Wireless communication and embedded computation are key enabling technologies for future autonomous systems. Embedded devices allow for gathering and processing data in remote and distributed locations, while wireless multi-hop networks offer unprecedented flexibility in sharing data between these devices, for example, to increase collective information or take collaborative action. The term cyber-physical system (CPS) emphasizes the tight integration of computation and communication with physical processes as a key characteristic of these systems. Possible applications are numerous and include, for example:
- Autonomous cars sharing information to enable adaptive traffic control reducing fuel consumption and traffic jams;
- Controlling factory automation machinery over a wireless network replacing the cabling of traditional systems;
- A swarm of quadcopters flying in formation and coordinating their actions in a rescue mission.
While distributed computation and wireless networking show great promise for designing future CPSs, significant challenges must be overcome to realize their full potential:
- Closing feedback loops over wireless (multi-hop) links require robustness of the control against network imperfections such as delays and packet drops.
- When multiple loops are closed over the same network, communication becomes a shared and limited resource that must be managed for optimal system operation.
- In order to realize energy savings and optimal system-level performance, control and communication systems must be designed in tandem taking mutual constraints and inter-dependencies into account.
This project takes up these challenges and targets the joint design and integration of distributed event-based control and low-power wireless networking to demonstrate tangible benefits over traditional isolated designs in terms of, for example, superior performance, unprecedented flexibility, and resource savings. In particular, we seek to demonstrate:
- Feasibility of operating a CPS across a multi-hop low-power wireless network;
- Integrated design: control system informs communication system in real-time about feedback requirements;
- Benefits of event-based control design over traditional periodic control.
The developed design and algorithms will be evaluated on a real-world CPS demonstrator (see above figure), which involves multiple unstable, spatially distributed physical processes being controlled over a multi-hop low-power wireless network.
Current research activities within this project focus on the development of novel triggering mechanisms for event-based state estimation to allow for the integration with the communication system [ ], stability guarantees respecting the specific network characteristics, and integration on the hardware demonstrator.
Research in this project is in collaboration with the Networked Embedded Systems Group at TU Dresden (Dr. Marco Zimmerling, Fabian Mager) within a joint DFG grant.