Bionic spine variable stiffness device based on electrorheological elastomer

Abstract

The invention discloses a bionic spine variable stiffness device based on an electrorheological elastomer, a bionic spine is formed by cross series connection of dot matrix rheological intelligent structure modules and rotary variable stiffness joint modules, and four PE ropes penetrate through the modules to connect the modules into a whole. The tail end of the rope is fixed to a rotating cylinder of a motor rotating shaft, the rope is controlled to be wound and unwound through rotation of the motor, and therefore movement of the bionic spine is controlled. The flexible electrodes and the 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, and supports the bending movement of the spine structure in four directions. Electrorheological elastomers are filled in the joints, and gears are driven by motors to rotate, so that rotation of the joints is controlled. And the dot matrix rheological intelligent structure and the rotary variable stiffness joint are combined for use, so that the bending variable stiffness and rotary variable stiffness control of the bionic spine is realized.

Description

Technical Field

[0001] The invention relates to the technical field of intelligent flexible structures, in particular to a bionic spine variable stiffness device based on electrorheological elastomer. Background Art

[0002] In a complex time-varying strong disturbance environment, unmanned systems directly landing for charging or refueling are at risk of collision and damage, so cross-domain docking of intelligent unmanned systems is a common technical issue to ensure cross-domain operations of sea, land and air. Taking the charging and docking of amphibious unmanned vehicles and drones in complex sea conditions as an example, the use of traditional rigid mechanical arms is prone to rigid collision during the docking process, which poses a great risk of failure; the use of flexible docking mechanisms has the advantages of large fault tolerance margin, strong load capacity, and high disturbance adaptive ability, which can provide guarantee for the endurance of drones.

[0003] The continuous bionic spine has good flexibility due to its use of flexible materials, but it also faces the challenges of low stiffness and insufficient load-bearing capacity. In order to solve these problems, it is necessary to introduce a variable stiffness mechanism into the bionic spine. At present, the main ways of variable stiffness include: antagonistic variable stiffness, friction variable stiffness and material variable stiffness.

[0004] Antagonistic variable stiffness usually adopts pneumatic control, which is simple to operate and light in material. However, the production cost is high, the response is slow, and there is a risk of air leakage. The most common method of friction variable stiffness is the particle blocking method. The friction between particles is used to enhance the hardness of the system, which has the characteristics of simplicity and low cost. However, as the use time increases, the particles will gradually wear out. 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, origami structures are used to adjust stiffness, which can perform a variety of actions, but the design of origami structures is complex and the structure is easily damaged. Summary of the invention

[0005] The purpose of the present invention is to provide a bionic spinal variable stiffness device based on electrorheological elastomer to solve the problems existing in the above-mentioned prior art. By adopting a lattice structure to biomimetically simulate spinal vertebrae and electrorheological elastomer to biomimetically replace spinal soft tissue, the adjustability of bionic spinal stiffness is achieved while maintaining a high degree of freedom.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a bionic spine variable stiffness device based on electrorheological elastomer, comprising a rotating drum, a bracket, a spring, a rotationally variable stiffness joint, a lattice rheological intelligent structure, a joint support chassis, a joint upper support plate and a rope; the joint support chassis and the joint upper support plate are provided in plurality and are alternately arranged at intervals on the top of the bracket, the rotationally variable stiffness joint is arranged on the top of the joint support chassis, the lattice rheological intelligent structure is arranged on the top of the joint upper support plate, the joint support chassis and the joint upper support plate are provided with mutually opposite through holes on their peripheries, the rope passes through the through holes on each of the joint support chassis and each of the joint upper support 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 rope located between the joint support chassis and the joint upper support plate is sleeved with the spring;

[0008] The rotational variable stiffness joint comprises a rotating 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 rotating 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 on both sides of the electrorheological elastomer, and the stiffness change of the electrorheological elastomer is achieved by applying voltage;

[0009] 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 are alternately stacked in the honeycomb structure shell, and the stiffness of the electrorheological elastomer is changed by applying voltage, thereby realizing the compression stiffness change of the bionic spine.

[0010] Preferably, four ropes are provided, 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.

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

[0012] Preferably, a gear is fixed on the shaft of the rotating motor, and the gear on the rotating motor shaft meshes with the gear teeth on the joint connecting frame, so that the rotating 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, a protruding fan-shaped block is provided on the top of the joint supporting chassis, and the fan-shaped block is used to separate an installation space for placing the electrorheological elastomer between the joint supporting chassis and the joint connecting frame.

[0015] Preferably, a top cover is provided on the top of the honeycomb structure shell, and a card slot cooperating with a card block on the top of the honeycomb structure shell is provided on the top cover.

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

[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 SLA process.

[0018] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0019] The bionic spine variable stiffness device based on electrorheological elastomer provided by the present invention adopts electrorheological elastomer (Electrorheological Elastomer), which is an advanced product based on electrorheological effect technology. Its compression modulus and shear modulus can be adjusted by applying an external electric field. It has the characteristics of reversibility and adjustability, fast response, low energy consumption, etc., and has broad application prospects in the engineering field.

[0020] The present invention adopts a honeycomb lattice structure as the skeleton of the spine, and fills the interior with electrorheological elastomer to simulate the soft tissue of the biological spine. The bionic joints are also filled with electrorheological elastomer, and a motor-gear transmission method is used to achieve joint rotation and variable stiffness adjustment. A rope drive mechanism is used to simulate the ligaments and muscles around the spine.

[0021] The bionic spine is composed of a lattice rheological intelligent structure module and a rotational variable stiffness joint module, which are cross-connected in series. Four PE ropes are used to pass through each module to connect them into a whole, and a spring is placed between each module. The entire spine structure is fixed on the bottom bracket. The end of the rope is fixed on the rotating drum of the motor shaft, and the rotation of the motor is used to control the retraction and release of the rope, thereby controlling the movement of the bionic spine. Flexible electrodes and electrorheological elastomers are alternately stacked in the honeycomb lattice structure printed by the SLA process to form a lattice rheological intelligent structure. The rotational variable stiffness joint uses 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 elastomers, and the gears are driven to rotate by the motor to control the rotation of the joint. The combined use of the lattice rheological intelligent structure and the rotational variable stiffness joint realizes the bending variable stiffness and rotation variable stiffness control of the bionic spine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the three-dimensional structure of the bionic spine variable stiffness device based on electrorheological elastomer in the present invention;

[0024] Figure 2 It is a schematic diagram of the three-dimensional structure of the electrorheological elastomer-based bionic spine variable stiffness device in a bending state in the present invention;

[0025] Figure 3 It is a schematic diagram of the three-dimensional structure of the rotational variable stiffness joint in the present invention;

[0026] Figure 4 A schematic diagram of the three-dimensional structure of the lattice rheological intelligent structure of the present invention;

[0027] Figure 5 It is a cross-sectional view of the lattice rheological intelligent structure of the present invention;

[0028] Figure 6 It is a schematic diagram of the structure of the elastic body with variable stiffness in a bending state in the present invention;

[0029] Figure 7 It is an assembly diagram of the electrorheological elastomer 2 and the flexible electrode in the present invention;

[0030] In the figure: 1. rotating drum; 2. coupling; 3. rope-driven motor; 4. bracket; 5. spring; 6. rotational variable stiffness joint; 7. rotating motor; 8. lattice rheological intelligent structure; 9. rope; 10. joint support chassis; 11. joint connecting frame; 12. universal joint cross bearing; 13. joint upper support plate; 14. gear; 15. cross bearing support frame; 16. electrorheological elastomer 1; 17. electrode; 18. top cover; 19. honeycomb structure shell; 20. electrorheological elastomer 2; 21. flexible electrode; 22. copper wire; 23. conductive copper foil tape. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The purpose of the present invention is to provide a bionic spine 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 spine variable stiffness device based on electrorheological elastomer in this embodiment is as follows: Figure 1-Figure 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 arranged at intervals on the top of the bracket 4, the rotationally variable stiffness joint 6 is arranged on the top of the joint supporting chassis 10, the lattice rheological intelligent structure 8 is arranged 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 mutually opposite through holes, 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 in sequence and is connected to the rotating drum 1, the rotating drum 1 controls the retraction and extension of the rope 9, 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, 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, and the stiffness change of the electrorheological elastomer is realized 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, and 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 around the axis of the joint support chassis 10 and the joint upper support plate 13, so as to control the forward, backward, left and right movements of the robot arm.

[0038] In this specific embodiment, each rope 9 corresponds to a rotating drum 1 , and the four rotating drums 1 are respectively connected to a rope drive motor 3 through a coupling 2 . The four rope drive motors 3 are installed on the side wall of the bracket 4 .

[0039] In this specific embodiment, a gear 14 is fixed on the shaft of the rotary motor 7 , and the gear 14 on the shaft of the rotary motor 7 meshes with the gear teeth on the joint connecting frame 11 , so that the rotary motor 7 drives the joint connecting frame 11 to rotate.

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

[0041] In this specific embodiment, a protruding fan-shaped block is disposed on the top of the joint supporting chassis 10 , and the fan-shaped block separates an installation space for placing the electrorheological elastomer between the joint supporting chassis 10 and the joint connecting frame 11 .

[0042] In this specific embodiment, a top cover 18 is disposed on the top of the honeycomb structure shell 19 , and a card slot that cooperates with a card block on the top of the honeycomb structure shell 19 is disposed on the top cover 18 .

[0043] In this specific embodiment, the copper wire 22 is adhered and fixed to the flexible electrode 21 by means of the conductive copper foil tape 23 , so that the flexible electrode 21 is energized.

[0044] In this specific embodiment, the honeycomb structure shell 19 is a regular hexagon, the side walls of the honeycomb structure shell 19 are 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 SLA process.

[0045] The present invention adopts a honeycomb lattice structure as the skeleton of the spine, and fills the interior with electrorheological elastomer to simulate the soft tissue of the biological spine. The bionic joints are also filled with electrorheological elastomers. The motor-gear 14 transmission method is used to achieve joint rotation and stiffness adjustment, and the rope 9 driving mechanism is used to simulate the ligaments and muscles around the spine.

[0046] The bionic spine is composed of a cross-connected series of lattice rheological intelligent structure modules 8 and rotational variable stiffness joint modules 6. Four PE ropes 9 are taken (PE material can reduce the friction between the rope and the hole, and has the property of being non-conductive). One end of the rope 9 is fixed to the first joint, and then passes through the rope holes on the joints in turn. Every time a joint is passed through, a spring 5 is placed between the rope 9 and the joint to play a supporting, buffering and shock absorbing role. The entire spine structure is fixed to the bottom bracket 4. The stepper motor is installed on the bottom bracket 4, and the end of the rope 9 is fixed on the rotating drum 1. The rotation of the stepper motor is used to control the retraction and release of the rope 9, thereby controlling the bending movement of the entire bionic spine.

[0047] Electrorheological materials are a new type of material that can change its properties under an external electric field. The shear storage modulus and compression modulus 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 milliseconds.

[0048] The lattice rheological intelligent structure 8 is composed of a honeycomb lattice structure, an electrorheological elastomer, and a flexible electrode 21. The honeycomb lattice structure is printed by the SLA process, and then the flexible electrode 21 is alternately stacked with the cut electrorheological elastomer to ensure that the electrode 17 of each layer fits tightly with the elastomer. At the same time, it should be noted that the electrodes 17 at both ends of each piece of elastomer cannot be connected to the same level of the power supply to prevent short circuit. Therefore, the electrodes 17 are connected to the power supply in the order of "positive-negative-positive-..." to ensure that the electrorheological elastomer can change its stiffness and damping characteristics under the action of voltage, thereby realizing the stiffness adjustment of the bionic rheological intelligent structure. The wire connected to the same end of the power supply is placed on the same side of the structure and passes through the holes of the honeycomb lattice mechanism to facilitate the subsequent application of voltage.

[0049] The honeycomb lattice structure is made of rubber material and has insulation properties. The curved beam structure is used as the side wall of the lattice structure to give it a high load-bearing capacity. The SLA technology is used to carry out the molding process of the lattice structure. The liquid photosensitive resin is first irradiated with ultraviolet light of a specific wavelength and intensity, so that a polymerization reaction occurs and the layer-by-layer solidification is generated to form a three-dimensional honeycomb lattice structure entity.

[0050] The rotational 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 rotating motor 7, a gear 14, an electrorheological elastomer, an electrode 17, etc. A cross bearing is used as a connecting joint of the lattice rheological structure, which can effectively support the bending movement of the spinal structure in four directions, provide the flexibility and stability required for the bionic spine, and maintain 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 plate, and the joint connecting frame 11 and the upper support plate are connected by the universal joint cross bearing 12. The joint connecting frame 11 is assembled with the joint support chassis 10 through bearings. The joint connecting frame 11 has gear teeth that mesh with the gear 14 on the motor driving shaft, and the gear 14 is driven to rotate by the motor, thereby controlling the rotation of the joint. Electrorheological elastomers are filled between the joint connecting frame 11 and the supporting chassis. Two elastomers are installed in each grid. Electrodes 17 are arranged between the elastomers. The stiffness of the electrorheological elastomers is changed by applying voltage, thereby achieving variable stiffness control of joint rotation.

[0051] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A bionic spine variable stiffness device based on electrorheological elastomer, Features: It 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 in plurality and are alternately arranged at intervals on the top of the bracket, the rotationally variable stiffness joint is arranged on the top of the joint supporting chassis, the lattice rheological intelligent structure is arranged on the top of the joint upper supporting plate, the joint supporting chassis and the joint upper supporting plate are provided with opposite through holes on their peripheries, 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 rope between the joint supporting chassis and the joint upper supporting plate is sleeved with the spring; The rotational variable stiffness joint comprises a rotating motor, a joint connecting frame, a universal joint cross bearing, a cross bearing support frame, an electrorheological elastomer and an electrode; 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 rotating 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 the electrode are arranged between the joint connecting frame and the joint support chassis, and the electrode is wrapped around both sides of the electrorheological elastomer, and the stiffness change of the electrorheological elastomer is achieved 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 are alternately stacked in the honeycomb structure shell, and the stiffness of the electrorheological elastomer is changed by applying voltage, thereby realizing the compression stiffness change of the bionic spine.

2. The bionic spine variable stiffness device based on electrorheological elastomer according to claim 1, Features: 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 bionic spine variable stiffness device based on electrorheological elastomer according to claim 2, Features: 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, and the four rope drive motors are installed on the side wall of the bracket.

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

5. The bionic spine variable stiffness device based on electrorheological elastomer according to claim 1, Features: The cross bearing support frame is connected to the joint connecting frame through a pin.

6. The bionic spine variable stiffness device based on electrorheological elastomer according to claim 1, Features: A protruding fan-shaped block is arranged on the top of the joint supporting chassis, and the fan-shaped block is used to separate an installation space for placing the electrorheological elastomer between the joint supporting chassis and the joint connecting frame.

7. The bionic spine variable stiffness device based on electrorheological elastomer according to claim 1, Features: A top cover is arranged on the top of the honeycomb structure shell, and a card slot matching with the card block on the top of the honeycomb structure shell is arranged on the top cover.

8. The bionic spine variable stiffness device based on electrorheological elastomer according to claim 1, Features: The copper wire is fixed on the flexible electrode by means of a conductive copper foil tape, and the flexible electrode is electrified.

9. The bionic spine variable stiffness device based on electrorheological elastomer according to claim 1, Features: 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 SLA process.

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