Two-level hierarchical optimal control for urban traffic networks

A two-level hierarchical optimal control method is proposed in this paper. At the upper level, the reference signals (set-point) are optimized with a data-driven model-free adaptive control (MFAC) method. Traffic signals are regulated with the model predictive control (MPC) with the desired reference signals specified by the upper level. The main contribution is that the set-point optimization is addressed by using the MFAC method which does not need modeling of the traffic system dynamics. Moreover, through this scheme, the planning of vehicle distribution in a road network and the operation of traffic signal control can be executed simultaneously. The effectiveness of the proposed method is testified by an urban traffic network based on MATLAB and VISSIM 9.0 and is also demonstrated by the comparison results with the back-pressure traffic signal control and traditional MPC.