Passenger Evacuation Of Subway Train Based On Virtual Reality Technology

The urban rail transit system is characterized with crowd passengers and closed space.There are risks of large passenger flow,congestion and emergency evacuation.Especially in the case of fire,passenger safety is great threated.Existing studies have not paid enough attention to passengers’ movement around the train carriage.In evacuation studies,passengers’ evacuation time in the carriage is usually neglected,and the regulations of passenger evacuation in tunnels are not clear.At the same time,due to the limitation of experimental conditions and personnel safety,the understanding of the characteristics of complex evacuation behavior of passengers under fire conditions is insufficient.The lack of relevant data has become a bottleneck of the study on evacuation safety in urban rail transit.Therefore,this paper focuses on passenger movement and emergency evacuation in train carriage of urban rail transit.This paper analyzed the characteristics of passenger movement inside and outside the train,constructed an interactive experimental platform for subway evacuation based on virtual reality technology to study passenger evacuation under subway fire by immersion experiments and multiple data acquisition methods.The evacuation characteristics and safety of passengers in different conditions are also analyzed by computer simulation.According to the results of investigation,experiment and simulation,reasonable emergency evacuation suggestions are put forward.This provides strong theoretical basis and data support for operation safety,emergency management and intelligent decision-making of urban rail transit.Firstly,considering the characteristics of building,facilities and environment in urban rail transit system,a multi-agent passenger movement simulation system suitable for urban rail transit is constructed.And this lays the foundation for the motion modeling of virtual passengers in VR experimental platform.At the operational level,based on multi-agent theory,combined with molecular dynamics and social force model,the passenger’s movement and force characteristics in the carriage and in the process of alighting and boarding are analyzed,and the simulation model of passenger in metro train is established.On this basis,the factors influencing passenger movement and evacuation efficiency are analyzed.At the strategic and tactical level,based on the analysis of the characteristics of passenger path planning in urban rail transit,considering the motivation,preference and various uncertainties of passenger selection,a two-level dynamic path planning algorithm based on predicted time is proposed.It enable pedestrians the ability of intelligent and autonomous route plan.Based on the analysis of the evacuation process and the questionnaire survey of passengers’ evacuation psychology and behavior under subway fire,the virtual reality technology is introduced,and the virtual reality interactive simulation experimental platform for emergency evacuation of subway is designed and constructed by Unity3 D and 3D Max.It provides a new method of passenger evacuation study under fire conditions.The experimental platform consists of four main parts: device,scene,data interaction and evacuation resource.Different experimental scenes and parameters can be set up by Server.Through virtual passenger and multi-user connection,the investigation of social behavior in evacuation is realized.The control of virtual passenger is realized by loading the multi-agent simulation system.In order to build a vivid fire scene,considering the combustion characteristics and location of materials in vehicle,the development of train fire is simulated by CFD with non-uniformity grids.The characteristics of subway train fire are analyzed,and the simulation results are loaded into the experimental platform.It is used to realize the dynamic visualization display of fire scene and to dynamically evaluate the survival status of evacuees in fire environment.With the VR interactive experimental platform and human experiment,combined with multiple data acquisition methods such as video recording,dynamic coordinate capture and heart rate tracking,the first-hand data of passengers in the whole evacuation process of trains,platforms and tunnels in fire environment is obtained by the means of realistic immersion evacuation environment,real passenger movement and emergency response.Based on the obtained multi-source data,questionnaire and interview,the behavior,movement and psychological characteristics of passengers in evacuation were analyzed.The time spent in each stage,speed,various non-evacuation behaviors and the influencing factors during evacuation were obtained.Through video analysis,subjective evaluation and analysis of heart rate variability data,the method of quantitatively describing the degree of passenger panic was supposed.The effect of panic on passenger behavior and movement are studied.Based on the passenger characteristics of evacuation obtained from investigations and experiments,the passenger safety of fire evacuation in subway train is studied by simulation.Passengers’ individual attributes,motion parameters(motor ability,reaction time,expected speed,etc.)and behavior mechanism are set according to the results of experiments and questionnaires.Based on the established model,the necessary safe evacuation time of all existing train types in Beijing Metro under different passenger loads under cases of platform evacuation,platform evacuation and rail evacuation are analyzed.In view of the disadvantage of evacuation in tunnel,passenger evacuation and fire evolution are combined to conduct comprehensive simulation of emergency evacuation with different composition of passenger loads,fire location,environmental control and evacuation organization.In the aspect of fire evolution,based on computational fluid dynamics(CFD),the numerical evolution of full-scale train fire in tunnel under different working conditions is simulated.The material and boundary conditions inside vehicle are set up according to the actual situation.The influences of environmental control and evacuation organization on fire development are studied from the aspects of thermal radiation,temperature,oxygen content and smoke concentration.The dynamic expansion of fire in evacuation environment is realized by the divided small space.The effects of fire on evacuees are quantified by FED.Finally,the rate of successful escape,the location and the time of casualty,the available safe evacuation time and success rate of each carriage under different conditions are obtained.Suggestions of emergency response and evacuation rescue under different fire conditions are put forward.