Distributed Data Processing and Real-Time Control using Wireless Sensor Networks

Professor Jerome P. Lynch

University of Michigan

Department of Civil and Environmental Engineering

Department of Electrical Engineering and

Computer Science

Abstract The common deterioration of civil infrastructure systems and the threat of extreme loadings require facility managers to improve their knowledge regarding the health of the structures that they manage. A dense array of wireless sensors installed in a structure could provide ample amounts of empirical data for monitoring structural health. In addition to being a low cost alternative to traditional cable-based monitoring systems, wireless sensor networks offer a distributed computing paradigm that allows sensors to self interrogate structural response data in real-time. Various field validation studies have been performed using wireless sensor network architectures under development at the University of Michigan. The Geumdang Bridge (Icheon, South Korea) is monitored using a dense network of wireless sensors. Sensors are responsible for recording the response of the bridge to traffic loading. Furthermore, the wireless sensor network conducts in-network system identification analyses to estimate modal parameters of the bridge.

In recent years, substantial research has been conducted to advance structural control as a direct means of mitigating the dynamic response of civil structures. To reduce the labor and costs associated with installing extensive lengths of coaxial wires in today’s structural control systems, wireless sensors are being considered as building blocks of future systems. In the proposed system, wireless sensors are designed to perform three major tasks in the control system; wireless sensors are responsible for the collection of structural response data, calculation of control forces, and issuing commands to actuators. In this study, a wireless sensor is designed to fulfill these tasks explicitly. However, the demands of the control system, namely the need to respond in real-time, push the limits of current wireless sensor technology. The wireless channel can introduce delay in the communication of data between wireless sensors; in some rare instances, outright data loss can be experienced. To validate the performance of a prototype wireless control system, shaking table experiments are carried out on a half-scale three story steel structure in which a magnetorheological (MR) damper is installed for real-time control. In comparison to a cable-based control system installed in the same structure, the performance of the WiSSCon system is shown to be effective and reliable.

Friday, March 24, 2006

3:30 – 4:30 p.m.

1500 EECS