Asymptotic Tracking Control of Freeway Traffic Density via Ramp Metering

The method of the robust integral of the sign of the error was used to design the ramp signal for traffic flow system of freeway with uncertaines . Uncertain terms are allowed to be modelled or unmodelled.The unmodelled terms in the model were estimated by there bounded differential . Compared with other ramp metering method, this controller is designed without approximately linearizing the complicated nonlinear model and requiring the upper bound of unmodelled terms known .The control gain is reduced .The method is verified to be robust subject to both external disturbances and unmodelled dynamics ,and to be adaptive to unknown parameters . The numerical example shows good tracking performance .