Vibration control of a beam using linear magnetostrictive actuators

摘要

Terfenol-D is one of magnetostrictive materials with the property of converting the energy in magnetic field into mechanical motion, and vice versa. We designed and fabricated a linear magnetostrictive actuator using Terfenol-D as a control device. In order to grasp the dynamic characteristics of the actuator, a series of experimental and numerical tests were performed. Induced-strain actuation displacements of the actuator measured by the test and predicted by magnetic analysis agreed well. And blocked forces according to the input currents were estimated from the testing results. Modeling method representing the exerting force of the actuator was confirmed through some testing results. We also explored the effectiveness of the linear magnetostrictive actuator as a structural control device. A series of numerical and experimental tests was carried out with simple aluminum beam only supported at each end by the actuator. After the equation of motion of the controlled system was obtained by the finite element method, a model reduction was performed to reduce the numbers of degree of freedom. A linear quadratic feedback controller was realized on a real-time digital control system to damp the first four elastic modes of the beam. Through some tests, we confirmed the possibility of the actuator for controlling beam-like structures.