Freeway on-ramp control based on the composition of PID controller and CMAC

The composition control method based on cerebellar model articulation controller (CMAC) and PID controller is proposed to regulate the number of vehicles entering a freeway entrance point. First, the freeway traffic flow dynamic model is built. Then the algorithmof the composition controller of CMAC and PID is formulated. In conjunction with nonlinear feedback theory, the on-ramp metering rate of a freeway is determined by using the composition controller. Finally, the control system is simulated in MATLAB software and fuzzy logic controller is also chosen in contrast to the composition controller. The result shows that the composition controller improves evidently on the aspects of response speed and dynamic performance. It can achieve a desired traffic density along the mainline of a freeway, and can make vehicles travel more efficiently and safely. This method provides a novel and practical way to realize freeway on-ramp metering.