Polynomial LPV synthesis applied to turbofan engines

Results on polynomial fixed-order controller design are extended to SISO gain-scheduling with guaranteed stability and H∞H∞ performance over the whole scheduling parameter range. Salient features of the approach are: (a) the use of polynomials as modeling objects; (b) the use of flexible linear matrix inequalities (LMI) conditions allowing polynomial dependence of the open-loop system and controller transfer functions in the scheduling parameters; and (c) the decoupling in the LMI conditions between the Lyapunov variables and the controller variables, allowing both parameter-dependent Lyapunov functions and fixed-order controller design. The synthesis procedure is integrated into the ATOL framework developed by the manufacturer of aircraft and space engines Snecma to systematically design reduced complexity gain-scheduled control laws for aircraft turbofan engines.