A soft actuator and its driving method for realizing omnidirectional bending and torsional motion in space.

Abstract

This invention discloses a soft actuator and its driving method for realizing omnidirectional bending and torsional motion in space. The soft actuator includes a central layer, four limiting layers, two first strain layers, and two second strain layers. The central layer is a strip with a square radial cross-section. The four limiting layers are respectively attached and fixed to the four side walls of the central layer. The first strain layers and the second strain layers have a mirror-symmetrical structure. Both are composed of a front-end ventilation module, multiple intermediate ventilation modules, and a rear-end ventilation module arranged in a straight line with equal spacing from front to back. An oblique through-slot is formed between each pair of adjacent ventilation modules. Each ventilation module has a chamber, and the chambers between adjacent ventilation modules are connected to form an air chamber. The four strain layers are alternately arranged and attached and fixed to the four limiting layers. This soft actuator can freely select the bending and torsional directions through pneumatic drive, realizing hovering and sweeping at any position in a certain area of ​​space.

Description

Technical Field

[0001] This invention relates to the field of soft robot technology, and in particular to a soft actuator that realizes omnidirectional bending and twisting motion in space. Background Technology

[0002] Compared to traditional robots, soft robots possess the characteristics of being flexible and deformable, exhibiting better adaptability, flexibility, and safety. The soft structure of soft robots allows them to adapt to various irregular shapes and curved surfaces, enabling them to traverse and perform tasks in complex environments. Furthermore, the use of soft materials in soft robots makes them resistant to collisions and deformations, resulting in higher toughness and durability. Elastic actuators, as an important component of soft robots, were first introduced into soft robot design by Correll N et al. with rib-like structures, but their structure limited the bending performance of elastic actuators. Later, Mosadegh B et al. proposed a fast-acting pneumatic mesh structure elastic brake, improving the bending performance of elastic actuators. Wang T et al. further generated coupled bending and torsional motions by adjusting the angle of the soft actuator, but the deformation that a single soft actuator can produce is limited, only achieving deformation in a single direction. Summary of the Invention

[0003] The purpose of this invention is to provide a soft actuator for realizing omnidirectional bending and torsional motion in space, which solves the above-mentioned technical problems.

[0004] Another objective of this invention is to provide a driving method for the above-mentioned soft actuator that realizes omnidirectional bending and torsional motion in space.

[0005] Therefore, the technical solution of the present invention is as follows:

[0006] A soft actuator for achieving omnidirectional bending and torsional motion in space includes an actuator mechanism comprising a central layer, four constraint layers, two first strain layers, and two second strain layers. The central layer is a strip-shaped cube with a square radial cross-section. The constraint layers are sheet-like bodies with an isosceles trapezoidal radial cross-section. The four constraint layers are fixed to the four side walls of the central layer by adhering to the wall surface of the central layer with their narrowest side surfaces. The first strain layer is a strip-shaped body with an isosceles trapezoidal radial cross-section, which is integrally formed by sequentially connecting and molding a front-end ventilation module, multiple intermediate ventilation modules, and a rear-end ventilation module arranged in a straight line at equal intervals from front to back, with a gap formed between each pair of adjacent ventilation modules. An oblique through-slot extends through the width of the strain layer; each ventilation module has a chamber, and the chambers between adjacent ventilation modules are connected, forming an air chamber within the first strain layer; the second strain layer has the same structure as the first strain layer and is mirror-symmetrical with the first strain layer; the two first strain layers are fixed to the constraint layer located on a set of opposite sidewalls of the central layer by means of their small-sized layers adhering to the large-width side of the constraint layer, and the two second strain layers are fixed to the constraint layer located on another set of opposite sidewalls of the central layer by means of their small-sized layers adhering to the large-width side of the constraint layer; the central layer, constraint layer, first strain layer, and second strain layer are all made of elastic material.

[0007] Furthermore, the elastic material is silicone with a hardness of 0.5HA to 2HA.

[0008] Furthermore, the axial length of the confinement layer is the same as that of the central layer, the width of the narrow side layer is the same as the width of the sidewall of the central layer 1, and the angle between the wide side layer and its adjacent inclined plane is 50° to 80°; the thickness of the confinement layer is 1 mm to 3 mm.

[0009] Furthermore, in each strain layer, the angle α between the direction of the inclined through groove and the axial direction of the strain layer is 50° to 80°.

[0010] Furthermore, each strain layer has a connecting end on the front end face of the first ventilation module, and the inner cavity of the connecting end is connected to the air chamber of the strain layer.

[0011] Furthermore, in each strain layer, the width of the oblique through-slot formed between adjacent ventilation modules is 1mm to 3mm.

[0012] Furthermore, in each strain layer, the first-end ventilation module is a block with an inverted isosceles trapezoidal radial cross-section, and a chamber with the same inverted isosceles trapezoidal radial cross-section is formed from its bottom surface; wherein, the chamber of the first-end ventilation module is composed of a front chamber and a rear chamber that are connected, and the front chamber is connected to the front end face of the first-end ventilation module through a ventilation hole. The axial length of the front chamber is greater than the axial length of the rear chamber, and the radial height is greater than the radial height of the rear chamber; the rear end face of the first-end ventilation module is set as an inclined surface parallel to the front end face of the adjacent middle ventilation module, and a connecting part is formed extending outward from the bottom side of the rear end face. A through groove communicating with the chamber is formed in the center of the bottom surface of the connecting part.

[0013] Furthermore, in each strain layer, the intermediate ventilation module is a block with a parallelogram-shaped top and bottom surface and an inverted trapezoidal radial cross-section, and a cavity opened from the bottom surface. The intermediate ventilation module has a cavity with a parallelogram-shaped top and bottom surface and an inverted trapezoidal radial cross-section opened from the bottom surface. The bottom sides of the front and rear ends of the intermediate ventilation module extend outward and form connecting parts for connecting with the ventilation modules located on the front and rear sides respectively. A through groove communicating with the cavity is opened in the center on the bottom surface of the connecting parts on both sides.

[0014] Furthermore, the chamber of the intermediate ventilation module and the rear chamber of the first ventilation module are identical in axial length and radial height, respectively.

[0015] Furthermore, in each strain layer, the rear ventilation module is a block with an inverted isosceles trapezoidal radial cross-section, and a chamber with the same inverted isosceles trapezoidal radial cross-section is formed from the front side of the bottom face; wherein, the front end face of the rear ventilation module is set as an inclined surface parallel to the front end face of the adjacent middle ventilation module, and a connecting part is formed from the bottom side of the front end face, and a through groove communicating with the chamber is formed in the center of the bottom surface of the connecting part.

[0016] Furthermore, the chamber of the rear ventilation module is identical to the rear chamber of the front ventilation module in both axial length and radial height.

[0017] Furthermore, the soft actuator for realizing omnidirectional bending and torsional motion in space also includes a control mechanism; the control mechanism includes four sets of air supply mechanisms connected to the air inlets of the four strain layers respectively; each set of air supply mechanisms consists of a first solenoid valve, a second solenoid valve, a tee connector, an air inlet pipeline, an air delivery pipeline, and an air venting pipeline; one end of the air inlet pipeline is used to connect to an external air source, and the other end is connected to the first interface of the tee connector to form a connection; one end of the air delivery pipeline is connected to the second interface of the tee connector to form a connection, and the other end is connected to the air inlet of the strain layer to form a connection; one end of the air venting pipeline is connected to the third interface of the tee connector to form a connection, and the other end is used to communicate with an external air source or the atmosphere; the first solenoid valve is installed on the air inlet pipeline, and the second solenoid valve is installed on the air venting pipeline; the control mechanism also includes a PLC controller, which is electrically connected to the first solenoid valve and the second solenoid valve of each set of air supply mechanisms respectively.

[0018] A motion driving method for a software actuator that realizes omnidirectional bending and torsional motion in space, characterized in that it includes:

[0019] I. By introducing air into the air chambers of any two adjacent strain layers, the soft actuator is caused to bend and deform in the corresponding direction; and / or,

[0020] II. By introducing air into the air chambers of any two opposing strain layers, the soft actuator is torsionally deformed in the corresponding direction.

[0021] Furthermore, in the above-mentioned action driving method, the gas pressure for venting the strain layer is 0 kPa to 40 kPa.

[0022] Compared with existing technologies, this soft actuator that realizes omnidirectional bending and twisting motion in space consists of an actuator and a control mechanism. The actuator has a strain layer consisting of four identical inclined air chambers, which enables four-way bending and two-way twisting. The control mechanism controls the gas pressure entering the four elastic air chambers, allowing the actuator to freely select the bending and twisting directions during operation, and enabling hovering and sweeping at any position within a certain area in space. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of one side structure of a soft actuator that realizes omnidirectional bending and torsional motion in an embodiment of the present invention;

[0024] Figure 2 for Figure 1 AA section view;

[0025] Figure 3 This is a schematic diagram of the structure of the first strain layer of the soft actuator that realizes omnidirectional bending and torsional motion in an embodiment of the present invention.

[0026] Figure 4 for Figure 3 BB section view;

[0027] Figure 5 This is a schematic diagram of the other side of the soft actuator that realizes omnidirectional bending and torsional motion in an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the inverted configuration of the intermediate ventilation module (without the front and rear connecting parts) of the soft actuator that realizes omnidirectional bending and torsional motion in space, according to an embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram of the control mechanism structure of a soft actuator that realizes omnidirectional bending and torsional motion in space, as shown in an embodiment of the present invention.

[0030] Figure 8 This is a schematic diagram showing the code markings of each strain layer in the software actuator that realizes omnidirectional bending and torsional motion in space during the simulation test of the present invention.

[0031] Figure 9 This is a schematic diagram of the bending state driven by individually supplying air to the air chambers of two adjacent strain layers during the simulation test of the soft actuator that realizes omnidirectional bending and torsional motion in space during the simulation test of the present invention.

[0032] Figure 10 This is a schematic diagram of the torsional state driven by individual air supply to the air chambers of two opposing strain layers during the simulation test of the soft actuator that realizes omnidirectional bending and torsional motion in space during the simulation test of the present invention.

[0033] Figure 11 This is a schematic diagram illustrating the bending and torsional state during the simulation test of the software actuator that realizes omnidirectional bending and torsional motion in space. The actuator is driven by supplying air to the air chambers of two adjacent strain layers while simultaneously supplying air to the air chamber of the third strain layer with adjusted pressure. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0035] See Figure 1 The soft actuator that realizes omnidirectional bending and torsional motion in space includes an actuator mechanism, which is specifically composed of a central layer 1, four limiting layers 2, two first strain layers 3 and two second strain layers 4; in this embodiment, all of the above components are made of silicone with a hardness of 0.5HA.

[0036] The central layer 1 is a strip-shaped cube with a square radial cross-section, serving as the base skeleton of the software actuator. In this embodiment, the radial cross-section of the central layer 1 is a cube with a side length of 8 mm and an axial length of 114 mm.

[0037] The limiting layer 2 is a sheet-like body with an isosceles trapezoidal radial cross-section, also made of silicone. The axial length of the limiting layer 2 is preferably the same as that of the central layer 1, and the width of its narrowest side is the same as the width of the sidewall of the central layer 1. The four limiting layers 2 are fixed to the four sidewalls of the central layer 1 by means of their narrowest side surfaces adhering to the wall surface of the central layer 1. The narrowest side surface of the limiting layer 2 is also the upper bottom surface of the limiting layer 2, corresponding to the plane where the upper bottom of the isosceles trapezoidal radial cross-section is located. Correspondingly, the side of the limiting layer 2 opposite to the narrowest side surface is the widest side surface of the limiting layer 2.

[0038] In this embodiment, the radial cross section of the limiting layer 2 is an isosceles trapezoid with an upper base of 8mm, a lower base of 10mm, and a height of 2mm, and the axial length of the limiting layer 2 is 114mm; the narrow side surface of the four limiting layers 2 is bonded to the four side walls of the central layer 1 with liquid silicone.

[0039] See Figure 1 and Figure 5 The first strain layer 3 is a strip of silicone body with an isosceles trapezoidal radial cross section. It is formed by connecting and integrally molding a head ventilation module I, seven intermediate ventilation modules II and a tail ventilation module III arranged in a straight line from front to back at equal intervals. An oblique through groove 10 is formed between each two adjacent ventilation modules, which runs through the width of the strain layer. The angle α between the direction of the oblique through groove 10 and the axial direction of the strain layer is 60°. Each ventilation module has a chamber, and the chambers between adjacent ventilation modules are connected, so that an air chamber is formed in the first strain layer 3.

[0040] The second strain layer 4 has the same structure as the first strain layer 3. It is also formed by connecting and integrally molding a front-end ventilation module I, seven intermediate ventilation modules II and a rear-end ventilation module III arranged in a straight line with equal spacing from front to back. An oblique through-slot 10 is formed between each two adjacent ventilation modules, which runs through the width of the strain layer. The angle α between the direction of the oblique through-slot 10 and the axial direction of the strain layer is 60°. Each ventilation module has a chamber, and the chambers between adjacent ventilation modules are connected, so that an air chamber is formed in the second strain layer 4. However, unlike the first strain layer 3, the oblique direction of the oblique through-slot 10 on the second strain layer 4 is opposite to that on the first strain layer 3, so that the second strain layer 4 and the first strain layer 3 have a mirror symmetrical structure.

[0041] Two first strain layers 3 are fixed to the restricting layer 2 located on a set of opposite sidewalls of the central layer 1 by means of their small-sized surface being attached to the large-width side surface of the restricting layer 2. Similarly, two second strain layers 4 are fixed to the restricting layer 2 located on another set of opposite sidewalls of the central layer 1 by means of their small-sized surface being attached to the large-width side surface of the restricting layer 2. Furthermore, since the oblique through-slots 10 on the adjacent first strain layers 3 and second strain layers 4 are arranged in opposite directions, they not only have the structural characteristics of bending deformation, but also the structural characteristics of torsional deformation.

[0042] The following section uses the first strain layer 3 as an example to describe the specific structure of the strain layer in detail.

[0043] The first strain layer 3's initial ventilation module I is a block with an inverted isosceles trapezoidal radial cross-section, and a chamber 6 with the same inverted isosceles trapezoidal radial cross-section is formed from its bottom surface. A ventilation hole communicating with the chamber 6 is formed axially from the front end face of the initial ventilation module I. To facilitate communication with an external air source, a connection end 5 communicating with the ventilation hole is provided on its front end face. In practical applications, the strain layer connects to an external air source via a pipeline through the connection end at its front end, thereby pumping gas into the initial ventilation module. The chamber 6 of the initial ventilation module I consists of a front chamber and a rear chamber that are connected. The axial length of the front chamber is greater than that of the rear chamber. The length and radial height of the front chamber are greater than the radial height of the rear chamber, so that the gas pressure initially entering the strain layer is buffered by the front chamber before entering the rear chamber. In addition, the rear end face of the front ventilation module I is set as a slope, the angle between the slope and the axial direction of the strain layer is 60°, and a connecting part is formed from the bottom side of the rear end face to connect with the intermediate ventilation module II located on the adjacent side, forming a sloping through groove 10. A through groove 9 communicating with the chamber is provided in the center of the bottom surface of the connecting part, so that when the front ventilation module I and the intermediate ventilation module II located on its rear side are connected, the chambers 6 of the two are connected through the through groove 9 on the connecting part.

[0044] See Figure 6The intermediate ventilation module II of the first strain layer 3 is a block with a parallelogram-shaped top and bottom surface and an inverted trapezoidal radial cross-section. A chamber is formed on the bottom surface of the block. A chamber 6 with a parallelogram-shaped top and bottom surface and an inverted trapezoidal radial cross-section is formed on the bottom surface of the intermediate ventilation module II. Preferably, the chamber of the intermediate ventilation module II has the same axial length and radial height as the rear chamber of the first ventilation module. The bottom sides of the front and rear ends of the intermediate ventilation module II extend outward and form connecting parts for connecting with the ventilation modules located on the front and rear sides respectively. A through groove 9 communicating with the chamber is formed in the center on the bottom surface of the connecting parts on both sides, so that when connected with the ventilation modules located on the front and rear sides, the chambers 6 of the two are connected through the through groove 9 on the connecting parts.

[0045] The rear ventilation module III of the first strain layer 3 is a block with an inverted isosceles trapezoidal radial cross-section. A chamber 6 with the same inverted isosceles trapezoidal radial cross-section is formed on the front side of the bottom face, so that the chamber of the rear ventilation module III is located on the front side of the module. Preferably, the chamber 6 of the rear ventilation module III has the same axial length and radial height as the rear chamber of the front ventilation module. In addition, the front end face of the rear ventilation module III is set as an inclined surface, which forms an angle of 60° with the axial direction of the strain layer. It extends outward from the bottom side of the front end face and forms a connecting part for connecting with the intermediate ventilation module II located on the adjacent side, forming an inclined through groove 10. A through groove 9 communicating with the chamber is formed in the center on the bottom surface of the connecting part, so that when the rear ventilation module III and the intermediate ventilation module II located on its front side are connected, the chambers 6 of the two are connected through the through groove 9 on the connecting part.

[0046] As described above, adjacent first-end ventilation modules and intermediate ventilation modules, two adjacent intermediate ventilation modules, and adjacent intermediate ventilation modules and tail-end ventilation modules are all connected by two adjacent connecting parts on their bottom sides, forming an oblique through groove 10 between two adjacent ventilation modules, i.e., leaving a deformation gap; a groove for connecting the chambers of the two ventilation modules is provided in the center of the bottom surface of the connecting part between each pair of adjacent ventilation modules, so that the chambers of each ventilation module are connected sequentially from front to back, so that the gas entering the chamber of the first-end ventilation module gradually flows to the other chambers behind.

[0047] See Figure 5In this embodiment, the axial length of both the first strain layer 3 and the second strain layer 4 is 114 mm. The width of the outer side of both is 20 mm, and the thickness in the radial direction is 10 mm. The width of the inner side is also 10 mm, ensuring that they completely cover the wider side of the limiting layer when bonded and fixed to it. Among the strain layers, the maximum axial side length a of the first-end ventilation module I is 29.35 mm, the side length b of the outer-side block surface in the strain layer width direction is 20 mm, and the thickness c in the radial direction is 10 mm. In the middle ventilation module II, the outer-side block surface has an axial side length d of 8 mm. The side length e in the width direction of the variable layer is 20mm, and the thickness c in the radial direction is 10mm; the axial side length f of the tail ventilation module III is 24.11mm, the side length g of the outer block surface in the strain layer width direction is 20mm, and the thickness c in the radial direction is 10mm; the groove width h of the oblique through groove 10 between adjacent ventilation modules is 2mm; the chambers opened in the front ventilation module and the middle ventilation module are centrally located, wherein the chamber of the front ventilation module has an axial length of 22.53mm, the chamber of the tail ventilation module has an axial length of 11.81mm, and the chamber wall thickness of the middle ventilation module is 2mm.

[0048] In this embodiment, the specific fabrication steps of the soft actuator are as follows: 1) a mold is prepared by 3D printing using resin material; 2) the mold is cleaned and petroleum jelly is evenly applied inside the mold; 3) a large strain layer, an upper adhesive layer, and a lower adhesive layer are prepared by casting; 4) a small strain layer in the middle is cut, which is slightly smaller than the upper adhesive layer; 5) the large strain layer, the upper adhesive layer, the small strain layer in the middle, and the lower adhesive layer are sequentially bonded and sealed using uncured liquid silicone to prepare a soft actuator that realizes omnidirectional bending and torsional motion in space.

[0049] See Figure 7The soft actuator that enables omnidirectional bending and torsional motion in space also includes a control mechanism. Specifically, the control mechanism includes four sets of air supply mechanisms, each connected to the air inlet 5 of one of the four strain layers, to independently control the air supply status of each strain layer. Each air supply mechanism consists of a first solenoid valve 7, a second solenoid valve 8, a three-way connector 11, an air inlet pipeline 12, an air delivery pipeline 13, and an air outlet pipeline 14. One end of the air inlet pipeline 12 is connected to the outlet of an external air source (such as a high-pressure gas tank), and the other end is connected to the first interface (i.e., L1 end) of the three-way connector 11 to form a connection. One end of the air delivery pipeline 13 is connected to the second interface (i.e., L2 end) of the three-way connector 11. One end of the venting line 14 is connected to the third interface (i.e., L3 end) of the three-way connector 11, and the other end is used to connect to the air inlet of an external air source (or directly to the atmosphere); the first solenoid valve 7 is installed on the air inlet line 12 to control the opening / closing of the air inlet line 12; the second solenoid valve 8 is installed on the venting line 14 to control the opening / closing of the venting line 14; the control mechanism also includes a PLC controller, which is electrically connected to the first solenoid valve 7 and the second solenoid valve 8 of each air supply mechanism to control the opening and closing states of the first solenoid valve 7 and the second solenoid valve 8.

[0050] In use, the working principle of this control mechanism is as follows: the PLC controller controls the opening and closing states of the first solenoid valve 7 and the second solenoid valve 8 in each air supply mechanism to supply air to the specified strain layer of the external air source box, thereby controlling the soft actuator to perform bending and / or torsional deformation in the specified direction according to the Euler spiral shape; after the soft actuator completes the action, by closing all the first solenoid valves 7 and opening all the second solenoid valves 8, the soft actuator is restored to its initial shape.

[0051] Furthermore, to demonstrate that the aforementioned soft actuator capable of omnidirectional bending and torsional motion can perform bending and torsional movements in any direction, finite element analysis was used to simulate and test the bending and torsional movements performed by the actuator under different air supply conditions. See [link to relevant documentation]. Figure 8 To facilitate the description of the gas supply conditions of different strain layers, each strain layer in the soft actuator that realizes omnidirectional bending and torsional motion in this embodiment is marked with a code.

[0052] Test 1:

[0053] In this embodiment, air is supplied to the air chambers of each pair of adjacent strain layers of the soft actuator that realizes omnidirectional bending and torsional motion, while the air chambers of the other two strain layers are not supplied with air. The bending deformation of the soft actuator is observed. In this simulation test, the air supply pressure is set to 30 kPa of compressed air.

[0054] like Figure 9Figure (a) shows a schematic diagram of the bending deformation of a soft actuator when gas is supplied to the gas chambers of strain layers A and B alone, but not to strain layers C and D; Figure 9 Figure (b) shows a schematic diagram of the bending deformation of the soft actuator when gas is supplied only to the gas chambers of strain layers B and C, and not to strain layers A and D; Figure 9 Figure (c) shows a schematic diagram of the bending deformation of the soft actuator when gas is supplied only to the gas chambers of strain layers C and D, and not to strain layers A and B; Figure 9 Figure (d) shows a schematic diagram of the bending deformation of the soft actuator when gas is supplied to the gas chambers of strain layer D and strain layer A alone, and when gas is not supplied to strain layer B and strain layer C. The above four schematic diagrams of the bending deformation of the soft actuator illustrate that by supplying gas to the gas chambers of two adjacent strain layers, the soft actuator can be driven to bend in a specified direction.

[0055] Test 2:

[0056] In this embodiment, the air chambers of each pair of opposite strain layers in the soft actuator that realizes omnidirectional bending and torsional motion are individually supplied with air, while the air chambers of the other two strain layers are not supplied with air. The bending deformation of the soft actuator is observed. In this simulation test, the air supply pressure is set to 30 kPa compressed air.

[0057] like Figure 10 Figure (a) shows a schematic diagram of the bending deformation of a soft actuator when gas is supplied only to the gas chambers of strain layers A and C, and not to strain layers B and D; Figure 10 Figure (b) shows a schematic diagram of the bending deformation of the soft actuator when gas is supplied to the gas chambers of strain layer B and strain layer D alone, and when gas is not supplied to strain layer A and strain layer C. The two schematic diagrams of the bending deformation of the soft actuator illustrate that by supplying gas to the gas chambers of the two opposite strain layers, the soft actuator can be driven to undergo torsional deformation in two opposite directions.

[0058] Test 3:

[0059] In this embodiment, air is supplied to the air chambers of two adjacent strain layers in the soft actuator that realizes omnidirectional bending and torsional motion in space, and variable pressure air is supplied to the air chamber of another strain layer. In this simulation test, the air pressure supplied to the air chambers of strain layers A and B is set to 30 kPa, and the air pressure supplied to the air chamber of strain layer C gradually increases from 0 kPa to 15 kPa, 20 kPa, 25 kPa, 30 kPa and 35 kPa. No air is supplied to strain layer D. The bending deformation of the soft actuator is observed.

[0060] like Figure 11As shown, when a constant pressure is maintained in the air supply to the strain layer A and strain layer B of the soft actuator that realizes omnidirectional bending and torsional motion in space, while the air supply pressure to the air chamber of strain layer C is gradually increased, it can be seen that while the soft actuator undergoes bending deformation, it can also be driven to perform torsional movements of different degrees by utilizing the different air supply pressures.

[0061] In summary, the soft actuator of the present invention, which realizes omnidirectional bending and twisting motion, can perform bending motion in any of the four directions and twisting motion in two directions by providing different air supply conditions. Furthermore, by combining bending and twisting motions, the soft actuator can bend and twist in any direction, thereby achieving a wider range of motion execution.

Claims

1. A soft actuator for realizing omnidirectional bending and torsional motion in space, characterized in that, The device includes an actuator, which consists of a central layer (1), four confinement layers (2), two first strain layers (3), and two second strain layers (4). The central layer (1) is a strip-shaped cube with a square radial cross-section; the confinement layers (2) are sheet-like bodies with an isosceles trapezoidal radial cross-section; the four confinement layers (2) are fixed to the four side walls of the central layer (1) by adhering to one side of the central layer (1) with their narrowest side surface; the first strain layer (3) is a strip-like body with an isosceles trapezoidal radial cross-section. The first strain layer (3) is formed by sequentially connecting and integrally molding a front-end ventilation module, multiple intermediate ventilation modules, and a rear-end ventilation module arranged in a straight line with equal spacing from front to back. An oblique through-slot is formed between each pair of adjacent ventilation modules, extending along the width of the strain layer. Each ventilation module contains a chamber, and the chambers of adjacent ventilation modules are interconnected, forming an air chamber within the first strain layer (3). The second strain layer (4) has the same structure as the first strain layer (3) and is mirror-symmetrical to it. A strain layer (3) is fixed to the confinement layer (2) located on a set of opposite sidewalls of the central layer (1) by means of its small-sized surface being attached to the large-width side surface of the confinement layer (2). Two second strain layers (4) are fixed to the confinement layer (2) located on another set of opposite sidewalls of the central layer (1) by means of their small-sized surface being attached to the large-width side surface of the confinement layer (2). The central layer (1), the confinement layer (2), the first strain layer (3), and the second strain layer (4) are all made of elastic material. The ventilation module is a block with an inverted isosceles trapezoidal radial cross-section, and a chamber with the same inverted isosceles trapezoidal radial cross-section is opened from its bottom surface; the intermediate ventilation module is a block with a parallelogram-shaped top and bottom surface and an inverted trapezoidal radial cross-section, and a chamber with the same inverted isosceles trapezoidal radial cross-section is opened from its bottom front surface; the rear ventilation module is a block with an inverted isosceles trapezoidal radial cross-section, and a chamber with the same inverted isosceles trapezoidal radial cross-section is opened from its bottom front front surface.

2. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, The axial length of the confinement layer (2) is the same as that of the central layer (1). The width of the layer on its narrow side is the same as that of the sidewall of the central layer (1). The angle between the layer on its wide side and the adjacent inclined surface is 50°~80°. The thickness of the confinement layer (2) is 1mm~3mm.

3. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, In each strain layer, the angle α between the direction of the inclined through groove and the axial direction of the strain layer is 50° ~ 80°.

4. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, Each strain layer has a connecting end (5) on the front end face of the first end ventilation module, and the inner cavity of the connecting end (5) is connected to the air chamber of the strain layer.

5. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, In each strain layer, the width of the oblique through-slot formed between adjacent ventilation modules is 1mm~3mm.

6. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, The chamber of the first-end ventilation module consists of a front chamber and a rear chamber that are connected to each other. The front chamber is connected to the front end face of the first-end ventilation module through a vent hole. The axial length of the front chamber is greater than the axial length of the rear chamber, and the radial height is greater than the radial height of the rear chamber. The rear end face of the first-end ventilation module is set as an inclined surface parallel to the front end face of the adjacent middle ventilation module. It extends outward from the bottom side of the rear end face and forms a connecting part. A through groove communicating with the chamber is opened in the center on the bottom surface of the connecting part.

7. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, The front and rear bottom sides of the intermediate ventilation module extend outward and form connecting parts for connecting with the ventilation modules located on the front and rear sides respectively; a through groove communicating with the chamber is provided in the center on the bottom surface of the connecting parts on both sides.

8. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, The front end face of the rear ventilation module is set as an inclined surface parallel to the front end face of the adjacent middle ventilation module, and a connecting part is formed extending outward from the bottom side of the front end face. A through groove communicating with the chamber is provided in the center of the bottom surface of the connecting part.

9. The soft actuator for realizing omnidirectional bending and torsional motion in space according to claim 1, characterized in that, It also includes a control mechanism; the control mechanism includes four sets of gas supply mechanisms connected to the gas inlet ends of the four strain layers respectively; each set of gas supply mechanisms consists of a first solenoid valve, a second solenoid valve, a tee connector, an inlet pipeline, a delivery pipeline, and a venting pipeline; one end of the inlet pipeline is used to connect to an external gas source, and the other end is connected to the first interface of the tee connector to form a connection; one end of the delivery pipeline is connected to the second interface of the tee connector to form a connection, and the other end is connected to the gas inlet end of the strain layer to form a connection; one end of the venting pipeline is connected to the third interface of the tee connector to form a connection, and the other end is used to communicate with an external gas source or the atmosphere; the first solenoid valve is installed on the inlet pipeline, and the second solenoid valve is installed on the venting pipeline; the control mechanism also includes a PLC controller, which is electrically connected to the first solenoid valve and the second solenoid valve of each set of gas supply mechanisms respectively.

10. A motion driving method for a soft actuator that realizes omnidirectional bending and torsional motion in space as described in any one of claims 1 to 9, characterized in that, include: I. By introducing air into the air chambers of any two adjacent strain layers, the soft actuator is caused to bend and deform in the corresponding direction; And / or, II. By introducing air into the air chambers of any two opposing strain layers, the soft actuator is torsionally deformed in the corresponding direction.

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