• 설비공학논문집
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• 제8권3호
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• pp.317-329
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• 1996

By describing the floor slab of a radiant heating system as a one dimensional transient heat exchanger problem, a dynamic analysis model to incorperate with TRNSYS program was developed and their results were compared with experimental results. Results showed that the both of TPOC(Two Parameter On-off Control) and TPSC(Two Parameter Switching Control) method using room air temperature and floor surface temperature as the control parameters does not maintain room air and floor surface temperature exactly at the setting temperatures. But TPSC method is a better candidate for the temperature regulations of room air and floor surface temperature than TPOC method which can keep on the upper and lower limit temperature according to outside temeperature and wall structure etc. And better thermal circumstance can be given by TPSC method than On-off and TPOC method and the overheating which can be occured at the radiant floor heating system with on-off heating control will be reduced.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.369-378
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• 1999

This paper presents position control of an electro-hydraulic servo system whoch is operated by four 2-2way high speed on-off valves with either PWM PID control method or sliding mode control method, The advantages of using high speed on-off valves instead of electo-hydraulic servo valves or electro-hydraulic proportional valves are low price robustness for oil contamination and direct control without a D/A converter. The system consists of load cylinder inertia car potentiometer and external load cylinder. The experiments were carried out under several conditions and the results were compared. As a result the sliding mode method has shown good control performance and the robust and stable positioning of the elector-hydraulic servo system can be achieved accurately.

• 조명전기설비학회논문지
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• 제18권6호
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• pp.78-83
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• 2004

현재 운용되고 있는 직접부하제어 알고리즘은 직접부하제어 사업에 참여에 따른 수용가의 개별 부하별 우선순위가 고려되지 않고 있고, 또한 제어 시간도 수용가의 불편을 고려되지 않고 획일적으로 일정 시간대에 일률적으로 수용가의 부하를 제어함으로써 참여 수용가의 불편 증대로 참여율이 저조한 실정이다. 따라서 본 연구에서는 참여 수용가의 불편을 최소화시키고 또한 개별 부하에 대한 우선순위 요구를 최대한으로 반영하기 위해 우선순위 기반 동적 프로그래밍을 이용한 직접부하제어 알고리즘을 제시한다. 제시되는 알고리즘은 직접부하제어가 발생되기 1시간 전에 참여 수용가가 스스로 해당 부하의 우선순위를 결정하여 직접부하제어 센터로 I-Mail 등으로 보네면 센터에서는 현재 부하의 전력량과 우선순위 그리고 OFF주기 등을 고려하여 동적 프로그래밍을 수행하여 OFF되어야 할 부하들을 선택하게 된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.28-31
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• 1997

This paper describes the quick and precise controlling method for home-applied refrigerator. The proposed controller is based on the fuzzy logic control method and is designed for better performance in maintaining the constant temperature of the refrigerator. The temperature of the refrigerator is controlled by the cooling air blowing fan motor which is put on, off according to fuzzy logic controller. Finally, I study the performance of the proposed controller through the computer simulation about the approximated model of the refrigerator.

• 한국정밀공학회지
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• 제20권8호
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• pp.86-93
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• 2003

The development of a fast, accurate, and inexpensive position-controlled pneumatic actuator that may be applied to a variety of practical positioning applications with various external loads is described in this paper. A novel modified pulse width modulation (MPWM) valve pulsing algorithm allows on/off solenoid valves to be used in place of costly servo valves. A comparison between the system response of standard PWM technique and that of the novel modified PWM technique shows that the control performance is significantly increased. A state feedback controller with position, velocity and acceleration feedback is successfully implemented as the continuous controller. Switching algorithm of control parameter using learning vector quantization neural network (LVQNN) is newly proposed, which estimates the external loads of the pneumatic actuator. The effectiveness of the proposed control algorithms are demonstrated through experiments with various loads.

• 제어로봇시스템학회논문지
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• 제11권2호
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• pp.103-108
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• 2005

Loading/Unloading task in the real industry is performed by crane, but most of the loading/unloading task with the weight of 5kg∼30kg is done by human workers and this kind of work causes industrial disaster of workers. Therefore it is necessary to develop low cost loading/unloading manipulator system to prevent this kind of industrial accidents. This paper is concerned with the design and fabrication of 2 axis pneumatic manipulators using on/off solenoid valves and accurate position control without respect to the external load and low damping in the pneumatic rotary actuator. To overcome the change of external load, switching of control parameter using LVQNN (Learning Vector Quantization Neural Network) is newly applied, which estimates the external loads in the pneumatic cylinder. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied to the switching control system. The effectiveness of the proposed control algorithms are demonstrated through experiments of pneumatic cylinder with various loads.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1322-1325
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• 1997

A new feedback control law design techniqed usign of-off thrusters for the rotational maneuver of a flexible arm is discussed in this study. a two state on-off thruster actuator is taken as a primary actuation device for theis study. The on-off thruster operation is emulated in conjunction with the conventioal minimum-time trackig control law. The actuator input region is divided into two separate parts ; one is constant input and the other is time varying tegion. the new control law has potential applicatioin for the relatively low frequency structure such as large flexible space structure being currently used in various space echnology areas.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.46.4-46
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• 2001

This paper presents a Five-Switch Converter (FSC) circuit that can operate like a full-bridge PWM converter for driving the DC motor in bidirectional. One of the main advantages of this circuit is to reduce the on-off switching number of power MOSFET. In stead of turning on-off simultaneously two of the four power MOSFET´s in a switching period, this circuit operates only one power MOSFET, while continuously leaving another two on and the other two off in the switching period. Consequently ...

• 설비공학논문집
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• 제13권11호
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• pp.1165-1173
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• 2001

The objectives of this study are to analyze the application of radiant floor cooling and to evaluate the control methods through experiments when the radiant heating system is used for cooling. Through the experiment analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The cooling curve (reset ratio) is found for radiant cooling, which shows tole relation between outside air temperature and supply water temperature. Comparison of cooling methods shows that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• 전력전자학회논문지
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• 제12권6호
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• pp.510-516
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• 2007

본 논문에서는 더 높은 에너지 효율을 요구하는 전자 기기들의 사용에 따른 고전력 밀도 AC/DC adapter를 위한 향상된 제어 방법을 제안한다. PFC (Power Factor Correction) 토폴로지는 BCM (Boundary Conduction Mode)제어 방식을 적용한 부스트 토폴로지를 기본으로 하였으며, DC/DC 토폴로지는 50% 고정 duty법과 함께 새롭게 제안된 Off-time 제어법을 적용한 하프브릿지 토폴로지를 기본으로 하였다. 이는 반도체 소자와 마그네틱 소자의 크기를 줄이는데 용이하다. 85W급 AC/DC 어뎁터(18.5V/4.6A)를 설계하여 실험한 결과 90%의 효율과 $36W/in^3$의 전력밀도가 측정되었고 무부하시 전력 손실은 0.5W를 달성하였다.