Robust stabilization of axial flow compressors with uncertain pressure-flow maps

In this paper we develop globally robustly stabilizing controllers for rotating stall and surge in multimode axial flow compressor models with uncertain pressure-flow compressor performance characteristic maps. Specifically, using Lyapunov stability theory, a novel switching nonlinear globally robustly stabilizing control law based on equilibria-dependent Lyapunov functions with converging domains of attraction is developed. The locus of the equilibrium points on which the equilibria-dependent Lyapunov functions are predicated is characterized by the axisymmetric stable pressure-flow equilibrium branch of the nominal compression system. The proposed robust nonlinear control framework is directly applicable to uncertain compression systems with actuator amplitude and rate saturation constraints while providing a guaranteed domain of attraction. An application to a two-mode axial flow compressor with an uncertain pressure-flow map and rate saturation control constraints is presented.