H∞ Control Approach to Freeway Ramp Metering

This paper proposes a robust control approach for designing local traffic-responsive ramp metering as the directed control level in the hierarchical system. The control dynamic model is built concerning the freeway and its on-ramp, and the H∞control algorithm is formulated. Traffic simulation results demonstrate that the H∞control compares favorably against the well-known linear quadratic optimal control strategy, particularly at situation where the disturbance inputs (the traffic demand and the volume divert) vary greatly or traffic conditions changed.