The University of Tokyo · 공학
유지지 교수의 연구실은 마이크로전자기기(MEMS) 기반의 에너지 수확 기술에 초점을 맞추고 있으며, 주로 인간 운동이나 구조물의 진동에서 발생하는 미세 에너지를 전기로 변환하는 소자 개발을 핵심 연구 방향으로 삼고 있습니다. 특히 전기장이 유지되는 전기절연체(일명 엘렉트릿)를 활용한 비접촉식 레벨링 구조나 이중상태 전기 스프링을 통한 넓은 대역응답 특성을 확보한 MEMS 에너지 허버를 개발하고 있습니다. 연구는 실용적 응용을 고려해 무선 센서 네트워크 및 구조물 건강 모니터링 등 저전력 전자기기의 자가 공급 시스템 구현에 기여하고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
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
