Soft body actuator for realizing spatial omnidirectional bending and twisting motion and driving method of soft body actuator

Abstract

The invention discloses a software actuator for realizing spatial omnidirectional bending and twisting motion and a driving method of the software actuator. The software actuator comprises a central layer, four limiting layers, two first strain layers and two second strain layers, the central layer is a strip-shaped body with a square radial section; the four limiting layers are respectively attached and fixed on the four side wall surfaces of the central layer; the first strain layer and the second strain layer are of a mirror symmetry structure and are each formed by connecting a head end ventilation module, a plurality of middle ventilation modules and a tail end ventilation module which are linearly arranged at equal intervals from front to back, and an inclined through groove is formed between every two adjacent ventilation modules. Each ventilation module is internally provided with a cavity, and the cavities between the adjacent ventilation modules are communicated to form an air chamber; the four strain layers are alternately arranged and fixedly attached to the four limiting layers; the soft actuator can freely select the bending direction and the twisting direction through pneumatic driving, and hovering and sweeping at any position in a certain area in space are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of soft robots, and in particular to a soft actuator capable of realizing omnidirectional bending and twisting motion in space. Background Art

[0002] Compared with traditional robots, soft robots are soft and deformable, and have better adaptability, flexibility and safety. The soft structure of soft robots enables them to adapt to various irregular shapes and surfaces, so that they can traverse and perform tasks in complex environments. In addition, soft robots use soft materials that can resist collisions and deformations, and have higher toughness and durability. As an important component of soft robots, elastic actuators were first introduced into soft robot design by Correll N et al. with rib structures, but their structure limited the bending performance of elastic actuators. Later, Mosadegh B et al. proposed an elastic brake with a fast air mesh structure to improve the bending performance of elastic actuators. Wang T et al. also adjusted the angle of the soft actuator to produce coupled motion of bending and torsion, but the deformation that a single soft actuator can produce is limited, and can only achieve deformation in a single direction. Summary of the invention

[0003] The purpose of the present invention is to provide a soft actuator that can solve the above-mentioned technical problems and realize omnidirectional bending and torsional motion in space.

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

[0005] To this end, the technical solution of the present invention is as follows:

[0006] A soft actuator for realizing omnidirectional bending and twisting motion in space, comprising an actuator, which is composed of a central layer, four restriction layers, two first strain layers and two second strain layers; wherein the central layer is a strip-shaped cube with a square radial cross section; the restriction layer is a sheet-shaped body with an isosceles trapezoidal radial cross section; the four restriction layers are respectively fixed on the four side wall surfaces of the central layer in a manner that the side surfaces of the four restriction layers with a small width are fitted with the wall surface of the central layer; the first strain layer is a strip-shaped body with an isosceles trapezoidal radial cross section, which is composed of a head end ventilation module, a plurality of middle ventilation modules and a tail end ventilation module arranged in a straight line with equal spacing from front to back, which are connected in sequence and integrally formed, and a space is formed between each two adjacent ventilation modules. An oblique through groove runs through the width direction of the strain layer; a chamber is opened in each ventilation module, and the chambers between adjacent ventilation modules are connected, so that an air chamber is formed in the first strain layer; the second strain layer has the same structural composition as the first strain layer, and is mirror-symmetrical with the first strain layer; the two first strain layers are fixed on the restriction layer located on one group of opposite side walls of the central layer in a manner that their small-sized layers are fitted with the large-width side layers of the restriction layer, and the two second strain layers are fixed on the restriction layer located on another group of opposite side walls of the central layer in a manner that their small-sized layers are fitted with the large-width side layers of the restriction layer; the central layer, the restriction layer, the first strain layer and the 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 limiting layer is the same as that of the central layer, the width of the layer on the side with a smaller width is the same as the side wall width of the central layer 1, and the angle between the layer on the side with a larger width and its adjacent inclined surface is 50° to 80°; the layer thickness of the limiting layer is 1mm to 3mm.

[0009] Furthermore, in each strain layer, an angle α formed between the arrangement direction of the oblique through grooves and the axial direction of the strain layer is 50° to 80°.

[0010] Furthermore, a connecting end is provided on the front end surface of the ventilation module at the head end of each strain layer, and the inner cavity of the connecting end is communicated with the air chamber of the strain layer.

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

[0012] Furthermore, in each strain layer, the head-end ventilation module is a block with a radial cross-section of an inverted isosceles trapezoid, and a chamber with the same radial cross-section of an inverted isosceles trapezoid is opened from the bottom surface; wherein, the chamber of the head-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 head-end ventilation module through a vent, and 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 head-end ventilation module is set as an inclined surface parallel to the front end face of the adjacent middle ventilation module, and extends outward from the bottom side of the rear end face to form a connecting portion, and a through groove connected to the chamber is centrally opened on the bottom surface of the connecting portion.

[0013] Furthermore, in each strain layer, the middle ventilation module is a block whose top and bottom surfaces are both parallelograms and whose radial cross-section is an inverted trapezoid, and whose bottom surface is provided with a chamber, and whose top and bottom surfaces are also parallelograms and whose radial cross-section is an inverted trapezoid, and whose bottom surface is provided with a chamber; wherein the bottom sides of the front and rear ends of the middle ventilation module extend outwards respectively and form connecting parts for connecting with the adjacent ventilation modules on the front and rear sides respectively; and through grooves communicating with the chamber are centrally provided on the bottom surfaces of the connecting parts on both sides.

[0014] Further, the chamber of the middle ventilation module and the rear chamber of the head-end ventilation module are respectively identical in axial length and radial height.

[0015] Furthermore, in each strain layer, the rear-end ventilation module is a block with a radial cross-section of an inverted isosceles trapezoid, and a chamber with the same radial cross-section of an inverted isosceles trapezoid is opened from the front side of the bottom surface; wherein, the front end face of the rear-end ventilation module is set as an inclined surface parallel to the front end face of the adjacent middle ventilation module, and extends outward from the bottom side of the front end face to form a connecting portion, and a through groove connected to the chamber is centrally opened on the bottom surface of the connecting portion.

[0016] Furthermore, the chamber of the rear end ventilation module and the rear chamber of the head end ventilation module are respectively identical in axial length and radial height.

[0017] Furthermore, the soft actuator that realizes omnidirectional bending and torsion movement in space also includes a control mechanism; the control mechanism includes four sets of air supply mechanisms respectively connected to the air inlet ends of the four strain layers; each set of air supply mechanisms is composed of a first solenoid valve, a second solenoid valve, a three-way joint, an air intake pipeline, an air supply pipeline and an air release pipeline; one end of the air intake pipeline is used to connect to an external air source, and the other end is connected to the first interface of the three-way joint to form a connection, one end of the air supply pipeline is connected to the second interface of the three-way joint to form a connection, and the other end is connected to the air intake end of the strain layer to form a connection, one end of the air release pipeline is connected to the third interface of the three-way joint 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 arranged on the air intake pipeline, and the second solenoid valve is arranged on the air release 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 method for driving a soft actuator for realizing omnidirectional bending and twisting motion in space is characterized by comprising:

[0019] I. by ventilating the air chambers of any two adjacent strain layers, the soft actuator is bent and deformed in the corresponding direction; and / or,

[0020] II. By ventilating the air chambers of any two opposite strain layers, the soft actuator is twisted and deformed in the corresponding direction.

[0021] Furthermore, in the above-mentioned motion driving method, the pressure of the gas ventilated to the strain layer is 0 KPa to 40 KPa.

[0022] Compared with the existing technology, the soft actuator that realizes omnidirectional bending and torsion motion in space is composed of an actuator and a control mechanism. The actuator has a strain layer composed of four identical inclined air chambers, which can realize four-way bending and two-way torsion. The control mechanism controls the gas pressure entering the four elastic air chambers, so that the actuator can freely choose the bending direction and torsion direction in the working state, and can realize hovering and sweeping at any position within a certain area in space. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of one side of a soft actuator for realizing omnidirectional bending and twisting motion in space in an embodiment of the present invention;

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

[0025] Figure 3 It is a schematic structural diagram of the first strain layer of a soft actuator for realizing omnidirectional bending and twisting motion in space in an embodiment of the present invention;

[0026] Figure 4 for Figure 3 BB cross-sectional view;

[0027] Figure 5 It is a schematic diagram of the structure of the other side of the soft actuator for realizing omnidirectional bending and twisting motion in space in an embodiment of the present invention;

[0028] Figure 6 It is a structural schematic diagram of an inverted setting state of a middle ventilation module (the front and rear connecting parts are omitted) of a soft actuator for realizing omnidirectional bending and twisting motion in space in an embodiment of the present invention;

[0029] Figure 7 A schematic diagram of the control mechanism structure of a software actuator that realizes omnidirectional bending and twisting motion in space in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the code marking of each strain layer in the soft actuator that realizes omnidirectional bending and torsion motion in space in the simulation test of the present invention;

[0031] Fig. 9 It is a schematic diagram of the bending state of performing separate air supply drive to the air chambers of two adjacent strain layers during the simulation test of the soft actuator that realizes omnidirectional bending and torsion motion in space in the simulation test of the present invention;

[0032] Fig.10 It is a schematic diagram of the torsion state of performing separate air supply drive to the air chambers of two relative strain layers when performing a simulation test on the soft actuator that realizes omnidirectional bending and torsion motion in space in the simulation test of the present invention;

[0033] Fig.11 This is a schematic diagram of the bending and torsion state of supplying air to the air chambers of two adjacent strain layers while regulating the pressure of the air chamber of the third strain layer to supply air to the air chamber when performing a simulation test on a soft actuator that realizes omnidirectional bending and torsion motion in space in the simulation test of the present invention. DETAILED DESCRIPTION

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

[0035] See also Figure 1 The soft actuator for realizing omnidirectional bending and torsion motion in space includes an actuator, which is specifically composed of a central layer 1, four restriction layers 2, two first strain layers 3 and two second strain layers 4; in this embodiment, the above-mentioned components are all 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, which serves as the base skeleton of the soft 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 restriction layer 2 is a sheet-like body with a radial cross-section of an isosceles trapezoid, which is also made of silicone; the axial length of the restriction layer 2 is preferably the same as the axial length of the central layer 1, and the width of its small-width side layer is the same as the side wall width of the central layer 1; the four restriction layers 2 are respectively fixed on the four side wall surfaces of the central layer 1 in a manner that the small-width side layers thereof are in contact with the wall surface of the central layer 1; wherein, the small-width side layer of the restriction layer 2, that is, the upper bottom surface of the restriction layer 2, corresponds to the plane where the upper bottom of the isosceles trapezoid of its radial cross-section is located; accordingly, the side of the restriction layer 2 opposite to the small-width side layer is the large-width side layer of the restriction layer 2.

[0038] In this embodiment, the radial cross-section of the restriction layer 2 is an isosceles trapezoid with an upper base of 8 mm, a lower base of 10 mm, and a height of 2 mm, and the axial length of the restriction layer 2 is 114 mm; the small width side surfaces of the four restriction layers 2 are respectively bonded to the four side wall surfaces of the center layer 1 using liquid silicone.

[0039] See also Figure 1 and Figure 5 The first strain layer 3 is a strip of silicone with an isosceles trapezoidal radial cross section, which is composed of a head ventilation module I, seven middle ventilation modules II and a tail ventilation module III arranged in a straight line with equal spacing from front to back, which are connected in sequence and integrally formed; an oblique through groove 10 that passes through the width direction of the strain layer is formed between each two adjacent ventilation modules, and the angle α formed between the setting direction of the oblique through groove 10 and the axial direction of the strain layer is 60°; a chamber is opened in each ventilation module, 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, and is also composed of a head ventilation module I, seven middle ventilation modules II and a tail ventilation module III arranged in a straight line with equal spacing from front to back, which are connected in sequence and integrally formed, and an oblique through groove 10 penetrating in the width direction of the strain layer is formed between every two adjacent ventilation modules, and the angle α formed between the setting direction of the oblique through groove 10 and the axial direction of the strain layer is 60°; each ventilation module is provided with 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, the difference from the first strain layer 3 is that the oblique direction of the oblique through groove 10 on the second strain layer 4 is opposite to the oblique direction of the oblique through groove 10 on the first strain layer 3, so that the second strain layer 4 and the first strain layer 3 are in a mirror-symmetrical structure.

[0041] The two first strain layers 3 are fixed on the restriction layer 2 located on one set of opposite side walls of the central layer 1 in a manner that their small-sized layers are in contact with the layers on one side with a larger width of the restriction layer 2. Similarly, the two second strain layers 4 are fixed on the restriction layer 2 located on another set of opposite side walls of the central layer 1 in a manner that their small-sized layers are in contact with the layers on one side with a larger width of the restriction layer 2. Furthermore, since the oblique through grooves 10 on the adjacent first strain layers 3 and second strain layers 4 are arranged in opposite directions, the two layers not only have the structural characteristics of bending deformation, but also have the structural characteristics of torsional deformation.

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

[0043] The head-end ventilation module I of the first strain layer 3 is a block with a radial cross-section of an inverted isosceles trapezoid, and a chamber 6 with the same radial cross-section of an inverted isosceles trapezoid is opened from the bottom surface; wherein, a ventilation hole connected to its chamber 6 is opened axially from the front end face of the head-end ventilation module I, and in order to facilitate communication with an external air source, a connecting end 5 that passes through the ventilation hole is provided on the front end face, so that in actual application, the strain layer is connected to the external air source through a pipeline via the connecting end arranged at its front end, thereby pumping gas into the head-end ventilation module; the chamber 6 of the head-end ventilation module I is composed of a front chamber and a rear chamber that are connected to each other, and the axial length of the front chamber is greater than the axial length of the rear chamber. The length and the height in the radial direction are greater than the height in the radial direction of the rear chamber, so that the front chamber buffers the gas pressure initially entering the strain layer before entering the rear chamber; in addition, the rear end face of the head-end ventilation module I is set as an inclined surface, and the angle formed between the inclined surface and the axial direction of the strain layer is 60°, and it extends outward from the bottom side of the rear end face and forms a connecting portion, which is used to connect with the intermediate ventilation module II located on the adjacent side and form an oblique through groove 10; a through groove 9 connected to the chamber is centrally opened on the bottom surface of the connecting portion, so that when the head-end ventilation module I is connected to the intermediate ventilation module II located on its rear side, the chambers 6 of the two are connected through the through groove 9 on the connecting portion of the two.

[0044] See also Figure 6The intermediate ventilation module II of the first strain layer 3 is a block with a top surface and a bottom surface both being parallelograms and a radial cross-section being an inverted trapezoid, and a chamber is opened from the bottom surface, and a chamber 6 is opened from the bottom surface, which is also a parallelogram on the top surface and the bottom surface and an inverted trapezoid on the radial cross-section; wherein, the chamber of the intermediate ventilation module II is preferably the same as the rear chamber of the head end ventilation module in axial length and radial height; the bottom sides of the front end and the rear end of the intermediate ventilation module II extend outward respectively and form connecting parts, which are used to connect with the adjacent ventilation modules located on the front and rear sides respectively; on the bottom surfaces of the connecting parts on both sides, a through groove 9 connected to the chamber is opened in the center, so that when connecting with the ventilation modules located on the front and rear sides thereof, the chambers 6 of the two are connected through the through groove 9 on the connecting parts of the two.

[0045] The rear ventilation module III of the first strain layer 3 is a block with a radial cross section of an inverted isosceles trapezoid, and a chamber 6 with a radial cross section of an inverted isosceles trapezoid is opened from the front side of the bottom surface, so that the chamber of the rear ventilation module III is located on the front side of the module; wherein, the chamber 6 of the rear ventilation module III is preferably the same as the rear chamber of the head ventilation module in axial length and radial height respectively; in addition, the front end face of the rear ventilation module III is set as an inclined surface, and the angle between the inclined surface and the axial direction of the strain layer is 60°, and it extends outward from the bottom side of the front end face and forms a connecting portion, which is used to connect with the intermediate ventilation module II located on the adjacent side and form an oblique through groove 10; a through groove 9 connected to the chamber is opened in the center on the bottom surface of the connecting portion, so that when the rear ventilation module III is connected to the intermediate ventilation module II located on its front side, the chambers 6 of the two are connected through the through groove 9 on the connecting portion of the two.

[0046] As described in the above structure, the adjacent head-end ventilation modules and the middle ventilation modules, the adjacent two middle ventilation modules, and the adjacent middle ventilation modules and the tail-end ventilation modules are connected by two adjacent connecting parts on their bottom sides, so that an oblique through groove 10 is formed between the two adjacent ventilation modules, that is, a deformation gap is left; a groove for connecting the two ventilation module chambers is centrally provided on the bottom surface of the connecting part between each two adjacent ventilation modules, so that the chambers of each ventilation module are connected in sequence from front to back, so that the gas entering the chamber of the head-end ventilation module gradually flows to other chambers at the back.

[0047] See also Figure 5In this embodiment, the axial length of the first strain layer 3 and the second strain layer 4 is 114 mm, the width of the layer on the outward side is 20 mm, the thickness in the radial direction is 10 mm, and the width of the layer on the inward side is 10 mm, so that when they are attached and fixed to the restriction layer, they completely cover the layer on the wide side of the restriction layer; wherein, in each strain layer, the maximum axial side length a of the head end ventilation module I is 29.35 mm, the side length b of the block surface on the outward side in the direction of the strain layer width is 20 mm, and the thickness c in the radial direction is 10 mm; in the middle ventilation module II, the block surface on the outward side is 8 mm in the axial direction, and the thickness c in the radial direction is 10 mm. The side length e in the width direction of the strain layer is 20 mm, and the thickness c in the radial direction is 10 mm; the axial side length f of the tail ventilation module III is 24.11 mm, the side length of the block surface on the outward side in the direction of the strain layer width g is 20 mm, and the thickness c in the radial direction is 10 mm; the groove width h of the oblique through groove 10 between adjacent ventilation modules is 2 mm; the chambers opened in the front ventilation module and the middle ventilation module are centrally arranged, wherein the length of the chamber of the front ventilation module in the axial direction is 22.53 mm, the length of the chamber of the tail ventilation module in the axial direction is 11.81 mm, and the wall thickness of the chamber of the middle ventilation module is 2 mm.

[0048] In this embodiment, the specific preparation steps of the soft actuator are: 1) using resin material to prepare a mold by 3D printing; 2) cleaning the mold and evenly applying vaseline inside the mold; 3) using casting molding to prepare a large strain layer, an upper bonding layer and a lower bonding layer; 4) cutting a middle small strain layer slightly smaller than the upper bonding layer; 5) using unsolidified liquid silicone to sequentially bond and seal the large strain layer, the upper bonding layer, the middle small strain layer and the lower bonding layer to prepare a soft actuator that can realize omnidirectional bending and torsional motion in space.

[0049] See also Figure 7The soft actuator for realizing omnidirectional bending and torsion motion in space also includes a control mechanism; specifically, the control mechanism includes four sets of air supply mechanisms, which are respectively connected to the air inlet ends 5 of the four strain layers to realize the independent control of the air supply state of each strain layer; wherein each set of air supply mechanisms is composed of a first solenoid valve 7, a second solenoid valve 8, a three-way joint 11, an air inlet pipeline 12, an air delivery pipeline 13 and an air release pipeline 14; one end of the air inlet pipeline 12 is used to be connected to the air outlet end of an external air source (such as a high-pressure gas tank), and the other end is connected to the first interface (i.e., the L1 end) of the three-way joint 11 and is connected, and one end of the air delivery pipeline 13 is connected to the second interface (i.e., the L2 end) of the three-way joint 11. One end of the vent line 14 is connected to the third interface (i.e., the L3 end) of the three-way joint 11 to form a connection, and the other end is used to connect to the air inlet end of the external air source (or directly connected to the atmosphere); the first solenoid valve 7 is arranged on the air inlet line 12 to control the on / off of the air inlet line 12; the second solenoid valve 8 is arranged on the vent line 14 to control the on / off of the vent 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 set of air supply mechanisms, respectively, to control the opening and closing states of the first solenoid valve 7 and the second solenoid valve 8.

[0050] When in use, the working principle of the control mechanism is: the opening and closing states of the first solenoid valve 7 and the second solenoid valve 8 in each air supply mechanism are controlled by the PLC controller, so that the strain layer specified by the external air source box is supplied with air, thereby controlling the soft actuator to perform bending and / or twisting deformation in the specified direction according to the Euler spiral form; after the soft actuator completes the action, the soft actuator is restored to its initial form by closing all the first solenoid valves 7 and opening all the second solenoid valves 8.

[0051] Furthermore, in order to prove that the above-mentioned soft actuator that realizes omnidirectional bending and twisting motion in space can realize bending and twisting motion in any direction, the finite element analysis method is used to simulate the bending and twisting motion performed by the actuator under different air supply conditions. Figure 8 In order to facilitate the description of the air supply conditions of different strain layers, each strain layer in the soft actuator for realizing omnidirectional bending and torsional motion in space in this embodiment is marked with a code.

[0052] Test 1:

[0053] The air chambers of each two adjacent strain layers in the soft actuator for realizing omnidirectional bending and torsion motion in space of this embodiment are driven by air supply separately, while the air chambers of the other two strain layers are not supplied with air, and the bending deformation of the soft actuator is observed. In this simulation test, the air supply pressure is set to 30Kpa of compressed air.

[0054] like Fig. 9Figure (a) shows a schematic diagram of the bending deformation of the soft actuator when air is supplied to the air chambers of the strain layer A and the strain layer B alone, and no air is supplied to the strain layer C and the strain layer D; Fig. 9 Figure (b) shows a schematic diagram of the bending deformation of the soft actuator when air is supplied to the air chambers of the strain layer B and the strain layer C alone, and no air is supplied to the strain layer A and the strain layer D; Fig. 9 Figure (c) shows a schematic diagram of the bending deformation of the soft actuator when air is supplied to the air chambers of the strain layer C and the strain layer D alone, and no air is supplied to the strain layer A and the strain layer B; Fig. 9 Figure (d) shows a schematic diagram of the bending deformation of the soft actuator when air is supplied to the air chambers of strain layer D and strain layer A separately, and no air is 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 air to the air chambers of two adjacent strain layers, the soft actuator can be driven to bend and deform in a specified direction.

[0055] Test 2:

[0056] The air chambers of each of the two opposite strain layers in the soft actuator for realizing omnidirectional bending and torsion motion in space of this embodiment are driven by air supply separately, while the air chambers of the other two strain layers are not supplied with air, and the bending deformation of the soft actuator is observed. In this simulation test, the air supply pressure is set to 30Kpa of compressed air.

[0057] like Fig.10 Figure (a) shows a schematic diagram of the bending deformation of the soft actuator when air is supplied to the air chambers of the strain layer A and the strain layer C alone, and no air is supplied to the strain layer B and the strain layer D; Fig.10 Figure (b) shows a schematic diagram of the bending deformation of the soft actuator when air is supplied to the air chambers of strain layer B and strain layer D separately, and no air is supplied to strain layer A and strain layer C; the above two schematic diagrams of the bending deformation of the soft actuator show that by supplying air to the air chambers of two opposite strain layers, the soft actuator can be driven to undergo torsional deformation in two opposite directions.

[0058] Test three:

[0059] The air chambers of two adjacent strain layers in the soft actuator for realizing spatial omnidirectional bending and torsion motion in this embodiment are driven by air supply, and the air chamber of another strain layer is driven by variable pressure air supply; in this simulation test, the air supply pressure to the air chambers of strain layer A and strain layer B is set to 30Kpa, and the air supply pressure to the air chamber of strain layer C is gradually increased from 0Kpa to 15Kpa, 20Kpa, 25Kpa, 30Kpa and 35Kpa. No air is supplied to strain layer D, and the bending deformation of the soft actuator is observed.

[0060] like Fig.11As shown, when the air supply is maintained at a constant pressure to the strain layer A and strain layer B in the soft actuator that realizes omnidirectional bending and torsion motion in space, and the air supply pressure to the air chamber of the strain layer C is gradually increased, it can be seen that while the soft actuator is bending and deforming, it can also use different air supply pressures to drive the soft actuator to undergo different degrees of twisting motion.

[0061] To summarize, the soft actuator for realizing omnidirectional bending and torsion motion in space of the present invention can perform bending motion in any of four directions and torsion motion in two directions by providing different air supply conditions. Furthermore, through the combination of bending motion and torsion motion, the soft actuator can be bent and torsion in any direction, thereby realizing a wider range of motion execution.

Claims

1. A soft actuator for realizing omnidirectional bending and torsion motion in space, characterized in that: The invention comprises an actuator, which is composed of a central layer (1), four restriction layers (2), two first strain layers (3) and two second strain layers (4); wherein the central layer (1) is a strip-shaped cube with a square radial cross section; the restriction layer (2) is a sheet-shaped body with an isosceles trapezoidal radial cross section; the four restriction layers (2) are respectively fixed on the four side wall surfaces of the central layer (1) in a manner that the side surfaces of the four restriction layers (2) with a small width are in contact with the wall surface of the central layer (1); the first strain layer (3) is a strip-shaped body with an isosceles trapezoidal radial cross section, which is composed of a head end ventilation module, a plurality of middle ventilation modules and a tail end ventilation module which are arranged in a straight line with equal spacing from front to back and are connected in sequence and integrally formed, and an oblique through groove which runs through in the width direction of the strain layer is formed between each two adjacent ventilation modules; each through groove is provided with a plurality of intermediate ventilation modules, and the plurality of intermediate ventilation modules are connected with each other in a straight line with equal spacing from front to back. A chamber is provided in the air module, and the chambers between adjacent ventilation modules are connected, so that an air chamber is formed in the first strain layer (3); the second strain layer (4) has the same structural composition as the first strain layer (3), and is in a mirror-symmetrical structure with the first strain layer (3); the two first strain layers (3) are fixed on the restriction layer (2) located on a group of opposite side walls of the central layer (1) in a manner that their small-sized layers are fitted with the large-width side layers of the restriction layer (2); the two second strain layers (4) are fixed on the restriction layer (2) located on another group of opposite side walls of the central layer (1) in a manner that their small-sized layers are fitted with the large-width side layers of the restriction layer (2); the central layer (1), the restriction layer (2), the first strain layer (3) and the second strain layer (4) are all made of elastic material.

2. The soft actuator for realizing omnidirectional bending and torsion motion in space according to claim 1, characterized in that: The axial length of the restriction layer (2) is the same as that of the central layer (1), the width of the layer on the side with a smaller width is the same as the side wall width of the central layer (1), and the angle formed between the layer on the side with a larger width and the adjacent inclined surface is 50° to 80°; the thickness of the restriction layer (2) is 1 mm to 3 mm.

3. The software actuator for realizing omnidirectional bending and torsion motion in space according to claim 1, characterized in that: In each strain layer, an angle α formed between the arrangement direction of the oblique through grooves and the axial direction of the strain layer is 50° to 80°.

4. The software actuator for realizing omnidirectional bending and torsion motion in space according to claim 1, characterized in that: A connection end (5) is provided on the front end surface of the ventilation module at the head end of each strain layer, and the inner cavity of the connection end (5) is connected to the air chamber of the strain layer.

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

6. The software actuator for realizing omnidirectional bending and torsion motion in space according to claim 1, characterized in that: In each strain layer, the head-end ventilation module is a block with a radial cross-section of an inverted isosceles trapezoid, and a chamber with the same radial cross-section of an inverted isosceles trapezoid is opened from the bottom surface; wherein, the chamber of the head-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 head-end ventilation module through a vent, and 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 head-end ventilation module is set as an inclined plane parallel to the front end face of the adjacent middle ventilation module, and extends outward from the bottom side of the rear end face to form a connecting portion, and a through groove connected to the chamber is centrally opened on the bottom surface of the connecting portion.

7. The software actuator for realizing omnidirectional bending and torsion motion in space according to claim 1, characterized in that: In each strain layer, the middle ventilation module is a block whose top and bottom surfaces are both parallelograms and whose radial cross-section is an inverted trapezoid, and a chamber is opened from the bottom surface, and a chamber whose top and bottom surfaces are also parallelograms and whose radial cross-section is an inverted trapezoid is opened from the bottom surface; wherein the bottom sides of the front and rear ends of the middle ventilation module extend outwards respectively and form connecting parts for connecting with the adjacent ventilation modules located on the front and rear sides respectively; and through grooves communicating with the chamber are centrally opened on the bottom surfaces of the connecting parts on both sides.

8. The software actuator for realizing omnidirectional bending and twisting motion in space according to claim 1, characterized in that: In each strain layer, the rear-end ventilation module is a block with a radial cross-section of an inverted isosceles trapezoid, and a chamber with the same radial cross-section of an inverted isosceles trapezoid is opened from the front side of the bottom surface; wherein the front end face of the rear-end ventilation module is set as an inclined surface parallel to the front end face of the adjacent middle ventilation module, and extends outward from the bottom side of the front end face to form a connecting portion, and a through groove connected to the chamber is centrally opened on the bottom surface of the connecting portion.

9. The software actuator for realizing omnidirectional bending and twisting motion in space according to claim 1, characterized in that: It also includes a control mechanism; the control mechanism includes four sets of air supply mechanisms respectively connected to the air inlet ends of the four strain layers; each set of air supply mechanisms is composed of a first solenoid valve, a second solenoid valve, a three-way joint, an air intake pipeline, an air supply pipeline and an air release pipeline; one end of the air intake pipeline is used to connect to an external air source, and the other end is connected to the first interface of the three-way joint to form a connection, one end of the air supply pipeline is connected to the second interface of the three-way joint to form a connection, and the other end is connected to the air intake end of the strain layer to form a connection, one end of the air release pipeline is connected to the third interface of the three-way joint 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 arranged on the air intake pipeline, and the second solenoid valve is arranged on the air release 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.

10. A method for driving a software actuator for realizing omnidirectional bending and twisting motion in space according to any one of claims 1 to 9, characterized in that: include: I. By ventilating the air chambers of any two adjacent strain layers, the soft actuator is bent and deformed in the corresponding direction; and / or, II. By ventilating the air chambers of any two opposite strain layers, the soft actuator is twisted and deformed in the corresponding direction.

Images