Trustworthiness Modeling and Analysis of Cyber-physical Manufacturing Systems

Cyber-physical manufacturing systems (CPMSs) are a new paradigm of manufacturing systems that integrate cyber systems and physical systems to aid smart manufacturing. CPMSs can improve the system's flexibility and productivity and adapt to new market demands. However, CPMSs are susceptible to cyber-attacks, which can modify manufacturing intents to produce parts incorrectly and cause hazards to equipment, employees, and consumers. Therefore, the trustworthiness of CPMSs is critical to the entire systems. In order to describe and analyze the trustworthiness of CPMSs, generalized stochastic Petri nets are adopted to model CPMSs and the trustworthiness is measured from three metrics, i.e., the reliability, availability and security. To study the trustworthiness evolution of CPMSs, a malicious software spreading dynamics model is presented, and its dynamic behaviors are analyzed. Finally, the CPMS trustworthiness evolution model is constructed depending on the proposed dynamics model. The simulation results demonstrate that the proposed approach is effective to model and analyze the CPMS trustworthiness.