NONLINEAR RECONFIGURABLE FLIGHT CONTROL SYSTEM USING MULTIPLE MODEL ADAPTIVE CONTROL

In this study, adaptive control methodology using multiple models is proposed to design a reconfigurable controller for nonlinear systems. An adaptive model and fixed parameter models are used for mode switching, and a re-initialized adaptive model is considered. The conventional mode switching method based on multiple model adaptive control does not guarantee the stability of the closed-loop system. To improve the adaptiveness of a nonlinear system while maintaining the stability, mode switching scheme is modified and a new decision logic is considered. In the mode switching control scheme, forgetting factor and adaptive time concepts are introduced based on the selected model for reconfiguration. An error threshold value is used in the decision logic. Numerical simulation is performed for a nonlinear discrete-time MIMO aircraft system to verify the effectiveness of the proposed method.