Nonlinear crossover model of vehicle directional control

This paper develops a simple nonlinear control model to represent the dynamics of a coupled vehicle-driver system. It is applied to an analysis of delay and preview time in closed-loop control. The model is a reduced-order non-linear model based on a separation between kinetic and kinematic driver control components. In kinetic control, vehicle dynamics and compensatory actions are represented in a fashion similar to the well-known linear crossover model; kinematic control takes the form of a reference velocity derived from the local roadway. Analytic stability results are developed, providing specific relationships between minimum preview, speed, time-delay and disturbance amplitude. The analysis is developed quite generally, but is applied in detail to straight-line path following on a flat horizontal road. Predictions are validated using results from one specific experimental study. The model is suitable for developing highlevel control methods relating to active safety, as in automated collision avoidance systems. © 2009 AACC.