• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.1
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• pp.24-30
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• 2008

A simulation of hot strip finishing mill automatic gauge control (AGC) system is built, which is divided into four modules such as rolling mill system, AGC module, looper system and strip model. The rolling mill system is built by mechanism modeling, the looper system and strip model are built by function modeling, and the AGC model is tried to use intelligent control of a multi-function AGC system. The target is attempted to use this simulation object to minimize finisher exit strip thickness deviation resulting from strip entry thickness disturbance and rolling force deviation. Simulation results show that the result of this AGC/LPC synthetical system module simulation is quite close to the actual result. The simulation system can also analyze most kinds of disturbance which affect the rolling process. It is proved that the system can represent practical situation of hot strip finishing mill process control, and be used as a basic platform of research and development for researcher and engineer.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.11
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• pp.925-936
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• 2003

The manipulability analysis of the parallel-type rolling mill proposed in Hong et al. [1] is re-visited. The parallel rolling mill uses two Stewart platforms in opposite direction for the generation of 6 degree-of-freedom motions of each roll. The objective of this new parallel rolling mill is to permit an integrated control of the strip thickness, strip shape, pair crossing angle, uniform wear of rolls, and tension of the strip. New forward/inverse kinematics problems, in contrast with [1], are formulated. The forward kinematics problem is defined as the problem of finding the roll-gap and the pair-crossing angle of two work rolls for given lengths of twelve legs. On the other hand, the inverse kinematics problem is defined as the problem of finding the lengths of twelve legs when the roll-gap, the pair-crossing angle, and the position and orientation of one work roll are given. The method of manipulability analysis used in this paper follows the spirit of [1]. But, because the rolling force and moment exerted from both upper and lower rolls have been included in the manipulability analysis, more accurate results than the use of a single platform can be achieved. Two. kinematic parameters, the radius of the base and the angle between two neighboring joints, are optimally designed by maximizing the global manipulability measure in the entire workspace.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.93-95
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• 2007

Studies on ski-end shape control at the top end of rolling plate in heavy thick plate mill by using FEM analysis and measuring system have been performed. Plate shape behaviour at the top-end on rolling by the two different methods in finishing rolling process has been observed. One is to minimize the height of ski-end by using pass line based on the relational model between shape factor and pick-up and the other one is to prevent turn down problem caused by the impact between table roller and down bended plate on rolling by using roll speed difference. To minimize the height of ski-end, the prediction models based on the FEM analysis and measuring data was developed. The control method of ski - end shape on finishing rolling process was applied in actual mill and the height of ski-end was reduced by about 50% compared with conventional operation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.59-64
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• 2006

The automation of hot rolling process requires the developments of several mathematical models for simulation and quantitative description of the industrial operations involved in order to achieve the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties). The mathematical modeling of hot rolling process has long been recognized to be a desirable approach to investigate rolling operating practice and design of mill requirement. To achieve this objectives, a new teaming method with neural network to improve the accuracy of rolling force prediction in hot rolling mill is developed. Also, Genetic Algorithm(GA) is applied to select the optimal structure of the neural network and compared with that of engineers experience. It is shown from this research that both structure selection methods can lead to similar results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1689-1699
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• 1990

Sendzimir rolling mill is widely used for rolling hard materials such as stainless steel due to its small work roll diameter and shape controllability using two effective actuators, AS-U-Roll crown adjustment and lst. intermediate roll shifting. However, in comparison with 4-high or 6-high mills, it is noteasy to get good strip or excellent flatness because Z-mill has small diameter of work rolls which are easily deformed by load. A new mathematical model based on the method of dividing roll and strip into multo-portions was used to develop strip profile prediction software. Using the developed software, several influencing factors related to rolled strip profile for Z-Mill were tested analytically and characterized for the effective shape control. The effects of adjusting shape control actuators of Z-Mill on strip profile were also examined and discussed in detail.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.723-727
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• 2003

In this paper, two methods are discussed for good rolling force prediction in a plate mill. One is about the development of a long and a short learning scheme using a Neural Network for normal rolling and the other is about a mathematical model improvement by considering microstructural changes for controlled rolling. The research results are implemented in a on-line system of Pohang Works in POSCO and the field tests have showed that the prediction accuracies of rolling force are highly improved.

• Transactions of Materials Processing
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• v.11 no.1
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• pp.24-35
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• 2002

Recent trend and future prospect of flat rolling of steel has been summarized based on the earlier reports. Key technology in the plate rolling is to have ultra fine microstructure having high resistance against crack propagation during application. Heavy accelerated cooling facility and high power rolling mill will be helpful to develope the high toughness steel. Precise modeling of properly prediction based on deformation and transformation imposed on microstructure of steel during processing is highly anticipated. For the hot strip rolling process, new trend is lies on the production of ultra-thin gauged hot strip to substitute cold rolled strip. For the substitution of cold rolled strip into hot rolled strip widely, high formable property of hot strip is highly required. For the formabilit, the ferritic rolling of extra low carbon steel under high lubricated condition is essential. Recently introduced semi-continuous thin slab and rolling mill line is very plausible to develope those kinds of products easily In the view groin facility combination. New idea to modify the existing continuous hot strip mill line to produce the ultra thin-gauged hot strip in an economic way is suggested in this report.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.368-373
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• 2003

A major concern at present is the simultaneous control of transverse thickness profile and flatness in the finishing stages of hot rolling process. The mathematical modeling of hot rolling process has long been recognized to be a desirable approach to investigate rolling operating practice and the design of mill equipment to improve productivity and quality. However, many factors make the mathematical analysis of the rolling process very complex and time-consuming. In order to overcome these problems and to obtain an accurate rolling force, the predicted model of rolling force using neural networks has widely been employed. In this paper, Radial Basis Function Network(RBFN) is applied to improve the accuracy of rolling force prediction in hot rolling mill. In order to verify and analysis the performance of applied neural network, the comparison with the measured rolling force and the predicted results using two different neural networks - RBFN, MLP, has respectively been carried out. The results obtained using RBFN neural network are much more accurate those obtained the MLP.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.6
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• pp.29-33
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• 2004

A major concern at present is the simultaneous control of transverse thickness profile and flatness in the finishing stages of hot rolling process. The mathematical modeling of hot rolling process has long been recognized to be a desirable approach to investigate rolling operating practice and the design of mill equipment to improve productivity and quality. However, many factors make the mathematical analysis of the rolling process very complex and time-consuming. In order to overcome these problems and to obtain an accurate rolling force, the predicted model of rolling force using neural networks has widely been employed. In this paper, Radial Basis Function Network(RBFN) is applied to improve the accuracy of rolling force prediction in hot rolling mill. In order to verify and analyze the performance of applied neural network the comparison with the measured rolling force and the predicted results using two different neural networks-RBFN, MLP, has respectively been carried out. The results obtained using RBFN neural network are much more accurate those obtained the MLP.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.452-456
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• 1999

Newly constructed plate shape control system, using attached shape measuring instruments and work roll bender, was put in service in No. 2 Plate Mill, POSCO. Recently, customers demand the improvement of flatness and plate crown accuracy. Many competition Plate Mill introducted shape control system, for example, pair cross mill, work roll bender which includes shape measuring instrument and shape control mathematical models, and No. 2 Plate Mill, POSCO introducted work roll bender and shape measuring instruments. This report describes the properties of No. 2 Plate Mill shape control system and work roll bender.