document: Linear , parameter-varying control and its application to a turbofan engine This paper describes application of parameter-dependent control design methods to a turbofan engine . Parameter-dependent systems are linear systems , whose state-space descriptions are known functions of time-varying parameters . The time variation of each of the parameters is not known in advance , but is assumed to be measurable in real-time . Three linear , parameter-varying -LRB- LPV -RRB- approaches to control design are discussed . The first method is based on linear fractional transformations which relies on the small gain theorem for bounds on performance and robustness . The other methods make use of either a single -LRB- SQLF -RRB- or parameter-dependent -LRB- PDQLF -RRB- quadratic Lyapunov function to bound the achievable level of performance . The latter two techniques are used to synthesize controllers for a high-performance turbofan engine . A LPV model of the turbofan engine is constructed from Jacobian linearizations at fixed power codes for control design . The control problem is formulated as a model matching problem in the H/sub infinity / and LPV framework . The objective is decoupled command response of the closed-loop system to pressure and rotor speed requests . The performance of linear , H/sub infinity / point designs are compared with the SQLF and PDQLF controllers . Nonlinear simulations indicate that the controller synthesized using the SQLF approach is slightly more conservative than the PDQLF controller . Nonlinear simulations with the SQLF and PDQLF controllers show very robust designs that achieve all desired performance objectives
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