Robust feedback control of combustion instability with modeling uncertainty

This paper presents the design of a robust feedback controller for suppressing combustion instabilities in propulsion systems with distributed actuators. The control synthesis procedure is based on the H_∞-optimization, which guarantees robust stability and performance within specified uncertainty bounds by taking into account the effects of unmodeled dynamics, sensor noise, and parametric errors. It makes use of an observer structure for robust estimation of combustion dynamics, and an H_∞ loop-shaping for performance requirements. Results of simulation experiments are presented to show how longitudinal pressure oscillations can be suppressed in a generic combustion chamber. The closed-loop control system exhibits robust stability and performance in the presence of exogenous disturbances and parametric errors.