Hierarchical freeway control based on the composition of PID controller and CMAC

The hierarchical structure and CMAC (cerebellar model articulation controller) are used for freeway ramp metering. The macroscopic model to describe the evolution of freeway traffic flow is first established. The algorithm of the composition controller of PID and CMAC is then studied. There are two control layers in this control architecture: the coordinated control layer is responsible for computing the desired state of each segment, and the direct control layer is in charge of the ramp metering rate via the composition controller of PID and CMAC. Finally, the control system is simulated in MATLAB software and fuzzy logic control is also chosen in contrast to the composition control. The result shows that the composition controller improves evidently on the aspects of response speed and dynamic performance. This method can effectively eliminate traffic jams, and can make vehicles travel more efficiently and safely.