Logarithmic spiral bidirectional bending pneumatic soft actuator and soft robot

Abstract

The invention relates to the technical field of soft body robots, in particular to a logarithmic spiral bidirectional bending pneumatic soft body actuator and a soft body robot, the bidirectional bending pneumatic soft body actuator comprises an elastic body and a deformation limiting layer, the elastic body comprises an air hole structure, a fixing structure and a deformation structure which are connected in sequence; the interiors of the air hole structure, the fixing structure and the deformation structure are communicated to form an air channel structure; the air hole structure is communicated with an external air source, and the deformation structure is in a logarithmic spiral shape initially; and the deformation limiting layer is adhered to one side of the maximum outer cambered surface of the deformation structure and is used for limiting the deformation of one side, adhered by the deformation limiting layer, of the elastic body. A deformation structure in the bidirectional bending pneumatic soft body actuator adopts biological bionic design and is in a logarithmic spiral shape, and the bidirectional bending pneumatic soft body actuator has bidirectional bending capacity, high flexibility and better adaptability to a target object.

Description

Technical Field

[0001] The present invention relates to the technical field of soft robots, and particularly relates to a logarithmic spiral bidirectional bending pneumatic soft actuator and a soft robot. Background Art

[0002] A pneumatic soft robot is a soft robot driven by gas. Due to its advantages such as large deformation, low cost, and light weight, it has become a widely popular soft robot. In past research, soft robots made based on pneumatic soft actuators have been applied in fields such as agriculture, medical rehabilitation, and noise control. By designing different structures, pneumatic soft actuators can achieve functions including bending, elongation, torsion, and contraction. However, the bending angle of a traditional simple pneumatic bending actuator is often determined by the air pressure in its only internal air duct, which means that this actuator can only achieve a single movement. If multi-directional bending is required, it often needs to be designed as a structure with multiple parallel air chambers. This increases the complexity of the design, manufacturing, and driving of the soft actuator to a certain extent. Summary of the Invention

[0003] The present invention provides a logarithmic spiral bidirectional bending pneumatic soft actuator and a soft robot to solve the technical problems mentioned in the background art.

[0004] To achieve the above object, the technical solution of the present invention is realized as follows: The present invention provides a logarithmic spiral bidirectional bending pneumatic soft actuator, including: An elastomer, including a pore structure, a fixed structure, and a deformation structure connected in sequence; the pore structure, the fixed structure, and the deformation structure are internally connected to form an air duct structure; the pore structure is communicated with an external air source, and the deformation structure is in a logarithmic spiral shape initially; A deformation limiting layer, bonded to one side of the maximum outer arc surface of the deformation structure, for limiting the deformation amount of the side of the elastomer bonded by the deformation limiting layer.

[0005] Further, a plurality of partition plates are distributed at intervals on the side of the air duct structure away from the deformation limiting layer to limit the bending direction of the bidirectional bending pneumatic soft actuator.

[0006] Further, a plurality of limiting holes are provided on the fixed structure.

[0007] Further, the logarithmic spiral is a spiral curve presented in a polar coordinate system, and the distance from each point on the spiral curve to the origin O is proportional to the logarithm of the current angle where the current angle represents the polar angle of the current point relative to the origin O; the polar coordinate equation of the spiral curve is expressed as: ; Among them, represents the distance from the current point to the origin O; is a constant representing the starting radius; is another constant used to control the tightness of the helix; represents the natural constant.

[0008] This equation describes how the radius changes exponentially as the angle increases.

[0009] Furthermore, the vertical section of the deformation structure gradually becomes smaller from the side connected to the fixed structure to the side away from the fixed structure.

[0010] Furthermore, a plurality of grooves distributed along the length direction of the elastomer are provided on the outer side of the deformation limiting layer and / or on the side of the elastomer away from the deformation limiting layer; Or, a plurality of protrusions distributed along the length direction of the elastomer are formed on the outer side of the deformation limiting layer and / or on the side of the elastomer away from the deformation limiting layer.

[0011] On the other hand, the present invention also provides a soft robot, including a bidirectional bending pneumatic soft actuator and an independent air source system communicated with the bidirectional bending pneumatic soft actuator; The independent air source system includes an air compressor, a triple unit, a pressure regulating valve, and a solenoid valve connected in sequence, and the solenoid valve is communicated with the bidirectional bending pneumatic soft actuator.

[0012] Furthermore, the number of the bidirectional bending pneumatic soft actuators is one or more.

[0013] Furthermore, the triple unit includes an air filter, a pressure reducing valve, and an oiler connected in sequence, wherein the air filter is communicated with the air compressor, the oiler is communicated with the pressure regulating valve, and a pressure gauge is arranged on the pressure reducing valve.

[0014] Advantages of the present invention: 1. The present invention discloses a logarithmic spiral bidirectional bending pneumatic soft actuator. By controlling a single air source, bidirectional bending of the deformation structure can be achieved, which has higher flexibility and better adaptability to the target compared with traditional pneumatic soft actuators.

[0015] 2. The deformation structure on the elastomer in the present invention adopts a bio - bionic design, that is, the deformation structure is in the form of a logarithmic spiral commonly found in nature in the initial state. Compared with traditional pneumatic soft actuators, it occupies less space and is convenient for storage and transportation.

[0016] 3. Compared with the deformation structure in the form of an Archimedean spiral, the tail of the deformation structure in the form of a logarithmic spiral (i.e., the side of the deformation structure far from the fixed structure) is more flexible, which can further improve the adaptability of the deformation structure to the target object.

[0017] 4. The present invention also optimizes the air passage structure on the double-bending pneumatic soft actuator, and arranges multiple partition plates inside the air passage structure. This partition plate structure can limit the deformation of the deformation structure in directions other than double-bending, optimize the bending effect of the double-bending pneumatic soft actuator, and is beneficial to the unwinding and reverse bending of the double-bending pneumatic soft actuator. Brief Description of the Drawings

[0018] Figure 1 is a three-dimensional structure schematic diagram of the double-bending pneumatic soft actuator in the present invention; Figure 2 is a cross-sectional structure schematic diagram of the double-bending pneumatic soft actuator in the present invention; Figure 3 is a deformation schematic diagram of the deformation structure and the deformation limiting layer in the present invention; Figure 4 is a scaled structure diagram of the independent air source system in the present invention; Figure 5 is the internal angle marking schematic diagram in the present invention; Figure 6 is a schematic diagram of two spiral deformation structures mentioned in the present invention, wherein Figure (a) is a schematic diagram of the deformation structure in the form of a logarithmic spiral, and Figure (b) is a schematic diagram of the deformation structure in the form of an Archimedean spiral.

[0019] Description of the Reference Numerals: 1. Elastomer; 11. Pore structure; 12. Fixed structure; 121. Limit hole; 13. Deformation structure; 14. Air passage structure; 15. Partition plate; 2. Deformation limiting layer; 3. Air compressor; 4. FRL unit; 41. Air filter; 42. Pressure reducing valve; 43. Pressure gauge; 44. Lubricator; 5. Pressure regulating valve; 6. Solenoid valve. Detailed Embodiments

[0020] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0021] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0022] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0024] It should also be noted that in the embodiments of the present application, the same reference numerals are used to denote the same components or the same parts. For the same parts in the embodiments of the present application, only one of the parts or components may be marked with a reference numeral in the drawings. It should be understood that the reference numerals are also applicable to other identical parts or components.

[0025] Referring to Figure 1 and Figure 2 , the embodiments of the present application provide a logarithmic spiral bidirectional bending pneumatic soft actuator, including: Elastomer 1, including a pore structure 11, a fixing structure 12 and a deformation structure 13 connected in sequence; the pore structure 11, the fixing structure 12 and the deformation structure 13 are internally connected to form an airway structure 14; the pore structure 11 is in communication with an external air source, and the deformation structure 13 is in a logarithmic spiral shape initially; Deformation limiting layer 2, bonded to one side of the maximum outer arc surface of the deformation structure 13, for limiting the deformation amount of the side of the elastomer 1 bonded by the deformation limiting layer 2. Structurally, an installation groove can be opened on one side of the maximum outer arc surface of the deformation structure 13, and the deformation limiting layer 2 is bonded and fixed in the installation groove, or the deformation limiting layer 2 is directly bonded to one side of the maximum outer arc surface of the deformation structure 13 by using glue or the like.

[0026] The present invention discloses a logarithmic spiral bidirectional bending pneumatic soft actuator, which can realize bidirectional bending of a deformable structure 13 by controlling a single air source. Compared with traditional pneumatic soft actuators, it has higher flexibility.

[0027] The deformation structure 13 on the elastomer 1 in the present invention adopts a biomimetic design, that is, the deformation structure 13 is in a logarithmic spiral shape commonly seen in nature in the initial state, such as conch shells, seahorse tails, elephant trunks, etc.; compared with traditional pneumatic soft actuators, it occupies less space and is convenient for storage and transportation.

[0028] In some embodiments, the elastic body 1 is made of elastic material, including but not limited to silicone.

[0029] In some embodiments, a plurality of partitions 15 are spaced apart on one side of the airway structure 14 away from the deformation limiting layer 2 to limit the deformation of the deformation structure 13 in directions other than bidirectional bending, optimize the deformation effect of the bidirectional bending pneumatic soft actuator, and facilitate the untwisting and reverse bending of the bidirectional bending pneumatic soft actuator. The material of the partition 15 can be a hard material, such as ABS plastic sheet, etc.; it can also be the same material as the elastic body 1.

[0030] The spacing and direction of the partition 15 structure include but are not limited to the following: Figure 2 shown.

[0031] In some embodiments, reference Figure 1 and Figure 2 The fixing structure 12 is provided with a plurality of limiting holes 121, and the number of the limiting holes 121 is preferably four. In addition, the number and layout of the plurality of limiting holes 121 are not limited to Figure 1 and Figure 2 As shown, other different numbers and layout positions are also possible. The bidirectional bending pneumatic soft actuator is fixed to the external structure through the limiting holes 121 on the fixing structure 12.

[0032] In some embodiments, the logarithmic spiral is a spiral curve presented in a polar coordinate system, and the distance between each point on the spiral curve and the origin O is proportional to the angle at which the current point is located. The logarithm of the current point is proportional to Indicates the polar angle of the current point relative to the origin O; the polar coordinate equation of the spiral curve is expressed as: ; in, Indicates the distance from the current point to the origin O; is a constant representing the starting radius; is another constant that controls the tightness of the spiral; represents the natural constant.

[0033] This polar equation describes how the radius changes exponentially as the angle increases.

[0034] In some embodiments, the vertical cross-section of the deformation structure 13 gradually decreases from the side connected to the fixed structure 12 to the side away from the fixed structure 12. This design can improve the flexibility of the tail of the deformation structure 13 and further improve the adaptability of the bidirectional bending pneumatic soft actuator to the target object.

[0035] In some embodiments, a plurality of grooves are provided on the outer side of the deformation limiting layer 2 and / or on the side of the elastomer 1 away from the deformation limiting layer 2 and distributed along the length direction of the elastomer 1; to increase the friction between the bidirectional bending pneumatic soft actuator and the target object; Alternatively, a plurality of protrusions are formed on the outer side of the deformation limiting layer 2 and / or on the side of the elastomer 1 away from the deformation limiting layer 2 and distributed along the length direction of the elastomer 1; to increase the friction between the bidirectional bending pneumatic soft actuator and the target object.

[0036] The working principle of the bidirectional bending pneumatic soft actuator in the present invention is specifically as follows: a. The bidirectional bending pneumatic soft actuator unwinds and recovers under positive pressure (i.e., forward bending); Reference Figures 1 to 4 , in the initial state, the shape of the deformation structure 13 on the elastomer 1 presents a logarithmic spiral, and the main body of the bidirectional bending pneumatic soft actuator is the deformation structure 13. This is beneficial to reducing the initial size of the bidirectional bending pneumatic soft actuator (abbreviated as actuator). After applying positive pressure through an external air source, the deformation structure 13 on the elastomer 1 expands under pressure. Since the deformation limiting layer 2 is bonded to one side of the largest outer arc surface of the deformation structure 13, restricted by the deformation limiting layer 2, the bidirectional bending pneumatic soft actuator gradually unfolds as the air pressure increases. The unfolding degree of the bidirectional bending pneumatic soft actuator is positively correlated with the air pressure value. Then, by continuously reducing the positive pressure, the unfolding degree of the bidirectional bending pneumatic soft actuator will become smaller and finally return to the initial logarithmic spiral shape. By controlling the positive pressure, the control of the unwinding and recovery of the bidirectional bending pneumatic soft actuator is achieved. This unwinding and recovery phenomenon can be considered as a forward bending phenomenon in which the bending degree is controlled by positive pressure.

[0037] b. The bidirectional bending pneumatic soft actuator bends reversely under positive pressure; Reference Figures 1 to 4, on the basis that the double - bending pneumatic soft actuator is fully expanded under positive pressure drive, continue to increase the pressure inside the deformation structure 13. Since the deformation - limiting layer 2 is bonded to one side of the maximum outer arc surface of the deformation structure 13, restricted by the deformation - limiting layer 2, the double - bending pneumatic soft actuator will bend towards the other side. The degree of bending is related to the positive - pressure value. The greater the pressure value, the greater the reverse - bending degree of the double - bending pneumatic soft actuator. After reducing the positive pressure, the reverse - bending degree of the double - bending pneumatic soft actuator becomes smaller. By controlling the positive pressure, the control of the bending of the double - bending pneumatic soft actuator in the other direction is achieved.

[0038] On the other hand, the present invention also provides a soft robot, including a double - bending pneumatic soft actuator and an independent air - source system communicated with the double - bending pneumatic soft actuator; Refer to Figure 4 , the independent air - source system includes an air compressor 3, a triple unit 4, a pressure regulating valve 5, and a solenoid valve 6 that are connected in sequence, and the solenoid valve 6 is communicated with the double - bending pneumatic soft actuator.

[0039] In some embodiments, the number of the double - bending pneumatic soft actuators is one or more, and multiple double - bending pneumatic soft actuators are arranged in multiple different directions. The layout form can be, but is not limited to, a distribution form similar to the multi - legs of an octopus.

[0040] This structure can improve the adaptability of the soft robot to the target object.

[0041] In some embodiments, the triple unit 4 includes an air filter 41, a pressure reducing valve 42, and an oil - mist lubricator 44 that are connected in sequence. Among them, the air filter 41 is communicated with the air compressor 3, the oil - mist lubricator 44 is communicated with the pressure regulating valve 5, and a pressure gauge 43 is arranged on the pressure reducing valve 42. The oil - mist lubricator 44 is used for air - path lubrication to improve the lubrication performance of the pressure regulating valve 5 and the solenoid valve 6 and extend the service life of the pressure regulating valve 5 and the solenoid valve 6.

[0042] Refer to Figure 6 , Figure 6It includes schematic diagrams of two different spiral deformation structures. Among them, diagram (a) is a schematic diagram of the logarithmic spiral deformation structure 13, and diagram (b) is a schematic diagram of the Archimedean spiral deformation structure. The cross-section of the logarithmic spiral deformation structure 13 changes progressively with the distance from the fixed structure 12. As it gradually moves away from the fixed structure 12 and approaches the free end, the cross-section gradually decreases. As the cross-section gradually decreases, the deformation structure 13 becomes more sensitive to the driving air pressure. The cross-section of the Archimedean spiral deformation structure does not change with the distance from the fixed structure 12. Therefore, compared with the Archimedean spiral deformation structure, the tail of the logarithmic spiral deformation structure 13 (i.e., the side of the deformation structure 13 away from the fixed structure 12) is more flexible, which can improve the adaptability of the bidirectional bending pneumatic soft actuator to the target object.

[0043] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Moreover, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A logarithmic spiral bidirectional bending pneumatic soft actuator, characterized in that: include: The elastic body (1) comprises a pore structure (11), a fixed structure (12) and a deformation structure (13) which are connected in sequence; the pore structure (11), the fixed structure (12) and the deformation structure (13) are internally connected to form an airway structure (14); the pore structure (11) is connected to an external air source, and the deformation structure (13) is initially in a logarithmic spiral shape; The deformation limiting layer (2) is bonded to one side of the maximum outer arc surface of the deformation structure (13) and is used to limit the deformation amount of the side of the elastic body (1) bonded to the deformation limiting layer (2).

2. The logarithmic spiral bidirectional bending pneumatic soft actuator according to claim 1, characterized in that: A plurality of partition plates (15) are spaced apart on a side of the airway structure (14) away from the deformation limiting layer (2) to optimize the bending effect of the bidirectional bending pneumatic soft actuator.

3. The logarithmic spiral bidirectional bending pneumatic soft actuator according to claim 1, characterized in that: The fixing structure (12) is provided with a plurality of limiting holes (121).

4. The logarithmic spiral bidirectional bending pneumatic soft actuator according to claim 1, characterized in that: The logarithmic spiral is a spiral curve presented in a polar coordinate system. The distance between each point on the spiral curve and the origin O is proportional to the angle at which the current point is located. The logarithm of the current point is proportional to Indicates the polar angle of the current point relative to the origin O. The polar coordinate equation of the spiral curve is expressed as: ； in, Indicates the distance from the current point to the origin O; is a constant representing the starting radius; is another constant that controls the tightness of the spiral; Represents a natural constant.

5. The logarithmic spiral bidirectional bending pneumatic soft actuator according to claim 1, characterized in that: The vertical cross-section of the deformation structure (13) gradually decreases from the side connected to the fixed structure (12) to the side facing away from the fixed structure (12).

6. The logarithmic spiral bidirectional bending pneumatic soft actuator according to claim 1, characterized in that: The outer side surface of the deformation limiting layer (2) and / or the side of the elastic body (1) away from the deformation limiting layer (2) is provided with a plurality of grooves distributed along the length direction of the elastic body (1); Alternatively, a plurality of protrusions distributed along the length direction of the elastic body (1) are formed on the outer side surface of the deformation limiting layer (2) and / or on the side of the elastic body (1) away from the deformation limiting layer (2).

7. A soft robot, characterized in that: A bidirectional bending pneumatic soft actuator comprising any one of claims 1 to 6, and an independent air source system connected to the bidirectional bending pneumatic soft actuator; The independent air source system comprises an air compressor (3), a triple joint (4), a pressure regulating valve (5) and a solenoid valve (6) which are connected in sequence, and the solenoid valve (6) is connected to a bidirectional bending pneumatic soft actuator.

8. The soft robot according to claim 7, characterized in that: The number of the bidirectional bending pneumatic soft actuator is one or more.

9. The soft robot according to claim 7, characterized in that: The triple component (4) comprises an air filter (41), a pressure reducing valve (42), and an oil mist collector (44) which are connected in sequence, wherein the air filter (41) is connected to the air compressor (3), the oil mist collector (44) is connected to the pressure regulating valve (5), and a pressure gauge (43) is arranged on the pressure reducing valve (42).

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