Reduced Order Modal-Space Wireless Control of Civil Engineering Structures

Abstract

Semi-active actuators are capable of providing control forces to reject unwanted vibrations due to wind or seismic effects in civil structural systems by affecting strategic modifications to structural properties (e.g. stiffness or damping). Such devices enjoy the advantage of being low-cost and low-power (compared to active devices), and are inherently stable, however limitations on the magnitudes of their achievable output forces necessitate the use of numerous (distributed) semiactive devices in order to be effective. Coordination of large, decentralized networks is a natural task for wireless networks given their adaptability and low-cost to install. Low-power wireless sensor nodes are capable of sensing, communication, computation of control forces (using for example, state feedback and state estimation), and issuing commands due to their inherent collocated computing power. However, their relatively low computational speed adds undesirable latency to the control system as models grow large. In this study, a low-order model based on modal condensation is used within a wireless control network to reduce seismically induced vibrations within a six-story steel structure. Tradeoffs between model size and control latency are explored. Both simulation and experimental results are presented.