Position dynamics-based gabion net bag throwing virtual drilling method

Abstract

The invention discloses a gabion net bag throwing virtual drilling method based on position dynamics, and relates to the field of flood control and river improvement, data is collected through field investigation, and a virtual geometric model is constructed by using three-dimensional modeling software; on the basis of a position dynamics simulation framework, a particle set and various constraints are adopted, physical modeling is carried out on movement behaviors of stones, ropes and gabion net bags, a multi-layer and multi-area modeling method is provided for the gabion net bags in the hoisting stage of throwing, and the calculation efficiency of interactive simulation is improved; an interaction module for filling stones, binding gabion net bags and controlling throwing is developed, and script writing and peripheral access are completed in a UE environment. According to the method, the immersion and practicability of drilling are enhanced through the virtual reality technology, the skill proficiency of an operator can be remarkably improved, the resource consumption and environmental influence of field drilling are reduced, important technical support is provided for flood control emergency rescue and water and soil conservation engineering, and the method has wide market application prospects.

Description

Technical Field

[0001] The invention relates to the field of flood control and river regulation, and in particular to a virtual drill method for casting a gabion net bag based on position dynamics. Background Art

[0002] As a highly efficient flood prevention and rescue material for water conservancy projects, gabion nets are widely used in riverbank protection and reinforcement, diversion and water diversion projects, and the construction of ecological breakwaters. The nets filled with stones can effectively fix the edge of the riverbank, reduce soil loss, and protect the riverbank from flood erosion. At the same time, when constructing water diversion channels and adjusting the direction of water flow, gabion nets can effectively manage the direction of water flow and ensure the stability and safety of water flow in specific areas. In addition, gabion nets can be used to reinforce the shore when constructing breakwaters on the coast and in rivers.

[0003] Therefore, the effective and accurate use of gabions is crucial to the success of flood prevention, rescue and soil and water conservation. However, the casting of gabions not only requires the operator to master the skills of filling gabions with stones, but also requires the operator to have an accurate grasp of the way of tying the gabions with ropes to ensure the stability of the gabions when they are hoisted. In addition, the timing of the casting should also be well controlled. Although the traditional field casting drill method can provide a certain degree of operating experience, it is often limited by its long time, high cost and possible impact on the environment.

[0004] With the advancement of technology, virtual emergency drills have begun to be used in the field of emergency drills. By building realistic disaster scenes in virtual environments and simulating emergency rescue operations, emergency personnel can effectively improve the response speed and efficiency in actual operations. Building a realistic operating space in a virtual drill environment involves the interaction of rigid bodies and obstacles, as well as the dynamic simulation of various deformable objects such as gabions and ropes. The physical simulation modeling of these objects is crucial to enhancing the realism and interactivity of virtual scenes, and puts higher requirements on the real-time and accuracy of simulation technology. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a virtual drill method for casting gabion nets based on position dynamics, which solves the time and resource consumption problems in existing field drill methods and improves the quality and efficiency of drills.

[0006] To achieve the above object, the present invention provides a virtual drill method for casting a gabion net bag based on position dynamics, comprising the following steps:

[0007] Step S1: collect ground object data information through field survey of water conservancy project buildings, and construct a virtual geometric model of the ground object using 3D modeling software based on the collected ground object data information;

[0008] Step S2: Based on the position dynamics simulation framework PBD, the gabion net throwing process is physically modeled, and the behavior and deformation of stones, ropes and gabion nets are simulated by using particle sets and multiple constraints;

[0009] Step S3: construct a stone filling interactive processing module, a gabion net binding interactive processing module and a casting control interactive processing module based on the UE5 editor to realize interactive operations.

[0010] Preferably, in step S2, the following steps are specifically included:

[0011] Step S21: discretizing the geometric models of the three materials, stone, rope and gabion net bag, into a particle set. The stone is discretized by the direct scatter sampling method, and the particles are evenly distributed according to the area to obtain the stone particle set; the rope is discretized by the particle linearization distribution method to obtain the rope particle set; the gabion net bag is discretized by the mesh structure distribution method, and the particle points are arranged on the adjacent common edges of the grid to obtain the gabion net bag particle set;

[0012] Step S22: Apply collision constraints to the stone particle set obtained in step S21, apply bending constraints and distance constraints to the rope particle set, apply a hybrid scheme of distance constraints and shape matching constraints to the gabion net bag particle set to apply elastic deformation, and use the extended shape matching scheme to apply plastic deformation to the gabion net bag.

[0013] Preferably, in the hoisting stage of casting, a multi-level and multi-region modeling method is adopted for the gabion net bag according to the structure of the gabion net bag and the action position of the rope;

[0014] The multi-level design is based on the structural characteristics of the gabion net bag, which is made of two layers of wire mesh sewn together. The gabion net bag is divided into an upper layer and a lower layer after being hoisted.

[0015] The multi-zone design is based on the rope binding position, dividing the gabion mesh into three areas: area one, area two and area three.

[0016] Preferably, combined with the deformation characteristics of different areas and layers when the gabion net is hoisted, the specific processing methods are as follows:

[0017] For the upper area 1 and area 3, elastic deformation occurs due to the tension of the rope and its own gravity. The elastic scheme of distance constraint and shape matching, as well as collision constraint, is used to describe its deformation characteristics.

[0018] For the upper area 2, since it is not subjected to stress or only slightly deformed, collision constraint is used as rigid treatment;

[0019] For the lower layer, areas 1, 2 and 3 undergo elastic and plastic deformations due to the tension of the rope and the gravity of the rocks. The deformation characteristics are described using distance constraints, elastic deformation of shape matching constraints, extended plastic deformation, and collision constraints.

[0020] Preferably, in step S2, the fixed interval between the particles of the rope is set to 15 cm, a high-performance computing shader is written in the particle system of the Unreal Engine using a high-level shading language, and parallel computing is performed through the GPU to complete the deformation simulation modeling of the material; the stones are rendered using a mesh renderer, and the ropes and gabion nets are rendered using a strip renderer.

[0021] Preferably, in the stone loading interaction module of step S3, the user selects and moves the stone in the virtual environment through the pointer of the VR handle. The system provides a stone position detection function, indicates the correct placement position through visual feedback, and provides auditory feedback and tactile feedback by means of sound signals and handle vibration, guiding the user to correctly complete the stone placement process;

[0022] In the interactive module for tying gabion nets, users use the VR handle to grab, stretch and wrap the ropes to tie the ropes to the gabion nets. Through the collision detection box and floating text, the system provides the correct bundling position instructions, and guides users to correctly complete the gabion net tying process through vibration feedback and sound prompts.

[0023] Control the throwing interaction module and design a dual-role interaction mode. Role one is responsible for crane control operations, and role two is responsible for dangerous situation observation and command initiation. The system uses AI assistance to achieve collaborative cooperation between roles. When role one selects an operation, role two automatically switches to AI control mode, and a single person completes the entire process of the virtual drill simulation.

[0024] Therefore, the present invention adopts the above-mentioned gabion net bag throwing virtual drill method based on position dynamics, which has the following beneficial effects:

[0025] (1) The present invention uses PBD to simulate the physical behavior of gabion nets during the casting process, including the interaction and dynamic deformation of stones, ropes and gabion nets, thereby improving the stability and real-time performance of the simulation. Virtual reality technology is used to develop a set of interactive operation interfaces, allowing users to perform gabion net loading, bundling and casting operations in a virtual environment, thereby enhancing the immersion and practicality of the drill.

[0026] (2) The present invention adopts a multi-level and multi-region gabion net physical modeling method, which can adjust the simulation accuracy and processing complexity according to the operational requirements and physical characteristics of different stages, especially the physical behavior simulation during the gabion net filling, lifting and throwing process, and effectively capture the object behavior and deformation at different operation stages.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of a virtual training method for casting a gabion net bag based on position dynamics of the present invention;

[0029] Figure 2 This is a schematic diagram of distance constraint in an embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of a shape matching method in an embodiment of the present invention;

[0031] Figure 4 is a schematic diagram of bending constraint in an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of the internal grid ionization of the gabion mesh bag in the embodiment of the present invention;

[0033] Figure 6 1. It is a left view of a multi-layered gabion mesh bag in an embodiment of the present invention;

[0034] Figure 7 1 is a top view of a multi-zone gabion mesh bag in an embodiment of the present invention;

[0035] Figure 8 is an operation flow chart of the interactive module for loading stones in an embodiment of the present invention;

[0036] Fig. 9 is a flowchart of rope binding interaction operations in an embodiment of the present invention;

[0037] Fig.10 It is a flow chart of the steps of controlling the throwing interaction operation in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0039] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0040] The words "include" or "comprises" and the like used in the present invention mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements. The orientation or position relationship indicated by the terms "inside", "outside", "upper", "lower", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention. When the absolute position of the described object changes, the relative position relationship may also change accordingly. In the present invention, unless otherwise clearly specified and limited, the terms "attachment" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Example

[0042] The present invention provides a virtual drill method for casting a gabion net bag based on position dynamics, comprising the following steps:

[0043] Step S1: collect ground object data information through field survey of water conservancy project buildings, and construct a virtual geometric model of the ground object using 3D modeling software based on the collected ground object data information;

[0044] Step S2: Based on the position dynamics simulation framework PBD, the gabion net throwing process is physically modeled, and the behavior and deformation of stones, ropes and gabion nets are simulated by using particle sets and multiple constraints;

[0045] In step S2, the following steps are specifically included:

[0046] Step S21: discretizing the geometric models of the three materials, stone, rope and gabion net bag, into a particle set. The stone is discretized by the direct scatter sampling method, and the particles are evenly distributed according to the area to obtain the stone particle set; the rope is discretized by the particle linearization distribution method to obtain the rope particle set; the gabion net bag is discretized by the mesh structure distribution method, and the particle points are arranged on the common edges of adjacent grids to obtain the gabion net bag particle set;

[0047] Step S22: Apply collision constraints to the stone particle set obtained in step S21, apply bending constraints and distance constraints to the rope particle set, apply a hybrid scheme of distance constraints and shape matching constraints to the gabion net bag particle set to capture elastic deformation, and use the extended shape matching scheme to capture the plastic deformation of the gabion net bag.

[0048] The distance constraint ensures that the fixed distance between points in the model remains unchanged. It is suitable for simulating slender, linear or grid-like structures, such as the mesh structure of gabions and the linear slender structure of ropes. The shape matching constraint can be used to simulate that the overall shape of gabions remains basically unchanged under the action of forces. The distance constraint construction and solution are shown below. The distance constraint expression is as follows Figure 2 shown.

[0049] The idea of ​​a distance constraint is expressed using an equation of the following form:

[0050] C(p1,p2)=|p1-p2|-d=0;

[0051] In the formula, p1 and p2 are the current positions of particles P1 and P2, |p1-p2| represents the current distance between the two vertices, and d is the distance between the vertices when they are stationary. By iteratively solving the distance constraint equation and adjusting the positions of the vertices, the constraints can be gradually satisfied. Then the gradient of the constraint equation at p1 and p2 is obtained:

[0052]

[0053] The final position correction is shown in the following two equations:

[0054]

[0055] In order to ensure that the gabion mesh can correctly undergo elastic deformation under the action of external force, the shape matching method is used to establish the shape matching constraints, such as Figure 3 As shown in the figure, the system is allowed to iteratively solve the shape matching constraints during the simulation process to achieve the deformation of the object without directly calculating the forces acting on the object. The use of shape matching not only improves the efficiency of simulation, but also ensures the accuracy and authenticity of the simulation results.

[0056] In the shape matching method, a set of mass m is used i The initial position is The particles are used as the input of the system, and the initial particle position and the deformed particle position x i Match to obtain the target position g i Next, to solve the target position, we first need to determine the best rigid body transformation, based on the initial position set and the deformation position set x i The corresponding rotation matrix R and translation vector c and is determined by minimizing the following formula:

[0057]

[0058] where w iis the weight of a single particle. The optimal translation vector is given by the center of mass of the initial shape and the center of mass of the deformed shape:

[0059]

[0060] Minimize Item where r i =x i -c and The optimal linear transformation matrix A between the initial shape and the deformed shape is obtained. This transformation is determined by the following formula:

[0061]

[0062] Because A s is symmetric, it does not contain rotation. Therefore, we only need to extract A r The rotation part of the shape matching is obtained by the optimal rotation R, which can be obtained by polar decomposition A r =RS, where S is a symmetric matrix. Finally, the target position is determined by:

[0063]

[0064] in The final position correction is: Δx i =α(g i (t)-x i (t)). where α∈[0,1] is a user-defined stiffness parameter that defines how much the particle is pulled to the target location.

[0065] The elastic constraints of the above shape matching are extended. r Polar decomposition A r =RS, we get a rotation part R and a symmetric part S = R T A r The matrix S represents the deformation in the unrotated reference frame. Therefore, for each region, we can write p The plastic deformation state is stored in S p is initialized to the identity matrix I. Then, we use two parameters c yield and c creep To control the plastic behavior of the material. If the deformation matrix S satisfies the condition ||SI||2>c yield , the plastic deformation state is updated:

[0066] S p ←[I+Δtc creep (SI)]S p ;

[0067] where Δt is the simulation time step, c creep is the creep rate of the material.

[0068] After this update, in order to maintain volume conservation, S p Divide by To maintain the volume. Since this method is extended from shape matching elastic deformation and is not a geometric constraint, it is integrated into the above shape matching method. Specifically, the plastic state S p The reference shape is deformed to integrate during the shape matching process. This is achieved by replacing the elastic deformation in the shape matching method. Definition, Plasticity can be defined by the following condition, where c max Is the threshold of maximum plastic deformation. If the maximum plastic deformation condition is met, update its plastic state using the following.

[0069] S p ←I+c max (S p -I) / ||S p -I||2;

[0070] In the simulation process, it is necessary to use the rope in front of the crane to tie the gabion net bag, and then lift the gabion net bag for throwing. Therefore, in addition to the distance constraint required to simulate the tensile resistance, it is also important to simulate the bending. For this reason, a bilateral bending constraint is added to each pair of adjacent triangles (x1, x3, x2) and (x1, x2, x4). Figure 4 This is a schematic diagram of the bending constraint. The function of this constraint is:

[0071]

[0072] Among them, the stiffness is k bend The scalar φ0 is the initial dihedral angle between the two triangles, and k bend is a global user parameter that defines the bending stiffness of the rope.

[0073] Since the loading of stones and the tying of ropes involve collisions between different objects, we construct two methods here: continuous collision constraints and discrete collision constraints to handle collisions between different objects. Define a ray formed by an object during its movement, which points from the previous position of the movement to the next new position, that is, x i →p i If the ray penetrates the object model, it is necessary to calculate the contact point q between the ray and the model c and the normal vector n at the contact point c , and then perform the continuity collision constraint. The continuity collision constraint belongs to the inequality type, and its constraint equation is expressed as:

[0074] C(p)=(pq c )·n c ;

[0075] For discrete collisions, we need to find the point q on the surface of the collision body that is closest to the new position. s , and calculate the normal vector n of the point s , and then perform collision constraints. The corresponding constraint type is inequality, and its constraint equation can be expressed as:

[0076] C(p)=(pq s )·n s ;

[0077] The gabion net throwing process is divided into three main stages: stone filling, gabion net lifting and throwing.

[0078] During the stone filling stage, the gabion mesh will undergo reversible elastic deformation due to the compression of the stones. As the stones are gradually filled, the shape of the mesh will change accordingly according to the stacking of the stones.

[0079] The lifting stage involves physical modeling of ropes and gabion nets. In this stage, the ropes will be stretched and bent during the dragging process. At the same time, the gabion nets will not only undergo elastic deformation but also plastic deformation due to the gravity of the internal stones and the tension of the ropes. Such deformation is irreversible to a certain extent.

[0080] Finally, in the casting stage, the gabion net and the internal stones will act as a whole and fall under the action of gravity after the force is withdrawn. At this time, the whole can be treated as a rigid body, which simplifies the calculation and improves the system response speed.

[0081] For the above deformation analysis, according to the PBD algorithm process, the overall design and implementation process of the required material physical modeling is as follows:

[0082] 1) Discretize the geometric model into a set of particles. Since the PBD algorithm framework needs to operate on particle points, we need to discretize all models into a set of particle points.

[0083] 2) Apply constraints between particles. For the physical modeling of emergency materials, it is necessary to use the deformation characteristics of the materials and then apply the required constraint equations to the particle collection.

[0084] 3) Simulation process, solution. Based on the first two steps, simulation needs to iteratively solve the constraint equations to obtain the new position and velocity of the particles that meet all the constraint conditions, so as to achieve the characteristic effect of deformation.

[0085] 4) Rendering. This process requires all particles to be constructed into surfaces, making the performance of physical modeling more intuitive and obvious.

[0086] In the stage of discretizing the geometric model into particles, the discretization scheme for each material is shown in Table 1.

[0087] Table 1

[0088]

[0089] In the discretization process of the stone model, considering the high rigidity and relatively simple point-surface distribution characteristics of stones, the direct scattering method is a simple and effective solution for particleization. By evenly distributing particles on the polygonal surface of each stone according to the area ratio, the consistency and uniformity of the particle distribution of the entire model are ensured.

[0090] For ropes, which are long and thin structures, particles are placed evenly along the length of the rope. Each particle represents a portion of the rope and is arranged linearly along the center line of the rope. In order to achieve a balance between rope simulation accuracy and efficiency, the distance between two particles is set to 15cm.

[0091] Gabion net is a mesh structure. We arrange particle points on the common edges of adjacent grids of gabion net. These particle points represent the connection points of the wires in the metal mesh. Figure 5 Particle point placement locations for the internal mesh portion of the structure are shown.

[0092] The key to PBD modeling lies in constraint construction and application. Based on the constraint construction in the above principle, it is then applied to the material model that has been discretized into particles, and appropriate constraints are applied between each particle to make the simulation process deform. Before applying constraints, combined with deformation analysis, the corresponding constraints are constructed according to the deformation characteristics, as shown in Table 2 below.

[0093] Table 2

[0094]

[0095]

[0096] In addition, since the entire casting process is divided into multiple stages, and the rescue materials and operations used in each stage are different, in order to improve the operating efficiency and interactivity of the virtual drill system, for the lifting stage of the gabion net bag, the gabion net bag is affected by its own weight and volume after being filled with stones. When it is lifted, only some areas will be affected by deformation, while some areas will be slightly affected by deformation. The particles in these areas can be treated as rigid bodies. Therefore, a multi-level and multi-area approach is used for modeling in the lifting stage. Different physical modeling is performed for different levels and different areas of the gabion net bag in the lifting stage, which can increase the stability and real-time performance of the simulation.

[0097] During the hoisting stage of casting, a multi-level and multi-region modeling method is adopted for the gabion net bag according to the structure of the gabion net bag and the working position of the rope;

[0098] As for "multi-layer", because the gabion mesh bag can be regarded as two wire mesh sheets sewn together when it is woven, one on top and the other on the bottom to form a bag-like structure, the multi-layer is divided into two layers along this seam. When the filling is completed, the lower layer is placed on the ground and in contact with the ground, and the upper layer faces the sky. As for "multi-area", after the gabion mesh bag is tied up with ropes, the two ropes divide the gabion mesh bag into three areas. As follows Figure 6 and Figure 7 The figure shows the multi-level and multi-area left view and top view of the gabion net bag under the action of two ropes. The upper layer is away from the rope surface when the rope lifts the net bag, that is, facing upwards, and the lower layer is in contact with the rope surface. Area 1, area 2 and area 3 are three areas divided according to the position of the rope tied to the net bag.

[0099] The multi-level design is based on the structural characteristics of the gabion net bag, which is made of two layers of wire mesh sewn together. The gabion net bag is divided into an upper layer and a lower layer after being hoisted.

[0100] The multi-zone design is based on the rope binding position, dividing the gabion mesh into three areas: area one, area two and area three.

[0101] Combined with the deformation characteristics of different areas and layers when the gabion mesh is hoisted, the specific treatment methods are as follows:

[0102] For the upper area 1 and area 3, elastic deformation occurs due to the tension of the rope and its own gravity. The elastic scheme of distance constraint and shape matching, as well as collision constraint, is used to describe its deformation characteristics.

[0103] For the upper area 2, since it is not subjected to stress or only slightly deformed, collision constraint is used as rigid treatment;

[0104] For the lower layer, areas 1, 2 and 3 undergo elastic and plastic deformations due to the tension of ropes and the gravity of rocks. The deformation characteristics are described by using distance constraints, elastic deformation of shape matching constraints and extended plastic deformation, as well as collision constraints.

[0105] The multi-level and multi-regional specific summary table is shown in Table 3.

[0106]

[0107] The PBD method uses a position-based constraint solver to achieve simulation stability and real-time performance by iteratively solving position constraints. PBD simulates the deformation effect after being subjected to force by iteratively adjusting the position of particles. These particles are the discretized points generated by surface sampling of the geometric model.

[0108] The object to be physically modeled is represented by N particles and M constraints. A particle i∈[1,…,N] is represented by a position x i ∈R 3 , speed v i ∈R 3 and mass m i ∈R. The equality or inequality constraints j∈[1,…,M] are expressed in terms of cardinality n j to form, and according to the type of constraint There are different functions, and also use coefficients to control the k j ∈[0…1] represents the stiffness. The result of constraint solving is an estimate of the new position of the node, which satisfies all constraints and is expressed by p i ∈R 3 Indicates that p i is the predicted position, satisfying all constraint functions C j location.

[0109] For all particles i, initialize the properties:

[0110] Simulate the loop, for all particles i, v i ←v i +Δtw i f ext (x i );p i ←x i +Δtv i ; All particles i: Generate collision constraints: (x i →p i );

[0111] Iteration count loop, projection constraints The loop ends and the iterative solver performs an iterative correction of the predicted position to satisfy M interior and M CollExternal constraint: The constraint function is written as C(p+Δp)=0. The following approximate constraint function is used:

[0112]

[0113] The derivative of the N components of the function C with respect to position is written as a vector A scalar value λ is chosen to constrain the direction of the change Δp to maintain the gradient to ensure that they are aligned as follows:

[0114]

[0115] Combining the above two formulas, λ can be solved as follows:

[0116]

[0117] Then the displacement of each node i is obtained as follows:

[0118]

[0119] For all particles i, update the velocity v i ←(p i -x i ) / Δt; Update position x i ←p i ; The position and velocity can be based on the corrected position p i to update.

[0120] The simulation process of substituting three materials into the PBD algorithm is solved. For the particle sets of each model constructed above, their particle states are initialized, including the initial position (constructed according to the discretization method of different materials), the initial velocity (generally 0) and the mass of the particles (in order to simplify the calculation process of the entire framework, the same particle mass is adopted for different model particles). In each time step of the simulation cycle, external forces such as gravity are first applied to all particles, and then the velocity and predicted position of the particles are updated. Next, the constraints constructed by different models in the previous step are iteratively solved, and the predicted position is corrected to meet all the constraints. The specific method is to use the constrained Jacobi solver to solve the position-based constraint equation. Because it has good parallel processing capabilities, it can be calculated with the help of GPU. In the virtual exercise of throwing simulation, the user's interactive operations can be quickly reflected in the simulation results, improving the authenticity of the exercise and the immersion of the virtual exercise. The last step is to update the position and velocity of the particles according to the constraint settlement results to realize the interactive simulation of the dynamic behavior of different materials.

[0121] Finally, in the particle system of UE5, high-performance computing shaders are written using high-level shading languages, and parallel computing is performed through the GPU to solve the above physical modeling process. For the rendering of the three types of emergency materials, the renderer provided by the UE5 particle system is used for rendering, the stones are rendered using the mesh renderer, and the ropes and gabion nets are rendered using the strip renderer.

[0122] In step S2, the fixed interval between rope particles is set to 15 cm, and a high-performance computing shader is written in the particle system of the Unreal Engine using a high-level shading language, and parallel computing is performed through the GPU to complete the deformation simulation modeling of the material; the mesh renderer is used to render the stones, and the strip renderer is used to render the ropes and gabion nets.

[0123] Step S3: Based on the UE5 editor, the interactive processing module for filling stones, the interactive processing module for binding gabion net bags, and the interactive processing module for controlling throwing are constructed to realize interactive operations. In the interactive module for filling stones in step S3, the user selects and moves stones in the virtual environment through the pointer of the VR handle. The system provides a stone position detection function, indicates the correct placement position through visual feedback, and provides auditory feedback and tactile feedback by means of sound signals and handle vibration to guide the user to correctly complete the stone placement process; the system prompts the user to continue to select the next stone for placement to ensure its optimal placement, and indicates the correct placement position through visual feedback (such as the glow of the edge of the stone). The UE5 physics engine is used to physically model the stone. During the placement process, pressure and displacement will be generated on the net bag, and visual and tactile feedback such as sound signals and handle vibration will be provided, so that the user can intuitively perceive the impact and correctness of each placement, ensuring that the behavior of the stone in the virtual net bag is consistent with the real world. Until the entire gabion net bag is filled, the system prompts the user that the net bag is filled. Figure 8 This is the module design operation flow chart.

[0124] In the interactive module for bundling gabion nets, users use the VR handle to grab, stretch and wrap ropes to tie them to the gabion nets. Through the collision detection box and floating text, the system provides the correct bundling position indication, and guides users to correctly complete the gabion net bundling process through vibration feedback and sound prompts. In order to tie the ropes to the correct position of the gabion net, a collision detection box is added to it. When the user drags the two ropes to the quarter area of ​​the edge of the gabion net, the system provides intuitive visual feedback to prompt the user that the ropes have reached the specified position. In addition, floating text is used to guide users on how to correctly wrap and tighten the ropes to ensure the accuracy of the bundling. Once the bundling is completed, the system will confirm the success of the operation or the need for adjustment through vibration feedback and sound prompts. At the same time, dynamic instructions are used to display the nodes where the ropes should be fixed to ensure the maximum stability of the net, providing users with immediate feedback. For example, a confirmation signal will be displayed on the interface when the ropes are tied correctly, and correction prompts will be provided in case of incorrect operations. Fig. 9 It is a flowchart of rope binding interaction operations.

[0125] Control the throwing interaction module and design a dual-role interaction mode. Role one is responsible for crane control operations, and role two is responsible for dangerous situation observation and command initiation. The system uses AI assistance to achieve collaborative cooperation between roles. When role one selects an operation, role two automatically switches to AI control mode, and a single person completes the entire process of the virtual drill simulation.

[0126] The operation process is that character one selects the corresponding character, such as the dangerous situation observation and command initiation character. Character one issues a lifting command after tying the gabion net bag, and then the AI ​​operates the crane to move to the designated position. Afterwards, character one goes to the observation area to determine the timing and position of the throw. When the crane hook is aimed at the target, character one sends a throw command to the AI ​​player to complete the operation. After the throw is completed, choose whether to continue throwing according to the characteristics of the dangerous situation. Fig.10 It is a flow chart of the operation steps of controlling the throwing interaction module.

[0127] Embodiment 2

[0128] This method was applied in the Yuhe Culvert Project of the South-to-North Water Diversion Project, and it has shown significant advantages in practical applications. Through virtual drills, it is possible to quickly simulate multiple casting operations, record and analyze the casting efficiency and accuracy of gabion nets, which is more efficient than traditional on-site drills and significantly reduces time and cost investment. Virtual drills avoid negative impacts on the environment, and through repeated simulation training, the skill level of operators is improved, providing valuable data support and practical experience for flood prevention and rescue.

[0129] This application demonstrates its great potential in the field of flood control and river regulation. It is not only suitable for emergency drills in water conservancy projects, but can also be promoted and applied to other fields that require virtual drills, such as earthquake rescue and fire emergency. By improving the efficiency and effectiveness of drills, this solution provides important technical support for various emergency responses and disaster prevention and mitigation work, and has broad market application prospects.

[0130] Therefore, the present invention adopts the above-mentioned virtual drill method for casting gabion nets based on position dynamics, and enhances the immersion and practicality of the drill through virtual reality technology, which can significantly improve the operator's skill proficiency, reduce the resource consumption and environmental impact of field drills, and provide important technical support for flood prevention and rescue and soil and water conservation projects, and has broad market application prospects.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A virtual drill method for casting a gabion net bag based on position dynamics, characterized in that: The following steps are involved: Step S1: collect ground object data information through field survey of water conservancy project buildings, and construct a virtual geometric model of the ground object using 3D modeling software based on the collected ground object data information; Step S2: Based on the position dynamics simulation framework, the gabion net throwing process is physically modeled, and the behavior and deformation of stones, ropes and gabion nets are simulated by using particle sets and multiple constraints; Step S3: construct a stone filling interactive processing module, a gabion net binding interactive processing module and a casting control interactive processing module based on the UE5 editor to realize interactive operations.

2. A method for virtual training of gabion net throwing based on position dynamics according to claim 1, characterized in that: In step S2, the following steps are specifically included: Step S21: discretizing the geometric models of the three materials, stone, rope and gabion net bag, into a particle set. The stone is discretized by the direct scatter sampling method, and the particles are evenly distributed according to the area to obtain the stone particle set; the rope is discretized by the particle linearization distribution method to obtain the rope particle set; the gabion net bag is discretized by the mesh structure distribution method, and the particle points are arranged on the common edges of adjacent grids to obtain the gabion net bag particle set; Step S22: Apply collision constraints to the stone particle set obtained in step S21, apply bending constraints and distance constraints to the rope particle set, apply a hybrid scheme of distance constraints and shape matching constraints to the gabion net bag particle set to apply elastic deformation, and use the extended shape matching scheme to apply plastic deformation to the gabion net bag.

3. A method for virtual training of gabion net throwing based on position dynamics according to claim 2, characterized in that: During the hoisting stage of casting, a multi-level and multi-region modeling method is adopted for the gabion net bag according to the structure of the gabion net bag and the working position of the rope; The multi-level design is based on the structural characteristics of the gabion net bag, which is made of two layers of wire mesh sewn together. The gabion net bag is divided into an upper layer and a lower layer after being hoisted. The multi-zone design is based on the rope binding position, dividing the gabion mesh into three areas: area one, area two and area three.

4. A method for virtual training of gabion net throwing based on position dynamics according to claim 3, characterized in that: Combined with the deformation characteristics of different areas and layers when the gabion mesh is hoisted, the specific treatment methods are as follows: For the upper area 1 and area 3, elastic deformation occurs due to the tension of the rope and its own gravity. The elastic scheme of distance constraint and shape matching, as well as collision constraint, is used to describe its deformation characteristics. For the upper area 2, since it is not subjected to stress or only slightly deformed, collision constraint is used as rigid treatment; For the lower layer, areas 1, 2 and 3 undergo elastic and plastic deformations due to the tension of the rope and the gravity of the rocks. The deformation characteristics are described using distance constraints, elastic deformation of shape matching constraints, extended plastic deformation, and collision constraints.

5. A method for virtual training of gabion net throwing based on position dynamics according to claim 1, characterized in that: In step S2, the fixed interval between the particles of the rope is set to 15 cm, and a high-performance computing shader is written in the particle system of the Unreal Engine using a high-level shading language, and parallel computing is performed through the GPU to complete the deformation simulation modeling of the material; The stones were rendered using the Mesh Renderer, and the ropes and gabions were rendered using the Ribbon Renderer.

6. A method for virtual training of gabion net throwing based on position dynamics according to claim 1, characterized in that: In the stone loading interaction module of step S3, the user selects and moves stones in the virtual environment through the pointer of the VR handle. The system provides a stone position detection function, indicating the correct placement position through visual feedback, and provides auditory feedback and tactile feedback through sound signals and handle vibration to guide users to correctly complete the stone placement process; In the interactive module for tying gabion nets, users use the VR handle to grab, stretch and wrap the ropes to tie the ropes to the gabion nets. Through the collision detection box and floating text, the system provides the correct bundling position instructions, and guides users to correctly complete the gabion net tying process through vibration feedback and sound prompts. Control the throwing interaction module and design a dual-role interaction mode. Role one is responsible for crane control operations, and role two is responsible for dangerous situation observation and command initiation. The system uses AI assistance to achieve collaborative cooperation between roles. When role one selects an operation, role two automatically switches to AI control mode, and a single person completes the entire process of the virtual drill simulation.

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