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This research study proposes a new active control structure to suppress vibrations of a small-scale wind turbine blade with attached magnetorheological fluid patch actuated by an electromagnet. The blade structure is manufactured by an aluminum extrusion machine considering the airfoil data of SH3055 which is designed for use on a small wind turbine. An interaction model between the magnetorheological patch and the electromagnetic actuator is derived and a force characterization is realized. A norm-based multiobjective H2/H∞ controller is designed using the state-space model of the elastic blade element. The H2/H∞ controller is experimentally implemented under the steady-state aerodynamic load conditions. The results of experiments show that the magnetorheological layer patch is effective for suppressing vibrations of the blade structure and robust against parametric uncertainty.

The aim of this research is to attenuate the vibrations of a blade structure with an attached piezoelectric actuator using robust multi-objective control. The force obtained from a piezoelectric patch loading has uncertainties due to the complicated shape (airfoil) of the blade element. A parameter-dependent model of the force equation is developed to understand the possible variation range of the actuation force. The modal analysis of the blade is performed to find vibration mode frequencies, and an aerodynamic load is generated experimentally to create steady-state vibration on the blade. A state-space model is obtained by considering certain vibration modes and the parameter-dependent part of the force in the input vector is taken outside of the plant model. The robust stability filter is modified with parameter dependency to have a cluster of the filter. Two different multi-objective controllers are designed with different design objectives. The designed controllers are implemented in experiments and performances of the controllers are compared using frequency and time domain responses. It is shown that the flexible blade vibrations are successfully suppressed with the proposed mixed norm robust controllers under the effect of steady-state aerodynamic disturbance with different air speeds. It is observed in experimental results that the performances of the [Formula: see text] controller are better than the [Formula: see text] controller.

This research study proposes a new active control structure to suppress vibrations of a small-scale wind turbine blade filled with magnetorheological (MR) fluid and actuated by an electromagnet. The aluminum blade structure is manufactured using the SH3055 (Bergey Windpower Co. Inc., Norman, OK, USA) code numbered airfoil which is designed for use on small wind turbines. A dynamic interaction model between the MR fluid and the electromagnetic actuator is constructed to obtain a force relation. A detailed characterization study is presented for the proposed actuator to understand the nonlinear behavior of the electromagnetic force. A norm based multi-objective H2/H∞ controller is designed using the model of the elastic blade element. The H2/H∞ controller is experimentally implemented under the impact and steady state aerodynamic load conditions. The results of experiments show that the MR fluid- electromagnetic actuator is effective for suppressing vibrations of the blade structure.

This study examined the control performance of a multi-layer smart beam structure in which the middle layer was partially filled with magnetorheological (MR) fluid. A galloping profile was connected to the endpoint to obtain vibration from this smart beam element in a regular regime. Flow-induced continuous vibration was created on the beam element by giving wind load from a certain distance to this galloping profile. The natural frequency values of the smart beam element were obtained analytically using the lumped parameter mathematical model, and their accuracy was compared with numerical methods. An electromagnet was placed opposite to MR fluid region to suppress vibrations by creating an actuator relationship with the smart beam. A norm-based H∞ robust control design was realized by taking the natural frequencies of the beam element into account. The control design was applied to the experimental system and the effectiveness of the controller was tested under various conditions. It was observed that the proposed MR fluid embedded active control structure has good properties to suppress the wind-induced vibrations in practice.