Analysis on Torque, Flowrate, and Volumetric Displacement of Gerotor Pump/Motor

Yun, Hongsik,Ham, Young-Bog,Kim, Sungdong The Korean Society for Fluid Power and Constructio 2020 드라이브·컨트롤 Vol.17 No.2

It is difficult to analytically derive the relationship among volumetric displacement, flowrate, torque, and rotation speed regarding an instantaneous position of gerotor hydraulic pumps/motors. This can be explained by the geometric shape of the rotors, which is highly complicated. Herein, an analytical method for the instantaneous torque, rotation speed, flowrate, and volumetric displacement of a pump/motor is proposed. The method is based on two physical concepts: energy conservation and torque equilibrium. The instantaneous torque of a pump/motor shaft is determined for the posture of rotors from the torque equilibrium. If the torque equilibrium is combined with the energy conservation between the hydraulic energy of the pump/motor and the mechanical input/output energy, the formula for determining the instantaneous volumetric displacement and flowrate is derived. The numerical values of the instantaneous volumetric displacement, torque, rotation speed, and flowrate are calculated via the MATLAB software programs, and they are illustrated for the case in which inner and outer rotors rotate with respect to fixed axes. The degrees of torque fluctuation, speed fluctuation, and flowrate fluctuation can be observed from their instantaneous values. The proposed formula may provide a better understanding of the design or analysis process of gerotor pumps/motors.

Analysis on Torque, Flowrate, and Volumetric Displacement of Gerotor Pump/Motor

Hongsik Yun,Young-Bog Ham,Sungdong Kim 유공압건설기계학회 2020 드라이브·컨트롤 Vol.17 No.2

It is difficult to analytically derive the relationship among volumetric displacement, flowrate, torque, and rotation speed regarding an instantaneous position of gerotor hydraulic pumps/motors. This can be explained by the geometric shape of the rotors, which is highly complicated. Herein, an analytical method for the instantaneous torque, rotation speed, flowrate, and volumetric displacement of a pump/motor is proposed. The method is based on two physical concepts: energy conservation and torque equilibrium. The instantaneous torque of a pump/motor shaft is determined for the posture of rotors from the torque equilibrium. If the torque equilibrium is combined with the energy conservation between the hydraulic energy of the pump/motor and the mechanical input/output energy, the formula for determining the instantaneous volumetric displacement and flowrate is derived. The numerical values of the instantaneous volumetric displacement, torque, rotation speed, and flowrate are calculated via the MATLAB software programs, and they are illustrated for the case in which inner and outer rotors rotate with respect to fixed axes. The degrees of torque fluctuation, speed fluctuation, and flowrate fluctuation can be observed from their instantaneous values. The proposed formula may provide a better understanding of the design or analysis process of gerotor pumps/motors.

서보밸브-미터링 실린더 시스템의 오일 관성효과와 주파수 응답 특성에 관한 연구

윤홍식(Hongsik Yun),김성동(SungDong Kim) 유공압건설기계학회 2021 드라이브·컨트롤 Vol.18 No.2

The spool displacement signal of a directional control valve, including the servo valve, can be considered as the standard signal to measure dynamic characteristics. When the spool displacement signal is not available, the velocity signal of a metering cylinder piston can be used. In this study, the frequency response characteristics of the metering cylinder are investigated for the spool displacement input. The transfer functions of the servo valve-metering system are derived taking into consideration the oil inertia effect in the transmission lines. The theoretical results of the transfer functions are verified through computer simulations and experiments. The oil inertia effect in the transmission lines was found to have a very significant effect on the bandwidth frequency of the servo valve-metering cylinder system. In order to more precisely measure the dynamic characteristics of a servo valve, the metering cylinder should be set up to minimize the oil inertia effect by increasing the inner diameters of the transmission lines or shortening their lengths.

서보밸브의 주파수 응답 신호에 관한 연구

윤홍식(Hongsik Yun),김성동(SungDong Kim) 유공압건설기계학회 2021 드라이브·컨트롤 Vol.18 No.1

The flow signal or spool position signal is used to determine the dynamic characteristics of directional control valves. Alternatively, the signal of spool position or flow can be replaced with the velocity of a low friction, low inertia actuator. In this study, the frequency response of the servo valve equipped with a spool position transducer is measured with a metering cylinder. The input signal, spool displacement, load pressure, and velocity of the metering cylinder are measured, and the theoretical results from the transfer function analysis are verified. The superposition rule for magnitude ratio and phase angle was found to be always applicable among any signal type, and it was found that the load pressure signal is not appropriate for use as the signal for measuring the frequency response of a servo valve. It was confirmed that the frequency response of a servo valve using metering cylinder was similar to the results from a spool displacement signal. The metering cylinder used for measuring the frequency response of a servo valve should be designed to have sufficiently greater bandwidth frequency than the bandwidth frequency of the servo valve.

텅스텐을 이용한 의료용 X-선 차폐시트 제조와 조성 최적화

윤재한(Jaehan Yun),후건(Jian Hou),장원기(Wongi Jang),김준현(Jun-Hyun Kim),변홍식(Hongsik Byun) 한국고분자학회 2019 폴리머 Vol.43 No.3

본 연구에서는 방사선 차폐물질로 사용되는 납을 대체하기 위하여, 무기금속 물질 중 원자번호가 큰 분말 상태의 텅스텐을 사용하였으며, 폴리우레탄(polyurethane, PU)과 복합하여 차폐용 시트를 제조하고 최적화를 진행하였다. 차폐시트의 구성은 고분자대비 1:1, 1:5, 1:10 비율로 텅스텐 함량을 증가시켜 제조하였으며, 광학이미지와 SEM으로 단면촬영을 진행하여 구조를 확인하였다. 또 질량감쇠계수와 차폐율의 변화를 확인하였다. 무기물의 함량이 증가할수록 시트의 밀도가 증가하였으며, 차폐율 또한 증가하는 것을 확인하였다. 열처리를 통해 차폐시트에 포함되어 있는 텅스텐의 양을 확인하였으며, 함량과 질량감쇠계수를 비교하여 최적화된 비율을 찾았다. In this study, tungsten (W) powder, which is high atomic number element among inorganic maerials was considered as an alternative material for the lead (Pb) generally used as radiation shielding material. The shielding sheets were prepared by the complexation of tungsten powder and polyurethane (PU), and their optimization was carried out. The sheets were prepared by increasing the tungsten contents to the polymer where the composition was 1:1, 1:5, and 1:10 (polymer:tungsten). The morphology of sheet was investigated by using optical microscopy and scanning electron microscopy (SEM). The increases of both sheets density and their shielding efficiency were observed with increasing the contents of inorganic filler into composite. The weight of tungsten in the final shielding sheet was confirmed through a heat treatment and the optimized composition ratio was obtained by considering the total weight and mass attenuation coefficient of the sheet.

GOCI 영상, 적조 부이와 DTA를 이용한 유해성 적조 방제 체계

송문수(Moonsoo Song),윤홍식(Hongsik Yun) 대한공간정보학회 2016 한국지형공간정보학회 학술대회 Vol.2016 No.10

최근 해수 온도의 급격한 상승에 따라 기후변화가 일어나고 있으며 적조로 인한 직 · 간접적 피해가 매년 발생하고 있다. 적조현상은 부패성 유기 오염물질과 미량금속 및 증식촉진물질이 풍부하게 용존 되어 있고, 일사량, 수온, 염분 등 환경조건이 충족되어 유해성 조류가 대량번식하면 발생하며, 특히 바람이나 조류에 의하여 집적되면 고밀도 적조가 발생한다. 남해안과 같이 생활하수가 다량 유입되고 저층에 퇴적된 영양물질이 용출되는 곳에서 (계절에 관계없이 발생하는 원인이 된다.) 상습적으로 발생한다. 1995년에 발생한 코클로디니움에 의한 적조는 764억원의 기록적인 수산피해를 입히면서, 신속한 대응과 효과적인 방제작업의 필요성이 대두되었다. 본 논문에서는 남해안에서 발생한 적조를 천리안해양관측위성(GOCI, Geostationary Ocean Color Imager)영상을 이용한 Son et al.(2011)의 spectral classification 방법을 사용하여 적조인 경우와 아닌 경우로 분류하고, 적조부이에 구성된 센서들을 이용하여 적조를 유발하는 인자와 이동경로 등을 모니터링하는 네트워크를 구성하였다. 이를 통해 적조를 예찰 · 예보하고 의사결정나무(DTA, Decision Tree Analysis)를 통해, 각 예보수준에 따른 대응방향과 방제활동 단계까지의 과정에 대하여 제시하였다.

Development of Biodegradable Polymer Coating Urea for Mitigation of Agro-Environmental Impacts

DongKeon Lee(이동건),HongSik Na(나홍식),Oyen Kewon(권오연),WooJin Jeng(정우진),SeokIn Yun(윤석인),JoungDu Shin(신중두) 한국토양비료학회 2022 한국토양비료학회 학술발표회 초록집 Vol.2022 No.10

지방자치단체의 기능연속성계획 도입을 위한 정책 연구

신정훈(Shin Jeonghoon),윤홍식(Yun Hongsik),권정환(Kwon Jeonghwan),양소명(Yang Somyung) 한국방재학회 2018 한국방재학회논문집 Vol.18 No.2

In recent years, the Korean government has recognized the necessity of functional continuity of public institutions and has established 「Framework Act on the Management of Disaster and safety」 so that public institutions can build ‘Continuity of Operation Plan’. This study is based on theories and precedents, functional classification and determine recovery time objective for effective introduction of ‘Continuity of Operation Plan’ of local government. Based on business reference model (BRM), Look for a way that The functions of local governments are classified into daily function and emergency function from perspective of Continuity of Operation Plan. Based on the analysis and the logic of the case study, it was concluded that recovery time objective needs appropriate unity and that a flexible recovery time objective reflecting the characteristics of the function and the reality should be determined. 최근 국내에서 기능의 연속성에 대한 필요성 인식하여 공공기관에 대해 기능연속성계획을 구축하도록 「재난 및 안전관리기본법」에 신설하였다. 본 연구는 지방자치단체의 효과적인 기능연속성계획 도입을 위해 기능 분류와 복구목표기간에 대한 이론과 선행사례를 바탕으로 정책적인 고찰을 수행하였다. 기능 분류는 지방자치단체의 기능분류체계(BRM)에서 기능연속성 관점으로 일상기능과 비상기능으로 재분류하는 방안을 모색하였다. 복구목표기간에 대해서는 해외 사례조사를 통한 분석과 논리에 근거하여 적절한 통일성이 요구되며, 기능의 특성과 현실 가능성을 반영한 유동적인 복구목표기간이 결정되어야 한다는 결론을 도출하였다.

재난별 피해예측결과와 연계하기 위한 건축물 인벤토리 구축 방안에 대한 연구

정운철(Jung Woonchul),윤홍식(Yun Hongsik),정명훈(Jeong Myeonghun),권정환(Kwon Jeonghwan) 한국방재학회 2018 한국방재학회논문집 Vol.18 No.3

본 연구는 대형재난을 대비해 모델링된 자연재난 13종과 사회재난 8종의 피해예측결과들과 연계하기위한 건축물 인벤토리를 실험적으로 구축하고, 해당건축물에 재난별 대비사항을 도출하는 방안을 검토하였다. 최근 전국적으로 발생하는 대형재난에 대비하여 전국 1 km×1 km 격자의 자연재난 13종과 사회재난 8종을 모델링한 피해예측결과에 대해 연계방안을 검토하였다. 건축물 인벤토리 구축을 위해 전국단위 분석이 가능하고 공공의 목적으로 구축된 시스템의 데이터베이스 중 재난별 대비사항을 도출할 수 있는 속성정보를 관리하고 있는 한국시설안전공단의 시설물정보관리시스템(FMS: Facility Management System)을 활용하였다. 시설물정보관리시스템에 적합하게 구축된 데이터베이스 속성정보 및 형식을 피해예측결과들과 효율적으로 연계하기 위해 건축물 인벤토리의 적합한 구축방안을 검토하였다. This study aims to develop a building inventory to link the damage prediction results of major disaster models including 13 types of natural disasters and 8 types of social disasters. In order to cope with the recent large-scale disasters occurring nationwide, this research used the damage prediction results which are based on a 1 km×1 km grid across the country. The facility information management system in Korea Facility Safety Corporation also was utilized to develop the building inventory. The facility information management system holds a number of property information that can be used to derive the disaster preparedness information, which results in the nationwide analysis. This paper proposes the proper construction method of the building inventory in order to effectively link the attribute information of the facility information management system to the damage prediction results.

The Introduction of building a Cylindrical Multi Display System by Game Engine

Hyungjin Jeon,Eeljin Chae,Hongsik Pak,Taesoo Yun 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.7