A Group Pedestrian Model Based On Velocity Obstacle Theory

Pedestrian safety and efficient operation are becoming more and more important in the design and plan of large-scale transportation hubs,shopping centers and roads.To help designers and engineers understand the behavior of pedestrian flow in pedestrian facilities,it is necessary to have a reasonable pedestrian movement model system and to build simulation software based on the system.Pedestrian groups are an important part of the crowds,but the study of the effect of group is very rare.It’s still unclear how group pedestrians avoid other people in microscopic level,and how the group effect influences the crowd in macroscopic level.It is for this reason that this paper intends to establish a new model of group pedestrian,which can show the social association between group pedestrian intuitively and effectively,and take reasonable avoidance strategy,provide some help and ideas for the establishment of large-scale pedestrian simulation model.The main contents of this paper are as follows:(1)Determination of basic theoretical framework.This paper analyze the advantages and disadvantages of the models commonly used in independent pedestrian modeling,and review the existing domestic and foreign research on group pedestrians.Due to the successful application of velocity obstacle theory in robot avoidance movement,this paper decides to use the velocity obstacle theory as the basic frame of the model,and construct a group pedestrian model in this framework.(2)Analysis of pedestrian walking characteristics.It is necessary to have a basic understanding of what the model will produce before micro-modeling.This requires enough basic data and a detailed understanding of the microscopic and macroscopic behavior of pedestrian movement.Therefore this paper describes the latest research from the aspects of pedestrian speed,space demand,pedestrian interaction,pedestrian traffic flow,self-organization of pedestrian flow,and pedestrian space structure.And put forward some factors need to be considered in modeling.(3)Model establishment.As the theory of velocity obstacle can ensure that no collision occurs,this paper builds a group model on this basis,and proposes to link the scattered pedestrians with the concept of distance constrained line.First,the intra-constrained line is used to construct the two-pedestrian group and the three-pedestrian group.Then the individual,two-pedestrian group and three-pedestrian group are connected with the inter-constrained line to form a large group of pedestrians.Subsequently,this paper proposes an algorithm that transforms the distance constraint into the velocity constraint and ensures that the model always has a solution.(4)Model calibration,simulation and verification.Firstly,the coefficients in the model are calibrated by using the video data.Secondly,the two-pedestrian group and the three-pedestrian group opposite experiments are designed,and the avoidance characteristics of the two groups are verified respectively.After ensuring a low-density collision-free motion,a circular high-density interaction experiment is designed,although the overlap in the central region is difficult to avoid,the avoidance characteristic at high density is still valid.Finally,in the macroscopic experiment,the model generates the lane formation phenomenon,and a reasonable fundament diagram.Therefore,it is considered that the multi-pedestrian avoidance model established in this paper is effective.