A diversion tunnel robot original route return guiding system

Abstract

This invention discloses a return-to-base guidance system for a water diversion tunnel robot, comprising: an umbilical cable, an underwater electrode, an electrode discharge driver, and at least one underwater electromagnetic detector. The electrode discharge driver is located on land and connected to the umbilical cable and the underwater electrode. The underwater electrode is located at the initial end of the water diversion tunnel and is underwater. The underwater electromagnetic detector is located on the robot. This invention uses a cable electrode formed by the cross-section of the umbilical cable to form an underwater discharge circuit with the cable electrode, the underwater electrode, and the water medium. The electrode discharge driver loads a current pulse signal into this discharge circuit, and the ring-shaped distributed electromagnetic field signal formed by the current pulse signal guides the inspection robot to return along the original route. This achieves low-cost, simple, and reliable ROV return, unaffected by underwater visibility, while reducing ROV power battery consumption and ensuring ROV return energy supply.

Description

Technical Field

[0001] This invention relates to the field of robot malfunction return technology, specifically to a water diversion tunnel robot return-to-origin guidance system. Background Technology

[0002] After years of operation, the water diversion tunnels of hydropower stations are subject to various hazards, such as biological adhesion to the tunnel walls and deformation caused by water flow and fine sand erosion. These hazards can lead to damage and blockage of the water diversion tunnels. Regular inspections and detection of the water diversion tunnels are necessary to identify potential hazards and take timely measures to eliminate them.

[0003] Currently, in China, robots with hovering capabilities (hereinafter referred to as ROVs or patrol robots) are equipped with acoustic and optical detectors on their bow and five other end faces (up, down, left, and right) to patrol, detect, and observe the walls of the water diversion tunnel along a predetermined route. The ROV is powered and controlled by an umbilical cable at the external trunk end of the water diversion tunnel. This umbilical cable is over 3000m long and is typically made of polyether-type polyurethane sheathed cable, designed with zero buoyancy (or slightly positive buoyancy) to prevent coiling or tangling. Because the water diversion tunnel is relatively long and may have bends, ascents, descents, or branching passages, the ROV utilizes the acoustic and optical detectors on its five end faces to acquire distance data and optical observation images between the ROV and the tunnel walls. The acoustic and optical detectors on the bow can promptly detect obstacles in the channel ahead, allowing for precise control of the ROV's navigation and patrol observation along the water diversion tunnel.

[0004] During ROV patrols of water intake tunnels, unexpected situations may arise, such as entanglement of the ROV's umbilical cable due to protruding structures, attached organisms, or aquatic plants on the tunnel walls. This could prevent the ROV from escaping, resulting in a loss of control for both forward and backward movement. In such cases, the ROV needs to cut the umbilical cable and use its onboard battery to navigate back along the original route to the initial starting point, thus rescuing itself from the predicament. Current self-rescue methods primarily involve sending underwater sound waves from the initial starting point. The beacon hydrophone on the ROV detects the direction of the sound signal and guides the ROV back along the original route. However, sound waves are reflected multiple times by the tunnel walls, causing rapid attenuation and changes in direction. Beyond 1 km (or even shorter distances), effective detection and identification of sound waves become increasingly difficult, posing significant challenges to ROV return navigation. Furthermore, the ROV needs to use its internally preset route to determine the return path and uses the acoustic and optical detection results to control the robot's return journey. This process consumes considerable battery power, and over long distances, the ROV may experience insufficient power. Summary of the Invention

[0005] To address the aforementioned issues, the inventors have provided a return-to-base guidance system for a water diversion tunnel robot, which effectively solves the problem of accurate return-to-base guidance for a water diversion tunnel inspection robot after a remote control cable failure.

[0006] This invention provides a return-to-origin guidance system for a water diversion tunnel robot, comprising:

[0007] Umbilical cable; connection to the robot;

[0008] The underwater electrode is located at the initial end of the water diversion tunnel and is underwater; after the umbilical cable is cut, its cross-section forms a cable electrode, and the cable electrode and the underwater electrode form a closed electrical circuit through the water medium;

[0009] An electrode discharge driver, located on land and connected to the umbilical cable and underwater electrode, is used to apply a current pulse signal to the cable electrode and underwater electrode in a closed electrical circuit, so that the severed umbilical cable generates a guiding signal.

[0010] At least one underwater electromagnetic detector, mounted on the robot, is used to detect guidance signals on the umbilical cable, with its detection direction perpendicular to the umbilical cable routing direction.

[0011] Furthermore, the underwater electrode is a copper plate, copper rod, or zinc-copper mesh, with an area greater than 100 cm². 2 .

[0012] Furthermore, the underwater electrode is located at a depth of not less than 1m.

[0013] Working principle of the invention:

[0014] When the ROV encounters a blockage or cable entanglement within the water diversion tunnel and is unable to break free, it cuts the umbilical cable. The cross-section of one or more core wires within the cable forms a cable electrode. The cable electrode has a smaller conductive cross-section and serves as the negative electrode, while the underwater electrode at the initial end of the water diversion tunnel has a larger area and serves as the positive electrode. The cable electrode, the underwater electrode, and the water medium form an electrical circuit. The electrode discharge driver applies a pulse current signal to this electrical circuit, generating a pulsed circular electromagnetic wave field along the umbilical cable. The underwater electromagnetic detector on the ROV detects the electromagnetic pulse signal of this circular electromagnetic wave field and uses it as a navigation guidance signal for the ROV. The ROV control system then controls the ROV to return along this signal.

[0015] Using the electrodes as positive and negative electrodes, the two electrodes form a discharge circuit in the water medium. A current pulse signal is loaded into the umbilical cable, and the ring-shaped distributed electromagnetic field signal formed by the current pulse signal guides the inspection robot to return along the original route.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) The water diversion tunnel robot return navigation guidance system provided by the present invention has low implementation cost, simple and reliable operation, and can accurately guide the ROV to return along the original route regardless of underwater visibility.

[0018] (2) When returning to the ROV, there is no need to use high-power equipment such as supplementary lights and cameras, which reduces the consumption of ROV power batteries and ensures the energy supply for ROV return. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the original route return guidance system for the water diversion tunnel robot in Example 1.

[0020] Figure 2 This is a schematic diagram of the original route return guidance system for the water diversion tunnel robot in Example 1.

[0021] Figure label:

[0022] 1-Initial end of water diversion tunnel; 2-Electrode discharge actuator; 3-Umbilical cable; 31-Cable electrode; 4-Underwater electrode; 5-ROV; 51-Underwater electromagnetic detector; Detailed Implementation

[0023] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Example

[0024] like Figure 1 As shown, this invention provides a return-to-origin guidance system for a water diversion tunnel robot, comprising: an underwater electrode 4, an umbilical cable 3, an electrode discharge actuator 2, an underwater electromagnetic detector 51, and a sonar obstacle avoidance system. The electrode discharge actuator 2 is located on the shore at the initial end 1 of the water diversion tunnel. The underwater electrode 4 is a copper plate or copper rod electrode with a relatively large area (e.g., 100 cm²). 2 Located below the water surface at the initial end 1 of the water diversion tunnel, at a depth greater than 1m. Electrode discharge actuator 2 is connected to underwater electrode 4 and umbilical cable 3 respectively. After the end of umbilical cable 3 connected to ROV5 is cut, a core wire with a larger cross-sectional area or a combination of core wires is selected as cable electrode 31. After umbilical cable 3 is cut, the electrical circuit formed by cable electrode 31, underwater electrode 4, and the water medium discharges. Underwater electrode 4, with its larger area, acts as the positive electrode, losing electrons and corroding, while cable electrode 31, with its smaller conductive cross-section, acts as the negative electrode, which can appropriately extend the electrode's working life.

[0025] The electrode discharge driver 2 is used to apply a current pulse signal to the electrical circuit. The applied current is greater than 0.5A. The current pulse working period can be selected as 3s or longer. The current pulse time width is 50ms and the working frequency is 300Hz, ensuring that there are more than 15 cycles of signal within the pulse width, which is beneficial for signal detection.

[0026] The underwater electromagnetic detector 51 is a fluxgate magnetometer with low sensitivity requirements (e.g., 20 nT). Since the cable has zero or positive buoyancy, it may be on the surface of the water in the intake tunnel. The underwater electromagnetic detector 51 can be installed on the upper or stern of the ROV5. Because the ROV is relatively close to the cable during navigation and the direction of the magnetic field lines is known, the underwater electromagnetic detector 51 can be a single-axis (or tri-axis) type, with the detection direction perpendicular to the umbilical cable route 3 (i.e., perpendicular to the direction of the intake tunnel). Preferably, two underwater electromagnetic detectors 51 are used, installed at the front and rear of the ROV5 respectively. This helps determine the ROV5's navigation direction and reduces the loss of range during "S"-shaped voyages.

[0027] The sonar obstacle avoidance system uses a conventional obstacle avoidance system, mainly used for obstacle avoidance during ROV operation. To reduce the impact of turbid water on image sonar detection, the operating frequency of the image sonar can be selected to be 450kHz or lower.

[0028] Specifically, when ROV5 malfunctions and needs to return, it cuts the umbilical cable 3, exposing the cable electrode 31 and forming an electrical circuit with the underwater electrode 4 and the water medium. Simultaneously, the electrode discharge driver 2 at the shore end applies a pulse current I to the umbilical cable 3, generating a ring-shaped pulsed electromagnetic wave field around the umbilical cable 3. The magnetic field strength distribution of this pulsed electromagnetic wave field is such that the magnetic field lines are perpendicular to the core wire direction of the umbilical cable 3 and inversely proportional to the distance from the umbilical cable 3. The underwater electromagnetic detector 51 detects this ring-shaped distributed electromagnetic field signal and guides the ROV to return along its original route. The forward, vertical, and lateral image sonar of ROV5 operates to acquire obstacle avoidance signals, which are transmitted to the ROV control system. The ROV control system then controls the ROV to navigate in the middle of the water intake tunnel to avoid collisions with the tunnel walls.

[0029] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A return-to-origin guidance system for a water diversion tunnel robot, comprising: The umbilical cable connected to the robot is characterized by further comprising: The underwater electrode is located at the initial end of the water diversion tunnel and is underwater; after the umbilical cable is cut, its cross-section forms a cable electrode, and the cable electrode and the underwater electrode form a closed electrical circuit through the water medium; An electrode discharge driver, located on land and connected to the umbilical cable and underwater electrode, is used to load a current pulse signal into a closed electrical circuit, causing the severed umbilical cable to generate a guiding signal. At least one underwater electromagnetic detector, mounted on the robot, is used to detect guidance signals on the umbilical cable, with its detection direction perpendicular to the umbilical cable routing direction.

2. The penstock robot return journey guiding system according to claim 1, wherein The underwater electrode is a copper plate, copper rod, or zinc-copper mesh.

3. The penstock robot return journey guiding system according to claim 2, wherein The underwater electrode is a copper plate, a copper rod or a zinc-copper mesh with an area not less than 100 cm 2 .

4. The tunnel robot homeward guidance system according to any one of claims 1 to 3, wherein The underwater electrode is located at a depth of not less than 1m.

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