Experimental Assessment of a Frequency Adaptive Feedback Mechanism for a Three-Dimensional Structural System Including Perturbation

The performance of any control mechanism degrades in practice due to the deviation of the structural system and the frequency regime of the excitation to the initial form. This study experimentally investigated the effectiveness of a frequency adaptive control strategy for a three-dimensional structural system when subjected to control input. Initially, the control was designed in the independent modal space of a generalized symmetric structural system to control the lateral degrees of freedom. A closed-loop experimental study was performed on a scaled symmetric single-story frame structure based on frequency adaptive control for a low, near-resonance, and high-frequency sinusoidal excitation with respect to the fundamental natural frequency of the symmetric system. The performance of the proposed frequency adaptive control was compared with respect to the existing linear quadratic Gaussian (LQG) control strategy. In a later stage, a perturbed structural system was considered and controlled with the same control input designed for the symmetric system subjected to sinusoidal excitations. The structural responses were evaluated in terms of lateral and torsional modes of vibrations for the controlled symmetric and perturbed structural systems with respect to the uncontrolled system behavior based on the adopted control mechanism along with the existing LQG control.