Modularized paper folding soft mechanical arm

Abstract

The utility model belongs to the technical field of soft robots, and particularly relates to a modularized paper folding soft mechanical arm. Comprising a rope driving module, a fluid driving module and a paper folding module, the paper folding module is installed on the rope driving module, the fluid driving module is connected with the paper folding module, the fluid driving module is used for generating positive pressure or negative pressure on the paper folding module to enable the paper folding module to stretch out and draw back, and the rope driving module is used for fixing the paper folding module after contraction. The paper folding module comprises a steering engine fixing frame connecting plate and a plurality of paper folding units which are mounted below the steering engine fixing frame connecting plate and are sequentially connected in series, and the steering engine fixing frame connecting plate is connected with the rope driving module; and the lower ends of the paper folding units are connected with the end effector connecting plate. According to the utility model, through the cooperative arrangement of the internal fluid and the rope drive, the paper folding module can rotate circumferentially while stretching out and drawing back axially, and the problems of object grabbing failure and the like caused by the uncomfortable angle of the end effector are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of soft robots, and in particular relates to a modular origami soft robotic arm. Background Art

[0002] The rapid development of modern technology has driven the widespread application of robotic arms in various fields. Traditional rigid robotic arms, with their stability and reliability, have significantly improved production efficiency and reduced costs. However, as people's understanding of the working environment continues to improve, the limitations of rigid robotic arms are becoming increasingly apparent. Soft robotic arms, inspired by biological organisms, utilize a flexible, deformable structure, offering greater degrees of freedom and superior performance in complex environments.

[0003] However, most current soft robotic arms have a main body made of elastic material. With the help of evenly spaced spacers, the main body generates various bending movements under the differential drive of cables. However, since the main body is elastic but can only undergo limited compression or contraction, the nearly constant effective length significantly reduces the dexterity and workspace of the soft robotic arm. This significantly limits the manipulator's operational flexibility and versatility, and restricts human-machine interaction. Therefore, a flexible, foldable or compressible structure with multiple degrees of freedom is needed to replace the existing elastic main body.

[0004] Origami is a common three-dimensional structure made from stacked two-dimensional paper, consisting of one or more units. The structure can be unfolded, folded, and deformed by folding, flipping, or rotating. With the continuous development and application of origami, advanced manufacturing technologies such as digital modeling and 3D printing have greatly improved the efficiency and precision of origami manufacturing. The many advantages of origami structures coincide with the current development trend of continuum manipulators. Therefore, using origami structures to design continuum manipulators is an important research direction. Utility Model Content

[0005] In view of the above problems, the purpose of the present invention is to provide a modular origami soft robotic arm to achieve the purpose of designing a continuum robotic arm using an origami structure.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] The utility model provides a modular origami soft robotic arm, comprising a wire-driven module, a fluid-driven module and an origami module, wherein the origami module is mounted on the wire-driven module, the fluid-driven module is connected to the origami module, the fluid-driven module is used to generate positive or negative pressure on the origami module to cause the origami module to expand and contract, and the wire-driven module is used to fix the origami module after contraction.

[0008] The origami module includes a servo fixing frame connecting plate and a plurality of origami units installed below the servo fixing frame connecting plate and connected in series in sequence. The servo fixing frame connecting plate is connected to the rope driving module; the lower ends of the plurality of origami units are connected to the end effector connecting plate.

[0009] Each origami unit includes an origami soft body and an upper baffle and a lower baffle connected at both ends of the origami soft body. The origami soft body adopts a hollow spiral polyhedron structure formed by origami, and the origami soft body can shrink according to a predetermined fold.

[0010] The planar unfolding diagram of the origami unit is a rhombus with a crease structure, which includes a peak crease forming a plurality of small rhombus blocks along the length direction and a valley crease folded along an acute-angle diagonal line within each small rhombus block. The peak crease is parallel to the wide side of the rhombus, and the valley creases in the plurality of small rhombus blocks are parallel to each other. The folding directions of the peak crease and the valley crease are opposite.

[0011] The origami unit is a left-handed origami software and / or a right-handed origami software.

[0012] The plurality of origami units are all left-handed origami software. When the origami module contracts, the end effector connecting plate rises or falls in a transverse clockwise spiral.

[0013] The plurality of origami units are all right-handed origami software. When the origami module contracts, the end effector connecting plate rises or falls in a counterclockwise spiral.

[0014] The plurality of origami units are alternately arranged as left-handed origami software and right-handed origami software. When the origami module contracts, the end effector connecting plate rises or falls linearly.

[0015] The upper baffle and the lower baffle are made of acrylic plates with a thickness of 1 mm, and the origami software is made of TPU polyurethane 3D printing.

[0016] The wire rope driving module includes a steering gear fixing frame and a plurality of wire rope driving units arranged on the steering gear fixing frame;

[0017] The rope drive unit includes a servo, a servo wheel, a groove bearing and a rope, wherein the servo is installed on the servo fixing frame and the output end is connected to the servo wheel. The groove bearing is rotatably installed on the servo fixing frame. One end of the rope is wrapped around the servo wheel, and the other end passes through the groove bearing and is connected to each origami unit in sequence. The servo drives the rope to be retracted and extended.

[0018] The fluid drive module includes a pipeline, which is installed on the connecting plate of the steering gear fixing frame and has one end connected to the inner cavity of the origami module, and the other end of the pipeline is connected to the external pump group.

[0019] The advantages and beneficial effects of the utility model are:

[0020] The present utility model proposes a modular origami soft robotic arm, which adopts a combination of rope drive and fluid drive and a driver that is far away from the end actuator. The advantages of this drive method are: the driver is far away from the end actuator, and the heavier driver is placed at the base of the robotic arm, which can reduce the load on the end actuator and improve its load-bearing capacity and flexibility. At the same time, the risk of external influences can be reduced by moving the easily damaged drive components away from the end, which improves the reliability and service life of the system. In addition, the centralized arrangement of the drive components is conducive to maintenance and replacement, reducing interference with the entire robotic arm. Placing the driver at the base is conducive to optimizing the dynamic model and improving control accuracy. Finally, there is no need to reserve space for the drive components at the end, which can expand the working range and load capacity of the robotic arm.

[0021] This utility model utilizes fluid propulsion as its primary driving mechanism, simplifying the structure and ensuring the arm can be used both on land and underwater, thus improving its environmental adaptability. The simple structure requires fewer parts and a relatively simple processing technique, significantly reducing manufacturing costs—a significant advantage for price-sensitive markets. The simple and clear structure facilitates maintenance and inspection, resulting in fewer and easier repairs, improving equipment reliability. Furthermore, the simple structure reduces overall weight, facilitating transportation and installation, and provides a more flexible design that can be easily modified and optimized to meet diverse needs.

[0022] The addition of a cord-assisted drive in this utility model improves response speed, enhancing the system's real-time performance and control accuracy, enabling faster tracking of control commands and reducing delays and lags. This rapid response facilitates adaptation to environmental changes and dynamic changes in task requirements, improving the system's dynamic adaptability. Furthermore, it shortens system reaction time, enhances emergency response capabilities, and improves system safety. Furthermore, rapid response allows the system to more flexibly adapt to diverse operating conditions, improving its versatility and adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a modular origami soft robotic arm of the present invention;

[0024] Figure 2 This is an exploded schematic diagram of the origami module in the present invention;

[0025] Figure 3 Schematic diagram of the structure of the origami unit in the present invention: (a) left-handed origami software, (b) right-handed origami software;

[0026] Figure 4 This is a planar unfolding diagram of the origami software in the present invention;

[0027] Figure 5This is an axonometric drawing of the origami software in the present invention;

[0028] Figure 6 A top view of the origami soft object of the present invention;

[0029] Figure 7 Schematic diagram of different types of origami modules in the present invention;

[0030] Figure 8 This is the hardware circuit framework diagram of the control system of this utility model.

[0031] In the figure: 1-servo, 2-servo wheel, 3-grooved bearing, 4-rope, 5-servo fixing frame, 6-pipe, 7-servo fixing frame connecting plate, 8-upper baffle, 9-origami soft body, 10-lower baffle, 11-end effector connecting plate, 12-ear end. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] See also Figures 1 to 8 As shown, the utility model provides a modular origami soft robotic arm, including a wire rope driving module, a fluid driving module and an origami module, wherein the origami module is installed on the wire rope driving module, the fluid driving module is connected to the origami module, the fluid driving module is used to generate positive pressure or negative pressure on the origami module to make the origami module expand and contract, and the wire rope driving module is used to fix the origami module after contraction.

[0034] See also Figure 2 As shown, in this embodiment of the present invention, the paper-folding module includes a servo mounting frame connecting plate 7 and multiple paper-folding units mounted below the servo mounting frame connecting plate 7 and connected in series. The servo mounting frame connecting plate 7 is connected to the cable drive module. The lower ends of the multiple paper-folding units are connected to the end effector connecting plate 11, which is used to mount the end effector suction cup. The end effector and the end effector connecting plate 11 are fixed together using screw holes retained on the side.

[0035] In the embodiment of the present invention, each origami unit includes an origami software 9 and an upper baffle 8 and a lower baffle 10 connected to the two ends of the origami software 9, wherein the origami software 9 adopts a hollow spiral polyhedron structure formed by origami, and the origami software 9 can shrink according to a predetermined fold.

[0036] Furthermore, each origami unit 9 is equipped with an ear 12, which makes it easier to fix and increases the contact area when connected, improving the seal. Sealant is applied between the lower baffle 10 and the upper baffle 8 between adjacent origami units to ensure airtightness, and screws and nuts are used to ensure the stability of the structure.

[0037] See also Figure 3 As shown, in the embodiment of the present invention, the origami unit is a left-hand origami software and / or a right-hand origami software. Figure 3 (a) is a left-handed origami soft object. Figure 3 (b) is a right-handed origami soft object.

[0038] See also Figure 4 As shown, in the embodiment of the present invention, the plane unfolding diagram of the origami unit is a rhombus with a crease structure, which includes a peak crease forming multiple small rhombus blocks along the length direction and a valley crease folded along the acute angle diagonal line within each small rhombus block. The peak crease is parallel to the wide side of the rhombus, and the multiple valley creases are parallel to each other; the peak crease and the valley crease fold in opposite directions, forming a crease with a peak and valley structure. The obtuse angle of the rhombus is β0, the acute angle is δ, and the angle between the peak crease and the valley crease is The length and width of the rhombus are L k and b; because the peak crease is parallel to the wide side of the rhombus, the length of the peak crease is b; the height of the rhombus is h0. The length and width of the small rhombus are b and a respectively, the length of the acute diagonal (valley crease) is c, and the height of the small rhombus is h0.

[0039] See also Figure 5 As shown, in the embodiment of the present invention, based on the characteristics of this origami structure, the volume changes within the compression chamber of the origami soft body 9 cause the two planes on either side of the valley fold in each small diamond-shaped block to converge or expand with the valley fold as the axis. When the compression chamber of the origami soft body 9 experiences negative pressure, the volume decreases, and the two planes on either side of the valley fold converge with the valley fold as the axis. Specifically, planes CDE and EDF converge with DE as the axis, causing the upper and lower planes ACE and BDF to rotate and change in height by Δh, with the height at this point being H. This rotation and height change of the upper and lower planes enables the origami robot arm to extend and contract, and the robot arm's end platform to rotate axially.

[0040] See also Figure 6 As shown, in the embodiment of the present invention, both ends of the origami soft object 9 are non-overlapping hexagons, and the hexagons at both ends have a common circumscribed circle. The radius of the circumscribed circle is R, and the angle between the diagonal line passing through the center of the upper hexagon and the diagonal line passing through the center of the lower hexagon is θ.

[0041] See also Figure 7 As shown, in the embodiment of the present invention, the plurality of origami units are all left-handed origami soft bodies. When the origami module is contracted, the end effector connecting plate 11 rotates leftward and rises horizontally, that is, it rotates clockwise horizontally. Figure 7 As shown in (a).

[0042] Alternatively, the plurality of origami units are all right-handed origami soft bodies. When the origami module contracts, the end effector connecting plate 11 rotates rightward and rises horizontally, that is, it rotates counterclockwise horizontally. Figure 7 (c) shown.

[0043] Alternatively, multiple origami units are alternately arranged as left-handed origami soft bodies and right-handed origami soft bodies. When the origami module contracts, the end effector connecting plate 11 rises linearly, that is, the robot arm does not rotate laterally when shortening, but only shortens. Figure 7 By integrating these different types of modules, robotic arms with different functions can be conceived for a wide range of applications.

[0044] In this embodiment of the utility model, the upper and lower baffles 8 and 10 are made of 1mm thick acrylic sheets, and the origami soft body is 3D-printed with TPU polyurethane. To facilitate sealing, the upper and lower baffles 8 and 10 are placed inside the origami soft body 9. When using sealant, TPU-to-TPU seals better than TPU-to-acrylic seals. Furthermore, screws are used to secure the lower baffle 10 of the previous module to the upper baffle 8 of the next module, further enhancing the seal.

[0045] See also Figure 1 As shown, in an embodiment of the present invention, a wire rope drive module satisfies the needs of wire rope drive for a robotic arm. The wire rope drive module includes a servo mounting frame 5 and multiple wire rope drive units mounted on the servo mounting frame 5. The wire rope drive units include a servo 1, a servo wheel 2, a groove bearing 3, and a wire rope 4. The servo 1 is mounted on the servo mounting frame 5, and its output end is connected to the servo wheel 2 via a pin interference fit. The groove bearing 3 is rotatably mounted on the servo mounting frame 5. One end of the wire rope 4 is wrapped around the servo wheel 2, and the other end passes through the groove bearing 3 and is connected to each paper folding unit in sequence. The groove bearing 3 rotates the wire rope 4 from horizontal to vertical, and the servo 1 drives the wire rope 4 to be retracted and extended.

[0046] In this embodiment, the number of the wire drive modules is three and they are evenly distributed along the circumference, and the three servo steering engines 1 are evenly distributed within the circular range.

[0047] In an embodiment of the present invention, a fluid drive module satisfies the fluid drive requirements of the robotic arm. The fluid drive module includes a pipe 6, which is mounted on a connecting plate 7 of a servo mounting bracket and communicates with the inner cavity of the origami module at one end. The other end of the pipe 6 is connected to an external pump assembly. When the pump is evacuated, a negative pressure is generated in the cabin of the origami module, shortening the length under the action of atmospheric pressure. The reversed servo 1 then retracts the wire 4 to secure the origami module. The end effector connecting plate 11 also rotates 120° laterally.

[0048] This modular origami soft robotic arm, based on Kresling origami, features a servo wheel 2, servo mount 5, servo mount connecting plate 7, and end effector connecting plate 11, all made from resin 3D printing. The servo wheel 2 has an outer diameter of φ36 and an inner diameter of φ20. It can store at least 1 meter of cord 4, ensuring that twenty origami modules can be connected in series and extended to their maximum extent. The cord 4, designed for durability, is made of Dyneema line. The pipe 6, which allows for the inflating and deflating of air or liquid into origami modules, utilizes a 4mm transparent conduit. The upper and lower baffles 8 and 10 are made from 1mm-thick acrylic sheets. The 1mm thickness is chosen to ensure the origami soft body does not contract normally. The origami soft body is 3D printed using TPUa70 polyurethane. The softness of a70 ensures the origami soft body can contract normally while maintaining a certain rigidity, allowing it to follow the predetermined creases.

[0049] See also Figures 4 to 6 As shown, in the embodiment of the present invention, the upper end point A and the upper fold points C and E are marked on the upper long side of the rhombus, and the lower end point B and the lower fold points D and F are marked on the lower long side. After folding, an origami soft object 9 is formed. The radius R of the hexagonal circumscribed circle of the origami soft object 9 is Where a is the side length of the origami soft body 9 in the cylindrical structure, n is the number of sides of the cylinder, and a=l k / n=30mm.l k is the perimeter of the origami soft body 9, and the height h0 between the upper and lower planes, h0 = bsinδ, where δ is the angle between the line segment EF (peak crease) and the horizontal plane (the acute angle of the rhombus), and b is the length of the peak crease, that is, Where θ is the angle between plane ACE and plane BDF, and θ=2π / n-2arcsin(bcosδ / 2R)≈35°. If the Kresling fold can be completely folded, the Kresling fold must satisfy According to the above formula, it is finally confirmed that β0=105°, h0≈36.5mm. β0 is the obtuse angle of the rhombus, It is the angle between the mountain crease and the valley crease.

[0050] See also Figure 8As shown, in the embodiment of the present invention, the main controller is a Raspberry Pi, and its IO pins, ADC pins, DAC pins, power output pins, and GND pins are mainly used. The main controller controls the on and off of the micro air pump, thin proportional valve, and 2-position 3-way solenoid valve respectively through the IO pins through a 24V MOS amplifier. The air pressure control of the thin proportional valve is mainly controlled by outputting an analog voltage through the DAC pin of the main controller. At the same time, the 5V pin and GND of the main controller are connected to the strain gauge signal conversion module for power supply. The operation of the origami soft arm is controlled by the micro air pump to pump and release air. The thin proportional valve can accurately control the air pressure of the micro air pump. When the two solenoid valves work at intervals, the origami soft arm reciprocates up and down.

[0051] The soft robotic arm of the present invention is mainly a Kresling structure, in which one or multiple origami modules connected in series realize the longitudinal linear motion of the arm by raising and lowering the pressure of the cabin in the channel. With the assistance of the servo and the rope, the soft arm can move with full freedom to realize the grasping of objects.

[0052] The present invention is a soft robot based on Kresling origami. Through the coordinated arrangement of internal fluid and wire drive, the origami module can be radially rotated while expanding and contracting axially, thus solving the problem of the end effector failing to grasp an object due to an inappropriate angle. Since the origami module structure adopted is flexible and self-recovering, it can be reset after successfully grasping an object without external interference, thus enabling flexible grasping. While solving the problem of object grasping, it also has excellent adaptability and realizes the integration of the structure and drive of the soft robotic arm, with the advantages of high power density, low power consumption, and quietness. At the same time, since there are no mechanical parts and friction losses except for the drive part, the flexible fluid pump has high electromechanical efficiency and light weight.

[0053] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A modular origami soft robotic arm, characterized in that: It includes a wire-driven module, a fluid-driven module and an origami module, wherein the origami module is installed on the wire-driven module, the fluid-driven module is connected to the origami module, the fluid-driven module is used to generate positive or negative pressure on the origami module to make the origami module expand and contract, and the wire-driven module is used to fix the origami module after it is contracted.

2. The modular origami soft robotic arm according to claim 1, characterized in that: The paper folding module comprises a steering gear fixing frame connecting plate (7) and a plurality of paper folding units installed below the steering gear fixing frame connecting plate (7) and connected in series, wherein the steering gear fixing frame connecting plate (7) is connected to the wire rope driving module; and the lower ends of the plurality of paper folding units are connected to the end effector connecting plate (11); Each origami unit comprises an origami soft body (9) and an upper baffle (8) and a lower baffle (10) connected to both ends of the origami soft body (9), wherein the origami soft body (9) adopts a hollow spiral polyhedron structure formed by origami, and the origami soft body (9) can perform contraction movement according to a predetermined fold line.

3. The modular origami soft robotic arm according to claim 2, characterized in that: The planar unfolding diagram of the origami unit is a rhombus with a crease structure, which includes a peak crease forming a plurality of small rhombus blocks along the length direction and a valley crease folded along an acute-angle diagonal line within each small rhombus block. The peak crease is parallel to the wide side of the rhombus, and the valley creases in the plurality of small rhombus blocks are parallel to each other. The folding directions of the peak crease and the valley crease are opposite.

4. The modular origami soft robotic arm according to claim 2, characterized in that: The origami unit is a left-handed origami software and / or a right-handed origami software.

5. The modular origami soft robotic arm according to claim 4, characterized in that: The plurality of origami units are all left-handed origami soft bodies. When the origami modules are contracted, the end effector connecting plate (11) rises or falls in a transverse clockwise spiral.

6. The modular origami soft robotic arm according to claim 4, characterized in that: The plurality of origami units are all right-handed origami soft bodies. When the origami module contracts, the end effector connecting plate (11) rises or falls in a counterclockwise spiral transversely.

7. The modular origami soft robotic arm according to claim 4, characterized in that: The plurality of origami units are alternately arranged as left-handed origami soft bodies and right-handed origami soft bodies. When the origami modules are contracted, the end effector connecting plate (11) rises or falls linearly.

8. The modular origami soft robotic arm according to claim 2, characterized in that: The upper baffle (8) and the lower baffle (10) are made of acrylic plates with a thickness of 1 mm, and the origami software is made of TPU polyurethane 3D printing.

9. The modular origami soft robotic arm according to claim 2, characterized in that: The wire rope drive module comprises a steering gear fixing frame (5) and a plurality of wire rope drive units arranged on the steering gear fixing frame (5); The wire rope drive unit comprises a steering gear (1), a steering gear wheel (2), a groove bearing (3) and a wire rope (4), wherein the steering gear (1) is mounted on a steering gear fixing frame (5) and an output end is connected to the steering gear wheel (2), the groove bearing (3) is rotatably mounted on the steering gear fixing frame (5), one end of the wire rope (4) is wound around the steering gear wheel (2), and the other end passes through the groove bearing (3) and is sequentially connected to each paper folding unit, and the steering gear (1) drives the wire rope (4) to be retracted and extended.

10. The modular origami soft robotic arm according to claim 2, characterized in that: The fluid drive module comprises a pipeline (6), which is mounted on the steering gear fixing frame connecting plate (7) and has one end connected to the inner cavity of the origami module, and the other end of the pipeline (6) is connected to an external pump group.

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