• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2309-2312
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• 2003

This paper presents the minimization of the energy costs based on energy saving for industrial retort process of canned food. The approved proposed method is related the optimal steam or hot water flow control to achieve desired temperature of retort process. The smooth response and zero steady state error can be also achieved. The performances of the proposed control technique were observed using a small tuna canned food plant in Thailand as an illustrative example. The experimental results are given to support the saving in energy costs and some benefits of the proposed technique.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1062-1070
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• 1995

The study deals with controlling the velocity of hydraulic motor with PI controller through the control of displacement pump which has higher efficiency than valve-controlled system. This was done as follows. First, we modified original displacement pump and designed this electrohydraulic puma system. Second, after experimenting static and dynamic characteristics, we identified system parameter of approximated model. Lastly, to control the velocity of hydraulic motor we controlled the angle of the swash plate of displacement pump. Test carried out in the laboratory shows that transient and steady state response could be improved by PI controller reducing power loss.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.690-692
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• 2004

Differently from an existing analog control, because the digital control includes microprocessor basically, the digital control is enable to monitor internal parameters of DC-DC converter and to control output voltage remotely by communicating with a Windows based PC and also to monitor whether exact voltage is output or not. These things are impossible in an analog control. In this paper, a simple flyback converter is taken as a control target and is controlled by a microcontroller(TMS320F2812). This converter can make variable outputs 1.8V to 5V from 30V input voltage remotely in PC. Finally the response characteristics of a step reference voltage and in a steady state are experimented to verify the feasibility and the usefulness of this digital controlled converter.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.2
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• pp.23-28
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• 1983

In this paper, a method to control the speed of a dc motor using a phase locked loop circuit with a variable sequential filter is discussed. We improved the transient response time more than 15 percent compared to conventional system using a variable sequential filter and the steady state error was reduced to less than 0.05 percent per rotation axis.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.6
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• pp.562-566
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• 1991

Many research and development activities have found that Superconducting Generators (SCG) have advantages such as high efficiency, light weight, small size, large unit size and good steady-state stability over conventional ones. However the transient stability of SCG is comparable to that of conventional ones. One way to improve the transient stability of SCG is to apply quick-response excitation system to the SCG. For this purpose, an SCG with an electrothermal shield of short electric time constants should be developed. In this paper, a new electrothermal shield, called slitted electrothermal shield(SES), is proposed. The SES can easily transmit radiated heat into the ends of the shield as in the conventional electrothermal shields(CES) and can easily pass magnetic flux produced by armature and field windings. By finite element analysis and experimental test, the slitting effects of SES on magnetic shielding are compared. Good agreement is obtained between simulated and test results.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.184-188
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• 2001

In this paper, a new fully digital control method for single-phase UPS inverter, which is based on the double control loop such as the outer voltage control loop and inner current control loop, is proposed. The inner current control loop is designed and implemented in the form of internal model control and takes the presence of computational time-delay into account. Therefore, this method provides an overshoot-free reference-to-output response. In the proposed scheme, the outer voltage control loop employing P controller with resonance model implemented by a DSP is introduced. The proposed resonance model has an infinite gain at resonant frequency, and it exhibits a function similar to an integrator for AC component. Thus the outer voltage control loop causes no steady state error as regard to both magnitude and phase. The effectiveness of the proposed control system has been demonstrated by the simulation and experimental results respectively.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1178-1183
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• 2004

Temperature distribution and heating characteristic of the panel heater for infrared heating have been investigated. The temperature variation with time is firstly measured with the thermocouple to figure out the response time of the heater to the power input. The heater reaches faster to the steady state in comparison to the ceramic heater. The infrared thermal imaging system is utilized to investigate the temperature distribution over the heater surface. The measured thermal images show that the thermal boundary layer induced by the free convection near the heater surface affects the temperature distribution on the surface. The images also show the fairly good uniformity of the temperature distribution in the core region of the surface.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.109-118
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• 1995

This paper presents a mathematical vehicle model to analyze the dynamic characteristics of a vehicle undergoing braking in a turn. Two kinds of field tests, braking in a steady state turn and braking in a J-turn are performed. Computer simulation results are compared with test results and the braking effect on a vehicle cornering behavior is examined. Also, sensitivity analysis is applied to determine the effect of design parameter changes on the response of vehicle dynamic system.

• Journal of KSNVE
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• v.10 no.2
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• pp.325-330
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• 2000

A dynamic absorber is used to protect the primary vibration system under the steady-state harmonic disturbance. In a number of cases it appears expedient to install several absorbers of smaller masses instead of one. This may be due to the need of distribute the absorber's response along the construction, restrictions on the absorber's installation. So, we studied characteristics of the primary vibration system for the optimal natural frequency ratio and the optimal damping ratio of serial multi-dynamic absorber. Also we obtained the optimum values of the serial multi-dynamic absorber parameters using computer simulation for the damped primary vibration system. In designing multi-dynamic absorber, we presented for the optimal natural frequency and the optimal damping ratio of multi-dynamic absorbers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1375-1381
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• 2007

In this paper, we propose a linear modeling and identical PD controller design scheme for the three-pole hybrid-type AMB recently developed in the laboratory, which consists of three permanent magnets, providing bias flux, three Hall diodes, measuring rotor displacements, and ring type permanent magnet bearing, stabilizing in axial and tilting directions. Along the three physical coordinates formed by three poles, we introduce the redundant coordinate system and three identical decoupled controllers to construct linear model. The experiments are also carried out in order to verify the effectiveness of proposed controller in stabilizing the transient and steady state response of rotor.