Research Of Crowd Evacuation Simulation Based On Potential Field Model

During the holidays, a huge number of crowds gather in public places. Forexample, many passengers gather in the station during the Chinese Spring Festival.There is a strong need for crow evacuation simulation to plan various public facilitiesand to work out a rational evacuation plan in crisis situation.This paper summaries and analyzes various methods at home and abroad in thepast three decades about the crowd simulation. Then we select the potential fieldmethod to study, and the main work is as follows:Firstly, the traditional potential field method is easy to generate a local optimumvalue problem. We introduce the Neumann boundary condition. Setting the normalderivative as zero, the repulsive force of the obstacle on the virtual pedestrian isweakened and the generation of the local optimum value is eliminated. On this basis,aimed at the vaulted phenomenon of evacuation, the traditional potential fieldmethods and the Neumann boundary conditions potential field methods are compared,showing that the latter has better simulation results. In addition, by the weightedsuperposition of the traditional potential field method and Neumann boundaryconditions potential field method, it is flexible to control the repulsive force of theobstacle on the virtual pedestrian, in order to get better result in different scenarios.Secondly, for solving the linear equation of the potential field method, this paperintroduces three commonly used iterative methods. We analyzed these iterativemethods in Dirichlet boundary condition problem and Neumann boundary conditionproblem and points out the best linear equations solution of the potential field methodin scenarios with different sizes and different conditions. In addition, on this basis,this paper proposes a new path planning method which using the error term of thesolution of Neumann boundary condition problem. This method is well adaptive thatit does not need to pre-set the boundary condition for each scene.Then, as a macro model the potential filed method is not good at simulating themicro characteristics of the virtual pedestrian. This paper proposes three micro optimization strategies: local potential field, update strategy and speed control. By thelocal potential filed, it is effective to control the distance between the virtualpedestrians. By comparing the randomized update strategy and the non-randomizedupdate strategy, it is able to simulate the pedestrians in queue or not queue. By thespeed control strategy, it is possible to simulate the impact of congestion on the virtualpedestrians’ speed.Finally, this paper builds up a three dimensional evacuation simulation prototypesystem in the DXUT framework, using the DirectX graphics interface. Synthesizingall the factors this paper mentioned about the crowd evacuation simulation, wesimulate the real scenarios: subway station, intersection, office and large square toshow our work has certain value in engineering applications.