Bistable gripper based on water elastic paper folding structure and manufacturing method of bistable gripper

Abstract

The invention discloses a bistable gripper based on a water elastic paper folding structure and a manufacturing method of the bistable gripper. The bistable gripper comprises a driving unit, a rigid connecting piece and a gripping unit. The rigid connecting piece is used for connecting the grabbing unit and the driving unit; the grabbing unit comprises a water bomb paper folding unit and clamping jaws arranged on the periphery of the water bomb paper folding unit, the water bomb paper folding unit is driven by the driving unit to be unfolded and folded through a rigid connecting piece, and then grabbing and releasing of the clamping jaws are driven. The method has wide applicability and remarkable economic benefits in practical application; a novel efficient, low-cost and multifunctional grabbing solution can be provided for the technical field of soft robots.

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-elastic origami structure and a manufacturing method thereof. Background Art

[0002] The bistable gripper based on the water-elastic origami structure is a new type of soft robot technology. This structure has two stable states: the initial state and the grasping state. Under the action of external force, the structure can quickly switch from the initial state to the grasping state to achieve fast passive grasping. The bistable gripper based on the water-elastic origami structure can achieve two grasping modes: fast passive grasping and fast active grasping. The bistable gripper based on the water-elastic origami structure can be applied to space capture systems to grasp fast-moving objects, and can also be applied to the manipulator of industrial robots to quickly and repeatedly grasp various fragile objects. This gripper has broad application prospects in automated operations and task execution in special environments due to its controllable grasping mode, controllable response speed, and low cost. In summary, the bistable gripper based on the water-elastic origami structure provides an efficient, flexible and cost-effective solution for the field of soft robots through its unique bistable characteristics and multiple grasping modes. However, the current soft grippers are slow in practical applications, and achieving high-speed gripping is a challenge. Although the programmable bistable actuator based on the foldable adjustable bistable structure can achieve fast and diversified grasping, how to further improve the response speed and grasping efficiency is still a problem that needs to be solved. Therefore, in view of the above technical problems, 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 making the same. The design of the gripper aims to solve the problem of a single grasping mode and complex manufacturing in the prior art, and provides a bistable gripper with a simple structure, convenient manufacturing, and fast response speed, which can maintain grasping ability without external force, and realize two modes of active grasping and passive grasping. The bistable gripper of the present invention not only improves the flexibility and adaptability of grasping through its unique design, but also reduces energy consumption, thereby broadening the scope of application 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-elastic origami structure comprises: a driving unit, a rigid connecting piece, and a grasping unit; the rigid connecting piece is used for connecting the grasping unit and the driving unit; the grasping unit comprises a water-elastic origami unit and clamps arranged around the water-elastic origami unit, and under the drive of the driving unit, the water-elastic origami unit is driven to expand and collapse through the rigid connecting piece, thereby driving the grasping and releasing of the clamps.

[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 arranged 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 snap-fitted with the vertex of the water bomb 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 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-elastic 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-elastic origami unit protrudes upward, that is, the top of the water-elastic 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-elastic origami unit is retracted, so that the grasping unit can grasp; in the passive grasping mode, the water-elastic origami unit protrudes downward, that is, the top of the water-elastic origami unit is lower than the crease, and when the grasped object touches the center point of the water-elastic origami unit, the contact force causes the top of the water-elastic origami unit to move upward to the critical value of the steady-state transition, triggering the bistable transition of the water-elastic origami unit, and the water-elastic origami unit is retracted to realize 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 grabbing unit is made of a braided carbon fiber epoxy resin composite material. The braided carbon fiber epoxy resin composite material prepreg is cut into eight isosceles triangles and eight obtuse triangles by a cutting machine. The eight isosceles triangles form a water-elastic origami unit, and the eight obtuse triangles form four grippers. The water-elastic origami unit and the gripper are prepared by an autoclave process;

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

[0016] Step 3: Cut out the plane shape of the multi-layer structure grabbing unit by a laser cutting machine, make dotted line cutting at the crease, 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 pre-fold the cut grabbing unit;

[0017] In the step 3, after the two layers of PET films attached with 3M tape are cut by laser, 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 driving unit and the grabbing unit through a rigid connector to assemble the entire grabber;

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

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

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

[0023] 2) Fast response speed: Through pneumatic drive, the gripper of the present invention can achieve fast response, rapid 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 to 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 innovative in technology, but also has wide applicability and significant economic benefits in practical applications. Through the implementation of the present invention, a new type of efficient, low-cost, and multifunctional grasping solution can be provided for the field of soft robotics technology. 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 a grabbing 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 It is a schematic diagram of the grasping state of the grasping unit of the present invention;

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

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

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

[0036] Fig. 9 It is a structural diagram of a driving unit of a bistable gripper of the present invention;

[0037] Fig.10 It is a schematic diagram of a multi-layer structure of a bistable gripper of the present invention;

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

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] like Figure 1-10 As shown, a bistable flexible robot gripper based on a water-elastic origami structure includes a rigid connector 2, a gripping unit 3 with a bistable characteristic, and a driving unit 1 for driving the gripping unit; one end of the rigid connector 2 is connected to the gripping unit 3, and the other end is connected to the driving unit 1, and the gripping unit 3 is set as a water-elastic origami structure, including a water-elastic origami unit 301 and four grippers 302. The water-elastic origami unit 301 has a bistable characteristic.

[0041] The driving unit 1 fixed on the grasping unit 3 is provided with negative pressure by the vacuum pump, which drives the piston rod 103 of the driving unit 1 to move upward, and the water bullet origami unit 301 is retracted, so that the clamp 302 can grasp the object; the vacuum pump provides positive pressure, which drives the piston rod 103 of the driving unit to move downward, and the water bullet origami unit 301 is unfolded, so that the clamp 302 can release the object.

[0042] The gripping unit 3 adopts a multi-layer laminated structure, and the crease has good elasticity, which can maintain a specific shape under different pressures. The carbon fiber interlayer at the panel increases rigidity and reduces stress at the panel. The water-elastic origami unit 301 is designed to have two stable states of upward protrusion and downward protrusion to adapt to active and passive gripping modes. In the absence of external force, the vertex of the water-elastic origami unit is naturally higher than the crease, forming an upward protrusion shape, which is suitable for active gripping mode. In the absence of external force, the vertex of the water-elastic origami unit is naturally lower than the crease, forming a downward protrusion 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 the sealing performance under negative pressure or positive pressure. A rubber sealing ring or similar material is used to ensure that the connection between the sleeve and the piston rod will not leak under negative pressure or positive pressure. The sleeve and the piston rod are fixed by a card 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 is used to provide negative pressure in the active grasping mode to drive the piston rod 103 to move upward so that the water bullet origami unit is folded. The air compressor is used to provide positive pressure when the object needs to be released, driving the piston rod 103 to move downward so that the water bullet origami unit is unfolded. The rigid connector 2 includes a base 4, a connecting rod 5 and a connecting hinge 201. The connecting hinge 201 includes four small parts, including a connecting seat 8, a steering sleeve 6, a bayonet pin 7, and a snap ring 9; these four small parts are integrated in a compact module to ensure the coordination between the components and the convenience of 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, you only need to provide a sudden change force to 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 to achieve grasping. 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 to move downward, and the water bomb origami unit unfolds to achieve release.

[0047] Through the above specific implementations, the grasping device of the present invention can flexibly work in active and passive modes to achieve accurate 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 configured as a multi-layer structure, including an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are configured as PET (polyethylene terephthalate) materials, and the middle layer is configured as a woven carbon fiber epoxy resin prepreg material. PET film has high tensile strength, bending strength and impact strength, as well as good wear resistance and fatigue resistance, and is suitable for configuring the upper and lower layers as crease materials at the same time; and configuring the middle layer as a woven carbon fiber epoxy resin composite material can improve the stiffness of the bistable laminate.

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

Claims

1. A bistable gripper based on a water-elastic origami structure, characterized in that: include: 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-elastic origami unit (301) and clamps (302) arranged around the water-elastic origami unit (301); under the drive of the driving unit (1), the rigid connecting member (2) drives the water-elastic origami unit (301) to expand and retract, thereby driving the clamps (302) to grasp and release.

2. The bistable gripper based on the water spring origami structure according to claim 1 is characterized in that: The driving 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 a water bomb origami unit (301).

3. The bistable gripper based on the water spring origami structure according to claim 1 is characterized in that: The bottom end of the piston rod (3) is a frustum, which is engaged with the vertex of the water bomb origami unit (301).

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

5. The bistable gripper based on the water spring origami structure according to claim 1 is 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 bistable gripper based on the water spring origami structure according to claim 1 is 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) through 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 bistable gripper based on the water spring origami structure according to claim 1 is characterized in that: The water-elastic origami unit (301) has a bistable characteristic, and the bistable gripper can realize two grasping modes, namely, active grasping and passive grasping. In the active grasping mode, the water-elastic origami unit bulges upward, namely, the apex of the water-elastic origami unit is higher than the fold, and the vacuum pump connected to the upper end of the sleeve (105) provides negative pressure to drive the piston rod (103) to move upward, and the water-elastic origami unit is retracted, so that the grasping unit can grasp; in the passive grasping mode, the water-elastic origami unit bulges downward, namely, the apex of the water-elastic origami unit is lower than the fold, and when the grasped object touches the center point of the water-elastic origami unit, the contact force causes the apex of the water-elastic origami unit to move upward to the critical value of the steady-state transition, thereby triggering the bistable transition of the water-elastic origami unit, and the water-elastic origami unit is retracted to realize grasping.

8. The bistable gripper based on the water spring origami structure according to claim 2 is 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.

9. A method for manufacturing a bistable gripper based on a water-elastic origami structure, characterized in that: The following steps are involved: Step 1: The grabbing unit is made of a braided carbon fiber epoxy resin composite material. The braided carbon fiber epoxy resin composite material prepreg is cut into eight isosceles triangles and eight obtuse triangles by a cutting machine. The eight isosceles triangles form a water-elastic origami unit, and the eight obtuse triangles form four grippers. The water-elastic origami unit and the gripper are prepared by an autoclave process; Step 2: Attach 3M tape to the PET film, fix the cured woven carbon fiber epoxy resin composite grabbing unit on the PET film according to the drawing, leave a 2mm gap between the sides of each triangle, and cover the second PET film with 3M tape on the first PET film with the carbon fiber layer to obtain a multilayer structure; Step 3: Cut out the plane shape of the multi-layer structure grabbing unit by a laser cutting machine, make dotted line cutting at the crease, 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 pre-fold the cut grabbing unit; Step 4: Use 3D printing technology to print the rigid connector and drive unit of resin material; Step 5: Connect the driving unit and the grabbing unit through a rigid connector to assemble the entire grabber; Step 6: Connect the upper end of the sleeve and the air drive equipment through a polyester PU tube.

10. The method for manufacturing a bistable gripper based on a water-elastic origami structure according to claim 9, characterized in that: In the step three, after the two layers of PET films attached with 3M tape are cut by laser, the materials at the cut are melted and stuck together.

Images