Variable Structure Model Reference Adaptive Control, for Vehicle Automatic Steering System

A variable structure model reference adaptive control (VS-MRAC) strategy for automatic active steering of a two wheel steering car is proposed. An ideal steering system with fixed properties and moving on an ideal road is used as the reference model, and the automatic active steering system is forced to attain the same behavior as the reference model. The proposed system can treat the nonlinear relationships between the side slip angles and lateral forces on tire, and the uncertainties on friction of the road surface, whose compensation are very important under critical situations. Simulation results show improvements on side slip, yaw rate and Dy angle.