Luenberger Observer-Based Flight Controller Design Using Robust Control Toolbox™

This paper presents a design example of structured H-infinity, control-based flight controller for the lateral-directional motions of JAXA's research airplane MuPAL-alpha using MATLAB (R) Robust Control Toolbox (TM). To be more specific, the design problem of Luenberger observer-based flight controllers is addressed. Even if the controllers' structure is a priori supposed and fixed as Luenberger observer-based controllers, it does not always hold true that the controllers' states faithfully estimate the plants' states. We thus adopt two-step design approach to realize good control performance and good plants' states estimation simultaneously, viz., we first optimize H-infinity control performance of the closed-loop system, and then optimize H-infinity, observer performance under slightly relaxed H-infinity, control performance constraint. In the second process, systune command is used, because multiple design requirements are simultaneously imposed. The control and observer performance are both examined by the Hardware-In-the-Loop Simulation (HILS) tests using the actual MuPAL-alpha.