Set-based multi-objective control of metered ramps at ring road junctions

Journal article, 2020

A set-theoretical approach is presented for a multi-objective control design of the local ramp metering problem. Two control objectives are specified: first, the optimization of traffic performance, by the minimization of total time spent. Second, the emission factor of CO2 needs to be minimized. The optimal state for traffic emission however lies in the unstable domain of the dynamic system. To dissolve this inconsistency, the control problem is formalized for the multi-objective optimization problem by using set-theoretical methods. For this purpose, the non-linear model METANET is rewritten in a shifted coordinate frame with a parameter-varying, polytopic representation. Bounds on state-, input- and disturbance variables are expressed by convex polytopes. These sets are then used for the design of an interpolated Hinf controller that is capable of improving traffic conditions according to the prescribed multi-objective criteria