Sensible underwater bionic mechanical gripper and manufacturing method thereof

Abstract

The invention relates to the technical field of underwater bionic mechanical equipment, in particular to a sensing underwater bionic mechanical gripper and a manufacturing method thereof. The grabbing hand comprises a supporting assembly and three grabbing assemblies connected in parallel. Each grabbing assembly is composed of a supporting module, a driving module, a sensing module and a power supply control module. The supporting module is used for hinging the three hardened layers into a double-joint linkage structure through a pre-stretching elastic hinge layer; the driving module comprises two self-healing electrostatic hydraulic drivers which are both of elastic bag-shaped structures, liquid dielectric insulating oil is injected into the drivers, silver electrodes are arranged on the surfaces of the drivers, and the drivers are fixed to the elastic hinge sides between the hardened layers respectively. The sensing module is a customized porous conductive sponge sensor and is used for monitoring contact force; the power supply control module achieves power supply and cooperative control, and the supporting assembly fixes the grabbing assemblies and the power supply control module. According to the robot, rigid driving equipment is not needed, the self-repairing capacity and the real-time sensing function are achieved, the robot can adapt to the complex underwater environment, the grabbing stability is improved, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of underwater biomimetic mechanical equipment technology, and in particular to a sensor-enabled underwater biomimetic mechanical gripper and its manufacturing method. Background Technology

[0002] Driven by the needs of marine development, underwater robots have become core equipment for exploring marine resources and carrying out seabed operations. As the "execution terminal" of robots, the performance of underwater mechanical grippers is particularly important in object grasping, manipulation, and precision operations. Compared with traditional land-based operation scenarios, the underwater environment is characterized by high pressure, corrosiveness, and unstructured features, which places three core requirements on mechanical grippers: "flexible adaptation," "real-time perception," and "long-term stability."

[0003] However, existing underwater mechanical grippers have significant shortcomings: 1. Traditional grippers often have rigid drive systems, making it difficult to achieve flexible and efficient coordinated control; 2. The separation of the sensing and drive systems leads to system complexity, feedback delays, and an inability to efficiently grasp and perceive the status in real time; 3. They lack environmental adaptability and self-healing capabilities, making it difficult to operate stably in harsh deep-sea environments for extended periods.

[0004] To overcome the limitations of rigid actuation, electrostatic hydraulic actuators have shown significant advantages in the field of soft actuation due to the synergistic effect of flexible shell and liquid dielectric. They redistribute the internal liquid dielectric through Maxwell stress between electrodes, enabling precise deformation and combining high ductility with low energy consumption, thus providing a new path for underwater flexible actuation. Among existing related research and technologies, patent 2024107687136 discloses a water-based oscillating propeller driven by electrostatic hydraulics, which uses a single electrostatic hydraulic actuator to drive a bionic fish tail to oscillate left and right to simulate fish propulsion; patent 2024104140122 designs an underwater bionic flexible actuator, which realizes the up and down oscillation of the pectoral fin by stacking multiple electrostatic hydraulic actuators; patent 2023113467815 further optimizes the actuator structure and uses rigid electrodes to improve the output force, but there is no significant improvement; in the article "Hydraulically amplified self-healing electrostatic actuators with muscle-like performance", the research team made a soft gripper by stacking multiple electrostatic hydraulic actuators, which can grasp regular objects such as eggs and strawberries; in the article "Spider-Inspired Electrohydraulic Actuators for Fast Soft-Actuated Joints", the research team developed a spider-like electrohydraulic soft-drive gripper using a single electrostatic hydraulic actuator, and through multiple sets of experiments, clarified the correspondence between the rotation angle and output force of grippers of different specifications.

[0005] However, the aforementioned electrostatic hydraulic drive technology still fails to meet the core requirements of underwater mechanical grippers: on the one hand, conventional actuators are prone to seal failure due to pressure differences in underwater environments, making long-term stable operation impossible; on the other hand, existing solutions do not integrate real-time sensing functions, making it impossible to perceive the magnitude and distribution of contact force during the gripping process, and have not yet achieved "drive-sensor" closed-loop control, making it difficult to directly apply to precise underwater gripping scenarios. To address the shortcomings of existing technologies, this invention proposes a sensor-enabled biomimetic underwater mechanical gripper. By integrating self-healing flexible drive and sensing into a single design, it can both perceive the gripping status in real time and output adjustable driving force through a self-healing electrostatic hydraulic actuator, effectively adapting to different object shapes and complex underwater environments. Simultaneously, relying on self-healing materials and a flexible drive mechanism, it improves the equipment's lifespan and environmental adaptability, providing a reliable solution for precision underwater operations. Summary of the Invention

[0006] This invention aims to solve the problems existing in current mechanical grippers and provides a sensing underwater biomimetic mechanical gripper and its manufacturing method. The technical solution is as follows:

[0007] The present invention provides a sensing underwater biomimetic mechanical gripper, comprising a support component and three parallel gripping components connected thereto; the top surface of the support component has a pre-reserved mounting groove for fixing a power supply control module, and the side surface has a pre-reserved adhesive area for fixing the gripping components.

[0008] The gripping assembly includes a support module, a drive module, a sensing module, and a power supply control module. These modules are electrically interconnected to form a closed-loop control link. The drive module and sensing module are directly mounted on designated positions within the support module, with the drive module corresponding to the joint area and the sensing module corresponding to the gripping end. The power supply control module is fixed in a pre-reserved mounting slot on the top of the support assembly and is electrically connected to both the drive module and the sensing module via two independent sets of wires. One set of wires provides high-voltage DC power to the drive module, while the other set transmits and provides feedback on the resistance signal from the sensing module. All wires are led out through waterproof sealed connectors to prevent leakage or water ingress in underwater environments.

[0009] The support module provides rigid support for the grasping action and is the foundation for realizing joint linkage. The structure includes a first upper hardened layer, a second middle hardened layer, and a third lower hardened layer arranged from top to bottom, as well as a pre-stretched elastic hinge layer for hinged connection between adjacent hardened layers. During assembly, the lower edge of the first upper hardened layer is bonded to the upper edge of the second middle hardened layer, and the lower edge of the second middle hardened layer is bonded to the upper edge of the third lower hardened layer through the inner side of the pre-stretched elastic hinge layer, forming two joints to realize dual-joint linkage.

[0010] The drive module, used to drive the gripping and releasing actions of the mechanical gripper, includes a first self-healing electrostatic hydraulic actuator and a second self-healing electrostatic hydraulic actuator, both manufactured using the same process. The first self-healing electrostatic hydraulic actuator is attached to one side of the pre-stretched elastic hinge layer of the first upper hardened layer and the second middle hardened layer using flexible double-sided adhesive, with the bottom of the first self-healing electrostatic hydraulic actuator coinciding with the bottom of the pre-stretched elastic hinge layer. The second self-healing electrostatic hydraulic actuator is symmetrically attached to one side of the pre-stretched elastic hinge layer of the second middle hardened layer and the third lower hardened layer using flexible double-sided adhesive, with the bottom of the second self-healing electrostatic hydraulic actuator coinciding with the bottom of the pre-stretched elastic hinge layer. The first and second self-healing electrostatic hydraulic actuators, along with the first upper, second middle, and third lower hardened layers, are arranged symmetrically in the vertical direction.

[0011] The sensing module is a customized porous conductive sponge sensor, its core being a three-dimensional porous structure containing a graphene conductive network. When the sensor comes into contact with an object, the contact force compresses the porous structure, increasing the contact area and shortening the conductive path of the internal graphene conductive pathways, causing the sensor resistance to decrease as the contact force increases. Conversely, when the contact force decreases or is removed, the porous structure rebounds under the action of elastic restoring force, the graphene conductive network returns to its initial state, and the resistance increases again. This resistance signal is amplified and noise-filtered by the signal processing circuit of the power supply control module, and then converted into a digital signal by the analog-to-digital converter chip and input to the control circuit. Through a preset resistance-force calibration curve, the magnitude and distribution information of the contact force can be calculated in real time, providing feedback for the dynamic adjustment of the drive module.

[0012] The power supply control module is used to realize the power supply and coordinated control of the drive module and the sensing module, including a power supply unit, a signal processing circuit, and a control circuit. The power supply unit provides high-voltage DC power to each module of the system; the signal processing circuit amplifies, bandpass filters, and performs analog-to-digital conversion on the resistance signal output by the sensing module to generate a standardized digital signal that is input to the control circuit; the control circuit adjusts the drive voltage and current parameters of the drive module in real time based on the information fed back from the sensing module, so as to achieve precise control of the dual-joint drive angle.

[0013] The self-healing electrostatic hydraulic actuator, designed to meet the dual-joint linkage requirements of the gripper, features a customized bag-like structure. The interior forms a sealed cavity capable of holding liquid dielectric insulating oil, facilitating precise alignment and bonding with the hardened layer of the support module via flexible double-sided adhesive, while also providing directional selective constraint for joint movement. The actuator is manufactured using an elastic film and silver electrodes as core materials: the elastic film is formed into a rectangular liquid reservoir with an injection port using CNC hot pressing technology. The reservoir is divided into an electrode area and a fluid deformation area along its length, with a skirt around the perimeter to prevent electric arcing, and a horizontally extending filling port on one side. The silver electrodes are symmetrically printed on both sides of the electrode area of ​​the reservoir using a microcircuit printer, and after drying and curing in a constant-temperature oven, they are firmly attached to the surface of the reservoir, possessing elasticity and flexibility adapted to the reservoir. Liquid dielectric insulating oil is then filled through the pre-reserved filling port using a syringe, ensuring the reservoir is uniformly filled with liquid dielectric insulating oil. Finally, the filling port is sealed using a welding tool.

[0014] Furthermore, during the hot pressing process of the elastic film, the heat-sealing layer faces inward and the hydrophilic layer faces outward, covered by a polyimide film to prevent sticking.

[0015] Furthermore, when not in operation, the self-healing electrostatic hydraulic actuator is flat, with a horizontal hardened layer and an elastic bag-like structure with an arc length of [missing information]. ( (Pre-stretch amount), the liquid dielectric insulating oil is uniformly distributed within the bag cavity. When a kilovolt-level DC high voltage is applied, based on the Maxwell stress effect, the positive and negative electrodes attract and close, forcing the liquid dielectric within the cavity to be pumped to the non-electrode region, causing this region to expand radially, driving the hardened layer to bend at an angle θ, and the hinge layer to continue stretching, with the lengths of the arched region and the horizontal region satisfying...

[0016] A method for manufacturing a sensor-enabled underwater biomimetic mechanical gripper includes:

[0017] Step 10, Prepare the support module: Cut the acrylic sheet into shape using a CNC laser engraving machine. The first upper hardening layer and the second middle hardening layer are standard rectangular structures, while the third lower hardening layer has a gradually shrinking design. The three parts are bonded and hinged together as one unit by a pre-stretched elastic hinge layer.

[0018] Step 20, Preparation of the driving module: The elastic film is arranged with the heat-sealed layer facing inward and the hydrophilic layer facing outward, covered with a polyimide film for anti-sticking treatment, and then processed into a rectangular liquid storage bag with an injection port by CNC hot pressing technology. A skirt is reserved around the perimeter of the bag for arc prevention, and a horizontally extended filling port is set on one side; the silver electrode is symmetrically printed on both sides of the electrode area of ​​the bag by a microcircuit printer, and after being dried and cured in a constant temperature oven, it is firmly attached to the surface of the bag.

[0019] Step 30, Module Assembly: Adhere the bag without liquid dielectric insulating oil to the support module using flexible double-sided adhesive tape. Fill the bag with liquid dielectric insulating oil through the pre-reserved filling port using a syringe, so that the inside of the bag is evenly filled with liquid dielectric insulating oil. Finally, seal the filling port using a welding tool.

[0020] Step 40, Preparation of the Sensing Module: First, grind NaCl into a fine powder in a mortar; then add graphene and continue grinding until homogeneous. Next, add deionized water and anhydrous ethanol to the mortar, mix thoroughly, and pour the mixture into a mold. Bake in an oven to form a block structure. After the salt block cools, pour it into Ecoflex0050 material and vacuum to remove air bubbles. After Ecoflex0050 solidifies, remove the surface silicone and cut into small pieces. Finally, place these small pieces in water to dissolve NaCl, and dry to obtain a customized porous conductive sponge sensor.

[0021] Step 50, Module Assembly: After waterproofing, the customized porous conductive sponge sensor is bonded to the tail of the third lower hardened layer to complete the gripping component;

[0022] Step 60, gripper assembly: Attach the three gripper components to the pre-reserved adhesive area on the side using flexible double-sided adhesive to complete the assembly.

[0023] In a preferred embodiment, in step 10, the pre-stretched elastic hinge layer is a PDMS film.

[0024] In a preferred embodiment, in step 20, the elastic film is a BOPP film.

[0025] In a preferred embodiment, in step 30, the liquid dielectric insulating oil is Envirotemp FR3, and the flexible double-sided adhesive is a PET transparent film.

[0026] In a preferred embodiment, in step 40, the amount and specifications of the materials used in the preparation of the customized porous conductive sponge sensor are specified as follows: 10g of NaCl is required as the porous framework raw material for the salt template, and 0.2g of graphene is used to construct the conductive network of the sensor; to ensure that NaCl and graphene are mixed evenly and form a paste system that can be poured into the mold, 0.5mL of deionized water and 0.5mL of anhydrous ethanol are added for adjustment; the salt template is formed by a mold with a size of 50mm×50mm×5mm, and liquid Ecoflex 0050 silicone is used as the sensor matrix material. The amount of silicone is required to completely immerse the salt template to ensure the subsequent molding effect; after the silicone is cured and cut, a sensor product with a size of 10mm×10mm×2mm is finally formed to meet the installation requirements of the tail of the third lower hardened layer.

[0027] In a preferred embodiment, the support component is a truncated triangular structure made of thick black acrylic sheet by laser cutting.

[0028] The working principle of this invention is as follows:

[0029] Step 10: In the initial state, the three gripping components are in an open posture (double-joint horizontal), the pre-stretched elastic hinge layer stores elastic potential energy, and the self-healing electrostatic hydraulic actuator is in a flat shape (arc length) When the power supply control module receives the gripping command, it simultaneously applies a kilovolt-level DC voltage to the first and second self-healing electrostatic hydraulic actuators of the three gripping components. Based on the Maxwell stress effect, the silver electrodes attract and squeeze the electrode area, forcing the liquid dielectric insulating oil to flow into the fluid deformation area, driving the deformation area to expand radially.

[0030] Step 20: The expansion force is transmitted to the hardened layer through the pre-stretched elastic hinge layer, causing the joints between the first upper hardened layer and the second middle hardened layer to bend by an angle θ, and the joints between the second middle hardened layer and the third lower hardened layer to bend by an angle θ, forming a double-joint linkage grasping posture. The three grasping components are controlled by the phase difference of the power supply control module, adjusting their respective bending angles according to the contour of the target object (e.g., a symmetrical wrapping posture when grasping a sphere, and differentiated bending when grasping irregular objects).

[0031] Step 30: When the customized porous conductive sponge sensor at the tail of the third lower hardened layer contacts the object, its resistance signal is processed and fed back to the control circuit. If the contact force is less than the target value, the control circuit increases the driver voltage to enhance the bending degree; if the contact force exceeds the threshold, the voltage is reduced to avoid excessive force damage. Stable gripping is achieved through closed-loop control.

[0032] Step 40: After the gripping is completed, the power supply control module cuts off the voltage and releases the residual charge. The elastic restoring force of the pre-stretched elastic hinge layer drives the double joints to reset. The liquid dielectric insulating oil flows back to restore the driver to its flat shape. The three gripping components open synchronously to complete the release action.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] (1) The spider-inspired mechanical gripper is based on the self-healing electrostatic hydraulic drive principle and adopts a dual-joint collaborative drive structure design. Through phase difference regulation technology integrated into the power supply control module, the bending angle of the three gripping components can be dynamically adjusted. (2) The elastic film and pre-stretched elastic hinge layer adopt specific flexible materials and flexible structures, which are elastic and chemically resistant. The elastic film enables the self-healing electrostatic hydraulic actuator to have rapid recovery capability, and combined with the gradient hardening layer, it achieves a lifespan of tens of thousands of cycles. The pre-stretched elastic hinge layer provides elastic recovery force, which can maximize the utilization of energy. (3) The fingertip sponge sensor collects stress signals in real time and dynamically adjusts the drive voltage to improve the gripping stability of complex-shaped objects. Attached Figure Description

[0035] Figure 1a This is a schematic diagram of the structure after the component is created.

[0036] Figure 1b This is a schematic diagram of the structure after the component is installed.

[0037] Figure 1c This is a schematic diagram of the structure after the component is actuated.

[0038] Figure 1d To capture the front view of the component.

[0039] Figure 1e To capture the top view of the component.

[0040] Figure 2 This is a schematic diagram of the supporting components and power supply control module.

[0041] Figure 3 A flowchart for creating the component.

[0042] Figure 4 This is a schematic diagram of a mechanical gripper structure.

[0043] Figure 5 This is a schematic diagram of a mechanical gripper grasping an object.

[0044] Figure 6a A schematic diagram of the actuation principle of the grabbing component.

[0045] Figure 6b Schematic diagram of the actuation principle of the grabbing component Figure 2 .

[0046] Figure 7 This is a schematic diagram of the actuation principle of a self-healing electrostatic hydraulic actuator.

[0047] Figure 8 This is a flowchart illustrating the manufacturing process of a sponge sensor.

[0048] Reference numerals: 1. Support component; 2. Gripping component; 21. Drive module; 211. First self-healing electrostatic hydraulic actuator; 212. Second self-healing electrostatic hydraulic actuator; 213. Flexible double-sided adhesive; 2111. Elastic film; 2112. Liquid dielectric insulating oil; 2113. Silver electrode; 22. Sensing module; 221. Customized porous conductive sponge sensor; 23. Support module; 231. First upper hardened layer; 232. Second middle hardened layer; 233. Third lower hardened layer; 234. Pre-stretched elastic hinge layer; 24. Power supply control module; Detailed Implementation

[0049] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0050] Example 1

[0051] This embodiment provides a sensing underwater biomimetic mechanical gripper, the structure of which is as follows: Figure 1a , 1b 1c, 1d, 1e Figure 4 As shown, it includes a support component 1 and three parallel gripping components 2; the gripping component 2 consists of a support module 23, a drive module 21, a sensing module 22, and a power supply control module 24. The specific preparation and assembly steps are as follows:

[0052] Step 10: The support module 23 is a double-joint linkage structure used to support the drive module 21 and the sensing module 22. Its fabrication process is as follows: A 1mm thick acrylic sheet is cut using a CNC laser engraving machine to form a first upper hardened layer 231, a second intermediate hardened layer 232, and a third lower hardened layer 233. The first upper hardened layer 231 and the second intermediate hardened layer 232 are both standard rectangles of 45mm × 40mm. The third lower hardened layer 233 has a front end of 10mm × 40mm and a gradually tapering tail end to 10mm. A 0.4mm thick PDMS film is selected as the pre-stretched elastic hinge layer 234. After pre-stretching, it is repeatedly bent to eliminate residual stress. During assembly, the lower edge of the first upper hardened layer is bonded to the upper edge of the second intermediate hardened layer, and the lower edge of the second intermediate hardened layer is bonded to the upper edge of the third lower hardened layer through the inner side of the pre-stretched elastic hinge layer (234), forming two joints to achieve double-joint linkage (corresponding to...). Figure 1a , 1d ).

[0053] Step 20: The drive module 21 includes a self-healing electrostatic hydraulic actuator 211 and a self-healing electrostatic hydraulic actuator 212, used to drive the dual joints to achieve grasping and releasing actions. Its preparation process is as follows: A 30μm thick BOPP film 2111 is used, and two layers of film are hot-pressed into a 45mm×40mm rectangular liquid storage bag using a CNC heat-sealing machine. This bag is divided along its length into a 25mm×34mm electrode area and a 20mm×34mm fluid deformation area, with a 1mm wide skirt reserved at the periphery to prevent electric arcing. Silver electrodes 2113 are printed on both sides of the electrode area of ​​the bag using a microcircuit printer, with the electrode pattern matching the size of the electrode area. After printing, it is placed in a constant temperature oven to dry, ensuring the electrodes are cured and adhered. Envirotemp FR3 dielectric oil 2112 is injected into the bag through the injection port using a micro-injection pump, with the injection volume being 80% of the bag's volume. The injection port is then sealed using a heated welding tool to form a sealed cavity (corresponding to...). Figure 7 (2111 wrapped area); finally, the first self-healing electrostatic hydraulic actuator 211 is symmetrically attached to one side of the pre-stretched elastic hinge layer 234 between the first upper hardened layer 231 and the second intermediate hardened layer 232 using flexible double-sided adhesive 21 (corresponding to Figure 1a Position 211), the second self-healing electrostatic hydraulic actuator 212 is symmetrically attached to one side of the pre-stretched elastic hinge layer 234 between the second intermediate hardened layer 232 and the third lower hardened layer 233 (corresponding to position 211). Figure 1a Position 212), ensure the centerline of the drive is aligned with the hinge axis (corresponding to...). Figure 1a , 1c , Figure 7 ).

[0054] Step 30: The sensing module 22 is a customized porous conductive sponge sensor 221 used to monitor grasping force. Its preparation and installation process is as follows: 10g of NaCl is ground into a fine powder in a mortar, 0.2g of graphene is added, and grinding continues until uniformly mixed; 0.5mL of deionized water and 0.5mL of anhydrous ethanol are added to the mixture, stirred to form a paste, and then poured into a 50mm×50mm×5mm mold. The mold is baked in an oven until a block-shaped salt template is formed; after the salt template cools to room temperature, it is completely immersed in liquid Ecoflex. In 0050 silicone, a vacuum chamber is placed to remove air bubbles; after the silicone cures at room temperature, excess silicone is peeled off, and the material is cut into small pieces of 10mm×10mm×2mm. These pieces are then soaked in water to dissolve NaCl, resulting in a porous structure. Finally, the material is dried in an oven to form a customized porous conductive sponge sensor 221. After wrapping the surface of the customized porous conductive sponge sensor with a waterproof layer, the sensor is bonded to the tail of the third lower hardened layer 233 (corresponding to...) using flexible double-sided adhesive 213. Figure 1a , 1c , Figure 8 ).

[0055] In this embodiment, in step 30, the working principle of the customized porous conductive sponge sensor is based on the "force-resistance" coupling effect: within its interconnected porous structure, graphene is uniformly distributed to form a conductive network. When grasping an object, the sensor at the tail of the third lower hardened layer deforms upon contact with the object, compressing the porous structure and increasing the contact points between graphene particles, thus reducing the resistance of the conductive path; the greater the contact force, the greater the compression, and the more significant the resistance decrease. The waterproof sensor can operate stably in underwater environments, and the resistance signal change is transmitted to the power supply control module via wires, enabling real-time monitoring and feedback of the contact force.

[0056] Step 40: The power supply control module 24 and the support assembly 1 are used to realize power supply, signal processing, and overall structural fixation. The assembly process involves using a high-voltage power supply, signal processing circuit, and control circuit, fixing them to an acrylic substrate, and encapsulating them in a waterproof box (corresponding to...). Figure 2 (Mark 24 in the middle); a thick acrylic sheet is selected and laser-cut into a regular triangular frustum with a top base of 22mm, a bottom base of 40mm, and a height of 10mm as support component 1, with a pre-reserved mounting groove at the top (corresponding to...). Figure 2 The top of the support component 1 has a 20mm x 10mm adhesive area along each of the three edges; finally, the three gripping components 2 are symmetrically fixed to the adhesive areas on the sides of the support component using flexible double-sided adhesive 213. The power supply control module 24 is embedded in the top mounting slot, and the wires connect the driver electrode 2113 and the customized porous conductive sponge sensor 221. The interface is sealed with silicone, completing the overall assembly of the mechanical gripper (corresponding to...). Figure 2 , Figure 4 ).

[0057] In a specific implementation, the assembled mechanical gripper has the following overall structure: Figure 4 As shown: The power supply control module 24 is fixed in the mounting groove at the top of the support component 1. The three edge adhesive areas on the side are each fixed with a gripping component 2 by flexible double-sided adhesive 213. The three gripping components 2 are symmetrically distributed at 120° to ensure balanced force during gripping.

[0058] Example 2

[0059] This embodiment provides the working principle of the above-mentioned mechanical gripper, as detailed below (corresponding to Figure 1). Figure 6a , 6b ):

[0060] When high pressure is applied to the self-healing electrostatic hydraulic actuators 211 and 212, the silver electrode 2113 gradually attracts under Maxwell stress, and electrostatic energy is converted into hydraulic energy, which pushes the liquid dielectric insulating oil 2112 to move continuously to the other side of the flexible reservoir bag that does not cover the electrode. During this process, the electrode area gradually closes (similar to a "zipper" mechanism), and the fully compressed electrode area no longer has the ability to compress the dielectric fluid.

[0061] In the initial state (corresponding to) Figure 6a With no voltage applied to the silver electrode 2113, the bag-like structure formed by the elastic film 2111 is filled with uniform liquid dielectric insulating oil 2112. The joints between the first upper hardened layer 231, the second middle hardened layer 232, and the third lower hardened layer 233 are in a horizontal state. The pre-stretched elastic hinge layer 234 is in a pre-stretched state. The arc length of the surface of the elastic film 2111 is... ( The initial basic arc length, (This refers to the pre-stretch amount).

[0062] When the power supply control module (24) applies a DC voltage on the order of kilovolts to the silver electrode (2113) (corresponding to Figure 6b The positive silver electrode is connected to the positive terminal of the power supply, and the negative silver electrode is connected to the negative terminal of the power supply. The distance between the two silver electrodes gradually decreases until they are almost touching. The liquid dielectric insulating oil (2112) in the bag-shaped structure is pressurized and pumped to flow to the fluid deformation area without electrodes, causing the elastic film (2111) in this area to arch up, applying tension to the adjacent hardened layer, causing the joint to bend at an angle of θ. The pre-stretched elastic hinge layer (234) is in a further stretched state. At this time, the surface length of the elastic film (2111) is the sum of the horizontal segment length l and the arched segment length Z, and satisfies

[0063] After power failure, the Maxwell stress between the silver electrodes 2113 disappears, and the power supply control module 24 releases the residual charge through the discharge resistor. Under the elastic restoring force of the elastic hinge layer 234 and the fluidity of the liquid dielectric insulating oil (2112), the self-healing electrostatic hydraulic actuator 211 and the self-healing electrostatic hydraulic actuator 212 return to their initial flat shape, and the double joints reset to the horizontal state.

[0064] In a specific implementation, the collaborative grasping process of the mechanical gripper is as follows: Figure 5 As shown, when the power supply control module 24 receives the grasping command, the control circuit applies differentiated phase difference control to the drive module 21 of the three grasping components 2, so that the three grasping components eventually form a wrapping posture and achieve stable grasping of the object.

[0065] For any points not covered above, existing technologies shall apply.

[0066] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are merely illustrative and not intended to limit the scope of the invention; those skilled in the art may modify, supplement, or substitute the specific embodiments, but such modifications, supplements, or substitutions shall not depart from the direction of the invention or exceed the scope defined by the claims. All modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sensor-enabled underwater biomimetic mechanical gripper, characterized in that, The sensorable underwater biomimetic mechanical gripper includes a support component and three parallel gripping components connected thereto; the top surface of the support component has a pre-reserved mounting groove to fix the power supply and control module, and the side has a pre-reserved adhesive area to fix the gripping components. The gripping component includes a support module, a drive module, a sensing module, and a power supply control module. The modules are electrically interconnected to form a closed-loop control link. The drive module and the sensing module are directly mounted on designated positions on the support module. The drive module corresponds to the joint area, and the sensing module corresponds to the gripping end. The power supply control module is fixed in a reserved mounting slot on the top of the support component and is electrically connected to the drive module and the sensing module through two sets of independent wires. One set of wires provides high-voltage DC power to the drive module, and the other set of wires enables the transmission and feedback of the resistance signal of the sensing module. The support module provides rigid support for the grasping action and is the foundation for realizing joint linkage. The structure includes a first upper hardened layer, a second middle hardened layer, and a third lower hardened layer arranged from top to bottom, as well as a pre-stretched elastic hinge layer for hinged connection between adjacent hardened layers. During assembly, the lower edge of the first upper hardened layer is bonded to the upper edge of the second middle hardened layer, and the lower edge of the second middle hardened layer is bonded to the upper edge of the third lower hardened layer through the inner side of the pre-stretched elastic hinge layer, forming two joints to achieve dual-joint linkage. The drive module is used to drive the gripper's gripping and releasing actions. It includes a first self-healing electrostatic hydraulic actuator and a second self-healing electrostatic hydraulic actuator. The first self-healing electrostatic hydraulic actuator is attached to one side of the pre-stretched elastic hinge layer of the first upper hardened layer and the second middle hardened layer using flexible double-sided adhesive. The bottom of the first self-healing electrostatic hydraulic actuator coincides with the bottom of the pre-stretched elastic hinge layer. The second self-healing electrostatic hydraulic actuator is symmetrically attached to one side of the pre-stretched elastic hinge layer of the second middle hardened layer and the third lower hardened layer using flexible double-sided adhesive. The bottom of the second self-healing electrostatic hydraulic actuator coincides with the bottom of the pre-stretched elastic hinge layer. The first and second self-healing electrostatic hydraulic actuators and the first upper, second middle, and third lower hardened layers are symmetrically placed in the vertical direction. The self-healing electrostatic hydraulic actuator is designed as a customized bag-shaped structure to adapt to the gripper's dual-joint linkage requirements. The internal sealed cavity can accommodate liquid dielectric insulating oil, which facilitates precise alignment and bonding with the hardened layer of the support module using flexible double-sided adhesive, and also provides directional selective constraint for joint swing. The sensing module is a customized porous conductive sponge sensor; The power supply control module is used to realize the power supply and coordinated control of the drive module and the sensing module. It includes a power supply unit, a signal processing circuit, and a control circuit. The power supply unit provides high-voltage DC power to each module of the system. The signal processing circuit amplifies, bandpass filters, and performs analog-to-digital conversion on the resistance signal output by the sensing module to generate a standardized digital signal that is input to the control circuit. The control circuit adjusts the drive voltage and current parameters of the drive module in real time based on the information fed back by the sensing module to achieve precise control of the dual-joint drive angle.

2. The underwater biomimetic mechanical gripper as described in claim 1, characterized in that, All wires are led out through waterproof and sealed joints to prevent leakage or water ingress in underwater environments.

3. The underwater biomimetic mechanical gripper as described in claim 1, characterized in that, The customized porous conductive sponge sensor is a three-dimensional porous structure containing a graphene conductive network. When the sensor comes into contact with an object, the contact force compresses the porous structure, causing the contact area of ​​the internal graphene conductive pathways to increase and the conductive path to shorten, resulting in a decrease in sensor resistance as the contact force increases. Conversely, when the contact force decreases or is removed, the porous structure rebounds under the action of elastic restoring force, the graphene conductive network returns to its initial state, and the resistance rises again. This resistance signal is amplified and noise-filtered by the signal processing circuit of the power supply control module, and then converted into a digital signal by the analog-to-digital converter chip and input to the control circuit. Through the preset resistance-force calibration curve, the magnitude and distribution information of the contact force can be calculated in real time, providing feedback for the dynamic adjustment of the drive module.

4. The underwater biomimetic mechanical gripper as described in claim 1, characterized in that, When not in operation, the self-healing electrostatic hydraulic actuator is flat with a horizontal hardened layer and an elastic bag-like structure with an arc length of L+ΔL0, where ΔL0 is the pre-stretch amount. The liquid dielectric insulating oil in the bag cavity is evenly distributed. When a kilovolt-level DC high voltage is applied, based on the Maxwell stress effect, the positive and negative electrodes attract and close, forcing the liquid dielectric in the cavity to be pumped to the non-electrode area, causing the area to expand radially, driving the hardened layer to bend at an angle θ, and the hinge layer to be stretched continuously. The lengths of the arched area and the horizontal area satisfy Z+L=L+ΔL0.

5. The underwater biomimetic mechanical gripper as described in claim 1, characterized in that, The support component has a truncated triangular structure and is laser-cut from a thick black acrylic sheet.

6. The method for preparing a sensorable underwater biomimetic mechanical gripper as described in claim 1, characterized in that, The specific steps are as follows: Step 10, prepare the support module: cut the acrylic sheet into shape using a CNC laser engraving machine. The first upper hardening layer and the second middle hardening layer are standard rectangular structures, and the third lower hardening layer has a gradually shrinking design. The three parts are bonded and hinged together as one unit by a pre-stretched elastic hinge layer. Step 20, Preparation of the driving module: The elastic film is arranged with the heat-sealed layer facing inward and the hydrophilic layer facing outward, covered with a polyimide film for anti-sticking treatment, and then processed into a rectangular liquid storage bag with an injection port by CNC hot pressing technology. A skirt is reserved around the perimeter of the bag for arc prevention, and a horizontally extended filling port is set on one side; the silver electrode is symmetrically printed on both sides of the electrode area of ​​the bag using a microcircuit printer, and after drying and curing in a constant temperature oven, it is firmly attached to the surface of the bag; Step 30, Module Assembly: Adhere the bag without liquid dielectric insulating oil to the support module using flexible double-sided tape. Fill the bag with liquid dielectric insulating oil through the pre-reserved filling port using a syringe, so that the inside of the bag is evenly filled with liquid dielectric insulating oil. Finally, seal the filling port with welding tools. Step 40, Preparation of the sensing module: First, grind NaCl into a fine powder in a mortar; then add graphene and continue grinding until uniform; next, add deionized water and anhydrous ethanol to the mortar, mix thoroughly, and pour the mixture into a mold; bake in an oven to form a block structure; after the salt block cools, pour it into Ecoflex0050 material and vacuum to remove air bubbles; After Ecoflex0050 has cured, remove the surface silicone and cut it into small pieces. Finally, put these small pieces into clean water to dissolve NaCl, and after drying, you will get a customized porous conductive sponge sensor. Step 50, Module Assembly: After waterproofing, the customized porous conductive sponge sensor is bonded to the tail of the third lower hardened layer to complete the gripping component; Step 60, gripper assembly: Attach the three gripper components to the pre-reserved adhesive area on the side using flexible double-sided adhesive to complete the assembly.

7. The method for preparing a sensorable underwater biomimetic mechanical gripper as described in claim 6, characterized in that, In step 10, the pre-stretched elastic hinge layer is made of PDMS film; in step 20, the elastic film is made of BOPP film.

8. The method for preparing a sensorable underwater biomimetic mechanical gripper as described in claim 6, characterized in that, In step 30, the actuator uses an elastic film and silver electrodes as the core raw materials: the elastic film is formed into a rectangular liquid storage bag with an injection port using computer numerical control hot pressing technology. During the hot pressing process, the heat-sealing layer faces inward and the hydrophilic layer faces outward, covered with a polyimide film to prevent sticking. The bag is divided into an electrode area and a fluid deformation area along its length, with a skirt reserved at the periphery to prevent electric arc, and a horizontally extending filling port on one side. The silver electrodes are symmetrically printed on both sides of the electrode area of ​​the bag using a microcircuit printer. After drying and curing in a constant temperature oven, they are firmly attached to the surface of the bag, possessing elasticity and flexibility suitable for the bag. Then, liquid dielectric insulating oil is filled through the reserved filling port of the bag using a syringe, so that the inside of the bag is uniformly filled with liquid dielectric insulating oil. Finally, the filling port is sealed using a welding tool. The liquid dielectric insulating oil is Envirotemp FR3, and the flexible double-sided adhesive is PET transparent film.

9. The method for preparing a sensorable underwater biomimetic mechanical gripper as described in claim 6, characterized in that, In step 40, the amount and specifications of the materials used in the preparation of the customized porous conductive sponge sensor are specified as follows: 10g of NaCl is required as the porous framework raw material for the salt template, and 0.2g of graphene is used to construct the conductive network of the sensor; to ensure that NaCl and graphene are mixed evenly and form a paste system that can be poured into the mold, 0.5mL of deionized water and 0.5mL of anhydrous ethanol are added for adjustment; the salt template is formed by a mold with a size of 50mm×50mm×5mm, and liquid Ecoflex 0050 silicone is used as the sensor matrix material. The amount of silicone is required to completely immerse the salt template to ensure the subsequent molding effect; after the silicone is cured and cut, a sensor product with a size of 10mm×10mm×2mm is finally formed to fit the installation requirements of the tail of the third lower hardened layer.

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