Semi-active Control of Tunable Hybrid Shape Memory Material for Vibration Attenuation
Vibration absorber has been used as an effective tool in the vibration reduction of structure-suffered single-frequency excitation. An absorber consisted of a spring element made of hybrid shape memory materials was proposed. A cantilevered beam fabricate
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Abstract Vibration absorber has been used as an effective tool in the vibration reduction of structure-suffered single-frequency excitation. An absorber consisted of a spring element made of hybrid shape memory materials was proposed. A cantilevered beam fabricated by superelastic (SE) core and shape memory polymer (SMP) sleeves was employed as the spring element of the absorber. By controlling the electric current through the SE core and thereby the temperature of the SMP sleeves, the natural frequency of the absorber was tunable. In this study, an absorber with actively tunable frequency capability may offer more powerful solution. The fabricated hybrid shape memory material absorber was capable of changing its natural frequency by more than 45 %. By applying semi-active controllers including fuzzy logic control and self-tuning control to the tunable vibration absorber, system resonance can be avoided, thus ensuring adaptability and robustness of the damping system. Keywords Semi-active control • Shape memory material • Vibration attenuation
1 Introduction The operation of precision machinery may encounter vibration problem when under external force excitation. Therefore vibration control is crucial in improving the machine precision level and keeping steady-state operation for manufacturing; the product yield rate thus can be increased. To solve the vibration problem, one can apply a passive control method, such as redesigning the system so that the structure natural frequency is far away from the excitation frequency, in order to avoid the
J. Shaw (*) • J.-D. Huang Institute of Mechatronic Engineering, National Taipei University of Technology, Taipei 10608, Taiwan e-mail: [email protected] J. Juang and Y.-C. Huang (eds.), Intelligent Technologies and Engineering Systems, Lecture Notes in Electrical Engineering 234, DOI 10.1007/978-1-4614-6747-2_100, # Springer Science+Business Media New York 2013
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resonance phenomenon, or employing a vibration absorber [1] to minimize the main structural vibration; one can use an active control method, for example, adding an actuator in the system to provide a counter force [2]; and one can employ a semiactive control method, such as using MR (magnetorheological fluid) mount [3] or adjustable vibration absorber [4], by varying the control input based on the applied excitation frequency to adjust the system parameters (stiffness/damping ratio, etc.) so that vibration attenuations can be achieved. Sun et al. [5] and Williams et al. [6] surveyed some adjustable vibration absorber design methods including adjustable shape memory alloy (SMA) vibration absorber. Williams et al. [4, 6, 7] used SMA for an adjustable vibration absorber and can tune the absorber frequency up to 17 % change by applying varying electric currents to the absorber. Chen [8] designed a cantilevered beam made of superelastic (SE) SMA core and shape memory polymer (SMP) sleeves as a vibration absorber. Experiments showed that this adjustable hybrid shape memory material vibr
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