Optimization of Parameter Identification for Flutter and Flying Qualities

An important outcome of both flutter and flying qualities flight testing is the assurance of safe aircraft operation within its operational flight envelope. The objective of flutter testing is to demonstrate that the aircraft is aeroelastically stable within the envelope, while the objective of flying qualities testing is to demonstrate that the aircraft is controllable within the envelope. Although the frequency ranges of interest are quite different, both flutter and flying qualities testing traditionally require several minutes of data at a given flight condition using frequency sweep, chirp, or other long duration inputs from which critical parameters can then be estimated. To dramatically reduce this time to five seconds or less, Systems Technology, Inc. (STI) proposes to create a software solution based on the use of innovative parameter identification techniques that work with short duration, pulse-like inputs, which are easily generated by a pilot in a flight test environment. Wavelet-based techniques are used to identify frequency responses from which damping and frequency of critical flutter modes or flying qualities metrics can then be determined as part of on-line flight test activities.