Pedestrian fall disturbance propagation simulation method, storage medium and device

Abstract

The present application relates to a kind of pedestrian fall disturbance propagation simulation method, storage medium and equipment, the method includes the following steps: based on the theory of fluid dynamics, construct considering pedestrian fall disturbance inside crowd disturbance propagation dynamics model;Based on the inside crowd disturbance propagation dynamics model of the crowd, set pedestrian fall disturbance point, carry out personnel intensive place pedestrian fall disturbance propagation simulation, and show simulation result;Wherein, the inside crowd disturbance propagation dynamics model includes crowd flow pressure term, the crowd flow pressure term is based on the pressure coefficient considering pedestrian fall behavior Construction.Compared with prior art, the present application is by the abnormal abstract behavior of pedestrian fall to carry out pressure analysis and dynamics analysis, to numerically accurate, reliable to show behavior-disturbance process, it is important to the safety management of personnel intensive place.

Description

Technical Field

[0001] This invention relates to the field of crowd flow stability analysis technology, and in particular to a pedestrian fall disturbance propagation simulation method, storage medium and device. Background Technology

[0002] In crowded public places, the precursor to disasters such as stampedes is often a state of chaos and disorder among the crowd, with pedestrian falls being a significant contributing factor. Currently, research methods for detecting pedestrian falls in crowded places can be broadly categorized into two types: external sensor-based detection and computer vision-based detection. External sensor-based detection typically involves wearing sensors on the body or placing them in the external environment to collect human motion data. Computer vision-based fall detection methods usually extract image features from pedestrian targets in surveillance videos, setting thresholds or using machine learning methods to determine whether a pedestrian has fallen.

[0003] To date, research on the propagation dynamics of abnormal pedestrian behavior disturbances caused by falls in densely populated areas has several shortcomings: 1) In many cases, pedestrian falls disrupt a point in the crowd's movement area, causing the crowd flow to gradually change from a stable, orderly state to a chaotic, unstable state. Pedestrian falls are a common phenomenon of crowd flow disturbance. Currently, there are few studies on constructing specific disturbance models based on this abstract behavior of pedestrian falls. 2) When moving forward in crowded conditions, there is a certain "pressure" among the crowd, which can be described as the degree of urgency people feel when encountering an emergency, and it affects the subsequent movement of the crowd. Among these, pedestrian pressure, reflecting the pedestrian's state, is one of the important behavioral characteristics. Currently, there is a lack of quantitative discussion and dynamic analysis of the pressure of abnormal pedestrian behavior caused by falls. 3) There is a lack of research on the temporal and spatial propagation patterns of disturbances caused by pedestrian falls in crowded places, as well as the mechanisms by which they affect crowd flow. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art by providing a method, storage medium, and device for quantifying the stress of pedestrian fall behavior and simulating the propagation of pedestrian fall disturbances in an intuitive and objective manner.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for simulating the propagation of pedestrian fall disturbances includes the following steps:

[0007] Based on fluid dynamics theory, a dynamic model of the propagation of disturbances within a crowd that takes into account pedestrian fall disturbances is constructed.

[0008] Based on the dynamic model of disturbance propagation within the crowd, a pedestrian fall disturbance point is set, and a simulation of pedestrian fall disturbance propagation in densely populated areas is conducted, with simulation results displayed.

[0009] The crowd internal disturbance propagation dynamics model includes a crowd flow pressure term, which is constructed based on a pressure coefficient that takes into account pedestrian fall behavior.

[0010] Furthermore, the dynamics model of disturbance propagation within the crowd is constructed based on the AR traffic flow model.

[0011] Furthermore, the stress coefficient considering pedestrian fall behavior is expressed as:

[0012]

[0013] Where γ represents the pressure coefficient, p represents the pedestrian pressure when a pedestrian falls, and F represents the pedestrian's center of mass force.

[0014] Furthermore, the formula for calculating the pedestrian pressure p when a pedestrian falls occurs differs depending on the location within the crowd. Specifically:

[0015] For pedestrian i who falls, the pedestrian pressure p i Represented as:

[0016]

[0017] For pedestrian i-1 behind, the pedestrian pressure p i-1 Represented as:

[0018]

[0019] For pedestrian i+1 ahead, the pedestrian pressure p i+1 Represented as:

[0020]

[0021] Where, subscript b represents rear pressure, subscript f represents front pressure, p0 represents the front or rear pressure when pedestrian i has not fallen, and t s Let t represent the time when pedestrian i falls. e Let k represent the moment when pedestrian i stops falling, and k is the instantaneous decay coefficient.

[0022] Furthermore, the pressure coefficient ranges from 1 to 1.7.

[0023] Furthermore, the crowd flow pressure term is expressed as P = f(ρ, γ, ξ), where ρ represents the crowd density, γ represents the pressure coefficient, and ξ represents the disturbance intensity.

[0024] Furthermore, the simulation results are specifically shown as follows:

[0025] Contour maps are used to depict pedestrian pressure at different locations.

[0026] Furthermore, the contour map includes a planar contour map and a three-dimensional contour map.

[0027] The present invention also provides a computer-readable storage medium including one or more programs executable by one or more processors of an electronic device, the one or more programs including instructions for performing the pedestrian fall disturbance propagation simulation method as described above.

[0028] The present invention also provides an electronic device including one or more processors, a memory, and one or more programs stored in the memory, said one or more programs including instructions for executing the pedestrian fall disturbance propagation simulation method as described above.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) Currently, there is a lack of discussion on the pressure quantification and dynamic analysis of abnormal pedestrian fall behavior. This invention proposes a pressure dynamic model of pedestrian fall behavior, analyzes the entire process of pedestrian fall behavior, proposes a pressure coefficient of pedestrian fall behavior, shows the change of disturbance over time, and verifies that behavioral characteristics such as pressure are anisotropic due to inconsistent speeds. It can intuitively and reliably simulate the propagation of pedestrian falls in crowded places.

[0031] (2) This invention studies the propagation law of disturbances caused by pedestrian falls in crowded places in time and space. Based on the abnormal behavior propagation of pedestrian falls, it deeply analyzes the impact mechanism of local disturbances in densely populated public places on the overall crowd flow, which is of great significance for crowd control. Attached Figure Description

[0032] Figure 1 This is a schematic flowchart of the method of the present invention;

[0033] Figure 2 This is a schematic diagram illustrating the fall of the present invention;

[0034] Figure 3 In the schematic diagram of the pressure characteristics of a pedestrian falling according to the present invention, (3a) represents the pressure change of pedestrian i, (3b) represents the pressure change of pedestrian i-1, and (3c) represents the pressure change of pedestrian i+1;

[0035] Figure 4 This is a schematic diagram illustrating the propagation of the fall behavior disturbance according to the present invention;

[0036] Figure 5The diagrams show the crowd pressure distribution during the fall behavior of the present invention, wherein (5a) is the crowd pressure distribution at time t = 3.0s and (5b) is the crowd pressure distribution at time t = 5.0s. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0038] Example 1

[0039] like Figure 1 As shown, this embodiment provides a simulation method for pedestrian fall disturbance propagation, including the following steps: S1, based on fluid dynamics theory, constructing a dynamic model of pedestrian fall disturbance propagation within a crowd; S2, based on the dynamic model of pedestrian fall disturbance propagation, setting pedestrian fall disturbance points, and conducting simulation of pedestrian fall disturbance propagation in densely populated areas; S3, displaying the simulation results; wherein, the dynamic model of pedestrian fall disturbance propagation includes a crowd flow pressure term, which is constructed based on a pressure coefficient considering pedestrian fall behavior. The dynamic model of pedestrian fall disturbance propagation is constructed based on the AR traffic flow model. This method considers the activity characteristics of pedestrian fall disturbance, quantifies and dynamically analyzes the pressure during the propagation process of disturbance in dense crowds, and more reliably simulates the propagation dynamics of pedestrian fall behavior disturbance, thereby providing a basis for crowd safety management.

[0040] 1. A pressure dynamics model for pedestrian falls.

[0041] By analyzing the pressure characteristics of pedestrians falling, a pressure dynamic model of pedestrian falls is obtained.

[0042] Pressure dynamics analysis: such as Figure 2 As shown, assuming the movement of pedestrians is on a one-dimensional plane, and the pedestrians are labeled as i-1, i, i+1, when the middle pedestrian i falls, it will affect the pedestrians in front and behind, which means that the abnormal behavior has been disturbed and propagated.

[0043] During movement, a pedestrian is squeezed by pedestrians in front and behind, resulting in a rearward pressure p. back and forward pressure p front The time of the fall is recorded as t. s The entire fall process includes a short period of sustained movement; the pressure changes for the three pedestrians are as follows: Figure 2 As shown.

[0044] For pedestrian i, when a fall occurs, its velocity drops sharply in the forward direction, while pedestrians behind it still have a forward momentum. Therefore, the rear pressure p of pedestrian i is... back (corresponding to p in the diagram) i,b The pressure p will suddenly increase and then decrease to a small, stable value. Because of limited visibility, pedestrians ahead will continue moving forward, thus reducing the forward pressure p. front (corresponding to p in the diagram) i,f The pressure becomes zero. For pedestrian i-1 behind, the pressure behind them remains unchanged, while the pressure in front of them and the pressure behind them are interaction forces, i.e., they remain consistent. For pedestrian i+1 in front, the pressure in front of them remains unchanged, while the pressure behind them and the pressure in front of them are interaction forces, i.e., they remain consistent.

[0045] Therefore, the pressure dynamics model for a pedestrian falling is as follows:

[0046] like Figure 3 As shown in (3a), for pedestrian i:

[0047]

[0048] Here, since the direction of motion is given, the pressure p is taken as a scalar. k is the instantaneous attenuation coefficient. Superimposing the forces acting on the pedestrian's front and rear, it can be seen that when a fall occurs, the total pressure on pedestrian i will be at t. s The timeframe drops sharply, then rises rapidly in an exponential manner, and finally returns to t. e It decays over time to a stable value.

[0049] like Figure 3 As shown in (3b), for pedestrian i-1 behind:

[0050]

[0051] The combined forces acting on the front and rear of the pedestrian will cause the total pressure on pedestrian i-1 to be at t. s The time increases rapidly in an exponential manner, and finally returns to t. e As the pressure decays to a stable value, the pressure will eventually be less than the pressure at the initial moment. This can be understood as the pedestrian behind intentionally maintaining a certain squeezing distance after the fall.

[0052] like Figure 3 As shown in (3c), for pedestrian i+1 in front:

[0053]

[0054] The combined forces acting on the front and back of the pedestrian will cause the total pressure on pedestrian i+1 to be at t. s It decreases over time, then stabilizes at a constant value.

[0055] 2. Construct a dynamic model of the propagation of disturbances within a crowd that takes into account the disturbances caused by falling behavior.

[0056] Any disturbance in a dynamic crowd flow will propagate dynamically to varying degrees. Fluid mechanics and pedestrian flow share certain similarities. Based on the assumption of a continuous medium, the continuity equations of fluid mechanics can be used to describe the motion characteristics of pedestrian flow. Therefore, a dynamic model of the internal disturbance propagation of pedestrian fall behavior is proposed based on fluid dynamics theory.

[0057] In 2000, A.Aw and M. Rascle proposed a flow-based crowd dynamics model. This embodiment refers to the pressure term form of the AR traffic flow model, establishes a two-dimensional pressure term for crowd flow under pedestrian fall behavior based on the traffic flow model, and constructs an internal disturbance propagation dynamics model for pedestrian fall behavior based on the pressure dynamics model of pedestrian fall.

[0058] In this embodiment, the crowd flow pressure term under fall behavior is established as shown in equation (4):

[0059] P=f(ρ,γ,ξ) (4)

[0060] Where ρ is the population density, γ represents the pressure coefficient, and ξ represents the disturbance intensity.

[0061] Define the pressure coefficient γ as:

[0062]

[0063] The pressure coefficient γ is the ratio of pedestrian pressure p to pedestrian centripetal force F. Pressure represents the external force exerted on a pedestrian per unit area. The pressure dynamics model of abnormal fall behavior is referenced in equations (1)-(3). Centripetal force is the internal force driving pedestrian movement. When p>F, the compression exerted on the pedestrian is greater than their own controllable force, making them prone to unsafe events. According to research on pedestrian fall behavior, the value of γ ranges from (1, 1.7).

[0064] Define the disturbance intensity ξ as:

[0065]

[0066] When an abnormal pedestrian fall is detected, the point (a, b) is determined as the disturbance point, with an initial disturbance amount ξ0. The disturbance is random, and its intensity reflects the disturbance decay law within the crowd, exhibiting an exponential power decay function characteristic. That is, the disturbance intensity is greatest at the disturbance point, and decays exponentially with respect to the surrounding crowd. Therefore, the disturbance intensity of the crowd at (x, y) under the influence of random disturbance within the crowd is shown in equation (6). Here, t represents the duration of the disturbance.

[0067] Therefore, the two-dimensional pressure terms of crowd flow under fall behavior are as shown in equations (7) and (8):

[0068]

[0069]

[0070] Among them, P h and P l These represent the horizontal and vertical pressure terms, respectively. The pressure term is a modified form of the velocity gradient term and is not a true unit of pressure.

[0071] Finally, the internal perturbation propagation dynamics model of crowd fall behavior is expressed as:

[0072]

[0073]

[0074]

[0075] Where v and u represent the horizontal and vertical velocities, respectively, V eh and V el Let represent the equilibrium velocities in the horizontal and vertical directions, respectively, and τ be the relaxation factor.

[0076] 3. Simulation demonstration.

[0077] This embodiment uses contour maps to describe pedestrian pressure at different locations, thereby showcasing the simulation results. Specifically, the contour maps include planar contour maps and three-dimensional contour maps.

[0078] In this embodiment, based on literature summaries, a pressure of 6200N for 15 seconds will cause suffocation due to crowding. The pressure threshold decreases over time. Assume the effective contact area between pedestrians is 0.15m². 2 p max =4.13*10 4 N / m 2 In this invention, for the behavior of falling, at time [t] s ,t e At any given moment, the pedestrian pressure satisfies p. i <p i+1 <p i-1 This means that within a certain distance, the pressure value is lowest at the center of the disturbance, and the pressure behind it is higher than in front. Analyzing the pressure characteristics, such as... Figure 4 As shown, the scene is 4.5×4.5m. A pedestrian falls at (3.5, 3), denoted by FD (fall down). In the figure, v represents the overall flow speed and direction of movement of the crowd.

[0079] In crowded public places such as train stations, pedestrians tend to move in a relatively uniform direction at the ticket gates of the waiting hall, but queuing and pushing often occur, making it easy for pedestrians to fall. This embodiment assumes a 20×20m rectangular area for simulation. When the simulation step size is 30 (time t = 3.0s), a pedestrian falls, causing a sudden disturbance of abnormal crowd behavior. The disturbance location is (13, 10), and the direction of crowd movement is represented by the velocity v. The initial crowd density is set to ρ = 2p / m². 2 The initial disturbance ξ0 = 1.5, and the crowd pressure distribution diagram is as follows. Figure 5 As shown in the figure. The Z-axis represents crowd pressure, and FD (fall down) represents the pedestrian fall disturbance point. From... Figure 5 Analysis (5a) shows that the pressure at the disturbance point decreases sharply, while the pressure behind the disturbance point increases. From Figure 5 Analysis of (5b) shows that when time t = 3.0s, an abnormal fall occurs, and the crowd pressure at the disturbance point will increase again and spread outwards in a wave-like manner.

[0080] If the above methods are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0081] Example 2

[0082] This embodiment provides a pedestrian fall disturbance propagation simulation device, including a model building module, a simulation module, and a visualization module. The model building module, based on fluid dynamics theory, constructs a dynamic model of pedestrian fall disturbance propagation within a crowd, considering pedestrian fall disturbances. The simulation module, based on the dynamic model, sets pedestrian fall disturbance points and simulates pedestrian fall disturbance propagation in densely populated areas. The visualization module displays the simulation results. The dynamic model includes a crowd flow pressure term, which is constructed based on a pressure coefficient considering pedestrian fall behavior. When displaying the simulation results, the visualization module uses contour maps to describe pedestrian pressure at different locations. The rest is the same as in Embodiment 1.

[0083] Example 3

[0084] This embodiment provides an electronic device, including one or more processors, a memory, and one or more programs stored in the memory, the one or more programs including instructions for executing the pedestrian fall disturbance propagation simulation method as described in Embodiment 1.

[0085] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for simulating the propagation of pedestrian fall disturbances, characterized in that, Includes the following steps: Based on fluid dynamics theory, a dynamic model of the propagation of disturbances within a crowd that takes into account pedestrian fall disturbances is constructed. Based on the dynamic model of disturbance propagation within the crowd, a pedestrian fall disturbance point is set, and a simulation of pedestrian fall disturbance propagation in densely populated areas is conducted, with simulation results displayed. The crowd internal disturbance propagation dynamics model includes a crowd flow pressure term, which is constructed based on a pressure coefficient that takes into account pedestrian fall behavior. The stress coefficient that takes into account pedestrian fall behavior is expressed as follows: in, γ Indicates the pressure coefficient. p This indicates pedestrian stress when a pedestrian falls. F Indicates the pedestrian's center of mass; The pedestrian pressure at different locations within the crowd when pedestrians fall is described. p The calculation formulas are different, specifically: For pedestrians who fall i Its pedestrian pressure Represented as: For pedestrians behind i -1, its pedestrian pressure p i-1 Represented as: For the pedestrians ahead i +1, its pedestrian pressure p i+1 Represented as: Among them, subscript b Indicates pressure from behind, subscript f Indicates pressure ahead. p 0 represents pedestrians i Frontal or rearal pressure when no fall occurs. t s pedestrian i The moment the fall occurred, t e pedestrian i The moment of the fall ended, k This is the instantaneous attenuation coefficient.

2. The pedestrian fall disturbance propagation simulation method according to claim 1, characterized in that, The dynamics model of disturbance propagation within the crowd is constructed based on the AR traffic flow model.

3. The pedestrian fall disturbance propagation simulation method according to claim 1, characterized in that, The pressure coefficient ranges from 1 to 1.

7.

4. The pedestrian fall disturbance propagation simulation method according to claim 1, characterized in that, The crowd flow pressure term is expressed as: ,in, ρ Indicates population density. γ Indicates the pressure coefficient. ξ Indicates the intensity of the disturbance.

5. The pedestrian fall disturbance propagation simulation method according to claim 1, characterized in that, The simulation results shown are as follows: Contour maps are used to depict pedestrian pressure at different locations.

6. The pedestrian fall disturbance propagation simulation method according to claim 5, characterized in that, The contour maps include planar contour maps and three-dimensional contour maps.

7. A computer-readable storage medium, characterized in that, Includes one or more programs executable by one or more processors of an electronic device, the one or more programs including instructions for performing the pedestrian fall disturbance propagation simulation method as described in any one of claims 1-6.

8. An electronic device, characterized in that, It includes one or more processors, memory, and one or more programs stored in the memory, said one or more programs including instructions for performing the pedestrian fall disturbance propagation simulation method as described in any one of claims 1-6.

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