Formal modeling and control of cyber-physical manufacturing systems

Cyber-physical manufacturing systems are a new paradigm of manufacturing systems that integrate cyber systems and physical systems to aid smart manufacturing. Cyber-physical manufacturing systems can improve agility and responsiveness and guarantee the quality of products to meet the market requirements. Meanwhile, cyber-physical manufacturing systems also become susceptible to cyber-attacks. In order to improve the trustworthiness of cyber-physical manufacturing systems in the dynamic modeling phase, a cyber-physical manufacturing system formal model based on object-oriented Petri nets is presented from the perspective of multi-agent systems. Some mathematical methods and supporting tools of Petri nets can be utilized to analyze, verify, and validate cyber-physical manufacturing system formal model. To defense the malicious software spreading in cyber-physical manufacturing systems at run-time, a spreading dynamics model is proposed, and its dynamic behaviors are analyzed. A hybrid bifurcation control method is designed to control the Hopf bifurcation that is caused by the malicious software spreading. The simulation results show that the hybrid bifurcation control method can make cyber-physical manufacturing systems generate the expected dynamic behaviors and guarantee the trustworthiness of cyber-physical manufacturing systems at run-time.