Robust feedback control of combustion instability with modeling uncertainty

This paper presents the design of a robust feedback controller for suppress ing combustion instabilities in propulsion systems with distributed actuato rs. The control synthesis procedure is based on the H-infinity-optimization , which guarantees robust stability and performance within specified uncert ainty bounds by taking into account the effects of unmodeled dynamics, sens or noise, and parametric errors. It makes use of an observer structure for robust estimation of combustion dynamics, and an H-infinity loop-shaping fo r performance requirements. Results of simulation experiments are presented to show how longitudinal pressure oscillations can be suppressed in a gene ric combustion chamber. The closed-loop control system exhibits robust stab ility and performance in the presence of exogenous disturbances and paramet ric errors. (C) 1999 by The Combustion Institute.