L1 adaptive output feedback augmentation of Model Reference Control

This paper presents an L₁ adaptive output feedback augmentation of a Model Reference Controller for a class of unknown single-input single-output, linear time-invariant systems. Similar to prior solutions in L₁ adaptive control theory, the feedback structure consists of a predictor, adaptation laws and a low-pass filter. The closed-loop system achieves arbitrarily close tracking of the input and the output signals of the reference system. The proposed control strategy has been implemented and simulated on a longitudinal autopilot for a missile model. Simulation results show the performance of the adaptive control law in the presence of parameter uncertainties and input disturbance.