Electromagnetic driving dexterous gripper based on soft beam buckling modal switching

Abstract

The application belongs to the technical field of robot end effector, and discloses an electromagnetic driving dexterous gripper based on soft beam bending mode switching, which comprises an outer frame, an upper part of which is provided with an electromagnetic driving module, and a lower part of which is fixed with an outer frame magnet, the electromagnetic driving module comprising an electromagnetic coil and a magnet; a soft beam driver, one end of which is connected with the magnet, and the other end of which is hingedly supported in the outer frame, the soft beam driver comprising a soft beam and a soft beam center magnet installed on the soft beam; and a finger, which is installed on the outer convex surface of the soft beam. The electromagnetic driving dexterous gripper provided by the application can pick up planar light and thin objects, and solves the problems that the existing rigid clamping jaw is difficult to pick up planar light and thin objects and the flexible clamping jaw has a slow dynamic response.

Description

Technical Field

[0001] This invention belongs to the field of robot end effector technology, specifically relating to an electromagnetically driven dexterous gripper based on soft beam buckling mode switching. Background Technology

[0002] In robot operation scenarios, traditional rigid industrial two-finger grippers have a very low success rate when grasping thin objects (such as cards, thin parts, etc.) that are close to the working plane. This is because they cannot achieve complex finger trajectories to meet the mutually coupled pressure and horizontal force required for grasping in real time.

[0003] While existing flexible grippers possess high deformation compliance, they mostly rely on pneumatic, hydraulic, or cable-driven motor networks, resulting in drawbacks such as complex drive system structures, large size, and slow dynamic response. Furthermore, their trajectories are simple, making it impossible to achieve complex and delicate movements with simple control signals. This makes them unsuitable for grasping tasks requiring transient explosive force and high-speed displacement, or complex finger trajectories. For example, Chinese patent CN121928595A discloses a flexible adaptive grasping finger and method based on an origami structure, relating to the field of robotic hand technology. This finger includes a base and at least two finger bodies. Each finger body includes a joint module, a finger segment module, and a connector. The joint module is a first hollow body formed by a triangular variant of the Yoshimura origami structure, with an air bladder on its dorsal side and a first guide hole on its ventral side. The finger segment module is a second hollow body. The connector is detachably connected to both the joint module and the finger segment module. A first cable passes through the first guide hole and connects to the ventral side of the last finger segment module, and a second cable passes through the second guide hole on the connector and connects to the middle position of the last finger segment module. And Chinese patent CN120985691A discloses a single-motor driven two-finger gripper with a flat clamping adaptive function, which relates to the field of industrial robot technology. A winding groove is integrally set at the center of the distal phalanx and hinged to the tip of the proximal phalanx via a front joint shaft. The proximal phalanx tip is hinged to the root phalanx tip via a rear joint shaft, and an outward turning torque is applied to the distal phalanx. A winding wheel is mounted on the rear joint shaft and equipped with a reset spring. A drive connector connects the distal phalanx tip and the edge of the winding wheel. A coupling rope connects the edge of the winding groove of the distal phalanx to the tip of the root phalanx. A linear motor drives a slider in the longitudinal groove in the middle of the base. Two mechanical fingers are symmetrically installed on both sides of the base. The drive rope passes through the middle of the slider and is fixed at both ends and wound around the winding wheel.

[0004] Therefore, how to solve the problems of existing rigid grippers being unable to pick up thin, flat objects and the slow dynamic response of flexible grippers are technical problems that urgently need to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide an electromagnetically driven dexterous gripper based on soft beam buckling mode switching, which can pick up planar thin objects and solve the problems of existing rigid grippers being unable to pick up planar thin objects and flexible grippers having slow dynamic response.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: An electromagnetically driven dexterous gripper based on soft beam buckling mode switching (a soft dexterous gripper utilizing electromagnetic drive combined with the snap-through characteristics of flexible soft beam buckling modes), comprising: The outer frame has an electromagnetic drive module at the top and a frame magnet fixed at the bottom. An electromagnetic drive module, comprising an electromagnetic coil and a magnet; A flexible beam actuator, one end of which is connected to a magnet, and the other end is hinged and supported in an outer frame, including a flexible beam and a central magnet of the flexible beam mounted on the flexible beam; The fingers are attached to the convex surface of the flexible beam.

[0007] In the initial stage, the central magnet of the flexible beam and the outer frame magnet are magnetically attracted, forcing the flexible beam to maintain the second buckling mode. The electromagnetic coil is energized to generate electromagnetic force to drive the magnet to produce axial displacement. When the accumulated transverse buckling force of the flexible beam overcomes the magnetic attraction between the central magnet of the flexible beam and the outer frame magnet, the flexible beam becomes unstable, releases strain energy and abruptly changes to the first buckling mode.

[0008] Furthermore, the outer frame has a hollow coolant cavity inside, and a coolant outlet and inlet on its surface.

[0009] Furthermore, the outer frame is provided with a guide channel that is isolated from the hollow coolant cavity, and the magnet is slidably fitted within the guide channel.

[0010] Furthermore, a smooth, uniformly radii guide cylindrical rod is coaxially fixed to the top of the magnet, a connecting device is fixed to the bottom of the magnet, and the upper end of the flexible beam is connected to the connecting device as a sliding hinge end.

[0011] Furthermore, the central magnet of the flexible beam is fixedly installed at the mid-span position of the flexible beam and is opposite to the position of the outer frame magnet, and the lower end of the flexible beam is hinged to the outer frame.

[0012] Furthermore, the rear end of the finger near the soft beam is made of high-rigidity PLA material, while the front end that contacts the target is made of soft PEBA material.

[0013] Furthermore, the magnets, the central magnet of the flexible beam, and the outer frame magnet are all neodymium iron boron magnets.

[0014] Furthermore, the outer frame is made of photosensitive resin; the flexible beam is made of TPU material.

[0015] The present invention also provides an application of the above-mentioned electromagnetically driven dexterous gripper in grasping flat, thin objects.

[0016] Compared with the prior art, the present invention has the following superior effects: The electromagnetically driven dexterous gripper provided by the present invention is an actuator with a highly integrated structure and extremely simple control logic. By deeply coupling the high-speed response characteristics of electromagnetic drive with the mechanical characteristics of buckling mode switching of flexible beam, the displacement input of a single simple geometric shape is transformed into a complex nonlinear motion trajectory, which solves the problems of existing rigid grippers being unable to pick up thin and light planar objects and the slow dynamic response of flexible grippers; and at the same time, it has an efficient thermal management system to ensure the operational stability of high-frequency operation. Attached Figure Description

[0017] Figure 1 An exploded view of the overall structure of the dexterous gripper provided in the embodiment; Figure 2 A three-dimensional modal switching state sequence diagram of the flexible beam actuator in the smart gripper during operation, provided for an embodiment; Figure 3 A partial enlarged view of the electromagnetic drive module and connecting device in the smart gripper provided in the embodiment; Figure 4 A side-view motion sequence diagram of the working mode of the flexible beam actuator in the smart gripper provided in the embodiment; wherein Figure 4 (a) in the image represents the palm-grabbing mode. Figure 4 (b) in the image represents the ejection mode to the outside of the palm. Figure 5 A side view sequence diagram of the operation sequence of the dexterous gripper picking up a thin object from a plane, provided in the embodiment; Figure 6 A side view sequence diagram of the operation sequence of the dexterous gripper ejecting a thin sheet object outward, provided in the embodiment. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0019] like Figure 1 and Figure 3 As shown, an electromagnetically driven dexterous gripper based on soft beam buckling mode jumping includes a photosensitive resin outer frame 1 fabricated using a 3D printing process. An electromagnetic drive module is mounted in the central region of the outer frame 1. Figure 3As shown, the electromagnetic coil 2 and the magnet 5 constitute the electromagnetic drive module. The outer frame 1 has a hollow coolant chamber inside, through which coolant circulates via an outlet and inlet on the side wall, actively dissipating heat from the electromagnetic coil 2. The outer frame cover 3 seals over the top of the outer frame 1, with two pre-drilled holes for the power supply wires of the electromagnetic coil 2 to be led out. The outer frame 1 has a guide channel isolated from the hollow coolant chamber, within which the magnet 5 (in this embodiment, a cylindrical magnet made of N52 neodymium iron boron magnet) slides. A smooth, uniformly radii guide cylindrical rod 4 is coaxially fixed to the top of the magnet 5 to reduce motion friction and limit radial offset; a connecting device 6 is fixed to the bottom of the magnet 5 for outputting electromagnetic force and providing hinged constraints for the flexible beam actuator 7.

[0020] like Figure 1 and Figure 2 As shown, the flexible beam actuator 7 consists of a TPU flexible beam 71 and an N52 flexible beam center magnet 72 located at its mid-span. The lower end of the flexible beam 71 is hinged to the support of the outer frame 1, and the upper end of the flexible beam 71 is connected to the connecting device 6 as a sliding hinge end to receive power input and accept the axial compression displacement of the magnet 5. An outer frame magnet 9 (in this embodiment, an N52 neodymium iron boron magnet) is fixed at the bottom of the outer frame 1 corresponding to the midpoint of the flexible beam. The finger 8 is mounted on the convex surface of the flexible beam 71 and is formed by 3D printing of two materials in one piece; the rear end of the finger 8 near the flexible beam is made of high-rigidity PLA material to ensure effective transmission of kinetic energy; the front end of the finger 8 that contacts the target is made of PEBA soft material to provide friction and the flexibility of the contact surface.

[0021] The working process of the dexterous gripper provided in this embodiment is as follows: When the flexible beam 71 is unstable under axial load, it has a second-order buckling mode and a first-order buckling mode. In the initial stage, the central magnet 72 of the flexible beam and the outer frame magnet 10 are magnetically attracted, forcing the flexible beam 71 to maintain the second-order buckling mode. The electromagnetic coil 2 is energized to generate electromagnetic force to drive the magnet 5 to produce axial displacement. When the lateral buckling force accumulated by the flexible beam 71 overcomes the magnetic attraction between the two magnets, the flexible beam 71 becomes unstable, releases strain energy and abruptly changes to the first-order buckling mode.

[0022] like Figure 4 (a) and Figure 5 As shown, the dynamic response of the gripper is based on the abrupt change from a higher-order buckling mode to a lower-order buckling mode in a slender flexible beam: In the inward gripping mode, during the initial stage of energization, the central magnet 72 of the flexible beam and the outer frame magnet 9 are magnetically attracted to each other, resulting in the lateral displacement of the midpoint of the flexible beam being strongly constrained. Under the continuous action of the electromagnetic force, the flexible beam 71 enters an "S"-shaped second-order buckling mode ( Figure 2And the deformation amplitude continues to increase. When triggered, the electromagnetic coil 2 is continuously energized, and the electromagnetic force drives the magnet 5 to push the flexible beam 71 downward via the connecting device 6. The accumulated elastic strain energy of the system is released, and the deformation of the flexible beam intensifies, causing a sharp increase in the lateral force at the midpoint. When the lateral force exceeds the magnetic attraction threshold of the two magnets, the central magnet 72 and the outer frame magnet 9 disengage and separate. Figure 2 In the process, the midpoint constraint of the soft beam failed, and the accumulated strain energy was violently released within about 20ms. The soft beam 71 became unstable and instantly transformed into a "C"-shaped first-order buckling mode. Figure 2 This transition process causes the finger 8 to generate extremely high deflection acceleration inward. The flexible fingertip of PEBA instantly rubs and pulls the thin object off the table from its state of pressing down on it, completing the clamping and picking action.

[0023] like Figure 4 (b) and Figure 6 As shown, the system supports a palm-out ejection mode. By slightly altering the initial deflection direction of the beam's end, the sudden jump direction after the soft beam accumulates strain energy is reversed. At the moment of release, deformation drives finger 8 to swing rapidly outward from the palm. While the pressure gradually decreases, it delivers a high horizontal impulse to thin objects such as flat playing cards, achieving precise removal or ejection tasks.

Claims

1. An electromagnetically driven dexterous gripper based on soft beam buckling mode switching, characterized in that, include: The outer frame (1) has an electromagnetic drive module on the upper part and an outer frame magnet (9) fixed on the lower part. The electromagnetic drive module includes an electromagnetic coil (2) and a magnet (5); The flexible beam actuator (7) is connected to a magnet (5) at one end and hinged to a frame (1) at the other end. It includes a flexible beam (71) and a flexible beam center magnet (72) mounted on the flexible beam (71). The finger (8) is installed on the outer convex surface of the flexible beam (71).

2. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 1, characterized in that, In the initial stage, the central magnet (72) of the soft beam and the outer frame magnet (9) are magnetically attracted, forcing the soft beam (71) to maintain the second buckling mode; the electromagnetic coil (2) is energized to generate electromagnetic force to drive the magnet (5) to produce axial displacement. When the lateral buckling force accumulated by the soft beam (71) overcomes the magnetic attraction between the central magnet (72) and the outer frame magnet (9), the soft beam (71) becomes unstable, releases strain energy and abruptly changes to the first buckling mode.

3. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 1, characterized in that, The outer frame (1) has a hollow coolant cavity inside and a coolant outlet and inlet on its surface.

4. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 3, characterized in that, The outer frame (1) is provided with a guide channel that is isolated from the hollow coolant cavity, and the magnet (5) is slidably fitted in the guide channel.

5. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 1, characterized in that, The top of the magnet (5) is coaxially fixed with a smooth guide cylindrical rod (4) of equal radius, and the bottom of the magnet (5) is fixed with a connecting device (6). The upper end of the flexible beam (71) is connected to the connecting device (6) as a sliding hinge end.

6. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 1, characterized in that, The central magnet (72) of the flexible beam is fixedly installed at the mid-span position of the flexible beam (71) and is opposite to the position of the outer frame magnet (9). The lower end of the flexible beam (71) is hinged to the outer frame (1).

7. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 1, characterized in that, The rear end of the finger (8) near the soft beam (71) is made of rigid PLA material, while the front end that contacts the target is made of soft PEBA material.

8. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 1, characterized in that, The magnet (5), the central magnet (72) of the soft beam, and the outer frame magnet (10) are all neodymium iron boron magnets.

9. The electromagnetically driven dexterous gripper based on soft beam buckling mode switching according to claim 1, characterized in that, The outer frame (1) is made of photosensitive resin; the soft beam (71) is made of TPU material.

10. The application of the electromagnetically driven dexterous gripper according to any one of claims 1-9 in grasping a flat, thin object.

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