An amphibious vehicle underwater path planning method based on energy loss optimization

Abstract

The present application belongs to the technical field of autonomous path planning of amphibious vehicles, and particularly relates to an underwater path planning method for amphibious vehicles based on optimal energy loss, which comprises the following steps: constructing a three-dimensional grid map, integrating seabed terrain, ocean current direction and obstacle information to form a terrain-ocean current composite map; applying a particle swarm algorithm to generate a series of control points between the starting point and the ending point to ensure that the path maintains a safe height from the seabed; calculating the terrain slope, yaw angle and interaction force between the vehicle and the ground and the ocean current for each path step, and quantifying the ground resistance and ocean current resistance; evaluating the energy loss of each step based on the resistance and travel distance, and accumulating the total loss; and finally selecting the optimal path with the minimum energy loss by iteratively optimizing the path based on the collision detection and the minimum energy loss criterion. The present application realizes energy-efficient underwater path planning by comprehensively considering the terrain, ocean current and vehicle characteristics, and improves the endurance and driving safety of amphibious vehicles.

Description

Technical Field

[0001] This invention belongs to the field of autonomous path planning technology for amphibious vehicles, specifically relating to an underwater path planning method for amphibious vehicles based on optimal energy loss. Specifically, it is a path planning method that comprehensively considers ocean current resistance and land resistance to achieve optimal global energy loss in complex water-land transition environments. Background Technology

[0002] Amphibious vehicles, as specialized platforms capable of operating alternately in land and underwater environments, have broad application prospects in fields such as resource exploration, environmental monitoring, military reconnaissance, and emergency rescue. When performing underwater missions, their energy supply typically relies entirely on their own limited batteries, and their endurance and operational time are directly constrained by energy consumption. Therefore, achieving optimal energy management during underwater navigation is crucial for extending mission duration and improving mission success rates.

[0003] Existing path planning techniques, whether for underwater vehicles or terrestrial robots, typically treat the environment as homogeneous or of a single type, focusing their optimization objectives primarily on finding the shortest path or the shortest time. For underwater vehicles, current research has begun to consider the influence of ocean currents, attempting to save energy by treating the vehicle as a point mass and seeking a "downstream" path within the flow field. However, such methods have significant limitations: they are generally based on simplified hydrodynamic models, failing to accurately characterize the unique shape of the vehicle, its navigation attitude, and the ocean current resistance generated by their interaction with the ocean currents, leading to significant discrepancies between energy consumption estimates and actual values.

[0004] On the other hand, while path planning for ground vehicles has considered the differences in ground resistance caused by different surface properties (such as soft sand, muddy swamps, and hard surfaces), its models are entirely based on ground mechanics and cannot describe the buoyancy and fluid pressure drag experienced by vehicles in water. When planning paths transitioning from water to land, existing technologies reveal a fundamental flaw: they cannot coordinately optimize the work done by vehicles underwater to overcome ocean current resistance and the work done on land to overcome ground resistance within a unified physical framework.

[0005] Therefore, there is an urgent need in this field for a novel path planning method that can overcome the barriers between aquatic and terrestrial environments and establish a unified energy loss assessment model. This method must be able to deeply integrate the accurate calculation of ocean current resistance and land resistance, and seek optimization at the global level to generate truly energy-efficient through paths, thereby overcoming the problems of insufficient consideration of environmental heterogeneity and one-sided optimization objectives in existing technologies. Summary of the Invention

[0006] (a) Technical problems to be solved The technical problem to be solved by this invention is: how to provide an underwater path planning method for amphibious vehicles with optimal energy loss.

[0007] (II) Technical Solution To address the aforementioned technical problems, this invention provides an underwater path planning method for amphibious vehicles based on optimal energy loss, such as... Figure 1 As shown, the underwater path planning method for amphibious vehicles includes the following steps: Step S1: Underwater map construction; Step S2: Perform route planning; Step S3: Load terrain slope information; Step S4: Load vehicle-ground characteristics; Step S5: Load vehicle-ocean current characteristics; Step S6: Energy loss assessment; Step S7: Determine if a collision has occurred; Step S8: Determine if the path is optimal.

[0008] In step S1, underwater map construction includes: Based on the scope of the target sea area, plan the map size and initialize a three-dimensional spatial grid map. The map structure size is represented as length × width × height. Plan a sea area grid map of a certain length, width and depth for amphibious vehicle underwater path planning. That is, plan a water area space with a grid map length of 200 meters, a width of 200 meters and a water depth of 15 meters, i.e., a 200×200×15 sea area for amphibious vehicle underwater path planning. Among them, based on the pre-detected seabed topographic data (such as multibeam bathymetry data), the row vector of the matrix is ​​the length of the target sea area (200 meters), the column vector is the width of the mapped target sea area (200 meters), and the values ​​in the matrix are the elevations of the topography. Among them, the ocean current direction is set according to the wind direction of the target sea area detected in the preliminary detection, and the indication point is set in the 200×200×15 sea area. The indication point is indicated by the arrow to show the ocean current direction. Among them, obstacles are set according to the pre-detected seabed topographic obstacle information and suspected non-communication areas. The obstacles are not limited to the shape. In this embodiment, they are represented by a sphere. This involves loading digital seabed topography data, ocean current direction data, and obstacle distribution information based on the previously detected target sea area topography and wind speed, and overlaying these onto a regional raster map to form a topography-ocean current composite map, such as... Figure 4 As shown.

[0009] In step S2, path planning is performed: Based on the topographic-ocean current composite map, the Particle Swarm Optimization (PSO) algorithm is applied for global underwater path planning (path planning methods such as A-Star, RRT, and PSO intelligent algorithm can all be used to achieve this). The starting and ending points of the tasks performed by the amphibious vehicle are set according to actual needs. In this embodiment, (1, 1) in the topographic-ocean current composite map is set as the starting point and (200, 200) is set as the ending point. The number of calculation iterations is set to 200, and the number of iterations can be adjusted according to the map size and calculation efficiency. The PSO (Particle Swarm Optimization) algorithm is applied for underwater path planning of amphibious vehicles. Based on the accuracy requirements of path planning, a series of control points are generated between the starting point and the ending point. In this embodiment, the number of control points is set to 10. The terrain interpolation function forces the control point to remain at a safe height, ensuring that the amphibious vehicle's path remains in close contact with the terrain and does not collide with the seabed. The safe height is consistent with the vehicle's center of gravity height. If the vehicle's center of gravity height cannot be accurately obtained, it is simplified to half of the vehicle's height.

[0010] In step S3, terrain slope information is loaded: Planning each path requires deriving the 3D coordinates of the control points, as shown below: In the formula, n To control the number of points, in this embodiment... n =10; Two adjacent control points are defined as a step size. The yaw and slope information for each step size are calculated as follows: In the formula: , For the first j Yaw angle and slope angle of one step length.

[0011] In step S4, the vehicle-ground characteristics are loaded: Based on the seabed soil type information of the target sea area, the mechanical property parameters of the soil are loaded. Combined with the weight, structure and size information of the amphibious vehicle, the vehicle-ground interaction characteristics are quantified, and the ground resistance of the amphibious vehicle underwater travel is calculated.

[0012] In step S5, the vehicle-ocean current characteristics are loaded: Based on the hydrological information of the target sea area, the mechanical properties of the underwater ocean current are loaded, and combined with the shape, structure and size information of the amphibious vehicle, the interaction characteristics between the vehicle and the ocean current are quantified, and the ocean current resistance of the amphibious vehicle underwater is calculated.

[0013] In step S6, energy loss assessment is performed. Based on the ground resistance, ocean current resistance, and travel distance of the amphibious vehicle underwater, the energy loss between each pair of adjacent control points is calculated, and then the energy loss of the entire path is calculated by summing the results, expressed as: In the formula, For the first j Energy loss per step length along the path; For the first j Vehicle ground resistance per step length; For the first j The vehicle's resistance to ocean currents is measured in steps. No. j The path distance of each step is expressed as: The total energy loss for the entire path is calculated by summing the energy loss at each step, and expressed as follows: .

[0014] In step S7, it is determined whether a collision has occurred: Check if the currently planned path collides with an obstacle. If no collision is found, proceed to the next step; if a collision is found, replan the path. In step S8, it is determined whether the path is optimal: The criterion for determining the optimal path is to minimize the energy loss during the planning from the starting point to the ending point. After the particle swarm optimization algorithm completes its loop, the amphibious vehicle selects the optimal path to execute. Figure 5 As shown.

[0015] Among them, such as Figure 2 As shown, the loading of vehicle-ground characteristics in step S4 specifically includes the following steps S41-S43: Step S41: Ground mechanical property assessment: Based on the pre-surveyed seabed soil conditions, the bearing capacity of the ground is quantified using the basic mechanical properties of the soil, expressed as: In the formula: z j For amphibious vehicles to travel j The amount of seabed subsidence per step; The underwater grounding pressure of the vehicle; , For cohesion and friction modulus; b Track width; n The subsidence index is used; in this embodiment, the seabed surface is sandy, and its cohesion, friction, and subsidence indices are 3.4e-2. 0.8e-3 0.55 and above are calibrated according to the test results of seabed soil characteristics; Step S42: Calculation of vehicle bulldozing resistance: The seabed is soft soil, resulting in significant bulldozing resistance for amphibious tracked vehicles. The longitudinal ground resistance is expressed as: In the formula: For longitudinal soil resistance of tracked vehicles; ρ The density of seabed sand is taken as 2.0 g / cm³. The internal friction angle of the soil is taken as 28°. Step S43: Calculation of vehicle ground resistance: When an amphibious vehicle travels on a slope, the vehicle's underwater weight will generate additional drag, which is represented as: In the formula: Adds travel resistance to tracked vehicles traveling on slopes; The calculation of vehicle ground resistance consists of the sum of the vehicle's bulldozing resistance and the additional driving resistance on slopes, expressed as: .

[0016] Among them, such as Figure 3 As shown, the loading of vehicle-ocean current characteristics specifically involves the following steps S51-S53: Step S51: Assessment of seabed current characteristics: The surface current velocity is initialized based on the wave level in open water. The surface current velocity is expressed as: In the formula: This refers to the surface current velocity at the sea surface. v The wind speed for the target sea area can be found in the day's weather forecast. The laminar current velocity at the location of the amphibious vehicle on the seabed, calculated based on the surface current velocity, is expressed as: In the formula: The velocity of ocean currents on the seabed; h The characteristic depth for ocean current attenuation is 15-30 meters. The average seawater depth at step j is expressed as: Step S32: Estimation of vehicle viscous water resistance coefficient: The viscous drag coefficient of amphibious vehicles is related to the vehicle's frontal surface. Simplifying the amphibious vehicle into a regular cube, the frontal cross-sectional area and yaw angle are related, expressed as: In the formula, For the first j The water-facing cross-section of an amphibious vehicle with a stride length; L, B, H These are the length, width, and height of the amphibious vehicle, respectively. Therefore, the relationship between the viscous water resistance coefficient and the yaw angle is expressed as: In the formula, For the first j The viscous water resistance coefficient of amphibious vehicles with a stride length; Step S33: Calculation of vehicle ocean current resistance: Based on the ocean current velocity, the vehicle's upstream cross-sectional area, the viscous water resistance coefficient, and the vehicle's underwater speed, the ocean current resistance of the vehicle is calculated and expressed as: In the formula, For the first j Ocean current resistance of amphibious vehicles with stride length; The density of seawater; The underwater speed of the amphibious vehicle is set as a constant speed, and a target speed can be set in each step interval.

[0017] (III) Beneficial Effects Compared with existing technologies, this invention provides an underwater path planning method for amphibious vehicles based on optimal energy loss, including underwater land-ocean current environment construction, land mechanical property loading, and ocean current mechanical property loading, in order to solve the energy optimization management in underwater path planning of amphibious tracked vehicles.

[0018] Specifically, the method includes: constructing a three-dimensional grid map, integrating seabed topography, ocean current direction, and obstacle information to form a topography-ocean current composite map; applying a particle swarm optimization algorithm to generate a series of control points between the starting and ending points to ensure the path maintains a safe altitude relative to the seabed; calculating the terrain slope, yaw angle, and interaction forces between the vehicle and the ground and ocean currents for each path step, quantifying ground resistance and ocean current resistance; evaluating the energy loss for each step based on resistance and travel distance, and accumulating the total loss; iteratively optimizing the path through collision detection and energy loss minimization criteria, and finally selecting the optimal path with the minimum energy loss.

[0019] This invention achieves energy-efficient underwater path planning by comprehensively considering terrain, ocean currents, and vehicle characteristics, thereby improving the endurance and driving safety of amphibious vehicles. Attached Figure Description

[0020] Figure 1 A flowchart of an underwater path planning method for amphibious vehicles based on optimal energy loss, provided in an embodiment of the present invention; Figure 2 A flowchart illustrating the loading of ocean current dynamics characteristics provided in an embodiment of the present invention; Figure 3 A flowchart illustrating the loading of ground mechanical properties is provided for an embodiment of the present invention. Figure 4 This is a schematic diagram of the ground-obstacle-flow field environment provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the underwater path planning results for amphibious vehicles based on optimal energy loss, provided in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0022] To address the aforementioned technical problems, this invention provides an underwater path planning method for amphibious vehicles based on optimal energy loss, such as... Figure 1 As shown, the underwater path planning method for amphibious vehicles includes the following steps: Step S1: Underwater map construction; Step S2: Perform route planning; Step S3: Load terrain slope information; Step S4: Load vehicle-ground characteristics; Step S5: Load vehicle-ocean current characteristics; Step S6: Energy loss assessment; Step S7: Determine if a collision has occurred; Step S8: Determine if the path is optimal.

[0023] In step S1, underwater map construction includes: Based on the scope of the target sea area, plan the map size and initialize a three-dimensional spatial grid map. The map structure size is represented as length × width × height. Plan a sea area grid map of a certain length, width and depth for amphibious vehicle underwater path planning. That is, plan a water area space with a grid map length of 200 meters, a width of 200 meters and a water depth of 15 meters, i.e., a 200×200×15 sea area for amphibious vehicle underwater path planning. Among them, based on the pre-detected seabed topographic data (such as multibeam bathymetry data), the row vector of the matrix is ​​the length of the target sea area (200 meters), the column vector is the width of the mapped target sea area (200 meters), and the values ​​in the matrix are the elevations of the topography. Among them, the ocean current direction is set according to the wind direction of the target sea area detected in the preliminary detection, and the indication point is set in the 200×200×15 sea area. The indication point is indicated by the arrow to show the ocean current direction. Among them, obstacles are set according to the pre-detected seabed topographic obstacle information and suspected non-communication areas. The obstacles are not limited to the shape. In this embodiment, they are represented by a sphere. This involves loading digital seabed topography data, ocean current direction data, and obstacle distribution information based on the previously detected target sea area topography and wind speed, and overlaying these onto a regional raster map to form a topography-ocean current composite map, such as... Figure 4 As shown.

[0024] In step S2, path planning is performed: Based on the topographic-ocean current composite map, the Particle Swarm Optimization (PSO) algorithm is applied for global underwater path planning (path planning methods such as A-Star, RRT, and PSO intelligent algorithm can all be used to achieve this). The starting and ending points of the tasks performed by the amphibious vehicle are set according to actual needs. In this embodiment, (1, 1) in the topographic-ocean current composite map is set as the starting point and (200, 200) is set as the ending point. The number of calculation iterations is set to 200, and the number of iterations can be adjusted according to the map size and calculation efficiency. The PSO (Particle Swarm Optimization) algorithm is applied for underwater path planning of amphibious vehicles. Based on the accuracy requirements of path planning, a series of control points are generated between the starting point and the ending point. In this embodiment, the number of control points is set to 10. The terrain interpolation function forces the control point to remain at a safe height, ensuring that the amphibious vehicle's path remains in close contact with the terrain and does not collide with the seabed. The safe height is consistent with the vehicle's center of gravity height. If the vehicle's center of gravity height cannot be accurately obtained, it is simplified to half of the vehicle's height.

[0025] In step S3, terrain slope information is loaded: Planning each path requires deriving the 3D coordinates of the control points, as shown below: In the formula, n To control the number of points, in this embodiment... n =10; Two adjacent control points are defined as a step size. The yaw and slope information for each step size are calculated as follows: In the formula: , For the first j Yaw angle and slope angle of one step length.

[0026] In step S4, the vehicle-ground characteristics are loaded: Based on the seabed soil type information of the target sea area, the mechanical property parameters of the soil are loaded. Combined with the weight, structure and size information of the amphibious vehicle, the vehicle-ground interaction characteristics are quantified, and the ground resistance of the amphibious vehicle underwater travel is calculated.

[0027] In step S5, the vehicle-ocean current characteristics are loaded: Based on the hydrological information of the target sea area, the mechanical properties of the underwater ocean current are loaded, and combined with the shape, structure and size information of the amphibious vehicle, the interaction characteristics between the vehicle and the ocean current are quantified, and the ocean current resistance of the amphibious vehicle underwater is calculated.

[0028] In step S6, energy loss assessment is performed. Based on the ground resistance, ocean current resistance, and travel distance of the amphibious vehicle underwater, the energy loss between each pair of adjacent control points is calculated, and then the energy loss of the entire path is calculated by summing the results, expressed as: In the formula, For the first j Energy loss per step length along the path; For the first j Vehicle ground resistance per step length; For the first j The vehicle's resistance to ocean currents is measured in steps. No. j The path distance of each step is expressed as: The total energy loss for the entire path is calculated by summing the energy loss at each step, and expressed as follows: .

[0029] In step S7, it is determined whether a collision has occurred: Check if the currently planned path collides with an obstacle. If no collision is found, proceed to the next step; if a collision is found, replan the path. In step S8, it is determined whether the path is optimal: The criterion for determining the optimal path is to minimize the energy loss during the planning from the starting point to the ending point. After the particle swarm optimization algorithm completes its loop, the amphibious vehicle selects the optimal path to execute. Figure 5 As shown.

[0030] Among them, such as Figure 2 As shown, the loading of vehicle-ground characteristics in step S4 specifically includes the following steps S41-S43: Step S41: Ground mechanical property assessment: Based on the pre-surveyed seabed soil conditions, the bearing capacity of the ground is quantified using the basic mechanical properties of the soil, expressed as: In the formula: z j For amphibious vehicles to travel j The amount of seabed subsidence per step; The underwater grounding pressure of the vehicle; , For cohesion and friction modulus; b Track width; n The subsidence index is used; in this embodiment, the seabed surface is sandy, and its cohesion, friction, and subsidence indices are 3.4e-2. 0.8e-3 0.55 and above are calibrated according to the test results of seabed soil characteristics; Step S42: Calculation of vehicle bulldozing resistance: The seabed is soft soil, resulting in significant bulldozing resistance for amphibious tracked vehicles. The longitudinal ground resistance is expressed as: In the formula: For longitudinal soil resistance of tracked vehicles; ρ The density of seabed sand is taken as 2.0 g / cm³. The internal friction angle of the soil is taken as 28°. Step S43: Calculation of vehicle ground resistance: When an amphibious vehicle travels on a slope, the vehicle's underwater weight will generate additional drag, which is represented as: In the formula: Adds travel resistance to tracked vehicles traveling on slopes; The calculation of vehicle ground resistance consists of the sum of the vehicle's bulldozing resistance and the additional driving resistance on slopes, expressed as: .

[0031] Among them, such as Figure 3 As shown, the loading of vehicle-ocean current characteristics specifically involves the following steps S51-S53: Step S51: Assessment of seabed current characteristics: The surface current velocity is initialized based on the wave level in open water. The surface current velocity is expressed as: In the formula: This refers to the surface current velocity at the sea surface. v The wind speed for the target sea area can be found in the day's weather forecast. The laminar current velocity at the location of the amphibious vehicle on the seabed, calculated based on the surface current velocity, is expressed as: In the formula: The velocity of ocean currents on the seabed; h The characteristic depth for ocean current attenuation is 15-30 meters. The average seawater depth at step j is expressed as: Step S32: Estimation of vehicle viscous water resistance coefficient: The viscous drag coefficient of amphibious vehicles is related to the vehicle's frontal surface. Simplifying the amphibious vehicle into a regular cube, the frontal cross-sectional area and yaw angle are related, expressed as: In the formula, For the first j The water-facing cross-section of an amphibious vehicle with a stride length; L, B, H These are the length, width, and height of the amphibious vehicle, respectively. Therefore, the relationship between the viscous water resistance coefficient and the yaw angle is expressed as: In the formula, For the first j The viscous water resistance coefficient of amphibious vehicles with a stride length; Step S33: Calculation of vehicle ocean current resistance: Based on the ocean current velocity, the vehicle's upstream cross-sectional area, the viscous water resistance coefficient, and the vehicle's underwater speed, the ocean current resistance of the vehicle is calculated and expressed as: In the formula, For the first j Ocean current resistance of amphibious vehicles with stride length; The density of seawater; The underwater speed of the amphibious vehicle is set as a constant speed, and a target speed can be set in each step interval.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for underwater path planning of amphibious vehicles based on optimal energy loss, characterized in that, The underwater path planning method for amphibious vehicles includes the following steps: Step S1: Underwater map construction; Step S2: Perform route planning; Step S3: Load terrain slope information; Step S4: Load vehicle-ground properties; Step S5: Load vehicle-ocean current characteristics; Step S6: Energy loss assessment; Step S7: Determine if a collision has occurred; Step S8: Determine if the path is optimal.

2. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 1, characterized in that, In step S1, underwater map construction: Based on the scope of the target sea area, plan the map size, initialize a three-dimensional spatial raster map, and represent the map structure size as length × width × height. Plan a sea area raster map of a certain length, width and depth for underwater path planning of amphibious vehicles. Among them, based on the pre-detected seabed topographic data, the row vector of the matrix represents the length of the target sea area, the column vector represents the width of the mapped target sea area, and the values ​​in the matrix represent the elevation of the topography. Among them, the ocean current direction is set according to the wind direction of the target sea area detected in the preliminary detection, and the indication point is set in the sea area, with the indication point using arrows to indicate the ocean current direction; Among them, obstacles were set up based on the pre-detected seabed topographic obstacle information and suspected non-communication areas; Based on the target sea area topography and wind speed detected in the preliminary survey, digital seabed topography data, ocean current direction data, and obstacle distribution information are loaded and overlaid onto the sea area raster map to form a topography-ocean current composite map.

3. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 2, characterized in that, In step S2, path planning is performed: Based on the topographic-ocean current composite map, the Particle Swarm Optimization (PSO) algorithm is applied for global underwater path planning; the starting and ending points of the tasks performed by the amphibious vehicle are set according to actual needs, and the number of calculation iterations is set. The PSO (Particle Swarm Optimization) algorithm is applied for underwater path planning of amphibious vehicles. Based on the accuracy requirements of path planning, a series of control points are generated between the starting point and the ending point. The terrain interpolation function forces the control point to remain at a safe height, ensuring that the amphibious vehicle's path remains in close contact with the terrain and does not collide with the seabed. The safe height is consistent with the vehicle's center of gravity height. If the vehicle's center of gravity height cannot be accurately obtained, it is simplified to half the vehicle's height.

4. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 3, characterized in that, In step S3, the terrain slope information is loaded: Planning each path requires deriving the 3D coordinates of the control points, as shown below: In the formula, n The number of control points; two adjacent control points are defined as a step size. The yaw and slope information for each step size are calculated as follows: In the formula: , For the first j Yaw angle and slope angle of one step length.

5. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 4, characterized in that, In step S4, the vehicle-ground characteristics are loaded: Based on the seabed soil type information of the target sea area, the mechanical property parameters of the soil are loaded. Combined with the weight, structure and size information of the amphibious vehicle, the vehicle-ground interaction characteristics are quantified, and the ground resistance of the amphibious vehicle underwater travel is calculated.

6. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 5, characterized in that, In step S5, the vehicle-ocean current characteristics are loaded: Based on the hydrological information of the target sea area, the mechanical properties of the underwater ocean current are loaded, and combined with the shape, structure and size information of the amphibious vehicle, the interaction characteristics between the vehicle and the ocean current are quantified, and the ocean current resistance of the amphibious vehicle underwater is calculated.

7. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 6, characterized in that, In step S6, energy loss assessment: Based on the ground resistance, ocean current resistance, and travel distance of the amphibious vehicle underwater, the energy loss between each pair of adjacent control points is calculated, and then the energy loss of the entire path is calculated by summing the results, expressed as: In the formula, For the first j Energy loss per step length along the path; For the first j Vehicle ground resistance per step length; For the first j The vehicle's resistance to ocean currents is measured in steps. No. j The path distance of each step is expressed as: The total energy loss for the entire path is calculated by summing the energy loss at each step, and expressed as follows: 。 8. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 7, characterized in that, In step S7, it is determined whether a collision has occurred: Check if the currently planned path collides with an obstacle. If no collision is found, proceed to the next step; if a collision is found, replan the path. In step S8, it is determined whether the path is optimal: The minimum energy loss from the starting point to the ending point is selected as the criterion for determining the optimal path. After the particle swarm algorithm loop ends, the amphibious vehicle selects the optimal path to execute.

9. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 8, characterized in that, The loading of vehicle-ground characteristics in step S4 specifically includes the following steps S41-S43: Step S41: Ground mechanical property assessment: Based on the pre-surveyed seabed soil conditions, the bearing capacity of the ground is quantified using the basic mechanical properties of the soil, expressed as: In the formula: z j For amphibious vehicles to travel j The amount of seabed subsidence per step; The underwater grounding pressure of the vehicle; , For cohesion and friction modulus; b This refers to the width of the track. n The depression index; Step S42: Calculation of vehicle bulldozing resistance: The seabed is soft soil, resulting in significant bulldozing resistance for amphibious tracked vehicles. The longitudinal ground resistance is expressed as: In the formula: For longitudinal soil resistance of tracked vehicles; ρ The density of seabed sand; It is the internal friction angle of the soil; Step S43: Calculation of vehicle ground resistance: When an amphibious vehicle travels on a slope, its underwater weight will generate additional drag, which can be represented as: In the formula: Adds travel resistance to tracked vehicles traveling on slopes; The calculation of vehicle ground resistance consists of the sum of the vehicle's bulldozing resistance and the additional driving resistance on slopes, expressed as: 。 10. The amphibious vehicle underwater path planning method based on optimal energy loss as described in claim 9, characterized in that, The loading of vehicle-ocean current characteristics specifically involves the following steps S51-S53: Step S51: Assessment of seabed current characteristics: The surface current velocity is initialized based on the wave level in open water. The surface current velocity is expressed as: In the formula: This refers to the surface current velocity at the sea surface. v Wind speed in the target sea area; The laminar current velocity at the location of the amphibious vehicle on the seabed, calculated based on the surface current velocity, is expressed as: In the formula: The velocity of ocean currents on the seabed; h This represents the characteristic depth of ocean current attenuation. The average seawater depth at step j is expressed as: Step S32: Estimation of vehicle viscous water resistance coefficient: The viscous drag coefficient of amphibious vehicles is related to the vehicle's frontal surface. Simplifying the amphibious vehicle into a regular cube, the frontal cross-sectional area and yaw angle are related, expressed as: In the formula, For the first j The water-facing cross-section of an amphibious vehicle with a stride length; L, B, H These are the length, width, and height of the amphibious vehicle, respectively. Therefore, the relationship between the viscous water resistance coefficient and the yaw angle is expressed as: In the formula, For the first j The viscous water resistance coefficient of amphibious vehicles with a stride length; Step S33: Calculation of vehicle ocean current resistance: Based on the ocean current velocity, the vehicle's upstream cross-sectional area, the viscous water resistance coefficient, and the vehicle's underwater speed, the ocean current resistance of the vehicle is calculated and expressed as: In the formula, For the first j Ocean current resistance of amphibious vehicles with stride length; The density of seawater; The underwater speed of the amphibious vehicle.

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