An intelligent micro-gripper and a micro-memory gripper controlled by optical and magnetic coupling

Abstract

The present invention belongs to the field of flexible micro-robots, and specifically relates to an intelligent micro-gripper and a micro-memory gripper with combined optical and magnetic control. The intelligent micro-gripper includes a memory gripper, an optical signal generator, a magnetic field generating device, and a controller. Among them, the memory gripper is a micro-bionic gripper that can freely transform its own shape under the combined drive of optical and magnetic signals. The rest constitute related components that can generate specified optical and magnetic signals as needed. The memory gripper includes a base, multiple bionic fingers, and optical fibers. The bionic fingers are made of shape memory polymer doped with permanent magnet particles. Each bionic finger in the memory gripper is solidified in an upright state, and is shaped into a preset retracted shape under conditions above the glass transition temperature and then magnetized, thereby realizing dual-state conversion. The present invention solves the problems of insufficient flexibility and greater difficulty in operation that are common in existing SMP-based gripping robots.

Description

Technical Field

[0001] The present invention belongs to the field of flexible micro-robots, and in particular relates to an intelligent micro-gripper, a micro-memory gripper controlled by optical and magnetic means, and a method for preparing the memory gripper. Background Art

[0002] Gripping robots based on shape memory polymers (SMPs) are a cutting-edge class of flexible microrobots. These robots leverage the memory recovery properties of SMPs to adapt their shape in response to external stimuli (such as heat, electricity, magnetism, and light), enabling controlled motion. Because these robots eliminate the need for fly-by-wire control, they are extremely miniaturized and hold broad application prospects in aerospace, biomedicine, 4D printing, flexible microelectronics, and other fields.

[0003] Traditional drive technologies for SMP robots mainly include electrothermal, photothermal, and magnetic drive. Electrothermal drive achieves dynamic control by forming heating electrodes within a shape memory polymer matrix and then heating the material under power. Photothermal drive typically utilizes electromagnetic waves, such as infrared, to irradiate the shape memory polymer. The shape memory polymer absorbs the infrared radiation energy and converts it into heat, thereby regulating its own temperature and shape. Magnetic drive technology makes the robot components magnetically conductive, and then controls their movements through a dynamic magnetic field.

[0004] In actual applications, the above three driving technologies are usually unable to control the gripping robot over long distances. The control process may be limited by structure and space, and it is impossible to accurately and differentially control different structures in the gripping robot. The operation flexibility is poor and the practical value is limited. Summary of the Invention

[0005] In order to solve the common problems of insufficient flexibility and difficult operation of existing SMP-based gripping robots, the present invention provides an intelligent micro gripper, a micro memory gripper with combined optical and magnetic control, and a method for preparing the memory gripper.

[0006] The technical solution provided by the present invention is:

[0007] An intelligent micro-gripper comprises a memory gripper, an optical signal generator, a magnetic field generating device and a controller.

[0008] The memory gripper consists of a base, multiple bionic fingers fixedly attached to the base, and optical fibers embedded in the base or within each bionic finger. The bionic fingers are made of a shape-memory polymer doped with permanent magnet particles. Each bionic finger is solidified in an upright position, shaped into a pre-set, collapsed configuration above its glass transition temperature, and then magnetized. The bionic fingers retain their bending under specified temperature and magnetic field conditions and return to an upright position upon removal of the magnetic field. The optical fibers transmit the optical signals that control the temperature of the bionic fingers.

[0009] The optical signal generator includes a light source and a multi-channel optical switch. The light source is used to generate multiple optical signals and output them through multiple independent output ports. The optical switch is used to control the on / off of each output port. Each output port of the light source is connected to an optical fiber on the base of the memory gripper or the bionic finger.

[0010] The magnetic field generator is used to generate a directional magnetic field capable of driving the gripper to bend into a predetermined configuration. A controller is electrically connected to the optical signal generator and the magnetic field generator. The controller controls the optical signal generator to emit optical signals to a designated bionic finger to achieve targeted heating of the bionic claw, and controls the magnetic field generator to generate or remove a magnetic field in a designated area. This magnetic field then drives the bionic claw, which is above its glass transition temperature, to undergo a morphological change, thereby achieving a designated gripping or releasing action.

[0011] As a further improvement of the present invention, when the intelligent micro-gripper performs a clamping action, the control logic of the controller is as follows:

[0012] (1) Determine the expected shape of each bionic finger based on the preset gripping posture.

[0013] The bionic fingers have two shapes: upright and bent. In the initial state, each bionic finger remains upright.

[0014] (2) Sending instructions to the optical signal generator to emit optical signals to each bionic finger with the expected bent shape, so that it is transformed from the glass state to the rubber state.

[0015] (3) An opening command is issued to the magnetic field generating device to generate a directional magnetic field of a specified direction and intensity at the position of the memory clamp, so that each bionic finger in the rubber state bends.

[0016] (4) Sending a command to the optical signal generator to stop emitting the optical signal, so that the bent bionic finger returns from the rubber state to the glass state.

[0017] (5) Send a closing command to the magnetic field generating device so that the position of the memory clamp is restored to a non-magnetic field environment; at this time, the memory clamp is in a preset clamping posture.

[0018] As a further improvement of the present invention, when the intelligent micro-gripper performs a release action, the control logic of the controller is as follows:

[0019] (1) Determine the expected shape of each bionic finger based on the preset release posture.

[0020] (2) Sending instructions to the optical signal generator to emit optical signals to each bionic finger whose expected shape changes from bending to upright, so that it changes from glass state to rubber state and returns to upright state.

[0021] (3) Send a command to the light signal generator to stop emitting light signals, so that the bionic finger returns from the rubber state to the glass state; at this time, the memory gripper completes the release of the clamped object.

[0022] As a further improvement of the present invention, the controller pre-stores the heating curve and recovery curve of the bionic finger at different infrared powers. The controller queries the heating curve or recovery curve according to the current infrared power and heating time, and then identifies the current phase of the bionic finger.

[0023] As a further improvement, each bionic finger of the intelligent microgripper is equipped with a miniature temperature sensor, which is electrically connected to the controller via a signal cable. The controller uses the temperature sensor to detect the real-time temperature of each bionic finger and identify its current phase.

[0024] As a further improvement to the present invention, the intelligent microgripper also includes a multi-degree-of-freedom robotic arm with a memory gripper mounted at its end. The robotic arm is used to drive the memory gripper to move in space. The robotic arm is electrically connected to a controller that controls the motion trajectory of the robotic arm.

[0025] The present invention also includes a micro-memory gripper with combined optical and magnetic control, which includes a base, a plurality of bionic fingers fixedly connected to the surface of the base, and an optical fiber embedded in the base or each bionic finger. The bionic fingers are made of a shape memory polymer doped with permanent magnet particles. Each bionic finger is solidified in an upright state and shaped into a preset collapsed shape under conditions above the glass transition temperature before being magnetized. The bionic fingers have the characteristics of remaining bent under a specified temperature and magnetic field environment and returning to an upright position after the magnetic field is removed; the optical fiber is used to transmit an optical signal that can regulate the temperature of the bionic fingers.

[0026] As a further improvement of the present invention, the permanent magnet particles are neodymium iron boron powder, the shape memory polymer is prepared by mixing epoxy resin and curing agent in a mass ratio of 3:1, and the doping amount of the permanent magnet particles in the material for preparing the bionic finger is 30-65wt%.

[0027] As a further improvement of the present invention, the bionic fingers are distributed in a ring shape on the base, and each bionic finger has a diameter of 120 μm, a height of 1200 μm, and a spacing of 800 μm.

[0028] The present invention also includes a method for preparing a memory gripper, which is used to prepare the aforementioned optically and magnetically controlled micro memory gripper. The method comprises the following steps:

[0029] 1. Mold preparation

[0030] A mold with a groove on its surface is prepared using silicone material, and the groove matches the shape of the base in the memory clamp.

[0031] A femtosecond laser processing system is used to process multiple finger-shaped grooves in the groove of the mold, which match the shape and spatial distribution of each bionic finger in the memory gripper.

[0032] 2. Curing molding

[0033] The monomers of the shape memory polymer and the permanent magnet particles are mixed in a preset ratio and vacuum defoamed to obtain material one; the monomers of the shape memory polymer are mixed in a preset ratio and vacuum defoamed to obtain material two.

[0034] The material is injected into the mold to fill the finger grooves, and an optical fiber and / or a temperature sensor are pre-embedded in each finger groove; after scraping off the excess material, the first curing is carried out under the specified curing conditions.

[0035] The second material is injected into the mold to fill the groove, and then cured for the second time under the specified curing conditions; demoulding is completed after the second curing.

[0036] 3. Shaping and magnetization

[0037] The demoulded product is heated to a temperature higher than the glass transition temperature Tg of the material, and then each bionic finger is bent into a preset shape; and the product is magnetized by a strong magnetic field under forced conditions, thereby obtaining the required memory gripper.

[0038] The technical solution provided by the present invention has the following beneficial effects:

[0039] This invention uses a shape-memory polymer doped with permanent magnet particles to create a memory gripper. After reshaping the bionic finger, the gripper is magnetized. This allows the gripper to switch between gripping and releasing positions similar to those of a human hand, controlled by infrared light and a magnetic field. This solution overcomes the challenge of miniaturizing soft grippers.

[0040] Different from traditional belt-constrained clamps, the present invention uses optical fibers integrated into the memory clamp to achieve directional transmission of light signals emitted by the light source, thereby directionally heating the bionic fingers, so that different bionic fingers in the memory clamp can be deformed as needed, thereby achieving more precise manipulation and completing more complex clamping actions.

[0041] The present invention also provides a method for preparing a memory gripper based on a combination of femtosecond laser processing technology and magnetic nanoparticle-doped SMP template transfer technology, thereby reducing the manufacturing cost of the intelligent microgripper and laying the foundation for the market application of the solution.

[0042] Micromanipulators integrated onto optical fibers leverage the fiber's soft and slender properties to enable manipulation of micro-matter in challenging space and lightless environments. Furthermore, the fabricated memory gripper, leveraging the fine structure of biomimetic fingers, can be used to non-destructively grasp, transfer, and release fragile microarthropods (easily damaged by tweezers or adhesive grasping). The fabrication of micromanipulators and the research on their ability to manipulate micro-objects are of great significance to the advancement of fields such as biology, optics, and electromechanics. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the intelligent micro-gripper provided in Example 1 of the present invention.

[0044] Figure 2 This is a schematic structural diagram of the memory clamp provided in Example 1 of the present invention.

[0045] Figure 3 This is a comparison diagram of the principle and actual object of the memory gripper in Example 1 of the present invention achieving shape transformation under the combined drive of optical and magnetic signals.

[0046] Figure 4 In Example 1 of the present invention, a schematic diagram of an intelligent micro-gripper including a robotic arm is provided.

[0047] Figure 5 This is a schematic diagram of the principle of implementing different clamping actions by the memory clamp in Example 2 of the present invention.

[0048] Figure 6 This is a manufacturing flow chart of the memory clamp in Example 2 of the present invention.

[0049] Figure 7 This is a graph showing the relationship between the doping concentration of NdFeB particles and the bending angle of the micropillars in the test experiment.

[0050] Figure 8 This is a graph showing the relationship between the aspect ratio of the micropillar and the bending angle of the micropillar in the test experiment.

[0051] Figure 9This is a diagram showing the relationship between the magnetic induction intensity of the driving magnetic field and the bending angle of the micropillar in the test experiment.

[0052] Figure 10 This is the stability curve of the memory gripper under multiple rounds of cyclic bending recovery in the test experiment.

[0053] Figure 11 A comparison diagram of the principle and actual object of the memory gripper to grasp and transfer the target object in the test experiment

[0054] Figure 12 This is a graph showing the temperature change of the memory clamp under laser signal at different doping concentrations in the test experiment.

[0055] Figure 13 This is a comparison chart of the heating effect of the memory gripper under different laser power conditions in the test experiment.

[0056] Figure 14 A comparison chart of the heating effect of the memory gripper under different micro-pillar spacing conditions in the test experiment.

[0057] Figure 15 A diagram showing an example of a memory gripper being used to grasp and transfer a spherical target in a test experiment.

[0058] Figure 16 A case diagram of the memory gripper being used to grasp and transfer a target object under light-shielded conditions in a test experiment.

[0059] Figure 17 A diagram showing an example of a memory gripper being used to grasp and transfer an object inside a pipe during a test experiment.

[0060] Figure 18 A diagram showing an example of a memory gripper being used to grasp and transfer a living object in a test experiment. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0062] Example 1

[0063] This embodiment provides an intelligent micro-gripper, such as Figure 1As shown, it includes: a memory gripper, an optical signal generator, a magnetic field generating device, and a controller. Among them, the memory gripper is a micro-bionic gripper that can freely transform its own shape under the joint drive of optical and magnetic signals. The optical signal generator, the magnetic field generating device, and the controller together constitute the relevant components that can generate specified optical and magnetic signals as needed, thereby controlling the shape of the memory gripper. The memory gripper in the intelligent micro-gripper of this embodiment can be designed as a micron-level structure, thereby realizing flexible grasping and releasing of various micron-level targets.

[0064] like Figure 2 As shown, the memory gripper in this embodiment includes a base, a plurality of bionic fingers and optical fibers. The bionic fingers are fixedly connected to the surface of the base, and one end of each optical fiber in the optical fiber bundle is respectively embedded in the base or each bionic finger in the memory gripper. In this embodiment, the optical fiber bundle is used to transmit an optical signal that can adjust the temperature of the bionic finger. The bionic finger provided in this embodiment is made of a shape memory polymer doped with permanent magnet particles. Each bionic finger in the memory gripper in this embodiment is solidified in an upright state and is magnetized after being shaped into a preset retracted shape under conditions above the glass transition temperature.

[0065] The bionic fingers in the memory gripper of this embodiment are made of shape memory polymer and permanent magnet particles, so each bionic finger has both thermal response and magnetic response characteristics. The thermal response characteristic refers to the fact that the main material of the bionic fingers provided in this embodiment is shape memory polymer, and thus has the ability to automatically restore its original shape when the temperature is higher than the glass transition temperature TG. Specifically, the bionic fingers in the memory gripper of this embodiment are in a rubbery state when the temperature is higher than the glass transition temperature TG of the shape memory polymer. In this state, the entire bionic finger structure is soft and can be restored to its original shape after solidification, as well as deformed under the action of external force. When the temperature is lower than the glass transition temperature TG of the shape memory polymer, the bionic finger is in a glassy state and can stably maintain its shape before "cooling". The texture of the cooled bionic finger is hard and difficult to deform under the action of external force.

[0066] The magnetic response characteristic refers to the fact that the bionic finger of this embodiment is magnetized after being shaped into a preset collapsed shape. Therefore, in the rubber state, if the memory clamp is placed in a directional magnetic field of a specified direction and intensity, the bionic finger will remain in the collapsed shape before magnetization under the action of the magnetic force on the large number of magnetized permanent magnet particles inside. When the memory clamp is in a non-magnetic field environment, the individual permanent magnet particles will not be subjected to similar magnetic forces. At this time, the bionic finger will only exhibit thermal response characteristics. It should be supplemented that: in the glass state, the bionic finger in the memory clamp of this embodiment is hard in texture, so even if it is placed in a directional magnetic field, the bionic finger will not bend to the collapsed shape before magnetization.

[0067] In summary, the bionic finger in the memory gripper provided in this embodiment has the characteristics of remaining bent at a specified temperature (above the glass transition temperature of the material) and in a magnetic field environment (same direction as the strong magnetic field used during magnetization), and returning to an upright position after the magnetic field is removed. Specifically, the morphological changes of the bionic finger in this embodiment under different temperature and magnetic field conditions are shown in the following table:

[0068] Table 1: The morphology of the bionic finger at different temperatures and magnetic fields

[0069]

[0070] Combined with Table 1, it can be seen that by adjusting the temperature of the memory gripper and the magnetic field environment in which it is located, the shape of each bionic finger can be adjusted, thereby achieving actions similar to grasping (i.e., each bionic finger is retracted) and releasing (i.e., each bionic finger remains upright) of the mechanical gripper.

[0071] In this embodiment, the configuration of the memory gripper and bionic fingers is not limited. In a typical embodiment, a pincer-shaped memory gripper with two bionic fingers can be designed, or a four-finger gripper with four symmetrically arranged bionic fingers can be used. Even a five-finger gripper designed to mimic the human hand is possible.

[0072] Existing photothermal-driven SMP gripping robots generally choose to irradiate the memory gripper with a light source, thereby changing the temperature of the memory gripper to achieve the purpose of regulating the shape of the memory gripper. However, this direct irradiation method has two disadvantages: First, the direct irradiation method cannot only synchronously heat up all the bionic fingers in the memory gripper, and perform directional control on different bionic fingers. And the irradiation process is easily blocked by other structures in the actual application scenario. Second, in the process of miniaturizing the memory gripper, it is difficult to miniaturize the light source while ensuring the power. Therefore, in some specific cavities and narrow internal spaces of structures, the light source is placed synchronously with the memory gripper, making it difficult to achieve radiation and temperature control of the memory gripper.

[0073] In this embodiment, optical fibers are implanted within the bionic fingers of the memory gripper and electrically connected to a signal generator, thereby overcoming the aforementioned two major problems. Specifically, the optical signal generator employed in this embodiment includes a light source and a multi-channel optical switch. The light source is used to generate multi-channel optical signals and output them through multiple independent output ports. The optical switch is used to control the on / off state of each output port. The output ports of the light source correspond one-to-one with the bionic fingers in the memory gripper, and each output port is connected to an optical fiber on one of the bionic fingers in the memory gripper.

[0074] Using the optical signal generator of this embodiment, when heating a bionic finger in a memory gripper to achieve motion control, the light source is first turned on, and then the optical switch for the corresponding channel is turned on. The light signal emitted by the light source is then transmitted directly via optical fiber to the designated bionic finger, where it penetrates and is fully absorbed. The molecules and atoms within the bionic finger material then "resonate" with the light signal, generating strong vibrations and rotations, which in turn raise the material's temperature, achieving the desired heating effect.

[0075] As can be seen, this embodiment uses optical fiber to transmit light signals in a directional manner, thereby separating the light source from the memory gripper. In practical applications, the optical fiber of this embodiment can be bent and can accompany the memory gripper into deep holes or narrow, enclosed spaces with poor lighting conditions. This overcomes the limitations of existing photothermal SMP robots that prevent them from being applied in specific scenarios.

[0076] In addition, it should be noted that the above content of this embodiment introduces a solution for directional heating of the bionic fingers by directly transmitting the light signal output by the light source to each bionic finger through multiple optical fibers. In other embodiments, it is assumed that the structural size of the bionic finger is extremely small, and it is difficult to implant optical fibers on the end face of each bionic finger for directional transmission of the light signal. Alternatively, only one optical fiber can be used, and the end of the optical fiber can be implanted into the base of the memory gripper (the scale of the base is significantly larger than the bionic finger connected thereto). The light signal transmitted by the optical fiber heats all the bionic fingers connected to the base at the same time, so as to achieve morphological control of all bionic fingers. Of the above two optical fiber installation methods, although the latter is not as precise as the former in terms of control, it can also achieve morphological control of the bionic fingers to a certain extent.

[0077] Existing magnetically driven SMP gripping robots typically modify biomimetic fingers with ferromagnetic materials. These fingers are then subjected to a differentially distributed special magnetic field, which exerts an attractive or repulsive force on the ferromagnetic fingers to control their deformation in a specific direction. While effective, this manipulation method requires high control over parameters such as the direction, intensity, and spatial distribution of the magnetic field. This makes practical implementation difficult and expensive.

[0078] In this embodiment, a completely new strategy is adopted to achieve magnetic control of the shape of the memory gripper. Specifically, in this embodiment, the bionic fingers of the memory gripper are mixed with unmagnetized permanent magnet material. In the post-processing of the memory gripper, each bionic finger in the memory gripper is first solidified in an upright state. The solidified shape is the initial shape of the memory gripper; in the absence of external force and magnetic field, the memory gripper can always automatically return to this shape when heated to above the glass transition temperature. The memory gripper is then heated, and under conditions above the glass transition temperature, the softened bionic fingers are reshaped into a preset retracted shape and then magnetized.

[0079] Before magnetization, the reshaped shape of the memory gripper can be referred to as the second shape of the memory gripper. After magnetization, the magnetic moment arrangement of the permanent magnet particles doped in the bionic fingers changes from disorder to order. At this point, even after the external force used to constrain the bionic fingers is removed, the magnetic force exerted on each bionic finger in the magnetic field alone can continue to constrain the bionic fingers in this state. In subsequent applications, simply providing an additional magnetic field with the same direction and similar intensity as the strong magnetic field used when magnetizing the memory gripper can magnetically plasticize the softened bionic fingers above the glass transition temperature, causing them to transform from their initial shape to their second shape. Conversely, if the magnetic field constraining the shape of the memory gripper is removed at this point, the memory gripper will autonomously recover from its second shape to its initial shape under the influence of the memory recovery properties of the SMP material used in the bionic gripper.

[0080] Therefore, based on the above-mentioned magnetic properties of the memory clamp provided in this embodiment, in order to achieve the shape control of the memory clamp, the intelligent micro clamp provided in this embodiment also includes a magnetic field generating device. The magnetic field generating device is used to generate a directional magnetic field that can drive the clamp to bend to a preset shape. In practical applications, the magnetic field generating device can use an electromagnet, and then control the generation and cancellation of the additional magnetic field by adjusting the on and off of the driving current in the electromagnet. In other embodiments, the magnetic field generating device can also directly use a permanent magnet, and drive the permanent magnet through a linear actuator to move it closer to or away from the memory clamp at a specified angle, so that a corresponding magnetic field is generated around the memory clamp or the magnetic field is "cancelled".

[0081] In the intelligent micro-gripper provided in this embodiment, a controller is used to jointly control the optical signal generator and the magnetic field generating device for adjusting the temperature and magnetic field of the memory clamp, so that the memory clamp can directly switch between the initial form and the second form to achieve the specified action of clamping the target object and releasing the target object. Specifically, the controller in this embodiment is electrically connected to the optical signal generator and the magnetic field generating device. The controller is used to control the optical signal generator to emit an optical signal to the specified bionic finger to achieve directional heating of the bionic claw, and to control the magnetic field generating device to generate or cancel the magnetic field in the specified area, and then use the magnetic field to drive the bionic claw above the glass transition temperature to change its shape to achieve the specified clamping or release action.

[0082] In actual application, Figure 3 As shown in the figure, when the intelligent micro gripper performs the gripping action, the control logic of the controller is as follows:

[0083] (1) Determine the expected shape of each bionic finger based on the preset gripping posture.

[0084] The bionic fingers have two shapes: upright and bent. In the initial state, each bionic finger remains upright.

[0085] (2) Sending instructions to the optical signal generator to emit optical signals to each bionic finger with the expected curved shape, heating it so that it is transformed from a glass state to a rubber state.

[0086] (3) An opening command is issued to the magnetic field generating device to generate a directional magnetic field of a specified direction and intensity at the position of the memory clamp, so that each bionic finger in the rubber state bends.

[0087] (4) Sending a command to the optical signal generator to stop emitting the optical signal, so that the bent bionic finger can cool naturally and return to the glass state from the rubber state.

[0088] (5) Send a closing command to the magnetic field generating device so that the position of the memory clamp is restored to a non-magnetic field environment; at this time, the memory clamp is in a preset clamping posture.

[0089] Accordingly, if Figure 3 As shown in the figure, when the intelligent micro gripper performs the release action, the control logic of the controller is as follows:

[0090] (1) Determine the expected shape of each bionic finger based on the preset release posture.

[0091] (2) Sending instructions to the optical signal generator to emit optical signals to each bionic finger whose expected shape changes from bending to upright, heating the bionic finger so that it changes from glass state to rubber state and returns to upright state.

[0092] (3) Send a command to the optical signal generator to stop emitting the optical signal, so that the bionic finger cools naturally and returns to the glass state from the rubber state; at this time, the memory gripper completes the release of the clamped object.

[0093] In practical applications, repeated execution of the above-mentioned joint control strategies of multiple magnetic fields and temperatures can achieve continuous clamping and release of multiple targets to meet actual application needs.

[0094] In the solution of this embodiment, by transmitting light signals to the bionic fingers or base in the memory gripper through optical fibers, it is possible to heat them and drive the bionic fingers to undergo morphological transformation between the rubber state and the glass state. In this process, the longer the light signals in each bionic finger are turned on, the more heat each bionic gripper absorbs and converts, and the higher its own temperature will be. Therefore, how to control the duration of the transmitted light signal to achieve more precise temperature control, and then achieve a balance between the regulation effect and the energy consumption and life of the equipment, becomes a technical parameter that needs to be further optimized in this embodiment. To address this issue, this embodiment provides two different ideas to control the emission duration of the light signal.

[0095] Specifically, in the first solution, this embodiment pre-stores the heating curve and recovery curve of the bionic finger under different infrared powers in the controller. The controller queries the heating curve or recovery curve according to the current infrared power and heating time to determine the current temperature of the bionic finger, and then identifies the current phase of the bionic finger. During the heating process, when it is known from the heating curve that the bionic finger exceeds the preset glass transition temperature when heated and is converted from the glass state to the rubber state, the heating process can be terminated in time or the emission power of the light source can be reduced. During the clamping and releasing process of the target object, when it is known from the recovery curve that the bionic finger is lower than the preset glass transition temperature when cooled and is converted from the rubber state to the glass state, it means that the memory claw has hardened, thereby achieving a firm clamping of the target object, or ending the release action of the target object.

[0096] In the second solution, each bionic finger of the intelligent microgripper of this embodiment is also equipped with a miniature temperature sensor, which is electrically connected to the controller via a signal cable. The controller detects the real-time temperature of each bionic finger through the temperature sensor and then identifies the current phase of the bionic finger. The essence of solution one is to estimate the temperature of the bionic finger in combination with the heating power working curve, and then make judgments and decisions. In solution two, the temperature of the bionic finger is directly measured by the sensor and the corresponding decision is made. In other solutions, thermal imaging equipment can also be used to perform non-contact temperature detection on the memory gripper or bionic finger.

[0097] The above two methods of obtaining the temperature of the bionic finger can be applied to different scenarios. For example, when the scale of the memory gripper and the bionic finger is relatively large and obviously exceeds the probe of the micro temperature sensor, the second solution can be used. On the contrary, when the scale of the memory gripper and the bionic finger is too small and the implantation of the temperature sensor is not allowed, the first solution can be selected. In the first solution, in order to provide the estimation accuracy of the bionic claw temperature, the heating curve and recovery curve of the bionic finger under different ambient temperatures and heating power conditions can be further obtained through pre-testing. Then, in actual application, the ambient temperature is first obtained, and then the corresponding heating curve or cooling curve is selected in combination with the ambient temperature, and then the temperature is estimated.

[0098] In the actual product of the intelligent micro gripper provided in this embodiment, Figure 4 As shown, the system also includes a multi-degree-of-freedom robotic arm with a memory gripper mounted at the end thereof. The robotic arm is used to drive the memory gripper to move in space. The robotic arm is electrically connected to a controller that controls the motion trajectory of the robotic arm.

[0099] Example 2

[0100] On the basis of the solution in Example 1, this embodiment further provides a micro memory gripper that is jointly controlled by light and magnetism, which is the memory gripper used in the intelligent micro gripper in Example 1.

[0101] The micro-memory gripper, which is controlled by both light and magnetism, comprises a base, multiple bionic fingers fixedly connected to the surface of the base, and optical fibers embedded in the base or each bionic finger. The bionic fingers are made of a shape-memory polymer doped with permanent magnet particles. Each bionic finger is solidified in an upright position and shaped into a preset collapsed shape above the glass transition temperature before being magnetized. The bionic fingers have the ability to remain bent under specified temperature and magnetic field conditions and return to an upright position after the magnetic field is removed. The optical fibers are used to transmit optical signals that can regulate the temperature of the bionic fingers.

[0102] In the product solution of this embodiment, the permanent magnet particles are made of neodymium iron boron powder; the shape memory polymer is composed of epoxy resin and curing agent in a mass ratio of 3:1. In the raw materials used to prepare the bionic finger, the doping level of the permanent magnet particles in the shape memory polymer has an impact on the performance of the memory gripper. If the doping level of the permanent magnet particles is too low, the bionic finger exhibits weak magnetic properties and may not be able to transition from its initial form to its second form or maintain its stability in a magnetic field after magnetization. If the doping level of the permanent magnet particles is too high, the shape memory recovery properties of the bionic finger may be impaired, preventing it from autonomously recovering its shape above the glass transition temperature. It may also reduce the toughness of the bionic finger, making it more susceptible to fracture or damage during a limited number of shape transitions. In this embodiment, the optimal doping ratio was determined to be 30-65 wt% of the permanent magnet particles in the material.

[0103] In a memory gripper, the morphology and spatial distribution of the bionic fingers also affect the final gripping performance and deformation characteristics of the product. In the more optimized solution determined in this embodiment, the bionic fingers should be distributed in a ring on the base, and the four-finger gripper is more versatile, capable of performing tasks such as gripping and transferring most targets. In this type of memory gripper, the typical structural proportions are: the diameter of each bionic finger is 120μm; the height is 1200μm; and the spacing is 800μm.

[0104] The memory gripper provided in this embodiment can install optical fibers at each bionic finger, thereby achieving local heating and morphological control of different bionic fingers. Figure 5 As shown, the different bionic fingers in the memory gripper can be shaped differently according to different application scenarios, thereby achieving more refined manipulation effects. Taking a six-fingered gripper as an example, if only two fingers on opposite sides are bent, a "pinch" action can be performed. When all four fingers are bent simultaneously, a "grip" action can be achieved.

[0105] The solution provided in this embodiment further provides another method for preparing a memory clamp, which is used to prepare the aforementioned optical and magnetic combined control micro memory clamp, such as Figure 6 As shown, the preparation method comprises the following steps:

[0106] 1. Mold preparation

[0107] A mold with a groove on its surface is prepared using silicone material, and the groove matches the shape of the base in the memory clamp.

[0108] A femtosecond laser processing system is used to process multiple finger-shaped grooves in the groove of the mold, which match the shape and spatial distribution of each bionic finger in the memory gripper.

[0109] 2. Curing molding

[0110] The monomers of the shape memory polymer and the permanent magnet particles are mixed in a preset ratio and vacuum defoamed to obtain material one; the monomers of the shape memory polymer are mixed in a preset ratio and vacuum defoamed to obtain material two.

[0111] The material is injected into the mold to fill the finger grooves, and an optical fiber and / or a temperature sensor are pre-embedded in each finger groove; after scraping off the excess material, the first curing is carried out under the specified curing conditions.

[0112] The second material is injected into the mold to fill the groove, and then cured for the second time under the specified curing conditions; demoulding is completed after the second curing.

[0113] 3. Shaping and magnetization

[0114] The demoulded product is heated to a temperature higher than the glass transition temperature Tg of the material, and then each bionic finger is bent into a preset shape; and the product is magnetized by a strong magnetic field under forced conditions, thereby obtaining the required memory gripper.

[0115] Test Experiment

[0116] In order to verify the performance of the micro gripper and memory gripper provided by the present invention, Figure 6 As shown, technicians manufactured corresponding samples and carried out relevant test experiments. The experimental content and data are shown below:

[0117] 1. Sample manufacturing

[0118] 1.1, Template manufacturing:

[0119] A femtosecond laser machining system path diagram was drawn based on the spatial distribution of the biomimetic fingers in the pre-set memory gripper. The silicone material was affixed to a glass slide with double-sided tape, and the path diagram was imported into the femtosecond laser machining system. The designed pattern was machined onto the silicone substrate using processing parameters of 80mW average power and a scanning speed of 2mm / s. The number of laser scan repetitions was adjusted to create a high-aspect-ratio micropore array on the silicone material, ultimately yielding the desired silicone template. The femtosecond laser repeatedly scanned the silicone surface in a circular scanning path to increase the depth of the micropores machined.

[0120] 1.2. Memory gripper manufacturing:

[0121] Pure SMP is prepared according to the ratio of epoxy resin to curing agent in a ratio of 3:1, and then NdFeB powder is added to the pure SMP to obtain a mixture material endowed with photothermal response and magnetic response properties. The silicone material used is purchased AB glue in a ratio of 1:1 with a thickness of 2mm. The shape memory polymer used is epoxy resin and curing agent in a ratio of 3:1, and the NdFeB powder used has a diameter of 5μm. The evenly stirred mixture is applied to the surface of the silicone template and vacuumed for 15 minutes to ensure that the mixture completely enters the interior of the silicone template structure. The excess mixture on the surface is then scraped off and pure SMP is applied again. Finally, after curing and demolding, a four-claw memory clamp structure is obtained.

[0122] Among them, the base uses pure SMP, which is conducive to the transmission of light due to its high transparency; on the other hand, since the infrared absorption rate of pure SMP is relatively low, its surface temperature will be lower than that of the bionic finger part doped with NdFeB.

[0123] 1.3. Shaping and magnetization:

[0124] Under near-infrared light irradiation, the bionic fingers (micropillars) in the memory gripper become soft, and external force is applied to cause the micropillars to bend inward into a claw shape at the same time. When the near-infrared light is removed, the memory gripper is fixed into a temporary shape and magnetized in a 1.2T uniform magnetic field to obtain a memory gripper with both light and magnetic responses.

[0125] This step uses magnetization to cause the four micropillars to simultaneously respond inwards to magnetic field stimulation, forming a microclaw configuration that is conducive to capturing targets. Before magnetization, the full orientation of the four micropillars is uncertain under the influence of the magnetic field, making manipulation impossible. However, after shaping and magnetization, each micropillar can maintain its designated configuration in the magnetic field, enabling the memory gripper to switch between two states.

[0126] 1.4. Fiber optic integration:

[0127] In this experiment, the end of an infrared fiber laser was bonded to the base of a memory gripper using adhesive. The fiber laser generates an optical signal that drives the memory gripper to heat up. Utilizing the excellent optical transmission properties of optical fiber, which can be extended and bent, the memory gripper can be optically actuated in confined spaces, achieving improved control and precision. In this experiment, the fiber laser used was the Changchun New Industries MDL-III-808 model.

[0128] 2. Analysis of factors affecting bending performance:

[0129] During the fabrication of memory gripper samples, this experiment produced samples with varying NdFeB concentrations and micropillar aspect ratios. An experimental plan was then developed to test the micropillar curvature of these memory grippers using a controlled variable method under varying driving magnetic field intensities. This approach further explored the key factors influencing the tuning of micropillar morphology in the memory gripper. During the experiment, the curvature of the micropillars with different parameters was measured using a CA100C contact angle measurement system from Innuo, a Chinese company.

[0130] According to the experimental data, the relationship between the doping concentration of NdFeB particles and the bending angle of the microcolumns is as follows: Figure 7 Shown; analysis Figure 7 The data shows that the higher the doping concentration of NdFeB, the greater the bending angle of the microcolumn.

[0131] According to the experimental data, the relationship between the height-to-diameter ratio of the microcolumns and the bending angle of the microcolumns is as follows: Figure 8 Shown; analysis Figure 8 The data shows that the larger the aspect ratio of the microcolumn is, the larger the bending angle of the microcolumn is.

[0132] In order to study the relationship between the magnetic induction intensity of the driving magnetic field and the bending angle of the micro-pillar, this experiment chose to adjust the distance between the permanent magnet and the memory clamp, and then measure the change in the magnetic field intensity at the memory clamp under different permanent magnet distance conditions. Then, the change in the bending angle of the micro-pillar under different permanent magnet distance conditions (corresponding to different magnetic field intensities) was analyzed. The experimental data obtained are as follows Figure 9 Analysis Figure 9 The data shows that the closer the permanent magnet is to the memory clamp, the higher the magnetic field strength at the memory clamp. The greater the magnetic field strength, the larger the full angle of the micropillar.

[0133] In addition, this experiment can also compare and analyze the changes in the full angle of the corresponding magnetic field of micropillars with different lengths, and the results are also reflected in Figure 9 From the data in the figure, it can be found that the higher the height of the microcolumn, the greater the bending angle under the same magnetic field.

[0134] 3. Stability Test

[0135] This experiment repeatedly tested the bending and recovery processes of memory grippers with different NdFeB concentrations under magnetic field drive to verify the stability of the product. During the repetitive experiments, technicians found that when the NdFeB doping concentration reached 70%, the microcolumns became too rigid. This caused the memory grippers to break easily during repeated use, affecting the stability of the product. Therefore, subsequent experiments should select products with a NdFeB powder doping content of 50%.

[0136] Furthermore, when the doping content was 50%, the experiment also conducted stability tests under different conditions, resetting and removing the magnetic field, recording the changes in the bending angle of the micropillars, and obtaining the following Figure 10 Repeated experimental data are shown. Figure 10 The data show that even after 10 repeated bending and recovery, the micro-pillars in the memory gripper can still maintain a basically consistent curvature, indicating that the memory gripper designed in the present invention has good stability.

[0137] 4. Analysis of factors affecting temperature control

[0138] Temperature is crucial for achieving morphological control and state retention in the memory gripper. This experiment further tested and analyzed factors influencing the temperature control of the micropillars in the memory gripper. During the experiment, the surface temperature of the memory gripper was measured using a Fotric 625C-L21 (Shanghai Thermal Imaging Technology Co., Ltd.).

[0139] 4.1 Verification of Morphological Control Performance

[0140] This experiment first tested the memory gripper's ability to manipulate a tiny ball in the air under the synergistic effect of optical fiber transmission and magnetic field. The basic principles and actual results of the experimental process are as follows: Figure 11 As shown. Figure 11 Said you can see:

[0141] When the memory gripper is not affected by the external magnetic field and the optical fiber light guide, the micro-pillar array is in an upright state and the entire memory gripper is in its initial state. When light is conducted in the optical fiber, the photothermal effect causes the micro-pillar array to rapidly heat up to the glass transition temperature. Under the synergistic effect of the external magnetic field, the micro-pillar array bends inward, achieving precise capture of the tiny balls. Next, when the light source and the external magnetic field in the optical fiber are removed at the same time, the micro-pillar array still remains bent inward, and the memory gripper maintains its clamping state on the small balls. When light is output from the optical fiber again, the micro-pillar array reaches the glass transition temperature again due to the thermal effect, and then recovers its shape and becomes upright, achieving the rapid release of the tiny balls.

[0142] 4.2 Effect of Warm NdFeB Doping Concentration

[0143] This experiment first studied the temperature change of the memory gripper under the laser signal under the conditions of NdFeB doping concentration of 0%, 10%, 30%, and 50%. The experimental data obtained are as follows Figure 12 The left side of the figure shows the infrared image of the experimental process, and the right side shows the heating and cooling curves drawn according to the temperature test results.

[0144] analyze Figure 12The data shows that the higher the NdFeB doping concentration, the faster the memory gripper's heating and cooling rates. This is because NdFeB doping affects the material's absorption rate of light signals. To improve the memory gripper's sensitivity to light signals during control, the NdFeB doping concentration should be appropriately increased. However, excessive NdFeB doping concentrations should be avoided, as excessive concentrations can negatively impact the material's flexibility.

[0145] 4.3 Effect of laser power

[0146] This experiment further studies the relationship between the temperature of the memory clamp at different laser powers. The experimental data obtained are as follows: Figure 13 As shown in the figure, there is a positive correlation between laser power and the temperature increase of the memory clamp, indicating that higher laser power should be used to improve the temperature response rate of the memory clamp. However, in practical applications, the laser light source should not be too high, as high-power lasers may cause the local temperature of the memory clamp to be too high, which may cause the fiber cladding at the interface to burn.

[0147] 4.4 Effect of Micropillar Spacing

[0148] This experiment further tests the heating effect of the memory gripper under different micro-pillar spacings, and the experimental data obtained are as follows: Figure 14 As shown in the figure, the micropillar spacing is negatively correlated with the memory gripper's heating effect. This may be because a larger micropillar spacing results in a larger heat-absorbing structure and a larger heat dissipation surface between the structures. Based on this data, technicians can optimally adjust the memory gripper's structural dimensions and the number of optical fibers used.

[0149] 5. Testing of multiple application scenarios:

[0150] This experiment further tests the clamping effect of the memory clamp provided by the present invention on different types of objects. Figure 15 The experiment shows the memory gripper being used to grip a glass ball of the order of 100 micrometers (the ball has a diameter of 500 μm in the figure). This experiment verifies that the memory gripper of the present invention has a stable gripping ability for smooth spherical objects that are difficult to grip.

[0151] Figure 16 This figure shows the process of using the memory gripper of the present invention to selectively identify and grasp a target object in a dark environment, then release it to a designated location. The figure shows that the laser output through the optical fiber of the present invention not only achieves temperature regulation but also provides a certain lighting effect, facilitating object grasping in a dark environment.

[0152] Figure 17This experiment demonstrates the memory gripper of the present invention grasping an object within a curved pipe. Thanks to the fiber-optic transmission strategy for laser signals employed in the present invention, the memory gripper of this embodiment can effectively penetrate deep within the pipe to grasp the object. This experiment demonstrates the memory gripper's ability to grasp objects in confined spaces.

[0153] Finally, this experiment also used the memory gripper to clamp and non-destructively transform Daphnia. The experimental process is as follows: Figure 18 As shown, the released Daphnia can still remain active, which shows that the memory gripper provided by the present invention can be used to clamp and transfer living targets.

[0154] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An intelligent micro gripper, characterized in that: It includes: A memory gripper comprising a base, a plurality of bionic fingers fixedly connected to the surface of the base, and optical fibers embedded in the base or each bionic finger; the bionic fingers are made of a shape memory polymer doped with permanent magnet particles; each bionic finger is solidified in an upright state, shaped into a preset collapsed configuration at a temperature above the glass transition temperature, and then magnetized; the bionic fingers have the characteristics of remaining bent under a specified temperature and magnetic field environment and returning to an upright position after the magnetic field is removed; An optical signal generator comprising a light source and a multi-channel optical switch; The light source is used to generate multiple optical signals and output them through multiple independent output ports; the optical switch is used to control the on / off of each output port; each output port of the light source is connected to the base of the memory gripper or the optical fiber on the bionic finger; A magnetic field generating device, which is used to generate a directional magnetic field capable of driving the clamping jaws to bend to a preset shape; a controller electrically connected to the optical signal generator and the magnetic field generating device; the controller is used to control the optical signal generator to emit an optical signal to a designated bionic finger to achieve directional heating of the bionic claw, and to control the magnetic field generating device to generate or cancel a magnetic field in a designated area, thereby using the magnetic field to drive the bionic claw above the glass transition temperature to undergo a morphological change to achieve a designated gripping or releasing action; When the intelligent micro gripper performs a gripping action, the control logic of the controller is as follows: (1) Determine the expected shape of each bionic finger according to the preset gripping posture; The bionic fingers have the following forms: upright and bent. In the initial state, each bionic finger remains upright. (2) issuing a command to the optical signal generator to emit an optical signal to each bionic finger with the expected bent shape, so that the finger is transformed from a glass state to a rubber state; (3) issuing an opening command to the magnetic field generating device to generate a directional magnetic field of a specified direction and intensity at the position of the memory gripper, so that each bionic finger in the rubber state bends; (4) issuing a command to the optical signal generator to stop emitting the optical signal, so that the bent bionic finger returns from the rubber state to the glass state; (5) issuing a closing command to the magnetic field generating device so that the position of the memory clamp is restored to a non-magnetic field environment; at this time, the memory clamp is in a preset clamping posture; When the intelligent micro gripper performs a release action, the control logic of the controller is as follows: (1) Determine the expected shape of each bionic finger according to the preset release posture; (2) issuing a command to the optical signal generator to emit an optical signal to each bionic finger whose expected shape changes from bending to upright, so that the finger changes from a glassy state to a rubbery state and then returns to an upright state; (3) Sending a command to the optical signal generator to stop emitting the optical signal, so that the bionic finger returns from the rubber state to the glass state; at this time, the memory gripper completes the release of the clamped object and returns to the initial state.

2. The intelligent micro gripper according to claim 1, characterized in that: The controller pre-stores the heating curve and recovery curve of the bionic finger at different infrared powers; The controller queries the temperature rise curve or the recovery curve according to the current infrared power and heating time, and further identifies the current phase state of the bionic finger.

3. The intelligent micro gripper according to claim 1, characterized in that: Each bionic finger is also provided with a miniature temperature sensor, which is electrically connected to the controller via a signal cable; The controller detects the real-time temperature of each bionic finger through a temperature sensor, and then identifies the current phase state of the bionic finger.

4. The intelligent micro gripper according to claim 1, wherein: It also includes a multi-degree-of-freedom mechanical arm, the memory gripper is installed at the end of the mechanical arm, and the mechanical arm is used to drive the memory gripper to move in space; The robotic arm is electrically connected to the controller, and the controller is used to control the motion trajectory of the robotic arm.

5. An optical-magnetic combined control micro memory gripper of an intelligent micro gripper according to any one of claims 1 to 4, characterized in that: The device comprises a base, multiple bionic fingers fixedly connected to the surface of the base, and optical fibers embedded in the base or each bionic finger. The bionic fingers are made of a shape-memory polymer doped with permanent magnet particles. Each bionic finger is solidified in an upright state and shaped into a preset collapsed shape at a temperature above the glass transition temperature before being magnetized. The bionic fingers have the characteristics of remaining bent under a specified temperature and magnetic field environment and returning to an upright position after the magnetic field is removed. The optical fiber is used to transmit an optical signal capable of regulating the temperature of the bionic finger.

6. The optical-magnetic combined control micro memory gripper according to claim 5, characterized in that: The permanent magnet particles are made of neodymium iron boron powder; the shape memory polymer is made of epoxy resin and curing agent in a mass ratio of 3:1; The doping amount of the permanent magnet particles in the material for preparing the bionic finger is 30-65 wt %.

7. The optical-magnetic combined control micro memory gripper according to claim 5, characterized in that: The bionic fingers are distributed in a ring shape on the base, and each bionic finger has a diameter of 120 μm, a height of 1200 μm, and a spacing of 800 μm.

8. A method for preparing a memory gripper, characterized in that: It is used to prepare the optical-magnetic combined control micro memory gripper as claimed in any one of claims 5 to 7, and the preparation method comprises the following steps:

1. Mold preparation A mold with a groove on its surface is prepared using silicone material, wherein the groove matches the shape of the base in the memory clamp; A femtosecond laser processing system is used to process multiple finger-shaped grooves in the groove of the mold, which match the shape and spatial distribution of each bionic finger in the memory gripper.

2. Curing molding The shape memory polymer monomer and the permanent magnet particles are mixed in a preset ratio and vacuum defoamed to obtain material 1; the shape memory polymer monomer is mixed in a preset ratio and vacuum defoamed to obtain material 2; Inject the material into the mold to fill the finger grooves, and embed optical fibers and / or temperature sensors in each finger groove; scrape off excess material and perform the first curing under specified curing conditions; Inject material 2 into the mold to fill the groove, and then perform a second curing under specified curing conditions; Demolding after the second curing is completed; 3. Shaping and magnetization The demoulded product is heated to a temperature higher than the glass transition temperature Tg of the material, and then each bionic finger is bent into a preset shape; and the product is magnetized by a strong magnetic field under forced conditions, thereby obtaining the required memory gripper.

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