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

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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.