Title: Scalable Decentralized Control over Ad Hoc Sensor-Actuator Networks Summary: This project studies the extent to which ad hoc networks of sensors and actuators may be used to implement large-scale feedback control systems. Dense ad hoc networks suffer from significant capacity limitations that suggest scalability may only be achieved if we restrict ourselves to localized network traffic patterns. Moreover, such sensor-actuator networks have a large number of clients sharing the same communication channel, so that contention between different clients will greatly reduce the amount of data that can be streamed between sensors and actuators. Maintain- ing specified levels of overall control system performance in such a non-deterministic environment is extremely challenging and we feel that it can only be achieved if we adopt a cross-layer approach in which application (i.e., control) algorithms and networking protocols are intimately aware of each others capabilities and limitations. This project investigates fundamental relationships between control system performance and network quality-of-service (QoS). The project will use these rela- tionships to develop decentralized control algorithms and supporting network middleware services that can guarantee application (control) performance over extremely large ad hoc sensor-actuator networks. The intellectual merit of the proposed work lies in its precise characterization of the way in which network middleware impacts control system performance. The project will demon- strate these algorithms and services on a physical testbed in which a spatially-distributed physical plant is controlled in a decentralized manner over an ad hoc radio (RF) network of embedded processors. The project's broader impacts will be felt through its impact on undergraduate education at Notre Dame as well as through on-going collaborations with civil, environmental, and mechanical engineering researchers both in and out of Notre Dame. In particular, the project's proposed testbed will be tied to undergraduate courses in electrical and mechanical engineering, thereby providing students with a novel opportunity to contribute to an on-going research program. Moreover we are collaborating with civil/environmental engineers to develop sensor-actuator networks that can address the combined-sewer overfow (CSO) problem faced by a number of municipalities across the Midwest and Eastern United States. The results from this project have the potential to reduce anticipated costs associated with solving the CSO problem. The results from this project will therefore have a broad societal impact extending well beyond the immediate project objectives.
