A new PI controller for freeway ramp metering based on fuzzy logic

On-ramp metering is an effective tool for traffic management on freeway networks. In this paper, based on the ordinary differential equation (ODE) model of the ramp system, a new PI controller is designed by utilizing more priori traffic flow information of up-stream and down-stream. Meanwhile, the fuzzy control logic is developed to tune the PI parameters in real time according to the density tracking error and error variation. The simulation study shows that a better control performance is achieved for the proposed approach compared with the traditional PI controller.