Funnel control with input filter for nonlinear systems of relative degree two

TL;DR

This paper introduces a model-free adaptive funnel control method with an output filter for nonlinear systems of relative degree two, ensuring prescribed tracking performance without output derivatives.

Contribution

It presents a novel adaptive funnel controller that guarantees output tracking in unknown nonlinear systems of relative degree two, avoiding derivative computations.

Findings

Controller ensures tracking within prescribed funnel boundaries

No derivative of output needed for control implementation

Validated through a numerical example

Abstract

We address the problem of output reference tracking for unknown nonlinear multi-input, multi-output systems with relative degree two and bounded-input bounded-state (BIBS) stable internal dynamics. We propose a novel model-free adaptive controller that ensures the evolution of the tracking error within prescribed performance funnel boundaries. By applying an output filter, the control objective is achieved without utilizing derivative information of system's output. The controller is illustrated by a numerical example.