Nonlinear Adaptive Dynamic Inversion Control for Variable Stability Small Unmanned Aircraft Systems

Abstract

In-flight simulation and variable stability aircraft provide useful capabilities for flight controls development such as testing control laws for new aircraft earlier, identification of adverse conditions such as pilot-induced oscillations, and handling qualities research. While these capabilities are useful they are not without cost. The expense and support activities needed to safely operate in-flight simulators has limited their availability to military test pilot schools and a few private companies. Modern computing power allows the implementation of advanced flight control systems on size, weight, and power constrained platforms such as small uninhabited aerial systems used by universities and research organizations. This thesis aims to develop a flight control system that brings in-flight simulation capability to these platforms. Two control systems based on model reference and L₁ adaptive augmentation of baseline nonlinear dynamic inversion controllers are proposed and evaluated against a command augmentation system design and in-flight simulation cases for a variety of linear and nonlinear models. Simulation results demonstrate that both proposed control architectures are able to meet the control objectives for tracking and in-flight simulation and performance and stability robustness in the presence of severe turbulence.