Description: Aurora Flight Sciences proposes to develop a system for robust engine control based on incremental sampling, specifically Rapidly-Expanding Random Tree (RRT) algorithms. In this concept, the task of accelerating or decelerating the engine is treated as a path planning exercise. The control system actively searches for actuator inputs that allow the engine to traverse power settings without entering undesired regions of operation. The search is based on the sequential construction of control actions that satisfy feasibility constraints given the system dynamics. These algorithms have been proven to converge to the optimal solution through repeated iteration. RRTs allow for an efficient search of the solution space, reducing the computational expense of determining the best sequence of inputs with which to control the engine. This allows an efficient, online method for an engine to adapt and recalibrate to unexpected operational conditions.

Benefits: The ability of systems to autonomously perform complicated planning processes is becoming increasingly important in modern aircraft. This is especially true with UAV's, which do not have the native ability of human operators to analyze and react to unexpected events. The proposed technology can be applied to increase the reliability of a variety of autonomous and remotely piloted vehicles as part of a global robust flight control for almost any UAV application. This can contribute to increased reliability and help reduce concerns about UAV operation over populated areas or in heavily trafficked airspace.

The proposed incremental sampling control technology could have a direct impact on the ability of an aircraft engine to autonomously adjust for unforeseen, adverse conditions. NASA has previously been involved in developing these sorts of technologies for aircraft systems in the Integrated Resilient Aircraft Control (IRAC) project. The proposed technology would allow for similar resilient characteristics on engine systems. This technology could be applied to a variety of NASA research areas requiring complex propulsion control, such as hypersonic flight.