• 한국소음진동공학회논문집
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• 제24권2호
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• pp.87-92
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• 2014

이 논문에서는 기존 외팔보 빔 형상을 가진 진동 에너지 하베스터의 작동 주파수 범위를 공진 주파수 이후로 확장하기 위해 새로운 형태의 진동 에너지 하베스터가 제시되었다. 압전 재료를 사용한 기존 외팔보 빔 형상의 진동 에너지 하베스터에 레버형 반공진 시스템에서 발생하는 극점-영점 상쇄 기법을 적용하여 작동 주파수 영역을 확장하였다. 간단한 이론적 해석 및 실험을 통해 제안된 광역 압전 진동 에너지 하베스터의 실현 가능성을 검증하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.819-824
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• 2012

This paper presents the wideband vibration system of an electromagnetic vibration energy harvester that obtained electric power for wireless sensor applications from the ever-change vibrations of bridge. It is a system with two degree of freedom vibrations that are composed of two mass and two spring respectively. One system is housing mass and spring, the other is the magnetic mass and spring that is the vibration system construction's element of electromagnetic vibration energy harvester. In other words, it is called dynamic vibration absorber. This paper show that the ratio of housing mass to magnetic mass decides the bandwidth and the size of amplitude of magnetic mass in electromagnetic vibration energy harvester. Therefore, it is necessary to improve the efficiency of energy in electromagnetic vibration energy harvester for wireless sensor applications.

• 한국생산제조학회지
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• 제24권6호
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• pp.619-624
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• 2015

Owing to miniaturization and low-power electronics, mobile, implanted, and wearable devices have become the main trends of electronics during the past decade. There has been much research regarding energy harvesting to achieve battery-free or self-powered devices. The optimal design problems of a double-pendulum kinetic-energy harvester from human motion are studied in this paper. For the given form factor, the weight of the harvester, and the known human excitation, the optimal design problem is solved using a dynamic non-linear double-pendulum model and an electric generator. The average electrical power was selected as the performance index for the given time period. A double-pendulum harvester was proven to be more efficient than a single-pendulum harvester when the appropriate parameters were used.

• 센서학회지
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• 제21권3호
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• pp.172-179
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• 2012

This paper presents the design and analysis of a vibration-driven electromagnetic energy harvester that uses a multi-pole magnet. The physical backgrounds of the vibration electromagnetic energy harvester are reported, and an ANSYS finite element analysis simulation has been used to determine the different alignments of the magnetic pole array with their flux lines and density. The basic working principles for a single and multi-pole magnet are illustrated and the proposed harvester has been presented in a schematic diagram. Mechanical parameters such as input frequency, maximum displacement, number of coil turns, and load resistance have been analyzed to obtain an optimized output power for the harvester through theoretical study. The paper reports a maximum of 1.005 mW of power with a load resistance of $1.9k{\Omega}$ for 5 magnets with 450 coil turns.

• Journal of Biosystems Engineering
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• 제40권2호
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• pp.102-109
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• 2015

Purpose: Slow manual harvesting of rain-fed chickpeas cultivated in fallow fields in developing countries have encouraged the design of a mechanical harvester. Methods: A tractor-pulled harvester was built, in which a modified stripper header detached pods from an anchored plant and a chain conveyor transferred material. The stripper harvester was redesigned to use: 1) the maneuverability of tractor-mounted frames, 2) the adaptability of floating headers, and 3) the flexibility of pneumatic conveyors. Results: A mobile vacuum conveyor, which was an innovator open system, was designed for the dilute phase transferring mode for both grain and material other than grain. A centrifugal fan transferred harvested material to a cyclone separator that settled harvested material in a grain tank 1 m high. The machine at the spot work rate of $0.42ha{\cdot}h^{-1}$ harvested chickpea pods equal to the output of 16.6 farm laborers. Conclusion: The low cost and reasonable projected purchase price are the advantages of the concept. Additionally, the shattering loss reduction confirms the feasibility of the prototype chickpea harvester for commercialization.

• 농업과학연구
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• 제44권1호
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• pp.114-122
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• 2017

An experimental pick-up type pulse crop harvester was built and its harvesting performance for green kernel black bean was evaluated. Field bean loss and harvested bean quality of the harvester were analyzed according to engine speeds of 2,000; 2,400; 2,800; 3,000; and 3,200 rpm, and travel speeds of 0.6; 1.0; and 1.4 m/s. Operating conditions and field capacity of the harvester for proper harvesting were estimated. The harvester had an optimum performance at a grain moisture content of 13.4%, an engine speed of 3,000 rpm, and a travel speed of 1.2 - 1.3 m/s. Subsequently, the picking-up, discharging, and total bean loss ratios were found to be 1.6, 1.3, and 2.9%, respectively. The whole bean, damaged bean, unthreshed bean, and foreign material ratios were determined to be 96.2, 1.0, 0.1, and 0.3%, respectively. Results showed that the harvester had lower bean loss and higher harvested bean quality than those of imported bean combines. The harvester could harvest 2 rows with a crop spacing of an approximately 1.4 m. Its optimum travel speed was estimated to be approximately 1.2 m/s when harvesting performance was taken into account using such variables as field bean loss and harvested bean quality for green kernel black bean. Effective field capacity of the harvester was estimated at approximately 40 a/h.

• 드라이브 ㆍ 컨트롤
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• 제21권1호
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• pp.38-45
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• 2024

The power delivery is crucial to designing agricultural machinery. Therefore, the tractor-mounted potato harvester was used in this study to conduct the field experiment and analyze the power delivery for each step. This study was focused on an analysis of power delivery from the engine to the hydraulic components for the tractor-mounted harvester during potato harvesting. Finally, the simulation model of a self-propelled potato harvester was developed and validated using the experimental dataset of the tractor-mounted potato harvester. The power delivery analysis showed that approximately 90.22% of the engine power was used as traction power to drive the tractor-mounted harvester, and only 5.10% of the engine power was used for the entire hydraulic system of the tractor and operated the harvester. The statistical analysis of the simulation and experimental results showed that the coefficient of determinations (R²) ranged from 0.80 to 0.96, which indicates that the simulation model was performed with an accuracy of over 80%. The regression models were correlated linearly with the simulation and experimental results. Therefore, we believe that this study could contribute to the design methodology and performance test procedure of agricultural machinery. This basic study would be helpful in the design of a self-propelled potato harvester.

• 지역연구
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• 제33권3호
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• pp.49-59
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• 2017

본 연구에서는 경부고속도로 일부구간(신갈JC~수원신갈IC)에 압전에너지 하베스터를 설치한 후 수확된 전력으로 주거지의 가로등 전력을 대체하는 정책에 대한 비용편익분석을 실시하였다. 이때 비시장재효과인 하베스터 설치에 따른 주민의 사회적 편익은 구체적으로 지역 주민의 삶의 질 향상 효과, Blackout 대비효과 등을 포함하며 조건부가치측정법을 사용하여 추정하였다. 분석 결과 압전 에너지하베스팅 기술의 고속도로 적용은 사회적 편익효과를 고려하였을 때 경제성이 있는 것으로 나타났다.

• 한국기계가공학회지
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• 제17권2호
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• pp.1-7
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• 2018

Recently, as interest in the internet of things has increased, a vibration energy harvester has attracted attention as a power supply method for a wireless sensor. The vibration energy harvester can be divided into piezoelectric types, electromagnetic type and electrostatic type, according to the energy conversion type. The electromagnetic vibration energy harvester has advantages, in terms of output density and design flexibility, compared to other methods. The efficiency of an electromagnetic vibration energy harvester is determined by the shape, size, and spacing of coils and magnets. Generating all the experimental cases is expensive, in terms of time and money. This study proposes a method to perform design optimization of an electromagnetic vibration energy harvester using an open source, big data platform.

• 센서학회지
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• 제28권1호
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• pp.36-40
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• 2019

Energy harvesting is an advantageous technology for wireless sensor networks (WSNs) that dispenses with the need for periodic replacement of batteries. WSNs are composed of numerous sensors for the collection of data and communication; hence, they are important in the Internet of Things (IoT). However, due to low power generation and energy conversion efficiency, harvesting technologies have so far been utilized in limited applications. In this study, a piezoelectric energy harvester was modeled in a vibration environment. This harvester has an oval-shaped configuration as compared to the conventional cantilever-type piezoelectric energy harvester. An analytical model based on an equivalent circuit was developed to appraise the advantages of the oval-shaped piezoelectric energy harvester in which several structural parameters were optimized for higher output performance in given vibration environments. As a result, an oval-shaped energy harvester with an average output power of 2.58 mW at 0.5 g and 60 Hz vibration conditions was developed. These technical approaches provided an opportunity to appreciate the significance of autonomous sensor networks.