System Identification of a 200 kN Magneto-Rheological Fluid Damper for Structural Control in Large-Scale Smart Structures

This paper presents a hyperbolic tangent model to capture the salient dynamic behavior of large-scale 200 kN magneto-rheological (MR) fluid dampers. The damper model will be used for simulation studies of the effectiveness of semiactive control for seismic protection as well as for controller design and diagnostic tests for large-scale real-time testing of the MR dampers at the University of Colorado at Boulder (CU) fast hybrid test (FHT) facility. A series of sinusoidal tests are conducted at the CU FHT facility for varying frequencies, amplitudes, and constant control current levels to determine the parameters of the hyperbolic tangent model as functions of current. Finally, the simulated damper force from the MR damper model is compared to that of the physical MR dampers subjected to random excitation and random control current. The hyperbolic tangent model is observed to predict closely the experimentally obtained MR damper forces over a wide dynamic range and within the constraints of computation time and fixed integration time step required for real-time diagnostic tests utilizing the CU FHT system.