• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.541-545
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• 1996

In this paper, The performance and functions of automatic flatness control system installed on the 4 hi-reversing mill and has been investigated under actualconditions. A new automatic flatness control system incorporates a measuring roll for measurement and correction calculations, hydraulic roll benders, selective roll cooling, and a programmable controller for interface and data logging. The test results are as following. The more the exit steel strip thickness is thick, the smaller the I value, and the more it is thin, the larger the I value. And, a complex distribution of strip tension was controlled, for example, not only a quarter buckle but also a simple center wave and edge wave. Because the tension deviation is larger at acceleration speed and deceleration speed than steady speed, so automatic flatness control system of contact type is better to adopt over 450 m/min, automatic flatness control system reduces rapidly large flatness deviation. The maximum I value of strip has been decreased to 13 I, and defects caused by poor flatness have been drastically decreased. And coolant temperature for work roll cooling system on the automatic flatness control system is better to adopt about 50-55 .deg. C.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1680-1689
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• 2002

This paper studies on the design of a looper control system for hot strip mill finisher using ILQ(Inverse Linear Quadratic optimal control) control method. The loopers are placed between each rolling stands and looper control plays an important role in regulating strip tension. The strip tension is controlled by raising and lowering the looper and by changing the speed of main work rolls. Firstly, it is shown from a nonlinear dynamic simulation that the strip tension is more influenced by difference of rolling speed than that of the looper angle. Secondly, a servo controller of the looper is designed using ILQ control method of which the characteristics and algorithms are simply introduced. Finally, the performances of the ILQ servo controller are compared with those of the LQI servo controller from computer simulation. In result, it is shown that the proposed ILQ servo controller has the better performances and robustness far parameter perturbations and disturbances than those of LQI controller.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.932-938
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• 2009

As a stringing troy wire is installed by manual operation, it is necessary to scheme the automatic system for stringing troy wire. To accomplish a task of this kind, in this paper an approach to designing controllers for the hybrid Position/Tension control of a stringing troy wire is presented. Position control system is designed based on equation of dc motor and motion equation of robot, it is controlled by feedback with a detected speed dc motor. Tension control system is designed based on equation of ac servomotor for generating torque and dynamic equation of a troy wire, it is controled by feedback with a detected tension. The control parameters is determined by simulation in independence operation of each system. To suppress a mutual interference that the disturbance occur in operating of two task at same time. Dynamic hybrid control is proposed by feed forward compensator with a disturbance accelerator and a step torque at start. The operation of proposed system is simulated and experimented, results is verified the utilities.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.10
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• pp.701-707
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• 2000

This paper proposes a tension control to compensate friction loss using on-line friction torque observer for a continuous strip processing line. Friction loss of roller results in significant deviation of strip tension, accordingly it has an influence on the operation of other adjacent rolls. To avoid tension variation of the strip, a friction torque observer is designed in adjacent roll, which operates in speed control mode. The observed torque is added to the torque limit reference of the pay-off reel for on-line compensation of both friction loss and acceleration/deceleration torque at the same time. The simulation and experimental results show improvement of tension control performance by the proposed friction compensation method.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.873-878
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• 2007

Stability of high-speed roll-to-roll printing machines is one of the most important factors that are required for the printing machines to operate properly and to obtain reasonable printing performance. This paper proposes a new model for the web-tension system of a high-speed gravure printing machine considering span-length variations due to dancer rollers, and analyzes the stability of plant dynamics of the printing machine using the proposed model. Span-length variations due to dancer motions are considered for the modeling of plant dynamics in two ways; one is to include the effect of span-length variations without considering dancer inertias and viscous frictions, and the other is to include the effect of span-length variations with considering dancer inertias and viscous frictions. The stability of the plant model is analyzed for various web-speeds using the eigenvalues of the linearized model about operating points.

• Journal of IKEEE
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• v.11 no.4
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• pp.213-218
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• 2007

We consider a web transport system. The objective of this paper is to design the output feedback controller such that the controller can track a desired tension and processing speed on web transport system. We propose the new design method using observer and feedback linearization technique. The proposed method use a nonlinear feedback to transform to linear system and high gain observer to estimate the state value. We show that the proposed controller can achieve the control object using only output. We show a performance of controller via the simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.9
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• pp.894-898
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• 2009

In a post printing section of roll to roll printing systems, scratch problem is the major defects. The functional qualities such as conductivity, mobility could deteriorate because of the scratch defect. In general, the scratch of the printed pattern on the flexible substrate was induced from a contact between rolls and printed pattern in the post printing section. In this paper, for non-contacting transfer of a moving web, a mathematical tension model has been developed considering strain due to air floatation and the proposed mode has been validated by numerical simulation. Additionally, the correlation between floatation height and speed compensation to control the tension and register are investigated. On the basis of the proposed model, a guide line of speed control in R2R printing system is presented to guarantee the non-contact between rolls and R2R printed pattern on the flexible substrate.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.194-199
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• 1992

In this paper, each section of an Electrolytic Tinning Line is mathematically modelled with the coupling effect accounted for. Based on the modelling, PI and feedforward controllers are designed for speed control or tension control of each section of the process line. It is shown through simulatios that the tension of the stip is controlled precisely along the entire line and the contituety of the process is insured when using the efficient control of loop towers.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.9
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• pp.869-874
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• 2015

We developed an LSDC (Load Shift and Load Distribution Control) technology in order to improve coil quality and productivity by reducing tension fluctuation especially for the tail of the strip in the down coiler in hot strip mills. To adapt the new controller, the torque and speed distribution between the zero pinch roll, pinch roll, and mandrel are needed. The proposed controller is a combination of an LSC to share the tension between the mill stand and the mandrel, and an LDC to shift the torque load from the zero pinch roll to the pinch roll. From the simulation, the proposed controller is verified under the torque disturbance. Using a field test, the torque deviation decreased by nearly 50% through utilization of the LSDC control.

• Journal of Biosystems Engineering
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• v.37 no.2
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• pp.106-112
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• 2012

Purpose: A lab-scale timber carriage using a servo motor system was built. When two motors move a carriage, wire tension is changed according to the different line speeds caused by a wire drum's changing diameter, leading to inappropriate traveling characteristics of the carriage. In order to overcome this problem, PID Control was used to control the motor speed. Methods: Ziegler-Nichols method was used to determine PID gains. Results: The initial PID gains were 1.8, 0.025, and 0.006, respectively, and optimal gains of 1.4 and 0.010 for P and I gain were obtained experimentally. Conclusions: The results showed that constant wire tension could be maintained by controlling the speed of the motor using PI control. Overshoot occurred at initial motor operation due to vibration and elasticity of the wire itself.