Enhancing Incremental NDI Control with L1 Adaptive Augmentation in a Longitudinal Autopilot

In this work the effectiveness of an adaptive control augmentation for high-performance fixed-wing aircraft is investigated. An Incremental Nonlinear Dynamic Inversion (INDI) pitch rate control loop is designed within the cascade of a longitudinal autopilot. A minimally invasive ℒ1-adaptive controller is then designed to counteract system uncertainties and variations, with an hedging procedure that ensures bounded adaptation during saturation events. A time-domain performance analysis is performed, showing that the baseline INDI controller draws a clear benefit from the ℒ1-adaptive augmentation.