Integrated threat assessment and control design for roadway departure avoidance

This paper presents the design of an active safety system for prevention of unintended roadway departures. In normal driving conditions, the driver fully commands the vehicle while the safety system corrects the driver´s steering and braking action in case there´s a risk that the vehicle unintentionally departs the road. A model of the driver´s nominal behavior is first estimated based on his or her observed behavior. A nonlinear model of the vehicle in closed loop with the driver is then used to reformulate the threat assessment and control problems as a combined optimization problem. The resulting predictive controller is always active and mode switching is not necessary. Experimental data collected using human drivers in a driver simulator demonstrate the capability of the suggested controller to detect and avoid roadway departures while avoiding unnecessary interventions.