• 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.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.374-374
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• 2000

In this paper, we developed an ANFIS controller through ES algorithm for disturbances rejection in Hot Rolling. The looper of a Hot Rolling is installed between each pair of stands and plays key roles to enhance the product quality of the strip by controlling the tension and the width of the strip. At the same time, the AGC on top of the Mill produces a strip with the desired thickness through pressing its Mill. Between both, however, interactions are caused by coupling effects among strip tension, looper angle and strip thickness. In addition, in case disturbances, it is more difficult to keep strip quantities desirable. So we present an ANFIS controller through ES algorithm which is able to identify fuzzy rule with input/output data and update itself through output errors.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.72-79
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• 2008

This paper designs a looper-tension controller for mass-flow stabilization in hot strip finishing mills. By Newton's 2nd law and Hooke's law, nonlinear dynamic equations on the looper-tension system are firstly derived, and linearized by a linearization algorithm using a Taylor's series expansion. Moreover, a tension calculation model is obtained from the nonlinear dynamic equations which is called as a soft sensor of strip tension between two neighboring stands. Next, a looper-tension servo controller is designed by an ILQ(Inverse Linear Quadratic optimal control) algorithm, and it is combined with a minimal disturbance observer which to attenuate speed disturbances by AGC and operator interventions, etc.. Finally, it is shown from by a computer simulation that the proposed ILQ controller with a disturbance observer is very effective in stabilizing the strip mass-flow under some disturbances, moreover it has a good command following performance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.168-171
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• 2003

Generally RF AGC (Roll Force Automatic Gauge Control) controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but RE AGC takes the bad effect of the roll eccentricity. The Feed-forward (FF) AGC method, which controls the next stand roll gap by the estimation of the thickness variation due to skid mark is needed to supplement the shortage of RF AGC. In this paper, an adaptive filtering method which takes account of the kind of material, the final objective thickness and the rolling speed is proposed to predict skid mark thickness variation. In addition, an improved estimation method of control point using a speedometer and looper angle is suggested. Via on line test, the performance improvement of the suggested FF AGC method is verified.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2513-2515
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• 2000

The Hot Strip Mill(HSM) process consists of reheating furnace, roughing mill, finishing mill and coiler. Reheating furnace heats slab and roughing mill, finishing mill produces strip from this slab. The quality of this production mainly depends on finishing mill, which consists of 6 or 7 stands. Between stands a looper is installed for the better material flow. Automatic gage control(AGC), speed control system and looper system, which are connected with each other, are the main control systems for HSM. The low strip tension can make a loop between stands, which can be caused cobble. On the other hand, high strip tension causes thickness and width reduction, which affects the product quality, and can lead to tear the strip, if it is too high. Because of it, a proper strip tension is needed for better material flow: e.g. A good looper control system is substantial for the better production quality. What is handled in this paper is, the looper controller, which is developed to minimize the fluctuation of width of strip by maintaining an appropriate strip tension between stands and to achieve the stability of the looper control system. And its performance compared with a conventional PID controller is also discussed. The difficulties associated with the maintenance of the constant tension are described.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.40-40
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• 2000

Generally a RF AGC controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but these can not be classified. The Feed- forward AGC method, which controls the next stand roll 9ap by estimation the skid mark of the previous stand output thickness is needed to supplement the shortage of RF AGC. In this paper, an improved filtering method of skid mark which take account of the kinds of materials, the final objective thickness and the roll speed is proposed, In addition, an improved estimation method of control point using the speedometer and looper angle is suggested, Via simulation, the performance improvement of the suggested FF AGC method is verified.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.735-741
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• 2015

In this paper, we suggest a dimensional controller to produce a different thickness strip without adding production facilities at the same steel. We describe the model for the non-linear thickness and speed setup, and drive a variation of the speed and thickness with Talyor expansion. The control algorithm is composed of 8 steps and the transient condition is added in order to maintain a mass flow between stands. A simulator is developed in order to verify the algorithm, and includes a non-linear rolling model, the tension model, AGC model, the disturbance model, and so on. From the simulation results by disturbances, we show that the thickness, tension and looper angle are converged to the set condition when we change the rolling conditions.

• Transactions of Materials Processing
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• v.8 no.1
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• pp.65-77
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• 1999

In recent years, the quality requirements from the customers of hot rolled steel strip have been steadily increasing in diversity and strictness. To meet these quality requirements as well as to improve productivity, steel mills have been doing their efforts for developing high performance Automatic Gauge Control (AGC) system. However, it is very time consuming and also needs a lot of money to develop the new technologies of AGC in actual mill. So, there has been a demand for developing the Dynamic Hot Rolling Simulator since late 80's. It is a kind of software packages and can analyze the dynamic behaviors of hot finishing rolling process without laborious experiments in actual mill. It can also be used as a designing tool of Automatic Gauge Controller. In this work, the Dynamic Hot Rolling Simulator which is applicable to 6 sands hot strip mill rolling was developed. The MATLAB with SIMLINK was used as a software developer for making the main part of simulator because it is very powerful tool for modeling, integrating, controller design, and simulation. In this paper, the structures and the mathematical models of the simulator were briefly described and the results of simulation on the transient phenomena of hot rolling process with actual mill data were also presented.