Design and Simulation of Speed Limit Controller Based on Fuzzy Logic Inference

Speed limit control is of great importance in freeway traffic control. This study aims to determine the reasonable speed limit through the application of a fuzzy inference method. Firstly, the components of a fuzzy logic controller are formulated. Then the influential factors of speed limit control are analyzed and the speed limit controller based on fuzzy logic is designed according to such information as the number of vehicles on the freeway, the road grade, and the weather conditions. Gauss, g-bell and triangle curves are used for the membership functions of the fuzzy variables. The rule base including 45 fuzzy rules is also established. Finally, the speed limit controller is simulated. Simulation results show that the speed limit values are reasonable. Fuzzy inference method provides a novel and practical way to realize speed limit control.