REFLEXES: A Co-Designed Architecture for In-Network Control

传感、通信、控制和计算领域的最新进展催生了一类新兴的复杂应用，称为网络物理系统(CPS)。因此，过程不再局限于特定的单一设备，而是通过通信网络相互连接的几个相互依赖的节点之间进行协调。CPS正在进入越来越多的领域，如工业自动化、能源、交通和医疗。CPS的部署具有显著的好处，包括更高的灵活性、效率和适应性。然而，传统的分离和分层的通信和控制体系结构阻碍了CPS的普遍采用，由于通信引起的不可靠和延迟损害了控制质量，甚至可能导致危险行为。本项目的目标是开发一种新的共同设计的通信和控制体系结构，以便在可用通信和计算资源的情况下使CP具有最佳的性能。我们的核心概念在本质上有一个类比：在身体内，反射是位于脊髓中的快速、预先定义的、简单的动作模式，即接近(在低延迟的意义上)传感器和执行器。更高级的计划和控制机制位于较远的大脑中。在我们项目的第一阶段，我们引入了网络内控制的新范例，它通过利用主动网络组件的(有限的)计算能力使控制功能尽可能地接近过程来反映自然反射。我们已经证明，当网络是可靠的并且传感器读数和控制器信号之间的关系很简单时，这可以显著提高控制质量。对于第二阶段，我们的目标是将我们的方法扩展到更现实的场景。我们专注于提高无线控制系统的可靠性和网络中的高级处理功能，这两者都是现实世界部署的基础。我们将在控制器设计中考虑针对不确定系统的高级稳健控制机制，包括更复杂的信号处理，考虑到网络单元有限的计算能力和无线通信引起的延迟。为了允许确定性控制器执行，我们将利用空间协作来在无线信道受损时保持低控制消息延迟。因此，我们避免了闭合控制环路中不必要的延迟和不可靠性，从而产生了显著更好的控制质量。反射的关键方法论贡献在于：(I)在给定的通信和计算基础设施上分配控制的新方法，包括用于性能评估的适当分析工具；(Ii)通过以单一和全新的方法共同设计控制和通信过程，用于实时约束下的网络内处理的新软件框架。

Recent advances in sensing, communication, control, and computation have fostered an emerging class of complex applications, called Cyber-Physical Systems (CPS).Therein, processes are no longer bound to specific single devices but coordinated between several interdependent nodes interconnected via communication networks.CPS are making inroads into an increasing number of domains such as industrial automation, energy, transport, and healthcare.The deployment of CPS promises considerable benefits, including increased flexibility, efficiency, and adaptability.However, the traditional separate and layered design of communication and control architectures prevents the ubiquitous adoption of CPS, as communication-induced unreliability and latencies compromise the quality-of-control and may even lead to dangerous behavior.The goal of this project is to develop a novel co-designed architecture for communication and control to enable the best possible performance of CPS given the available communication and computation resources.Our core concept has an analogy in nature: Within the body, reflexes are fast, pre-defined, simple action patterns located in the spinal cord, i.e., close (in the sense of low latencies) to the sensors and actuators.Higher-level planning and control mechanisms are located farther away in the brain.In phase I of our project, we introduced the novel paradigm of in-network control, which mirrors natural reflexes by allowing to push control functionalities as close as possible to a process by leveraging the (limited) computational power of active network components.We have shown that this significantly improves the quality-of-control when networks are reliable and relations between sensor readings and controller signals are simple.For phase II, we aim at extending our approach to more realistic scenarios.We focus on increasing the reliability of wireless control systems and on advanced processing functionalities within the network, both fundamental to real-world deployments.We will consider advanced robust control mechanisms for uncertain systems in controller design, including more complex signal processing, taking into account the limited computational power of in-network elements and the delay induced by wireless communication.To allow deterministic controller execution, we will harness spatial cooperation to maintain low control message latencies also when wireless channels are impaired.We thus avoid unnecessary latencies and unreliability within closed control loops, yielding significantly better quality-of-control.The key methodical contributions of REFLEXES are (i) a novel approach to distribute control on a given communication and computation infrastructure including appropriate analysis tools for performance evaluation, and (ii) a novel software framework for in-network processing under real-time constraints by co-designing control and communication procedures in a single and fundamentally new methodology.