Freeway On/off-Ramp Control Algorithm Based on ANN-PID

The mathematical model of the ramp control is formulated. The control objective is to maintain the freeway operated at a desired traffic density and to diminish the queue length on/off the ramp as short as possible. Integrated with artificial neural network, PID control was applied to a section from Lenovo Bridge to Ji-Men Bridge at the 3th ring-freeway of Beijing by simulating. Simulation results have been compared with the classic feedback algorithm ALINEA method. The results show that this algorithm is effective and can maintain the mainstream traffic flow density in a desired value.