Implementation of a closed-loop structural control system using wireless sensor networks

Wireless sensor networks have rapidly matured in recent years to offer data acquisition capabilities on par with those of traditional tethered data acquisition systems. Entire structural monitoring systems assembled from wireless sensors have proven to be low-cost, easy to install and accurate. However, the functionality of wireless sensors can be further extended to include actuation capabilities. Wireless sensors capable of actuating a structure could serve as building blocks of future generations of structural control systems. In this study, a wireless sensor prototype capable of data acquisition, computational analysis and actuation is proposed for use in a real-time structural control system. The performance of a wireless control system is illustrated using a full-scale structure controlled by a semi-active magnetorheological (MR) damper and a network of wireless sensors. One wireless sensor designated as a controller automates the task of collecting state data, calculating control forces, and issuing commands to the MR damper, all in real-time. Additional wireless sensors are installed to measure the acceleration and velocity response of each system degree-of-freedom. Base motion is applied to the structure to simulate seismic excitations while the wireless control system mitigates inter-story drift response of the structure. An optimal linear quadratic regulation (LQR) solution is formulated for embedment within the computational cores of the wireless sensors.