A bistable magnetic actuator and its fabrication method

Abstract

This application belongs to the field of magnetic actuator technology, specifically disclosing a bistable magnetic actuator and its fabrication method. This application adds a magnetic soft layer to a bistable composite material layer. The magnetic soft layer includes uniformly laid magnetic particles, which are magnetized before curing. The magnetization direction is axial or circumferential along the surface of the bistable composite material layer, while the direction of the uniform magnetic field used for driving is inward or outward along the surface of the cylindrical shell. Therefore, there is a deviation between the uniform magnetic field and the magnetization direction of the magnetic particles. The uniform magnetic field can generate a magnetic torque to drive the magnetic soft layer, avoiding the problem of large magnetic field gradient attenuation and difficulty in driving when the separation distance is large under traditional gradient magnetic field force driving methods. The magnetic soft layer is prepared by injection molding, overall magnetization, and on-demand cutting. During preparation, it is directly allowed to solidify statically and then rapidly magnetized, avoiding the problems of strict requirements for the preparation environment and difficulty in controlling and changing the magnetization direction.

Description

Technical Field

[0001] This application belongs to the field of magnetic actuator technology, and more specifically, relates to a bistable magnetic actuator and its manufacturing method. Background Technology

[0002] Bistable composite material structures possess advantages such as light weight, excellent mechanical properties, and bistable configuration, making them promising for applications in high-tech fields such as aerospace, machinery, and electronics. However, they typically employ hydraulic, pneumatic, or direct loading methods for contact-based actuation and control, resulting in limited flexibility. In recent years, magnetically bistable composite material structures have emerged, demonstrating unique application potential and advantages due to their ability to achieve non-contact actuation under magnetic field influence.

[0003] Patent CN111416546A discloses a magnetic field-driven bistable structure and its fabrication method. This structure uses orthogonally laid composite laminates, with a magnetically sensitive deformation actuator bonded to both ends of the laminates. Under the influence of a magnetic field, the material structure can switch between two stable states. Patent CN114227741A discloses a magnetorheological elastomer-driven multistable manipulator. This manipulator includes two deformation units, with a magnetorheological elastomer actuator bonded to one end of each deformation unit. Under magnetic field drive, it can switch between three different stable states.

[0004] However, existing magnetically driven bistable structures have the following shortcomings: 1) When composite laminates are laid out orthogonally, the deformation is small, and the bending directions of the two stable states are opposite, making design difficult in application scenarios; 2) When composite laminates are laid out antisymmetrically, the deformation is large due to the material structure itself, requiring a larger driving force for deformation, which is difficult to achieve with a single magnetization direction bonded magnetorheological elastomer; 3) Existing driving methods mostly use gradient magnetic field force to generate deformation, which has problems such as severe magnetic field gradient attenuation, single deformation mode, and strict requirements for magnetic field direction. The fabrication of existing magnetically driven bistable structures has the following shortcomings: the magnetically sensitive deformation actuator or magnetorheological elastomer is made by mixing silicone rubber and magnetic particles uniformly and then curing them under a uniform magnetic field of 1.5T for 2 hours. The external magnetic field is applied for a long time during preparation, which requires strict preparation environment and makes it difficult to control and change the magnetization direction. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a bistable magnetic actuator and its manufacturing method, which aims to solve the problems of severe magnetic field gradient attenuation and strict magnetic field direction requirements when existing bistable composite material structures are deformed by relying on gradient magnetic field drive.

[0006] To achieve the above objectives, in a first aspect, this application provides a bistable magnetic actuator, comprising: a bistable composite material layer and a magnetic soft layer covering the upper surface and / or lower surface of the bistable composite material layer;

[0007] The bistable composite material layer is a laminated cylindrical shell structure;

[0008] The magnetic soft layer has a cuboid structure and adapts to a cylindrical shell shape as the bistable composite material layer cures.

[0009] The magnetic soft layer includes uniformly laid magnetic particles, which are magnetized before curing, with the magnetization direction being either axial or circumferential to the surface of the bistable composite material layer.

[0010] Preferably, the magnetic soft layer is multi-directionally magnetized so that it conforms to the stress deformation trend of the bistable composite material layer surface.

[0011] Preferably, the magnetic soft layer is divided into four regions along the diagonal, with the first and third regions being identical and arranged opposite each other, and the second and fourth regions being identical and arranged opposite each other.

[0012] Preferably, the magnetization directions of the first and third regions are along the axial direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell; the magnetization directions of the second and fourth regions are along the circumferential direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell, and the bistable magnetic actuator is in the first stable state.

[0013] Preferably, the magnetization directions of the second and fourth regions are along the axial direction of the surface of the bistable composite material layer and are inward relative to the center of the laminated cylindrical shell; the magnetization directions of the first and third regions are along the circumferential direction of the surface of the bistable composite material layer and are outward relative to the center of the laminated cylindrical shell, and the bistable magnetic actuator is in the second stable state.

[0014] Preferably, the thickness of the magnetic soft layer is 0.5mm-1mm.

[0015] Preferably, the unidirectional fiber-reinforced composite material in the bistable composite material layer is laid in an antisymmetric manner.

[0016] Preferably, the bistable magnetic actuator exhibits a cylindrical shell shape in both stable states, and the bending direction is the same in both stable states.

[0017] Preferably, the bistable magnetic actuator is applied to a flexible gripper or a multistable robot.

[0018] To achieve the above objectives, in a second aspect, this application provides a method for fabricating a bistable magnetic actuator, comprising:

[0019] S1. Mix the uncured soft substrate material liquid with magnetic particles and stir evenly to obtain a magnetic mixture fluid;

[0020] S2. Inject the magnetic mixture fluid into a cuboid mold, perform injection molding and solidification, and after static solidification, obtain an unmagnetized cuboid magnetic soft structure;

[0021] S3. The unmagnetized cuboid magnetic soft structure is placed in a uniform pulsed magnetic field for magnetization to obtain a cuboid magnetic soft structure with a specific magnetization direction.

[0022] S4. Cut the uncured composite single-layer board according to the preset laying angle, and then lay it up according to the preset laying method to obtain an uncured anti-symmetric composite laminate.

[0023] S5. Cut the cuboid magnetic soft structure with a specific magnetization direction obtained in S3 into a preset shape and magnetization direction, and use the same uncured soft substrate material liquid as in S1 as an adhesive to bond all the magnetic soft structures with preset shapes and magnetization directions to the upper and / or lower surfaces of the uncured antisymmetric composite material laminate obtained in S4 in a preset manner to obtain an uncured magnetic actuator.

[0024] S6. Place the uncured magnetic actuator in a cylindrical mold and heat it to cure, thereby obtaining a magnetic actuator with bistable characteristics.

[0025] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art:

[0026] (1) This application provides a bistable magnetic actuator by adding a magnetic soft layer on a bistable composite material layer. The magnetic soft layer includes uniformly laid magnetic particles. The magnetic particles are magnetized before curing. The magnetization direction is axial or circumferential along the surface of the bistable composite material layer. The direction of the uniform magnetic field used for driving is inward or outward along the surface of the cylindrical shell. Therefore, there is a deviation between the uniform magnetic field and the magnetization direction of the magnetic particles. The uniform magnetic field can generate a magnetic torque to drive the magnetic soft structure. Therefore, it can avoid the problem of difficulty in driving when the magnetic field gradient attenuation is large and the separation distance is far under the traditional gradient magnetic field force driving method.

[0027] (2) This application provides a method for manufacturing a bistable magnetic actuator, which prepares a magnetic soft layer by injection molding, overall magnetization, and cutting as needed. The preparation is directly statically solidified and then quickly magnetized, avoiding the problems of long duration of external magnetic field, strict requirements on the preparation environment, and difficulty in controlling and changing the magnetization direction in the existing preparation. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of a bistable magnetic actuator provided in an embodiment of this application.

[0029] Figure 2 These are schematic diagrams of two stable states of a bistable composite laminated cylindrical shell provided in the embodiments of this application, wherein (a) corresponds to the first stable state and (b) corresponds to the second stable state.

[0030] Figure 3 This is a schematic diagram of the torque direction required for the steady-state transition of a bistable composite laminated cylindrical shell provided in the embodiments of this application, wherein (a) corresponds to the transition from the first steady state to the second steady state, and (b) corresponds to the transition from the second steady state to the first steady state.

[0031] Figure 4 This is a schematic diagram of the magnetization direction of four triangular magnetic soft structures on the magnetic driver provided in the embodiment of this application, wherein (a) corresponds to the first steady state and (b) corresponds to complete flattening.

[0032] Figure 5 This is a schematic diagram of a method for manufacturing a bistable magnetic actuator provided in an embodiment of this application.

[0033] Figure 6 This is a schematic diagram showing the state of magnetic particles in the magnetic soft material provided in this application before and after magnetization.

[0034] Figure 7 This is a schematic diagram of the direction of the magnetic field required for the transition between two stable states provided in the embodiments of this application, wherein (a) corresponds to the transition from the first stable state to the second stable state, and (b) corresponds to the transition from the second stable state to the first stable state.

[0035] Figure 8 The gripper is composed of a magnetic actuator with bistable characteristics provided in the embodiments of this application, wherein (a) corresponds to the first stable state and (b) corresponds to the second stable state.

[0036] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0037] 1-Magnetic soft layer, 2-Bismolate composite material layer, 11-First region, 12-Second region, 13-Third region, 14-Fourth region, 21, 22, 23, 24-Single-layer plate. Detailed Implementation

[0038] For ease of understanding, the English abbreviations and related technical terms used in the embodiments of this application will be explained and described below.

[0039] A laminated cylindrical shell is a cylindrical shell structure composed of multiple layers of materials with different properties. This structure is usually made of composite materials, with each layer having a specific orientation and function to improve the overall strength and stiffness of the structure while reducing weight.

[0040] When the side of a cylinder is "cut" and unfolded into a plane, the resulting shape is a cylindrical shell.

[0041] The embodiments of this application are described below with reference to the accompanying drawings.

[0042] like Figure 1 As shown, this application provides a bistable magnetic actuator, comprising: a bistable composite material layer 2 and a magnetic soft layer 1 covering the upper and / or lower surfaces of the bistable composite material layer 2; the bistable composite material layer 2 is a laminated cylindrical shell structure; the magnetic soft layer 1 is a cuboid structure and adapts to the cylindrical shell shape as the bistable composite material layer cures; the magnetic soft layer 1 includes uniformly laid magnetic particles, which are magnetized before curing, with the magnetization direction being either the axial or circumferential direction of the bistable composite material layer surface. θ represents a preset layup angle, and α represents the angle between the fiber direction and the axial direction of the first stable cylindrical shell.

[0043] In this application, the bistable composite material layer 2 is embedded within the magnetic soft layer 1, providing bistable characteristics for the magnetic actuator. The magnetic soft layer 1 completely covers the surface of the bistable composite material layer 2 and deforms under the influence of magnetic torque in a uniform magnetic field. This application, while ensuring the bistable characteristics of the bistable composite material structure, utilizes the magnetic soft layer for contactless control, making it suitable for magnetic actuators requiring large deformation, rapid response, and the ability to autonomously maintain their deformed state.

[0044] Preferably, the magnetic soft layer is multi-directionally magnetized so that it conforms to the stress deformation trend of the bistable composite material layer surface.

[0045] It should be noted that, compared with the existing technology where single magnetization can only provide force in a single direction, this application further designs the magnetization direction of the magnetic soft layer. On the basis of the overall consistent magnetization direction of the magnetic actuator, different regions adopt different magnetization directions, resulting in deformation in different directions. This makes the magnetic torque distribution on the magnetic actuator more consistent with the driving force required to produce deformation, reducing the magnetic field required for the magnetic actuator to produce deformation, and reducing its driving difficulty and driving energy consumption.

[0046] Preferably, the magnetic soft layer 1 is divided into four regions along the diagonal, with the first region 11 and the third region 13 being the same and arranged opposite each other, and the second region 12 and the fourth region 14 being the same and arranged opposite each other.

[0047] Preferably, the magnetization directions of the first and third regions are along the axial direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell; the magnetization directions of the second and fourth regions are along the circumferential direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell, and the bistable magnetic actuator is in the first stable state.

[0048] Preferably, the magnetization directions of the second and fourth regions are along the axial direction of the surface of the bistable composite material layer and are inward relative to the center of the laminated cylindrical shell; the magnetization directions of the first and third regions are along the circumferential direction of the surface of the bistable composite material layer and are outward relative to the center of the laminated cylindrical shell, and the bistable magnetic actuator is in the second stable state.

[0049] Preferably, the thickness of the magnetic soft layer is 0.5mm-1mm.

[0050] Preferably, the unidirectional fiber-reinforced composite material in the bistable composite material layer is laid in an antisymmetric manner.

[0051] Preferably, the bistable magnetic actuator exhibits a cylindrical shell shape in both stable states, and the bending direction is the same in both stable states.

[0052] Preferably, the bistable magnetic actuator is applied to a flexible gripper or a multistable robot.

[0053] Example

[0054] In this embodiment, the bistable magnetic actuator has a magnetic soft layer covering the upper and lower surfaces of the bistable composite material layer. Based on different magnetization directions, it is divided into four triangular magnetic soft structures along the diagonal of the bottom face of the cuboid. The magnetization directions of the upper and lower magnetic soft structures are strictly the same, specifically including: 1) In the first stable state, the magnetization direction of the four magnetic soft structures on the upper and lower surfaces connected to the curved edge is along the axial direction of the cylindrical shell surface and outward relative to the center of the bistable composite laminate cylindrical shell; the magnetization direction of the four magnetic soft structures on the upper and lower surfaces connected to the straight edge should be along the circumferential direction of the cylindrical shell surface and inward relative to the center of the bistable composite laminate cylindrical shell; 2) In the second stable state, the magnetization direction of the four magnetic soft structures on the upper and lower surfaces connected to the curved edge is along the axial direction of the cylindrical shell surface and inward relative to the center of the bistable composite laminate cylindrical shell; the magnetization direction of the four magnetic soft structures on the upper and lower surfaces connected to the straight edge should be along the circumferential direction of the cylindrical shell surface and outward relative to the center of the bistable composite laminate cylindrical shell.

[0055] In this embodiment, the magnetic soft layer comprises a soft substrate material and magnetic particles in a 1:1 ratio. A higher magnetic particle content results in lower actuation difficulty. The soft substrate material is silicone rubber, and the magnetic particles are permanent magnet particles that have undergone initial magnetization before curing, specifically NdFeB powder with a particle size of 5-10 μm. A greater thickness of the magnetic soft layer achieves the same actuation effect with a lower magnetic particle mass fraction.

[0056] The magnetic soft layer may also cover only the upper or lower surface of the bistable composite material layer.

[0057] The four regions divided along the diagonal of the magnetic soft layer can also be triangular in shape.

[0058] The bistable composite material layer is a thin cuboid multilayer fiber-reinforced composite material structure cured into a cylindrical shell shape; the single-layer plate material is a unidirectional carbon fiber / epoxy resin fiber composite material, or it can be a composite material of glass fiber and other curing agents.

[0059] like Figure 1 As shown, the bistable composite laminated cylindrical shell is laid up in an antisymmetric manner: the layup angle is defined as the angle between the fiber direction of the unidirectional carbon fiber in the composite single-layer plate and the longitudinal direction, i.e., the y-axis, during layup. The antisymmetric layup consists of at least 4 single-layer plates (21, 22, 23 and 24), each single-layer plate having a thickness of 0.125 mm. Relative to the geometric mid-surface of the laminate, the single-layer plates are paired, with the same layup angle but opposite directions, and have the same material properties.

[0060] The bistable composite laminated cylindrical shell requires heat curing in a cylindrical mold after layup. After curing, it exhibits bistable characteristics due to the mechanical properties of carbon fibers resulting from the special layup method. Its two stable states are as follows: Figure 2 As shown. The two stable states, after curing, exhibit the following characteristics. Figure 2 The cylindrical shell shape shown in (a) represents the first steady state. After the load reaches the transformation condition, the straight edge of the first steady state becomes a curved edge, and the curved edge becomes a straight edge, and this state is maintained as described above. Figure 2 The new cylindrical shell shape shown in (b) remains unchanged, which is the second stable state. Both stable states exhibit a cylindrical shell shape and have the same direction of curvature.

[0061] When the bistable composite laminated cylindrical shell transitions from the first stable state to the second stable state, the required torque directions at each edge are as follows: Figure 3 As shown in (a): the two straight sides require outward torque relative to the cylindrical shell, and the two curved sides require inward torque relative to the cylindrical shell.

[0062] When the bistable composite laminated cylindrical shell transitions from the second stable state to the first stable state, the required torque directions at each edge are as follows: Figure 3 As shown in (b): the two straight sides require an outward torque relative to the cylindrical shell, and the two curved sides require an inward torque relative to the cylindrical shell.

[0063] The magnetization directions of this magnetic soft structure, when the bistable composite laminated cylindrical shell is in its first stable state or fully flattened, are as follows: Figure 4 As shown in (a) and (b), the y-axis is the axial direction of the first stable cylindrical shell, and the x-axis is perpendicular to the y-axis. When the bistable composite laminated cylindrical shell is in the first stable state, the magnetization direction of the four magnetic soft structures on the upper and lower surfaces connected to the curved edges is along the y-axis and outward relative to the center of the bistable composite laminated cylindrical shell; the magnetization direction of the four magnetic soft structures on the upper and lower surfaces connected to the straight edges should be along the tangent direction of the cylindrical shell surface and inward relative to the center of the bistable composite laminated cylindrical shell.

[0064] Under the aforementioned magnetization direction, when the magnetic actuator is in its first steady state, the magnetic soft structure is subjected to an upward vertical magnetic field, resulting in a torque on the overall structure due to the magnetic torque. Figure 3 This aligns with (a), meaning the straight-edge torque is outward relative to the cylindrical shell, and the curved-edge torque is inward relative to the cylindrical shell, which can drive the embedded bistable composite laminated cylindrical shell to transition from the first stable state to the second stable state. In this embodiment, the uniform magnetic field is 250 mT.

[0065] Under the aforementioned magnetization direction, when the magnetic actuator is in the second steady state, the magnetic soft structure is subjected to a downward vertical magnetic field and, under the influence of magnetic torque, generates torque on the overall structure. Figure 3 This aligns with (b), meaning that the straight-side torque is outward relative to the cylindrical shell, while the curved-side torque is inward relative to the cylindrical shell, which can drive the embedded bistable composite laminated cylindrical shell to transition from the second stable state to the first stable state.

[0066] When the magnetic actuator provided in this application is used, under the action of an applied magnetic field, the magnetized particles in the magnetic soft structure are subjected to magnetic torque, which causes the magnetic soft structure to deform. When the deformation is large enough, the embedded bistable composite laminated cylindrical shell spontaneously transforms to another stable state. After the deformation is completed, even if the magnetic field is removed, the magnetic actuator can autonomously maintain the deformed state.

[0067] The magnetic actuator provided in this application, by introducing a bistable composite laminated cylindrical shell, endows the magnetic soft structure with bistable characteristics. This ensures sufficient deformation while improving the deformation response speed, and enables it to spontaneously maintain the stable state after deformation without the need for continuous input of external loads, thus reducing the energy consumption required for driving and maintaining deformation. In addition, after optimizing the magnetization direction of the magnetic soft structure, the magnetic torque experienced by each part of the magnetic actuator under the action of an external magnetic field is more in line with the deformation law of the bistable composite laminated cylindrical shell, which can also reduce the driving magnetic field, thereby further reducing the driving difficulty and driving energy consumption.

[0068] like Figure 5 As shown, this application provides a method for fabricating a bistable magnetic actuator, comprising:

[0069] S1. Mix the uncured soft substrate material liquid with magnetic particles and stir evenly to obtain a magnetic mixture fluid;

[0070] S2. Inject the magnetic mixture fluid into a cuboid mold, perform injection molding and curing, and after static curing, obtain an unmagnetized cuboid magnetic soft structure. The static curing time is 1-2 hours.

[0071] S3. The unmagnetized cuboid magnetic soft structure is placed in a uniform pulsed magnetic field for magnetization to obtain a cuboid magnetic soft structure with a specific magnetization direction.

[0072] S4. Cut the uncured composite single-layer board according to the preset laying angle, and then lay it up according to the preset laying method to obtain an uncured anti-symmetric composite laminate; the preset laying angle is 40°-60°.

[0073] S5. Cut the cuboid magnetic soft structure with a specific magnetization direction obtained in S3 into a preset shape and magnetization direction, and use the same uncured soft substrate material liquid as in S1 as an adhesive to bond all the magnetic soft structures with preset shapes and magnetization directions to the upper and / or lower surfaces of the uncured antisymmetric composite material laminate obtained in S4 in a preset manner to obtain an uncured magnetic actuator.

[0074] S6. Place the uncured magnetic actuator in a cylindrical mold and heat it to cure, thereby obtaining a magnetic actuator with bistable characteristics.

[0075] In a preferred embodiment, the magnetization in step S3 uses a short-time pulsed magnetic field of 2T for several seconds. After magnetization, the magnetic particles have the same magnetization direction, resulting in a fixed magnetization direction for the cuboid magnetic soft structure. The strong magnetic field of 2T ensures the uniformity of the magnetization direction of the magnetized particles.

[0076] In a preferred embodiment, the short-time pulse magnetic field generator includes a power supply, a power control system, and an electromagnetic coil.

[0077] As a preferred embodiment, in step S1, 3D printing can be used to prepare the mold; and when designing the mold size, the size of the magnetic soft structure must be fully considered and sufficient margin must be left.

[0078] As a preferred embodiment, a degassing mixer can be used during mixing. The mixing speed is 2000 r / min, and the mixing time is 2 min. After mixing, the mixture is degassed at a speed of 2200 r / min for 1.5 min.

[0079] In a preferred embodiment, when injecting the magnetic mixture fluid into the mold in step S2, care should be taken to ensure that the fluid viscosity is high to avoid excessively fast injection speed and the formation of air bubbles and cavities; similarly, care should be taken to ensure that the fluid solidifies quickly after mixing to avoid excessively slow injection speed, which would cause the fluid viscosity to increase rapidly, making the injection process difficult and generating additional air bubbles and cavities.

[0080] As a preferred embodiment, after the magnetic mixture fluid is injected into the mold, a scraper is used to remove excess fluid to ensure a smooth injection surface.

[0081] As a preferred embodiment, after complete filling, the magnetic mixture fluid should be allowed to stand at room temperature for 4 hours or heated at 60°C for 45 minutes to fully solidify.

[0082] As a preferred embodiment, the magnetization process is as follows: The mold and the still-exposed fully cured magnetic soft structure are placed together in the pulsed magnetic field generator according to the pre-designed magnetization direction. It should be noted that the mold and the still-exposed fully cured magnetic soft structure should be completely fixed before magnetization to prevent displacement and deformation during the magnetization process. A 2T pulsed magnetic field is then applied to the entire structure for magnetization. It should be noted that the solenoid coil used should be long enough to ensure that the magnetic field around all parts of the magnetic soft structure remains uniform during magnetization.

[0083] The state of magnetic particles in the magnetic soft structure before and after magnetization is as follows: Figure 6 As shown. After magnetization is completed, the magnetic particles are magnetized in the same direction. Under the action of an external driving magnetic field, they can generate magnetic torques in the same direction, thereby causing the magnetic soft structure to produce predictable elastic deformation.

[0084] As a preferred embodiment, in step S4, the composite single-layer plate should be selected as a fiber-reinforced composite material with a single fiber direction, such as unidirectional carbon fiber / epoxy resin.

[0085] As a preferred embodiment, the magnetic actuator described in this application is cylindrical, therefore, when cutting the composite single-layer plate, it should be cut into a rectangle according to the layup method and layup angle.

[0086] In a preferred embodiment, in step S5, when selecting the adhesive, the same uncured soft substrate liquid as in S1 should be chosen, and the curing method and environmental conditions should be the same as in step S2, ensuring sufficient bonding effect while maintaining similar mechanical properties of the soft structure. Furthermore, when using the adhesive for bonding, the surface of the magnetic soft structure should be appropriately compressed to prevent air bubbles from forming and affecting the bonding effect.

[0087] In a preferred embodiment, in step S6, before heating and curing the uncured magnetic actuator, it should be pre-bent on the surface of the cylindrical mold to make it fit completely with the cylindrical mold, and at the same time, it should maintain this shape and be completely fixed to prevent it from detaching and deforming during heating; during heating and curing, the heating temperature is 120℃-150℃ and the heating time is 30min-45min; and during the heating process, it should be ensured that all parts of the magnetic actuator are heated evenly to prevent local overheating and deformation.

[0088] like Figure 7 As shown, this application also provides a driving method for the above-mentioned bistable magnetic actuator, wherein the curled side is flattened and fixed in a fixture. Figure 7 As shown in (a), when the magnetic actuator transitions from the first steady state to the second steady state, a uniform upward magnetic field needs to be applied. Utilizing the magnetic torque, the curved edges flatten inwards and the straight edges bend outwards. After reaching a certain degree of deformation, the magnetic actuator will automatically jump from the first steady state to the second steady state. After the driving magnetic field is removed, the magnetic actuator will autonomously maintain the shape of the second steady state. Figure 7 As shown in (b), similarly, when the magnetic actuator transitions from the second steady state to the first steady state, a uniform downward magnetic field needs to be applied. The magnetic torque on each side is opposite to that during the transition from the first to the second steady state. However, similarly, the straight edges bend outwards, and the curved edges flatten inwards. After reaching a certain degree of deformation, the magnetic actuator will automatically jump from the second steady state to the first steady state. After the driving magnetic field is removed, the magnetic actuator will autonomously maintain the shape of the first steady state. This method provides effective fixation while significantly reducing the driving load, i.e., the driving magnetic field, of the magnetic actuator.

[0089] Based on the above embodiments, this application provides a flexible gripper composed of a fixed clamp and two bistable magnetic actuators, such as... Figure 8As shown. The magnetization directions of each region of the two magnetic actuators should be opposite to each other, so that under the action of a magnetic field in the same direction, they will generate magnetic torques in opposite directions, causing them to curl up or unfurl simultaneously. Both magnetic actuators are flattened on one side and fixed in a fixture.

[0090] When the two magnetic actuators are in the first steady state, the gripper is in the open state, such as... Figure 8 As shown in (a); when the two magnetic actuators are in the second steady state, the gripper is in a closed state, as shown in (a). Figure 8 As shown in (b), it can grasp the object to be grasped, and based on the elastic and flexible structure of the magnetic actuator, it can grasp objects of different shapes and ensure a certain degree of adaptability without causing damage to the grasped object.

[0091] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0092] Furthermore, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0093] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after connection. "Rotary connection" refers to a connection where the components can rotate relative to each other after connection. "Sliding connection" refers to a connection where the components can slide relative to each other after connection. The directional terms mentioned in the embodiments of this application, such as "top," "bottom," "inner," "outer," "left," and "right," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0094] Furthermore, the mathematical concepts mentioned in the embodiments of this application, such as symmetry, equality, parallelism, and perpendicularity, are limitations specific to the current technological level, rather than absolute and strict mathematical definitions. Slight deviations are permissible; approximations of symmetry, equality, parallelism, and perpendicularity are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. "A and B are perpendicular" means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0095] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A bistable magnetic actuator, characterized in that, include: A bistable composite material layer and a magnetic soft layer covering the upper and / or lower surfaces of the bistable composite material layer; The bistable composite material layer is a laminated cylindrical shell structure; The magnetic soft layer includes uniformly laid magnetic particles, which are magnetized before curing. The magnetic soft layer has a cuboid structure and adapts to a cylindrical shell shape as the bistable composite material layer is cured. The cuboid structure is divided into four regions along the diagonal. The first and third regions are the same and opposite to each other, and the second and fourth regions are the same and opposite to each other. When the bistable magnetic actuator is in the first stable state, the magnetization directions of the first and third regions are along the axial direction of the surface of the bistable composite material layer and outward relative to the center of the laminated cylindrical shell; the magnetization directions of the second and fourth regions are along the circumferential direction of the surface of the bistable composite material layer and inward relative to the center of the laminated cylindrical shell. When the bistable magnetic actuator is in the second stable state, the magnetization directions of the second and fourth regions are along the axial direction of the surface of the bistable composite material layer and are inward relative to the center of the laminated cylindrical shell; the magnetization directions of the first and third regions are along the circumferential direction of the surface of the bistable composite material layer and are outward relative to the center of the laminated cylindrical shell.

2. The bistable magnetic actuator as described in claim 1, characterized in that, The thickness of the magnetic soft layer is 0.5mm-1mm.

3. The bistable magnetic actuator as described in claim 1, characterized in that, The unidirectional fiber-reinforced composite material in the bistable composite material layer is laid out in an antisymmetric manner.

4. The bistable magnetic actuator as described in claim 1, characterized in that, The bistable magnetic actuator exhibits a cylindrical shell shape in both stable states, and the bending direction is the same in both stable states.

5. The bistable magnetic actuator as described in any one of claims 1 to 4, characterized in that, The bistable magnetic actuator is used in flexible grippers or multistable robots.

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