東京大学 · 工学
Suzuki教授の研究室では、マイクロマシンセンサーやエネルギーハーベスティングデバイスの開発を柱として、MEMS技術を応用した高効率な電磁気的エネルギー変換素子の研究が進められています。特に、電極材料としてのエレクトレットを用いた静電的浮上構造や、バイステーブルな力学的特性を有するエネルギー変換素子の設計・実装に注力しており、人の運動から得られる微小エネルギーを効率的に回収する技術の実現を目指しています。また、液体中や大気中を問わず安定に動作する静電的リーブィング機構の実証も進んでいます。
Figures are computed from collected data and may differ slightly.
Abstract Energy harvesting is a method by which energy naturally present in the environment is captured and then converted into electricity for use in low‐power electronics. Among the various energy sources, structural vibration is believed to be useful for powering wireless sensors in various applications such as sensor network and structural health monitoring. In the present paper, after a brief introduction to electret materials and charging technologies, recent progress in microelectromechan
In this paper, we propose a passive gap-spacing control method in order to avoid stiction between top and bottom structures in in-plane sensor/actuator/generator applications. A patterned electret using a high-performance perfluoro polymer material is employed to induce a repulsive electrostatic force. An out-of-plane repulsive force is successfully demonstrated with our early prototype, in both air and liquid. By using the present electret-based levitation method to keep the air gap, a MEMS ele
The structure of a turbulent flowfield along a riblet surface was investigated with the aid of a three-dimensional particle tracking velocimetry. The statistics of all three velocity components were measured and compared with those above a smooth wall. Under a drag-reducing condition, all of the turbulent velocity fluctuations and the Reynolds shear stress were decreased near the riblet surface, although the flow characteristics in most of the flowfield were quite similar to those above the smoo
This paper reports the development of MEMS rotational electret energy harvester (EH) for capturing kinetic energy of human motion. Optimal design method of rotational electret EH is proposed by considering both the rate of overlapping-area-change and the parasitic capacitance. A rotational MEMS electret EH with embedded ball bearing has been successfully developed. Up to 3.6 μW has been obtained at 1 rps rotation with an early prototype.
A MEMS electret vibration energy harvester with an embedded bistable electrostatic spring for broadband response is proposed. By using a vertical electret, the bistable potential can be realized without any complex structure or additional mechanism. Based on the 1D electrostatic model, a rigorous electromechanical model as well as an approximate model with reduced parameters are developed. Based on the normalized expression of the approximate model, which is identical to the velocity-damped reso
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