Uncertainty Modeling and Robustness Analysis of Flight Control Using m -Analysis Techniques

Flight control systems are often designed in linearization points over a flight envelope and it must be proven to clearance authorities that the system works for different parameter variations and failures all over the envelope. A numerical matrix-based robustness analysis method using -analysis techniques is described herein. The method contains three key steps: 1) convert the nonlinear system of aircraft with uncertainty into a linear parameter varying (LPV) system, 2) convert the LPV system into a linear fractional transformation (LFT) system, 3) analysis. Uncertainty modeling methods are presented: include overview of LPV modeling, quasi-LPV modeling by function substitution method and approach to formulation of LPV models near bifurcation points; and then two software tools for computing LFT model from LPV model are introduced. Finally, an example is given to illuminate the sound of this recommended method.