Fixed-order robust control for a engine based on Homotopy algorithm

Focus on a turbo-engine, the significant shortcomings of H_∞,H_∞/H₂ and μ control are given. A new design method of fixed order mixed μ controller for turbofan engine is presented. Fixed order H_∞/H₂ controller is designed by the use of a canonical controller construction form. Existent necessary conditions for an optimal fixed order H_∞/H₂ controller are derived. The Homotopy algorithm is used to obtain the solution of an optimal fixed order H_∞/H₂ controller. A different control strategy of obtaining fixed order mixed μ controller is proposed that fixed order H_∞/H₂ controller incorporated into a mixed μ synthesis procedure. Comparison with a full order design, fixed order mixed μ controller reduces controller complexity and achieves robust performance levels similar to full order design. The approach proposed is applied to turbo-engine fixed-order mixed μ controller design. The simulation results show that the robustness of controlled system performance is satisfied.