A bistable gripper based on hydroelastic origami structure and a manufacturing method thereof

Abstract

The application discloses a bistable gripper based on a water bomb origami structure and a manufacturing method thereof, and comprises a driving unit, a rigid connecting piece and a grabbing unit. The rigid connecting piece is used for connecting the grabbing unit and the driving unit. The grabbing unit comprises a water bomb origami unit and a clamping jaw arranged around the water bomb origami unit. Under the driving of the driving unit, the water bomb origami unit is unfolded and folded through the rigid connecting piece, and then the clamping jaw is driven to grab and release. The application has wide applicability and significant economic benefits in practical application, and can provide a novel, efficient, low-cost and multifunctional grabbing solution for the technical field of soft robot.

Description

Technical Field

[0001] The present invention relates to the technical field of soft robots, and in particular to a bistable gripper based on a water bullet origami structure and a manufacturing method thereof. Background Art

[0002] A bistable gripper based on a water-elastic origami structure is a novel soft robotics technology. This structure possesses two stable states—an initial state and a grasping state. Under external force, the structure can rapidly switch from the initial state to the grasping state, enabling fast passive grasping. This bistable gripper based on a water-elastic origami structure can achieve both fast passive grasping and fast active grasping. This bistable gripper can be used in spatial capture systems to grasp fast-moving objects, or in the manipulator of industrial robots to quickly and repeatedly grasp a variety of fragile objects. Due to its controllable grasping modes, controllable response speed, and low cost, this gripper has broad application prospects in automated operations and task execution in specialized environments. In summary, the bistable gripper based on a water-elastic origami structure, with its unique bistable properties and multiple grasping modes, provides an efficient, flexible, and cost-effective solution for the field of soft robotics. However, current soft grippers are slow in practical applications, making high-speed grasping a challenge. Although programmable bistable actuators based on foldable, adjustable bistable structures can achieve fast and diverse grasping, further improving response speed and grasping efficiency remains a challenge. Therefore, to address these technical issues, it is necessary to provide a pneumatic flexible gripper with a high response speed. Summary of the Invention

[0003] The present invention relates to the field of soft robotics technology and specifically discloses a bistable gripper with multiple grasping modes based on a water bullet origami structure and a method for manufacturing the same. This gripper is designed to address the issues of the existing technology, which suffer from a single grasping mode and complex manufacturing. It provides a bistable gripper with a simple structure, convenient manufacturing, and fast response speed. This gripper is capable of maintaining grasping capabilities in the absence of external forces, enabling both active and passive grasping modes. Through its unique design, the bistable gripper of the present invention not only improves grasping flexibility and adaptability, but also reduces energy consumption, broadening the application scope of soft robotics technology.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A bistable gripper based on a water bullet origami structure comprises: a drive unit, a rigid connector, and a gripping unit; the rigid connector is used to connect the gripping unit to the drive unit; the gripping unit comprises a water bullet origami unit and clamps arranged around the water bullet origami unit. Under the drive of the drive unit, the rigid connector drives the water bullet origami unit to expand and collapse, thereby driving the clamps to grasp and release.

[0006] Furthermore, the driving unit includes a sleeve, a piston and a piston rod. The upper end of the sleeve is connected to the polyester PU tube of the air drive equipment. The piston is slidingly fitted in the sleeve. The top of the piston is fixedly connected to the piston, and the bottom of the piston rod is connected to the top of the water bomb origami unit.

[0007] Furthermore, the bottom end of the piston rod is a frustum, which is engaged with the vertex of the water bullet origami unit.

[0008] Furthermore, the water bomb origami unit includes a vertex and eight folds, wherein the eight folds include four mountain folds and four valley folds, and the eight folds are completely symmetrical and can be completely unfolded into a plane.

[0009] Furthermore, the grabbing unit (3) is folded from a plane into a three-dimensional structure, and its plane is formed by pasting three layers of materials, wherein the upper and lower layer materials are PET films, and the middle layer material is a woven carbon fiber epoxy resin composite material plate, and the PET film and the woven carbon fiber epoxy resin composite material plate are connected by 3M tape paper, and the multi-layer structure is stacked from top to bottom in the order of PET film, 3M tape paper, woven carbon fiber epoxy resin composite material plate, 3M tape paper, and PET film.

[0010] Furthermore, the rigid connecting part includes a base, a connecting rod and a connecting hinge, the connecting hinge includes a connecting seat, a steering sleeve, and a bayonet assembly, the steering sleeve is movably arranged on the connecting seat through the bayonet assembly, the connecting seat is fixed to the outside of the driving unit, and the connecting seat is fixed to the water bomb origami unit; one end of the connecting rod is connected to the connecting hinge, and the other end is connected to the base, the base is fixed to the outside of the sleeve, and the bayonet assembly includes an annular buckle and a buckle base, the annular buckle passes through the connecting seat and the steering sleeve and is fixed and limited by the buckle base.

[0011] Furthermore, the water bullet origami unit has a bistable characteristic, and the bistable gripper can realize two grasping modes: active grasping and passive grasping. In the active grasping mode, the water bullet origami unit protrudes upward, that is, the top of the water bullet origami unit is higher than the crease, and the vacuum pump connected to the upper end of the sleeve provides negative pressure to drive the piston rod to move upward, and the water bullet origami unit is retracted, so that the grasping unit can grasp; in the passive grasping mode, the water bullet origami unit protrudes downward, that is, the top of the water bullet origami unit is lower than the crease, and when the grasped object touches the center point of the water bullet origami unit, the contact force causes the top of the water bullet origami unit to move upward to the critical value of the stable transition, triggering the bistable transition of the water bullet origami unit, and the water bullet origami unit is retracted to achieve grasping.

[0012] Furthermore, the sleeve and the piston rod are made of resin material by 3D printing, and the piston is made of rubber material.

[0013] A method for manufacturing a bistable gripper based on a water-elastic origami structure comprises the following steps:

[0014] Step 1: The gripping unit is made of a woven carbon fiber epoxy resin composite material. The woven carbon fiber epoxy resin composite prepreg is cut into eight isosceles triangles and eight obtuse triangles using a cutting machine. The eight isosceles triangles form a water bullet origami unit, and the eight obtuse triangles form four grippers. The water bullet origami unit and grippers are prepared using an autoclave process.

[0015] Step 2: Attach 3M tape to the PET film and fix the cured woven carbon fiber epoxy composite grabbing unit to the PET film according to the drawing, leaving a 2mm gap between the sides of each triangle. Cover the first PET film with the carbon fiber layer with a second PET film with 3M tape to obtain a multilayer structure.

[0016] Step 3: Use a laser cutting machine to cut out the plane shape of the multi-layer structure of the grabbing unit, make dotted line cuts at the creases, and continuously cut the outer contour of the four-pointed star. The outer contour cutting size is larger than the woven carbon fiber epoxy resin composite material layer, so the laser cutting layer does not contain the woven carbon fiber epoxy resin composite material layer, and the cut grabbing unit is pre-folded;

[0017] In step 3, the two layers of PET film with 3M tape attached are cut by laser, and the materials at the cut are melted and stuck together;

[0018] Step 4: Use 3D printing technology to print the rigid connector and drive unit of resin material;

[0019] Step 5: Connect the drive unit and the gripping unit through rigid connectors to assemble the gripper.

[0020] Step 6: Connect the upper end of the sleeve and the air drive equipment through the polyester PU tube.

[0021] The present invention has the following beneficial effects:

[0022] 1) Simple structure and easy production: The bistable gripper of the present invention adopts a modular design, and each component is easy to manufacture and assemble, which greatly reduces production cost and time.

[0023] 2) Fast response speed: Through pneumatic drive, the gripper of the present invention can achieve fast response, quick grasping and releasing actions, and is suitable for application scenarios that require fast operation.

[0024] 3) Strong adaptability: Due to the bistable design, the gripper can adapt to objects of different shapes and sizes and achieve stable grasping.

[0025] 4) Reusable: Due to the excellent mechanical properties of PET film and woven carbon fiber epoxy resin composite material, the gripper has a long service life and high durability.

[0026] 5) Dual grasping mode: It can maintain grasping ability without external force, realizing both active grasping and passive grasping modes.

[0027] In summary, the bistable gripper of the present invention is not only technologically innovative but also widely applicable and economically beneficial in practical applications. The implementation of the present invention can provide a new, efficient, low-cost, and multifunctional gripping solution for the field of soft robotics. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 is a top view of the present invention;

[0030] Figure 3 is a two-dimensional schematic diagram of the gripping unit of the present invention;

[0031] Figure 4 Schematic diagram of two grabbing modes of the grabbing unit of the present invention;

[0032] Figure 5 This is a schematic diagram of the grasping state of the grasping unit of the present invention;

[0033] Figure 6 is a structural diagram of the rigid connector of the present invention;

[0034] Figure 7 is a structural diagram of the connecting hinge of the present invention;

[0035] Figure 8is a structural diagram of a base of the present application;

[0036] Figure 9 is a structural diagram of a driving unit of a bistable gripper of the present application;

[0037] Figure 10 is a schematic diagram of a multi-layer structure of a bistable gripper of the present application;

[0038] In the figure: 1, driving unit; 101, polyester type PU tube; 102, piston; 103, piston rod; 104, cavity; 105, sleeve; 2, rigid connecting piece; 201, connecting hinge; 3, gripping unit; 301, water bomb origami unit; 302, clamping jaw; 4, base; 5, connecting rod; 6, turning sleeve; 7, bayonet; 8, connecting seat; 9, snap ring. DETAILED DESCRIPTION

[0039] The present application is further described below in conjunction with the accompanying drawings of the specification.

[0040] As Figure 1-10 shown, a bistable flexible machine gripper based on water bomb origami structure includes a rigid connecting piece 2, a gripping unit 3 with bistable characteristics, and a driving unit 1 for driving the gripping unit; the rigid connecting piece 2 is connected to the gripping unit 3 at one end and to the driving unit 1 at the other end, the gripping unit 3 is designed as a water bomb origami structure, including a water bomb origami unit 301 and four clamping jaws 302. The water bomb origami unit 301 has bistable characteristics.

[0041] The driving unit 1 fixed on the gripping unit 3 is driven by a vacuum pump to provide negative pressure, which drives the piston rod 103 of the driving unit 1 to move upward, and the water bomb origami unit 301 is folded to make the clamping jaws 302 achieve gripping; the vacuum pump provides positive pressure to drive the piston rod 103 of the driving unit to move downward, and the water bomb origami unit 301 is unfolded to make the clamping jaws 302 achieve releasing objects.

[0042] The gripping unit 3 adopts a multi-layer laminated structure, the crease has good elasticity, and can maintain a specific shape under different pressures, and the carbon fiber interlayer at the panel increases the rigidity and reduces the stress at the panel. The water bomb origami unit 301 is designed to have two stable states of upward protrusion and downward protrusion to adapt to active and passive gripping modes. Under the action of no external force, the vertex of the water bomb origami unit is naturally higher than the crease, forming an upward protruding shape, which is suitable for active gripping mode. Under the action of no external force, the vertex of the water bomb origami unit is naturally lower than the crease, forming a downward protruding shape, which is suitable for passive gripping mode.

[0043] The upper end of the sleeve 105 is connected to the vacuum pump, and the lower end is connected to the piston rod 103. A sealing structure is designed inside the sleeve to ensure airtightness under negative or positive pressure. A rubber sealing ring or similar material is used to ensure that the connection between the sleeve and the piston rod is leak-proof under negative or positive pressure. The sleeve and the piston rod are secured by a slot to ensure stability and reliability during movement. The driving force of the drive unit is provided by a vacuum pump and an air compressor. The vacuum pump provides negative pressure in the active grasping mode, driving the piston rod 103 upward to retract the water bullet origami unit. The air compressor provides positive pressure when releasing the object, driving the piston rod 103 downward to deploy the water bullet origami unit. The rigid connector 2 comprises a base 4, a connecting rod 5, and a connecting hinge 201. The connecting hinge 201 consists of four small parts: a connecting seat 8, a steering sleeve 6, a bayonet pin 7, and a retaining ring 9. These four small parts are integrated into a compact module, ensuring coordinated operation and convenient maintenance.

[0044] Active grasping: Start the vacuum pump to generate negative pressure, drive the piston rod to move upward, and the water bomb origami unit will collapse to achieve grasping.

[0045] Passive grasping: When an object touches the center point of the water bullet origami unit, it only needs to provide a sudden change force on the center point of the water bullet origami unit to make the grasping unit deform from one steady state to another. The water bullet origami unit will collapse and grasping will be achieved. The response speed is fast and the structure is simple.

[0046] Release the object: Start the air compressor to generate positive pressure, which drives the piston rod downward, and the water bomb origami unit unfolds to achieve release.

[0047] Through the above specific embodiments, the grasping device of the present invention can flexibly operate in active and passive modes to achieve precise grasping and releasing of objects.

[0048] In addition, due to its bistable characteristics, the water bullet origami unit can exhibit good flexibility and can adapt to complex, irregular and variable objects; the grasping unit is set as a water bullet origami structure so that the gripper forms a wrapped shape after bending, which is convenient for wrapping and grasping objects, thereby improving the grasping ability. At the same time, the water bullet origami structure has a high concealment and is suitable for exploration and capture operations in special occasions.

[0049] The gripping unit is designed as a multi-layer structure, comprising an upper, middle, and lower layer. The upper and lower layers are made of PET (polyethylene terephthalate), while the middle layer is made of woven carbon fiber epoxy resin prepreg. PET film has high tensile strength, flexural strength, and impact strength, as well as good wear and fatigue resistance, making it suitable for use as both the upper and lower crease materials. The middle layer, made of a woven carbon fiber epoxy resin composite, improves the stiffness of the bistable laminate.

[0050] The bistable gripper of the present invention has the advantages of simple structure, easy production and fast response speed. It can realize two modes of active grasping and passive grasping, and is suitable for various application scenarios, such as automated operations and task execution in special environments.

Claims

1. A method for manufacturing a bistable gripper based on a water-elastic origami structure, characterized in that: The bistable gripper comprises: a driving unit (1), a rigid connecting member (2), and a grasping unit (3); the rigid connecting member (2) is used for connecting the grasping unit (3) and the driving unit (1); the grasping unit (3) comprises a water bullet origami unit (301) and clamping claws (302) arranged around the water bullet origami unit (301); under the drive of the driving unit (1), the rigid connecting member (2) drives the water bullet origami unit (301) to expand and retract, thereby driving the clamping claws (302) to grasp and release; The preparation method comprises the following steps: Step 1: The gripping unit is made of a woven carbon fiber epoxy resin composite material. The woven carbon fiber epoxy resin composite prepreg is cut into eight isosceles triangles and eight obtuse triangles using a cutting machine. The eight isosceles triangles form a water bullet origami unit, and the eight obtuse triangles form four grippers. The water bullet origami unit and grippers are prepared using an autoclave process. Step 2: Attach 3M tape to the PET film and fix the cured woven carbon fiber epoxy composite grabbing unit to the PET film according to the drawing, leaving a 2mm gap between the sides of each triangle. Cover the first PET film with the carbon fiber layer with a second PET film with 3M tape to obtain a multilayer structure. Step 3: Use a laser cutting machine to cut out the plane shape of the multi-layer structure of the grabbing unit, make dotted line cuts at the creases, and continuously cut the outer contour of the four-pointed star. The outer contour cutting size is larger than the woven carbon fiber epoxy resin composite material layer, so the laser cutting layer does not contain the woven carbon fiber epoxy resin composite material layer, and the cut grabbing unit is pre-folded; In step 3, the two layers of PET film with 3M tape attached are cut by laser, and the materials at the cut are melted and stuck together; Step 4: Use 3D printing technology to print the rigid connector and drive unit of resin material; Step 5: Connect the drive unit and the gripping unit through rigid connectors to assemble the gripper. Step 6: Connect the upper end of the sleeve and the air drive equipment through the polyester PU tube.

2. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 1, characterized in that: The drive unit (1) comprises a sleeve (105), a piston (102) and a piston rod (103); the upper end of the sleeve (105) is connected to a polyester PU tube (101) of an air drive device; the piston (102) is slidably arranged in the sleeve (105); the top of the piston (102) is fixedly connected to the piston (102); and the bottom of the piston rod (103) is connected to the top of the water bullet origami unit (301).

3. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 2, characterized in that: The bottom end of the piston rod (103) is a frustum, which is engaged with the vertex of the water bullet origami unit (301).

4. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 1, characterized in that: The water bomb origami unit (301) comprises a vertex and eight folds, wherein the eight folds include four mountain folds and four valley folds, and the eight folds are completely symmetrical and can be completely unfolded into a plane.

5. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 1, characterized in that: The gripping unit (3) is folded from a plane into a three-dimensional structure, and its plane is formed by pasting three layers of materials, wherein the upper and lower layers are PET films, and the middle layer is a woven carbon fiber epoxy resin composite material plate. The PET film and the woven carbon fiber epoxy resin composite material plate are connected by 3M tape, so the layers from top to bottom are PET film, 3M tape, woven carbon fiber epoxy resin composite material plate, 3M tape, and PET film.

6. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 2, characterized in that: The rigid connecting member (2) comprises a base (4), a connecting rod (5) and a connecting hinge (201); the connecting hinge (201) comprises a connecting seat (8), a steering sleeve (6), an annular buckle (7) and a buckle base (9); the steering sleeve (6) is movably arranged on the connecting seat (8) via the annular buckle (7) and the buckle base (9); the connecting seat (8) is fixed to the outside of the driving unit (1); and the connecting seat (8) is fixed to the water bomb origami unit (301); one end of the connecting rod (5) is connected to the connecting hinge (201), and the other end is connected to the base (4); and the base (4) is fixed to the outside of the sleeve (105).

7. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 6, characterized in that: The water bullet origami unit (301) has a bistable characteristic, and the bistable gripper can realize two grasping modes: active grasping and passive grasping. In the active grasping mode, the water bullet origami unit bulges upward, that is, the apex of the water bullet origami unit is higher than the fold, and the vacuum pump connected to the upper end of the sleeve (105) provides negative pressure, driving the piston rod (103) to move upward, and the water bullet origami unit is retracted, so that the grasping unit can grasp; in the passive grasping mode, the water bullet origami unit bulges downward, that is, the apex of the water bullet origami unit is lower than the fold, and when the grasped object touches the center point of the water bullet origami unit, the contact force causes the apex of the water bullet origami unit to move upward to the stable transition critical value, triggering the bistable transition of the water bullet origami unit, and the water bullet origami unit is retracted, so as to realize grasping.

8. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 2, characterized in that: The sleeve (105) and the piston rod (103) are made of resin material by 3D printing, and the piston (102) is made of rubber material.

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