Tension Control Performance Research Articles

Advanced taper tension profile for improved control performance in roll-to-roll winding processes

Products coated with flexible film can be stored in wound rolls after the winding process. However, if the roll product experiences excessive internal stress, it can lead to various defects in the coated layer. To alleviate the stress within the wound roll, a taper tension profile is utilized to progressively reduce tension as the winding length increases. As a substantial amount of web is wound onto the core, the moment of inertia of the wound roll increases. It has been observed that, as the winding length increases, the tension control performance of the taper tension tends to deteriorate. We propose an advanced taper tension profile to enhance tension control performance and validates the effectiveness of this profile through winding experiments. It was observed that, compared to the parabolic taper tension, maximum tension error could be reduced by approximately 16.1 % throughout the winding process. This reduction in tension error enables the preservation of the radial stress reduction effect of the taper tension, resulting in a 13.3 % decrease in the maximum radial stress compared to the parabolic taper tension. The proposed taper tension profile contributes to a more uniform quality of the coated layer, especially as the maximum winding length is extended.

Research on anti-vibration tension control based on self-coupling fractional-order PID

Constant tension control is essential for excellent winding quality. However, the system’s nonlinearity and external disturbance make it challenging to guarantee tension control accuracy with conventional control methods. Thus, a self-coupling fractional-order proportional–integral–derivative (SC-FOPID) control scheme combined with a disturbance observer is proposed to enhance the system’s anti-vibration performance. The fractional-order dynamic model of the unwinding roller and swing rod is established by analyzing the tension mechanism. Based on deliberate analysis and calculation, the vibration shock signal can be decomposed into periodic sinusoidal disturbance and bounded noise approximately. As such, an output-based anti-vibration method using a fractional-order model can be realized, where a back recursive disturbance observer is designed to estimate the periodic component. Simultaneously, the bounded noise exhibited in vibration can be attenuated by the SC-FOPID controller. The stability is guaranteed using the Lyapunov theorem, and the simulation results show the proposed method’s effectiveness in improving the tension control performance.

Control methodology for tensioned web considering thermal behavior in roll-to-roll manufacturing systems

The roll-to-roll manufacturing system is utilized for processing flexible webs into functional films, offering high productivity through continuous multi-stage processing. In the converting span, which encompasses coating, printing, and drying processes, precise tension control and appropriate tension settings are crucial to ensure the quality of the final product. Particularly during the drying process, where solvent removal occurs, thermal deformation of the web induces additional elongation, amplifying the impact of tension on coating layer quality and printing patterns. Consequently, the drying process necessitates more accurate tension control compared to other span, necessitating the application of feedforward control that considers web thermal deformation. However, the current tension control logic employs an imprecise temperature distribution within the dry span as an input, resulting in inadequate tension control performance and defects such as uneven coating layers and registration errors. This research presents the development of a feedforward tension controller that employs Finite Element Method (FEM)-based web temperature distribution inputs to enhance tension control performance during the drying span. The tension control performance was compared and analyzed based on the drying span web temperature prediction method, affirming that higher accuracy in predicting the web temperature distribution leads to improved tension control performance. Experimental results from an industrial-scale roll-to-roll system demonstrate that the proposed model enhances tension control accuracy during the drying process by 27.76% compared to the existing control logic. Furthermore, the effectiveness of the tension control logic in enhancing the surface quality of functional layers was confirmed through surface quality analysis using solid oxide fuel cell (SOFC) electrolyte layers.

Experimental Validation of High Precision Web Handling for a Two-Actuator-Based Roll-to-Roll System.

In this paper, experimental validation of high precision web handling for a two-actuator-based roll-to-roll (R2R) system is presented. To achieve this, the tension control loop is utilized to regulate the tension in the unwinder module, and the velocity loop is utilized to regulate the web speed in the rewinder module owing to the limitation of the number of actuators. Moreover, the radius estimation algorithm is applied to achieve an accurate web speed and the control sequence of the web handling in the longitudinal axis is developed to manipulate the web handling for convenience. Having these, the tension control performances are validated within ±0.79, ±1.32 and ±1.58 percent tension tracking error and 1.6, 1.53 and 1.33 percent web speed error at the speeds of 0.1 m/s, 0.2 m/s, and 0.3 m/s, respectively. The tension control performance is verified within ±0.3 N tracking error in the changes of the reference tension profile at 0.1 m/s web speed. Lastly, the air floating roller is used to minimize the friction terms and the inertia of the idle roller in the tension zone so that tension control performance can be better achieved during web transportation.

Synthesis and application of PHEMA-b-PMPS copolymers using RAFT polymerization

Poly (2-hydroxyethyl methacrylate)-block-poly (3-(methacryloxy)propyl trimethoxysilane) (PHEMA-b-PMPS) was obtained through the reversible addition–fragmentation chain transfer polymerization (RAFT) and analyzed using 1H NMR, FTIR, GPC and DSC techniques. Under the polymerization condition, the Mw /Mn value of the well-defined block copolymers was around 1.1–1.2. These silicon-containing polymers possess many applications. First, this amphiphilic block copolymers shown good ability based on its surface tension control performance. Then, the self-assembly behaviors of block copolymer in the mixed solvents were studied. DLS results have shown that the aggregates could self-assemble into core–shell particles. These core–shell structure and resulting hybrid core–shell nanoparticles were analyzed by TEM. Finally, the biocompatibility of the copolymer hydrogels was verified by in vitro cell viability studies on fibroblasts L929.

Optimal analysis and application of the warp tension control system for a rapier loom

Traditional proportional–integral–derivative (PID) control performance optimization is an essential method to improve a loom’s warp tension control performance. This work proposes an improved genetic algorithm optimized PID control scheme to overcome the decline in control performance of the traditional PID control algorithm in a loom’s warp tension control system. Through the decoupling analysis of loom motion mechanism, the establishment of warp tension model and the optimization of fitness evaluation mechanism of genetic algorithm can effectively overcome the problems of local optimal solution and algorithm degradation of genetic algorithm. Simulation experiments were carried out with the traditional PID, the integral separation PID, and the genetic PID in warp tension control. The results show the advantage of the genetic-PID algorithm to control warp tension stability. Ultimately, according to the functional characteristics of the loom mechanism, a tension control platform for experimental studies was established. The test results show that the maximum fluctuation range of warp tension is within [−2, +6] at the test speed of 850 rpm, which meets the requirements of long-term stable and reliable control of warp tension under different weaving conditions.

The Equivalent Sliding Mode Tension Control of Carbon Fiber Multilayer Diagonal Loom

In order to enhance the tension control performance of the carbon fiber multilayer diagonal loom, two control methods based on the yarn warping and the curling control are proposed. The tension control mathematical models of carbon fiber multilayer diagonal loom, the yarn warping control model and the curling control model, are reestablished by the force analysis of the warping and the curling systems. Some technological process movements, such as the opening and the beating-up, are regarded as the disturbances. Based on the equivalent sliding mode control theory, the tension control strategies of the warping and the curling are constructed. Lyapunov method is used to prove the stability of the systems. Simulation results show that both the two methods could control the tension of the yarn, and the control results have good robustness to the disturbances.

열연 루퍼시스템의 퍼지 장력제어

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.

A Feed-forward Tension Control in Drying section of Roll to Roll e-Printing Systems

The mathematical model for tension behaviors of a moving web by Shin (Shin, 2000) is extended to the tension model considering the thermal strain due to temperature variation in a dryer of the roll to roll systems. The extended model includes the terms that take into account the effect of the change of the Young's Modulus, the thermal coefficient, and the thermal strain on the variation of tension. By using the extended tension model, a new tension control method is suggested in this paper. The key factors of suggested tension control method include that the thermal strain of web could be compensated by using the velocity adjustment. The computer simulation and experimental validation was carried out to confirm the performance of the proposed tension control method. The results show that the suggested tension control logic improves the performance of tension control in a dryer section of the roll to roll systems.

Strip tension control considering the temperature change in Multi-Span systems

The mathematical model for tension behaviors of a moving web by Shin (2000) is extended to the tension model considering the thermal strain due to temperature variation in furnace. The extended model includes the terms that take into account the effect of the change of the Young’s Modulus, the thermal coefficient, and the thermal strain on the variation of strip tension. Computer simulation study proved that the extended tension model could be used to analyze tension behaviors even when the strip goes through temperature variation. By using the extended tension model, a new tension control method is suggested in this paper. The key factors of suggested tension control method include that the thermal strain of strip could be compensated by using the velocity adjustment of the helper-rollers. The computer simulation was carried out to confirm the performance of the suggested tension control method. Simulation results show that the suggested tension control logic not only overcomes the problem of the traditional tension control logic, but also improves the performance of tension control in a furnace of the CAL (Continuous Annealing Line).

Vibration Control of a Wire Cut Discharge Machine Using ER Brake Actuator

This paper presents vibration characteristics of a wire cut discharge machine in which an electrorheological brake actuator is used to control the wire tension. On the basis of the tension level required in the machine an appropriate size of the ER brake actuator is devised. The ER brake actuator is then incorporated into the machine and the field-dependent wire tension is experimentally evaluated. The straightness of the workpiece is also empirically investigated by changing the intensity of the electric field. In addition, the tension control performance of the discharge machine is simulated by utilizing a robust sliding mode controller.

Design and control of multispan tension simulator

In this paper, the design and control aspects of a multispan tension simulator are presented. The simulator consists of four driven rolls, including unwinder, winder, and two bridle rolls. Some relationships between design parameters and characteristics of the simulator are explained as a design guide of a multispan system. A new control algorithm of continuous load balance control is proposed for the control of speed and tension in the multispan system. The strip tension is controlled by the continuous balancing of the load torque of rolls without a tension sensor. The simulation and experimental results reveal conspicuous improvement of tension control performance by the proposed algorithm.

Improvement of Strip Thickness Accuracy by Using AC Motor Drive Systems in Hot Strip Mills.

This paper presents that, in hot strip finishing mills, AC motor drive systems improve the strip tension control performance which results in better strip thickness accuracy than DC motor drive systems.Recently the AC motors are more widely used in many industrial fields including steel making process because of their higher response of speed control, higher reliability, and easier maintenance than DC motors. Here we consider the effect of using AC motors as rolling main motors from a point of view of strip thickness accuracy. We analyse the relation between speed control response of the strip tension control system and strip thickness accuracy with use of the Bode diagram and non-linear simulation. As a result we show that the higher response of AC motor speed control system can achieve the smaller strip tension deviation, furthermore makes it possible to get higher response of gage control system which turns more accurate strip thickness.