Soft robotic arm based on light-induced phase transition

Abstract

The application discloses a soft robot arm based on light-induced phase change. The soft robot arm comprises a flexible arm and a manipulator claw, the flexible arm comprises a plurality of modules, each module comprises four groups of driving devices, the driving device comprises four first wrinkle actuators which are distributed in X shape, the top and bottom of the driving device are provided with end covers, and two adjacent end covers are connected through a second wrinkle actuator; the top of the flexible arm is provided with a solar panel, and the manipulator claw is connected with the solar panel through a wire; the wrinkle actuator comprises a wrinkle shell, a low-temperature phase change liquid is arranged in the wrinkle shell, two air bags are arranged in the low-temperature phase change liquid, water and condensation beads are arranged in the air bags, and sodium hydroxide and ammonium chloride are respectively arranged in the condensation beads of the two air bags. The soft robot arm overcomes the dependence on traditional motors, realizes untethered driving, realizes active refrigeration in the gas-liquid phase change, significantly shortens the actuating period, removes the posture condition limitation of heating on the machine, and realizes the coordinated movement of multiple deformation types such as stretching, bending, twisting and variable diameter of multiple degrees of freedom.

Description

Technical Field

[0001] This invention relates to the field of soft robotics, and in particular to a soft robotic arm based on photoinduced phase transition. Background Technology

[0002] Soft robots are a class of robots inspired by biological structures such as snakes, elephant trunks, and octopus tentacles. They possess continuous, elastic structures, enabling them to achieve virtually unlimited degrees of freedom and continuous bending. These characteristics make soft robots suitable for many fields where traditional rigid robots are inapplicable, such as nuclear reactor maintenance, search and rescue, space exploration, and manipulation. However, soft robots face theoretical and technical challenges in their design and fabrication, especially when used in unstructured environments.

[0003] While numerous studies have been conducted on biomimetic soft robots in recent years, challenges remain, including complex manufacturing processes, the inability to achieve bending and twisting in arbitrary directions, the inability to achieve coordinated multi-degree-of-freedom movements such as diameter changes, limited types of deformation, insufficient development of torsional motion, and reliance on traditional servo motors. Achieving high flexibility, high adaptability, and multi-degree-of-freedom deformation in soft robots remains a challenge in current research.

[0004] Most existing soft robots are pneumatic, and the numerous external devices such as air pipes and pumps make the machines bulky and difficult to maintain. Soft robots based on gas-liquid phase change (GLC) are clearly more promising. They possess the same advantages as pneumatic robots, capable of outputting large torques and responding quickly, while avoiding complex external air pumps and pipes, making miniaturization of the drive system possible. However, current research on GLC mainly focuses on the heating phase, with very little research on the cooling and recovery phase. Existing GLC cooling largely relies on natural convection of air or water, lacking active cooling devices, resulting in a significantly longer cooling phase than the heating phase. This leads to a significantly longer phase change cycle for the robot. How to achieve active cooling for robots and shorten the automatic cycle time is an urgent problem to be solved.

[0005] Meanwhile, most existing gas-liquid phase change reactors use either electric heating elements or electromagnetic heating, both of which have significant drawbacks. The electric heating element must be in direct contact with the phase change liquid; otherwise, dry burning is highly likely. This forces gas-liquid phase change driven robots to operate only in specific postures to ensure sufficient contact between the liquid and the heating element. Using a magnetic field as the means of transmitting wireless power to the heater in the liquid requires a pair of receiver and transmitter coils installed inside and outside the container, thus limiting the geometry and actuator size. Furthermore, since heat transfer from the heater to the liquid occurs only locally, the heater must be properly immersed in the liquid regardless of the actuator's posture.

[0006] There are also methods that use lasers to directly heat phase change materials, which often means that the laser energy density is very high to reach the temperature required for the phase change. Due to the lag in temperature rise, this often means that the laser needs to operate continuously for a long period of time. This implies a risk to the eyes of production personnel who manipulate the laser emission and aiming. How to achieve instantaneous photoinduced phase change is a research direction worthy of attention.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a soft robotic arm based on photoinduced phase change. This soft robotic arm can overcome the dependence on traditional motors, achieve untethered drive, realize active cooling in gas-liquid phase change, significantly shorten the actuation cycle, remove the restrictions of heating on the machine's posture conditions, and realize multi-degree-of-freedom coordinated motion of multiple deformation types such as extension, bending, torsion and diameter change.

[0009] This invention provides a soft robotic arm based on light-induced phase transition, comprising a flexible arm and a manipulator. The flexible arm includes several connected modules, each module comprising four sets of drive devices. Each drive device includes four first pleated actuators arranged in an X-shape. End caps are provided at the top and bottom of each drive device, and adjacent end caps are connected via second pleated actuators. The end caps of adjacent modules are fixedly connected. A solar panel is provided on the top of the four end caps of the uppermost module. The bottom of the flexible arm is fixedly connected to the manipulator, and the manipulator is connected to the solar panel via wires.

[0010] The first and second pleated actuators have the same structure, including a pleated shell. The pleated shell contains a low-temperature phase change liquid. The low-temperature phase change liquid contains a first air bladder and a second air bladder. Both the first and second air bladders contain water and several condensation beads. The condensation beads in the first air bladder contain sodium hydroxide crystals, and the condensation beads in the second air bladder contain ammonium chloride crystals.

[0011] Furthermore, in the driving device, the first pleated actuator located at the upper left is connected in series with the first pleated actuator located at the lower right, and the first pleated actuator located at the upper right is connected in series with the first pleated actuator located at the lower left.

[0012] Furthermore, the series connection is made of rubber hose.

[0013] Furthermore, the pleated outer shell is made of a transparent material, the airbag is made of transparent plastic, and the first and second condensate beads are made of polyethylene.

[0014] Furthermore, the manipulator includes a fixed base, and three clamping parts are evenly distributed on the bottom of the fixed base. Each clamping part includes a polytetrafluoroethylene film, and a semiconductor cooling chip and a flexible actuator are fixed on both sides of the polytetrafluoroethylene film, respectively. The semiconductor cooling chip is connected to the four solar panels respectively through wires.

[0015] Furthermore, the flexible actuator comprises, from the inside out, a low-temperature phase change liquid-graphene hydrogel composite material, a composite superelastic, and a fluorine-containing electronic coating.

[0016] Furthermore, the preparation process of the composite superelastic is as follows: after stirring polybutadiene rubber, nano-graphene, and polydimethylsiloxane evenly, a hollow cavity structure is formed by using a paraffin injection molding process.

[0017] Furthermore, the pleated outer shell has cylindrical openings at both ends, the end cap has mounting holes, the cylindrical openings are located in the mounting holes, and a sealing element is provided at the cylindrical openings.

[0018] Furthermore, both the end cap and the seal are made of polylactic acid material.

[0019] In summary, compared with the prior art, the present invention has the following advantages:

[0020] The technical solution of the present invention sets up several modules in series, which can be flexible and varied in movement. Each module includes four driving devices distributed in different directions. Each driving device includes four first pleating actuators distributed in an X shape. The vertical displacement difference realizes the bending and elongation degrees of freedom of the flexible arm. The horizontal displacement difference generates torsion and realizes the vertical rotational degree of freedom. At the same time, a second pleating device is set between the end caps on two adjacent driving devices to realize the variable diameter movement of the flexible arm.

[0021] The first and second wrinkle actuators of this invention use laser irradiation to rupture the condensed beads, causing the internal chemical substances to dissolve rapidly in water. When ammonium chloride dissolves in water, it needs to absorb heat to break the bond between ammonium ions and water molecules, thus absorbing a large amount of heat for cooling. When sodium hydroxide dissolves in water, it forms a sodium hydroxide solution and hydrated hydrogen ions, requiring the release of heat to form new chemical bonds, thus releasing a large amount of heat. This achieves heating and cooling of the low-temperature phase change liquid. The vaporization and liquefaction of the low-temperature phase change liquid alters the gas pressure inside the wrinkle actuator, ultimately achieving length changes in the wrinkle actuator. Laser actuation enables untethered actuation of this soft robot, and chemical reaction cooling allows for rapid cooling within the actuator, shortening the actuation cycle. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the soft robotic arm in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the module structure in an embodiment of the present invention;

[0025] Figure 3 This is the main view of the module in an embodiment of the present invention;

[0026] Figure 4 This is a side view of a module in an embodiment of the present invention;

[0027] Figure 5 This is a top view of the module in an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the end cap structure in an embodiment of the present invention;

[0029] Figure 7 This is a schematic diagram of the structure of the first folding actuator in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the internal structure of the first pleated actuator in an embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the manipulator claw in an embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram of the gripping part of the manipulator claw in an embodiment of the present invention;

[0033] Figure 11 This is a truncated perspective view of the flexible actuator in an embodiment of the present invention;

[0034] Figure 12 This is a schematic diagram of the module rotating to the lower right in an embodiment of the present invention;

[0035] Figure 13 This is a schematic diagram of the module rotating to the right in an embodiment of the present invention;

[0036] Figure 14 This is a schematic diagram illustrating the simultaneous twisting and elongation of the module in an embodiment of the present invention;

[0037] Figure 15This is a schematic diagram of the four-degree-of-freedom motion of the module in an embodiment of the present invention;

[0038] Figure 16 This is a schematic diagram of the module's variable diameter movement in an embodiment of the present invention;

[0039] Figure 17 This contains relevant technical data and information regarding the low-temperature phase change liquid used in this invention.

[0040] Explanation of reference numerals in the attached drawings: 1-Flexible arm, 2-Manipulating claw, 201-Fixed seat, 202-Clamping part, 203-Polytetrafluoroethylene film, 204-Semiconductor cooling chip, 205-Flexible actuator, 2051-Phase change liquid-graphene hydrogel composite material, 2052-Composite superelastic, 2053-Fluorine-containing electronic coating, 3-Module, 4-Drive device, 5-First pleated actuator, 501-Pleated shell, 502-First airbag, 503-Second airbag, 504-Delta bead, 505-Seal, 6-End cap, 601-Mounting hole, 602-Fixing hole, 7-Second pleated actuator, 8-Rubber hose, 9-Solar panel, 10-Wire, 11-Connecting rod. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Example

[0045] A soft robotic arm based on photoinduced phase transition, such as Figure 1 As shown, it includes a flexible arm 1 and a manipulator 2.

[0046] The flexible arm 1 includes several modules 3, such as Figure 2 , Figure 3 , Figure 4 ,and Figure 5 As shown, each module 3 includes four sets of drive devices 4. Each drive device 4 includes four first pleated actuators 5 arranged in an X-shape. The first pleated actuator 5 located at the upper left and the first pleated actuator 5 located at the lower right are connected in series to form one set; the first pleated actuator 5 located at the upper right and the first pleated actuator 5 located at the lower left are connected in series to form another set; and the two sets are not connected to each other. The series connection is made using rubber hoses 8.

[0047] The drive unit 4 is provided with end caps 6 at the top and bottom. Two adjacent end caps 6 are connected by a second pleated actuator 7. The end caps 6 of two adjacent modules 3 are fixedly connected.

[0048] The first pleated actuator 5 and the second pleated actuator 7 have the same structure, except that the second pleated actuator 7 is smaller than the first pleated actuator 5. Figure 7 and Figure 8As shown, the corrugated shell 501, made of transparent polybutadiene rubber, features good flexibility, long service life, good chemical stability, good connection strength, low fluid resistance, good resistance to low-temperature brittleness, good wear resistance, strong compressive strength, and long service life. The corrugated shell 501 contains a low-temperature phase change liquid, which can alter the internal gas pressure of the actuator, causing its length to change. This is particularly suitable for scenarios where gas pressure is converted into displacement or force. In this embodiment, the low-temperature phase change liquid is EnaSolv PF-48 Cleaning Agent (Shanghai Richem International Co., Ltd.), and its related technical data is as follows... Figure 17 As shown.

[0049] A first air bladder 502 and a second air bladder 503, made of transparent plastic, are placed in a low-temperature phase change liquid. Both air bladders 502 and 503 contain water and several polyethylene beads 504. The beads 504 in the first air bladder 502 contain sodium hydroxide crystals, while the beads 504 in the second air bladder 503 contain ammonium chloride crystals. For easy identification and heat absorption, the beads containing ammonium chloride crystals are red, and the beads containing sodium hydroxide crystals are green.

[0050] The condensed beads 504 are ruptured by instantaneous laser irradiation, causing the internal chemical substances to dissolve rapidly in water. When ammonium chloride crystals dissolve in water, they absorb heat to break the bond between ammonium ions and water molecules, thus absorbing a large amount of heat for cooling. When sodium hydroxide crystals dissolve in water, forming sodium hydroxide solution and hydrated hydrogen ions, they release heat to form new chemical bonds, thus releasing a large amount of heat. This achieves heating and cooling of the low-temperature phase change liquid. The vaporization and liquefaction of the low-temperature phase change liquid alters the gas pressure inside the pleated actuator, ultimately achieving the length change of the pleated actuator. Laser drive enables the soft robotic arm to achieve untethered operation, and chemical reaction cooling rapidly cools the actuator, shortening the actuation cycle. In this embodiment, a variable power and variable focal length laser emitter with a power of 10-20W is used. During irradiation, it is generally necessary to ensure that the laser spot hitting the condensed beads is small enough to maintain energy concentration; the spot size should be within 5mm.

[0051] like Figure 6 As shown, the top two ends of the end cap 6 have mounting holes 601 for mounting the first pleated actuator 5; the left and right ends of the end cap 6 also have mounting holes 601 for mounting the second pleated actuator 7; the middle of the end cap 6 has a fixing hole 602 for connecting with the adjacent module 3 by screws and nuts.

[0052] Both ends of the corrugated housing 501 are designed with cylindrical openings. The mounting hole 601 on the end cap 6 has a smaller diameter than the cylindrical opening, which is used for interference fit to increase sealing.

[0053] A cylindrical opening connects to the mounting hole 601 of the end cap 6. A cylindrical seal 505 is installed on the inner wall of the cylindrical opening. The diameter of the seal 505 is slightly larger than the diameter of the cylindrical opening to achieve an interference fit and maximize its sealing performance. Both the end cap 6 and the seal 505 are made of polylactic acid material by 3D printing.

[0054] When the first pleated actuator 5 located at the upper left and the first pleated actuator 5 located at the lower right are connected in series, the corresponding seal 505 is provided with an installation port for easy connection of the rubber hose 8. When the first pleated actuator 5 located at the upper right and the first pleated actuator 5 located at the lower left are connected in series, the corresponding seal 505 is provided with an installation port for easy connection of the rubber hose 8. One end of the seal 505 connecting the first pleated actuator 5 and the second pleated actuator 7 to the end cap 6 is completely closed.

[0055] Solar panels 9 are fixedly installed on the top of the four end caps 6 of the topmost module 3 in the flexible arm 1. Rigid connecting rods 11 are installed in the fixing holes 602 of the four end caps 6 at the bottommost part of the flexible arm 1. The other end of the connecting rods 11 is fixedly connected to the side wall of the fixing seat 201 of the manipulator 2.

[0056] like Figure 9 As shown, the manipulator 2 includes a fixed base 201, and three clamping portions 202 are evenly distributed on the bottom of the fixed base 201. Each clamping portion 202 includes a polytetrafluoroethylene film 203, such as... Figure 10 As shown, the polytetrafluoroethylene film 203 has good heat and cold resistance. In this embodiment, a polytetrafluoroethylene film with a thickness of 0.05 mm is used. Three semiconductor cooling chips 204 are fixed on the inner side of the polytetrafluoroethylene film 203, and three flexible actuators 205 are fixed on the outer side. Each semiconductor cooling chip 204 corresponds to one flexible actuator 205. The distance between two adjacent flexible actuators 205 is 5 mm. This distance setting can ensure that the manipulator 2 can form a suitable bending angle when working.

[0057] When direct current is applied in different directions, the thermoelectric cooler 204 can achieve heating and cooling respectively through the Peltier effect. Three thermoelectric coolers 204 are connected in parallel via wire 10 and then connected to four solar panels 9 respectively. Each thermoelectric cooler 204 has a wire connected to a solar panel 9. The corresponding current can heat or cool the thermoelectric cooler 204 respectively. In actual use, ordinary natural sunlight is used to irradiate the corresponding solar panel 9 as needed, causing the thermoelectric cooler 204 to heat or cool, and causing the flexible actuator 205 to deform, thus achieving the gripping and releasing of the clamping part 202. This irradiation of the solar panel 9 does not require high-power lasers; ordinary natural light is sufficient, and it can be irradiated for a long time, ensuring the safety of personnel and improving interactive safety.

[0058] When sunlight shines on two of the four solar panels 9 that generate a heating current on the inner side of the thermoelectric cooler 204, the side of the thermoelectric cooler 204 closest to the flexible actuator 205 begins to heat up. The flexible actuator 205 is heated, causing the phase change material inside to vaporize, resulting in an increase in air pressure and volume. When the three clamping parts 202 come into contact with each other and squeeze, the gripping action of the manipulator 2 is realized.

[0059] When sunlight shines on the other two solar panels 9, the side of the semiconductor cooling chip 204 closest to the flexible actuator 205 begins to cool, causing the internal phase change material to gradually and rapidly liquefy, resulting in a drop in air pressure. Under the rebound force of the composite hyperelastic body 2052, the volume of the flexible actuator 205 will decrease, and the manipulator 2 will gradually release. This method of using the semiconductor cooling chip 204 can greatly accelerate the phase change rate and improve the performance of the manipulator 2.

[0060] The flexible actuator 205 consists of, from the inside out, a phase change liquid-graphene hydrogel composite material 2051, a composite superelastic body 2052, and a fluorine-containing electronic coating 2053.

[0061] The preparation method of phase change liquid-graphene hydrogel composite material 2051 is as follows: low temperature phase change liquid and millimeter-sized graphene hydrogel are thoroughly and uniformly mixed at a volume ratio of 1:1, and injected into the hollow cavity inside the composite superelastic 2052 using a syringe. The graphene hydrogel has a loose porous structure, which can fully adsorb the phase change liquid. At the same time, graphene has excellent thermal and electrical conductivity, which can accelerate the heat conduction process and optimize the driving performance of the manipulator.

[0062] Composite superelastic 2052 is made by uniformly mixing 2g of polybutadiene rubber, 1g of nano-scale graphene, and 3g of polydimethylsiloxane (PDMS) in a mixer, and then using a paraffin injection molding process to create a hollow cavity structure. This structure serves as the primary encapsulating and sealing material, ensuring that the internally sealed phase change material does not escape during the phase change process. Simultaneously, it exhibits good toughness and elasticity, allowing for significant deformation and repeated recovery. Nano-scale graphene is used to improve the thermal conductivity of the composite material.

[0063] The outer layer of the composite superelastic 2052 is coated with a fluorinated electronic protective coating 2053 (3MNovec 1700 is used in this embodiment). After drying, this coating forms a transparent film, which plays a better role in sealing and protection. The film has excellent hydrophobicity and oil resistance. It can resist oil and water, ensuring that the control claw can be used in more complex and variable fields, and ensuring that the internal air pressure will not leak out, thus improving its durability.

[0064] The motion principle of module 3 based on photoinduced phase transition provided by this invention is as follows: Figures 12-16 As shown ( Figures 12-16 The images are all top views of a single module 3, where the upper and lower end covers of the drive device 4 are in the same initial state. Numbers ①-⑧ represent the eight first pleating devices 5 connected to the upper end cover. The specific process is as follows:

[0065] like Figure 12 As shown, when the first pleat actuators 5 (No. ① and No. ⑧) extend synchronously, the drive device 4 will be subjected to the extension shown by the solid line diagonally in the figure. This extension has a horizontal component in the XY horizontal plane and a vertical component in the Z-axis direction. At this time, the horizontal force cancels each other out, leaving only the vertical force, which causes the module 3 to rotate to the lower right.

[0066] like Figure 13 As shown, when the first folding actuators 5 (6 and 7) extend synchronously, module 3 rotates to the right. By combining them, a two-degree-of-freedom bending motion can be achieved.

[0067] like Figure 14 As shown, when the first folding actuators 5, numbered ②, ④, ⑥ and ⑧, extend synchronously, the horizontal forces superimposed cause module 3 to simultaneously achieve torsion and extension.

[0068] like Figure 15 As shown, when all the first pleats 5 extend synchronously, module 3 extends, achieving four degrees of freedom of motion.

[0069] like Figure 16 As shown, when the second pleating device 7 extends / contracts synchronously, the soft robotic arm achieves a variable diameter movement.

[0070] This invention proposes a soft robotic arm based on photoinduced phase transition. Inspired by folded actuators and the kinematic characteristics of an elephant's trunk, and through detailed analysis of the trunk's motion mechanism and degree-of-freedom distribution, the flexible arm is simplified into several modules. Each module has four sets of X-shaped drive devices arranged in four two-dimensional directions. Each module has four degrees of freedom: rotation in two directions, axial extension and contraction, and circumferential torsion. In addition, each module has eight laterally placed small second folded actuators at its end cap, enabling variable-diameter movement of the flexible arm. More modules can be connected in series as needed to complete the required tasks, offering flexible and versatile motion modes.

[0071] This invention proposes a pleated actuator based on gas-liquid phase change drive. It achieves rapid heating and cooling by inducing a controlled chemical reaction using laser light, causing the internal phase change material to rapidly vaporize and liquefy, resulting in changes in internal pressure that extend and retract the actuator. Chemically driven active cooling exhibits a faster cooling rate than natural convection cooling. Due to this effective active cooling function, each actuation cycle is shortened, significantly reducing response time. Furthermore, due to gravity, the cooling and heating chemicals remain immersed in the phase change liquid as the robot's posture changes. This technology frees chemical actuation from the limitations of machine spatial posture, enabling the robot to perform more complex and diverse movements.

[0072] This laser-induced phase transition multi-degree-of-freedom flexible arm uses the laser only as the induction condition, with an extremely short operating time, increasing the equipment's safety factor, reducing energy consumption, and achieving untethered drive, eliminating the need for complex external pneumatic equipment. Each module has four degrees of freedom and variable diameter capability, strong load capacity, fast response speed, light weight, simple structure, low control system complexity, and short actuation cycle.

[0073] The structure, made of flexible materials and rigid fasteners, achieves a rigid-flexible coupling, combining the advantages of both rigidity and flexibility. It has strong adaptability, a large working space, safer interaction with humans, and can withstand impact forces.

[0074] This invention also proposes a flexible manipulator based on gas-liquid phase change composite material, which achieves untethered drive through optical drive, simplifying the structure of the machine.

[0075] The soft robotic arm based on light-induced phase change provided by this invention simplifies the structure and manufacturing process of soft robots, realizes coordinated motion of multiple degrees of freedom, including extension, bending, torsion and diameter change, overcomes dependence on traditional motors, realizes tetherless drive, achieves active cooling in gas-liquid phase change, significantly shortens the actuation cycle, and removes the restrictions of heating on the posture conditions of the machine.

[0076] 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 soft robotic arm based on photoinduced phase transition, characterized in that, The device includes a flexible arm (1) and a manipulator (2). The flexible arm (1) includes several connected modules (3). Each module (3) includes four sets of drive devices (4). Each drive device (4) includes four first pleated actuators (5) arranged in an X-shape. The top and bottom of each drive device (4) are provided with end caps (6). Two adjacent end caps (6) are connected by second pleated actuators (7). The end caps (6) of two adjacent modules (3) are fixedly connected. The top of the four end caps (6) of the uppermost module (3) is provided with a solar panel (9). The bottom of the flexible arm (1) is fixedly connected to the manipulator (2). The manipulator (2) is connected to the solar panel (9) through a wire (10). The first pleated actuator (5) and the second pleated actuator (7) have the same structure, including a pleated shell (501). The pleated shell (501) contains a low-temperature phase change liquid. The low-temperature phase change liquid contains a first air bladder (502) and a second air bladder (503). The first air bladder (502) and the second air bladder (503) each contain water and several condensation beads (504). The condensation beads (504) of the first air bladder (502) contain sodium hydroxide crystals, and the condensation beads (504) of the second air bladder (503) contain ammonium chloride crystals. The beads (504) are ruptured by instantaneous laser irradiation, and the internal chemicals dissolve rapidly in the water.

2. The soft robotic arm according to claim 1, characterized in that, In the drive device (4), the first pleated actuator (5) located at the upper left is connected in series with the first pleated actuator (5) located at the lower right, and the first pleated actuator (5) located at the upper right is connected in series with the first pleated actuator (5) located at the lower left.

3. The soft robotic arm according to claim 2, characterized in that, The series connection uses a rubber hose (8).

4. The soft robotic arm according to claim 1, characterized in that, The pleated outer shell (501) is made of transparent material, the first airbag (502) and the second airbag (503) are made of transparent plastic, and the condensate beads (504) are made of polyethylene.

5. The soft robotic arm according to claim 1, characterized in that, The manipulator (2) includes a fixed base (201), and three clamping parts (202) are evenly distributed on the bottom of the fixed base (201). Each clamping part (202) includes a polytetrafluoroethylene film (203), and a semiconductor cooling chip (204) and a flexible actuator (205) are fixed on both sides of the polytetrafluoroethylene film (203). The semiconductor cooling chip (204) is connected to the four solar panels (9) through wires.

6. The soft robotic arm according to claim 5, characterized in that, The flexible actuator (205) comprises, from the inside out, a low-temperature phase change liquid-graphene hydrogel composite material (2051), a composite superelastic (2052), and a fluorine-containing electronic coating (2053).

7. The soft robotic arm according to claim 6, characterized in that, The preparation process of the composite superelastic (2052) is as follows: after stirring polybutadiene rubber, nano-graphene and polydimethylsiloxane evenly, a hollow cavity structure is made by using paraffin injection molding process.

8. The soft robotic arm according to claim 1, characterized in that, The pleated outer shell (501) has cylindrical openings at both ends, and the end cap (6) has mounting holes (601). The cylindrical openings are located in the mounting holes (601), and the cylindrical openings are provided with sealing elements (505).

9. The soft robotic arm according to claim 8, characterized in that, Both the end cap (6) and the seal (505) are made of polylactic acid material.

Images