• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.150.5-150
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• 2001

This paper deals with a modified repetitive control method for compensating automatic gauge control (AGC) to reduce the effect of skid mark which directly influence the quality of products in plate mill process. Since the skid mark on the plate have thermal difference, it makes a different stretching rate and deflection of thickness. Firstly, the (AGC) system and the plate mill process are described by considering function in each control levels. The skid mark of the plate in practical control fields is shown. Also, its frequency variation is given by on-line FFT analysis method. Secondly, a key idea of the modified repetitive control method with time varying period disturbance is represented and compared with standard repetitive control method. Lastly, in simulation ...

• 제어로봇시스템학회논문지
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• 제15권3호
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• pp.330-336
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• 2009

This paper studies on the new control algorithm for the mass-flow stabilization in strip head part of a hot strip mill. A new strip tension model in the strip head part is derived using the current deviation of two neighboring stands. The current deviation means a difference between a measured current and a lock-on current, where the lock-on current is set up when a strip tension or a looper angle reaches each target value or time is about 0.4sec, respectively. On the basis of the tension calculation model, a mill velocity of a backward stand is controlled to stabilize a strip mass-flow by PI control algorithm. Therefore, the mass-flow control for strip head part is executed from a metal-in time into a foreward stand till the looper works normally. It is known by the results of a computer simulation and an experiment that the proposed control algorithm is very effective in stabilizing the mass flow of the strip head part.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.180-180
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• 2000

The shape of cold strip for the stainless process has been become issue in quality recently, and hence POSCO (Pohang Iron & Steel Co., Ltd) developed an automatic control system for strip shape in the sendzimir mill. The strip shape is measured by an outward measuring roll and is controlled by As_U roll and first intermediate roll. As_U roll consists of 8 saddles, which are controlled vertically. The fist intermediate rolls, which are controlled horizontally, consist of two pairs of rolls up and down. A developed shape control system is applied to real plant by using fuzzy logic and neural network method to control actuators; As_U roll and first intermediate roll. This system composes mainly of three parts as a real-time system, input to output conditioner board, and man-machine interface. The actual shape is recognized by neural network and converted into symmetric shape. The fuzzy controller, based on the shape from neural network and sensor, controls positions of the As_U roll and first intermediate roll. This paper verifies the shape controller performance. The experiments are made on line for the sendzimir mill. The shape control performance shows very efficient for the target tracking, shape symmetry, and fluctuation of shape.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1072-1075
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• 1996

In hot rolling process at steel plant, cooling of the rolled strip at the exit of the rolling mill is one of the most important processes that would decide the quality of products. To guarantee the thermal equity over the strip, the device called an edge-masking unit is being used. That is installed between the strip and the sprayers to cover the side edge of the strip from spraying water. The accuracy of positioning the bracket is the key to this operation. A machine vision technique can be applied to measure the position of the side edges before an as-rolled strip enters into the cooling facility to rectify the error of preset position of the bracket. This paper shows the simulation result of applying the machine vision technique to measuring the position of a strip and suggests the solution for the target.

• 소성∙가공
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• 제25권1호
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• pp.56-60
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• 2016

Precise prediction and control of the strip profile is crucial for automatic process set-up and operation of a hot strip mill. In the current study, we present the effect of post-deformation on the steady-state strip profile. The process was simulated by a 3-D elastic-plastic finite element (FE) analysis. Comparisons are made between the strip profile measured at the roll exit and the steady-state strip profile. The results raised an issue with regard to the importance of taking into account the effect of post-deformation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.66.5-66
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• 2002

Flatness of strip at aluminum cold rolling is one of the important quality parameters of rolled products. The reasons for this are perhaps obvious: for many of the end uses, subsequent processing requires a flat product poor flatness on-line can lead to reduced running speeds and hence to lower production levels. Amongst the reasons for lower running speeds is the increased risk of strip breaks. The Alcan Ulsan plant developed an automatic flatness control system on conventional four high mills for a year. This system compose of three parts as Intel RMX 3.3 operating system, advanced techniques, and flatness error analysis system. Strip flatness be measured by air bearing roll, passing the s...

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.378-382
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• 2004

A study was performed for verification of creation mechanism of turn down mark in thick plate. The roll mark was produced by plate bending when the front of plate was collided with roller table rolls. Various process conditions which are temperatur distribution along the thickness direction of plate, pass line, and reduction ration were investicated. These process conditions affected the amount of plate bending and were a major cause of turn down mark.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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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.

• 소성∙가공
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• 제17권4호
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• pp.272-277
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• 2008

A constitutive equation of the electrical steel strip used for a raw material of transformer is proposed. The stress-strain behavior of electrical steel strip is quite different from that of common carbon steel and/or alloy steel. A series of tensile tests were performed with the specimens made from cold rolled strip. Several thicknesses of the strip were produced by a two-high (with upper and lower rolls) cold rolling pilot mill as reduction ratio increases from 10% to 90%. Its initial thickness of the strip was 2.5mm. Tensile specimens are cut out from the cold rolled strips. Mechanical properties of the steel are examined through rolling direction. Ramberg-Osgood model and the proposed equation are combined to describe the total behavior of stress-strain including instability region. The stress-strain curves calculated from the present constitutive equation are compared with those from experimentally obtained at each test condition of reduction ratios of specimen. Results show that the predicted stress-strain curves are in overall in a good agreement with measured ones.

• 조명전기설비학회논문지
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• 제15권1호
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• pp.59-69
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• 2001

본 논문에서는 압연공정에서 편심을 검출하고 편심의 원인을 진단할 수 있는 알고리즘을 제안한다. 설계된 기법은 대부분의 압연공정에 이미 설치되어 있는 로드셀과 타코메타의 출력 신호만을 사용하며, 추가적인 센서를 필요로 하지 않는다. 편심 신호의 검출은 중심주파수가 회전속도에 따라 변화하는 6개의 디지털 대역 통과 필터의 출력을 조합하여 이루어진다. 추출된 편심 관련 데이터로부터 편심의 원인을 진단하는 기능은 적절한 변수를 정의하여 구현되었다. 모의 실험은 세 가지 경우에 대해 행해졌는데, 롤의 일부분이 마모된 경우, 회전축이 롤의 중심과 일치하지 않는 경우 및 두 가지 원인이 복합된 경우 등이다. 모의 실험 결과는 제안된 알고리즘에 의해 모든 경우에 편심의 진단이 가능함을 보여준다.