Modularized paper folding soft mechanical arm

Abstract

The invention 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. Through cooperative arrangement of inner fluid and rope drive, the paper folding module can rotate in the circumferential direction while stretching out and drawing back in the axial direction, and the problem that object grabbing fails due to the fact that the angle of an end effector is not suitable is solved.

Description

Technical Field

[0001] The invention 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 science and technology has promoted the widespread application of robotic arms in various fields. Traditional rigid robotic arms have greatly improved production efficiency and reduced costs due to their stable and reliable characteristics. However, as people's understanding of the working environment continues to improve, the limitations of rigid robotic arms have become increasingly prominent. Soft robotic arms are inspired by organisms and use a deformable flexible structure. They have a higher degree of freedom and perform better in complex environments.

[0003] However, most current soft robotic arms have a main body made of elastic material. With the help of equally spaced spacers, the main body produces various bending movements under the differential drive of cables. Nevertheless, since the main body is elastic but can only be compressed or contracted to a limited extent, the almost unchanged effective length greatly reduces the dexterity and workspace of the soft robotic arm. They greatly limit the flexibility and versatility of the robotic arm's operation and restrict the contact between people and machines. Therefore, a flexible, foldable or compressible structure with multiple degrees of freedom is needed to replace the original elastic main body.

[0004] Origami is a common three-dimensional structure based on stacked two-dimensional paper, which is composed 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 structures, advanced manufacturing technologies, such as digital modeling and 3D printing, have greatly improved the manufacturing efficiency and accuracy of origami structures. The many advantages of origami structures coincide with the current development trend of continuum robotic arms. Therefore, designing continuum robotic arms using origami structures is an important research direction. Summary of the invention

[0005] In view of the above problems, the object 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 object, the present invention adopts the following technical solutions:

[0007] The present invention provides a modular origami soft robot arm, comprising a wire drive module, a fluid drive module and an origami module, wherein the origami module is installed on the wire drive module, the fluid drive module is connected to the origami module, the fluid drive 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 drive module is used to fix the origami module after contraction.

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

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

[0010] The plane unfolded diagram of the origami unit is a rhombus with a crease structure, wherein the crease structure 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 in each small rhombus block, the peak crease is parallel to the wide side of the rhombus, the valley creases in the plurality of small rhombus blocks are parallel to each other, and 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 transverse counterclockwise spiral.

[0014] The plurality of origami units are alternately arranged as left-handed origami software and right-handed origami software in sequence, and 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 wire rope drive unit includes a servo, a servo wheel, a groove bearing and a wire rope, wherein the servo is mounted on a servo fixing frame and the output end is connected to the servo wheel, the groove bearing is rotatably mounted on the servo fixing frame, one end of the wire rope is wound around the servo wheel, and the other end passes through the groove bearing and is connected to each folding unit in sequence, and the servo drives the wire rope to be retracted and released.

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

[0019] The advantages and beneficial effects of the present invention are:

[0020] The present invention proposes a modular origami soft robotic arm, which adopts a combination of wire drive and fluid drive and a driver far away from the end actuator. The advantage of this driving method is that 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 of the end actuator and improve its carrying capacity and flexibility. At the same time, the easily damaged driving components are kept away from the end, which can reduce the risk of being affected by the outside world and improve the reliability and service life of the system. In addition, the centralized arrangement of the driving components is conducive to maintenance and replacement, and reduces 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 driving components at the end, which can expand the working range and load capacity of the robotic arm.

[0021] The present invention adopts fluid drive as the main mode, which simplifies the structure and ensures that the robot arm can be used both on land and underwater, thus improving the environmental adaptability. The simple structure means fewer parts are required, and the processing technology is relatively simple, which greatly reduces the manufacturing cost, which is a major advantage for the price-sensitive market. The structure is simple and clear, and maintenance and inspection are convenient; there are fewer faults and they are easy to repair, which improves the reliability of the equipment. In addition, the simple structure means that the overall weight is lighter, which is conducive to transportation and installation, and the design is more flexible, which can be more easily modified and optimized to meet different needs.

[0022] The invention increases the response speed by adding the auxiliary drive of the wire rope, that is, improves the real-time performance and control accuracy of the system, can track the control instructions faster, and reduce delays and lags. Rapid response is conducive to adapting to the dynamic changes of environmental changes and task requirements, and improving the dynamic adaptability of the system. At the same time, it shortens the system reaction time, enhances the ability to respond to emergencies, and improves the safety of the system. In addition, rapid response is conducive to the system to adapt to different working conditions more flexibly, and improves the versatility and adaptability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0026] Figure 4 It is a planar unfolded view of the origami software of the present invention;

[0027] Figure 5 is an axonometric view of the origami software of the present invention;

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

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

[0030] Figure 8 It is a hardware circuit framework diagram of the control system of the present invention.

[0031] In the figure: 1-servo, 2-servo wheel, 3-groove bearing, 4-rope, 5-servo fixing frame, 6-pipe, 7-servo fixing frame connecting plate, 8-upper baffle, 9-origami software, 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 present invention provides a modular origami soft robot arm, including a wire drive module, a fluid drive module and an origami module, wherein the origami module is installed on the wire drive module, the fluid drive module is connected to the origami module, the fluid drive 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 drive module is used to fix the origami module after contraction.

[0034] See also Figure 2 As shown, in the embodiment of the present invention, the paper folding module includes 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 in sequence, the steering gear fixing frame connecting plate 7 is connected to the wire driving module; the lower ends of the plurality of paper folding units are connected to the end effector connecting plate 11, and the end effector connecting plate 11 is used to install the end suction cup. The end suction cup and the end effector connecting plate 11 are fixed by screw holes reserved on the side.

[0035] In an 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 both 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 crease.

[0036] Furthermore, each origami soft body 9 is provided with an ear end 12, which is more convenient for fixing, and also increases the contact area when connected, thereby improving the sealing performance. Sealant is applied between the lower baffle plate 10 and the upper baffle plate 8 between two adjacent origami units to ensure their airtightness, and screws and nuts are used to ensure the stability of their structure.

[0037] See also Figure 3As 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 software. Figure 3 (b) is a right-handed origami software.

[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, the crease structure includes a peak crease forming a plurality of small rhombus blocks along the length direction and a valley crease folded along the acute angle diagonal line in each small rhombus block, the peak crease is parallel to the wide side of the rhombus, and the plurality of valley creases are parallel to each other; the peak crease and the valley crease are folded in opposite directions, forming a crease of 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, according to the characteristics of this origami structure, through the volume change in the compression chamber of the origami software 9, the planes on both sides of the valley fold in each small rhombus block move closer to each other or expand with the valley fold as the axis. When the compression chamber of the origami software 9 is under negative pressure, the volume becomes smaller, and the planes on both sides of the valley fold move closer to each other with the valley fold as the axis, that is, the plane CDE and the plane EDF move closer to each other with DE as the axis, realizing the rotation and height change Δh of the upper plane ACE and the lower plane BDF, and the height is H at this time. The extension and shortening of the origami robot arm and the axial rotation of the platform at the end of the robot arm are realized through the rotation and height change of the upper and lower planes.

[0040] See also Figure 6 As shown, in the embodiment of the present invention, both ends of the origami software 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-hand origami software. When the origami module is contracted, the end effector connecting plate 11 is rotated leftward and raised laterally, that is, a clockwise rotation is generated laterally. Figure 7 (a) shown.

[0042] Or, the plurality of origami units are right-hand origami software. When the origami module is contracted, the end effector connecting plate 11 is horizontally rotated rightward and raised, that is, a counterclockwise rotation is generated horizontally. Figure 7(c) as shown.

[0043] Alternatively, the plurality of origami units are alternately arranged as left-handed origami software and right-handed origami software. When the origami module is contracted, the end effector connecting plate 11 rises linearly, that is, the robot arm does not rotate horizontally 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 the embodiment of the present invention, the upper baffle 8 and the lower baffle 10 are made of acrylic plate with a thickness of 1 mm, and the origami software is made of TPU polyurethane 3D printing. In order to facilitate sealing, the upper baffle 8 and the lower baffle 10 are arranged inside the origami software 9. When using sealant, the effect between TPU and TPU is better than that between TPU and acrylic, and the lower baffle 10 of the previous module and the upper baffle 8 of the next module are fixed with screws to further enhance the sealing.

[0045] See also Figure 1 As shown, in the embodiment of the present invention, the wire rope drive module is a robot arm that meets the needs of wire rope drive. The wire rope drive module includes 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 includes a steering gear 1, a steering gear wheel 2, a groove bearing 3 and a wire rope 4, wherein the steering gear 1 is installed on the steering gear fixing frame 5 and the output end is connected to the steering gear wheel 2 through a pin interference fit, the groove bearing 3 is rotatably installed 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 connected to each paper folding unit in sequence, the groove bearing 3 turns the wire rope 4 from horizontal to longitudinal, and the steering gear 1 drives the wire rope 4 to be retracted and released.

[0046] In this embodiment, the number of the wire driving modules is three evenly distributed along the circumferential direction, and the three servo steering gears 1 are evenly distributed within the circular range thereof.

[0047] In an embodiment of the present invention, the fluid drive module satisfies the need for fluid drive for the robot arm. The fluid drive module includes a pipeline 6, which is mounted on the connecting plate 7 of the servo fixing frame and communicates with the inner cavity of the origami module at one end, and the other end of the pipeline 6 is connected to an external pump group. When the pump is pumped, a negative pressure is generated in the cabin of the origami module, and the length is shortened under the action of atmospheric pressure, and the rope 4 is retracted by the reversed servo 1 to fix the origami module. The end effector connecting plate 11 also rotates 120° in the horizontal direction.

[0048] The present invention is a modular origami soft robot arm based on Kresling origami, wherein the steering wheel 2, the steering frame 5, the steering frame connecting plate 7, and the end effector connecting plate 11 are all made of resin 3D printing. The outer diameter of the steering wheel 2 is φ36, and the inner diameter is φ20. The steering wheel 2 can store at least 1m of rope 4 inside, which can ensure that twenty origami modules are connected in series and stretched to the maximum extent. Considering factors such as durability, the rope 4 specifically uses a Dyneema line. The pipe 6 can inflate or release gas or liquid to the origami module, and the pipe 6 uses a 4mm transparent catheter. The upper baffle 8 and the lower baffle 10 are made of 1mm thick acrylic plates, and the thickness of 1mm is considered to not affect the normal contraction of the origami soft body. The origami soft body is made of TPUa70 polyurethane 3D printing. The softness of a70 ensures that the origami soft body can shrink and move normally, while ensuring a certain rigidity, so that it can move according to the predetermined crease.

[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, and the origami software 9 is formed after folding. The radius R of the hexagonal circumscribed circle of the origami software 9 is Where a is the side length of the origami soft body 9 in the columnar structure, n is the number of sides of the cylinder, a=l k / n=30mm.l k is the perimeter of the origami soft body 9, 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 fully 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 control is a Raspberry Pi, and its IO pins, ADC pins, DAC pins, power output pins, and GND pins are mainly used. The main control controls the on and off of the micro air pump, the thin proportional valve, and the 2-position 3-way solenoid valve through the IO pin through the 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 control. At the same time, the 5V pin and GND of the main control are connected to the strain gauge signal conversion module for power supply. The work or not of the origami soft arm is carried out by pumping and releasing air through the micro air pump. The thin proportional valve can accurately control the air pressure of the micro air pump. When the two-position solenoid valve works 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 movement of the arm by raising and lowering the pressure on the cabin in the channel, and with the assistance of the servo and the rope, the soft arm can move with full freedom to grasp 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 axially extending and retracting, thus solving the problem of failure of the end effector to grasp an object due to an inappropriate angle. Since the origami module structure adopted has the characteristics of flexibility and self-recovery, after successfully grasping an object, it can be reset without external interference, and flexible grasping can be achieved. While solving the problem of object grasping, it also has excellent adaptability, and realizes the integration of the structure and drive of the soft robot 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 the driving 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 protection scope 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 protection scope of the present invention.

Claims

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

2. The modular origami soft robot 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 which are installed below the steering gear fixing frame connecting plate (7) and are sequentially connected in series, the steering gear fixing frame connecting plate (7) being connected to the wire rope driving module; and the lower ends of the plurality of paper folding units being 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.

3. The modular origami soft robot arm according to claim 2, characterized in that: The plane unfolded diagram of the origami unit is a rhombus with a crease structure, wherein the crease structure 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 in each small rhombus block, the peak crease is parallel to the wide side of the rhombus, the valley creases in the plurality of small rhombus blocks are parallel to each other, and the folding directions of the peak crease and the valley crease are opposite.

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

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

7. The modular origami soft robot arm according to claim 4, characterized in that: The plurality of origami units are alternately arranged as left-hand origami software and right-hand origami software in sequence, and when the origami module is contracted, the end effector connecting plate (11) rises or falls linearly.

8. The modular origami soft robot 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 robot arm according to claim 2, characterized in that: The wire rope driving module comprises a steering gear fixing frame (5) and a plurality of wire rope driving units arranged on the steering gear fixing frame (5); The wire rope driving 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 the 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 connected to each paper folding unit in sequence, and the steering gear (1) drives the wire rope (4) to be retracted and released.

10. The modular origami soft robot arm according to claim 2, characterized in that: The fluid drive module comprises a pipeline (6), wherein the pipeline (6) is mounted on the steering gear fixing frame connecting plate (7) and one end of the pipeline is 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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