Emerging cyber-physical systems (CPS) such as smart industrial production lines, smart energy grids, and autonomous vehicular systems are characterized by multiple feedback control loops that are closed over a shared communication channel. This poses new challenges for the communication and control system design to support such networked control systems (NCS) with stringent real-time requirements. Network design has to move from traditional throughput-oriented optimization of network resources to real-time orientation to support NCS. Control systems in turn need to become aware of the changing conditions and opportunities of the network infrastructure. A strictly separate design is known to lead to high conservatism and thus to a low quality of control and to low efficiency and high cost in the context of resource usage. So, future CPS design needs to address control and networking jointly to efficiently fulfill the tight control performance requirements. Today, there exists no systematic approach for the joint design of the control and communication protocol.
The objective of this project is to develop a framework for the co-design of communication and control, concretely for the optimal co-design of the wireless resource management in terms of medium access control and networked multi-loop control. Our key contributions are (1) a deep understanding of the relationship between the achievable control performance, communication network parameters and control system parameters based on analytic models, (2) novel optimal control and scheduling designs under resource constraints, (3) novel mechanisms for medium access in multi-hop wireless networks with real-time requirements, and (4) a (near-) optimal layering architecture and co-design for wireless communication and control over wireless multi-hop networks. We take the scenario of multiple independent control loops accessing one shared wireless communication channel as our starting point. In particular, we consider control systems with heterogeneous linear time invariant processes and a typical wireless network medium access control based on a slotted aloha principle. We investigate the wireless network resource management and control performance trade-off, propose new models for a joint consideration and explore their fundamental limits in terms of scale and performance. Based on the decomposition of the overall optimization problem, we will derive a novel approach for the control and scheduling design as well as new network resource management schemes to support a co-design. We will provide a first optimal system co-design through the solution of the decomposed optimization problem. A key focus is put on finding fundamental results. Preliminary findings of a joint work of the two proposers' collaborating research groups suggest a high benefit from the joint modelling and co-design strategies.
- Fundamental joint modeling and analysis of control processes & medium access mechanisms
- Analysis and decomposition of the optimization problem
- Design of event-triggered control with awareness of communication medium
- Design of new control-aware resource allocation mechanisms
- Control and communication co-design based on joint optimization variable set