Aeroservoelastic Predictive Analysis Capability

Modern flight control systems (FCSs) augment aircraft dynamics so the pilot can more effectively accomplish complex missions. These handling and performance benefits typically use high gain control systems that can result in adverse aeroservoelastic (ASE) interactions. Improvements in ASE modeling will improve flight envelope predictions, during both the design and flight test phases of a program. Modeling and simulation tools are available that combine aero and structural dynamics, but none include the FCS. A modification to an existing aero/structural software package is proposed that will do this, both for simulation and for estimation of reduced order models. This combined tool will more reliably predict adverse ASE interactions and can be used by the Air Force to improve flight-testing near envelope boundaries. The feasibility of this combined approach will be demonstrated in Phase I. High order actuator models are needed and will be included to correctly interface the FCS with the aerodynamic and structural parts. A fighter aircraft and its FCS will be added to the existing software, with sufficient fidelity to command aggressive maneuvers, at a flight condition known to have limit cycle oscillations. The Phase II effort will convert this general capability into a commercially viable tool.