Proxy control barrier functions: Integrating barrier-based and Lyapunov-based safety-critical control design

• Published in: Automatica (Oxford) Vol. 178; p. 112364
• Main Authors: Wang, Yujie, Xu, Xiangru
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2025
• Subjects: Control barrier function; Safety-critical control; Strict-feedback system; Uncertain system; Uncertain system; Control barrier function; Safety-critical control; Strict-feedback system
• ISSN: 0005-1098
• DOI: 10.1016/j.automatica.2025.112364

This work introduces a novel Proxy Control Barrier Function (PCBF) scheme that integrates barrier-based and Lyapunov-based safety-critical control strategies for strict-feedback systems with potentially unknown dynamics. The proposed method employs a modular design procedure, decomposing the original system into a proxy subsystem and a virtual tracking subsystem that are controlled by the control barrier function (CBF)-based and Lyapunov-based controllers, respectively. By integrating these separately designed controllers, the overall system’s safety is ensured. Moreover, a new filter-based disturbance observer is utilized to design a PCBF-based safe controller for strict-feedback systems subject to mismatched disturbances. This approach broadens the class of systems to which CBF-based methods can be applied and significantly simplifies CBF construction by requiring only the model of the proxy subsystem. The effectiveness of the proposed method is demonstrated through numerical simulations.