Two-Layer Adaptive Funnel MRAC with Applications to the Control of Multi-Rotor UAVs

This paper merges for the first time two recent forms of adaptive control techniques, namely two-layer model reference adaptive control (MRAC) and funnel control, also known as tube-based control. Two-layer MRAC allows the user to set the rate of convergence of the tracking error arbitrarily high without altering the user-defined reference model or relying on barrier functions. Funnel control is a technique whereby the tracking error is constrained within bounds that can be progressively tighter. The proposed approach merges the benefits of both techniques and, for the first time in the literature on funnel control, explicitly regulates the diameter of the funnel through some user-defined adaptive law. The proposed results are tested by simulating payload delivery missions using multi-rotor unmanned aerial vehicles (UAVs) in the high-fidelity environment PyChrono.