Method for establishing virtual section buoy motion model at small scale

Abstract

The method for establishing a virtual profile buoy motion model at a small scale belongs to the technical field of virtual profile buoys. The method comprises the following steps: S1, establishing an ocean collision model, wherein the ocean collision model comprises a profile buoy collision model and an ocean current particle collision model, the profile buoy collision model is an ocean profile observation buoy composed of a plurality of capsule-shaped collision bodies, and the ocean current particle collision model comprises a plurality of spherical current particles; S2, performing self-collision detection on the spherical current particles and performing collision detection on the profile observation buoy and the spherical current particles; and S3, calculating the force acting on the profile observation buoy in two states of the profile observation buoy being located on water and in water, respectively, and synchronously updating the motion parameters of the profile observation buoy and the spherical current particles based on the force. The method realizes high-precision, low-computational-load and real-time stable motion simulation of the ocean profile observation buoy at a small scale.

Description

Technical Field

[0001] This invention relates to the technical field of virtual profile buoys, and specifically to a method for establishing a motion model of a virtual profile buoy at a small scale. Background Technology

[0002] Ocean profiling buoys are crucial equipment for marine environmental monitoring. Simulating their motion characteristics under the influence of ocean currents is of great significance for buoy structural design, sea state prediction, and operational control. Currently, simulation methods for virtual marine environments mainly include numerical simulation, physical model experiments, and statistical analysis based on field / remote sensing data. Among these, numerical simulation is the mainstream method in physical oceanography research, and commonly used simulation analysis models include wave spectrum models, geometric models, physical models, and particle models.

[0003] However, existing technologies have the following technical problems: Most virtual ocean models are constructed for large-scale ocean areas and cannot accurately simulate the motion of ocean particles at small scales (the virtual ocean simulation domain has a horizontal range of ≤100m×100m, a vertical depth of ≤50m, and the effective interaction range between the flow field and the buoy is ≤10 times the maximum external size of the buoy). Consequently, they cannot accurately depict the effect of ocean currents on ocean profile observation buoys at small scales. For the motion simulation of ocean profile observation buoys, existing methods mostly use macroscopic fluid dynamics equations or semi-empirical models. High-precision fluid dynamics methods require extremely high grid resolution and computational resources, making it difficult to achieve real-time interaction. Moreover, macroscopic equations cannot accurately depict the complex microscopic physical processes near the buoy surface. Some technologies use particle methods to simulate the phenomena of jet streams and sprays in the ocean environment, but these only use particles for visual effects. The simulated particles lack rigorous physical properties, resulting in a disconnect between visual and physical aspects and failing to simulate the physical motion of the buoy and ocean currents.

[0004] Therefore, how to utilize the intuitiveness and flexibility of particle systems, combined with the rigor of rigid body dynamics, to achieve high physical fidelity and low computational cost in small-scale simulation of ocean profile observation buoy motion has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of this, the main objective of the present invention is to provide a method for establishing a virtual profile buoy motion model at a small scale, in order to at least partially solve the above-mentioned technical problems.

[0006] To achieve the above objectives, as a first aspect of the present invention, a method for establishing a virtual profile buoy motion model at a small scale is proposed, comprising the following steps: S1: Establish an ocean collision model, which includes a profile buoy collision model and an ocean current particle collision model. The profile buoy collision model is an ocean profile observation buoy composed of several capsule-shaped collision bodies, and the ocean current particle collision model includes several spherical water current particles. S2: Perform self-collision detection on the spherical water flow particles, and perform collision detection between the ocean profile observation buoy and the spherical water flow particles; S3: The ocean profile observation buoy is in two states in the seawater, namely above water and underwater. The forces acting on the ocean profile observation buoy are calculated. Based on the forces, the motion parameters of the ocean profile observation buoy and the spherical water flow particles are updated synchronously to realize the simulation of the single motion state of the ocean profile observation buoy. The continuous motion simulation of the ocean profile observation buoy is achieved by repeatedly executing S1 to S3 and updating the frames continuously.

[0007] In one possible implementation, the number of capsule-shaped impactors is four, and the four capsule-shaped impactors are rigidly connected as an integrated structure, with the outer contour matching the actual outer contour of the ocean profile observation buoy.

[0008] In one possible implementation, when constructing the ocean current particle collision model, different particle radii are set according to the distance between the spherical current particles and the ocean profile observation buoy. The particle radius is smaller in the region closer to the ocean profile observation buoy and larger in the region farther away. The first layer of spherical current particles is taken as the layer closest to the ocean profile observation buoy, and the radius of the first layer of spherical current particles is the base radius. The direction from the ocean profile observation buoy to the first layer of spherical current particles is taken as outward, and several layers of spherical current particles are formed outward. The radius of the spherical current particles is larger as they move outward. The radius of each layer of spherical current particles is equal to the product of the base radius and the expansion coefficient, and the expansion coefficient is not less than 1.

[0009] In one possible implementation, before performing collision detection between the ocean profile observation buoy and the spherical water flow particles in S2, a spherical detection area is constructed with the center of gravity of the ocean profile observation buoy as the center of the sphere and a set length as the radius. The spherical detection area completely surrounds all capsule-shaped colliders, and collision detection is performed only on the spherical water flow particles within the area.

[0010] In one possible implementation, the collision detection process between the ocean profile observation buoy and the spherical water flow particle in S2 is as follows: each capsule-shaped collider is detected against the spherical water flow particle, the nearest point of the line segment from the center of the spherical water flow particle to the central axis of the capsule-shaped collider is calculated, the actual distance from the particle center to the nearest point is calculated, and this distance is compared with the sum of the radii of the capsule-shaped collider and the spherical water flow particle to determine whether a collision has occurred.

[0011] In one possible implementation, when the ocean profiling buoy in S3 is in a state above water, the motion parameters after the collision between spherical water flow particles are updated first, and then the motion parameters after the collision between the spherical water flow particles and the ocean profiling buoy are updated.

[0012] In one possible implementation, when the ocean profile observation buoy is in a floating state, the coordinates of the center of buoyancy are first calculated using the volume of the fluid it displaces as the integration domain. Then, based on the relative position of the center of gravity and the center of buoyancy and the buoy's tilt angle, the floating righting torque that restores the buoy to a normal state is calculated. The floating righting torque is one of the forces that update the buoy's motion parameters.

[0013] In one possible implementation, when the ocean profile observation buoy is in the water, the buoyancy is calculated based on the overall volume of the ocean profile observation buoy, and the calculation process for the collision force between spherical water flow particles and the ocean profile observation buoy is the same as when it is in the water.

[0014] In one possible implementation, when the ocean profile observation buoy is in the water, the underwater righting moment in three spatial directions is calculated based on the relative position of the center of gravity and the center of buoyancy and the tilt angle of the buoy in different directions. The calculation rules for the righting moment in each direction are consistent, only the values ​​of the tilt angles are different.

[0015] In one possible implementation, each time S1 to S3 is executed, the collision and motion parameters of the spherical water flow particles that are far from the ocean profile observation buoy are calculated first, in order of distance from far to near. Then, the force of the colliding spherical water flow particles that are close to the ocean profile observation buoy is calculated and the motion state of the ocean profile observation buoy is updated.

[0016] Based on the above technical solution, it can be seen that the method for establishing a virtual profile buoy motion model at a small scale according to the present invention has at least one of the following beneficial effects compared with the prior art: 1. An integrated, rigidly connected capsule-shaped collision body is used to construct a collision model for profile buoys, which accurately matches the shape contour of irregular ocean profile observation buoys, solving the problem of low accuracy in collision modeling of irregular buoys and providing a reliable geometric basis for collision detection and motion simulation; 2. The radius of the spherical water flow particles is adaptively set according to their distance from the buoy. While ensuring the accuracy of near-field collision detection of the buoy, the number of far-field particles is reduced, which greatly reduces the amount of simulation calculation and improves the running efficiency of virtual simulation. 3. Before collision detection, a spherical screening area is constructed based on the buoy's center of gravity. Collision detection is performed only on particles within the area to eliminate invalid computational objects, further reducing the computational load and adapting to the real-time interactive requirements of small-scale simulations. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the method for establishing a virtual profile buoy motion model according to the present invention. Figure 2 This is a structural schematic diagram of the cross-sectional buoy collision model of the present invention; Figure 3 This is a schematic diagram of the structure of the ocean current particle collision model of the present invention; Figure 4 This is a schematic diagram of the steady-state and tilt states of the ocean profile observation buoy of the present invention; Figure 5 This is a schematic diagram of the tilting of the ocean profile observation buoy of the present invention in the water; Figure descriptions: 1. First capsule-shaped collider; 2. Second capsule-shaped collider; 3. Third capsule-shaped collider; 4. Fourth capsule-shaped collider. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of the invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0021] Existing technologies suffer from problems such as low accuracy in collision modeling of buoys for irregular ocean profile observation, high computational cost of spherical water flow particles, low collision detection efficiency, incomplete simulation of the forces acting on the buoy above and below water, poor physical fidelity in motion simulation, and difficulty in achieving real-time interaction. Through in-depth research, it was found that by constructing a buoy collision model using an integrated rigidly connected capsule-shaped collision body, adaptively setting the radius of spherical water flow particles according to distance, constructing a spherical region based on the buoy's center of gravity to screen collision objects, accurately calculating the forces and righting moments based on the above and below water states, and executing particle and buoy motion calculations in an orderly manner from far to near in each frame, it is possible to achieve high-precision, low-computational-cost, physically faithful, and real-time stable motion simulation of virtual profile buoys at a small scale, accurately restoring the real motion characteristics of buoys under the action of ocean currents.

[0022] Therefore, as Figure 1As shown, the inventors have proposed a method for establishing a virtual profile buoy motion model at a small scale, comprising the following steps: S1: Establish an ocean collision model, which includes a profile buoy collision model and an ocean current particle collision model. The profile buoy collision model is an ocean profile observation buoy composed of several capsule-shaped collision bodies, and the ocean current particle collision model includes several spherical ocean current particles. The ocean collision model is mainly divided into two parts: the ocean profile observation buoy collision model and the ocean current particle collision model. Because the ocean profile observation buoy has an irregular shape, multiple collision units need to be combined to simulate its shape. Commonly used collision bodies include spherical, capsule-shaped, and cubic collision bodies. However, due to the characteristics of this ocean profile observation buoy's structure, several capsule-shaped collision bodies are mainly used in combination to simulate its shape.

[0023] The collision model of spherical water flow particles is designed because spherical particles can better simulate the movement of water flow. Since spherical water flow particles are relatively small, a large number of spherical water flow particles are needed to more realistically simulate the marine environment, resulting in a large amount of computation in the virtual environment. To reduce the amount of computation, different volume sizes are set according to their distance from the ocean profile observation buoy. Spherical water flow particles closer to the ocean profile observation buoy have smaller volumes, while those farther away have relatively larger volumes. The collision model of spherical water flow particles is designed accordingly.

[0024] S2: Perform self-collision detection on the spherical water flow particles, and perform collision detection between the ocean profile observation buoy and the spherical water flow particles; S3: The ocean profile observation buoy is in two states in the seawater, namely above water and underwater. The forces acting on the ocean profile observation buoy are calculated. Based on the forces, the motion parameters of the ocean profile observation buoy and the spherical water flow particles are updated synchronously to realize the simulation of the single motion state of the ocean profile observation buoy. The continuous motion simulation of the ocean profile observation buoy is achieved by repeatedly executing S1 to S3 and updating the frames continuously.

[0025] In one possible implementation, the number of capsule-shaped impactors is four, and the four capsule-shaped impactors are rigidly connected as an integrated structure, with the outer contour matching the actual outer contour of the ocean profile observation buoy.

[0026] In this embodiment, four capsule-shaped colliders are used to simulate the buoy's shape. The first capsule-shaped collider 1, the second capsule-shaped collider 2, the third capsule-shaped collider 3, and the fourth capsule-shaped collider 4 are all adapted to the actual shape of the buoy, ensuring that the contours of the colliders coincide with the buoy's contour. The use of integrated, rigidly connected capsule-shaped colliders to construct the profile buoy collision model accurately matches the contour of irregular ocean profile observation buoys, solving the problem of low accuracy in collision modeling of irregular buoys and providing a reliable geometric basis for collision detection and motion simulation.

[0027] In one possible implementation, when constructing the ocean current particle collision model, different particle radii are set according to the distance between the spherical current particles and the ocean profile observation buoy. The particle radius is smaller in the region closer to the ocean profile observation buoy and larger in the region farther away. The first layer of spherical current particles is the layer closest to the ocean profile observation buoy, and the radius of the first layer of spherical current particles is the base radius. The direction from the ocean profile observation buoy to the first layer of spherical current particles is taken as outward, and several layers of spherical current particles are formed outward. The radius of the spherical current particles in the outermost layer is larger. The radius of each layer of spherical current particles is equal to the product of the base radius and the expansion coefficient. The expansion coefficient is not less than 1, that is, the expansion coefficient of the first layer of spherical current particles is 1, and the expansion coefficient of the remaining layers of spherical current particles is greater than 1, with the expansion coefficient increasing further outward.

[0028] It should be noted that the radius of the spherical water flow particles can be set to multiple discrete values ​​based on the distance from the buoy, such as two, three, or more, with a fixed expansion coefficient set between each radius. For particle interactions at the boundaries of different radius regions, the collision response model based on the expansion coefficient k provided in this embodiment of the invention is still used, where k represents the ratio of two adjacent radius values. Those skilled in the art will understand that by setting multiple discrete radii, a continuously changing radius distribution can be approximated, and the collision handling logic between particles at the boundaries is consistent with the two-radius case.

[0029] In this embodiment, spherical water flow particles with different radii are set according to their distance from the ocean profile observation buoy. Since the collision model of the spherical water flow particles is spherical, their design principle is consistent. This part only takes the two sets of spherical water flow particles with different radii closest to the ocean profile observation buoy as examples. The particles farther from the buoy have larger radii, and their calculation method is the same. The spherical water flow particles adaptively set their radii according to their distance from the buoy (smaller for closer particles and larger for farther particles). While ensuring the accuracy of near-field collision detection of the buoy, this reduces the number of far-field particles, significantly reduces the amount of simulation calculation, and improves the running efficiency of virtual simulation.

[0030] In one possible implementation, S2 performs self-collision detection on the spherical water flow particles as follows: the radius of the spherical water flow particle closest to the ocean profile observation buoy is set as a fixed value, and the radius of the relatively distant spherical water flow particles is the product of this fixed value and an expansion coefficient greater than 1. By comparing whether the distance between the centers of the two spherical water flow particles is less than the sum of their radii, it is determined that a self-collision has occurred; otherwise, it is determined that no collision has occurred.

[0031] In this embodiment, self-collision detection between spherical water flow particles is first performed. The radius of the first layer of spherical water flow particles closest to the ocean profile observation buoy is set as R, and the radius of the second layer of spherical water flow particles relatively far away is set as kR, where R is the basic radius of the spherical water flow particle, and k is the expansion coefficient of the spherical water flow particle, which is not less than 1. Since the two spherical water flow particles are spherical particles, the distance between the centers of the two particles is compared to determine whether the particles are in contact.

[0032] A collision is considered to have occurred when the distance between the centers of the spheres is less than the sum of their radii; otherwise, it is considered not to have occurred. To reduce computational cost, the radius of each particle is searched. All particles within the area are subject to distance detection only. This is the set collision detection range coefficient.

[0033] In one possible implementation, before performing collision detection between the ocean profile observation buoy and the spherical water flow particles in S2, a spherical detection area is constructed with the center of gravity of the ocean profile observation buoy as the center of the sphere and a set length as the radius. The spherical detection area completely surrounds all capsule-shaped colliders, and collision detection is performed only on the spherical water flow particles within the area.

[0034] In this embodiment, based on a pre-constructed ocean profiling buoy model rigidly connected by several capsule-shaped impactors, the overall center of gravity of the ocean profiling buoy is calculated through weighted summation based on the mass and spatial coordinates of each capsule-shaped impactor. This center of gravity coordinates are then determined as the center coordinates of the spherical detection area. The radius of the spherical detection area is set according to the overall dimensions of the ocean profiling buoy. This radius is not less than half of the maximum overall outer dimensions of the ocean profiling buoy, ensuring that the spherical detection area completely surrounds all capsule-shaped impactors, with no impactor exceeding the detection area's boundaries. Based on the determined center coordinates and the radius of the spherical detection area, a three-dimensional spherical detection area is constructed in a virtual ocean environment. This area serves as the effective calculation range for subsequent collision detection. The algorithm iterates through all spherical water flow particles in the virtual ocean environment, determining whether the center coordinates of each particle fall within the aforementioned spherical detection area. Only particles whose center coordinates are within this area are marked as particles to be detected; particles whose center coordinates are outside the detection area are excluded and not included in subsequent collision detection calculations. Based on the selected particles within the spherical detection area, subsequent collision detection operations are performed one by one with each capsule-shaped collider of the ocean profile observation buoy, thus completing collision sensing.

[0035] Before collision detection, a spherical detection area is constructed with the buoy's center of gravity as the center and a sufficient radius. This area completely surrounds all capsule-shaped collision objects, ensuring that all spherical water particles that may collide with the buoy are included in the detection range, eliminating missed collisions and guaranteeing the physical accuracy and completeness of collision perception. Collision detection is performed only on spherical water particles within the spherical detection area, directly excluding far-field particles outside the area that have no collision potential. This significantly reduces the number of objects to be calculated for collision detection, avoids the waste of computational power caused by full particle traversal detection, and significantly reduces the computational resource consumption of virtual simulation. In line with the simulation characteristics of a small-scale virtual ocean environment, while ensuring the precision of near-field collision detection for the buoy, the calculation process is simplified, the computation time of a single frame simulation is shortened, and the real-time requirement of continuous frame loops in steps S1-S3 is met, achieving smooth real-time simulation of buoy motion. The pre-region screening simplifies the subsequent collision detection process, reduces redundant algorithm calculations, and avoids problems such as simulation stuttering and parameter update delays caused by an excessive number of particles, ensuring the stability and reliability of the entire buoy motion simulation process.

[0036] In one possible implementation, the collision detection process between the ocean profile observation buoy and the spherical water flow particle in S2 is as follows: each capsule-shaped collider is detected against the spherical water flow particle, the nearest point of the line segment from the center of the spherical water flow particle to the central axis of the capsule-shaped collider is calculated, the actual distance from the particle center to the nearest point is calculated, and this distance is compared with the sum of the radii of the capsule-shaped collider and the spherical water flow particle to determine whether a collision has occurred.

[0037] In this embodiment of the application, after detecting the self-collision between spherical water flow particles, the collision between the ocean profile observation buoy and the spherical water flow particles is performed. Since the collision body of the ocean profile observation buoy is composed of multiple capsule-shaped collision bodies, each collision body needs to be detected to collide with the spherical water flow particles separately.

[0038] The main process for collision detection between the capsule-shaped collider of an ocean profiling buoy and the spherical water flow particles of the ocean current particle collision model is as follows: Taking the first capsule-shaped collider 1 as an example, the two endpoints of the first capsule-shaped collider 1 are A and B, and the radius is... Center of mass: The quality is The speed is The center of the spherical water flow particle being tested is , radius is The center of mass coincides with the center, and the mass is The speed is Set the collision elasticity coefficient to e, and its value can be freely set between 0 and 1.

[0039] First, calculate the closest point from the center of the spherical water flow particle to the first capsule-shaped collider 1: in, Let be the direction vector of the axis of the capsule-shaped collider. Let A be the position vector from point A to the center of the spherical water flow particle, and let the projection parameter t be: Constrained projection parameters on the axis line segment : The closest point from the particle center to the capsule axis is: in, It is the closest point (three-dimensional spatial coordinate point) on the line segment from the center of the spherical water flow particle to the center of the capsule-shaped collider. These are the constraint projection parameters on the axis line segment. Let be the direction vector of the axis of the capsule-shaped collider.

[0040] From the particle center to the nearest point The distance vector is: in, From the particle center to the nearest point The distance vector represents the distance from the nearest point on the capsule axis. Pointing towards the center of spherical water flow particles A three-dimensional vector, The coordinates of the center of the spherical water particle (a point in three-dimensional space). It is the closest point (three-dimensional point) on the line segment from the center of the spherical water flow particle to the center of the capsule-shaped collider.

[0041] From the particle center to the nearest point The actual distance is: in, From the particle center to the nearest point The actual distance From the particle center to the nearest point The distance vector.

[0042] Determine whether a collision has occurred using the following formula: in, The radius of the first capsule-shaped collider. Let be the radius of the spherical water flow particle. If this condition is met, a collision is considered to have occurred; otherwise, no collision is considered to have occurred, and the spherical water flow particle does not need to participate in subsequent calculations.

[0043] To reduce the computational burden of collision detection, the center of gravity of the ocean profile observation buoy is first used as the center of the sphere. With a radius of 1, this spherical region completely surrounds all the different collision objects of the ocean profiling buoy. By detecting spherical water flow particles within this spherical region and only performing collision detection on these particles with the ocean profiling buoy, the collision detection between the ocean profiling buoy and the spherical water flow particles is completed.

[0044] After the collision detection is completed, a response to the detection results is required. Since ocean profile observation buoys mainly exist in two states in seawater, namely above the water and underwater, this application mainly focuses on motion response in these two states.

[0045] In one possible implementation, when the ocean profiling buoy in S3 is in a state above water, the motion parameters after the collision between spherical water flow particles are updated first, and then the motion parameters after the collision between the spherical water flow particles and the ocean profiling buoy are updated.

[0046] In one possible implementation, when calculating the motion parameters after a collision between spherical water flow particles, the mass ratio of particles of different volumes is first calculated based on the density uniformity of the spherical water flow particles. Then, the particle velocity is decomposed into a normal component in the direction of the collision normal and a tangential component perpendicular to the normal. The tangential velocity remains unchanged. The normal velocity after the collision is calculated by combining the restitution coefficient and the law of conservation of momentum. Finally, the complete motion velocity of the particles is synthesized.

[0047] In one possible implementation, when calculating the motion parameters after the collision of spherical water flow particles with an ocean profiling buoy, all capsule-shaped colliding bodies are first treated as a rigid whole and their physical parameters such as center of mass and moment of inertia are calculated. Then, the collision geometry information such as the collision normal, penetration depth, and contact point is calculated. Subsequently, the collision relative velocity, effective mass, and normal impulse are calculated. Finally, the velocity of the spherical water flow particles and the velocity and angular velocity of the ocean profiling buoy as a whole are updated synchronously.

[0048] In one possible implementation, when the ocean profile observation buoy is in a floating state, the coordinates of the center of buoyancy are first calculated using the volume of the fluid it displaces as the integration domain. Then, based on the relative position of the center of gravity and the center of buoyancy and the buoy's tilt angle, the floating righting torque that restores the buoy to a normal state is calculated. The floating righting torque is one of the forces that update the buoy's motion parameters.

[0049] In one possible implementation, when the ocean profiling buoy is in a floating state, the forces used to update its motion parameters include the buoy's own weight, buoyancy calculated based on the volume of displaced water, the resultant collision force generated by spherical water flow particles, and the floating righting moment.

[0050] The specific process for handling the state above water is as follows: First, the analysis is performed on the ocean profile observation buoy located above the water. The ocean profile observation buoy is subject to its own gravity on the water surface. There is a gravity applied to the ocean profile observation buoy, and the gravity it experiences is G.

[0051] It is located above the water surface, displacing a certain volume of water, and is thus subject to buoyancy. The formula for the buoyancy force is: ,in The density of water, It is the acceleration due to gravity. This refers to the volume of water displaced.

[0052] In addition to the effects of gravity and buoyancy, ocean profiling buoys are also excited by external spherical water current particles. The spherical water current particles furthest from the buoy, under this external excitation, generate waves with varying patterns. These waves, through interactions between themselves, transmit forces to the buoy, causing changes in its motion. The radius of the first layer of spherical water current particles closest to the buoy is... Its quality is The current speed is (That is, the original velocity vector of the first layer of spherical water particles). The radius of the second layer of spherical water particles is... Its quality is The current speed is Both have the same density, and their mass formulas are respectively... Therefore in, The mass of the first layer of spherical water particles. The mass of the second layer of spherical water particles. The density of spherical water flow particles (the density of spherical water flow particles is the same in both layers). R is the radius of the first layer of spherical water flow particles (i.e., the basic radius), kR is the radius of the second layer of spherical water flow particles (which is k times the radius R of the first layer of particles), and k is the expansion coefficient.

[0053] Since the collision occurs on the line connecting the centers of the two spheres, the direction vector of the collision normal is: Where n is the unit normal vector of the collision. This represents the coordinate vector of the center position of the first layer of spherical water particles. This represents the coordinate vector of the center position of the second layer of spherical water particles. The Euclidean distance is the distance between the centers of the first and second layer of spherical water flow particles.

[0054] The collision occurs along the line connecting the centers of the spheres. Only the normal velocity component changes, while the tangential velocity component remains unchanged. Therefore, each velocity is decomposed into a normal component and a tangential component. is the original velocity vector (three-dimensional vector) of the first layer of spherical water flow particles, which is the overall velocity of the particle before the collision; n is the unit normal vector (three-dimensional unit vector) of the collision between the two particles. Let be the normal velocity of the first layer of spherical water particles. The normal velocity of the second layer of spherical water particles. The tangential velocity of the first layer of spherical water particles is... The tangential velocity of the particles in the second layer of spherical water flow (normal velocity is the projection of the particle velocity vector onto the collision normal direction, a scalar representing the magnitude of the velocity along the normal direction; tangential velocity is the component of the particle velocity vector perpendicular to the collision normal direction, a vector). Relative normal velocity before collision. : The coefficient of restitution, e, is defined as the negative of the ratio of the normal component of the relative velocity after the collision to that before the collision. in, This represents the normal velocity of the first layer of spherical water particles after the collision. Let be the normal velocity of the second layer of spherical water particles after the collision, i.e.: Along the direction of the collision normal, the system's momentum is conserved: Solve the simultaneous equations: The solution yields: The tangential velocity remains unchanged after the collision, therefore the tangential velocity of the first layer of spherical water particles is... and the tangential velocity of the first layer of spherical water particles. They are respectively: The complete resultant velocity of the first layer of spherical water particles after the collision And the complete resultant velocity of the second layer of spherical water particles after the collision. They are respectively: The collision calculation for spherical water current particles within the same layer also applies to the above formula, except that the value of k is defined as 1. The transfer of ocean current particles at a distance is also calculated using the above formula after correcting the value of k, thus transmitting the ocean's kinetic trend. Through collision detection, ocean current particles colliding with the ocean profile observation buoy are detected. These ocean current particles transfer their kinetic energy to the ocean profile observation buoy, causing a change in its motion state. To calculate the effect of a single spherical water current particle on the ocean profile observation buoy, since all capsule-shaped colliders are rigidly connected as a whole, all capsule-shaped colliders have the same velocity. Having the same angular velocity The total centroid of the composite model ,in The mass of each capsule-shaped collider, For the center of mass of each capsule-shaped collider, the total moment of inertia tensor is: The total mass of the model is M. The mass of the spherical water particle is... The speed is .

[0055] Calculate the geometric information of the collision: The collision normal n (from the capsule-shaped collider to the surface of the sphere) is: in, It is a very small positive value (e.g.) ).

[0056] Calculate the penetration depth of the collision for: in, The radius of the capsule-shaped collider. Let d be the radius of the spherical water flow particle, and d be the shortest distance from the center of the spherical water flow particle to the axis of the capsule-shaped collider, where d is the point of impact. Approximately: The position vector of the contact point relative to the total centroid of the composite model for: in, For the point of collision contact, This is the overall centroid of the composite model.

[0057] The velocity of the capsule-shaped collider at the point of contact for: in, Let be the translational velocity vector of the center of mass of the capsule-shaped collider; The angular velocity vector of the capsule-shaped collider; Let be the position vector of the contact point relative to the center of mass of the capsule.

[0058] Normal relative velocity for: in, Let be the velocity vector of the spherical water particle, and n be the collision unit normal vector. The velocity of the capsule-shaped collider at the point of contact is given.

[0059] The reciprocal of the mass of the ocean profiling buoy model is: in, For the effective mass of the collision, Let M be the mass of the spherical water particle and M be the mass of the ocean profiling buoy. Let n be the position vector of the contact point relative to the buoy's center of mass, and n be the collision unit normal vector. Let be the moment of inertia of the buoy about its center of mass.

[0060] The normal impulse j of the collision is: Where e is the coefficient of restitution. The normal relative velocity before the collision. The effective mass of the collision.

[0061] The velocity of the ball after the collision for: in, Let be the velocity vector of the spherical water particle before the collision, and j be the normal impulse of the collision. Let n be the mass of the spherical water particle, and n be the collision unit normal vector.

[0062] Velocity of the ocean profile observation buoy model after the collision and angular velocity They are respectively: in, Let M be the translational velocity vector of the buoy's center of mass before the collision, and M be the mass of the buoy. Let be the angular velocity vector of the buoy before the collision. Let be the inverse matrix of the buoy's moment of inertia about its center of mass. Let be the position vector of the contact point relative to the buoy's center of mass, and j be the normal impulse of the collision. The collision unit normal vector; The updated velocity values ​​for the ocean profile observation buoy model. This provides the updated angular velocity values ​​for the ocean profile observation buoy model. Based on collision detection and motion interactions in each frame, the relevant motion parameters of the ocean profile observation buoy model and the ocean current particle model are updated.

[0063] In each frame of the execution process, the collisions and motions between spherical water flow particles are calculated from far to near. Then, the forces exerted on the ocean profile observation buoy by all spherical water flow particles that collide with it are calculated, and the motion state of the ocean profile observation buoy in the next frame is estimated accordingly.

[0064] The gravity of an ocean profiling buoy is greater than its buoyancy, so it will gradually move downwards in the water until its gravity equals its buoyancy, at which point it will stop moving. However, during its descent from the water surface, its attitude changes due to the excitation of spherical water particles or tilting during placement. When its center of gravity is not directly above its center of buoyancy, the buoy will generate a righting moment, causing it to return to its normal position. (The center of buoyancy of an ocean profiling buoy is...) The formula for calculating the three-dimensional coordinates of the center of buoyancy is: The integration domain is the volume of fluid displaced by the object, where... and The coordinate components of the center of buoyancy along the X-axis (horizontal), Y-axis (horizontal), and Z-axis (vertical) in a three-dimensional virtual ocean rectangular coordinate system represent the centroid spatial location of the volume of seawater displaced by the buoy. This provides a core geometric reference for subsequent calculations of the righting moment and updates to the buoy's attitude motion parameters. x1, y1, and z1 represent the infinitesimal elements representing the volume of seawater displaced by the buoy. The spatial coordinate components on the X, Y, and Z axes in a three-dimensional virtual ocean rectangular coordinate system, i.e., the position coordinates of the infinitesimal volume. This means that by performing a triple integral over the volume domain of the seawater displaced by the buoy, we obtain the total volume of the seawater displaced by the buoy (the volume of the part of the buoy submerged in water when it is above water, and the total volume of the buoy when it is underwater). , and These are the first moments of the volume of seawater displaced by the buoy in the X, Y, and Z axes, respectively. They are the integrals of the product of the infinitesimal element's coordinates and its volume over the entire displaced volume domain, used to calculate the centroid (center of buoyancy) coordinates of the displaced volume using a weighted calculation. The above formula, by calculating the centroid of the displaced seawater volume, accurately reflects the equivalent point of application of the buoyant force. These are core geometric parameters for analyzing the buoy's force balance, calculating the tilting and righting moment, and simulating six-degree-of-freedom motion, ensuring the physical accuracy and rigor of the buoy motion simulation.

[0065] Its tilting state is as follows Figure 4 As shown, g is the center of gravity of the ocean profiling buoy, and b is the center of buoyancy of the ocean profiling buoy. It is the new position of the floating center. The intersection of the vertical line and the central axis of the ocean profile observation buoy. The angle between the vertical line of the central axis of the ocean profile observation buoy and the horizontal plane.

[0066] A restoring torque M will be generated in this state. 水上 The calculation formula is as follows: Where M is the mass of the ocean profiling buoy, and g is the acceleration due to gravity. This refers to the buoy's tilt height, which is the distance between the center of gravity and the tilt center. The angle of inclination of the buoy relative to the vertical direction.

[0067] When calculating the motion state of an ocean profile observation buoy at the next moment, in addition to its motion state at the previous moment, the external excitation it currently experiences must also be considered. The external excitations mainly include: its own gravity, buoyancy, the resultant force formed by spherical water flow particles, and its own righting torque. Based on this, the spatial state of the ocean profile observation buoy at the next moment can be calculated.

[0068] In one possible implementation, when the ocean profile observation buoy is in the water, the buoyancy is calculated based on the volume of the ocean profile observation buoy, and the calculation process for the collision force between spherical water flow particles and the ocean profile observation buoy is the same as when it is in the water.

[0069] The calculation of buoyancy and collision force of the buoy in the water state of the ocean profile observation buoy is consistent with the calculation process of the buoy in the surface state. This not only closely matches the real physical conditions when the buoy is fully submerged in seawater, ensuring the physical accuracy of the buoyancy calculation, but also unifies the collision force calculation logic above and below water, avoiding redundant algorithm design, reducing the complexity and computational redundancy of the simulation implementation, and ensuring the physical continuity and parameter consistency of the buoy in the switching between surface and underwater states and in the motion simulation process, thereby improving the operating efficiency of small-scale simulation and the overall stability of motion simulation.

[0070] In one possible implementation, when the ocean profile observation buoy is in the water, the underwater righting moment in three spatial directions is calculated based on the relative position of the center of gravity and the center of buoyancy and the tilt angle of the buoy in different directions. The calculation rules for the righting moment in each direction are consistent, only the values ​​of the tilt angles are different.

[0071] The underwater righting moment is calculated in three spatial directions based on the relative position of the center of gravity and the center of buoyancy, with only the tilt angle differing in each direction and the calculation rules being consistent. This approach can accurately match the real physical condition of ocean profile observation buoys tilting in multiple directions in underwater three-dimensional space, fully restore the motion characteristics of the buoy's underwater attitude self-righting, and improve the physical fidelity of the six-degree-of-freedom motion simulation. It can also simplify the algorithm implementation logic of the righting moment, avoid the complexity and computational redundancy caused by multiple rules, ensure the efficiency of simulation calculation, and keep the attitude correction simulation of the buoy above and below water consistent and consistent, ensuring the stability and accuracy of small-scale real-time motion simulation.

[0072] In one possible implementation, when the ocean profiling buoy is in the water, the forces that calculate its motion parameters include the buoy's own weight, underwater buoyancy calculated by volume, the resultant force of collisions generated by spherical water flow particles, and underwater righting moments in three directions. The change in angular velocity is then calculated based on the underwater righting moments to update the motion state of the ocean profiling buoy.

[0073] When an ocean profiling buoy is completely submerged, its weight remains the same as described above. However, due to the increased volume of water displaced, its buoyancy increases, although the calculation formula remains unchanged. The calculation formula for the impact of ocean current particles on the buoy also remains unchanged, but the righting moment it experiences in the water changes, and its state in the water is as follows: Figure 5 As shown, the righting torque M in a certain direction under this state 水下 for: Where B is the buoyancy force acting on the buoy. Let θ be the distance between the center of buoyancy and the center of gravity, and let θ be the tilt angle of the buoy relative to the vertical direction. The above formula uses the tilt angle around a certain coordinate axis as an example to illustrate the calculation method of the righting moment. The righting moments of the buoy around the other two orthogonal coordinate axes in three-dimensional space can be calculated using the same formula, simply by replacing the tilt angle in the formula with the tilt angle of the corresponding coordinate axis direction. Thus, the righting moments in three directions are calculated. Furthermore, the change in angular velocity caused by the current righting moment is calculated, updating the current state information of the ocean profile observation buoy.

[0074] This application mainly calculates four forces acting on an ocean profile observation buoy, including gravity, buoyancy, the collision force of spherical water particles, and its own righting torque. In each frame, the ocean profile observation buoy undergoes motion changes under the action of these four forces. Through the calculation and simulation of each frame, the motion simulation of the ocean profile observation buoy is realized.

[0075] The virtual model of the ocean profile observation buoy established using this method has multiple functions: 1. Simulating six-degree-of-freedom motion under different sea conditions to verify the stability of the design and optimize the structural design; 2. Simulating the process of launching the buoy into the water from a ship, predicting the possibility of collision with the mother ship, and optimizing the launching scheme and launch angle; 3. Predicting the buoy's drift trajectory by combining real-time / forecasted ocean current field data; 4. Predicting the buoy's survival probability using the model after a typhoon or severe sea condition forecast, providing decision support for whether to take protective measures.

[0076] In one possible implementation, each time S1 to S3 is executed, the collision and motion parameters of the spherical water flow particles that are far from the ocean profile observation buoy are calculated first, in order of distance from far to near. Then, the force of the colliding spherical water flow particles that are close to the ocean profile observation buoy is calculated and the motion state of the ocean profile observation buoy is updated.

[0077] In this embodiment, frames S1 to S3 are continuously executed in a loop, and the collision and motion parameter calculation of spherical water flow particles are completed first in order from far to near, and then the buoy motion state is updated. This perfectly matches the real physical law of the gradual transmission of ocean current force from far to near, ensuring that the temporal logic of the motion of spherical water flow particles and the force response of the buoy is consistent, and accurately restoring the actual physical process of ocean current acting on the buoy. At the same time, the orderly calculation order can avoid conflicts between particle and buoy motion parameter updates, ensuring the stability and accuracy of simulation calculation. The continuous frame state update realizes the smooth and coherent simulation of buoy motion, meets the real-time interactive requirements of small-scale virtual simulation, and greatly improves the physical fidelity and operational reliability of motion simulation.

[0078] In this context, "far" and "near" refer to the center of gravity or overall outline of the ocean profile observation buoy. Specifically, spherical current particles farther from the buoy's center of gravity are considered far-end particles, while those closer are considered near-end particles. During collision detection and motion parameter updates for each frame, the self-collisions between far-end particles and their motion state updates are calculated first, then progressively moving towards the near-end particles. Finally, the collisions and force transfer between near-end particles and the ocean profile observation buoy are calculated. This sequence follows the physical law of the gradual transfer of ocean current forces from far to near; that is, external ocean currents first affect far-end particles, which then transfer momentum to near-end particles through inter-particle collisions, and the near-end particles then transfer the force to the buoy itself.

[0079] This invention constructs a rigid body collision model for a buoy based on an integrated capsule-shaped collider, a particle flow collision model based on adaptive radius spherical water flow particles, and a spherical region for selecting collision detection objects. It establishes a simulation framework for particle flow, adaptive collision surfaces, and rigid body motion, deeply integrating the flexibility and intuitiveness of particle systems with the physical rigor of rigid body dynamics. Using the spherical water flow particle system as a physical interaction actuator, it achieves intuitive and visualized physical control of the buoy's motion process. By regionalizing the volume of spherical water flow particles according to their distance from the buoy, and combining this with collision detection region selection, the computational load for collision detection and motion interaction is significantly reduced. Ultimately, it provides a virtual testing environment with high physical fidelity, strong real-time interactivity, and extremely low R&D costs for ocean profiling buoys and underwater platforms, while also providing a stable and reliable basic simulation platform for buoy motion simulation, structural verification, and subsequent control algorithm development.

[0080] The foregoing has described specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0081] In the description of the embodiments of the present invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In the embodiments of the present invention, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in the embodiments of the present invention, as well as the features of the different embodiments or examples.

[0082] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of embodiments of the present invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0083] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for establishing a virtual profile buoy motion model at a small scale, characterized in that, Includes the following steps: S1: Establish an ocean collision model, which includes a profile buoy collision model and an ocean current particle collision model. The profile buoy collision model is an ocean profile observation buoy composed of several capsule-shaped collision bodies, and the ocean current particle collision model includes several spherical water current particles. S2: Perform self-collision detection on the spherical water flow particles, and perform collision detection between the ocean profile observation buoy and the spherical water flow particles; S3: The ocean profile observation buoy is in two states in the seawater, namely above water and underwater. The forces acting on the ocean profile observation buoy are calculated. Based on the forces, the motion parameters of the ocean profile observation buoy and the spherical water flow particles are updated synchronously to realize the simulation of the single motion state of the ocean profile observation buoy. The continuous motion simulation of the ocean profile observation buoy is achieved by repeatedly executing S1 to S3 and updating the frames continuously.

2. The method according to claim 1, characterized in that, The number of capsule-shaped impactors is four, and the four capsule-shaped impactors are rigidly connected into an integrated structure, with the outer contour matching the actual outer contour of the ocean profile observation buoy.

3. The method according to claim 1, characterized in that, When constructing the ocean current particle collision model, different particle radii are set according to the distance between the spherical current particles and the ocean profile observation buoy. The particle radius is smaller in the region closer to the ocean profile observation buoy and larger in the region farther away. The first layer of spherical current particles is the layer closest to the ocean profile observation buoy. The radius of the first layer of spherical current particles is the base radius. The direction from the ocean profile observation buoy to the first layer of spherical current particles is taken as the outward direction, and several layers of spherical current particles are formed outward. The radius of the spherical current particles is larger as they move outward. The radius of each layer of spherical current particles is equal to the product of the base radius and the expansion coefficient, and the expansion coefficient is not less than 1.

4. The method according to claim 1, characterized in that, Before performing collision detection between the ocean profile observation buoy and the spherical water flow particles in S2, a spherical detection area is constructed with the center of gravity of the ocean profile observation buoy as the center of the sphere and a set length as the radius. The spherical detection area completely surrounds all capsule-shaped collision bodies, and collision detection is performed only on the spherical water flow particles within the area.

5. The method according to claim 1, characterized in that, The collision detection process between the ocean profile observation buoy and the spherical water flow particle in S2 is as follows: Each capsule-shaped collider is detected by the spherical water flow particle. The nearest point of the line segment from the center of the spherical water flow particle to the center axis of the capsule-shaped collider is calculated. The actual distance from the particle center to the nearest point is then calculated. This distance is compared with the sum of the radii of the capsule-shaped collider and the spherical water flow particle to determine whether a collision has occurred.

6. The method according to claim 1, characterized in that, When the ocean profile observation buoy in S3 is in a state above water, the motion parameters after the collision between spherical water flow particles are updated first, and then the motion parameters after the collision between the spherical water flow particles and the ocean profile observation buoy are updated.

7. The method according to claim 1, characterized in that, When an ocean profile observation buoy is in a floating state, the coordinates of the center of buoyancy are first calculated using the volume of the fluid it displaces as the integration domain. Then, based on the relative position of the center of gravity and the center of buoyancy and the buoy's tilt angle, the floating righting torque that restores the buoy to its normal state is calculated. The floating righting torque is one of the forces that update the buoy's motion parameters.

8. The method according to claim 1, characterized in that, When the ocean profile observation buoy is in the water, the buoyancy is calculated based on the overall volume of the ocean profile observation buoy, and the calculation process for the collision force between spherical water flow particles and the ocean profile observation buoy is the same as when it is in the water.

9. The method according to claim 1, characterized in that, When an ocean profiling buoy is in the water, the underwater righting moment in three spatial directions is calculated based on the relative position of the center of gravity and the center of buoyancy and the tilt angle of the buoy in different directions. The calculation rules for the righting moment in each direction are consistent, only the values ​​of the tilt angles are different.

10. The method according to claim 1, characterized in that, Each time S1 to S3 is executed, the collision and motion parameters of the spherical water flow particles that are far away from the ocean profile observation buoy are calculated first, in order of distance from far to near. Then, the force of the colliding spherical water flow particles that are close to the ocean profile observation buoy is calculated and the motion state of the ocean profile observation buoy is updated.

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