Reduced Order and Prioritized Reference Governors for Limit Protection in Aircraft Gas Turbine Engines

Abstract

This paper considers the application of the reduced order and prioritized reference governors to protect aircraft gas turbine engines against constraint violation. The aircraft gas turbine engine control system must enforce various constraints that protect the engine from surge, over-speed, over-temperature and combustion blowout conditions, while satisfying actuator magnitude and rate limits. The reference governor is an add-on scheme augmented to a nominal engine controller, that modifies set-points that the nominal controller responds to if there is a danger of constraint violation. Prioritized reference governors enforce hard constraints and soft constraints in the order of their priority in cases when strictly enforcing all the constraints is infeasible. The reduced order reference governor theory facilitates the rigorous design of reference governors based on reduced order models so that the constraints are satisfied by the full order system. Simulation results based on a gas turbine engine model are reported that illustrate constraint handling using prioritized and reduced order reference governor techniques.