Wireless Cyber-Physical Simulator and Case Studies on Structural Control

Abstract: Wireless Structural Control (WSC) systems can play a crucial role in protecting civil infrastructure in the event of earthquakes and other natural disasters. Such systems represent an exemplary class of cyber-physical systems that perform close-loop control using wireless sensor networks. Existing WSC research usually employs wireless sensors installed on small lab structures, which cannot capture realistic delays and data loss in wireless sensor networks deployed on large civil structures. The lack of realistic tools that capture both the cyber (wireless) and physical (structural) aspects of WSC systems has been a hurdle for cyber-physical systems research for civil infrastructure. This advances the state of the art through the following contributions. First, we developed the Wireless Cyber-Physical Simulator (WCPS), an integrated environment that combines realistic simulations of both wireless sensor networks and structures. WCPS integrates Simulink and TOSSIM, a state-of-the-art sensor network simulator featuring a realistic wireless model seeded by signal traces. Second, we performed two realistic case studies each combining a structural model with wireless traces collected from real-world environments. The building study combines a benchmark building model and wireless traces collected from a multi-story building. The bridge study combines the structural model of the Cape Girardea

Cyber-Physical Co-Design of Wireless Control Systems

Wireless sensor-actuator network (WSAN) technology is gaining rapid adoption in process industries because of its advantages in lowering deployment and maintenance cost in challenging environments. While early success of industrial WSANs has been recognized, significant potential remains in exploring WSANs as unified networks for industrial plants. This thesis research explores a cyber-physical co-design approach to design wireless control systems. To enable holistic studies of wireless control systems, we have developed the Wireless Cyber-Physical Simulator (WCPS), an integrated co-simulation environment that integrates Simulink and our implementation of WSANs based on the industrial WirelessHART standard. We further develop novel WSAN protocols tailored for advanced control designs for networked control systems. WCPS now works as the first simulator that features both linear and nonlinear physical plant models, state-of-art WirelessHART protocol stack, and realistic wireless network characteristics. A realistic wireless structural control study sheds light on the challenges of WSC and the limitations of a traditional structural control approach under realistic wireless conditions. Systematic emergency control results demonstrate that our real-time emergency communication approach enables timely emergency handling, while allowing regular feedback control loops to effectively share resources in WSANs during normal operations. A co-joint study of wireless routing and control highlights the importance of the co-design approach of wireless networks and control

Distributed Sensing for High Quality Structural Health Monitoring Using Wireless Sensor Networks

Abstract—In recent years, using wireless sensor networks (WSNs) for structural health monitoring (SHM) has attracted increasing attention. Traditional centralized SHM algorithms developed by civil engineers can achieve the highest damage detection quality since they have the raw data from all the sensor nodes. However, directly implementing these algorithms in a typical WSN is impractical considering the large amount of data transmissions and extensive computations required. Correspondingly, many SHM algorithms have been tailored for WSNs to become distributed and less complicated. However, the modified algorithms usually cannot achieve the same damage detection quality of the original centralized counterparts. In this paper, we select a classical SHM algorithm: the eigen-system realization algorithm (ERA), and propose a distributed version for WSNs. In this approach, the required computations in the ERA are updated incrementally along a path constructed from the deployed sensor nodes. This distributed version is able to achieve the same quality of the original ERA using much smaller wireless transmissions and computations. The efficacy of the proposed approach is demonstrated through both simulation and experiment. I