22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-4.10.R1

THE DESIGN OF AN AUTOMATIC FLIGHT CONTROL SYSTEM FOR A HYPERSONIC TRANSPORT AIRCRAFT

D. McLean (1), Z. Zaludin (2)
(1) University of Southampton, UK; (2) Universiti Putra, Malaysia

Keywords: hypersonic transport aircraft, aircraft dynamics, stability, automatic flight control system, mathematical model

The design of an automatic flight control system for a hypersonic transport aircraft (HST) is presented. It uses a mathematical model of the longitudinal motion of an HST flying at Mach 8.0 and at a height of 85000 feet. Included in the model were the non-linear dynamics associated with the propulsion system. Since the basic aircraft is dynamically unstable, closedloop stabilization was required. Normally, the required degree of closed-loop stability is determined from published flying qualities specifications which are unavailable, however, for this type of aircraft. Consequently, a set of dynamic parameters for the closed-loop stabilization system was proposed which corresponded with notionally acceptable flying qualities. Using these parameters it was possible to use an analytical procedure to determine a corresponding state weighting matrix to be used in a quadratic performance index which, when minimized, provided a feedback control law that ensured the controlled HST had the specified flying qualities. The effectiveness of the system is demonstrated from results obtained by digital simulation, including the propulsion system.

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