Autonomous Wary Collision Avoidance

Handling of critical situations is an important part in the architecture of an autonomous vehicle. A controller for autonomous collision avoidance is developed based on a wary strategy that assumes the least tire-road friction for which the maneuver is still feasible. Should the friction be greater, the controller makes use of this, and performs better. The controller uses an acceleration-vector reference obtained from optimal control of a friction-limited particle, whose applicability is verified by using numerical optimization on a full vehicle model. By employing an analytical tire model of the tire-road friction limit, to determine slip references for steering, and body-slip control, the result is a controller where the computation of its output is explicit, and independent of the actual tire-road friction. When evaluated in real-time on a high-fidelity simulation model, the developed controller performs close to that achieved by offline numerical optimization.