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Fundamental Concepts and Methods

Point of Contact: Suresh Joshi

Fundamental Concepts and Methods

Multidisciplinary Modeling

Trends in advanced high-speed aircraft configuration design are toward statically unstable, flexible structures for achieving improved performance benefits. Whereas aerodynamics, structures, and propulsion systems models for rigid-body aircraft can be determined independently, flexible, unstable aircraft require an integrated approach. For example, airframe/engine interactions and structural airframe interactions may require an integrated aero/structural/propulsion models capability to determine critical interaction levels. Thus, a key objective is to develop methods for high fidelity modeling of aircraft. This requires (as a short list) significant advances in developing and understanding unsteady aerodynamics, structural dynamics, thrust vectoring effects, system identification theory, and uncertainty characterization.

ControlTheory

Control theory for advanced aircraft addresses three issues. Stability robustness, performance robustness, and controller implementation. Designing controllers for flexible, unstable aircraft which guarantee stability and performance robustness in the presence of uncertainties and disturbances is a considerable challenge for controls designers. Being able to implement a controller once found is even more of a challenge. The objective under control theory, therefore, is to develop multivariable control and order reduction methodologies for both plants and controllers that guarantee robustness and satisfy performance requirements for a particular task.

Novel Guidance, Navigation and Control Concepts

Flight control system design is transitioning from cut-and-try techniques for single-input single- output frequency based techniques to multi-input multi-output optimization problems based in the time domain. Research on AI-based technology in the form of expert systems coupled with neural networks for flight control design and on-line implementation to provide on-line adaptive control are being performed. A new means of accurate and reliable attitude and heading determination based on based on Global Navigation Satellite (GPS) system concepts to achieve flight accuracy requirements is highly desirable. A key objective for this element is to demonstrate feasibility of real-time state estimation via GPS-based interferometric techniques.



 
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