Structural vibration mitigation of slender engineering structures is investigated using the example of a monopile-supported wind turbine tower studied through a scaled model of the NREL 5 MW reference turbine. The proposed solution employs a hybrid magnetorheological tuned vibration absorber (TVA) installed in the nacelle, targeting the dominant tower bending mode governing the vibration response and stress distribution. The main contribution of the study is the development of enhanced optimal control strategies based on maximum principle–derived nonlinear control and LQR formulations. These strategies are augmented with newly introduced quality terms that explicitly limit active force demands to account for practical actuator implementation. By penalising high-frequency acceleration-related actuation, the proposed control framework reduces actuator power demand and TVA stroke requirements. The control strategies are validated experimentally under harmonic excitation and scaled stochastic forces derived from OpenFAST-simulated rotor thrust and hydrodynamic load time histories. The stochastic excitation combines IEC 1-ED3 turbulent wind with irregular wave loading represented by a Pierson–Moskowitz spectrum. The experimental results confirm the intended control behaviour relative to baseline configurations. The proposed approach is formulated for real-time implementation and provides a framework for full-scale vibration-mitigation design based on dynamic-similarity criteria. The research project was supported by the program “Excellence initiative–research university” for the AGH University. The laboratory equipment was partially supported by the AGH University's Subsidy, Research Task 14808.
Paweł Martynowicz (Thu,) studied this question.