%0 Journal Article
%T Comparison of Analog and Digital Self-Powered Systems in Multimodal Vibration Suppression
%A Shigeru Shimose
%A Kanjuro Makihara
%A Junjiro Onoda
%J Smart Materials Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/287128
%X This paper compares our analog and digital self-powered systems for vibration suppression, and shows experimental results of multimodal vibration suppression for both self-powered systems. The experimental results are evaluated in light of the damping performance and adaptability under various vibrational conditions. We demonstrate various examples of our innovative vibration suppression method, called ¡°digital self-powered.¡± Proper status switching of an electric circuit made up of an inductor and a selective switch connected to a piezoelectric transducer attenuates the vibrations. The control logic calculation and the switching events are performed with a digital microprocessor that is driven by the electrical energy converted from the mechanical vibration energy. Therefore, this vibration suppression system runs without any external power supply. The self-powering feature makes this suppression method useful in various applications. To realize an ideal vibration suppression system that is both self-powered and effective in suppressing multimode vibration, sophisticated control logic is implemented in the digital microprocessor. We demonstrate that our digital self-powered system can reduce the vibrational displacements of a randomly excited multimodal structure, by as much as 35.5%. 1. Introduction Vibration control methods are roughly categorized into two groups, that is, active and passive methods [1¨C4]. Active vibration control methods usually yield high-performance vibration suppression [1, 2]. However, active control systems may become unstable if the control is improperly designed. In addition, active vibration control systems need an external energy supply to suppress vibrations. On the other hand, passive vibration control methods use energy dissipative mechanisms such as dampers, frictional devices, and electric resistors [3, 4]. Because passive approaches do not need an energy supply they are always stable. Passive methods are easier to implement in actual systems than are the more complicated active methods, because they do not need controllers, sensors, or filters. However, in most cases, passive systems do not provide a satisfactory vibration suppression performance. In general, the majority of passive systems suppress vibrations well only in expected situations such as those regarding natural frequency and temperature. Typical examples of less robustness of frequency alternation are mechanically tuned mass dampers and electrical dynamic vibration absorbers. There are research papers that compare the performance of semiactive and passive
%U http://www.hindawi.com/journals/smr/2012/287128/