Browsing by Author "Shin, Jong-Yeob"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Blending Methodology of Linear Parameter Varying Control Synthesis of F16 Aircraft System(American Institute of Aeronautics and Astronautics, 2002) Shin, Jong-Yeob; Balas, Gary J.; Kaya, M. AlpayThe design of a linear parameter varying (LPV) controller for the F-16 longitudinal axes over the entire flight envelope, using a blending methodology that lets an LPV controller preserve regional optimal solutions over each parameter subset and reduces computational costs for synthesizing an LPV controller, is presented. Three blending LPV controller synthesis methodologies are applied to control F-16 longitudinal axes. By the use of a function substitution method, a quasi-LPV model of the F-16 longitudinal axes is constructed from the nonlinear equations of motion over the entire flight envelope, including nontrim regions, to facilitate synthesis of LPV controllers for the F-16 aircraft. The nonlinear simulations of the blended LPV controller show that the desired performance and robustness objectives are achieved across all altitude variations.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.