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Seongil Kim,최상민,Jongin Yang 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12
A case of dynamic performance simulation model of a CFB boiler is presented in this study. The dynamic system of a CFB boiler in an operating power plant and the transient behavior of sub-models is described in the accompanying paper, Part I. The current paper, Part II, describes the model extension for the CFB boiler system in a power plant. The open loop model in Paper I was expanded by applying a set of PID (Proportional-integral-differential) control loops. In the control loop, pressure, temperature, mass flow rate of the main steam, the drum water level and the oxygen level at the stack were controlled. Dynamic performance was simulated to check the response of the closed control loop. Finally, performance of the total boiler system for a range of operation load of the power plant was simulated, where the parameters were calculated and control variables were maintained at the set values by PID control. Dynamic performance of a boiler at a selected load variation case was simulated and compared with actual measurements and their transient response characteristics were discussed. The simulation can also directly produce useful operation parameters, which are not measurable, but could be used for engineering evaluation.
Seongil Yu(유성일),Jae-Chul Lee(이재철),Seungjae Ahn(안승재),Ki-Young Kim(김기영) 한국고분자학회 2020 폴리머 Vol.44 No.5
석유화학물질을 사용하는 것에서 벗어나기 위하여 바이오 기반의 원료를 사용하는 것에 대한 관심이 높아지고 있다. 식물자원으로부터 생산되는 바이오 기반의 원료는 친환경적이며 지속 가능한 자원으로 여겨진다. 현재 널리 사용되고 있는 poly(ethylene terephthalate)(PET)의 대체 후보로 poly(ethylene 2,5-furandicarboxylate)(PEF)가 기대되고 있다. 본 연구는, 플라스크와 kneader 반응기에서 PEF를 중합하여 특성을 비교, 확인하였다. Kneader 반응기에서 효과적으로 PEF를 합성할 수 있었으며, 결과물을 용융 방사한 섬유는 1.80 g/den의 인장강도와, 114.25%의 변형률을 보여주어 PEF를 섬유로 사용할 수 있는 가능성을 확인하였다. There is a growing interest in using bio-based raw materials as a replacement for petrochemical materials. Biobased materials produced from plant resources are considered environmentally sustainable resources. Poly(ethylene 2,5-furandicarboxylate) (PEF) is now widely used and is considered the main substitute for poly(ethylene terephthalate) (PET). In this study, PEF was polymerized in a flask and a kneader reactor, and the properties of PEF were characterized. In the kneader reactor, PEF was synthesized effectively, and the resultant melt-spun fibers with a tensile strength of 1.80 g/den and a strain of 114.25% were obtained, confirming the possibility of utilizing PEF as a fiber.
Seongil Hong,Gyuhyun Park,Wonsuk Lee,Sincheon Kang 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10
We focus on the realization of the hierarchical inverse kinematics as a practical means of a hard real-time motion planning for a humanoid robot. To achieve complex on-line full body manipulation performance, a task priority is established among the tasks to precisely resolve task conflicts and all algorithms are described in recursive equations so as to minimize computation time. Formulating the kinematic problem in a least-square optimization enables us to derive solutions in a unified and consistent framework. The performance is validated through numerical simulations with bearing mind of rescue robot applications and finally, the inverse kinematic solution is found within 0:3msec on average for 19 degrees of freedom control.
Seongil Hwang(황성일),Hyunah Kang(강현아),Sang Hoon Kang(강상훈) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
The mechanical impedance of the human arm is a physical entity that corresponds to the clinical assessment of muscle tone, a muscle’s resistance to passive stretching. Quantification of the human arm mechanical impedance may provide us with a deeper understanding of the changes in upper limb post-stroke. A previous study using a low friction robot (i.e., MIT-MANUS) showed low reliability(< 0.8) of the estimation for frequency below ~5Hz. However, recent studies elucidated that the low reliability could be due to nonlinearities in the robot (e.g., joint friction), not in the human arm. In this study, to clarify the reason for the low reliability, the experiment was conducted using a direct-drive robot almost identical to the MIT-MANUS, and the spring arrays, the second-order linear system. The result showed high reliability under a robust impedance control compensating nonlinearity of robots, but low reliability under a simple PD control. This is indirect yet strong evidence that the low reliability was caused by the nonlinearity of the robots, not the human arm.
Kinematic Control Algorithms and Robust Controller Design for Rescue Robot
Seongil Hong,Won Suk Lee,Youn Sik Kang,Yong Woon Park 제어로봇시스템학회 2014 제어로봇시스템학회 국제학술대회 논문집 Vol.2014 No.10
This paper introduces the Korean rescue robot and presents the kinematic and dynamic control method. The mission of the rescue robot is to move and lift patients or soldiers with impaired mobility for the rescue and assistance in the battlefields, hospitals, hazardous and disastrous environments. In order for robots to rescue and assist humans in various environments, reliable mobility and dextrous manipulability are required. For these objects the robot has variable configuration mobile platform with tracks, dual arm manipulators and two types of grippers. The electric actuators provide manipulator compliance and the strength to lift wounded soldiers up to 120kg by virtue of whole body joints. For controlling the robot’s high degree of freedom efficiently, complex whole body behaviors are synthesized and multi level hierarchy is used to integrate multiple task primitives without confliction. Moreover, the robot should have an ability to cope with large payload variation from 0kg to 120kg, robust PID controllers are utilized. They afford extended disturbance input to state stability, H∞ performance and controller tuning laws. We are to demonstrate the effectiveness of kinematic control algorithms and robust PID controllers through numerical simulations.
A Numerical Analysis on Separating Performance for Oil Separator
Seongil Jang,Joon Ahn 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.10
A series of numerical simulation has been carried out to study performance of a cyclone type oil separator, which is designed for the compressor of a refrigeration system. Working fluid is R22, which is a typical refrigerant, and mineral oil droplet is supplied. Pitch of the helix is considered as design parameters to make a compact separator. Depending on the helix pitch, separation efficiency varies from 97.5 to 99%, while predicted pressure drop ranges from 5 to 6.5 kPa. Considering both of the pressure drop and separation efficiency, helix pitch of the separator has been designed as 50 mm.