A low-complexity funnel control approach for non-linear systems of higher-order

We address the problem of output reference tracking for unknown non-linear multi-input, multi-output systems described by functional differential equations. This class of systems includes those with a strict relative degree, and bounded-input bounded-output (BIBO) stable internal dynamics. The objective is to ensure that the tracking error evolves within a prescribed performance funnel. To achieve this, we propose a novel model-free adaptive controller with lower complexity than existing funnel control methods, avoiding the use of non-linearities in intermediate error signals. We establish the feasibility and effectiveness of the proposed design through theoretical analysis and demonstrate its performance with simulations, comparing it to previous approaches.