Multi-Domain Modeling through Specification of a Domain Specific Modeling Language for Cyber-Physical Systems Development

Abstract

Cyber-Physical Systems pair discrete-event computational components with physical components--like electronic circuits--which are governed by continuous-time dynamics. If we are able to simultaneously model the computational and physical aspects of a system, then we could drastically shorten timelines for such systems by being able to simulate, evaluate, and formally verify integrated system behavior all prior to the costly phase of system deployment. Model simulations allow designers to test safety critical use scenarios, and can form a basis for system parameterization. In this work, we present the Signal Flow Domain Specific Modeling Language (DSML) which serves as a free and open language for describing synchronous control logic within the Embedded Systems Modeling Language Framework (ESMoL) and the Cyber-Physical Systems Modeling Language (CyPhyML). Signal Flow is adept at modeling software processes, and its functional blocks are math functions which reference underlying C-code snippets. Furthermore, Signal Flow models can synthesize deployable C-code, for use within the target hardware platform. We describe the use of Signal Flow within CyPhyML for integrating the computational and physical components of a bidirectional DC/DC converter intended for use in a hybrid vehicle. The full system was modeled in CyPhyML with the vehicle controller employing the Signal Flow DSML. All possible converter mode transitions are composed and simulated as testbenches, and their results illustrate expected system behavior with the controller working seamlessly with the physical circuit model.