Realistic Case Studies of Wireless Structural Control
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 stateof-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 Girardeau bridge over the Mississippi
River and wireless traces collected from a similar bridge
(the Jindo Bridge) in South Korea. These case studies shed light
on the challenges of WSC and the limitations of a traditional structural
control approach 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.