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In this paper, we present a new single fixed controller approach based on the multivariable H2 control/regulator theory with internal model principle to solve a challenging control problem...

This paper presents a flight envelope protection system for NASA’s Transport Class Model. The developed protection scheme is based on a command-limiting architecture that accounts for aircraft adverse aerodynamics, unusual attitude, and structural integrity and is designed to augment a standard gain-scheduled flight control law. The scheme also includes an energy protection system, which relies on an automatic throttle control loop that implements a total energy control law. In the setup adopted, the limits of the protected envelopes are actively adjusted to ensure, on the one hand, that the aircraft always stays in a safe flight condition and, on the other hand, that the pilot has enough control authority to perform aggressive maneuvers, if needed. Batch simulations demonstrate the efficacy of the protection system in maintaining the aircraft within desired safe conditions.

Urban Air Mobility (UAM) - defined as safe and efficient air traffic operations in a metropolitan area for manned aircraft and unmanned aircraft systems - is being researched and developed by industry, academia, and government. Significant resources have been invested toward cultivating an ecosystem for Urban Air Mobility that includes manufacturers of electric vertical takeoff and landing aircraft, builders of takeoff and landing areas, and researchers of the airspace integration concepts, technologies, and procedures needed to conduct Urban Air Mobility operations safely and efficiently alongside other airspace users. This paper provides high-level descriptions of both emergent and early expanded operational concepts for Urban Air Mobility that NASA is developing. The scope of this work is defined in terms of missions, aircraft, airspace, and hazards. Past and current Urban Air Mobility operations are also reviewed, and the considerations for the data exchange architecture and communication, navigation, and surveillance requirements are also discussed. This paper will serve as a starting point to develop a framework for NASA's Urban Air Mobility airspace integration research and development efforts with partners and stakeholders that could include fast-time simulations, human-in-the-loop (HITL) simulations, and flight demonstrations.

Aircraft loss of control (LOC) is a leading cause of fatal accidents across all transport airplane and operational classes. LOC can result from a wide spectrum of precursors (or hazards), often occurring in combination. Technologies developed for LOC prevention and recovery must therefore be effective under a wide variety of conditions and uncertainties, including multiple hazards, and the validation process must provide a means of assessing system effectiveness and coverage of these hazards. This paper provides a detailed description of a methodology for analyzing LOC as a dynamics and control problem for the purpose of developing effective technology solutions. The paper includes a definition of LOC based on several recent publications, a detailed description of a refined LOC accident analysis process that is illustrated via selected example cases, and a description of planned follow-on activities for identifying future potential LOC risks and the development of LOC test scenarios. Some preliminary considerations for LOC of Unmanned Aircraft Systems (UAS) and for their safe integration into the National Airspace System (NAS) are also discussed.