Turbofan engine control design using robust multivariable control technologies

A unified robust multivariabIe approach to propulsion control design has re cently been developed at National Aeronautics and Space Administration (NAS A) Glenn Research Center (GRC). The critical elements of this unified appro ach are 1) a robust H-infinity control synthesis formulation; 2) a simplifi ed controller scheduling scheme; and 3) a new approach to the synthesis of integrator windup protection gains for multivariable controllers, This pape r presents results from an application of these technologies to control des ign for linear models of an advanced turbofan engine. The objectives of the study were to transfer technology to industry and to identify areas of fur ther development for the technology to be applied by industry to the design of practical controllers for high-performance turbofan engines, The techno logy elements and industrial development of tools to implement the steps ar e described with respect to their application to a GE variable-cycle turbof an engine. A set of three-input/three-output three-state linear engine mode ls was used over a range of power levels covering engine operation from idl e to maximum unaugmented power. Results from simulation evaluation of H-inf inity controller design, controller order reduction, controller scheduling, and integrator windup protection design are discussed and insight is provi ded into how the design parameter choices affect the results.