System Dynamics and Feedback Control Design Problem formulations for Real Time Ramp Metering

This paper formulates the ramp metering control problem as a real-time feedback control problem. The development is shown by modeling freeway sections, and hence the results are immediately applicable to isolated ramp metering problems. The ideas presented in this paper can be utilized to develop coordinated ramp metering feedback control techniques. Three different forms of the formulation for are presented: (1) distributed parameter system form derived from the conservation law; (2) space discretized continuous lumped parameter form; (3) space and time discretized lumped parameter form. These formulations can be considered as the starting points for development of feedback control laws for the different control problems stated in this paper. This paper presents the feedback control problems and a new nonlinear control design for an isolated ramp metering problem. Simulations are performed for the isolated case using the new nonlinear feedback control law which show very encouraging results.