An endoskeletal pneumatic soft robot

Abstract

This invention provides an endoskeleton pneumatic soft robot, comprising: a helical pneumatic soft body, two anchoring components, and a pneumatic drive unit connected to the pneumatic soft body. The pneumatic soft body includes a strip-shaped flexible covering structure capsule and a flexible endoskeleton. The flexible endoskeleton is a spring, and the flexible covering structure capsule wraps around the spring's inner cavity along the spring's helical path. The two ends of the flexible covering structure capsule are an open end and a closed end, respectively. The end of the pneumatic soft body near the open end of the flexible covering structure capsule is a fixed end, and the other end of the pneumatic soft body is a free end. The two anchoring components are respectively connected to the fixed end and the free end of the pneumatic soft body. This invention can significantly reduce deformation waiting time, completing structural elongation within seconds, making it suitable for situations requiring rapid deployment. Furthermore, while ensuring deformability, it is smaller and more compact, making it more suitable for space-constrained operating environments.

Description

Technical Field

[0001] This invention relates to an endoskeleton pneumatic soft robot, belonging to the field of robotics. Background Technology

[0002] In recent years, due to the needs of specific scenarios, such as industrial inspection, medical operations and pipeline inspection, there is a need for lighter and more flexible robots, and researchers have focused their research on the field of soft robots.

[0003] Pneumatically driven soft robots have attracted considerable research attention due to their low cost, environmental friendliness, safety, and resistance to equipment damage. These robots can be categorized into three types: First, airbags or pneumatic cavities made primarily of silicone through a casting process. These structures expand upon the injection of external gas, achieving deformation. However, their axial extension is limited, and the radial dimension increases significantly during expansion, restricting their applicability in compact spaces or applications with strict requirements on lateral dimensions. Second, pneumatic bellows structures, which allow for control of internal air pressure. Axial deformation occurs; however, this type of structure has high driving air pressure and low expansion ratio per unit pressure, making it unsuitable for low-pressure or low-flow driving environments. Third, there are membrane-type pneumatic structures, which are multi-cavity pipes made of materials such as PET, origami, or HDPE. They rely on the low stiffness of the membrane to achieve rapid deployment and expansion. This type of structure is lightweight and flexible, making it suitable for fast-response flexible systems. However, due to the lack of internal skeleton support, the structure is not stable enough after expansion and is prone to local collapse or folding. It also lacks self-holding ability and requires continuous internal pressure to maintain its shape. Furthermore, the processing is complex and the manufacturing cost is high.

[0004] In the field of pneumatically driven soft robots, to balance flexible deformation and structural support capabilities, existing technologies include designs that directly embed springs within a flexible covering structure. This type of design provides sealing and deformation space through the flexible covering structure, using the embedded spring as the core support component to attempt to achieve the structure's extension or bending functions. It has been attempted in scenarios such as pipeline inspection and small robotic arms. However, published patent application CN 115157230 A discloses a spring-driven pneumatic soft robot and its fabrication method. Its bulky structure requires a separate chamber and redundant space to accommodate the spring's extension and retraction, resulting in an overall large size that is unsuitable for confined space operations such as pipeline inspection and precision equipment internal maintenance. The published patent application CN202210692204.0 discloses a bionic quadruped mobile robot based on a folded spring tube soft robotic arm. However, its deformation performance and response speed are insufficient, the fit between the spring and the covering structure is poor, it is easy to have asynchronous deformation, the extension range is limited, and when pneumatically driven, the redundant space of the chamber needs to be filled first, and it takes a long time to complete the maximum elongation deformation, which cannot meet the needs of rapid deployment. Summary of the Invention

[0005] The purpose of this invention is to provide an endoskeleton pneumatic soft robot to solve the problems existing in the prior art.

[0006] To address the aforementioned technical problems, this invention provides an endoskeleton pneumatic soft robot, comprising: a helical pneumatic soft body, two anchoring components, and a pneumatic drive unit connected to the pneumatic soft body. The pneumatic soft body includes a strip-shaped flexible covering structure capsule and a flexible endoskeleton. The flexible endoskeleton is a spring. The two ends of the flexible covering structure capsule are an open end and a closed end, respectively. One end of the pneumatic soft body near the open end of the flexible covering structure capsule is a fixed end, and the other end of the pneumatic soft body is a free end. The two anchoring components are respectively connected to the fixed end and the free end of the pneumatic soft body. The flexible covering structure capsule wraps the spring around its inner cavity along the helical path of the spring, and the end of the open end of the flexible covering structure capsule is fixedly connected to the corresponding position of the spring. The open end of the flexible covering structure capsule is connected to the pneumatic drive unit, sealing the connection between the open end of the flexible covering structure capsule and the pneumatic drive unit.

[0007] In one specific embodiment, the two anchoring components are respectively disposed at the bottom of the fixed end and the bottom of the free end of the pneumatic soft body, and the anchoring components are in the shape of dovetail clips.

[0008] In one specific embodiment, the two anchoring components are respectively disposed at the end of the fixed end and the end of the free end of the pneumatic soft body, and the anchoring component is a disc with a cross hole in the center.

[0009] In one specific embodiment, the two anchoring components are respectively disposed at the end of the fixed end and the end of the free end of the pneumatic soft body. The anchoring component includes multiple brushes and a disc-shaped bracket connected to the end of the pneumatic soft body. The bracket has multiple straight holes drilled around its periphery in an equally spaced manner for fixing the brushes, and each brush is fixed in the corresponding straight hole.

[0010] In one specific embodiment, the outer surface of the flexible covering structure capsule is provided with multiple reinforcing rings.

[0011] In one specific embodiment, the outer surface of the flexible covering structure capsule is provided with multiple fiber strips along the direction from one end to the other.

[0012] In one specific embodiment, the material of the flexible coating structure is a flexible polymer material.

[0013] In one specific embodiment, the flexible polymer material is HDPE.

[0014] In one specific embodiment, the spring is a metal spring or a polymer spring.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. The invention has a fast response speed: After the controlled airflow is injected into the flexible covering structure capsule, the airflow propagates along the spiral path of the flexible covering structure capsule. The flexible covering structure capsule expands one revolution at a time along the spiral path of the spring. The expansion of the flexible covering structure capsule one revolution at a time drives the spring to extend axially in sync, realizing the pneumatic soft body to extend one revolution at a time towards its free end. This shortens the air transmission path and can directly act on the contact surface between the flexible covering structure capsule and the spring. Compared with the traditional design where the spring is directly built into the flexible covering structure, there is no need to fill the necessary redundant space of the built-in cavity in the structure first, which greatly reduces the deformation waiting time. The structure can be extended within a few seconds, which is suitable for situations where rapid deployment is required.

[0017] 2. This invention effectively improves the extension ratio: Compared to the traditional design where the spring is directly embedded in the flexible covering structure, the flexible covering structure of this invention encapsulates the spring along the spring's spiral path, one turn at a time, within its inner cavity. The elastic deformation of the flexible covering structure and the spring are precisely coordinated, enabling extension deformation several times the original length, without local jamming or stress concentration during the deformation process. In confined space operation scenarios (such as pipeline inspection robots and precision equipment internal maintenance robots), it can flexibly move through narrow passages. By connecting multiple pneumatic soft bodies in parallel and cooperating with the pneumatic drive unit, it can bend and deform to avoid obstacles, significantly improving its adaptability to complex environments.

[0018] 3. This invention is suitable for confined spaces and complex shapes: The flexible encapsulation structure of this invention encapsulates the spring in its inner cavity along the spiral path of the spring, eliminating the need for a separate internal chamber. The flexible encapsulation structure directly adheres to the surface of the spring, greatly reducing redundant space. While ensuring deformation performance, it is smaller and more compact, making it more suitable for space-constrained working environments.

[0019] 4. The invention has a simple structure and is easy to manufacture: It adopts a minimalist combination design of spring and flexible encapsulation structure. The materials used are readily available. The assembly process does not rely on complex processes such as silicone casting. It is only necessary to encapsulate the spring in its inner cavity by wrapping the flexible encapsulation structure along the spiral path of the spring one turn at a time. The operation steps are simplified, which not only reduces the manufacturing difficulty, but also adapts to the needs of mass production. It helps to control production costs and improve production efficiency, and promotes the popularization of the technology to low-cost application scenarios (such as civilian service robots and experimental robots for education and scientific research).

[0020] 5. The invention features low-energy drive: it is driven solely by changes in air pressure, eliminating the need for complex electrical control or high-power components, thereby reducing energy loss and equipment burden at the source. Attached Figure Description

[0021] Figure 1 This is a front view of the pneumatic software of the present invention.

[0022] Figure 2 This is a schematic diagram of the pneumatic soft body of the present invention after inflation.

[0023] Figure 3 This is a cross-sectional view of the pneumatic soft body of the present invention after inflation.

[0024] Figure 4 This is a diagram of the spring structure of the present invention.

[0025] Figure 5 This is the flexible encapsulated structure capsule of the present invention.

[0026] Figure 6 This is a schematic diagram of the pneumatic software assembly process of the present invention.

[0027] Figure 7 This is a schematic diagram of the structure of the endoskeleton pneumatic soft robot suitable for planar crawling according to the present invention (the anchoring component is in the shape of a dovetail clip).

[0028] Figure 8 This is a schematic diagram of the structure of the endoskeleton pneumatic soft robot suitable for climbing poles according to the present invention (the anchoring component is a disc with a cross hole in the center).

[0029] Figure 9 This is a schematic diagram of the structure of the endoskeleton pneumatic soft robot for crawling in pipes according to the present invention (the anchoring component includes multiple brushes and a disc-shaped support connected to the end of the pneumatic soft robot).

[0030] In the diagram: 1. Spring; 2. Flexible encapsulated structure; 3. Anchoring component; 4. Pneumatic soft body; 5. Cross hole; 6. Disc; 7. Support; 8. Brush; 9. Open end; 10. Closed end. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0032] refer to Figures 1 to 5An endoskeleton pneumatic soft robot includes: a helical pneumatic soft body 4, two anchoring components 3, and a pneumatic drive unit connected to the pneumatic soft body 4. The pneumatic soft body 4 includes a strip-shaped flexible covering structure capsule 2 and a flexible endoskeleton, wherein the flexible endoskeleton is a spring 1. The two ends of the flexible covering structure capsule 2 are an open end 9 and a closed end 10, respectively. The end of the pneumatic soft body 4 near the open end 9 of the flexible covering structure capsule 2 is a fixed end, and the other end of the pneumatic soft body 4 is a free end. The two anchoring components 3 are respectively connected to the fixed end and the free end of the pneumatic soft body 4. The assembly process of the flexible covering structure capsule 2 and the spring 1 is as follows. Figure 6 As shown, the flexible encapsulated structure 2 encloses the spring 1 within its inner cavity, spiraling along its path. The end of the flexible encapsulated structure 2's opening 9 is fixedly connected to the corresponding position of the spring 1. The opening 9 of the flexible encapsulated structure 2 is connected to the pneumatic drive unit, and the connection between the opening 9 of the flexible encapsulated structure 2 and the pneumatic drive unit is sealed using PTFE tape or a sealing film. After the flexible encapsulated structure 2 and the spring 1 are assembled, the flexible encapsulated structure 2 conforms to the contour of each coil of the spring 1.

[0033] Gas is injected from the opening end 9 of the flexible covering structure capsule 2 by a pneumatic drive unit. The airflow propagates along the spiral path of the flexible covering structure capsule 2. The flexible covering structure capsule 2 expands one revolution at a time along the spiral path of the spring 1. The expansion of the flexible covering structure capsule 2 one revolution at a time drives the spring 1 to extend axially in sync, so as to realize the extension of the pneumatic soft body 4 in one revolution away from its fixed end.

[0034] The progressively increasing air pressure causes spring 1 to be stretched axially, and the distance between the spring coils gradually increases. Since spring 1 has extremely low stiffness, only a very small amount of air pressure is needed to achieve significant axial elongation.

[0035] The flexible encapsulated structure 2 expands sequentially under the action of airflow, thereby pulling the spiral-shaped pneumatic soft body 4 to extend axially. Preferably, the outer surface of the flexible encapsulated structure 2 is provided with multiple reinforcing rings.

[0036] Preferably, the outer surface of the flexible covering structure capsule 2 is provided with multiple fiber strips along the direction from one end to the other.

[0037] Preferably, the flexible encapsulation structure 2 is made of a flexible polymer material.

[0038] Optionally, the flexible polymer material is HDPE, and the flexible coating structure made of HDPE has high elastic modulus and excellent sealing performance.

[0039] Optionally, the spring 1 is a metal spring or a polymer spring, and the spring 1 has good axial tensile strength. The spring 1 has a small pitch, and the number of spring coils can be determined according to the actual situation.

[0040] In the experiment, spring 1 is a slinky spring with 6 coils, the flexible encapsulation structure 2 is made of HDPE, the driving frequency of the pneumatic drive unit is 50Hz, and the ratio of the length of the spiral-shaped pneumatic soft body 4 after extension to its original length is 250%, which is a significant improvement over the existing technology.

[0041] Optionally, multiple pneumatic actuators 4 can be connected in series or parallel using connectors. The connectors are customized according to the size and interface position of the pneumatic actuators 4 and are 3D / 4D printed to ensure a good fit and structural stability. The connectors are made of shape memory materials, which can meet the shape adjustment requirements in dynamic operating scenarios. In series connection, multiple pneumatic actuators 4 are sequentially connected using connectors; in parallel connection, multiple pneumatic actuators 4 are laterally connected using connectors to form a lateral load-sharing structure, improving heavy-duty operation capabilities.

[0042] Specifically, the anchoring component 3 can adopt different structures. The combination of the pneumatic soft body 4 and the anchoring component 3 with different structures can make the robot suitable for various application scenarios such as climbing poles, traveling in pipes, and crawling on planes.

[0043] Specifically, the cross-section of a spring can be any shape, such as circular, square, triangular, or butterfly-shaped.

[0044] Preferably, such as Figure 7 As shown, the two anchoring components 3 are respectively disposed at the bottom of the fixed end and the bottom of the free end of the pneumatic soft body. The anchoring components 3 are in the shape of dovetail clips, and the two anchoring components 3 are respectively glued to the bottom of both ends of the pneumatic soft body 4.

[0045] The specific operation is as follows: 1. The robot is placed on a plane in its initial state; 2. Gas is injected into the flexible covering structure capsule 2. The flexible covering structure capsule 2 expands one revolution at a time along the spiral path of spring 1. The expansion of the flexible covering structure capsule 2 one revolution at a time causes spring 1 to extend axially in sync. The pneumatic soft body 4 extends one revolution at a time away from its fixed end. During this process, the anchoring component 3 at the fixed end is attached to the ground, providing a fulcrum for the extension of the pneumatic soft body 4, while the anchoring component 3 at the free end slides with the extension of the pneumatic soft body 4; 3. When air is pumped out of the flexible covering structure capsule 2, spring 1 gradually returns to its original length. The anchoring component 3 at the free end is attached to the traveling surface, providing a stable anchoring point. The anchoring component 3 at the fixed end detaches from the surface due to the reduced traction and moves with the movement of the pneumatic soft body until spring 1 returns to its original length. The anchoring component 3 precisely coordinates with the extension and retraction movements of the pneumatic soft body 4 in terms of timing; 4. By cyclically executing steps 2 to 3, and by controlling the rhythm of gas injection and extraction and controlling the air pressure intensity, a "grab-pull-release-move" movement mode similar to that of an inchworm can be completed, thereby enabling the robot to achieve stable and continuous directional crawling along a horizontal surface.

[0046] Multiple pneumatic soft bodies 4 can be connected in series through connectors to form a robot, which can perform tasks such as directional support, detection or grasping in space-constrained environments.

[0047] Preferably, such as Figure 8 As shown, the two anchoring components 3 are respectively set at the end of the fixed end and the end of the free end of the pneumatic soft body. The anchoring component 3 is a disc 6 with a cross hole 5 in the center. The robot can grasp the surface of the rod-shaped structure by means of such anchoring components 3. The robot with such anchoring components 3 is suitable for stable attachment, directional crawling and continuous propulsion on the surface of slender rod-shaped structures (such as pipes, ropes, cables, etc.). It is suitable for structural inspection, signal deployment and other scenarios in narrow spaces or complex environments.

[0048] When the robot is stationary, the anchoring component 3 surrounds and covers the surface of the rod-shaped structure, with the cross-shaped hole 5 contacting the rod body and forming a closed hole. When the robot is driven by air pressure and undergoes axial tensile deformation, the anchoring component 3 passively opens and fits tightly against the contact surface, forming multiple supporting contact areas to provide reliable adhesion.

[0049] After the cross-shaped hole 5 comes into contact with the contact surface, its opening direction and contact angle differ, resulting in a difference in the coefficient of friction between the forward and reverse directions, exhibiting frictional anisotropy. This characteristic makes the robot experience less resistance when crawling in the forward direction and increased friction when sliding in the reverse direction, thereby improving crawling stability and single-step efficiency.

[0050] The specific operation is as follows: 1. The robot is initially placed on the rod, and no gas is injected into the flexible covering structure capsule 2; 2. Positive pressure gas is periodically injected into the flexible covering structure capsule 2 through the pneumatic drive unit, causing the flexible covering structure capsule 2 to expand one revolution at a time along the spiral path of spring 1. The expansion of the flexible covering structure capsule 2 one revolution at a time drives the spring 1 to extend axially synchronously, and the pneumatic soft body 4 extends one revolution at a time away from its fixed end. During this process, the anchoring component 3 at the fixed end of the pneumatic soft body is in close contact with the surface of the rod structure, and the friction force it experiences is large, so it is anchored to the rod. The anchoring component 3 at the free end of the pneumatic soft body cannot maintain a close contact with the surface of the rod structure under the action of axial tension. Due to low friction, the anchoring component 3 at the free end of the pneumatic soft body moves along with the movement of the flexible covering structure capsule 2; 3: Gas is extracted from the flexible covering structure capsule 2 by the pneumatic drive unit, causing the flexible covering structure capsule 2 to contract. At the same time, the spring 1 contracts and resets under the action of elastic restoring force; During the contraction process, the anchoring component 3 at the free end of the pneumatic soft body gradually returns to the closed state, which is tightly attached to the rod-shaped surface; The anchoring component 3 at the fixed end of the pneumatic soft body further opens due to the contraction, and the friction force decreases. It moves towards the free end of the pneumatic soft body along with the movement of the pneumatic soft body 4; 4: By repeating the above steps 2 to 3, the robot can complete directional crawling motion on the rod surface.

[0051] It is suitable for stable attachment and continuous crawling on complex pole surfaces, and has significant advantages, especially in applications such as power cables and tree trunks.

[0052] Preferably, such as Figure 9 As shown, the two anchoring components 3 are respectively disposed at the fixed end and the free end of the pneumatic soft body. The anchoring component 3 includes multiple brushes 8 and a disc-shaped bracket 7 connected to the end of the pneumatic soft body 4. The bracket 7 has multiple straight holes drilled around its periphery in an equally spaced manner for fixing the brushes 8. Each brush 8 is fixed in the corresponding straight hole. Robots equipped with such anchoring components 3 are suitable for achieving stable attachment and directional crawling inside or on the external surface of pipes.

[0053] In the non-working state, all brushes 8 remain naturally straight. When the robot enters the pipe, the flexible covering structure 2 stretches and deforms. Due to the force of the pipe wall, the multiple brushes 8 of each anchoring component 3 are passively bent in the opposite direction of stretching. After bending, the multiple brushes 8 of each anchoring component 3 are in an umbrella-like, closed state, and the closed brushes 8 form multi-point contact with the inner wall of the pipe. The brushes 8 of the anchoring components 3 at both ends of the pneumatic soft body 4 have different degrees of closure, resulting in different frictional forces.

[0054] The specific operation is as follows: 1. The robot is placed in the pipe in its initial state; 2. Positive pressure gas is injected into the flexible covering structure capsule 2 through the pneumatic drive unit, causing the flexible covering structure capsule 2 to expand one revolution at a time along the spiral path of spring 1. The expansion of the flexible covering structure capsule 2 one revolution at a time causes spring 1 to extend axially synchronously, and the pneumatic soft body 4 extends one revolution at a time away from its fixed end. During this process, the contraction amplitude of the brush 8 of the anchoring component 3 at the fixed end of the pneumatic soft body is not as large as that of the brush 8 of the anchoring component 3 at the free end of the pneumatic soft body. The brush 8 of the anchoring component 3 at the fixed end of the pneumatic soft body is in close contact with the inner wall of the pipe, while the brush 8 of the anchoring component 3 at the free end of the pneumatic soft body is not in close contact with the inner wall of the pipe. The anchoring component 3 at the free end of the pneumatic soft body follows the gas flow. 3. Gas is extracted from the flexible covering structure capsule 2 by the pneumatic drive unit, causing the flexible covering structure capsule 2 to contract. At the same time, the spring 1 contracts and resets under the action of elastic restoring force. During this process, the contraction range of the brush 8 of the anchoring component 3 at the free end of the pneumatic soft body is not as large as that of the brush 8 of the anchoring component 3 at the fixed end of the pneumatic soft body. The brush 8 of the anchoring component 3 at the free end of the pneumatic soft body experiences greater friction, so the anchoring component 3 at the free end of the pneumatic soft body will not move. The anchoring component 3 at the fixed end of the pneumatic soft body is affected by the retraction, and its friction is small. The anchoring component 3 at the fixed end of the pneumatic soft body moves with the movement of the pneumatic soft body 4. 4. By repeating the above steps 2 to 3, the robot can move in the pipe.

[0055] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions and substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An endoskeleton pneumatic soft robot, characterized in that, The utility model relates to a pneumatic soft body, two anchor assemblies and a pneumatic driving unit connected with the pneumatic soft body, the pneumatic soft body comprises a flexible sheath structure capsule in strip shape and a flexible endoskeleton, the flexible endoskeleton is a spring, the two ends of the flexible sheath structure capsule are open end and closed end respectively, one end of the pneumatic soft body close to the open end of the flexible sheath structure capsule is a fixed end, the other end of the pneumatic soft body is a free end, the two anchor assemblies are connected with the fixed end and the free end of the pneumatic soft body respectively, the flexible sheath structure capsule covers the spring in its inner cavity along the spiral path of the spring, the end of the open end of the flexible sheath structure capsule is fixedly connected with the corresponding position of the spring, the open end of the flexible sheath structure capsule is connected with the pneumatic driving unit, and the connecting place of the open end of the flexible sheath structure capsule and the pneumatic driving unit is sealed. The two anchor assemblies are arranged at the bottom of the fixed end and the bottom of the free end of the pneumatic soft body respectively, and the anchor assemblies are dovetail shapes.

2. The endoskeleton pneumatic soft robot of claim 1, wherein, The two anchor assemblies are arranged at the end of the fixed end and the end of the free end of the pneumatic soft body respectively, and the anchor assemblies are circular discs with cross holes arranged at the center.

3. The endoskeleton pneumatic soft robot of claim 1, wherein, The two anchor assemblies are arranged at the end of the fixed end and the end of the free end of the pneumatic soft body respectively, and the anchor assemblies comprise a plurality of brushes, a disc-shaped support connected with the end of the pneumatic soft body, and a plurality of straight holes for fixing the brushes are drilled in the periphery of the support in equal division, and each brush is fixed on the corresponding straight hole.

4. The endoskeleton pneumatic soft robot of claim 1, wherein, The outer surface of the flexible sheath structure capsule is provided with a plurality of reinforcing rings.

5. The endoskeleton pneumatic soft robot of any one of claims 2-4, wherein, The outer surface of the flexible sheath structure capsule is provided with a plurality of fiber strips along the direction from one end to the other end.

6. The exoskeleton pneumatic soft robot of claim 5, wherein, The material of the flexible sheath structure is a flexible polymer material.

7. The exoskeleton pneumatic soft robot of claim 6, wherein, The flexible polymer material is HDPE.

8. The endoskeletal, pneumatically powered, soft-bodied robot of claim 7, wherein, The spring is a metal spring or a polymer spring.

9. The endoskeletal, pneumatically powered, soft-bodied robot of claim 8, wherein, ​

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