Piardi, LuísCosta, PedroOliveira, André Schneider deLeitão, Paulo2025-06-272025-06-272025Piardi, Luís; Costa, Pedro; Oliveira, André Schneider de; Leitão, Paulo. (2025). Collaborative fault tolerance for cyber-physical systems: The Diagnosis Stage. IEEE Access. ISSN 2169-3536. 13, p. 37278- 372892169-3536http://hdl.handle.net/10198/34626The reliability and robustness of cyber-physical systems (CPS) are critical aspects of the current industrial landscape. The high level of autonomous and distributed components associated with a large number of devices makes CPS prone to faults. Despite their importance and benefits, traditional fault tolerance methodologies, namely local and/or centralized, often overlook the potential benefits of collaboration between cyber-physical components. This paper introduces a collaborative fault diagnosis methodology for CPS, integrating self-fault diagnosis capabilities in agents and leveraging collaborative behavior to enhance fault diagnosis. The contribution of this paper relay in propose a methodology for fault diagnosis for CPS, based on multi-agent system (MAS) technology as a backbone of infra-structure, highlighting the components, agent behavior, functionalities, and interaction protocols, to explore the benefits of communication and collaboration between agents. The proposed methodology enhance the accuracy of fault diagnosis when compared with local approach. A case study was conducted in a laboratory- scale warehouse, focusing on diagnosing drift, bias, and precision faults in temperature and humidity sensors. Experimental results reveal that the collaborative methodology significantly outperforms the local approach in fault diagnosis, as evidenced by performance improvements in diagnosis classification. The statistical significance of these results was validated using the Wilcoxon signed-ranks test for paired samples.engFault diagnosisCyber-physical systemMulti-agent systemCollaborationFault tolerancejournal article10.1109/access.2025.3543081