Rule-Based Behavior Planning to Resolve Separation Loss in UAM Off-Nominal Situations

This paper develops an on-the-fly decision-making framework to address the separation losses caused by off-nominal conditions, such as Loss of Control In-flight (LOC-I) of aircraft in congested Urban Air Mobility (UAM) airspace. Often, separation loss caused by LOC-I results in subsequent separation losses, triggering domino effects as one aircraft maneuvers to avoid another aircraft experiencing LOC-I in congested airspace. A behavior tree-based decentralized decision-making is developed to execute a separation assurance task assigned by the Provider of Service (PSU) to UAM aircraft, coordinating and selecting the necessary maneuvers following Federal Aviation Administration (FAA) right-of-way rules to resolve the encountered separation losses. The significance of the proposed decision-making framework is demonstrated through simulations that consider separation loss scenarios arising from LOC-I by implementing on-the-fly conflict detection, tasking, and maneuver planning algorithms for aircraft involved in the conflict.