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This study examines the stability of pedestrian flow in a 2D OV model with asymmetric interaction through linear stability analysis. The analysis includes the 1D OV model, 2D OV model, asymmetric interaction, and conclusions drawn from the findings.
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Stability Analysis of Pedestrian Flow in 2D OV Model with Asymmetric Interaction Tian Huan-huan Xue Yu August 13, 2013
Outline • Review the 1D OV Model • Review the 2D OV Model • The 2D OV Model with the asymmetric interaction • Linear stability analysis • Conclusions
1. The 1D OV Model • ------the coordinate of the nth vehicle • -----the acceleration • -----------the driver’s sensitivity • -----the optimal velocity (OV) function [1] BANDO M, HASEBE K, NAKAYAMA A, et al. Phys. Rev. E, 1995, 51:1035–1042.
2. The 2D OV Model (TOVM) • -----the position of jth pedestrian • -----the desired velocity • -----the interaction between pedestrians [2] SUGIYAMA Y, NAKAYAMA A, HASEBE K. PED’01, 155-160 [3] NAKAYAMA A, HASEBE K, SUGIYAMA Y. Physical Review E, 2005, 71:036121.
The strength of the interaction is determined by the distance (between jth and kth pedestrians) and the angle (between and ); • indicated that the pedestrian is more sensitive to pedestrians in front than those behind.
The interaction is • The first derivative of the function is centered on the inflectant point; That’s to say, the process of the acceleration and deceleration is symmetrical in the pedestrian flow, so the interaction between pedestrians is symmetrical. • In reality, the response to the acceleration and deceleration is different. Especially in a high-density situation, in order to avoid collision and pushing, pedestrians are willing to slow down, which is similar with drivers’ behavior.
The homogeneous solution of equation (1) is is a constant vector ; is a constant velocity . Consider a small perturbation as follows:
(2) The linearized equations of equation(1) are (3) where
Suppose that the small wave propagates at the angle with the x axis.
The 2D wave is classified into two types of modes: longitudinal mode and transverse mode. • The longitudinal mode The linearized equations (2) and (3) are
The transverse mode The linearized equations (2) and (3) are
4. Conclusions • The asymmetrical interaction between pedestrians is considered in the 2D OV model. • The stability of homogenous flow is investigated with linear stability analysis. • The phase diagram is obtained. • The critical curve of longitudinal mode move leftward along r-axis and the regions below the curves of longitudinal mode becomes smaller. The critical curve of transverse mode move rightward along r-axis.
The phase diagram is obtained. There are six regions above the critical curves in the new model. The region A in the original model is divided into two regions (A and E) in new model, the region C in the original model is divided into two regions (C and F) in new model.