UC Berkeley

This thesis presents the design of a novel active

safety system preventing unintended roadway departures. The

proposed framework unifies threat assessment, stability, and

control of passenger vehicles into a single combined optimization

problem. A nonlinear Model Predictive Control (NMPC) problem

is formulated where the nonlinear vehicle dynamics, in closed-

loop with a driver model, is used to optimize the steering and

braking actions needed to keep the driver safe. A model of the

driver's nominal behavior is estimated based on his observed

behavior. The driver commands the vehicle while the safety

system corrects the driver's steering and braking action in case

there's a risk that the vehicle will unintentionally depart the

road. The resulting predictive controller is always active and

mode switching is not necessary. We show simulation results

detailing the behavior of the proposed controller as well as

experimental results obtained by implementing the proposed

framework on embedded hardware in a passenger vehicle. The

results demonstrate the capability of the proposed controller to

detect and avoid roadway departures while avoiding unnecessary

interventions.