This paper considers the problem of output feedback control for non-square multi-input multi-output systems with arbitrary relative degree. The proposed controller, based on the L1 adaptive control architecture, is designed using the right interactor matrix and a suitably defined projection matrix. A state-output predictor, a low-pass filter, and adaptive laws are introduced that achieve output tracking of a desired reference signal. It is shown that the proposed control strategy guarantees closed-loop stability with arbitrarily small steady-state errors. The transient performance in the presence of non-zero initialization errors is quantified in terms of decreasing functions. Rigorous mathematical analysis and illustrative examples are provided to validate the theoretical claims.
@article{arxiv.1901.07427,
title = {L1 Adaptive Output Feedback for Non-square Systems with Arbitrary Relative Degree},
author = {Hanmin Lee and Venanzio Cichella and Naira Hovakimyan},
journal= {arXiv preprint arXiv:1901.07427},
year = {2024}
}