An umbrella folding modeling method of a diamond-shaped flexible rope net

Abstract

The application discloses a kind of umbrella-shaped folding modeling methods of diamond flexible rope net, it is related to rope net capture technical field, including the following steps: the folded diamond flexible rope net is divided into multiple layers node group and multiple net ropes, wherein the node group of innermost layer only includes multiple radial nodes, and the rest multiple layers node group includes multiple radial nodes and multiple lap nodes;According to the position of multiple radial nodes and net rope length, the coordinates of multiple radial nodes are calculated;Each layer node group is divided into multiple areas along clockwise, and each area includes two radial nodes;The coordinates of multiple lap nodes are calculated by weighted average of two radial nodes of multiple areas in multiple layers node group respectively;The coordinates of multiple radial nodes and the coordinates of multiple lap nodes are connected by multiple net ropes, and the umbrella-shaped folding model of diamond flexible rope net is constructed.The present application enables researchers to quickly construct the geometric model of the rope net in the folded state, thereby improving the simulation efficiency.

Description

Technical Field

[0001] This invention relates to the field of rope net capture technology, and in particular to a method for modeling the umbrella-shaped folding of a rhomboid flexible rope net. Background Technology

[0002] Flexible rope nets have wide applications in fisheries, aerospace, and protection fields, such as satellite capture and protective nets. Made of woven fiber ropes, flexible rope nets are lightweight, high-strength, and can be folded, stored, and deployed. A flexible interceptor net system uses an interceptor missile to launch a large-sized flexible rope net to capture targets flying within the atmosphere. It mainly consists of the interceptor missile, a structural module, and the flexible rope net. During the capture process, the flexible rope net unfolds, collides with the target, and then retracts. This system is a novel target interception technology, and the size of its defense area (vertical projected area) is a key indicator affecting its defensive effectiveness. Analyzing the defense area of ​​this flexible rope net typically requires dynamic finite element simulation. To complete the finite element analysis and examine the characteristics of flexible rope nets of different sizes, the first step is to establish a parametric flexible rope net folding model.

[0003] However, the shape of the rope net changes drastically before and after folding, and the model becomes extremely complex with increasing folding counts, making parametric modeling difficult. To achieve finite element simulation, existing research often ignores the initial unfolding process of the rope net from its folded state. This method cannot study the entire unfolding process, and the initial unfolded shape selected as the initial state for dynamic simulation is unlikely to correspond to reality, significantly reducing the reliability of the dynamic simulation results. Other studies have established simple flexible rope net folding models, but these models, for ease of creation, have few folds, occupy a large space, cannot be installed in the interceptor missile's structural compartment, and differ significantly from reality. Furthermore, they do not consider parametric modeling, making it impossible to quickly generate models by changing specific parameters such as rope length, hindering comparative studies.

[0004] There is currently little research on parametric modeling methods for complex folded rope nets. In practical applications, researchers mostly skip the dynamic simulation step and directly conduct physical experiments to obtain rope net deployment data. Alternatively, they simply refer to the dynamic simulation results and then conduct physical experiments. Both of these approaches make the research and development of flexible interception net systems difficult, costly, and slow. Summary of the Invention

[0005] This invention provides a method for modeling the umbrella-shaped folding of a rhomboid flexible rope net, which solves the problems of large model space occupation, high difficulty, high cost and slow progress of the rope net model constructed in the prior art.

[0006] This invention provides a method for modeling the umbrella-shaped folding of a rhomboid flexible rope net, comprising the following steps:

[0007] The folded rhomboid flexible rope net is decomposed into multiple layers of node groups and multiple net ropes. The innermost node group includes only multiple radial nodes, while the other multiple layers of node groups include multiple radial nodes and multiple overlapping nodes. The multiple radial nodes of each layer form a hexagon, and the multiple overlapping nodes are located between two adjacent radial nodes.

[0008] Calculate the coordinates of multiple radial nodes based on their positions and the length of the netting.

[0009] Each node group is divided into multiple regions in a clockwise direction, and each region includes two radial nodes;

[0010] The coordinates of multiple overlapping nodes are calculated by weighted averaging of two radial nodes in multiple regions of the multi-layer node group.

[0011] A rhomboid flexible rope net umbrella-shaped folding model is constructed by connecting the coordinates of multiple radial nodes and multiple overlapping nodes with multiple ropes.

[0012] Preferably, calculating the coordinates of multiple radial nodes based on their positions and the length of the net rope includes the following steps:

[0013] Measure the length l of the net rope;

[0014] Obtain the angle α between multiple radial nodes and their corresponding net ropes. k ;

[0015] Obtain the projected distance r of multiple net rope lengths l corresponding to multiple radial nodes in the xoy plane. k and the angle β with the x-axis k , where k is the number of layers;

[0016] Based on length l and included angle α k Projection distance r k and the included angle β k Calculate the coordinates of multiple radial nodes.

[0017] Preferably, the coordinates of multiple radial nodes are calculated using the following formula:

[0018] X k,i =(r k sin(i-1)β k ,r k cos(i-1)β k ,klcosα k ), where k is an odd number;

[0019] X k,i =(r k sin((i-1)β k ),r k cos((i-1)βk ),0),k is an even number

[0020] in,

[0021] r k =klsinα k

[0022]

[0023] In the formula, X k,i Let represent the coordinates of multiple radial nodes, where i is the index of the radial node in each node group, and n is the index of the radial node. k Let be the number of nodes in the k-th layer.

[0024] Preferably, the coordinates of multiple overlapping nodes are calculated using the following formula:

[0025]

[0026] In the formula X k,j Let X be the coordinates of multiple overlapping nodes, p be the region number, j be the overlapping node number of each layer node group, (p-1)k+1 and pk+1 be the numbers of two radial nodes in each region, and X be the coordinates of multiple overlapping nodes. k,(p-1)k+1 and X k,pk+1 The coordinates of two radial nodes in each region of the k-th layer.

[0027] Preferably, the coordinates of multiple radial nodes and multiple overlapping nodes are connected by multiple net ropes, including the following steps:

[0028] Multiple radial node coordinates in each layer are connected to the coordinates of the three nearest arbitrary nodes in the next layer using multiple net ropes.

[0029] Multiple overlapping nodes on each layer are connected to the two nearest nodes on the next layer using multiple net ropes;

[0030] In the outermost node group, an additional node is introduced between any two adjacent nodes, and the coordinates of multiple additional nodes are calculated. The coordinates of multiple arbitrary nodes and the coordinates of additional nodes are then connected end to end by multiple net ropes.

[0031] Preferably, an additional node is introduced between any two adjacent nodes in the outermost node group, and the coordinates of multiple additional nodes are calculated. This specifically includes the following steps:

[0032] Calculate the distance between any two adjacent nodes;

[0033] Calculate the height difference between any two adjacent nodes;

[0034] Calculate the coordinates of the additional nodes based on the distance and height difference.

[0035] Preferably, the coordinates of the additional nodes are calculated using the following formula:

[0036]

[0037] in,

[0038]

[0039] In the formula, X′ m Let be the coordinates of the additional node, and m be the index of any node in the outermost node group. Let be the x-coordinate of the m-th arbitrary node in the outermost node group. Let be the y-coordinate of the m-th arbitrary node in the outermost node group. Let be the z-coordinate of the m-th arbitrary node in the outermost node group. Let be the x-coordinate of the (m+1)th arbitrary node in the outermost node group. The coordinate of the (m+1)th arbitrary node in the outermost node group on the y-axis, and z′ is the height difference between the m-th arbitrary node and the (m+1)th arbitrary node.

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] This invention first simplifies the rope net structure, dividing the folded rhomboid flexible rope net into multiple layers of node groups and multiple net ropes. Then, the coordinates of multiple radial nodes and multiple overlapping nodes are calculated. The coordinates of the multiple radial nodes and multiple overlapping nodes are connected by multiple net ropes to construct an umbrella-shaped folding model of the rhomboid flexible rope net. Using this method, researchers can quickly construct the geometric model of the rope net in a folded state, thereby improving simulation efficiency. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0043] Figure 1 This is a schematic diagram of the deployed state of the rhomboid flexible interception net of the present invention;

[0044] Figure 2 This is a side view of the flexible interception net in its umbrella-shaped folded state according to the present invention;

[0045] Figure 3 This is a flowchart of a method for modeling an umbrella-shaped folding of a rhomboid flexible rope net according to the present invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Reference Figure 3 This invention provides a method for modeling the umbrella-shaped folding of a rhomboid flexible rope net. The flexible rope net is composed of nodes and net ropes. This method first determines the coordinate position of the nodes after folding, and then uses a specific algorithm to connect the nodes with net ropes.

[0048] Specifically, the following steps are included:

[0049] Step 1: Divide the folded diamond flexible rope net into multiple layers of node groups and multiple net ropes. The innermost node group includes only multiple radial nodes, while the other multiple layers of node groups include multiple radial nodes and multiple overlapping nodes.

[0050] Reference Figure 1 Observing the rhomboid flexible rope net, we can see that the entire rope net is composed of rings of nodes from the inside out. The innermost ring is called k=1, and the outermost ring is called k=k. max The radial nodes of a flexible rope net can be represented by the number of turns k and the index i. When k=1, there are a total of six nodes located on the radial rope, called i=1,2,…,6, where the node i=1 is located on the x-axis, and the remaining nodes are arranged clockwise.

[0051] Step 2: Calculate the coordinates of multiple radial nodes based on their positions and the length of the netting.

[0052] Reference Figure 2 In the umbrella-shaped folding case, the size of the node in the z-axis direction depends on the length of the net rope l and the angle α between the net ropes, while the size in the x and y-axis directions depends on the projection r of the net rope length l onto the xoy plane. k And the angle β between the node and the x-axis in the xoy plane. k Based on the above analysis, the node coordinates when k=1 can be written out.

[0053] The linear distance r of the radial rope node from the origin is the projected distance r in the xoy plane. k =klsinα,

[0054] For cycle k=1, the node coordinates are:

[0055] X 1,i=(r1 sin(i-1)β1,r2 cos(i-1)β1,lcosα)

[0056] When k > 1, observation of the flexible rope net reveals that, in addition to nodes on the radial ropes, there are also nodes on the overlapping ropes. For nodes on the radial ropes, when k is odd, the following formula is used for calculation:

[0057] X k,i =(r k sin(i-1)β k ,r k cos(i-1)β k ,kl cosα k )

[0058] When k is even, it is calculated using the following formula:

[0059] X k,i =(r k sin((i-1)β k ),r k cos((i-1)β k ),0)

[0060] In the formula, X k,i Let represent the coordinates of multiple radial nodes, where i is the index of the radial node in each node group, and n is the index of the radial node. k Let be the number of nodes in the k-th layer.

[0061] Step 3: Divide each layer of node groups into multiple regions in a clockwise direction, with each region including two radial nodes;

[0062] For nodes on the overlapping ropes, it can be observed that their x and y coordinates can be obtained by calculating the weighted average of the x and y coordinates of the radial rope nodes in the same loop nearby. The z-direction coordinates are calculated using the same method as the radial rope nodes. Specifically, for the k-th loop, divide it into p = 1, 2, ..., 6 regions in a clockwise direction. Each region consists of overlapping rope nodes on the straight line connecting two radial rope nodes, with the two radial rope node numbers being (p-1)k+1 and pk+1 respectively. The x and y coordinates of the overlapping rope nodes in this region are then the weighted average of the coordinates of the two radial rope nodes in that region. Therefore, the coordinates of the overlapping rope nodes in loops k>1 are:

[0063]

[0064] In the formula X k,j Let X be the coordinates of multiple overlapping nodes, p be the region number, j be the overlapping node number of each layer node group, (p-1)k+1 and pk+1 be the numbers of two radial nodes in each region, and X be the coordinates of multiple overlapping nodes. k,(p-1)k+1 and Xk,pk+1 The coordinates of two radial nodes in each region of the k-th layer.

[0065] Step 4: Connect the coordinates of multiple radial nodes and multiple overlapping nodes with multiple net ropes to construct a rhomboid flexible rope net umbrella-shaped folding model.

[0066] For a square rope net, it is only necessary to connect all nodes to nearby nodes. However, for a diamond-shaped flexible net, some ropes cannot be connected and nodes cannot be repeatedly connected. Therefore, a specific algorithm is required.

[0067] Regarding the connection of the net rope, it was observed that for ropes not on the outer loop, it is not necessary to connect nodes within the same loop. (Reference) Figure 1 It can be seen that there are two connection methods. For radial rope nodes, they connect to the three nodes of the next loop. For overlapping rope nodes, they connect to the two nodes of the next loop, and the labels of the connected nodes are connected end to end.

[0068] Specifically, for a node in the k-th loop, its connection to a node in the (k+1)-th loop falls into two categories: radial rope nodes connect to 3 nodes, and overlapping rope nodes connect to 2 nodes. Furthermore, it can be observed that the node numbers are consecutive; for example, if i=1 in the k-th loop is a radial rope node, it will connect to node i in the (k+1)-th loop. max There are three nodes, i=1, i=2, i=3, i=4, i=5, i=6, i=7, i=8, i=9, i=1, i=1, i=1, i=1, i=2, i=1, i=3, i=1, i=1, i=1, i=1, i=1, i=2, i=1, i=1, i=3, i=1 ...2, i=

[0069] For the outer loop rope, the connection between nodes within the same loop is difficult to handle. As the folding angle α decreases, the length of the closed curve formed by all nodes on the outermost loop of the flexible rope net decreases, resulting in insufficient rope length and difficulty in unfolding the rope net from its folded state. Therefore, direct connection between nodes is not possible. To address this, this method inserts additional nodes between adjacent outer loop rope nodes to form a broken line.

[0070] The outer loop rope is divided into six regions, each representing one side of a hexagonal interception net. On the xoy plane, the position of an additional node depends on the coordinates of its two nearest neighbors and the length of the net rope. After determining the position of the additional point, each node is first connected to the additional point, and then the additional point is connected to the next node.

[0071] The specific calculation method is as follows:

[0072] (1) Calculate the distance a between the two adjacent nodes of the outermost ring of the folded state;

[0073] (2) Calculate the height difference

[0074] (3) The coordinates of the extra point are:

[0075]

[0076] In the formula, X′ m Let be the coordinates of the additional node, and m be the index of any node in the outermost node group. Let be the x-coordinate of the m-th arbitrary node in the outermost node group. Let be the y-coordinate of the m-th arbitrary node in the outermost node group. Let be the z-coordinate of the m-th arbitrary node in the outermost node group. Let be the x-coordinate of the (m+1)th arbitrary node in the outermost node group. The coordinate of the (m+1)th arbitrary node in the outermost node group on the y-axis, and z′ is the height difference between the m-th arbitrary node and the (m+1)th arbitrary node.

[0077] When connecting the wires, first... With X′ m Connect, then connect X′ m and connect.

[0078] In summary, this method can quickly and effectively construct a rhomboid flexible interception net umbrella-shaped folding model. Furthermore, by changing the rope length l, folding angle α, and k... max This allows for changes in the shape of the rope net, enabling parametric modeling.

[0079] The beneficial effects of this method are:

[0080] 1) Improved efficiency and reliability of dynamic simulation: This method allows researchers to quickly construct geometric models of rope nets in a folded state, thereby improving simulation efficiency. This will help reduce the time and manpower costs of the simulation process and improve the accuracy and reliability of the simulation.

[0081] 2) Enhance the research capabilities of flexible interception net systems: By changing the model parameters, flexible rope nets of different sizes and folding degrees can be quickly constructed and simulated, which improves the research depth and breadth of the simulation part of flexible interception net systems, enhances the reliability of simulation results, and provides important references for researchers.

[0082] 3) Reduce research costs and accelerate research progress: Through this method, some physical experiments of the flexible interception network system can be replaced by dynamic simulation. By changing the simulation parameters, the motion of the interception network under different working conditions can be obtained without repeating physical experiments, thus saving research costs and time.

[0083] 4) Inspired Flexible Interception Net Folding Modeling: This method performs parametric modeling of hexagonal rhomboid flexible interception nets in an umbrella-shaped folding configuration, but its approach is quite general. For different mesh shapes, only the net rope connection algorithm needs to be modified. For square or other contoured flexible rope nets, the main modification is to the node coordinates. The method of using two parameters, k and i, to determine a node for different folding configurations, and the approach of calculating node coordinates before connecting them, are also worth considering.

[0084] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0085] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for modeling the umbrella-shaped folding of a rhomboid flexible rope net, characterized in that, Includes the following steps: The folded rhomboid flexible rope net is decomposed into multiple node groups and multiple net ropes. The innermost node group includes only multiple radial nodes, while the other multiple node groups include multiple radial nodes and multiple overlapping nodes. The multiple radial nodes in each layer form a hexagon, and the multiple overlapping nodes are located between two adjacent radial nodes. Calculate the coordinates of multiple radial nodes based on their positions and the length of the netting. Each node group is divided into multiple regions in a clockwise direction, and each region includes two radial nodes; The coordinates of multiple overlapping nodes are calculated by weighted averaging of two radial nodes in multiple regions of the multi-layer node group. A rhomboid flexible rope net umbrella-shaped folding model is constructed by connecting the coordinates of multiple radial nodes and multiple overlapping nodes with multiple ropes.

2. The umbrella-shaped folding modeling method for a rhomboid flexible rope net as described in claim 1, characterized in that, The coordinates of multiple radial nodes are calculated based on their positions and the length of the netting, including the following steps: Measuring the length of the net rope l ; Obtain the angles between multiple radial nodes and their corresponding net ropes. ; Obtain multiple rope lengths corresponding to multiple radial nodes l Projected distance in the xoy plane and the angle with the x-axis ,in Number of floors; According to length l Angle Projection distance and included angle Calculate the coordinates of multiple radial nodes.

3. The umbrella-shaped folding modeling method for a rhomboid flexible rope net as described in claim 2, characterized in that, The coordinates of multiple radial nodes are calculated using the following formula: , It is an odd number; , Even number in, In the formula, The coordinates of multiple radial nodes, This refers to the index of the radial nodes in each node group. n k For the first The number of nodes in a layer.

4. The umbrella-shaped folding modeling method for a rhomboid flexible rope net as described in claim 3, characterized in that, The coordinates of multiple overlapping nodes are calculated using the following formula: In the formula The coordinates of multiple overlapping nodes. For the region number, j This refers to the sequence number of the overlapping nodes in each node group. and The sequence numbers of the two radial nodes in each region. and No. The coordinates of two radial nodes in each region of the layer.

5. The umbrella-shaped folding modeling method for a rhomboid flexible rope net as described in claim 4, characterized in that, Connecting the coordinates of multiple radial nodes and multiple overlapping nodes using multiple netting ropes includes the following steps: Multiple radial node coordinates in each layer are connected to the coordinates of the three nearest arbitrary nodes in the next layer using multiple net ropes. Multiple overlapping nodes on each layer are connected to the two nearest nodes on the next layer using multiple net ropes; In the outermost node group, an additional node is introduced between any two adjacent nodes, and the coordinates of multiple additional nodes are calculated. The coordinates of multiple arbitrary nodes and the coordinates of additional nodes are then connected end to end by multiple net ropes.

6. The umbrella-shaped folding modeling method for a rhomboid flexible rope net as described in claim 5, characterized in that, Introduce additional nodes between any two adjacent nodes in the outermost node group, and calculate the coordinates of multiple additional nodes. This involves the following steps: Calculate the distance between any two adjacent nodes; Calculate the height difference between any two adjacent nodes; Calculate the coordinates of the additional nodes based on the distance and height difference.

7. The umbrella-shaped folding modeling method for a rhomboid flexible rope net as described in claim 5, characterized in that, The coordinates of the additional nodes are calculated using the following formula: in, In the formula, For the coordinates of the additional nodes, m Let be the index of any node in the outermost node group. The outermost node group m The x-coordinates of any node. The outermost node group m The y-coordinates of any node. The outermost node group m The coordinates of any node on the z-axis The outermost node group m+1 The x-coordinates of any node. The outermost node group m+1 The y-coordinates of any node. For the first m The nth arbitrary node and the nth m+1 The height difference between any two nodes.

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