Biomimetic spinal stiffness-varying device based on electrorheological elastomer

Abstract

The application discloses a bionic spine variable stiffness device based on electrorheological elastomer, which is composed of lattice rheological intelligent structure modules and rotary variable stiffness joint modules in cross series connection, and four PE ropes are used to connect the modules into a whole. The ends of the ropes are fixed on the rotating drum of the motor shaft, the extension and retraction of the ropes are controlled by the rotation of the motor, so that the movement of the bionic spine is controlled. Flexible electrodes and electrorheological elastomers are alternately stacked in the honeycomb lattice structure printed by the SLA process, so that the lattice rheological intelligent structure is formed. The rotary variable stiffness joint adopts a cross bearing as a connecting joint to support the bending movement of the spine structure in four directions. The joint is filled with electrorheological elastomer, and the rotation of the joint is controlled by the rotation of the gear driven by the motor. The combination of the lattice rheological intelligent structure and the rotary variable stiffness joint realizes the bending variable stiffness and rotary variable stiffness control of the bionic spine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent flexible structure, and particularly relates to a bionic spine variable stiffness device based on electrorheological elastomer. BACKGROUND

[0002] In a complex time-varying strong disturbance environment, there is a risk of collision and damage when an unmanned system directly lands for charging or fueling, so cross-domain docking of intelligent unmanned systems is a common technical problem to ensure sea-land-air cross-domain operations. Taking the charging docking of an amphibious unmanned vehicle and a UAV in a complex sea state as an example, a traditional rigid manipulator is prone to rigid collision during docking, which has a high risk of failure. The use of a flexible docking mechanism has the advantages of large fault tolerance, strong load capacity, and high disturbance self-adaptive capability, which can provide support for the endurance of the UAV.

[0003] Continuous bionic spines have good flexibility due to the use of flexible materials, but they also face challenges such as low stiffness and insufficient load capacity. To solve these problems, a variable stiffness mechanism needs to be introduced into the bionic spine. Currently, the variable stiffness methods mainly include antagonistic variable stiffness, friction variable stiffness, and material variable stiffness.

[0004] Antagonistic variable stiffness usually uses a pneumatic control method, which is simple to operate and lightweight. However, it has a high manufacturing cost, slow response, and the risk of air leakage. The most common friction variable stiffness is the particle blocking method. It uses the friction between particles to enhance the hardness of the system, which is simple and low-cost. However, the particles will gradually wear out over time. New materials such as shape memory alloys (SMA) can also be used to achieve material variable stiffness, but SMA has the risk of fatigue failure, which affects the service life of the mechanism. In addition, the use of origami structures to adjust stiffness can perform a variety of actions, but the design of origami structures is complex and the structure is easily damaged. SUMMARY

[0005] The purpose of the present application is to provide a bionic spine variable stiffness device based on electrorheological elastomer to solve the problems existing in the prior art. By using a dot matrix structure to simulate the spine vertebrae and electrorheological elastomer to replace the soft tissue of the spine, the high degree of freedom is maintained while the adjustable stiffness of the bionic spine is achieved.

[0006] To achieve the above purpose, the present application provides the following scheme:

[0007] The application provides a bionic spine variable stiffness device based on electrorheological elastomer, which comprises a rotating drum, a support, a spring, a rotary variable stiffness joint, a dot matrix rheological intelligent structure, a joint support base, a joint upper support disc and a rope.

[0008] The rotary variable stiffness joint comprises a rotary motor, a joint connecting frame, a universal joint cross bearing, a cross bearing support frame, an electrorheological elastomer and an electrode.

[0009] The dot matrix rheological intelligent structure comprises a honeycomb structure shell, an electrorheological elastomer and a flexible electrode.

[0010] Preferably, the rope is provided with four ropes, and the four ropes are evenly distributed in the circumferential direction with the shaft center of the joint support base and the joint upper support disc as the center.

[0011] Preferably, each rope corresponds to one rotating drum, four rotating drums are connected to one rope drive motor through a shaft coupling respectively, and the four rope drive motors are installed on the side wall of the support.

[0012] Preferably, a gear is fixed on the shaft of the rotary motor, the gear on the shaft of the rotary motor is engaged with the gear teeth on the joint connecting frame, and the rotary motor drives the joint connecting frame to rotate.

[0013] Preferably, the cross bearing support frame is connected to the joint connecting frame through a pin.

[0014] Preferably, the top of the joint support base is provided with protruding sector blocks, and the sector blocks are used to space mounting spaces for placing the electrorheological elastomer between the joint support base and the joint connecting frame.

[0015] Preferably, the top of the honeycomb structure shell is provided with a top cover, and the top cover is provided with clamping grooves matched with the clamping blocks of the top of the honeycomb structure shell.

[0016] Preferably, the copper wire is fixed on the flexible electrode by means of the conductive copper foil tape, and the flexible electrode is electrified.

[0017] Preferably, the honeycomb structure shell is a regular hexagon, the side walls of the honeycomb structure shell are all curved beam structures, the material of the honeycomb structure shell is rubber, and the honeycomb structure shell is a honeycomb lattice structure printed by an SLA process.

[0018] The present application has the following beneficial technical effects relative to the prior art:

[0019] The bionic spine variable stiffness device based on electrorheological elastomer provided by the present application adopts electrorheological elastomer, which is an advanced product based on electrorheological effect technology, and the compression modulus and shear modulus of which can be adjusted by applying an external electric field, and has the characteristics of reversible adjustment, fast response, low energy consumption and the like, and has a wide application prospect in the engineering field.

[0020] The present application adopts a honeycomb lattice structure as the framework of the spine, fills the electrorheological elastomer in the inside to simulate the soft tissue of the biological spine, fills the electrorheological elastomer in the bionic joint, and uses a motor-gear transmission mode to realize the rotation variable stiffness adjustment of the joint, and uses a rope driving mechanism to simulate the ligaments and muscles around the spine.

[0021] The bionic spine is composed of cross-series connection of lattice rheological intelligent structure modules and rotation variable stiffness joint modules, 4 PE ropes are used to connect the modules into a whole, and a spring is arranged between each module. The whole spine structure is fixed on the bottom support. The ends of the ropes are fixed on the rotating drum of the motor shaft, the rotation of the motor is used to control the winding and unwinding of the ropes, so as to control the movement of the bionic spine. The flexible electrode and the electrorheological elastomer are alternately stacked in the honeycomb lattice structure printed by the SLA process, so as to form the lattice rheological intelligent structure. The cross bearing is used as the connecting joint of the rotation variable stiffness joint, and supports the bending movement of the spine structure in four directions. The electrorheological elastomer is filled in the joint, and the rotation of the joint is controlled by the rotation of the gear driven by the motor. The combination of the lattice rheological intelligent structure and the rotation variable stiffness joint realizes the bending variable stiffness and rotation variable stiffness control of the bionic spine. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed in the embodiments will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0023] Figure 1 A perspective structural schematic diagram of a bionic spine variable stiffness device based on electrorheological elastomers in the present application;

[0024] Figure 2 A perspective structural schematic diagram of a bionic spine variable stiffness device in a bending state in the present application;

[0025] Figure 3 A perspective structural schematic diagram of a rotary variable stiffness joint in the present application;

[0026] Figure 4 A perspective structural schematic diagram of a dot matrix rheological intelligent structure in the present application;

[0027] Figure 5 A sectional view of the dot matrix rheological intelligent structure in the present application;

[0028] Figure 6 A structural schematic diagram of elastomer variable stiffness in a bending state in the present application;

[0029] Figure 7 An assembly diagram of electrorheological elastomer two and flexible electrodes in the present application;

[0030] In the figure: 1, rotating drum; 2, shaft coupling; 3, rope drive motor; 4, support; 5, spring; 6, rotary variable stiffness joint; 7, rotary motor; 8, dot matrix rheological intelligent structure; 9, rope; 10, joint support base; 11, joint connecting frame; 12, universal joint cross bearing; 13, joint upper support disc; 14, gear; 15, cross bearing support frame; 16, electrorheological elastomer one; 17, electrode; 18, top cover; 19, honeycomb structure shell; 20, electrorheological elastomer two; 21, flexible electrode; 22, copper wire; 23, conductive copper foil tape. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the scope of protection of the present application.

[0032] The purpose of the present invention is to provide a bionic spinal column variable stiffness device based on electrorheological elastomer to solve the problems existing in the prior art.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The bionic spinal column variable stiffness device based on electrorheological elastomer in this embodiment is as follows: Figures 1-7 As shown, it includes a rotating drum 1, a bracket 4, a spring 5, a rotationally variable stiffness joint 6, a lattice rheological intelligent structure 8, a joint supporting chassis 10, a joint upper supporting plate 13 and a rope 9; a plurality of joint supporting chassis 10 and a joint upper supporting plate 13 are provided, and are alternately spaced at the top of the bracket 4, the rotationally variable stiffness joint 6 is provided on the top of the joint supporting chassis 10, the lattice rheological intelligent structure 8 is provided on the top of the joint upper supporting plate 13, and the outer peripheries of the joint supporting chassis 10 and the joint upper supporting plate 13 are distributed with opposite through holes, and the rope 9 passes through the through holes on each joint supporting chassis 10 and each joint upper supporting plate 13 from top to bottom and is connected to the rotating drum 1, and the retraction and extension of the rope 9 is controlled by the rotating drum 1, and the rope 9 located between the joint supporting chassis 10 and the joint upper supporting plate 13 is sleeved with a spring 5 to play a buffering and vibration reduction role;

[0035] The rotational variable stiffness joint 6 includes a rotary motor 7, a joint connecting frame 11, a universal joint cross bearing 12, a cross bearing support frame 15, an electrorheological elastomer 16 and an electrode 17; the bottom of the joint connecting frame 11 is rotatably connected to the joint support chassis 10, and the joint connecting frame 11 is controlled to rotate by the rotary motor 7. The universal joint cross bearing 12 is connected between the joint connecting frame 11 and the joint upper support plate 13 through the cross bearing support frame 15. The electrorheological elastomer 16 and the electrode 17 are arranged between the joint connecting frame 11 and the joint support chassis, and the electrode 17 is wrapped on both sides of the electrorheological elastomer 16. The stiffness of the electrorheological elastomer is changed by applying voltage, thereby realizing the rotational variable stiffness of the bionic spine;

[0036] The lattice rheological intelligent structure 8 includes a honeycomb structure shell 19, an electrorheological elastomer 20 and a flexible electrode 21; a plurality of electrorheological elastomers 20 and flexible electrodes 21 are provided and alternately stacked in the honeycomb structure shell 19. The stiffness of the electrorheological elastomer is changed by applying voltage, thereby realizing the compression stiffness change of the bionic spine.

[0037] In this specific embodiment, four ropes 9 are provided, and the four ropes 9 are evenly distributed circumferentially with the axis of the joint support chassis 10 and the joint upper support plate 13 as the center, thereby controlling the forward, backward, left and right movements of the robotic arm.

[0038] In the embodiment, each rope 9 corresponds to a rotating drum 1, and the four rotating drums 1 are connected to four rope-driven motors 3 respectively through couplings 2, and the four rope-driven motors 3 are installed on the side walls of the support 4.

[0039] In the embodiment, a gear 14 is fixed on the shaft of the rotating motor 7, the gear 14 on the shaft of the rotating motor 7 is engaged with the gear teeth on the joint connecting frame 11, and the rotating motor 7 drives the joint connecting frame 11 to rotate.

[0040] In the embodiment, the cross bearing support frame 15 is connected to the joint connecting frame 11 through a pin.

[0041] In the embodiment, the top of the joint support base plate 10 is provided with a protruding sector block, and the sector block is used to separate an installation space for placing the electrorheological elastomer between the joint support base plate 10 and the joint connecting frame 11.

[0042] In the embodiment, the top of the honeycomb structure shell 19 is provided with a top cover 18, and the top cover 18 is provided with a clamping groove matched with the clamping block on the top of the honeycomb structure shell 19.

[0043] In the embodiment, the copper wire 22 is fixed on the flexible electrode 21 through the conductive copper foil tape 23, and the flexible electrode 21 is powered.

[0044] In the embodiment, the honeycomb structure shell 19 is a regular hexagon, the side walls of the honeycomb structure shell 19 are all curved beam structures, the material of the honeycomb structure shell 19 is rubber, and the honeycomb structure shell 19 is a honeycomb lattice structure printed by an SLA process.

[0045] The bionic spine adopts a honeycomb lattice structure as a backbone, fills the inside with an electrorheological elastomer to simulate the soft tissue of a biological spine, fills the bionic joint with the electrorheological elastomer as well, uses a motor-gear 14 transmission mode to realize the rotation stiffness adjustment of the joint, and uses a rope 9 driving mechanism to simulate the ligaments and muscles around the spine.

[0046] The bionic spine is composed of a lattice rheological intelligent structure 8 module and a rotation stiffness joint 6 module in cross connection, four PE material ropes 9 are taken (the PE material can reduce the friction between the ropes and the holes, and has the characteristics of not conducting electricity), one end of the rope 9 is fixed on the first joint, and then the rope 9 is sequentially threaded through the rope holes on the joints. A spring 5 is placed between the rope 9 and the joint after passing through each joint, which plays a supporting, buffering and damping role. The whole spine structure is fixed on the bottom support 4. The step motor is installed on the bottom support 4, the end of the rope 9 is fixed on the rotating drum 1, the rotation of the step motor is used to control the winding and unwinding of the rope 9, so as to control the bending movement of the whole bionic spine.

[0047] Electro-rheological fluid is a new type of material that can change its properties under an applied electric field. The shear storage modulus, compression modulus and other properties of the elastomer will increase, and will return to the initial state after the electric field is removed. The response time to the electric field is in the order of milliseconds.

[0048] The lattice rheological smart structure 8 is composed of a honeycomb lattice structure, an electro-rheological elastomer, and a flexible electrode 21. The honeycomb lattice structure is printed by SLA technology, and then the flexible electrode 21 and the cut electro-rheological elastomer are alternately stacked to ensure that each layer of the electrode 17 and the elastomer are closely attached. At the same time, the electrodes 17 at both ends of each elastomer cannot be connected to the same level of the power supply to prevent short circuit, so the electrodes 17 are connected to the power supply in the order of "positive-negative-positive-…", ensuring that the electro-rheological elastomer can change its stiffness and damping characteristics under the action of voltage, thereby realizing the stiffness adjustment of the bionic rheological smart structure. The wires connected to the same end of the power supply are placed on the same side of the structure and are passed through the holes of the honeycomb lattice structure, which is convenient for subsequent voltage application.

[0049] The honeycomb lattice structure is made of rubber material and has insulation. The curved beam structure is used as the side wall of the lattice structure, which has high bearing capacity. SLA technology is used for the molding process of the lattice structure. A specific wavelength and intensity of ultraviolet light is used to irradiate the liquid photosensitive resin, which undergoes polymerization reaction to generate a three-dimensional honeycomb lattice structure entity.

[0050] The rotary variable stiffness joint 6 is composed of a support frame, a joint connecting frame 11, a universal joint cross bearing 12, a cross bearing support frame 15, a rotary motor 7, a gear 14, an electro-rheological elastomer, and an electrode 17. The cross bearing is used as the connecting joint of the lattice rheological structure, which can effectively support the bending movement of the spine structure in four directions, providing the flexibility and stability required by the bionic spine, while maintaining the compactness and functionality of the overall design. The cross bearing support frame 15 is fixed to the joint connecting frame 11 and the upper support disc, and the joint connecting frame 11 and the upper support disc are connected by the universal joint cross bearing 12. The joint connecting frame 11 is assembled with the joint support bottom disc 10 through the bearing. The joint connecting frame 11 has a gear tooth, which is engaged with the gear 14 on the motor driving shaft, and the rotation of the gear 14 is controlled by the motor, thereby controlling the rotation of the joint. The joint connecting frame 11 and the support bottom disc are filled with electro-rheological elastomer, and each cell contains two pieces of elastomer. The electrodes 17 are arranged between the elastomers, and the stiffness of the electro-rheological elastomer changes by applying voltage, thereby realizing the variable stiffness control of the joint rotation.

[0051] The principles and implementation manners of the present application are described by using specific examples, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A bionic spinal column variable stiffness device based on electrorheological elastomer, characterized by: The invention comprises a rotating drum, a bracket, a spring, a rotationally variable stiffness joint, a lattice rheological intelligent structure, a joint supporting chassis, a joint upper supporting plate and a rope; the joint supporting chassis and the joint upper supporting plate are provided with a plurality of them, and are alternately arranged at intervals on the top of the bracket, the rotationally variable stiffness joint is provided on the top of the joint supporting chassis, the lattice rheological intelligent structure is provided on the top of the joint upper supporting plate, and the peripheries of the joint supporting chassis and the joint upper supporting plate are distributed with opposite through holes, the rope passes through the through holes on each of the joint supporting chassis and each of the joint upper supporting plates in sequence from top to bottom and is connected to the rotating drum, the rotating drum controls the retraction and extension of the rope, and the ropes located between the joint supporting chassis and the joint upper supporting plate are all sleeved with the springs; The rotational variable stiffness joint includes a rotary motor, a joint connecting frame, a universal joint cross bearing, a cross bearing support frame, an electrorheological elastomer and electrodes; the bottom of the joint connecting frame is rotatably connected to the joint support chassis, the joint connecting frame is controlled to rotate by the rotary motor, the universal joint cross bearing is connected between the joint connecting frame and the joint upper support plate through the cross bearing support frame, the electrorheological elastomer and electrodes are arranged between the joint connecting frame and the joint support chassis, and the electrodes are wrapped around both sides of the electrorheological elastomer, and the stiffness of the electrorheological elastomer is changed by applying voltage, thereby realizing the rotational variable stiffness of the bionic spine; The lattice rheological intelligent structure includes a honeycomb structure shell, an electrorheological elastomer 2 and a flexible electrode; the electrorheological elastomer 2 and the flexible electrode are provided in plurality and alternately stacked in the honeycomb structure shell. The stiffness of the electrorheological elastomer is changed by applying voltage, thereby realizing the compression stiffness change of the bionic spine.

2. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 1, characterized in that: There are four ropes, and the four ropes are evenly distributed circumferentially with the axis of the joint support chassis and the joint upper support plate as the center.

3. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 2, characterized in that: Each of the ropes corresponds to one of the rotating drums, and the four rotating drums are respectively connected to a rope drive motor through a coupling. The four rope drive motors are installed on the side wall of the bracket.

4. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 1, characterized in that: A gear is fixed on the shaft of the rotary motor, and the gear on the rotary motor shaft meshes with the gear teeth on the joint connecting frame, so that the rotary motor drives the joint connecting frame to rotate.

5. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 1, characterized in that: The cross bearing support frame is connected to the joint connecting frame through a pin.

6. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 1, characterized in that: A protruding fan-shaped block is provided on the top of the joint supporting chassis, and the fan-shaped block forms an installation space for placing the electrorheological elastomer between the joint supporting chassis and the joint connecting frame.

7. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 1, characterized in that: A top cover is provided on the top of the honeycomb structure shell, and a card slot is provided on the top cover to match the card block on the top of the honeycomb structure shell.

8. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 1, characterized in that: The copper wire is fixed on the flexible electrode by means of a conductive copper foil tape, and the flexible electrode is energized.

9. The electrorheological elastomer-based bionic spinal column variable stiffness device according to claim 1, characterized in that: The honeycomb structure shell is a regular hexagon, the side walls of the honeycomb structure shell are all curved beam structures, the material of the honeycomb structure shell is rubber, and the honeycomb structure shell is a honeycomb lattice structure printed by the SLA process.

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