WCPS: Wireless Cyber-Physical Simulator

WCPS: Wireless Cyber-Physical Simulator

Wireless Structural Control (WSC) systems can play a crucial role in protecting civil infrastructure in the events of earth quakes and other natural disasters. Such systems represent an exemplary class of cyber-physical systems that perform close-loop control using real-time sensor data collected through wireless sensor networks. Existing WSC research usually employ wireless sensors installed on small lab structures, which cannot capture realistic delays and data loss in wireless sensor networks deployed on large civil structures and their impacts on structural control. The lack of realistic studies and tools that capture both the cyber (wireless) and physical (structures) aspects of WSC systems represent a hurdle for cyber-physical systems research for civil infrastructure. This paper advances the state of the art of WSC and Cyber-physical System 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 matching 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 Girardeau bridge over the Mississippi River and wireless traces collected from a similar bridge (the Jindo Bridge) in Korea. These case studies shed lights on the challenges of WSC and the limitations of a traditional structural controller under realistic wireless conditions. Finally, we proposed a cyber-physical co-design approach to WSC that integrates a novel holistic scheduling scheme (for sensing, communication and control) and an Optimal Time Delay Controller (OTDC) that substantially improves structural control performance.

Wireless Network Modeling in WCPS

Example

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Simulink Modeling in WCPS

Example

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WSC Examples with WCPS

Wireless Building Control

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Wireless Bridge Control

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References

• B. Li, Z. Sun, K. Mechitov, G. Hackmann, C. Lu, S. Dyke, G. Agha and B. Spencer, "Realistic Case Studies of Wireless Structural Control," ACM/IEEE International Conference on Cyber-Physical Systems (ICCPS'13), April 2013.

• Z. Sun, B. Li, S.J. Dyke and C. Lu, "Evaluation of Performances of Structural Control Benchmark Problem with Time Delays from Wireless Sensor Network," Joint Conference of the Engineering Mechanics Institute and ASCE Joint Specialty Conference on Probabilistic Mechanics and Structural Reliability (EMI/PMC'12), June 2012.

• H. Lee, A. Cerpa, and P. Levis. Improving wireless simulation through noise modeling. In IPSN, 2007.

• P. Levis, N. Lee, M. Welsh, and D. Culler. Tossim: Accurate and scalable simulation of entire tinyos applications. In Sensys, 2003.