• 공학교육연구
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• 제20권4호
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• pp.61-66
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• 2017

Automatic flow control system composed by hardware and software was designed and fabricated to be used as teaching tool of feedback control theory in university experimental class. This system includes hardwares like data acquisition board, flow measuring device, transmitters, and the pneumatic valve, and software like LabView program for the monitoring and control of flow rates. The system was designed as the student can see the control effect of not only set point but also disturbance changes. Also the LabView program was composed for the calculation of controller parameters of both Ziegler-Nichols and Cohen-Coon tuning. The students can apply both tuning constants and compare the control performances. This system will provide the easy way for the students to understand the function and specification of control hardwares, and to raise the programing ability of control software.

• 한국정밀공학회지
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• 제14권12호
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• pp.95-104
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• 1997

We consider controller design problem to enhance shift quality for automatic transmission. A dynamic modeling related to shifting (mainly 2-3 up-shift) is constructed and nonlinear robust controllers are designed to reduce output torque during shifting. Suggesting a new hydraulic circuit enabling the direct clutch drive, the control activity is extended and more implementable than the conventional design. The designed robust controllers overcome the unmodeled dynamics and the uncertainty embending in the system. Moreover, the dynamic effect between the clutch pressure and the PWM valve duty is considered via singular perturbation technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.715-717
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• 1999

In this study, an intelligent solenoid valve controller has been developed for automatic maintaining of filters in a dust collecting system. This controller has automatic controllability of solenoid valves' ON/OFF time depending on the clogging status of filters, and then it can extend the filters' lifetimes, decrease the power consumption, and make effective operation of the system possible. This controllability has been executed by the fuzzy theory that utilizes the workers' experimental knowledges, the control expert's knowledges and the differential pressures between the inlets and outlets measured by the sensors.

• 한국정밀공학회지
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• 제18권9호
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• pp.53-60
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• 2001

This paper presents a position control of a platform at the seaport cargo handling system. After brief description of the operating principles of the cargo handling system, the governing equation of the moving platform is derived. The equation is described in the state space model, and a robust H$_{\infty}$ controller to achieve position tracking of the moving platform. which can carry 200ton of containers, is formulated. In the synthesis of the controller, the weight of the container is treated as uncertain parameter. Both regulating and tracking control responses are analyzed for the loading and unloading procedures of the proposed automatic cargo handling system.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.457-462
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• 2005

In this study, the performance of automatic thermostatic valves according to each heating method of a large scale residential building were researched by simulation. The flow characteristics of the entire pipe networks of the hot water radiant heating system is analized by using linear analysis method. For the analysis of unsteady heat transfer phenomena in each household, the method of using electric equivalent R-C circuit is applied.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.381-386
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• 2008

In this study, the energy characteristic of automatic thermostatic valves according to each heating method in floor radiant heating system were researched by computer simulation. For the analysis of unsteady heat transfer phenomena in household, the method of using electrical equivalent R-C circuit is applied, and radiation heat transfer between panel, ceiling and walls in household is calculated by enclosure analysis method. The parametric study on heating method, valve's control method, outdoor air condition, supply heating water temperature, supply flow rate are performed to compare energy characteristic, respectively.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.52-57
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• 2007

The control characteristics for radiant panel heating system with automatic thermostatic valves were researched by computer simulation and experiment. The unsteady energy analysis using equivalent R-C circuit method and radiation heat transfer analysis of enclosure analysis method with simple structured rooms was performed. The results of flow rate changes of the simulation study are good fit with the ones of experimental one.

• 드라이브 ㆍ 컨트롤
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• 제18권2호
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• pp.46-55
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• 2021

A forklift is a powered industrial vehicle used to lift and move materials over short distances. Nowadays, almost all forklifts are equipped with an automatic transmission due to its improved operator comfort and increased productivity. Thanks to marked improvement of transmission control unit equipped with highly-advanced microcontrollers, recently developed automatic transmission for forklift have various auxiliary functions such as creep, auto retardation, and automatic shift with excellent shift quality. This paper deals with the creep function which enables one to maneuver a forklift at the designated low speed by slip control of clutches. The design of creep function was based on four modes of creep operation depending on the status of the operator's shift lever and accelerator pedal. Control algorithms and control parameters for each mode were designed to achieve the desired static and dynamic performance. Vehicle test for the designed creep function was carried out with an independently developed embedded controller. Test results confirmed good creep speed control without speed error at a steady state with a mild shift shock during mode changes by stepping or releasing the accelerator.

• KSBB Journal
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• 제15권4호
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• pp.388-392
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• 2000

한지자숙폐액을 이용한 Saccharomyces cerevisiae의 배양에 서 glucose의 자동분석 및 첨가에 의해 균농도를 증가시킴으로써 폐액의 재이용성을 향상시키파 하였다 배양액의 glucose를 자동분석하고 자동첨가하기 위하여 ceramic sampler, sampling, ralve, injection valve, glucose oxidase column, debubbler, flow cell과 백금전극, potentiostat, computer와 interface card, 및 tubing pump블로 구성된 glucose 자동분석 및 첨가시스템을 제작하였으며, glucose의 자동분석에는 glucose oxidase를 이용한 on-line FIA법을 채택하였다. 효모의 배양중 glucose자 동분석 및 첨가시스템을 사용하여 glucose를 자동첨가한 결과 배양액의 포도당농도가 $176{\pm}31 mg/L$ 의 낮은 농도로 제어 되었으며, glucose와 $>(NH_4)_2S0_4$의 첨가에 의해 총균수가 3.1 배 증가하였다.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.773-779
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• 2021

CNG, which has recently been attracting attention as an alternative fuel in the transportation field to reduce emissions caused by global warming, is natural gas with abundant reserves and mainly composed of methane. Being in a gaseous state, natural gas requires the compression and liquefaction processes for transportation. Until now, general shut-off valves for liquid and gas piping have been developed in Korea, but there are few studies on shut-off valves for high pressures of about 200 bar. Currently, research on the flow analysis of valves is being actively conducted around the world. However, there are relatively many studies on large valves such as low-pressure valves or shipbuilding and marine, and the safety factor through structural analysis to check the structural integrity of the valve is checked at the design stage. Since it is necessary to have a fast response speed while minimizing pressure and speed loss due to flow change, basic research was conducted on the flow analysis of the valve to secure design data, and the numerical analysis was performed on high-pressure automatic shut-off valves applied to CNG refueling stations. After securing the basic valve shape through reverse engineering for advanced products, we compared the valve flow coefficient Cv coefficient with advanced products. As a result, it was found that the reverse engineering model was at the level of about 60%. However, we compared the Cv coefficient by modifying the reverse engineering model, and the result showed that it was improved to about 96%.