Work

A Model-Free Approach to Control Barrier Functions Using Funnel Control

Year: 2025

Type: article

Abstract: Control barrier functions (CBFs) are a popular approach to design feedback laws that achieve safety guarantees for nonlinear systems. The CBF-based controller design relies on the availability of a model to select feasible inputs from the set of CBF-based controls. In this paper, we develop a model-free approach to design CBF-based control laws, eliminating the need for knowledge of system dynamics or parameters. Specifically, we address safety requirements characterized by a time-varying distance to a reference trajectory in the output space and construct a CBF that depends only on the measured output. Utilizing this particular CBF, we determine a subset of CBF-based controls without relying on a model of the dynamics by using techniques from funnel control. The latter is a model-free high-gain adaptive control methodology, which achieves tracking guarantees via reactive feedback. In this paper, we discover and establish a connection between the modular controller synthesis via zeroing CBFs and model-free reactive feedback. The theoretical results are illustrated by a numerical simulation.

Source: IEEE Control Systems Letters

DOI: 10.1109/lcsys.2025.3581519

Authors: Lukas Lanza, Johannes Köhler, Dario Dennstädt, Thomas Berger, Karl Worthmann

Institutions: Technische Universität Ilmenau, Paderborn University, ETH Zurich, Institute for Dynamic Systems and Control

Language: English

Topic: Adaptive Control of Nonlinear Systems

Subfield: Control and Systems Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,645

Funder: Deutsche Forschungsgemeinschaft