A novel simulation strategy for equation-based models of cyber-physical systems

Cyber-physical systems (CPS) is a complex intelligent system consists of discrete asynchronous information and continuous synchronous physical systems that are different in structure and mathematics basis. In this article, a new simulation strategy for CPS model is explored based on the equation-based modeling language Modelica. Firstly, some new semantics, such as Clock, Sampling and Holding, are proposed to model information systems based on Modelica. Secondly, the serialization method is proposed to separate the information equation systems from CPS model and sequence the information and physical equation systems respectively. Thirdly, the unified simulation method, which consists of information system simulation strategy and unified simulation strategy, is present to solve the CPS model in a unified form. An inverted pendulum system is taken to demonstrate the above methods. Differently from the common modeling methods and simulation strategy, where the information system and physical system are modeled and simulated separately in different tools and then linked with interfaces between these tools. The major novelty of proposed strategy is that the CPS model could be built and simulated in a unified framework and the information system and physical system could be linked automatically in a natural way.