• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.05a
• /
• pp.225-229
• /
• 2003

When hot strip is trimmed in the side trimming process at the entry side of tandem cold rolling mill, due to bad quality of trimming face and burr, product quality(saw ear)becomes so bad that it causes drop of yield and claim from customers. Therefore, it was examined that applying ultrasonic vibration is an effective method to improve quality of strip trimming face and decrease burr magnitude by decreasing shear force acting between strip trimming face and knife in side trimming process of cold rolling.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10a
• /
• pp.525-530
• /
• 1992

This paper deals with an exit strip gauge controller design for a cold rolling mill process with one input and two outputs. In order to attenuate the exit strip gauge variation caused by the Back-up roll eccentricity and the entry guage variation, an H$_{\infty}$ controller design methodology is used to keep the frequency weighted mixed sensitivity function small. Effectiveness of the proposed controller is demonstrated by a computer simulation..

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.534-539
• /
• 1986

This paper considers the ring rolling process contorl and treats the problem of controlling the pressure roll and conical roll motion which critically affects final quality of the rolled products. Since the process dynamics reveals nonlinear characteristics and parameter uncertainty, an adaptive control scheme was applied. The results show that this proposed adaptive control scheme can produce rolled rings of closer dimensional tolerances as compared with nonadaptive control system.

• Journal of the Korea Society for Simulation
• /
• v.18 no.3
• /
• pp.23-34
• /
• 2009

In the railroad rolling stock depot, long-term maintenance tasks is done regularly every two or four year basis to maintain the functionality of equipments and rolling stock body or for the repair operation of the heavily damaged rolling stocks by fatal accidents. This paper addresses the computer simulation model building for the rolling stock maintenance shop for the CDC(Commuter Diesel Car) and Generator Car planned to be constructed at Daejon Rolling Stock Depot, which will be moved from Yongsan Rolling Stock Depot. We evaluated the processing capacity of two layout design alternatives based on the maintenance process chart through the developed simulation models. The performance measures are the number of processed cars per year, the cycle time, shop utilization, work in process and the average number waiting car for input. The simulation result shows that one design alternative outperforms another design alternative in every aspect and superior design alternative can process total 340 number of trains per year 15% more than the proposed target within the current average cycle time.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.10a
• /
• pp.194-194
• /
• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.11a
• /
• pp.217-218
• /
• 2007

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.243-247
• /
• 1991

A roll eccentricity controller for a tandem cold rolling process is designed to attenuate the outlet thickness deviation due to roll eccentricity. In order to design the controller, the excess stability margin is maximized by solving a standard H.inf. optimization problem under the requirement that ensure disturbance rejection for a class of disturbance. Robust performance of the proposed controller is checked by a computer simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.10a
• /
• pp.271-272
• /
• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.1319-1320
• /
• 2011

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.10
• /
• pp.1006-1012
• /
• 2010

The hot rolling process ranks the highest position for production in steel making process. The hot strip manufacturing processes consist of the reheating furnace, roughing and finishing mill and coiler. The reheating furnace heats the slab. The roughing and finishing mill produce the hot strip from slab. The hot strip quality mainly depends on finishing mill, which consists of 4-high 7 stands. The looper is installed between stands and is used for controlling the strip tension by the looper angle for better material flow. It is difficult to control the strip tension with the coupled looper system from interaction between the looper angle and strip tension. Too much deviation of strip tension severely affects the poor width quality of the hot strip. It is important to control simultaneously both the looper angle and strip tension with each of their target values. This paper proposes the fuzzy tension control, which is developed to minimize the width deviation of the hot strip by maintaining the proper strip tension between stands and to achieve the stable operation of the coupled looper system. The fuzzy tension control performance is compared with the conventional PID control by experimental results.