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Meeting	ACGS Committee Meeting 100 - Cocoa Beach - October 2007
Agenda Location	4 GENERAL COMMITTEE TECHNICAL SESSION 4.1 Research Institutions, Industry, and University Reports 4.1.1 Research Institutes and Companies 4.1.1.9 Systems Technology Inc.
Title	Systems Technology Inc.
Presenter	David Klyde
Available Downloads*	presentation
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Abstract	For Meeting #100 of the Aerospace Guidance and Control Systems Committee, Systems Technology, Inc. (STI) is pleased to present short summaries of two ongoing Phase II Small Business Innovation Research programs that are both being conducted for the Air Force Flight Test Center. The first program is entitled “Optimization of Parameter Identification for Flutter and Flying Qualities” and this update focuses on the flying qualities aspects of the work. The second program is entitled “Aeroservoelastic Predictive Analysis Capability” and this update focuses on the Phase I open loop results. An important outcome of flying qualities flight testing is the assurance of safe aircraft operation within its operational flight envelope. Modern test techniques typically require several minutes of data at a given flight condition using frequency sweep, chirp, or other long duration inputs from which critical flying qualities parameters can then be estimated. To dramatically reduce this time to five seconds or less, STI is investigating the use of innovative parameter identification techniques that have been shown to work best with simple pulse-like inputs that are easily generated in a flight test environment. The techniques can be used to generate frequency responses from which flying qualities parameters can then be determined. In this paper the new Narrowband Signature frequency domain identification technique recently developed at STI is described. The technique is then applied to a limited set of flight test data generated with the Calspan Learjet 25 in-flight simulator. Results are compared with the known aircraft “truth model.” Modern flight control systems 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. Modeling and simulation tools such as AERO combine structural dynamics and aerodynamics with thousands or even millions of degrees of freedom. In this update, the feasibility of including a flight control system and actuator models as part of the high fidelity simulation is demonstrated. An F/A-18C fighter aircraft is used as an example problem. The combined modeling tool will more reliably predict adverse ASE interactions and thereby improve flight-testing near envelope boundaries. Furthermore, a CFD-based reduced-order model can be obtained for use in control system design and faster simulation. Technical issues addressed include developing movable CFD grids that conform to a moving control surface and a stable projection in place of a longitudinal control system.