Browsing by Author "Packard, Andrew K."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Control of the F-14 Aircraft Lateral-Directional Axis during Powered Approach(American Institute of Aeronautics and Astronautics, 1998) Balas, Gary J.; Packard, Andrew K.; Renfrow, Joseph; Mullaney, Chris; M'Closkey, Robert T.The design of linear controllers for the F-14 aircraft lateral-directional axis during powered approach using the structured singular-value (μ) framework is presented. Controllers are designed for an angle of attack of 10.5 deg and an airspeed of 137 kn, the on-speed flight condition. Each controller is implemented in a simplified nonlinear simulation and the full-order Fortran nonlinear simulation of the F-14. Pilot-in-the-loop simulations are used to verify their performance in the crewed flight simulator at the U.S. Naval Air Warfare Center, Patuxent River, Maryland. The μ controllers out perform the current analog and newly developed digital lateral-directional powered approach flight control system in pilot-in-the-loop simulations.Item 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, ChrisThe 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.Item Worst-Case Analysis of the X-38 Crew Return Vehicle Flight Control System(American Institute of Aeronautics and Astronautics, 2001) Shin, Jong-Yeob; Balas, Gary J.; Packard, Andrew K.A linear fractional transformation (LFT) model of the linearized equation of the lateral-directional axes of the X-38 crew return vehicle is developed to facilitate the analysis of flight control systems. The LFT model represents uncertainty in nine aerodynamic stability derivatives at a given flight condition with frequency-domain performance specifications. The X-38 LFT model combined with a controller at specific flight conditions is used to determine the aerodynamic coefficients that result in the worst-case performance and gain/phase margin of the closed-loop system. The objective is to verify that a given controller remains stable and achieves desired performance objectives for all predefined aerodynamic variations at select operating conditions along its flight trajectory.