Underwater liquid metal flexible joint driving method and device

Abstract

The underwater liquid metal flexible joint driving method comprises the steps that underwater environment parameters are collected, modular configuration of a flexible joint is completed according to the environment parameters, after the flexible joint dives to the working depth, internal and external pressure self-balancing and working face positioning are completed, and a working position and an adsorption position are obtained; an electric control adsorption system in the flexible joint is started, the flexible joint is adsorbed at an adsorption position, the flexible joint performs maintenance operation at an operation position, in the maintenance operation process, the operation state of the flexible joint is monitored in real time, after the maintenance operation is completed, the flexible joint floats upwards to be recycled, adsorption can be achieved on a concrete gate and a steel plate covered with algae, and the maintenance efficiency is improved. The adsorption adaptability to different materials and different environments is improved.

Description

Technical Field

[0001] This invention relates to the field of underwater facility maintenance technology, specifically to an underwater liquid metal flexible joint driving method and device. Background Technology

[0002] Hydropower station turbine channels, concrete gates, stainless steel runners, trash racks and other underwater facilities are in a complex environment of deep water, high pressure and turbid water for a long time. The working surfaces are also characterized by diverse materials, easy adhesion of algae and silt, and narrow working space.

[0003] Liquid metal flexible joints are a new type of biomimetic motion joint that uses room temperature liquid metal as the core functional medium, combined with a flexible matrix and a phase change control mechanism. They can achieve reversible switching between flexible deformation and rigid load bearing.

[0004] During the maintenance of existing underwater facilities, magnetic suction cannot adhere to concrete and severely corroded surfaces; negative pressure suction requires continuous drainage and fails underwater due to the small pressure difference between the inside and outside; traditional grippers have difficulty applying force to smooth surfaces covered with algae; and rigid structures have difficulty turning in narrow blade gaps or gate slots, resulting in low adaptability and low maintenance efficiency. Summary of the Invention

[0005] The present invention proposes an underwater liquid metal flexible joint driving method and device to solve the technical problems in the background art mentioned above.

[0006] This invention proposes a method for driving an underwater liquid metal flexible joint, comprising: S1. Collect underwater environmental parameters; S2. Based on environmental parameters, complete the modular configuration of the flexible joint; S3. After the flexible joint descends to the working depth, it completes the self-balancing of internal and external pressures and the positioning of the working surface, thus obtaining the working position and the adsorption position. S4. Activate the electro-controlled adsorption system in the flexible joint, adsorb at the adsorption position, and perform maintenance work on the flexible joint at the working position. S5. During the maintenance operation, the operating status of the flexible joint is monitored in real time. S6. After the maintenance work is completed, the flexible joint is floated up and retrieved.

[0007] Preferably, the environmental parameters include water depth, working surface material, and working gap size.

[0008] Preferably, S2 includes: Based on the material of the working surface, an electrically controlled adsorption system is installed on the flexible joint chassis. The electrically controlled adsorption system includes several adsorption feet. Based on the water depth and the working gap size, a multi-degree-of-freedom liquid metal pressure-resistant flexible joint robotic arm is configured. Based on the water depth, the material of the working surface, and the size of the working gap, a protection and monitoring system is configured.

[0009] Preferably, S3 includes: By utilizing the self-balancing structure of the flexible joint's internal and external pressures, the flexible joint can be matched with the underwater environment pressure in real time. The positioning system within the flexible joint first locates the adsorption position, and then locates the working position.

[0010] Preferably, S4 includes: The adsorption power supply is activated, and a high-frequency square wave voltage is output to the electrode array adsorbing the foot to establish an underwater electronically controlled adsorption force model and confirm the first adsorption force. By utilizing the Johnsen-Rahbek effect, a strong electric field was established between the electrode array and the adsorbed wall surface, confirming the second adsorption force. Adjust the flexible joint posture, place the adsorbent foot close to the wall to be inspected, and complete the adsorption based on the first and second adsorption forces; A first control current is supplied to the liquid metal channel of the robotic arm. According to the joint stiffness control formula, the joint maintains a low stiffness state and enters a narrow space to locate the fault point. After locating the fault point, the input current of the liquid metal flow channel is instantly increased to the second control current, and the robotic arm is in a highly rigid state, which, together with the end effector, completes a powerful operation.

[0011] Preferably, the formula for the underwater electro-controlled adsorption force model is as follows:

[0012] in, The first adsorption force, The effective dielectric constant includes the effect of the water film. For the applied high-frequency square wave voltage, For equivalent dielectric thickness, The vacuum permittivity, The effective relative permittivity; The formula for calculating the equivalent dielectric thickness is as follows:

[0013] in, The air gap is caused by the micro-roughness of the contact surface. The thickness of the insulating film. The effective dielectric constant of water, The relative permittivity of the insulating layer, This refers to the thickness of the residual water film.

[0014] Preferably, the formula for calculating the second adsorption force is as follows:

[0015] in, For the interface charge density, For contact resistance, For effective contact area, It is an enhancing factor.

[0016] Preferably, the joint stiffness control formula is as follows:

[0017] in, This refers to the bending stiffness of a flexible joint. This represents the initial stiffness of the elastomer substrate. The magnetic fluid pressure difference within the liquid metal flow channel. The current density in the fluid. The external magnetic field strength, The effective length of the flow channel. This is the stiffness proportionality coefficient.

[0018] Preferably, S5 includes: The leakage current is detected in real time by a microampere-level current sensor in the electrode. When the detected leakage current exceeds the preset threshold, the high-frequency square wave voltage input of the faulty sub-region is automatically cut off. A negative potential relative to the ambient water is applied to the flexible joint chassis.

[0019] A liquid metal flexible joint device, the system comprising: The data acquisition system is used to collect underwater environmental parameters. A configuration system is used to perform modular configuration of flexible joints based on environmental parameters; The positioning system is used to achieve self-balancing of internal and external pressures and positioning of the working surface after the flexible joint descends to the working depth, thereby obtaining the working position and the adsorption position. An electro-controlled adsorption and robotic arm system is used to adsorb the flexible joint at the adsorption position, and the flexible joint performs maintenance operations at the working position. A protection and monitoring system is used to monitor the operating status of the flexible joint in real time during the maintenance work. A propulsion system is used to float and retrieve the flexible joint after the maintenance work is completed.

[0020] As can be seen from the above technical solution, the present invention provides a method for driving an underwater liquid metal flexible joint. Compared with the prior art, the present invention has the following advantages: 1. This invention establishes an underwater electrically controlled adsorption force model by outputting a high-frequency square wave voltage to the electrode array that adsorbs the foot, confirming the first adsorption force. Through the Johnsen-Rahbek effect, a strong electric field is established between the electrode array and the adsorbed wall surface, confirming the second adsorption force. Adsorption is completed based on the first and second adsorption forces. Adsorption can be achieved on concrete gates and steel plates covered with algae, improving the adsorption adaptability to different materials and environments.

[0021] 2. This invention introduces a first control current into the liquid metal channel of the robotic arm. According to the joint stiffness control formula, the joint maintains a low stiffness state and enters a narrow space to locate the fault point. After locating the fault point, the input current of the liquid metal channel is instantly increased to a second control current, and the robotic arm is in a high stiffness state. It works with the end effector to complete powerful operations. The joint can wrap around the trash rack like an octopus tentacle or squeeze into the narrow gap of the turbine blade, thus improving maintenance efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of an underwater liquid metal flexible joint driving method according to the present invention; Figure 2 This is a schematic diagram of the electrostatic potential and vector field distribution of the multilayer dielectric in this invention; Figure 3 This is a schematic diagram of the magnetohydrodynamic driving field of the present invention; Figure 4 This is a schematic diagram of the dynamic performance curve of the joint bending stiffness of the present invention; Figure 5 This is a diagram showing the cathodic protection potential distribution of the present invention; Figure 6 This is a schematic diagram of the overall structure and underwater operation principle of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0024] like Figure 1 As shown in this embodiment, an underwater liquid metal flexible joint actuation method includes: S1. Collect underwater environmental parameters; S2. Based on environmental parameters, complete the modular configuration of the flexible joint; S3. After the flexible joint descends to the working depth, it completes the self-balancing of internal and external pressures and the positioning of the working surface, thus obtaining the working position and the adsorption position. S4. Start the electro-adsorption system in the flexible joint, adsorb at the adsorption position, and perform maintenance work on the flexible joint at the working position. S5. During maintenance work, monitor the operating status of the flexible joint in real time. S6. After the maintenance work is completed, the flexible joint is floated up and retrieved.

[0025] In practical applications, taking the maintenance of the deep-hole gate slide of a large hydropower station as an example, the device's operational capabilities in deep water, high pressure, and turbid environments are demonstrated. The working environment is as follows: (1) Deep hole emergency gate slot, depth 100m, ambient water pressure 10bar.

[0026] (2) The slide is made of a composite structure of concrete and stainless steel, with 2mm thick silt and algae attached to the surface.

[0027] (3) The water is turbid and the visibility is almost zero.

[0028] Environmental parameters include water depth, surface material, and working gap dimensions.

[0029] Furthermore, S2 includes: Depending on the material of the working surface, an electrically controlled adsorption system is installed on the flexible joint chassis. The electrically controlled adsorption system includes several adsorption feet. Based on the water depth and the working gap size, a multi-degree-of-freedom liquid metal pressure-resistant flexible joint robotic arm is configured; Based on the water depth, the material of the working surface, and the size of the working gap, configure a protection and monitoring system.

[0030] Specifically, the device configuration is as follows: (1) Four flexible PCB electrostatic adsorption feet (single foot area) are installed on the chassis.

[0031] (2) The robotic arm uses a 3-degree-of-freedom liquid metal pressure-resistant joint.

[0032] Furthermore, S3 includes: By utilizing the self-balancing structure of the flexible joint's internal and external pressures, the flexible joint can be matched with the underwater environment pressure in real time. The positioning system within the flexible joint first locates the adsorption position, and then locates the working position.

[0033] Specifically, the robot descends to a depth of 100m, where its internal and external pressure self-balancing structure ensures no joint deformation. The positioning system is then activated to first locate the adsorption position and then the working position.

[0034] Furthermore, S4 includes: The adsorption power supply is activated, and a high-frequency square wave voltage is output to the electrode array adsorbing the foot to establish an underwater electronically controlled adsorption force model and confirm the first adsorption force. By utilizing the Johnsen-Rahbek effect, a strong electric field was established between the electrode array and the adsorbed wall surface, confirming the second adsorption force. Adjust the flexible joint posture, place the adsorbent foot close to the wall to be inspected, and complete the adsorption based on the first and second adsorption forces; like Figure 2 As shown, the potential gradient and electric field vector distribution at the interface between the electrode array and the water film demonstrate... Regulation mechanism; A first control current is supplied to the liquid metal channel of the robotic arm. According to the joint stiffness control formula, the joint maintains a low stiffness state and enters a narrow space to locate the fault point. After locating the fault point, the input current of the liquid metal flow channel is instantly increased to the second control current, the robotic arm is in a high rigidity state, and it completes powerful operation in conjunction with the end effector. Specifically, after getting close to the surface of the slide, the adsorption power supply is activated, and output is generated. The high-frequency square wave voltage; the electric field penetrates the surface silt layer and generates induced charges on the concrete substrate; the measured normal adsorption force reaches 1200N and the shear force reaches 800N, and it can still be stably adsorbed despite the wet and slippery surface. During the positioning phase, a small current is applied to the liquid metal joint. Maintain low rigidity and flexibly probe into the gap (5cm wide) of the slide rail for inspection; After locating the work site, a foreign object was found obstructing the flow, causing the joint current to increase instantly. With an 8-fold increase in rigidity, the robotic arm becomes stiffer and, in conjunction with the end effector gripper, powerfully removes foreign objects. like Figure 3 As shown, the MHD (magnetohydrodynamic) vector driving field within the liquid metal flow channel is illustrated, demonstrating the variable stiffness pressure difference. The mechanism of its generation.

[0035] The formula for the underwater electro-hydraulic adsorption force model is as follows:

[0036] in, The first adsorption force, The effective dielectric constant includes the effect of the water film. For the applied high-frequency square wave voltage, For equivalent dielectric thickness, The vacuum permittivity, The effective relative permittivity; The formula for calculating the equivalent dielectric thickness is as follows:

[0037] in, The air gap is caused by the micro-roughness of the contact surface. The thickness of the insulating film. The effective dielectric constant of water, The relative permittivity of the insulating layer, This refers to the thickness of the residual water film.

[0038] The formula for calculating the second adsorption force is as follows:

[0039] in, For the interface charge density, For contact resistance, For effective contact area, It is an enhancing factor.

[0040] The formula for controlling joint stiffness is as follows:

[0041] in, This refers to the bending stiffness of a flexible joint. This represents the initial stiffness of the elastomer substrate. The magnetic fluid pressure difference within the liquid metal flow channel. The current density in the fluid. The external magnetic field strength, The effective length of the flow channel. This is the stiffness proportionality factor; like Figure 4 As shown, the blue curve represents the joint bending stiffness. With magnetohydrodynamic pressure difference The dynamic response curve shows that the red dashed line represents the industry standard threshold. As can be seen from the figure, the dynamic indicators of this invention are superior to the industry standard.

[0042] Furthermore, S5 includes: The leakage current is detected in real time by a microampere-level current sensor in the electrode. When the detected leakage current exceeds the preset threshold, the high-frequency square wave voltage input of the faulty sub-region is automatically cut off. like Figure 5 As shown, a negative potential relative to ambient water is applied to the cathode of the flexible joint chassis, demonstrating... The uniform distribution at the target potential demonstrates the system's robustness against corrosion under a strong electric field; Specifically, throughout the entire process, the active insulation monitoring system showed that the leakage current remained at [value missing]. The following properties indicate good insulation performance; At the moment the voltage is cut off, the adsorption force disappears within 10ms (without residual magnetism), and the robot uses the thrusters (propulsion system) to float up and recover.

[0043] like Figure 6 As shown, a liquid metal flexible joint device includes: The data acquisition system is used to collect underwater environmental parameters. A configuration system is used to perform modular configuration of flexible joints based on environmental parameters; The positioning system is used to achieve self-balancing of internal and external pressures and positioning of the working surface after the flexible joint descends to the working depth, thereby obtaining the working position and the adsorption position. An electro-controlled adsorption and robotic arm system is used to adsorb a flexible joint at the adsorption position, and the flexible joint performs maintenance work at the working position. The electro-adsorption and robotic arm system includes an electro-adsorption system and a robotic arm system. The electro-adsorption system is equipped with an insulated electro-adsorption array, and the robotic arm system is a liquid metal flexible joint driven by electromagnetic force. Both are mounted on the robot body. The protection and monitoring system is used to monitor the operating status of the flexible joint in real time during maintenance work. The propulsion system is used to float and retrieve the flexible joint after maintenance work is completed.

[0044] In summary, this invention establishes an underwater electrically controlled adsorption force model by outputting a high-frequency square wave voltage to the electrode array that adsorbs the foot, confirming the first adsorption force. Through the Johnsen-Rahbek effect, a strong electric field is established between the electrode array and the adsorbed wall surface, confirming the second adsorption force. Adsorption is completed based on the first and second adsorption forces, enabling adsorption on concrete gates and steel plates covered with algae, thus improving the adsorption adaptability to different materials and environments. Furthermore, by introducing a first control current into the liquid metal flow channel of the robotic arm, the joint maintains a low-stiffness state according to the joint stiffness control formula, allowing it to enter narrow spaces to locate fault points. After locating the fault point, the input current of the liquid metal flow channel is instantly increased to the second control current, putting the robotic arm into a high-stiffness state. This, combined with the end effector, enables powerful operations. The joint can wrap around the trash rack like an octopus tentacle or squeeze into the narrow gaps of turbine blades, improving maintenance efficiency.

[0045] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0047] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for driving an underwater liquid metal flexible joint, characterized in that, include: S1. Collect underwater environmental parameters; S2. Based on environmental parameters, complete the modular configuration of the flexible joint; S3. After the flexible joint descends to the working depth, it completes the self-balancing of internal and external pressures and the positioning of the working surface, thus obtaining the working position and the adsorption position. S4. Activate the electro-controlled adsorption system in the flexible joint, adsorb at the adsorption position, and perform maintenance work on the flexible joint at the working position. S5. During the maintenance work, the operating status of the flexible joint is monitored in real time. S6. After the maintenance work is completed, the flexible joint is floated up and retrieved.

2. The underwater liquid metal flexible joint driving method according to claim 1, characterized in that: The environmental parameters include water depth, surface material, and work gap dimensions.

3. The underwater liquid metal flexible joint driving method according to claim 1, characterized in that: S2 includes: Based on the material of the working surface, an electrically controlled adsorption system is installed on the flexible joint chassis. The electrically controlled adsorption system includes several adsorption feet. Based on the water depth and the working gap size, a multi-degree-of-freedom liquid metal pressure-resistant flexible joint robotic arm is configured. Based on the water depth, the material of the working surface, and the size of the working gap, a protection and monitoring system is configured.

4. The underwater liquid metal flexible joint driving method according to claim 1, characterized in that: S3 includes: By utilizing the self-balancing structure of the flexible joint's internal and external pressures, the flexible joint can be matched with the underwater environment pressure in real time. The positioning system within the flexible joint first locates the adsorption position, and then locates the working position.

5. The underwater liquid metal flexible joint driving method according to claim 1, characterized in that: S4 includes: The adsorption power supply is activated, and a high-frequency square wave voltage is output to the electrode array adsorbing the foot to establish an underwater electronically controlled adsorption force model and confirm the first adsorption force. By utilizing the Johnsen-Rahbek effect, a strong electric field was established between the electrode array and the adsorbed wall surface, confirming the second adsorption force. Adjust the flexible joint posture, place the adsorbent foot close to the wall to be inspected, and complete the adsorption based on the first and second adsorption forces; A first control current is supplied to the liquid metal channel of the robotic arm. According to the joint stiffness control formula, the joint maintains a low stiffness state and enters a narrow space to locate the fault point. After locating the fault point, the input current of the liquid metal flow channel is instantly increased to the second control current, and the robotic arm is in a highly rigid state, which, together with the end effector, completes a powerful operation.

6. The underwater liquid metal flexible joint driving method according to claim 1, characterized in that: The formula for the underwater electronically controlled adsorption force model is as follows: in, The first adsorption force, The effective dielectric constant includes the effect of the water film. For the applied high-frequency square wave voltage, For equivalent dielectric thickness, The vacuum permittivity, The effective relative permittivity; The formula for calculating the equivalent dielectric thickness is as follows: in, The air gap is caused by the micro-roughness of the contact surface. The thickness of the insulating film. The effective dielectric constant of water, The relative permittivity of the insulating layer, This refers to the thickness of the residual water film.

7. The underwater liquid metal flexible joint driving method according to claim 6, characterized in that: The formula for calculating the second adsorption force is as follows: in, For the interface charge density, For contact resistance, For effective contact area, It is an enhancing factor.

8. The underwater liquid metal flexible joint driving method according to claim 4, characterized in that: The joint stiffness control formula is as follows: in, This refers to the bending stiffness of a flexible joint. This represents the initial stiffness of the elastomer substrate. The magnetic fluid pressure difference within the liquid metal flow channel. The current density in the fluid. The external magnetic field strength, The effective length of the flow channel. This is the stiffness proportionality coefficient.

9. The underwater liquid metal flexible joint driving method according to claim 1, characterized in that, S5 includes: The leakage current is detected in real time by a microampere-level current sensor in the electrode. When the detected leakage current exceeds the preset threshold, the high-frequency square wave voltage input of the faulty sub-region is automatically cut off. A negative potential relative to the ambient water is applied to the flexible joint chassis.

10. An underwater liquid metal flexible joint device, employing the underwater liquid metal flexible joint driving method described in claims 1-9, characterized in that, The system includes: The data acquisition system is used to collect underwater environmental parameters. A configuration system is used to perform modular configuration of flexible joints based on environmental parameters; The positioning system is used to achieve self-balancing of internal and external pressures and positioning of the working surface after the flexible joint descends to the working depth, thereby obtaining the working position and the adsorption position. An electro-controlled adsorption and robotic arm system is used to adsorb the flexible joint at the adsorption position, and the flexible joint performs maintenance operations at the working position. A protection and monitoring system is used to monitor the operating status of the flexible joint in real time during the maintenance work. A propulsion system is used to float and retrieve the flexible joint after the maintenance work is completed.

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