A rigorous approach to the design of resilient cyber-physical systems through co-simulation

Abstract

The engineering of resilient cyber-physical systems requires collaborative development and analysis of models from different disciplines, including discrete-event models of software and continuous-time models of physical plant. This paper describes a rigorous approach to the model-based design of such systems through co-simulation of discrete-event models in the Vienna Development Method (VDM) and continuous-time models in 20-sim. These are coupled by a co-simulation tool that coordinates the execution of the models in their respective simulators. Co-models can be augmented with descriptions of potential failures and fault tolerance mechanisms, allowing early stage evaluation of alternatives before a commitment is made to realising functionality in the cyber or physical side. We describe the content of an emerging methodology for co-model development, co-simulation and design space exploration, presenting a case study and two examples from the library of design patterns developed for this setting.