Robust Nonlinear Control of Stall and Flutter in Aeroengines

Petar Kokotovic (Project Coordinator), A. H. Epstein, E. M. Grietzer,
A. J. Krener, R. M. Murray, C. N. Nett, J. D. Paduano

This AFOSR-PRET Center assembles a team of researchers in nonlinear control theory (University of California and Caltech) and in compressor unsteady dynamics (MIT) to develop and test new techniques for robust nonlinear control of aeroengine instabilities, specifically compression system rotating stall and surge, and compressor blade flutter. The program coordinates the scientific base and proven approaches for dynamical analysis and control of rotating stall and surge developed at United Technologies Research Center (UTRC) and MIT with new robust nonlinear control design techniques developed at UC Santa Barbara, UC Davis, and Caltech.

This integrated effort has two primary goals: 1) to generalize and advance robust nonlinear control theory by applying it to real-world aeroengine instability issues, thus establishing a ``fast-track'' for transitioning relevant design techniques and software to industry, and 2) to generalize and apply proven nonlinear dynamics and control concepts used for rotating stall and surge control to an important new arena: active control of turbomachine aeromechanical instabilities (flutter). The outcomes envisioned are new and practicable avenues for improving reliability, operability, and performance of both military and civil gas turbine engines through use of robust nonlinear control.

While the required elements for successful research and transition are addressed in detail in the text, several points about the unique qualities of this team deserve mention. UTRC is committed to playing a central role in both the research and transition process. It will contribute significant technical leadership and experimental facilities, make its data and results available to the university partners, and implement key results in an industrial setting. The coordinating site is the Center for Control Engineering and Computation at UC Santa Barbara. Its established record of engendering communication between control researchers and engineers will enhance visibility and transition of results to the broad control community in both academia and industry. This transition is further strengthened by the expertise of UC Davis in nonlinear control software and by Caltech's commitment to laboratory demonstration of nonlinear control. Exposure of students to both experimental and industrial applications is ensured through a ``ladder'' of experiments which proceeds from university laboratories to high-speed industrial facilities at UTRC. Finally, the strong and sustained relationship between MIT, UTRC, and Pratt & Whitney , as well as MIT's compressor unsteady modeling and control expertise, underpin the overall technical program.

Richard Murray (
Last modified: Sat May 13 17:56:21 1995