Freeway ramp metering based on particle swarm optimization

摘要

A proportional Plus Integral (PI) control method and a particle swarm optimization algorithm are presented for freeway on-ramp metering in this paper. First, a Cell Transmission Model (CTM) for describing the evolution process of traffic flow is set up. Then, the optimization procedures of a particle swarm algorithm for optimizing PI parameters are given in detail. In conjunction with nonlinear feedback control method and CTM, particle swarm optimization based PI controllers for freeway ramp metering are designed. Finally, the feedback controllers are simulated in MATLAB software. The results show that this method has such advantages as fast response, excellent dynamic and steady-state performance. This approach can eliminate traffic congestion and maintain the stability of freeway traffic flow.