Four wheel steering control system design using fuzzy models

A fuzzy logic four wheel steering control system design method using a vehicle fuzzy model is described in this paper. The controller design consists of two stages: 1) an optimal steering controller is constructed for each local model that is a part of the fuzzy model; and 2) local controllers are combined using fuzzy rules to form a fuzzy logic controller. The performance of the fuzzy controller is tested on the vehicle fuzzy model and on the nonlinear detailed vehicle model. Simulations indicate that the dynamic properties of the detailed nonlinear vehicle model are captured with the simple fuzzy model. The fuzzy model's dynamic responses are much closer to the responses of the nonlinear model as compared with those of the linearized model.