Experimental validation of novel structural control algorithms is a vital step in both developing and building acceptance for this technology. Small-scale experimental test-beds fulfill an important role in the validation of multiple-degree-offreedom (MDOF) and distributed semi-active control systems, allowing researchers to test the control algorithms, communication topologies, and timing-critical aspects of structural control systems that do not require full-scale specimens. In addition, small-scale building specimens can be useful in combined structural health monitoring (SHM) and LQG control studies, diminishing safety concerns during experiments by using benchtop-scale rather than largescale specimens. Development of such small-scale test-beds is hampered by difficulties in actuator construction. In order to be a useful analog to full-scale structures, actuators for small-scale test-beds should exhibit similar features and limitations as their full-scale counterparts. In particular, semi-active devices, such as magneto-rheological (MR) fluid dampers, with limited authority (versus active mass dampers) and nonlinear behavior are difficult to mimic over small force scales due to issues related to fluid containment and friction. In this study, a novel extraction-type small-force (0- 10 N) MR-fluid damper which exhibits nonlinear hysteresis similar to a full-scale, MR-device is proposed. This actuator is a key development to enable the function of a small-scale structural control test-bed intended for wireless control validation studies. Experimental validation of this prototype is conducted using a 3-story scale structure subjected to simulated single-axis seismic excitation. The actuator affects the structural response commanded by a control computer that executes an LQG state feedback control law and a modified Bouc-Wen lookup table that was previously developed for full-scale MR-applications. In addition, damper dynamic limitations are characterized and presented including force output magnitude and frequency characteristics.

Date Published: 27 March 2015
PDF: 14 pages
Proc. SPIE 9435, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2015, 943511 (27 March 2015); doi: 10.1117/12.2082715

Published in SPIE Proceedings Vol. 9435:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2015
Jerome P. Lynch, Editor(s)