Multi-modal motion asymmetric soft actuator and application thereof

Abstract

The invention provides a multi-modal motion asymmetric soft actuator and application thereof, and belongs to the technical field of soft robots. The present invention comprises: at least one bending chamber for converting air pressure energy into directional bending motion; the at least one torsion chamber and the bending chamber are physically separated to form an independent bending chamber and an independent torsion chamber, and the bending chamber and the torsion chamber are respectively connected with an independent gas circuit; an asymmetric structure is arranged in the torsion chamber and is used for directly converting air pressure energy into rotating torque around the central axis of the module; by independently controlling air pressure input of the torsion chamber and the bending chamber which are asymmetrically arranged, torsion and bending motion can be independently achieved in a single module. According to the invention, an asymmetric structure is adopted as a whole, independent driving chambers with special functions and physical isolation are integrated in a single module, a mode of indirectly synthesizing torsion through motion coupling of a plurality of symmetrical chambers is abandoned, torsion motion in a target direction is directly output, and a driving source and control logic are simplified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soft robot, in particular to a multi-modal motion asymmetric soft actuator and its application, which is suitable for posture adjustment and fine operation in complex environments such as medical minimally invasive, industrial detection, disaster rescue, etc. BACKGROUND

[0002] Soft actuator has become a key executive component in the fields of medical minimally invasive, industrial detection and disaster rescue, due to its core advantages such as flexible structure, safe human-computer interaction ability and high adaptability in complex environment. The core development trend of soft actuator is focused on the integration of modularization and multi-degree-of-freedom motion. By realizing various motion functions through standardizing single modules, the system structure is greatly simplified, the control complexity is reduced, and the overall flexibility is significantly improved, which meets the needs of complex tasks such as serpentine crawling of snake-shaped robots and posture adjustment of precision instruments.

[0003] At present, there are mainly two technical paths to realize multi-degree-of-freedom motion of soft actuator: one is to connect multiple single-function actuation modules in series, and to realize overall motion by means of distributed control. However, this method leads to long structure and complex control. The other is to integrate multiple symmetrically distributed drive chambers in a single module, and to synthesize complex motion by coordinating the driving of different chambers. Although the latter improves the integration degree, it relies on the motion coupling of multiple symmetric chambers to realize indirect twisting and other complex motions, which has problems such as low driving efficiency, strong control coupling and complex structure. In particular, this motion synthesis method based on symmetric structure is difficult to realize high-performance direct twisting motion in a single module, which limits its application in fine operation and complex environment.

[0004] At present, the technical path to realize the composite motion of twisting and bending mainly includes two categories: one is to connect multiple single-degree-of-freedom modules in series, such as bending module and twisting module designed respectively, and to realize composite motion after connection; the other is to integrate multiple symmetrically arranged chambers (such as ring-shaped multi-chamber, left-right symmetric double-chamber) in a single module, and to realize two kinds of motion by coordinating the pressure of different chambers. However, both of these two paths have significant limitations, and cannot balance the structural simplicity and motion flexibility, which has become the core bottleneck restricting the development of soft actuator towards miniaturization and high precision.

[0005] As disclosed in the invention patent with publication number CN117103240A, a four-degree-of-freedom liquid-driven soft actuator adopts a single-module design, with a circular tube as the central framework, and four inclined cavity actuating assemblies (first to fourth inclined cavity actuating assemblies) arranged symmetrically on the outer surface. Each actuating assembly has an independent liquid chamber, liquid channel and liquid passage inside, and the liquid chamber and the outer surface of the assembly are recessed to form multiple expansion walls, with the thickness of the expansion walls designed in a gradient manner (e.g., first expansion wall < second expansion wall < third expansion wall), and the assembly is arranged axially along the circular tube. The two ends are fixed by first and second fixed assemblies to fix each actuating assembly and the circular tube, limit excessive deformation of the circular tube, and ensure movement stability.

[0006] The driving mode is liquid-driven (compatible with pneumatic), and multi-degree-of-freedom movement is achieved by controlling the liquid / gas pressure of different actuating assemblies. Bending movement: two groups of actuating assemblies arranged diagonally (e.g., first + second assemblies) are filled with liquid, and directional bending is generated by the difference in expansion wall thickness, which can realize bending in four directions: up, down, left and right. Torsional movement: two groups of actuating assemblies arranged in cross (e.g., second + fourth assemblies) are filled with liquid, and the non-collinear torque generated by the expansion of the assemblies drives the module to twist (clockwise / counter-clockwise) around the axial direction of the circular tube. Compound movement: bending movement accompanied by axial elongation, and torsion and bending can be combined by coordinated liquid filling of the assemblies.

[0007] However, it has the following disadvantages and deficiencies: 1. Torsional movement is an indirect and inefficient coupled movement; 2. Complex structure and control burden, integrating four independent drive chambers and corresponding flow channels; 3. Movement coupling and interference, as the four chambers are closely coupled in physical structure, driving one group of chambers may cause negligible interference to the shape or internal pressure of another group of chambers, affecting movement accuracy; 4. Performance limitation: the torsional movement generated by the symmetric chamber coupling is usually limited in angle and torque.

[0008] In the paper "Design and Implementation of Multi-Motion Mode Snake-Like Soft Robot", the snake-like soft robot has obvious deficiencies: a three-section driver is used in series design, the structure is redundant and the overall size is large, a single module can only realize bending or elongation in a single direction, cannot independently complete compound movement, and needs multiple modules to realize torsion and other actions, with poor narrow space adaptability. Each section of the driver relies on left and right double chambers to achieve bending by coordinated pressurization, without independent torsion chamber, with prominent movement coupling, complex control logic and slow response speed. At the same time, the corrugated cavity relies on slotting to limit radial expansion, and the conversion efficiency of gas pressure and bending angle is limited, the deformation effect is easily affected by the coordination accuracy of the chambers, and the overall movement flexibility and environmental adaptability are insufficient.

[0009] In summary, the soft robot in the prior art has the following defects: Complex structure and processing: achieving torsion + bending composite motion needs to rely on multi-chamber or multi-module series connection, large number of components (such as the invention patent with publication number CN117103240A contains 4 actuating assemblies, and the invention patent with publication number CN113400288A assembles 27 corrugated airbags), complicated assembly, and multiple sealing points of multi-chamber are prone to gas leakage.

[0010] Strong control coupling: multiple symmetric chambers and module layouts are adopted, and torsion and other movements need to rely on multi-chamber pressure cooperative control (such as CN117103240A needs to accurately adjust the pressure difference of the diagonal and cross assemblies), the control logic is complex, and the motion switching is prone to deformation coupling interference, and the precision is low.

[0011] Limited motion performance: the maximum angle and output torque of the torsion motion generated by the symmetric chamber coupling are limited by the basic bending motion, it is difficult to achieve a single module 80-degree large-angle torsion, and it cannot meet the demand of large torsion and strong operation scene.

[0012] Poor space adaptability: multi-chamber and multi-module design leads to increased radial size and decreased flexibility (such as CN113400288A has a large radial size due to multiple airbags and connecting rings), and cannot adapt to narrow spaces such as small pipelines and human body cavities. SUMMARY

[0013] Therefore, in order to solve the above structural disadvantages of the existing soft actuator for obtaining multiple degrees of freedom motion, the present application provides a non-symmetric soft actuator for multi-modal motion and its application, which adopts a non-symmetric structure (independent chamber and internal non-symmetric structure), integrates function-specific and physically isolated independent drive chambers in a single module, discards the way of indirectly synthesizing torsion through motion coupling of multiple symmetric chambers, directly outputs torsion motion in the target direction, and simplifies the drive source and control logic.

[0014] In order to achieve the above purpose, the present application provides the following technical solutions: In a first aspect, the present application provides a non-symmetric soft actuator for multi-modal motion, comprising: At least one bending chamber adopting a pneunet pneumatic network structure for converting gas pressure energy into directional bending motion; At least one torsion chamber, which is physically separated from the bending chamber to form independent bending and torsion chambers, and each is connected to an independent gas path; The torsion chamber is internally provided with a non-symmetric structure for directly converting gas pressure energy into rotational torque around the center axis of the module; By independently controlling the gas pressure input of the torsion chamber and the bending chamber, torsion and bending motion can be independently realized in a single module.

[0015] Preferably, the asymmetric structure comprises: inner helical protrusions arranged axially continuously along the inner wall of the torsion chamber; air cavity gaps arranged around the inner helical protrusions on the inner wall of the torsion chamber.

[0016] Preferably, the asymmetric structure comprises: inclined restriction blocks arranged oppositely on the inner wall of the torsion chamber, extending from the edge of the torsion chamber to the central axis to form an asymmetric inclined restriction structure for decomposing the linear expansion force into a torsion moment around the central axis; air cavity gaps arranged around the inclined restriction blocks.

[0017] Preferably, the asymmetric soft actuator comprises three independent chambers: one middle torsion chamber and two symmetrically distributed bending chambers. The torsion chamber is located at the center of the module, and the bending chambers are respectively located on the two sides of the torsion chamber to realize bidirectional bending motion. The bending chambers on the two sides are designed with asymmetric wall thicknesses of thin wall on one side and thick wall on the other side, and are arranged radially eccentrically.

[0018] Preferably, the asymmetric soft actuator comprises four independent chambers: two symmetrically distributed torsion chambers and two symmetrically distributed bending chambers. The torsion chambers are located at the two ends of the module, and the bending chambers are located in the middle of the module to realize bidirectional bending motion. The bending chambers on the two sides are designed with asymmetric wall thicknesses of thin wall on one side and thick wall on the other side, and are arranged radially eccentrically.

[0019] Preferably, the bending chamber comprises an air inlet, an air cavity passage, periodic wave crests, wave troughs and support ribs. The area of the wave trough is a thin-walled deformation area, the area of the wave crest is a thick-walled restriction area, and the support ribs separate the wave crest and the wave trough into independent deformation units to limit radial expansion and guide the bending direction.

[0020] Preferably, the bending chamber realizes 40-80 degree directional bending under 80kPa air pressure, and the torsion chamber generates a torsion angle of 50-80° under 60kPa air pressure.

[0021] Preferably, the torsion chamber and the bending chamber have a 2-3mm thickened chamber wall thickness.

[0022] In a second aspect, the application provides an application of the above-mentioned asymmetric soft actuator of multi-modal motion in posture adjustment and fine work in disaster rescue, industrial detection or medical minimally invasive complex environment.

[0023] The application realizes direct driving, decoupling control and compact integration of torsion and bending motion by innovative asymmetric chamber structure, independent gas path and physical isolation design, single module multi-chamber integration, breaks through the performance bottleneck of traditional symmetric structure, and provides an efficient solution for fine operation in narrow and complex environment. (1) The application discards the coupling of multiple symmetric chambers and directly outputs torsion motion through a single asymmetric chamber: an independent asymmetric torsion chamber is designed, which is provided with an internal helical protrusion or an inclined limiting block and other asymmetric structures, after the gas enters through the gas inlet of the torsion chamber, the pressure is uniformly distributed through the gas chamber gap, the asymmetric structure directly converts the linear expansion force into the rotation torque around the central axis, and pure torsion motion is realized. The torsion chamber can realize 50-80° pure torsion under 60kPa gas pressure, without relying on the pressure difference of multiple chambers or external transmission mechanism.

[0024] The traditional symmetric chamber coupling indirect synthesis torsion mode is abandoned, and a single asymmetric chamber is used to independently drive to simplify the number of driving sources, and only a single chamber gas pressure needs to be adjusted, and the control logic is direct.

[0025] (2) Reduce the coupling interference between motion modes and realize independent precise control: the torsion chamber and the bending chamber form independent chambers through physical separation, each chamber is provided with an independent gas path and a gas inlet, and the deformation interference during inflation is avoided. The torsion chamber focuses on outputting rotation torque, the bending chamber uses pneunet structure for directional bending, the motion modes are independent and do not depend on each other, and the functions are special. The bending and torsion motion can be independently controlled, for example, a single-sided bending chamber realizes 40-80° directional bending under 80kPa gas pressure, and there is no coupling interference with the torsion motion, and the control precision is improved.

[0026] (3) Optimize the asymmetric chamber structure to improve the integration and compactness: single module integrates multiple chambers, such as, Three-chamber layout: one middle torsion chamber and two symmetric bending chambers are integrated in a single module along the radial direction, replacing the multi-module series structure. For example, four-chamber layout: two symmetric torsion chambers (both ends) and two symmetric bending chambers (middle) are integrated axially, which adapts to the demand of narrow space. Each chamber is naturally separated by a partition wall without additional support skeleton, and the external dependence is reduced by utilizing the mutual constraint between the chambers, and the structure is compact without redundant series modules.

[0027] (4) Process advantage: modular integrated design, the torsion chamber is formed by melting and disappearing method, and the bending chamber is formed by block pouring method, which reduces the assembly link and the mold complexity.

[0028] (5) Break through the limitation of symmetric structure and realize single large-angle motion: Large-angle bending: the bending chamber adopts a pneunet structure, the wall thickness of the contraction part is smaller than that of the non-contraction part (asymmetric wall thickness design of single-thin-wall and double-thick-wall), and 40-80° directional bending is realized under 80kPa air pressure, and the two-way bending range covers the positive and negative directions of the Z-axis or the positive and negative directions of the Y-axis.

[0029] Large-angle torsion: the asymmetric torsion chamber directly converts air pressure energy through internal spiral protrusions or inclined limiting blocks, and 50-80° pure torsion is realized under 60kPa air pressure, breaking through the angle limitation of the coupled motion of the symmetric chamber, and the torsion angle of the traditional symmetric structure is usually <50°.

[0030] (6) Realize integration of multiple motion functions in a single module Three independent function chambers are integrated in a single module, including the middle torsion chamber and the two side bending chambers, and the three chambers realize torsion motion and left and right bending motion respectively. In the prior art, multiple modules are connected in series or multiple chambers are cooperatively controlled to realize torsion and bending motion, and the present application has the advantages that the single module has complete multi-degree-of-freedom motion ability due to the layout of the function-separated chambers, and the three chambers are independent in structure and have specific functions, so that accurate motion can be realized without complex cooperative control algorithm. Therefore, the present application realizes integration of multiple motion functions in a single module, reduces system complexity, and improves motion control accuracy and reliability.

[0031] (7) Realize motion decoupling control The three chambers are physically separated, each chamber is connected to an independent air path and a special air inlet interface, and the two side bending chambers adopt an asymmetric wall thickness design of single-thin-wall and double-thick-wall. Physical isolation and independent air path ensure that the deformation of each chamber does not interfere with each other when inflated, and the asymmetric wall thickness design makes the bending chamber only bend to the thick wall side when inflated. This structural design eliminates the possibility of motion coupling from the physical level. Therefore, the present application realizes precise independent control of torsion and left and right bending motion, and there is almost no interference between each motion mode, which significantly improves the control accuracy.

[0032] (8) Improve motion efficiency The inner wall of the middle torsion chamber is provided with continuous spiral protrusions, and the inflation force is directly converted into torsional moment through the constraint effect of the spiral protrusions on the chamber expansion. The two side bending chambers adopt a pneunet structure of the pneumatic network structure.

[0033] The spiral structure can effectively convert linear expansion into rotary motion, and the pneunet structure realizes efficient directional bending through its special air pressure-deformation characteristics. This specialized structural design optimizes the energy conversion efficiency. Therefore, the present application improves the utilization efficiency of driving energy and can produce larger motion angles and output torques under the same driving pressure.

[0034] (9) Enhance compactness of structure Three functional chambers are integrated inside a single module, achieving high integration of functions through optimized layout; the curved chambers on both sides simultaneously serve to limit the expansion of the torsion chamber. By integrating multiple motion functions in a single module, structural redundancy caused by multiple modules in series is avoided. At the same time, the mutual constraint between the chambers reduces the dependence on external support structures. Therefore, the invention achieves compactness of structure while maintaining multi-degree-of-freedom motion capability, improving space utilization efficiency.

[0035] (10) Improve environmental adaptability The "torsion + bidirectional bending" independent motion function integrated in a single module, combined with the high-efficiency directional deformation of the pneunet structure and the flexible adjustment capability of the spiral torsion chamber. The complete motion function and compact structure size enable the actuator to move flexibly in narrow spaces, while the precise independent control capability ensures operation precision in complex environments. Therefore, the invention is particularly suitable for complex environments such as rubble gaps and narrow passages, and can complete fine attitude adjustment and task operations.

[0036] (11) Simplify manufacturing process Adopting a modular integrated structure design, the three chambers are naturally separated by a partition wall, and each functional area has a regular structure. The regular structure design and clear functional zoning reduce the complexity of mold manufacturing, and the integrated structure reduces the assembly steps, facilitating the use of mature soft robot manufacturing processes. Therefore, the invention has the characteristics of simple manufacturing process and controllable cost, which is conducive to industrialization and popularization. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a schematic diagram of the first form of the three-dimensional structure of the invention.

[0038] Figure 2 is a schematic diagram of the first form of the semi-partial three-dimensional structure of the invention.

[0039] Figure 3 is a schematic diagram of the first form of the cross-sectional view of the invention.

[0040] Figure 4 is a schematic diagram of the first form of the right view and right view cross-sectional view, where the left side is the right view and the right side is the right view cross-sectional view.

[0041] Figure 5 is a model diagram of the first form.

[0042] Figure 6 is a schematic diagram of the second form of the three-dimensional structure of the invention.

[0043] Figure 7 Fig. 1 is a schematic diagram of a cross-section of a first form of the application. Figure 6 Fig. 2 is a schematic diagram of a cross-section in the A-A direction.

[0044] Figure 8 Fig. 3 is a schematic diagram of a cross-section of a second form of the application.

[0045] Figure 9 Fig. 4 is a schematic diagram of a right view and a right view cross-section of a second form of the application.

[0046] Figure 10 Fig. 5 is a schematic diagram of a model of a second form.

[0047] Figure 11 Fig. 6 is a schematic diagram of the internal structure of a twist chamber of a second form.

[0048] Figure 12 Fig. 7 is a schematic diagram of a perspective view of a third form of the application.

[0049] Figure 13 Fig. 8 is a schematic diagram of a half-perspective view of a third form of the application.

[0050] Figure 14 Fig. 9 is a schematic diagram of a cross-section of a third form of the application.

[0051] Figure 15 Fig. 10 is a schematic diagram of a right view and a right view cross-section of a third form of the application, with the left side being a right view and the right side being a right view cross-section.

[0052] Figure 16 Fig. 11 is a schematic diagram of a model of a third form.

[0053] Figure 17 Fig. 12 is a schematic diagram of the internal structure of a twist chamber of a third form.

[0054] Figure 18 Fig. 13 is a schematic diagram of the internal structure of a bend chamber of a third form.

[0055] In the figures, 1 is a first bend chamber; 11 is a first bend chamber air inlet; 12 is a first bend chamber trough; 13 is a first bend chamber crest; 14 is a first bend chamber end; 15 is a first bend chamber support rib; 16 is a first bend chamber air cavity passage; 2 is a first twist chamber; 21 is a first twist chamber air inlet; 22 is a first air cavity gap; 23 is an inner helical protrusion; 24 is a first chamber end; 25 is a first tilt limiting block; 3 is a second bend chamber; 31 is a second bend chamber air inlet; 32 is a second bend chamber trough; 33 is a second bend chamber crest; 34 is a second bend chamber end; 35 is a second bend chamber support rib; 36 is a second bend chamber air cavity passage; 4 is a second twist chamber; 41 is a second twist chamber air inlet; 42 is a second tilt limiting block; 43 is a second air cavity gap; 44 is a second chamber end. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0057] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom end" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0058] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "provided with", "sleeved / connected", "connected" and the like should be understood broadly, for example, "connected" can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be internal communication of two elements. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0059] The present application provides a kind of asymmetric soft actuator of multimodal motion, comprising: At least one bending chamber, pneunet pneumatic network structure is used, for converting gas pressure energy into directional bending movement.At least one torsion chamber, and the bending chamber is physically separated to form independent bending chamber and torsion chamber, and each is connected independent gas path.The asymmetric structure is arranged in the torsion chamber, for directly converting gas pressure energy into rotation torque around the center axis of module.By independently controlling the gas pressure input of the torsion chamber and the bending chamber, torsion and bending movement can be realized independently in single module.Pneunet pneumatic network structure includes gas inlet, air cavity channel, periodic wave crest, wave trough and support rib and the like.

[0060] It should be noted that the asymmetry in this invention refers not only to the internal asymmetric structure but also to the asymmetric arrangement between the individual chambers. In other words, the prominent feature of this invention is its overall asymmetric structure, which distinguishes it from current models. Current models have identical internal structures in each chamber. For example, a model might have two chambers that are symmetrically arranged and have completely identical internal structures, thus exhibiting axial symmetry. Alternatively, a model might have four chambers that are identical internally and symmetrically arranged to achieve bending and torsional movements.

[0061] The present invention provides three specific implementation methods, as follows: Example 1 like Figures 1-5 As shown, this asymmetric soft actuator has one torsion chamber and two bending chambers, as detailed below: The asymmetric soft actuator has a first bending chamber and a second bending chamber above and below a first torsion chamber, the first torsion chamber, the first bending chamber and the second bending chamber being physically separated into independent chambers. The first bending chamber and the second bending chamber adopt an asymmetric wall thickness design of "single-side thin wall and opposite-side thick wall", and are arranged eccentrically in the radial direction, so that when the single-side chamber is inflated, it only bends in the direction of the thick wall side, and the two chambers are independently controlled to bend in the left and right directions respectively, avoiding motion coupling. The first bending chamber and the second bending chamber adopt a pneunet pneumatic network structure, and the working process thereof embodies the precise cooperation of each component. The first bending chamber gas inlet serves as the pressure input end of the first bending chamber, and guides the gas into the first bending chamber along the X-axis direction, and distributes the pressure quickly and uniformly to the entire network through the first bending chamber gas cavity channel connected thereto. The design of the first bending chamber gas cavity channel ensures the synchronization and consistency of pressure transmission, and lays a foundation for subsequent overall deformation. Under the action of pressure, the periodic structure composed of the first bending chamber wave crest and the first bending chamber wave trough starts to deform cooperatively. The first bending chamber wave crest and the first bending chamber wave trough cooperatively generate directional expansion, while the region of the first bending chamber wave crest serves as a relatively stable area to maintain structural constraint, and the differential deformation of the two constitutes an effective hinge of the bending motion. The first bending chamber support rib plays a key role in deformation guidance and constraint in this process, which separates the continuous wave crest and wave trough structure into independent deformation units, effectively preventing mutual interference during deformation of each unit, while strictly limiting the radial expansion of the first bending chamber, forcing the deformation energy to be concentrated and orderly transmitted along the negative direction of the Z-axis. Under the cooperative action of the above components, the end of the first bending chamber is accurately driven to realize efficient and directional bending along the negative direction of the Z-axis. The whole movement process embodies the efficient conversion of gas pressure energy into mechanical deformation, wherein the gas cavity channel ensures the uniformity of energy input, the wave crest and wave trough structure realizes the directional guidance of deformation, the first bending chamber support rib provides the necessary deformation constraint, and the end of the first bending chamber completes the precise output of the movement. This structure and function integrated design enables the first bending chamber to achieve a bending effect of 60-80 degrees under a gas pressure of 80 kpa.

[0062] The second bending chamber adopts a pneunet pneumatic network structure symmetrical to the first bending chamber to realize directional bending along the positive direction of the Z axis. The second bending chamber gas inlet guides the gas into the second bending chamber along the X axis, and the pressure is uniformly transmitted through the second bending chamber air cavity channel. The periodic structure composed of the second bending chamber wave trough and the second bending chamber wave peak alternately responds to the pressure, and the second bending chamber wave peak and the second bending chamber wave trough cooperatively produce directional expansion, the second bending chamber wave peak is kept constrained, and a bending hinge is formed. The second bending chamber support rib separates the deformation unit and limits the radial expansion, so that the deformation energy is concentrated and transmitted along the positive direction of the Z axis. Finally, the second bending chamber end is driven to complete efficient directional bending along the positive direction of the Z axis, and the upper chamber is matched to realize bidirectional bending, which can reach a bending angle of 60-80 degrees under a gas pressure of 80 kpa, thereby providing bidirectional attitude adjustment capability for the actuator.

[0063] The first torsion chamber is a core functional unit for realizing independent torsion movement. The asymmetric structure in the first torsion chamber includes: an inner spiral protrusion, which is continuously arranged along the inner wall of the torsion chamber. An air cavity gap is opened in the inner wall of the torsion chamber and surrounds the inner spiral protrusion. The air cavity gap is preferably the gap between the inner spiral protrusions. After inflation, the gas enters the air cavity gap and realizes torsion movement through the action of the inner spiral protrusion.

[0064] The gas first enters the first torsion chamber from the first torsion chamber gas inlet, and then realizes rapid and uniform pressure distribution through the first air cavity gap surrounding the inner spiral protrusion. This design ensures that each part of the chamber can respond to the change in gas pressure synchronously. Under the action of uniform gas pressure, the inner spiral protrusion of the inner wall begins to play a key role in mechanics. This structure efficiently decomposes the linear force generated when the chamber expands into a rotational torque around the central axis X axis with a specific spiral angle. The inner spiral protrusion of the spiral structure guides the deformation of the chamber material along a predetermined trajectory, directly converting gas pressure energy into rotational kinetic energy. The transmission process drives the first chamber end to produce pure rotational motion around the X axis center. During the entire movement process, the gas inlet ensures stable energy input, the first air cavity gap ensures uniform pressure distribution, the inner spiral protrusion realizes directional conversion of mechanics, and the first chamber end completes precise output of motion. This unique design based on the spiral constraint principle enables the first torsion chamber to independently produce pure and controllable torsional deformation without the need for external transmission mechanisms. The first torsion chamber can achieve a torsion effect of 70-80 degrees under a gas pressure of 60 kpa.

[0065] The core innovation of the multi-modal motion asymmetric soft actuator lies in its unique architecture design of three chambers working in coordination. Through the precise cooperation of the first torsion chamber in the middle and the first and second bending chambers symmetrically distributed on both sides, the structure realizes complete freedom of motion within a single module, while forming beneficial mechanical interactions between the chambers.

[0066] The first and second bending chambers on both sides adopt an optimized pneunet pneumatic network structure. Their periodic design with alternating wave crests and troughs not only realizes efficient bending of 60-80 degrees in their respective directions, but more importantly, they act as natural structural constraint layers, effectively limiting the radial expansion of the middle torsion chamber. This constraint mechanism enables the deformation of the internal helical protrusions in the torsion chamber to be more concentrated into rotational torque around the X-axis when inflated, rather than being dissipated in radial expansion, thereby significantly improving the efficiency of torsional motion. Experimental data show that at a working pressure of 60 kPa, the design can achieve a pure torsion angle of 70-80 degrees, fully verifying the effectiveness of this coordinated constraint mechanism.

[0067] The three chambers are precisely controlled through independent air inlets and air path systems, each equipped with a dedicated air chamber channel or air chamber gap to ensure uniformity of pressure distribution and consistency of response. This physically isolated design enables independent control of torsion and bidirectional bending motion, with little interference between them, solving the common problem of motion coupling in traditional soft actuators. In terms of overall performance, the actuator can achieve bidirectional bending of 60-80 degrees at 80 kPa, and torsion of 70-80 degrees at 60 kPa, demonstrating excellent motion performance. More importantly, the coordinated constraint relationship between the chambers creates a "1+1>2" effect, where the bending chambers on both sides not only fulfill their own functions, but also improve the torsion efficiency of the middle torsion chamber by limiting its redundant deformation; the presence of the middle torsion chamber also provides a stable support foundation for the bending chambers on both sides. Specifically, the bending chambers on both sides can limit the radial expansion of the middle torsion chamber during the torsion motion process after inflation. Without the bending chambers on both sides, the torsion chamber would have a larger radial expansion after inflation. Therefore, not only does the actuator achieve torsion and bending motion, but it also has the advantage of mutual radial expansion limitation.

[0068] Example 2 As shown in Figures 6-11 , the asymmetric soft actuator has one torsion chamber and two bending chambers, and its specific composition is the same as that of Example 1, except for the asymmetric structure in the first torsion chamber. The asymmetric structure in Example 2 includes: The tilt limiting blocks are arranged in pairs opposite to each other in the torsion chamber and extend from the edge of the torsion chamber to the central axis in a tilt manner, forming an asymmetrically distributed tilt constraint structure for decomposing the linear expansion force into a torsion moment around the central axis. The air cavity gaps are arranged around the tilt limiting blocks, and the air cavity gaps are preferably the gaps between the tilt limiting blocks. After being filled with gas, the gas enters the air cavity gaps and realizes torsion movement through the action of the tilt limiting blocks. Specifically: The first torsion chamber of the actuator is a core functional unit for realizing independent torsion movement, which is composed of a first torsion chamber gas inlet, a first torsion chamber air cavity gap, a first tilt limiting block and a first chamber end. After the gas enters through the first torsion chamber gas inlet, it realizes rapid and uniform distribution of pressure through the first air cavity gap, ensuring that each part of the chamber responds synchronously to changes in gas pressure. Two rows of first tilt limiting blocks are arranged opposite to each other in the chamber, and the structure extends from the edge of the chamber to the middle of the chamber in a tilt manner, forming a constraint structure with a slope. When the chamber expands under the action of gas pressure, the first tilt limiting block directionally constrains and mechanically decomposes the expansion force, converting the linear expansion force into a torsion moment around the central axis; under the driving of the moment, the chamber material deforms along the tilt trajectory of the limiting block, and finally drives the first chamber end to produce a controllable torsion movement around the central axis. Through the mechanical guiding action of the first tilt limiting block, the structure can directly convert gas pressure energy into torsion kinetic energy without the need for external transmission mechanisms, realizing pure and controllable torsion deformation. The working principles of the two curved chambers on the two sides are the same as those of embodiment 1, and will not be described here. The curved chambers on the two sides cooperate with each other to make the actuator have a multi-modal motion capability of “bidirectional bending + torsion”, which is suitable for posture adjustment and operation requirements in narrow and complex environments. The curved chamber of the structure can achieve a bending angle of 60-80 degrees under a gas pressure of 80 kpa, but the torsion performance is about 50-70 degrees.

[0069] Embodiment 3 The difference between this embodiment 3 and embodiments 1 and 2 is that this embodiment 3 includes four independent chambers: two symmetrically distributed torsion chambers (first torsion chamber and second torsion chamber) and two symmetrically distributed bending chambers (first bending chamber and second bending chamber). The torsion chambers are located at both ends of the module, and the bending chambers are located in the middle of the module for realizing bidirectional bending movement; the bending chambers on the two sides adopt an asymmetric wall thickness design of single-sided thin wall and opposite-sided thick wall, and are arranged eccentrically along the radial direction.

[0070] As Figures 12-18 shown, the asymmetric soft actuator has two torsion chambers and two bending chambers. In the actuator configuration, a four-chamber symmetric layout is adopted to realize the multi-degree-of-freedom motion capability integrated in a single module. Through the cooperative work of the four functionally specific and structurally optimized chambers, the asymmetric soft actuator realizes bidirectional bending along the Y axis and pure torsion movement around the X axis.

[0071] The first bending chamber and the second bending chamber located in the center of the structure are responsible for the bending movement in the Y-axis direction. Among them, the first bending chamber realizes the directional bending in the negative direction of the Y-axis, the second bending chamber realizes the directional bending in the positive direction of the Y-axis, and the second bending chamber realizes the directional bending in the negative direction of the Y-axis. Both of the two bending chambers adopt an optimized pneunet pneumatic network structure, which generates accurate directional deformation when pressurized through the periodically arranged wave crest and trough structure inside. The principle is similar to the first, which will not be repeated here. The first bending chamber and the second bending chamber in this structure are different from the bending chamber in embodiment 1 in that the wave crest and the wave trough in this structure are arranged inside the bending chamber, and the outside is a smooth surface, as shown in Figure 18 . While the wave crest and the wave trough of embodiments 1-2 are arranged outside the bending chamber, as shown in Figure 5 , 10 . Those skilled in the art can choose according to actual needs, which does not make special restrictions, and it also cannot constitute a limitation on the scope of protection of the claims of the present application.

[0072] The torsion function unit arranged at both ends of the structure adopts a second tilt limiting block design. Among them, the first tilt limiting block in the first torsion chamber and the second tilt limiting block in the second torsion chamber are arranged in a 180-degree flip, forming an asymmetric structure. The first torsion chamber and the second torsion chamber serve as torsion units, each containing a complete mechanical conversion system: the first torsion chamber inlet and the second torsion chamber inlet as the pressure input end, ensuring the stable injection of gas; the second tilt limiting block in the first torsion chamber and the second torsion chamber as the core conversion element, adopting an asymmetric structure that tilts from the chamber edge to the central axis; the second gas cavity gap realizes uniform distribution of pressure; and the second chamber end as the movement output end completes the rotational displacement. The second gas cavity gap is preferably the gap between the second tilt limiting blocks. After inflation, the gas enters the gas cavity gap and realizes torsional motion through the action of the tilt limiting block.

[0073] When a pure torsional motion around the X-axis is needed, the first torsion chamber and the second torsion chamber are pressurized at the same time, and the second tilt limiting blocks in the two chambers work cooperatively to decompose the radial expansion force of the cavity material into tangential components through the inclined surface. These tangential components are integrated in the circumferential direction to form a unified rotational torque, which drives the respective second chamber ends to produce synchronous torsional motion. This design of symmetrical work of the double torsion chamber ensures the balanced generation of the torsional torque and effectively eliminates the possible parasitic motion.

[0074] The innovation of the four-chamber architecture lies in the high decoupling and precise coordination of each motion unit. By independently controlling the pressure state of the four chambers, not only basic bending and twisting movements can be achieved, but also precise motion trajectory planning in three-dimensional space can be completed through complex pressure combinations. The four chambers maintain functional independence while forming an organic whole through a compact structural layout, demonstrating significant progress in soft actuator design and motion control. The structure places the twisting chamber on both sides, resulting in better twisting performance, but the bending chamber in the middle is squeezed by both sides, limiting the bending performance. It produces a twisting angle of 50-70 degrees at 60 kpa gas pressure and a bending angle of 40-60 degrees at 80 kpa gas pressure.

[0075] In embodiments 1-3 of the present application, the twisting chamber and the bending chamber are separated by a thickened chamber wall thickness of 2-3 mm to form independent asymmetric chambers. The first and second inclined limiting blocks of embodiments 2 and 3 are 180 degrees apart, i.e., the inclined directions of the limiting blocks are opposite, also forming an asymmetric structure.

[0076] The above three kinds of multi-modal motion asymmetric soft actuator structures of the present application all have the advantage of easy manufacturing, and the process design is specially adapted to the structural characteristics of each chamber. Among them, the twisting chamber is uniformly formed by the lost foam method, and the bending chamber is made by the block pouring method. The internal structure of the twisting chamber is complex. Whether it is the first internal spiral protrusion, the second first inclined limiting block layout, or the third asymmetric structure of the second inclined limiting block at both ends of the twisting chamber, it can rely on the fusible core mold assisted by the lost foam method to accurately reproduce the fine functional features such as air cavity gap, internal spiral protrusion, and inclined limiting block, ensuring the structural precision and spatial outline integrity required for mechanical conversion, and avoiding the processing difficulties of complex internal structures. The bending chamber adopts an optimized Pneunet pneumatic network structure, and each bending chamber can be independently made by block pouring, such as the upper and lower bending chambers of the first type, the two bending chambers on the sides of the second type, and the two bending chambers in the middle of the third type. The block pouring method can complete the pouring and forming of structures such as wave peaks, wave troughs, support ribs, and air cavity channels, and then integrated with the twisting chamber through an appropriate assembly method. This "twisting chamber lost foam method + bending chamber block pouring method" process combination adapts to the structural needs of different chambers, greatly reduces the processing difficulty, and realizes efficient and low-cost forming.

[0077] The working principle of the present application is as follows: 1. Single-chamber asymmetric structure to achieve twisting and bending motion: a single asymmetric chamber is used, the twisting chamber achieves twisting motion through an internal spiral protrusion structure, and the two side chambers independently complete bending motion. The twisting and bending motions are integrated in a single module, without the need for multiple chamber coordination or multiple module series connection.

[0078] 2. The layout structure of integrating three independent function chambers in a single module: three independent chambers are arranged radially inside the module, including a torsion chamber in the middle and two bending chambers symmetrically distributed on both sides, the three chambers respectively realize torsion movement and left and right bending movement, replace the structure of multiple modules in series or symmetric multi-chamber coupling control in the prior art, and realize the integration of multiple movement functions in a single module.

[0079] 3. The internal spiral structure design of the middle torsion chamber: the torsion chamber is cylindrical, an internal spiral protrusion is arranged on the inner wall of the torsion chamber in the axial direction, the inflation force is directly converted into a torsion torque around the center axis of the module through the constraint effect of the internal spiral protrusion on the chamber expansion, and the torsion movement is independently realized without relying on the pressure difference of multiple chambers.

[0080] 4. The asymmetric wall thickness and eccentric layout of the two bending chambers: the bending chambers are arranged on both sides of the module, each bending chamber adopts an asymmetric wall thickness design of “single thin wall and opposite thick wall”, and is arranged eccentrically in the radial direction, so that the single chamber is only bent to the thick wall side when inflated, and the two chambers are independently controlled to bend in left and right directions, respectively, to avoid movement coupling.

[0081] 5. The isolation and independent air path design of the three chambers: the three chambers are separated into independent chambers by a thickened chamber separation layer with a thickness of 2-3 mm, and each chamber is connected to an independent air path and a dedicated air inlet, so that the inflation deformation of each chamber does not interfere with each other, and the torsion and left and right bending movements are accurately and independently controlled.

[0082] By providing driving pressure to a single asymmetric chamber, the bending and torsion movements are directly driven, and the two movement modes are excited simultaneously on the single actuator module.

[0083] The Pneunet structure design of the two bending chambers: the left and right bending chambers both adopt the Pneunet pneumatic network structure, through the pressure-deformation conversion characteristics of the Pneunet structure, the chamber is folded and bent in the direction of the contraction part when inflated, the radial expansion is limited, and the bending efficiency and angle controllability are improved.

[0084] The present application integrates the “torsion + bidirectional bending” independent movement functions in a single module, combines the efficient directional deformation characteristics of the Pneunet structure bending chambers on both sides, and the flexible angle adjustment advantages of the middle spiral torsion chamber, can flexibly adjust the posture in complex environments such as ruins gaps and narrow channels, accurately complete the shuttle and exploration operations, and significantly improve the movement flexibility.

[0085] The application can also be applied to posture adjustment and operation in narrow and complex environments in the fields of disaster rescue, industrial detection, medical minimally invasive operation, underwater operation and the like.

[0086] The above merely provides the preferred embodiments of the application. The protection scope of the application is not limited to this. Any person skilled in the art can make equivalent replacements or changes to the technical scheme of the application and the improvement concept thereof within the technical scope disclosed by the application, which should be covered by the protection scope of the application.

Claims

1. An asymmetric soft body actuator of multimodal motion, characterized in that, include: At least one bending chamber, employing a pneunet aerodynamic network structure, is used to convert air pressure energy into directional bending motion; At least one torsion chamber is physically separated from the bending chamber to form independent bending and torsion chambers, and each is connected to an independent air passage; The torsion chamber is equipped with an asymmetrical structure to directly convert air pressure energy into rotational torque around the central axis of the module. By independently controlling the air pressure input to the torsion chamber and bending chamber, torsion and bending movements can be achieved independently within a single module.

2. The asymmetric soft actuator for multimodal motion according to claim 1, characterized in that, The asymmetric structure includes: The inner spiral protrusion is continuously arranged axially along the inner wall of the torsion cavity. The air cavity gap is formed in the inner wall of the torsion cavity and surrounds the inner spiral protrusion.

3. The asymmetric soft actuator for multimodal motion according to claim 1, characterized in that, The asymmetric structure includes: Inclined limiting blocks are arranged vertically opposite each other in the torsion chamber and extend obliquely from the edge of the torsion chamber toward the central axis to form an asymmetrically distributed inclined constraint structure, which is used to decompose the linear expansion force into a torsional moment about the central axis. The air cavity gap surrounds the inclined limiting blocks.

4. The asymmetric soft actuator for multimodal motion according to claim 1, characterized in that, It includes three independent chambers: a central torsion chamber and two symmetrically distributed curved chambers; The torsion chamber is located at the center of the module, and the bending chambers are located on both sides of the torsion chamber to enable bidirectional bending motion. The curved chambers on both sides adopt an asymmetrical wall thickness design with thin walls on one side and thick walls on the opposite side, and are arranged radially eccentrically.

5. The asymmetric soft actuator for multimodal motion according to claim 1, characterized in that, It includes four independent chambers: two symmetrically distributed torsional chambers and two symmetrically distributed curved chambers; The torsion chamber is located at both ends of the module, and the bending chamber is located in the middle of the module, which is used to realize bidirectional bending motion; The curved chambers on both sides adopt an asymmetrical wall thickness design with thin walls on one side and thick walls on the opposite side, and are arranged radially eccentrically.

6. The asymmetric soft actuator for multimodal motion according to claim 1, characterized in that, The curved chamber includes an air inlet, an air passage, periodic peaks and troughs, and supporting ribs; The trough region is a thin-walled deformation zone, and the crest region is a thick-walled constraint zone. The supporting ribs separate the crests and troughs into independent deformation units, restricting radial expansion and guiding the bending direction.

7. The asymmetric soft actuator for multimodal motion according to claim 1, characterized in that, The bending chamber achieves directional bending of 40 to 80 degrees under 80 kPa air pressure, and the torsion chamber generates a torsion angle of 50 to 80 degrees under 60 kPa air pressure.

8. The asymmetric soft actuator for multimodal motion according to claim 1, characterized in that, The torsion chamber and the bending chamber have a 2-3 mm thickened chamber wall.

9. The application of the multimodal motion asymmetric soft actuator according to any one of claims 1-8 in attitude adjustment and precision operation in complex environments such as disaster relief, industrial inspection or minimally invasive medical procedures.

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