Distributed Virtual Time-Based Synchronization for Simulation of Cyber-Physical Systems
提出一种结合分布式物理硬件与仿真模型的信息物理系统测试平台，核心是分布式虚拟时间系统，通过两种同步模式实现嵌入式设备间低开销、高精度的虚拟时钟同步，并在电网控制应用中验证其有效性。
Our world today increasingly relies on the orchestration of digital and physical systems to ensure the successful operations of many complex and critical infrastructures. Simulation-based testbeds are useful tools for engineering those cyber-physical systems and evaluating their efficiency, security, and resilience. In this article, we present a cyber-physical system testing platform combining distributed physical computing and networking hardware and simulation models. A core component is the distributed virtual time system that enables the efficient synchronization of virtual clocks among distributed embedded Linux devices. Virtual clocks also enable high-fidelity experimentation by interrupting real and emulated cyber-physical applications to inject offline simulation data. We design and implement two modes of the distributed virtual time: periodic mode for scheduling repetitive events like sensor device measurements, and dynamic mode for on-demand interrupt-based synchronization. We also analyze the performance of both approaches to synchronization including overhead, accuracy, and error introduced from each approach. By interconnecting the embedded devices’ general purpose IO pins, they can coordinate and synchronize with low overhead, under 50 microseconds for eight processes across four embedded Linux devices. Finally, we demonstrate the usability of our testbed and the differences between both approaches in a power grid control application.