Adaptive control of uncertain nonlinear aircraft systems using combined linearized models

This paper proposes a new adaptive control scheme for uncertain non-canonical nonlinear aircraft systems, which expands the capacity of linearization-based adaptive control from local to semi-global. Local linearization-based design has been used for adaptive control of non-canonical nonlinear aircraft systems, due to certain desired capacity to handle complexity of non-canonical aircraft system dynamics for which most existing nonlinear control methods are not applicable. As a benchmark study, this paper addresses a general longitudinal dynamic motion of rigid aircraft systems in a non-canonical form with unparametrizable uncertainties. A semi-global linearization-based control method is developed for such aircraft systems by constructing a new reparametrization procedure based on T-S fuzzy system approximation using local linearized models and a relative degree formulation, and then developing an adaptive controller to ensure closed-loop stability and asymptotic output tracking for T-S fuzzy approximation aircraft systems. Simulation results verify the effectiveness of the proposed control scheme.