Description: Adaptive control offers an opportunity to fulfill aircraft safety objectives though automated vehicle recovery while maintaining performance and stability requirements in the presence of unknown or varying operating environment. Future aircraft are a natural application of adaptive control. These aircraft will be more fuel efficient, have longer operating ranges though more flexible aircraft structures. This increased flexibility will tightly couple structural and rigid body modes. The traditional control approaches to address the aeroservoelastic (ASE) will not work due to this coupling. Furthermore, the application of adaptive control to these flexible aircraft may result in undesired ASE excitation leading to structural damage or failure. Hence an integrated flight control system is needed for gust load alleviation, flutter suppression and rigid body control of the aircraft which works in concert with the adaptive control system for improved resilience and safety. MUSYN proposes an integrated approach based on linear, parameter-varying (LPV) control to the design of integrated flight control algorithms. Phase II research is focused on developing a fully functional prototype tool suite to model, identify, analyze, design, simulate and implement in real-time, linear, parameter-varying (LPV) ASE controllers. The objective is to combine the integrated LPV flight control system with adaptive control to preserve rigid body performance during upsets while mitigating ASE effects. The prototype LPV tools will be used to analyze and design an inner-loop LPV ASE and adaptive outer-loop controller for the MAD-MUTT test vehicle. The LPV designs will be validated in software-in-the-loop and hardware-in-the-loop testing prior to their implementation and flight test on the MAD-MUTT vehicle. The objective is to demonstrate the viability of the LPV tools suite to analyze and synthesize integrated controllers for highly flexible aircraft.

Benefits: The immediate NASA application will be the Multi-Utility Aeroelastic Demonstrator (MAD), Multi Utility Technology Test-bed (MUTT)vehicle being transferred to NASA Dryden in Summer 2012. This aircraft will provide an experimental flight test capability for aeroservoeleastic control research. Lockheed Marting and the USAF developed this test bed to investigate the use of active control strategies for highly flexible aicraft. The MAD-MUTT vehicle is an ideal facility to use the LPV framework for modeling, identification, analysis, control, simulation and real-time implementation of LPV controllers. The proposed research will develop an integrated LPV flight control for the MAD-MUTT test vehicle. The performance and robustness of the LPV design will be accessed and compared with a baseline aeroservoelastic system.

Non-NASA commercial applications fall under two categories: (1) Uninhabited aerial systems (UASs) like SensorCraft, for intelligence, surveillance and reconnaissance (ISR) and (2) Space, automotive and ship transportation systems. MUSYN or the companies it has worked with have already demonstrated the application of LPV control techniques to aircraft, launch vehicles, automotive suspensions, trucks, missiles and underwater vehicles. All these systems are seeing increased aeroservoelastic coupling due to the push for more efficient, lightweight structures. The software tool develop in the SBIR addresses a unique need that is currently only being addressed by European aerospace companies using proprietary software tools. A Matlab based LPV Control Toolbox would address a need in the US aerospace and transportation communities and complement the robust control tools already developed MUSYN.