Browsing by Author "Fialho, Ian"

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    Gain-Scheduled Lateral Control of the F-14 Aircraft during Powered Approach Landing
    (American Institute of Aeronautics and Astronautics, 2000) Fialho, Ian; Balas, Gary J.; Packard, Andrew K.; Renfrow, Joseph; Mullaney, Chris
    The design of a linear fractional transformation gain-scheduled controller, scheduled on angle of attack, for the F-14 aircraft lateral-directional axis is presented. The controller is designed for the powered approach flight phase, during which the angle of attack and corresponding airspeed varies from 2 deg and 182 kn to 14 deg and 126 kn. A linear fractional model of the lateral dynamics is constructed based on four linearized models that correspond to 2, 6, 10.5, and 14 deg angle of attack. Using parameter-dependent functions, a controller is designed that depends in a linear fractional manner on angle of attack and delivers uniform handling quality over angle-of-attack variations that lie between 2–14 deg. The resulting controller performs well when implemented in a nonlinear simulation model of the F-14 aircraft.
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    Road Adaptive Active Suspension Design using Linear Parameter-Varying Gain-Scheduling
    (Institute of Electrical and Electronic Engineers, 2002-01) Fialho, Ian; Balas, Gary J.
    This paper presents a novel approach to the design of road adaptive active suspensions via a combination of linear parameter-varying control and nonlinear backstepping techniques. Two levels of adaptation are considered: the lower level control design shapes the nonlinear characteristics of the vehicle suspension as a function of road conditions, while the higher level design involves adaptive switching between these different nonlinear characteristics, based on the road conditions. A quarter car suspension model with a nonlinear dynamic model of the hydraulic actuator is employed. Suspension deflection, car body acceleration, hydraulic pressure drop, and spool valve displacement are used as feedback signals. Nonlinear simulations show that these adaptive suspension controllers provide superior passenger comfort over the whole range of road conditions.