Abstract:

Automated vehicles may encounter non-nominal situations called failure scenarios, due for instance to errors in perception or environment prediction. In some failure scenarios, a risk area must suddenly be avoided, possibly at the price of no longer satisfying all the constraints enforced in nominal driving conditions. We propose a design for a failure-safe controller that operates the vehicle according to the specifications in nominal conditions, while ensuring that, should a known failure occur, an evasive maneuver can be performed that avoids the risk area and satisfies a possibly relaxed set of driving constraints. We design evasive maneuver controllers parametrized in their reference, and we leverage set based methods to determine the region where such controllers satisfy the constraints and avoid the risk area. Membership in such a region during nominal operation is achieved by imposing additional constraints on the controller for nominal driving. We demonstrate the approach in simulations in a few different scenarios.