• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.41-50
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• 2021

In this study, the flow path width (Gap Size), which is the flow path of fluid, was selected differently among various factors that determine the Ccontrol Force of MR damper, and the change of Control Force was confirmed accordingly. For this purpose, two MR dampers with a Gap Size of 1.0mm and 1.5mm were fabricated, respectively, and dynamic load experiments were conducted according to changes in applied current and vibration conditions The experimental results showed that the minimum Control Force was 3.2 times higher than 1.5mm in the case of 1.0mm Gap Size, and the maximum Control Force was 2.3 times higher than 1.5mm in the case of 1.0mm Gap Size. In addition, the increased width of the Control Force according to applied current was 34N for Gap Size 1.0mm, and 12.7N for Gap Size 1.5mm. As the gap Size increased, the overall Control Force and the increase in the Control Force by the applied current decreased. Next, the dynamic range, which is a performance evaluation index of the semi-active Control device, was 2.3 on average under 1.0mm condition and 2.8 on average under 1.5mm condition, confirming the possibility of utilization as a semi-active Control device.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.45-56
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• 2002

A pneumatic servo system requiring a fine gap control in a photo-electric sensor which is used for a LCD array detection device is introduced. The gap controlled by the pneumatic servo system remains within around 50~80 ${\mu}{\textrm}{m}$, and the system possesses an effect to eliminate undesirable particles on the LCD plate by blowing air out. The air flow rate is initially controlled by a servo valve and expanded by a booster valve, thus the controlled air pressure contributes to maintaining an appropriate gap between the LCD plate and photo-electric sensor An air floating plate of two degrees of freedom is designed and fabricated, and a fine tilting motion control is also implemented by assigning different gap commands. The pressure control and direct gap control are proposed, and each performance is verified experimentally.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1469-1472
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• 1996

Hydraulic Hot Strip Mill (HHSM) rolls materials whose size and stiffness are various. So a roll gap controller for HHSM was designed using TDC(Time Delay Control) method. The performance of the roll gap control was evaluated through computer simulations. The simulation results indicate that TDC method show excellent robustness and tracking properties against PID control method in various rolling conditions.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.111.2-111
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• 2001

The research focuses on controlling a gap to measure the surface defect in semi-conductor fabrication device. The measurement is available accompanying a near field image gap control. In this article, a pneumatic servo system is adopted for the near field gap control. The advantage of the pneumatic servo system is on the preventing the possibility of contacting the device to the wapper surface, fence arising fatal damage. Furthermore, the air from the pneumatic system blows the some particle on the wapper during controlling. The target gap is less than 20 $\mu$m and the gap should keep same amount while the device moves around the surface. The experiment by the pneumatic servo control system is done by employing a simple PID control, and the tracking performance is remarkably verified. The target gap is set from 10 $\mu$m to 100 $\mu$m ...

• Journal of Digital Convergence
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• v.16 no.12
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• pp.309-315
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• 2018

In this paper, propose an efficient arc detection and control method to achieve fast machining speed, improved precision and surface roughness in discharge machining, especially for carbide and hard material processing and metal processing using discharge phenomenon as energy. A single discharge waveform is divided into three sections of Td (Time-Delay), Ton (Time-on) and Toff (Time-off) and the gate control timing is simulated using the HDL language. In this paper, we analyze the effect of the gap between the electrode and the workpiece on the machining results by determining the operation of the servo mechanism by sampling the Td section through the comparator circuit. As a result of the analysis, the Td section of the formed waveform was more precisely sampled at a high speed and the results were improved when applied to the gap control between the electrode and the workpiece.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.29-29
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• 1992

Interest in process control has rebounded from an all-time low in the mid-1970s, with a new focus on bridging the gap between academic theory and industrial practice. Since then, much progress has been made in the new generation of process control theory to bridge this gap. This review summarizes the recent advances and cur-rent problems in process control on a qualitative level.

• ICROS
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• v.12 no.1
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• pp.44-46
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• 2006

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.578-586
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• 2009

Recently, horn-type rudders are generally being used at high speed container ships and are frequently suffering from the cavitation occurs on the rudder surface in the vicinity of the gap between the horn and rudder plate. In the present study, a fluid supplying device is employed as to decrease the gap cavitation of the horn-type rudder. The device is devised to inject the water against the pressure side through the nozzle installed inside of the gap to control the gap flow. Numerical calculations are performed to investigate the effectiveness of the device and the results show that the device can noticeably reduce the gap cavitation. The rates of water injection for achievement of the maximum retardations of gap flow are also sought.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1141-1146
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• 1993

The problem of tension control in metal-strip processing line is discussed. A new mathematical dynamic model which relates tension change, motor-speed change and roll-gap change is developed. Through the computer simulation of this model, parameter sensitivity, the tension transfer phenominon, and static and dynamic characteristics of strip tension were studied. Guidelines are developed to help one selecting locations of the master-speed drive in multi-drive speed control for tension adjustment and reducing the effect of interaction between tension and roll gap control.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.327-327
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• 2000

Derivation of a slab dimension from the desired tolerance degrades the product quality, resulting in significant yield loss by trimming. This necessitates the dimensional control system to be operated in tighter dimensional accuracy. This paper presents an integral approach to a dimensional control system design taking into account the interaction between the edging process and the gap rolling process. To investigate the effects of each process controller, a simple PID controller is adopted as a preliminary study. The control performance is analyzed in detail in terms of the system response accuracy for various operating conditions.