A magnetically driven soft gripper based on a foldable structure

Abstract

The present invention discloses a magnetically driven soft gripper based on a foldable structure, comprising a gripper body, a magnetic field control part and an end connection part, wherein the gripper body comprises paramagnetic regions at upper and lower ends and a ferromagnetic region connected between the paramagnetic regions at both ends, the magnetic field control part comprises a vertical spiral coil, an annular spiral coil, a permanent magnet and a support system, and the end connection part comprises a single-axis rotation joint; the upper end of the permanent magnet is connected to the vertical spiral coil, the outer wall of the upper end of the permanent magnet is connected to the upper paramagnetic region of the gripper body, and the lower end of the permanent magnet is connected to the support system; the annular spiral coil is installed on the support system, and the upper end of the vertical spiral coil is connected to the single-axis rotation joint. The present invention has the advantages of fast response speed, stable performance, simple control, etc., and can safely capture target organisms or efficiently grasp objects. The present invention helps to solve the shortcomings of the end effector of the robot, such as single motion mode, large weight, and poor passive adaptive ability.

Description

Technical Field

[0001] The present invention belongs to the field of end effectors of intelligent robots, and in particular relates to a magnetically driven soft gripper based on a foldable structure. Background Art

[0002] In recent years, with the development of the times, intelligent robots have gradually been applied to various fields of production and life, and the flexibility, adaptability and response efficiency of the robot's end effector have become key factors affecting the robot's working performance.

[0003] Traditional robot end effectors are mostly designed for structured environments and are made of rigid materials with poor elastic deformation capabilities. They are generally driven by motors, pneumatics, hydraulics, etc. Although they have excellent stability and reliability, they have disadvantages such as single motion mode, heavy weight, and poor passive adaptive ability. They cannot meet the performance requirements of lightweight, flexible, agile, and non-destructive grasping in special working environments, such as industrial fragile object grasping and marine biological sampling. In order to overcome the working defects of traditional rigid end effectors in terms of materials, structures, and drive methods, the development of intelligent materials, multi-degree-of-freedom structures, and efficient drive methods has become a new way to achieve lightweight and flexible design of intelligent robot end effectors. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a design scheme of a magnetically driven soft gripper based on a foldable structure, so as to improve the adaptability, reliability and response efficiency of the robot end effector operation, while meeting the lightweight requirements of the end effector.

[0005] The object of the present invention is achieved through the following technical solutions: A magnetically driven soft gripper based on a foldable structure, comprising a gripper body, a magnetic field control part and an end connection part, wherein the gripper body comprises paramagnetic regions at upper and lower ends and a ferromagnetic region connected between the paramagnetic regions at both ends, the magnetic field control part comprises a vertical spiral coil, a ring-shaped spiral coil, a permanent magnet and a support system, and the end connection part comprises a single-axis rotation joint;

[0006] The upper end of the permanent magnet is connected to the vertical spiral coil, and the upper paramagnetic region of the gripper body is connected to the outer wall of the upper end of the permanent magnet at the connection, and the lower end of the permanent magnet is connected to the support system; the annular spiral coil is installed on the support system, and the upper end of the vertical spiral coil is connected to the single-axis rotation joint.

[0007] Furthermore, the main body of the gripper is made of paper-based flexible material based on the Miura origami structure. A laser engraving machine cuts mountain crease grooves and valley crease grooves on the paper surfaces on both sides respectively. After folding and overlapping and bonding of the two side boundaries, the gripper is formed. It has flexible and expandable characteristics, providing the necessary flexible deformation conditions for the gripper to achieve biological capture or object grasping actions.

[0008] Furthermore, a pre-treatment method is selected for the paramagnetic region and the ferromagnetic region, that is, before the gripper body is folded and formed, the specific treatment method is: according to the crease dividing line of the two regions, the paramagnetic region is only sprayed with a thin waterproof layer, and the ferromagnetic region is first coated with a NdFeB-PDMS colloidal preparation with a mass ratio of 2:1 on the surface, and then sprayed with a thin waterproof layer.

[0009] Furthermore, the support system is composed of a sleeve, a guide rail, a fixed support rod, and a telescopic support rod; the lower end of the permanent magnet is connected to the upper part of the sleeve, and the two move synchronously on the guide rail;

[0010] The sleeve is a thin-walled cylindrical component that can slide along the guide rail, with the upper end connected to the lower end of the permanent magnet, and three hinge interfaces arranged on the side wall, which are respectively hinged to one end of the three telescopic support rods; when the permanent magnet is subjected to the magnetic repulsion force of the vertical solenoid, the "permanent magnet-sleeve-upper part of the gripper" moves downward along the guide rail as a whole;

[0011] The guide rail is a hollow member with a circular cross section, and a power supply line of a ring-shaped spiral coil is arranged inside, the upper end of which is connected to the permanent magnet through a sleeve, and the lower end is fixedly connected to the end of the fixed support rod;

[0012] The fixed support rod is a cylindrical hollow member, three of which are evenly arranged in the annular direction, and a power supply line of the annular spiral coil is arranged inside. Both ends of the fixed support rod are rigidly fixed and constrained, one end is fixed to the lower end of the guide rail, and the other end is fixed to the annular spiral coil;

[0013] The telescopic support rods are nested telescopic components, three of which are evenly arranged in the annular direction, and both ends of the telescopic support rods are flexibly hinged and constrained; one end is hinged to the sleeve, and the other end is hinged to the annular spiral coil.

[0014] Furthermore, the end connection part also includes a pulse power supply interface and a connecting flange; the pulse power supply interface and the connecting flange are installed on a single-axis rotation joint; and the connecting flange is used to connect a robot arm.

[0015] The magnetically driven soft gripper based on a foldable structure proposed in the present invention can use a programmed pulse power supply to generate a strong magnetic field in the vertical spiral coil and the annular spiral coil. The direction of the magnetic field depends on the motion mode of the gripper. Under the action of the magnetic repulsive force (attractive force), the root of the gripper body moves downward (upward) with the permanent magnet, and the ferromagnetic region of the gripper body opens (tightens), thereby enabling the soft gripper of the present invention to capture organisms or grasp objects.

[0016] The magnetically driven soft gripper based on a foldable structure proposed in the present invention has the advantages of stable performance, simple control, strong adaptability, and light weight. The invention of this design helps to solve the shortcomings of the end effector of the intelligent robot, such as a single motion mode, heavy weight, and poor passive adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the magnetically driven soft gripper of the present invention;

[0018] Figure 2 It is a folding diagram and a partial engraving schematic diagram based on the Miura origami structure design of the present invention;

[0019] Figure 3 It is a schematic cross-sectional view of the structure of the magnetically driven soft gripper of the present invention;

[0020] Figure 4 It is a schematic diagram of the unfolded state of the magnetically driven soft gripper of the present invention;

[0021] Figure 5 It is a schematic diagram of the magnetic field control part and the end connection part of the magnetically driven soft gripper of the present invention.

[0022] In the figure: gripper body 1; paramagnetic region 100; ferromagnetic region 101; mountain fold groove 102; valley fold groove 103; magnetic field control part 2; vertical spiral coil 200; annular spiral coil 201; permanent magnet 202; support system 203; sleeve 2030; guide rail 2031; fixed support rod 2032; telescopic support rod 2033; end connection part 3; single-axis rotation joint 300; pulse power supply interface 301; connecting flange 302. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0024] like Figure 1-Figure 5As shown, the present invention provides a magnetically driven soft gripper based on a foldable structure, including a gripper body 1, a magnetic field control part 2 and an end connection part 3, the gripper body 1 includes a paramagnetic region 100, a ferromagnetic region 101, a mountain fold groove 102 and a valley fold groove 103, the magnetic field control part 2 includes a vertical spiral coil 200, a ring spiral coil 201, a permanent magnet 202 and a support system 203, and the end connection part 3 includes a single-axis rotation joint 300, a pulse power interface 301 and a connecting flange 302.

[0025] The magnetically driven soft gripper based on a foldable structure has a gripper body 1 made of a paper-based flexible material. A laser engraving machine is used to cut mountain fold grooves 102 and valley fold grooves 103 with a depth of 60% to 70% of the total thickness of the paper from the outside to the inside on both sides of the paper. After folding and overlapping and bonding the boundaries on both sides, it is formed. It has flexible foldable characteristics, providing the necessary flexible deformation conditions for the gripper to achieve biological capture and object grasping actions.

[0026] The foldable structure of the gripper body 1 is designed based on the Miura origami structure. Figure 2 The crease diagram and its partial engraving schematic diagram based on the Miura origami structure design of the present invention are explained as an example. Taking a single origami unit as an example, for the convenience of introduction, the present invention introduces a coordinate system of length direction x, width direction y, and height direction z. H is the total length of a single origami unit in the y direction, in mm, h is the length of the smaller fold surface of a single origami unit in the y direction, in mm, and α is the fan angle between adjacent mountain folds and valley folds in a single origami unit. In a single origami unit, the four fold surfaces are symmetrical about the y-axis, and the design parameters are H:h=3:1, α=75°. The number of linear arrangements of a single origami unit in the x-direction is [0.85H], and the number of linear arrangements in the y-direction is [150° / (90°-α)]. This parameter design determines the foldable flexibility of the gripper body 1 structure, where [*] is an integer function.

[0027] The paramagnetic region 100 of the gripper body 1 is distributed at the upper and lower ends of the gripper body 1, and the ferromagnetic region 101 is distributed in the middle of the gripper body 1 and connected to the paramagnetic regions 100 at both ends. The paramagnetic region 100 and the ferromagnetic region 101 are pre-treated, that is, they are folded and formed before the gripper body. The specific treatment method is: according to the crease boundary of the two regions, the former is only sprayed with a thin waterproof layer, and the latter is first coated with a NdFeB-PDMS (mass ratio of 2:1) gel preparation on the surface, and then sprayed with a thin waterproof layer. After the above process is completely formed, the ferromagnetic region 101 is subjected to a discrete magnetization treatment to realize the directional design of the magnetic domain distribution in the region. When a pulse current is passed through the annular spiral coil 201, the ferromagnetic region 101 moves to expand or retract.

[0028] The upper end of the permanent magnet 202 is connected to the vertical spiral coil 200, and the outer wall of the upper end of the permanent magnet 202 is bonded to the edge of the paramagnetic region 100 on the upper part of the gripper body 1. The two can slide synchronously along the guide rail 2031, and the lower end of the permanent magnet 202 is connected to the support system 203. The annular spiral coil 201 is installed on the support system 203, and the upper end of the vertical spiral coil 200 is connected to the uniaxial rotation joint 300. When the permanent magnet 202 slides along the guide rail 2031 due to the magnetic field force generated when the vertical spiral coil 200 is passed through a pulse current, the upper part of the gripper body 1 is pulled by the permanent magnet 202 to move synchronously.

[0029] like Figure 5 As shown, the support system 203 is composed of a sleeve 2030, a guide rail 2031, a fixed support rod 2032 and a telescopic support rod 2033. The lower end of the permanent magnet 202 is connected to the upper part of the sleeve 2030, and the two move synchronously on the guide rail 2031; the sleeve 2030 is a thin-walled cylindrical component, which can slide along the guide rail 2031, and the upper end is connected to the lower end of the permanent magnet 202. Three hinge interfaces are arranged on the side wall, which are respectively hinged to one end of the three telescopic support rods 2033; when the permanent magnet is subjected to the magnetic repulsion force of the vertical solenoid, the "permanent magnet-sleeve-upper part of the gripper" moves downward along the guide rail as a whole;

[0030] The guide rail 2031 is a hollow member with a circular cross section, in which a power supply line of the annular spiral coil 201 is arranged, the upper end of which is connected to the permanent magnet 202 through the sleeve 2030, and the lower end is fixedly connected to the end of the fixed support rod 2032;

[0031] The fixed support rod 2032 is a cylindrical hollow component with three rods evenly arranged in the annular direction. The power supply line of the annular spiral coil 201 is arranged inside. The two ends of the fixed support rod 2032 are rigidly fixed constraints. Specifically, one end is fixed to the lower end of the guide rail 2031 and the other end is fixed to the annular spiral coil 201.

[0032] The telescopic support rod 2033 is a nested telescopic member, with three rods evenly arranged in the annular direction, and both ends are flexibly hinged. Specifically, the telescopic support rod 2033 has the ability to telescope along the rod axis and the ability to rotate around the rod axis at the end to adapt to the sliding movement of the permanent magnet 202. One end of the telescopic support rod 2033 is hinged to the sleeve 2030, and the other end is hinged to the annular spiral coil 201.

[0033] The pulse power supply interface 301 and the connection flange 302 are installed on the single-axis rotation joint 300; the connection flange 302 is used to connect the robot arm.

[0034] by Figure 3 , Figure 4The working principle of the magnetically driven soft gripper is explained as an example. By inputting a programmed pulse current into the pulse power interface 301, the vertical spiral coil 200 generates a strong magnetic field in the same direction as the magnetic field of the permanent magnet 202. The permanent magnet 202 is driven by the magnetic repulsion force to drive the upper part of the gripper body 1 to move downward along the guide 2031. At the same time, the annular spiral coil 201 generates a strong magnetic field in the same direction as the magnetic field of the magnetized ferromagnetic region 101. The ferromagnetic region 101 moves outward under the magnetic repulsion force. Under the interaction of the two movements, the gripper is in an unfolded state. When the magnetic field is removed, the gripper can restore the folded state with the help of the self-contraction of the foldable structure. A reverse current can also be input to accelerate the folding process, so that the soft gripper of the present invention can achieve the action of capturing or grabbing. The magnetically driven soft gripper of the present invention has the advantages of fast response speed, stable performance, simple control, etc., and can safely capture the target organism or efficiently grab objects. The invention of this design helps to solve the shortcomings of the end effector of the intelligent robot, such as a single motion mode, a large weight, and poor passive adaptive ability.

[0035] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A magnetically driven soft gripper based on a foldable structure, characterized in that: The gripper body (1) comprises a gripper body (1), a magnetic field control part (2) and an end connection part (3), wherein the gripper body (1) comprises a paramagnetic region (100) at the upper and lower ends and a ferromagnetic region (101) connected between the paramagnetic regions (100) at the two ends, the magnetic field control part (2) comprises a vertical spiral coil (200), a ring-shaped spiral coil (201), a permanent magnet (202) and a support system (203), and the end connection part (3) comprises a single-axis rotation joint (300); the gripper body (1) is a paper-based flexible material, based on the Miura origami structure, and a mountain fold line groove (102) and a valley fold line groove (103) are cut out on the paper surface on both sides by a laser engraving machine, and the paper surface is folded and the boundaries of both sides are overlapped and bonded to form the material; The upper end of the permanent magnet (202) is connected to the vertical spiral coil (200), the upper end outer wall of the permanent magnet (202) at the connection is connected to the upper end paramagnetic region (100) of the gripper body (1), and the lower end of the permanent magnet (202) is connected to the support system (203); the annular spiral coil (201) is installed on the support system (203), and the upper end of the vertical spiral coil (200) is connected to the single-axis rotation joint (300); The support system (203) is composed of a sleeve (2030), a guide rail (2031), a fixed support rod (2032), and a telescopic support rod (2033); the lower end of the permanent magnet (202) is connected to the upper part of the sleeve (2030), and the two move synchronously on the guide rail (2031); The sleeve (2030) is a thin-walled cylindrical component that can slide along the guide rail (2031), with its upper end connected to the lower end of the permanent magnet (202), and three hinge interfaces arranged on the side wall, which are respectively hinged to one end of three telescopic support rods (2033); when the permanent magnet is subjected to the magnetic repulsive force of the vertical solenoid, the "permanent magnet-sleeve-upper part of the gripper" moves downward along the guide rail as a whole; The guide rail (2031) is a hollow member with a circular cross section, and a power supply line of the annular spiral coil (201) is arranged inside, the upper end of which is connected to the permanent magnet (202) through a sleeve (2030), and the lower end is fixedly connected to the end of the fixed support rod (2032); The fixed support rod (2032) is a cylindrical hollow member, three of which are evenly arranged in the annular direction, and a power supply line of the annular spiral coil (201) is arranged inside. Both ends of the fixed support rod (2032) are rigidly fixed and constrained, one end is fixed to the lower end of the guide rail (2031), and the other end is fixed to the annular spiral coil (201); The telescopic support rod (2033) is a nested telescopic member, three of which are evenly arranged in a circumferential direction, and both ends of the telescopic support rod (2033) are flexibly hingedly constrained; one end of the telescopic support rod (2033) is hinged to the sleeve (2030), and the other end is hinged to the annular spiral coil (201); The vertical spiral coil (200) generates a strong magnetic field in the same direction as the magnetic field of the permanent magnet (202). The permanent magnet (202) is driven by the magnetic repulsion force to drive the upper part of the gripper body (1) to move downward along the guide rail (2031). At the same time, the annular spiral coil (201) generates a strong magnetic field in the same direction as the magnetic field of the magnetized ferromagnetic region (101). The ferromagnetic region (101) moves outwards due to the magnetic repulsion force. Under the interaction of the two movements, the gripper is in an unfolded state.

2. According to claim 1, a magnetically driven soft gripper based on a foldable structure is characterized in that: The paramagnetic region (100) and the ferromagnetic region (101) are pre-treated in a manner that is, they are folded and formed before the gripper body (1). The specific treatment method is as follows: according to the crease boundary between the two regions, the paramagnetic region (100) is only sprayed with a thin waterproof layer, and the ferromagnetic region (101) is first coated with a NdFeB-PDMS colloidal preparation with a mass ratio of 2:1 on the surface, and then sprayed with a thin waterproof layer.

3. The magnetically driven soft gripper based on a foldable structure according to claim 1, characterized in that: The end connection part (3) further comprises a pulse power interface (301) and a connection flange (302); the pulse power interface (301) and the connection flange (302) are mounted on the single-axis rotation joint (300); and the connection flange (302) is used for connecting to a robot arm.

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