A comprehensive control strategy for integrated flight/propulsion systems

Abstract

Integration of flight and propulsion control systems in advanced aircraft has attracted much attention because of ever increasing demand on enhancement of performance and reliability. As the underlying dynamic couplings and non-linear interactions of flight and propulsion systems are too complex for realtime execution in onboard computational platforms, hierarchical hybrid (i.e. combined continuously varying and discrete event) architecture is proposed for the development of future generation control systems that will take the advantage of these interactions for mission enhancement. Although the original structures of continuously varying control systems for propulsion and flight are retained, discrete event supervisory (DES) control would facilitate decision-making for aircraft operation. DES decisions regarding propulsion and flight control influence the performance and reliability of the entire vehicle control system due to interactions at the level of continuously varying dynamics. A two-level hierarchical DES control system is designed to supervise and coordinate the operation of twin-engine aircraft propulsion with flight dynamics. In essence, the propulsion system is integrated with the flight dynamical system such that the DES controller at the propulsion level of hierarchy provides load balancing of the engines as well as overall health and mission management of the aircraft propulsion system. The parameter-scheduling dynamic-inversion controller stabilizes and drives the flight system in the vehicle operation envelope and compensates for potential unbalance and any other undesirable action, resulting from discrete event supervision of the propulsion system. Results of real-time simulation on a test bed are presented to demonstrate the efficacy of the proposed control concept.