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 ldquocrossoverrdquo 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 high-level control methods relating to active safety, as in automated collision avoidance systems.