L₁ adaptive augmented dynamic inversion controller for a high agility UAV

This paper presents an £1 adaptive controller with piecewise-constant adaptation law augmenting a dynamic inversion PI error controller for the FSD ExtremeStar, a high agility UAV with a large number of control devices. A three axis nonlinear dynamic inversion controller serves as the baseline controller for this architecture with roll-rate, pitch-rate and yaw-rate as inner loop command inputs. The outer loop of the controller is driven by the same type of commands, but it interposes a maneuver coordination and attitude correction before passing the signals to the inner loop. The state predictor of the £1 architecture is modified in order to prevent the attempt of adaptive compensation of system inherent physical limitations. This paper first presents the baseline controller followed by a thorough description of the £1 adaptive controller. Results are presented via a full-scale, nonlinear simulation of the FSD ExtremeStar under adverse conditions.