Active Adaptive Flexible Motion Controls with Aeroservoelastic System Uncertainties

Active/Adaptive Flexible Motion Controls with Aeroservoelastic System Uncertainties

Most aeroservoelastic analyses of modern aircraft have uncertainties associated with model validity. Test-validated aeroservoelastic models can provide more reliable flutter speed. Tuning the aeroservoelastic model using measured data to minimize the modeling uncertainties

is an essential procedure for flight safety. However, uncertainties still exist in aeroservoelastic analysis even with the test-validated model due to time-varying uncertain flight conditions, transient and nonlinear unsteady aerodynamics, and aeroelastic dynamic environments. For flexible motion control problems, a control law that adapts itself to such changing conditions is needed. Active and adaptive control of these coupled mechanisms is mandatory for stabilization and optimal performance in such time-varying uncertain flight conditions.

The primary objective of this research is to study the application of a digital adaptive controller to the flexible motion control problems. This can be achieved by introducing online parameter estimation together with online health monitoring. Structural response information at

the selected sensor locations will be used for the online parameter estimation. The second objective of this research is to develop a simple methodology for minimizing uncertainties in an aeroservoelastic model.

Work to date: The team has modeled known uncertainties.

Looking ahead: Future activities involve further refinement of the models, which will involve flight tests currently planned for 2015.

Partners: Lockheed Martin Advanced Development Program has provided the X-56A FEM and test data. The Air Force Research Laboratory will provide X-56A vehicles and ground control systems. Other NASA Centers have contributed to this effort as has the University of Texas at Austin.

Benefits

 Economical: Enables high-precision simulation prior to expensive flight tests

 Smoother ride: Permits superior ride-quality control

Applications

 Resulting models apply across a wide range of aircraft

Hyperelastic Research/Lightweight Flexible Aircraft

Armstrong engineers are pioneering new research in aircraft design and modeling. Researchers are experimenting with revolutionary hyperelastic wing control technologies that can reduce weight, improve aircraft aerodynamic efficiency, and suppress flutter. Other cutting-edge research involves techniques, models, and analysis tools for flutter suppression and gust-load allevia-tion.Flight projects at Armstrong rely on high-performance aircraft that can support research on lightweight structures and advance control technologies for future efficient, environmentally friendly transport aircraft. This work has applicability beyond flight safety and design optimization.Armstrong's R&D capabilities in this area also can be applied to other vehicles, such as supersonic transports, large space structures, and hypersonic vehicles.