Beyond Fault Diagnosis and Failure Prognosis Fault Tolerant Control of Aerospace Systems

ABSTRACT: Global Technology Connection, Inc., in collaboration with its academic and industrial partners proposes to develop a hierarchical 3-tier fault tolerant architecture to improve aircraft reliability, safety, and availability. The hierarchical system will support autonomous decisions for aircraft mission modification, trajectory planning, and low-level controller reconfiguration. At the low-level of the architecture, a Fault-Adaptive Control Technology (FACT) is used that continuously monitor for faults/failures and reconfigures low-level controllers using an active model approach in order to maintain stable control over the aircraft. The diagnostic and prognostic methodology will fuse health information at the aircraft component, subsystem, and system levels in order to improve the accuracy and reliability of the health assessment. Fault and failure information is sent to the top-level and mid-levels of the architecture to support mission and trajectory planning, respectively. Based on the current aircraft health state, a mission modification module determines the appropriate high-level control actions such as modifying the sequence of mission tasks and switching between different objectives (extend life / maintain control). A case-based reasoning module is used to draw upon past mission modification successful and failed experiences. At the mid-level, a path planner is then used to generate appropriate aircraft trajectories based on selected mission, environmental conditions, and current and predicted health states. Phase I shall concentrate on the fault tolerant architecture development and feasibility demonstration. In Phase II, a working prototype of the framework will be implemented and verified/validated on a relevant aircraft system. The technology will be transitioned to commercial applications in Phase III to both military and civilian aircraft applications as a framework package along with design and test tools. BENEFIT: The fault tolerant system, Fault Evaluation, Adaptation, and Tolerant System (FEATS), will provide improved reliability, safety, and available for manned and unmanned aircraft systems. The system can handle not only a single fault/failure, but multiple aircraft faults/failures from various aircraft subsystems and components. FEATS will provide reliable autonomous decision making in the presence of aircraft fault/failures to increase the chances of mission success and prevention of vehicle loss. There is huge commercial potential for this type of system in aircraft, ship and ground autonomous systems to detect and predict failures and provide on-line compensation for failed systems. NASA"s unmanned landing systems, commercial aircraft, automobiles, automated manufacturing, etc. could also benefit from this technology.