  This paper proposes a Robust Safe Control Architecture (RSCA) for
safe-decision making. The system to be controlled is a vehicle in the presence
of bounded disturbances. The RSCA consists of two parts: a Supervisor MPC and a
Controller MPC. Both the Supervisor and the Controller are tube MPCs (TMPCs).
The Supervisor MPC provides a safety certificate for an operating controller
and a backup control input in every step. After an unsafe action by the
operating controller is predicted, the Controller MPC takes over the system. In
this paper, a method for the computation of a terminal set is proposed, which
is robust against changes in road curvature and forces the vehicle to reach a
safe reference. Moreover, two important proofs are provided in this paper.
First, it is shown that the backup control input is safe to be applied to the
system to lead the vehicle to a safe state. Next, the recursive feasibility of
the RSCA is proven. By simulating some obstacle avoidance scenarios, the
effectiveness of the proposed RSCA is confirmed.
