LMI based multivariable H_∞ fixed-order control for an aeroengine

A design method of multivariable static output feedback H_∞ fixed-order PI controller for aeroengine is presented. The synthesis of H_∞ fixed-order controller can be formulated as a bilinear matrix inequality (BMI) optimization problem which is hard to solve. Under certain aeroengine conditions, the BMI raised in the H_∞ fixed-order design problem can be converted into standard linear matrix inequality (LMI). The existence condition of H_∞ fixed-order controller is deduced and the design procedure of the controller is proposed. The proposed method has been applied to the fixed-order PI controller design of a turbofan engine. The simulation results show that the performance and robustness of the control system are satisfactory.