Control method of underwater separation robot considering wall rock terrain and undercurrent impact

Abstract

The application provides a control method of an underwater separation robot considering wall rock terrain and dark current impact, comprising the following steps: step one, the robot is dived to a parallel position with a rock wall task point, environment index evaluation is carried out, and an environment index is generated; step two, according to the environment index, the underwater separation robot continuously advances until the system displays a rated value of the environment index; step three, the underwater separation robot is separated into a diving machine body and an underwater rock climbing adsorption robot; step four, the underwater rock climbing adsorption robot is fixed and climbed through a suction cup tentacle, and a propeller at the tail of the underwater rock climbing adsorption robot provides additional advancing and anti-impact power for the underwater rock climbing adsorption robot, and when the water flow impact force reaches a dangerous threshold, the adsorption is kept in a standby state; step five, when the water flow impact force is lower than the dangerous threshold, the underwater rock climbing adsorption robot is pushed forward to climb. The method is aimed at the underwater separation robot, and a most suitable advancing path is planned and formed in combination with the wall rock terrain.

Description

Technical Field

[0001] This invention relates to the field of robot control, and more specifically to a control method for an underwater separation robot that takes into account rocky terrain and the impact of undercurrents. Background Technology

[0002] The complex and ever-changing marine environment makes the design of simple, agile, and highly adaptable underwater robots a key focus of robotics research. Scientists have proposed a new idea by combining bionics and robotics: underwater bionic robots. These robots are designed based on the shape, structure, and movement of marine organisms. Because marine life has evolved over millions of years, its biological models are highly adaptable to the marine environment, making it easier for underwater bionic robots to complete designated tasks. This allows people to better understand and utilize the ocean without disrupting its ecosystem. However, some seabed tasks are hampered by extremely complex, narrow seabed environments with strong currents, making it impossible for large underwater robots to perform their duties. Furthermore, the instability caused by currents makes it difficult to maintain a fixed position in the water simply by levitation, posing significant challenges to task execution.

[0003] When underwater robots need to enter the deep sea to perform rock wall operations, the complex and narrow terrain of the underwater rock walls, as well as the strong currents, necessitates reasonable process and path planning in order to complete the task and ensure that the structure of the underwater robot is not damaged. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a control method for an underwater separation robot that takes into account the terrain of the rock face and the impact of the undercurrent. For the underwater separation robot, the most suitable travel path is planned by taking into account the terrain of the rock face.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a control method for an underwater separation robot that takes into account the terrain of the rock face and the impact of the undercurrent, comprising the following steps:

[0006] Step 1: The underwater separation robot descends to a position parallel to the task point on the rock wall, conducts environmental index assessment, and generates an environmental index by combining the characteristics of the underwater rock wall and the flow velocity and direction of the water.

[0007] Step 2: Based on the environmental index, the underwater separation robot continues to advance until the system displays that the environmental index rating has been reached, at which point the underwater separation robot stops moving forward.

[0008] Step 3: After reaching the minimum distance that the underwater detachable robot can approach the mission point, the underwater detachable robot separates into the submersible body and the underwater climbing and adsorption robot. The submersible body floats in its original position and transmits data with the underwater climbing and adsorption robot, while the underwater climbing and adsorption robot is adsorbed onto the rock wall.

[0009] Step 4: The underwater climbing adsorption robot is fixed and climbs using its suction cup tentacles. At the same time, the propeller at the tail provides additional forward propulsion and impact resistance for the underwater climbing adsorption robot. The main control system calculates the combined impact resistance through suction cup adsorption and tail propeller. When the water flow impact force reaches the danger threshold, it automatically stops the tentacles from detaching from the rock wall and maintains the adsorption standby state.

[0010] Step 5: When the water flow impact force is below the danger threshold, the underwater climbing adsorption robot moves forward and climbs until it reaches the task point.

[0011] In the preferred embodiment, in step one, the underwater separation robot is equipped with sonar and radar current meter. The sonar detects the seabed ahead to obtain underwater rock wall characteristics, and the radar current meter comprehensively evaluates the water flow conditions in the waterway in real time to obtain the water flow velocity and direction. The environmental index is calculated as follows:

[0012]

[0013] G = a1·r + a2·s (2)

[0014] V = (V x V y V z (3)

[0015] θ=atan2(V y V x (4)

[0016]

[0017] In the formula: E is the environmental index, G is the underwater rock wall characteristic, V is the water flow velocity, and θ is the azimuth angle of the water flow direction. The angle of elevation represents the direction of water flow; w1, w2, w3, and w4 are weighting coefficients; r is the rock wall roughness; s is the rock wall stability; a1 and a2 are weighting coefficients; V x V y V z These represent the velocity components of the water flow in the x, y, and z axes, respectively.

[0018] In the preferred embodiment, the calculation method for the danger threshold in step four is as follows:

[0019]

[0020]

[0021]

[0022]

[0023] In the formula: T is the danger threshold. This is the maximum thrust of the propeller. Let be the maximum suction force of a single tentacle, x be the directional angle of the propeller (ranging from 0 to 2π), be the density of water, A1 be the effective area of ​​the propeller, and c be the density of water. d v is the drag coefficient. max Let η be the maximum velocity of the water flow propelled by the propeller, η be the propeller efficiency, and P be the maximum power of the propeller. out The water pressure outside the suction cup, p in A1 represents the pressure inside the suction cup, and A2 represents the effective contact area of ​​the suction cup.

[0024] In the preferred embodiment, in step five, when the water flow impact force is below the danger threshold, the underwater climbing adsorption robot maintains its diagonal tentacles in an adsorption state, partially detaches from the rock wall, and propels itself forward to climb. During the process, the water flow speed and direction are monitored in real time. Under the premise of minimizing the impact force on the underwater climbing adsorption robot, the shortest path is planned until the task point is reached.

[0025] In the preferred embodiment, an improved A* algorithm is used for path planning of the underwater climbing adsorption robot:

[0026] f(n)=α·L(n)+β·I(n)+H(n) (10)

[0027] I(n)=∑0.5ρ·A2·c d ·(|V|·cosγ) 2 (11)

[0028]

[0029] w(n)=ρ·A2·V·Δv (13)

[0030] In the formula: f(n) is the total cost of the path, L(n) is the actual cost from the starting point to the current point, I(n) is the cumulative value of the water flow impact force, H(n) is the estimated cost from the current point to the task point considering the water flow velocity and direction, and α and β are weighting coefficients;

[0031] A2 is the effective area of ​​the robot impacted by the water flow, ρ is the density of water, V is the velocity of the water flow, and γ is the angle between the direction of the water flow and the forward direction of the underwater climbing adsorption robot (m). xm y (n) represents the coordinates of the target point m. x n y ) represents the coordinates of the current node; w(n) represents the water flow impact force of the current node n; Δv represents the change in water flow velocity per unit time; and k represents the weighting coefficient.

[0032] The present invention provides a control method for an underwater separation robot that takes into account the terrain of rock walls and the impact of undercurrents, which has the following beneficial effects:

[0033] 1. The underwater robot can be separated into a submersible body and an underwater climbing and adsorption robot through a detachable structure. The underwater climbing and adsorption robot can be propelled by suction cups and a 360° propeller at the tail to be able to move higher and lower than the impact of water flow. It can also plan the most suitable path based on the terrain of the rock wall, which greatly facilitates the execution of specific underwater tasks.

[0034] 2. After assessing the environment, the underwater robot can perceive environmental characteristics in advance, enabling the robot system to make correct control decisions, perform tasks more safely and reliably in complex environments, avoid task failure due to environmental factors, and improve the system's environmental adaptability and stability.

[0035] 3. Achieve seamless integration of environmental perception and system control, i.e., environmental index feedback control. This enables the underwater robot to adjust its speed reasonably according to environmental conditions, realizing adaptive control for stopping / running, and effectively improving the system's adaptability and robustness in complex environments.

[0036] 3. After the underwater split-type robot reaches the minimum distance from the overall target point, it separates into the submersible body and the underwater climbing robot. The underwater climbing robot has a smaller body, which allows it to enter narrow environments to operate, improving the flexibility of operation and further enhancing the system's environmental adaptability.

[0037] 4. The underwater climbing robot's tentacle suction cups provide reliable adhesion, while the propellers provide additional propulsion power. Together, they enhance the stability of the crawling process. The main control system monitors the impact force in real time and actively detaches and hovers when the maximum load capacity is reached, achieving adaptive safety control and improving the stability and safety of the underwater robot during operation.

[0038] 5. The underwater climbing robot adaptively adjusts its propulsion speed based on real-time monitoring of impact force, achieving closed-loop control that adapts to the environment and improves the efficiency of task completion while ensuring safety. Attached Figure Description

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0040] Figure 1This is the control flowchart for the method;

[0041] Figure 2 A diagram showing the underwater robot's movement across the seabed;

[0042] Figure 3 A schematic diagram of the attachment of an underwater climbing adhesive robot;

[0043] Figure 4 This is an enlarged schematic diagram of the propeller;

[0044] Figure 5 This is a path planning diagram for the rock-climbing adhesive robot in the embodiment;

[0045] In the picture: 1. Submersible body, 2. Underwater climbing and adsorption robot, 3. Suction cup tentacles, 4. Propeller, 5. Rock wall. Detailed Implementation

[0046] Combination Figures 1-5 The control method for an underwater separation robot that takes into account the topography of rock walls and the impact of undercurrents is described below.

[0047] A control method for an underwater separation robot that takes into account rock face topography and undercurrent impact includes the following steps:

[0048] Step 1: The underwater separation robot descends to a position parallel to the task point on the rock wall, conducts environmental index assessment, and generates an environmental index by combining the characteristics of the underwater rock wall and the flow velocity and direction of the water.

[0049] like Figures 2-4 As shown, the underwater separation robot includes a submersible body and an underwater climbing and adsorption robot. The submersible body and the underwater climbing and adsorption robot are structurally interlocked. In practice, the submersible body and the underwater climbing and adsorption robot can be connected by electromagnets and separated by power failure.

[0050] The submersible is equipped with a multi-functional depth sounder and a communication module. The multi-functional depth sounder integrates acoustic and optical modules to measure the distance between the robot and the seabed and targets. The communication module is used for wireless communication between the submersible and the underwater climbing robot.

[0051] The underwater climbing adhesive robot includes suction cup tentacles and a 360° propeller. The suction cup tentacles are used to attach the underwater climbing robot to the rock wall for climbing, providing attachment support; the 360° propeller provides additional propulsion for climbing and provides impact resistance against underwater currents.

[0052] After the underwater climbing suction robot separates from the submersible body, a 360° rotating propeller at the tail propels it quickly onto the rock face. Then, six tentacles equipped with suction cups firmly attach to the rock and begin moving towards the target point. During this attachment and movement, the propeller remains operational, adjusting its direction according to the water flow to minimize the impact of underwater currents on the climbing robot.

[0053] The environmental index is composed of underwater rock wall features and water flow velocity and direction. The underwater rock wall features are obtained by the underwater detachable robot through sonar detection, forming a comprehensive assessment index of the seabed ahead. The water flow velocity and direction are detected by the radar current meter on the fuselage, which provides a comprehensive assessment of the water flow conditions in the waters along the route in real time.

[0054] The environmental index is calculated as follows:

[0055]

[0056] G=a1·r+d2·s (2)

[0057] V = (V x V y V z (3)

[0058] θ=atan2(V y V x (4)

[0059]

[0060] In the formula: E is the environmental index, G is the underwater rock wall characteristic, V is the water flow velocity, and θ is the azimuth angle of the water flow direction. The angle of elevation represents the direction of water flow; w1, w2, w3, and w4 are weighting coefficients; r is the rock wall roughness; s is the rock wall stability; a1 and a2 are weighting coefficients; V x V y V z These represent the velocity components of the water flow in the x, y, and z axes, respectively.

[0061] Step 2: Based on the environmental index, the underwater separation robot continues to advance until the system displays that the environmental index rating has been reached, at which point the underwater separation robot stops moving forward.

[0062] The environmental index rating is a key indicator for whether an underwater detachable robot can continue to move forward. As the underwater detachable robot continues to advance towards the mission target point, the environment becomes narrower and the undercurrents become stronger, and its environmental index continues to rise, indicating that the environment is gradually deteriorating. When the environmental index calculated by the system reaches the environmental index rating, the underwater detachable robot may endanger its own safety if it continues to move forward.

[0063] Step 3: After reaching the minimum distance from which the underwater detachable robot can approach the mission point, the underwater detachable robot separates into the submersible body and the underwater climbing and adsorption robot. The submersible body floats in its original position and transmits data with the underwater climbing and adsorption robot, while the underwater climbing and adsorption robot adheres to the rock wall.

[0064] During the adsorption process, the propeller remains operational, adjusting its propulsion direction according to the water flow to minimize the impact of underwater currents on the climbing robot.

[0065] Step 4: The underwater climbing adsorption robot is secured and climbs using its suction cup tentacles, while the propeller at the tail provides additional forward propulsion and impact resistance.

[0066] The main control system calculates the combined impact resistance of the suction cups and the tail propeller. When the water flow impact force reaches the danger threshold, it automatically stops the tentacles from detaching from the rock wall and maintains the suction standby state.

[0067] The method for calculating the danger threshold is as follows:

[0068]

[0069]

[0070]

[0071]

[0072] In the formula: T is the danger threshold. This is the maximum thrust of the propeller. Let be the maximum suction force of a single tentacle, x be the directional angle of the propeller (range [0, 2π]), ρ be the density of water, A1 be the effective area of ​​the propeller, and c be the maximum suction force of a single tentacle. d v is the drag coefficient. max Let η be the maximum velocity of the water flow propelled by the propeller, η be the propeller efficiency, and P be the maximum power of the propeller. out The water pressure outside the suction cup, p in A1 represents the pressure inside the suction cup, and A2 represents the effective contact area of ​​the suction cup.

[0073] Step 5: When the water flow impact force is below the danger threshold, the underwater climbing adsorption robot maintains its diagonal tentacles in an adsorbed state, partially detaches from the rock face, and propels itself forward to climb. During the process, the robot uses the lidar on its body to detect the rock face environment, and plans the most suitable climbing path while ensuring that the impact force on the underwater climbing adsorption robot is minimized, based on the combined water flow impact index and terrain ruggedness index, until it reaches the task point.

[0074] An improved A* algorithm is used for path planning of an underwater climbing adhesive robot:

[0075] f(n)=α·L(n)+β·I(n)+H(n) (10)

[0076] I(n)=∑0.5ρ·A2·c d ·(|V|·cosγ) 2 (11)

[0077]

[0078] w(n)=ρ·A2·V·Δv (13)

[0079] In the formula: f(n) is the total cost of the path, L(n) is the actual cost from the starting point to the current point, I(n) is the cumulative value of the water flow impact force, H(n) is the estimated cost from the current point to the task point considering the water flow velocity and direction, and α and β are weighting coefficients;

[0080] A2 is the effective area of ​​the robot impacted by the water flow, ρ is the density of water, V is the velocity of the water flow, and γ is the angle between the direction of the water flow and the forward direction of the underwater climbing adsorption robot (m). x m y (n) represents the coordinates of the target point m. x n y ) represents the coordinates of the current node; w(n) represents the water flow impact force of the current node n; Δv represents the change in water flow velocity per unit time; and k represents the weighting coefficient.

[0081] To verify the feasibility of this method, a specific scenario is set up in this example:

[0082] In this embodiment, the environmental indicator parameters are shown in Table 1:

[0083] Table 1 Environmental Indicator Parameters

[0084]

[0085]

[0086] According to equation (2), the underwater rock wall characteristic G = 0.7 can be calculated;

[0087] According to equation (3), the magnitude of the water flow velocity |V| = 2.29 can be calculated;

[0088] According to equations (4) and (5), the azimuth and elevation angles of the water flow direction can be calculated as θ = 26.57°.

[0089] Finally, substituting all these parameters into equation (1) for calculation, we obtain the environmental index E = 10.33 in this example.

[0090] Therefore, when the system displays that the environmental index rating of 10.33 has been reached, the underwater separation robot stops moving forward, and when the robot as a whole can approach the minimum distance to the mission point, the underwater separation robot separates into the submersible body and the underwater climbing adsorption robot.

[0091] In this example, the danger threshold parameters are shown in Table 2:

[0092] Table 2 Hazard threshold parameters

[0093] parameter symbol numerical values density of water ρ 1000kg / m^3 propeller area <![CDATA[A1]]> 0.1m^2 drag coefficient <![CDATA[c d ]]> 0.8 propeller efficiency η 0.6 propeller power P 1000W External water pressure <![CDATA[p out ]]> 105Pa Internal pressure <![CDATA[p in ]]> 104Pa suction cup area <![CDATA[A2]]> 0.01m^2 Direction angle x 30°

[0094] The maximum thrust of the propeller can be calculated according to equation (7).

[0095] The maximum velocity v of the propeller propelling the water flow can be calculated according to equation (8). max =0.848m / s;

[0096] The maximum suction force of a single tentacle can be calculated according to equation (9).

[0097] Finally, substituting all these parameters into equation (6) for calculation, we can obtain the danger threshold T = 108.6N in this example.

[0098] Therefore, when the water flow impact force reaches the danger threshold of 108.6N, the system will automatically stop the tentacles from detaching from the rock wall, maintain an adsorption standby state, and wait for the water flow impact force to drop below the danger threshold before continuing to move forward.

[0099] The main principle of the traditional A* algorithm is as follows: take the starting point as the initial node, search the 8 neighborhoods next to the initial node, and select the node with the minimum cost after evaluation by the heuristic function. Then search the 8 neighborhoods of this node, select the next node with the minimum cost, and repeat the above steps until the selected node coincides with the target point. Finally, connect these nodes with the minimum cost to obtain an optimal path.

[0100] like Figure 5As shown, compared with the traditional A* algorithm, this method fully considers the influence of environmental fluid on path selection. When calculating the cost, it adds the estimated cost from the current point to the task point, taking into account the flow velocity and direction of the water flow. It also performs vector synthesis of the water flow forces in different directions, taking into account the combined influence of flow velocity and direction, resulting in a more accurate evaluation.

[0101] Therefore, this method not only leverages the advantages of the A* algorithm itself, but also incorporates real-world environmental factors, thereby improving the accuracy and environmental adaptability of path planning.

Claims

1. A control method for an underwater separation robot considering rocky terrain and undercurrent impact, characterized in that, Includes the following steps: Step 1: The underwater detachable robot descends to a position parallel to the task point on the rock wall and conducts an environmental index assessment. This assessment combines underwater rock wall characteristics with water flow velocity and direction to generate an environmental index. The underwater detachable robot is equipped with sonar and a radar current meter. The sonar detects the seabed ahead, obtaining underwater rock wall characteristics. The radar current meter provides a real-time comprehensive assessment of the water flow conditions along the route, obtaining water flow velocity and direction. The environmental index is calculated as follows: (1)； (2)； (3)； (4)； (5)； In the formula: E G represents the environmental index, and G represents the underwater rock wall characteristics. V For water flow velocity, The azimuth of the water flow direction. The angle of elevation of the water flow. w 1 、w 2 、w 3 、w 4 represents the weighting coefficient. r For rock wall roughness, s For rock wall stability; a 1 、a 2. Weighting coefficients V x 、V y 、V z The water flow is respectively in x axis, y axis, z Velocity component along the axial direction; Step 2: Based on the environmental index, the underwater separation robot continues to advance until the system displays that the environmental index rating has been reached, at which point the underwater separation robot stops moving forward. Step 3: After reaching the minimum distance that the underwater detachable robot can approach the mission point, the underwater detachable robot separates into the submersible body and the underwater climbing and adsorption robot. The submersible body floats in its original position and transmits data with the underwater climbing and adsorption robot, while the underwater climbing and adsorption robot is adsorbed onto the rock wall. Step 4: The underwater climbing adsorption robot is fixed and climbs using its suction cup tentacles. At the same time, the propeller at the tail provides additional forward propulsion and impact resistance for the underwater climbing adsorption robot. The main control system calculates the combined impact resistance through suction cup adsorption and tail propeller. When the water flow impact force reaches the danger threshold, it automatically stops the tentacles from detaching from the rock wall and maintains the adsorption standby state. Step 5: When the water flow impact force is below the danger threshold, the underwater climbing adsorption robot moves forward and climbs until it reaches the task point.

2. The control method for an underwater separation robot considering rock face topography and undercurrent impact as described in claim 1, characterized in that, In step four, the danger threshold is calculated as follows: (6)； (7)； (8)； (9)； In the formula: T This is the danger threshold. This is the maximum thrust of the propeller. This represents the maximum suction force of a single tentacle. x The directional angle of the propeller, with a value range of [value missing]. , The density of water, A 1 represents the effective area of ​​the propeller. c d The drag coefficient, v max The maximum speed at which the propeller propels the water flow. For the efficiency of the propeller, P This is the maximum power of the propeller. p out The water pressure outside the suction cup, p in For the pressure inside the suction cup, A 2 represents the effective contact area of ​​the suction cup.

3. The control method for an underwater separation robot considering rock face topography and undercurrent impact according to claim 1, characterized in that, In step five, when the water flow impact force is below the danger threshold, the underwater climbing adsorption robot maintains its adsorption state with its diagonal tentacles, partially detaches from the rock wall, and moves forward to climb. During the process, the water flow speed and direction are monitored in real time. Under the premise of minimizing the impact force on the underwater climbing adsorption robot, the shortest path is planned until the task point is reached.

4. The control method for an underwater separation robot considering rock face topography and undercurrent impact according to claim 3, characterized in that, Adopting improved A The algorithm performs path planning for an underwater climbing adhesive robot: (10)； (11)； (12)； (13)； In the formula: f ( n ) represents the total cost of the path. L ( n () represents the actual cost from the starting point to the current point. I ( n This represents the cumulative value of the water flow impact force. H ( n To estimate the cost from the current point to the task point, taking into account the water flow velocity and direction. These are the weighting coefficients; A 2 represents the effective area of ​​the robot impacted by the water flow. The density of water, V The speed of the water flow, The angle between the direction of water flow and the direction of movement of the underwater climbing adsorption robot. For target point m coordinates The coordinates of the current node; w ( n ) is the current node n The impact force of the water flow, It is the change in water flow velocity per unit time. k These are the weighting coefficients.

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