexterous hand. The dexterous hand has a total of 14 degrees of freedom: three for each of the four fingers and two for the thumb. The distal joints of the four fingers are passive degrees of freedom that are linked to the proximal joints, while the rest are active degrees of freedom.

[0104] Each finger has two sets of pulling components, one set fixed at the proximal and distal joints, and the other set fixed at the metacarpophalangeal joint; the tendon cord 19 passes through the palm and exits at the wrist, located on the back of the hand; when the free end 5a of the cord is pulled to the left, it causes the joint to bend, and at the same time the tendon cord 19 is pulled to the right; when the tendon cord 19 is pulled to the left, the finger returns to its original position.

[0105] The actuator is used to control a dexterous hand, therefore the structure of the fingers needs to be designed, such as... Figure 12 As shown, the finger has three joints, from left to right: the metacarpophalangeal joint, the proximal joint, and the distal joint. The tendon cord 19 and the free end 5a of the thin string are the two ends of a single rope, which successively wraps around the proximal and distal joints and is fixed at the distal joint. When the free end 5a of the thin string is pulled to the left, it causes both the proximal and distal joints to bend simultaneously, while the tendon cord 19 is also pulled to the right. When the tendon cord 19 is pulled to the left, the finger returns to its original position. Similarly, the tendon cord 19, which wraps around the metacarpophalangeal joint and is fixed, and the free end 5a of the thin string can be pulled to achieve bending and straightening respectively.

[0106] As mentioned above, each finger extends 4 tendon cords, which pass through the palm and emerge at the wrist. To reduce friction, the inside of the palm has a hollow structure, and rounded corners are designed at the bends of the tendon cords to reduce friction.

[0107] The actuators are modularly designed, with each single-layer actuator capable of independently driving one degree of freedom in the dexterous hand, facilitating installation and replacement. The designed dexterous hand has a total of 14 degrees of freedom: three for each of the four fingers and two for the thumb. The distal joints of the four fingers are passive degrees of freedom, while the rest are active degrees of freedom. Each active degree of freedom uses one actuator, meaning that a total of ten actuators are required to operate simultaneously, necessitating the design of the forearm integration.

[0108] To integrate the drive unit, a double-layer design is adopted. The base is placed on the lower layer of the drive unit, and each actuator is fixed on the base. A fixed pulley is arranged on the right side to connect the two ends of the tendon ligament. (See diagram below.) Figure 10 As shown in the figure, the first dielectric elastomer driving unit 16, the second dielectric elastomer driving unit 17, and the third dielectric elastomer driving unit 18 are arranged sequentially on the base plate with an adjacent interval of 4mm. The fibers of each driving unit are pre-stretched and fixed before being fixed in sequence.

[0109] The assembly method on the right is as follows Figure 11 As shown, a first polyethylene cord 2 is connected to the right side of the tension spring 3. The cord passes through a perforated plate and is knotted for fixation. The length of the plate is greater than the diameter of the through hole on the right end 1a of the tension spring, thereby fixing the first polyethylene cord 2 to the right end 1a of the tension spring. A tendon cord 19 passes over the through hole on the end 1a of the tension spring, passes through the tension spring 3, and is tied to the left side of the tension spring away from the end 1a. The other side of the tendon cord passes through the through hole, wraps around the second pulley 20, and connects to the tendon cord on the back of the hand.

[0110] When the fiber is energized, the actuator operates, and the tension spring causes the finger to bend, moving along with the tendon ligament on the back of the hand. After the power is cut off, the dielectric elastomer fiber causes the tension spring to return to its original position, and at the same time, the force is transmitted through tendon ligament 19 to the tendon ligament on the back of the hand, causing the finger to return to its original position.

[0111] The forearm has a diameter of 74mm and a length of 260mm, slightly larger than an adult's forearm. Ten actuator units are arranged in three layers, each connected to a set of thin cords extending from the wrist. Depending on the forearm diameter, the number of units in each layer is 3, 4, and 3 respectively. A bracket is designed on the forearm to hold the three layers of actuators, with threaded holes for secure mounting. A schematic diagram of the forearm and a prototype integration diagram are shown below. Figure 9 As shown.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fibrous dielectric elastomer actuator, characterized in that: The actuator includes an actuator base (1), an intermediate plate (4), a tension spring (3), and dielectric elastomer fibers; One end of the driver base (1) is a tension spring end (1a), and the other end is a fiber end (1b). One end of the tension spring (3) is connected to the tension spring end (1a) via a first high-molecular-weight polyethylene rope (2), and the other end of the tension spring (3) is connected to the intermediate plate (4) via a second high-molecular-weight polyethylene rope (5). One end of the second high-molecular-weight polyethylene rope (5) is connected to the end of the tension spring (3) away from the tension spring end (1a), and the other end passes through the through hole of the intermediate plate (4) and is knotted in the middle. The end that extends and passes through the limiting end (1b) is the free end (5a) of the rope, which is used for external output. One end of the dielectric elastomer fiber is connected to the intermediate plate (4), and the other end is fixed to the fastener (8); The force of the tension spring (3) and the force of the dielectric elastomer fiber antagonize each other at the intermediate plate (4).

2. The fibrous dielectric elastomer actuator according to claim 1, characterized in that: The dielectric elastomer fiber includes two sets: a first dielectric elastomer fiber (6) and a second dielectric elastomer fiber (7). One end of each fiber passes through the fiber through hole (4b) of the intermediate body (4) and is fixed thereon. The other end is fixed on the fixing member (8) and the fixing member (8) is fixedly set at the fiber end (1b).

3. The fibrous dielectric elastomer actuator according to claim 2, characterized in that: Assume the tensile force of a single dielectric elastomer fiber in its steady state when no power is applied. Spring tension Tension on the thin polyethylene rope When dielectric elastomer fibers antagonize springs: + = （1）； Assume that the tensile force of a single dielectric elastomer fiber decreases after energization. Fiber stiffness coefficient Spring stiffness coefficient Given a displacement of x, we have: （2）； The calculation yielded: ； This refers to obtaining the distance that the dielectric elastomer fiber can be pulled before and after being energized.

4. The fibrous dielectric elastomer actuator according to claim 1, characterized in that: The dielectric elastomer fibers include four groups: a first dielectric elastomer fiber (6), a second dielectric elastomer fiber (7), a third dielectric elastomer fiber (9), and a fourth dielectric elastomer fiber (10). One end of the first dielectric elastomer fiber (6) and the second dielectric elastomer fiber (7) passes through the fiber through hole (4b) of the intermediate body (4) and is fixed, while the other end is fixed to one side of the fixing member (8). The fixing member (8) can move with the tension. The pulley rope (12) on the other side of the fixing member (8) passes around the first pulley (13) and is connected to the intermediate connecting block (11). One end of the third dielectric elastomer fiber (9) and the fourth dielectric elastomer fiber (10) are connected to the fiber fixing block (14), and the other end is connected to the intermediate connecting block (11); the fiber fixing block (14) is located at the tension spring end (1a).

5. The fibrous dielectric elastomer actuator according to claim 4, characterized in that: The first dielectric elastomer fiber (6) and the second dielectric elastomer fiber (7) are on the same horizontal plane, and the third dielectric elastomer fiber (9) and the fourth dielectric elastomer fiber (10) are on the same plane. The two are connected by the first pulley (13) to form an upper and lower two-layer structure.

6. The fibrous dielectric elastomer actuator according to claim 5, characterized in that: The first dielectric elastomer fiber (6), the second dielectric elastomer fiber, the third dielectric elastomer fiber (9), and the fourth dielectric elastomer fiber (10) together form an antagonistic relationship with the tension spring (3) at the intermediate plate (4).

7. A dexterous hand employing the fibrous dielectric elastomer actuator according to any one of claims 1-6, characterized in that: It includes the arm, palm, and fingers, and the fingers are provided with three joints, which are the metacarpophalangeal joint, the proximal joint, and the distal joint in the direction from the palm toward the fingertip; The arm is provided with an integrated base plate (15) and multiple sets of dielectric elastomer actuator units. The multiple sets of dielectric elastomer actuator units are fixedly installed on the integrated base plate (15). Each set of dielectric elastomer actuator units includes the fibrous dielectric elastomer actuator, a second pulley (20) and a tendon rope (19). In each of the dielectric elastomer drive units, one end of the tendon cord (19) is fixedly connected to the end of the tension spring (3) away from the tension spring end (1a), and the other end of the tendon cord (19) passes through the through hole of the tension spring (3) and the tension spring end (1a) in sequence and then passes around the second pulley (20). The other end of the tendon cord (19) is connected to or integrally formed with the free end (5a) of the second high molecular weight polyethylene cord (5); the free end (5a) of the cord and the tendon cord (19) constitute a pulling assembly. The dexterous hand is configured with 14 degrees of freedom, with three degrees of freedom for each of the four fingers and two degrees of freedom for the thumb. The distal joints of the four fingers are passive degrees of freedom and are linked with the proximal joints, while the remaining degrees of freedom are active degrees of freedom. The integrated base plate (15) has a fixing base for fixing the fibrous dielectric elastomer actuator on the left side, and a second pulley (20) is provided on the right side of the integrated base plate (15). The integrated base plate (15) has through holes for fixing on both sides corresponding to each driving unit. The second pulley (20) is used to connect the two ends of the tendon rope (19) driving the same degree of freedom. Each finger is equipped with two sets of pulling components. One set of the pulling components is installed at the proximal and distal joints of the finger, and the other set of the pulling components is installed at the metacarpophalangeal joints of the finger. The tendon cord (19) and the free end (5a) of the thin rope of the pulling component pass through the wrist position of the palm, and the tendon cord (19) is arranged on the back of the hand. The pulling component is wound around the joint of the corresponding finger and fixedly connected to the joint. The bending and repositioning of the finger joint is achieved by pulling the tendon rope (19) and the free end (5a) of the thin rope. When the power is on, the finger is bent by applying a pulling force to the free end (5a) of the thin rope on the palm side. The tendon rope (19) on the back side of the hand passes around the fixed pulley and is linked with the spring movable end of the dielectric elastomer actuator unit to achieve synchronous movement of the tendon rope (19) and the free end (5a) of the thin rope on both sides of the finger. When the power is off, the tension spring (3) returns to its original length and drives the tendon rope (19) on the back side of the hand to move, thereby achieving finger straightening and repositioning.

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