Rapid generation of backup trajectories for run-time assurance of vehicles and other dynamical systems

The ability for agents to arbitrarily control a safety-critical vehicle system comes with the necessity for this system to feature a "flight envelope protection system," should the agent erroneously or deliberately drive the system into hazardous situations. This need is particularly true of systems evolving in environments containing obstacles, either physical or otherwise. The "flight envelope protection system" aims to take over the vehicle’s guidance before collision with the obstacle is unavoidable. Also named run-time assurance, the system generates "safe exit trajectories" in real time. This work provides a novel solution approach that follows a two-step process: First, reference backup trajectories are generated, together with trajectory regulation control laws, using a comprehensive but possibly time-consuming and unreliable trajectory optimization software. Second, we generate backup trajectories in real time by activating the regulation loop of a neighboring reference trajectory and computing the resulting trajectory. Numerical examples illustrate the approach. The work builds upon that previously reported in [1].