NeTS: Small: Towards Efficient and Reliable Communication Infrastructure for Network Controlled Cyber Physical Systems with Application in Smart Grids

智能电网、无人机和机器人网络等典型的网络物理系统(CPSS)由物理动力学、传感器、通信网络和控制器组成。通信网络将系统测量数据从传感器传输到控制器，在CPSS中扮演着关键角色，类似于人类的神经系统。传统的数据通信网络(例如，蜂窝网络或WiFi)只关注数据分组的传送，而CPS的最终目标是控制物理动态(例如，稳定电力网络中的电压和频率)。因此，在CPSS的背景下，由于设计目标的不匹配，传统的通信网络设计可能不是最优的。这就迫切需要对CPSS中的通信网络设计进行研究，以提高CPSS的灵活性、健壮性和效率。该项目研究如何有效地为CPS设计系统动力学感知的通信网络，它集成了通信、网络、控制和动态系统领域，并应用于关键基础设施中CPS的重要和不断发展的领域。本项目具体研究了以下研究任务：(A)作为混合系统的联合设计：利用混杂系统理论对CPS进行建模，其中通信网络的运行模式被建模为混杂系统的离散状态，而物理动态被建模为连续状态。通信和控制子系统通过优化混合系统动力学进行联合设计；(B)信息接口分离设计：通信和控制子系统分别设计，并通过指定的接口连接，如通信服务质量(Qos)或虚拟队列映射；(C)与弹性数据业务共存：实时数据业务可以与互联网数据等弹性数据业务共享相同的通信资源。将弹性数据流量的排队动态和CPS的物理动态集成在同一个框架中，研究了弹性流量和实时流量的调度问题；(D)智能电网的应用与实现：以CPS为例，将前面两个任务中得到的原理、算法和协议在智能电网中进行了应用和验证。重点研究了微电网中的电压集中控制和分散控制。它们分别在通信和控制子系统协同仿真的软件仿真试验台、使用USRP板卡的硬件试验台和微电网试验台上实现。

Typical cyber physical systems (CPSs), such as smart grid, unmanned aerial vehicles (UAVs) and robotic networks, consist of physical dynamics, sensors, communication network and controllers. The Communication network, which conveys system measurements from sensors to controllers, plays a key role in CPSs, similarly to the nerve system in human beings. Traditional data communication networks (e.g., cellular networks or WiFi) focus only the delivery of data packets, while the ultimate goal of a CPS is to control the physical dynamics (e.g., stabilizing the voltages and frequencies in power networks). Hence, the traditional design of communication network may not be optimal in the context of CPSs, due to the mismatched goals of designs. This results in a pressing need to study the design of communication networks in CPSs, which helps to enhance the agility, robustness and efficiency of CPSs. This project studies how to efficiently design system-dynamics-aware communication networks for CPS, which integrates the areas of communications, networking, control, and dynamical systems, and has applications to the important and growing field of CPS in critical infrastructures.The project specifically addresses the following research tasks: (a) Joint Design as Hybrid Systems: The theory of hybrid systems is used to model CPS, in which the operation mode of communication network is modeled as the discrete state of a hybrid system, while the physical dynamics are modeled using the continuous state. The communication and control sub-systems are designed jointly by optimizing the hybrid system dynamics; (b) Separate Design via Information Interface: The communication and control sub-systems are designed separately and are bridged via designated interfaces, such as communication quality of service (QoS) or virtual queue mapping; (c) Coexistence with Elastic Data Traffics: The realtime data traffic may share the same communication resource with elastic data traffics such as Internet data. The queuing dynamics of elastic data traffic and the physical dynamics of CPS are integrated in the same framework, and the scheduling for the two types of traffics (elastic and realtime) is studied; (d) Application and Implementation in Smart Grid: The principles, algorithms, and protocols obtained in the previous two tasks are applied and substantiated in smart grids as a case study for CPS. The voltage control in microgrid, both centralized and decentralized, is particularly studied. They are implemented in both software simulation testbed, in which the communication and control sub-systems are co-simulated, and hardware testbed using USRP boards and the microgrid testbed.