Width Control System Research Articles

Adaptive Predictive Control of Backside Weld Width in Pulsed Gas Metal Arc Welding Using Electrical Characteristic Signals as Feedback

The control of backside weld width in pulsed gas metal arc welding (GMAW-P) is achieved with two electrical characteristic signals as feedback in the present work. The GMAW-P process is adjusted by changing the parameters of the base current period to provide the needed heat input, while the backside weld width is characterized during the amplitude-fixed peak current period. The two characteristic signals, i.e., the relative change in arc voltage and the average arc voltage during the peak current period, exhibit negative linear relationships with backside weld width and are employed as sensing signals. With these two characteristic signals as outputs, the backside weld width control system in GMAW-P is modeled and analyzed. The adaptive predictive controller is thus designed and validated in real-time control. This work provides an easily implemented way for weld geometry control in GMAW-P and thus has a practical meaning.

Design and Testing of an Automatic Strip-Till Machine for Conservation Tillage of Corn

Successive years of straw mulching and returning straw to the fields in Northeast China have made strip-tillage necessary, and reasonable strip-tillage operations can create conditions for crop growth. However, there are limited research studies on the related equipment applicable to this area. In this paper, an automatic control strip-tillage machine is designed. According to the conventional planting pattern of maize in this region, the operative processes of the machine were determined, and a suitable strip seedbed structure could then be constructed under straw mulching conditions. The type of coulters and the structural parameters of the V-type soil-crushing wheel were determined through theoretical analysis. Based on the air spring and electric linear actuator, the plowing depth control system and the straw width control system were developed, respectively, so as to improve the stability of the machine operation. Field tests showed that when the forward speed, tillage depth, and theoretical width were 6–12 km/h, 6–12 cm, and 18–24 cm, respectively, the straw clearing rate, soil crushing rate, and tillage depth and breadth stability were higher than 90%, and the soil flatness was less than 2 cm. All the indexes satisfied the agronomic and technological requirements of corn cultivation. The results of this study can provide equipment and technical support for the further popularization of conservation tillage technology.

Laboratory setup for fiber Bragg gratings inscription based on Talbot interferometer

An experimental setup for the fiber Bragg gratings (FBGs) inscription by use of Talbot interferometer has been described in this paper. A KrF excimer laser system Master Oscillator–Power Amplifier CL-7550 (Optosystems Ltd, Russia) was used as the UV radiation source in the experimental setup. In order to control laser beam quality, thus to provide FBGs effective writing, the laboratory setup includes: spectral width control system, based on Fabry–Perot interferometer; laser beam energy distribution control system; monitoring system of laser pulse energy density on the optical fiber; and control system of optical fiber to the laser beam relative position. FBGs of type I inscription results in a single-pulse and multi-pulse modes are presented.

Plate Width Control Based on Neural Network in Hot Mill

Based upon the model analysis on hot roll width control system, an online adaptive PD combined with Neural Network control method is proposed to account for the complicated process dynamics characterized by nonlinear, parameter uncertain and load disturbances etc. The NN model was introduced as a feed-forward controller to study the controlled plant inverse dynamic. The controller is independent of the exact controlled system modeling, and the control parameter can be regulated online by using the measured input/output datum based on feedback error learning method. The PD controller act as feedback one to ensure the robustness. The proposed scheme is simulated on vertical roller of hot strip mill. The control performance is analyzed in detail in terms of the system response speed and accuracy, as well as robustness to rolling temperature variation.

Weld Width Control System for Pulsed MIG Welding of Aluminum Alloy

Due to strong heat accumulation and low surface tension of aluminum alloy, weld width will become wider, even subsidence in pulsed MIG welding process of aluminum alloy at constant parameters. A variable double-pulse method for weld width control is proposed. Weld width control is realized by changing double-pulse duty cycle that is the ratio of high-energy pulse time in a double-pulse cycle to adjust heat input based on the vision sensing for weld width. A rapid prototyping control system is built on the basis of vision sensing and xPC Target real-time environment. Then variable double-pulse MIG welding process test is done and proves the feasibility of the control scheme. On this basis, weld width control test in pulsed MIG welding of aluminum alloy is carried out and obtains a good weld with beautiful formation and uniform weld width. The results show that weld width control can be realized well with the variable double-pulse method in pulsed MIG welding of aluminum alloy.

Optimization of Short Stroke Control Preset for Automatic Width Control of Hot Rolling Mill

Automatic width control is a key issue in hot strip rolling process. The edge rolling has been widely used in the roughing stand of hot strip mill to control the width of the slab. However, the edge rolling and consequent horizontal rolling will cause a significant width change in the head part and tail part of the slab, which have to be trimmed before the finishing stands. Based on the width reduction deformation curve of the head and tail along the longitudinal direction of slab, the short stroke control (SSC) technology has been developed to overcome this problem. The finite element method has been used to simulate the unsteady edge rolling process. Three short stroke control curves have been compared in order to obtain the best width control result. The optimized short stroke control curve has been applied to the automatic width control system of industrial hot rolling mill, and good performance is obtained.

Width control systems with roll force automatic width control and finishing vertical mill automatic width control in hot strip mill

This paper proposes a new width control system composed of an RF (roll force) AWC (automatic width control) in the roughing mill and a FVM (finishing vertical mill) AWC in the finishing mill which aims at obtaining the desirable width margin in the hot strip mill. The RF AWC is designed by the control model on the basis of a gauge meter equation using the roll force of the vertical mill. The FVM AWC is designed using a neural network based width prediction model to minimize a width variation between the measured width and the target value. The RF AWC and the FVM AWC combined with the conventional FB (feedback) AWC satisfy a desirable width margin. It is shown through the field test of the Pohang no. 1 hot strip mill of POSCO that the performance of the width margin is considerably improved by the proposed control schemes.

Active disturbance rejection control for hydraulic width control system for rough mill

The highly nonlinear behavior of the system limits the performance of classical linear proportional and integral (PI) controllers used for hot rolling. An active disturbance rejection controller is proposed in this paper to deal with the nonlinear problem of hydraulic servo system in order to preserve fast response and small overshoot of control system. The active disturbance rejection (ADR) controller is composed of nonlinear tracking differentiator (TD), extended state observer (ESO) and nonlinear feedback (NF) law. An example of the hydraulic edger system case study is investigated to show the effectiveness and robustness of the proposed nonlinear controller, especially, in the circumstance of foreign disturbance and working condition variation, compared with classic PI controller.

신경회로망과 퍼지 논리를 이용한 열간 사상압연 폭 예측 모델 및 제어기 개발

This paper proposes a new width control system composed of an ANWC(Automatic Neural network based Width Control) and a fuzzy-PID controller in hot strip finishing mills which aims at obtaining the desirable width. The ANWC is designed using a neural network based width prediction model to minimize a width variation between the measured width and its target value. Input variables for the neural network model are chosen by using the hypothesis testing. The fuzzy-PlD control system is also designed to obtain the fast looper response and the high width control precision in the finishing mill. It is shown through the field test of the Pohang no. 1 hot strip mill of POSCO that the performance of the width margin is considerably improved by the proposed control schemes.

Direct Width Control Systems Based on Width Prediction Models in Hot Strip Mill

In this paper, a width control system is proposed to obtain the desirable width margin of a strip in the rolling process of the hot strip mill. A simplified FEM (Finite Element Method) based width prediction model (WPM) is developed to compute the width spread at each stand. A neural network based error correction model (ECM) is also introduced to compensate for modelling errors from the simplified FEM based WPM. Input variables for the neural network model are chosen by using the hypothesis testing. In addition, the width control scheme using the simplified FEM based WPM and the neural network based ECM is proposed to achieve the desired width margin in the finishing mill. It is shown through the field test of the Pohang no. 1 hot strip mill of POSCO that the performance with respect to the width margin is greatly improved by the proposed width control scheme based on two models.

鋼板の絞り現象を利用した熱間連続幅制御方法の提案

This paper describes the new width control system that utilized the diaphragm phenomenon seen in the heat treatment process of a steel plate manufacturing process. This system derives the creep composition formula under the high temperature condition of a steel plate, designs each control system which constitutes a system and verified the possibility of this new width control system by computer simulation (1/10 scale). As a result of examining the capability of the equipment and investigating the change action of width by a numerical simulation, following result is obtained that width control is realizable on calculation. By this system, the improvement in manufacture efficiency and large cost reduction are expected since width change can carry out easily and sharply.

Threshold technology and its application for gap status detection

Process control systems of modern EDM-machines offer several opportunities for gap status detection. The method described here is the threshold technology at which the voltage course of a discharge can be classified in normal pulses, open circuits, short circuits and arcs by different voltage thresholds in combination with time recording. Especially in arc detection a new path will be treated by using a burning voltage threshold positioned slight below the effective burning voltage of a normal discharge. Its determination depending mainly from the electrode/workpiece material combination and the adjusted amperage will be described in detail. Moreover a fuzzy gap width control system will be established only based on the relative number of open and short circuits ascertained within a time period. Also in this case the threshold technology will be applied. This gets completed by a neural network. The efficiency of the different systems will be demonstrated at roughing and smoothing experiments in comparison to a ignition delay time ( t d)-based solution.

Piecewise-Linear-Gain Pulse Width Control for Precise Positioning of Structurally Flexible Systems Subject to Stiction and Coulomb Friction

Pulse width control refers to the use of a control law to determine the duration of fixed-height force pulses for point-to-point position control of a plant that is subject to mechanical friction, including stiction. A quantitative measure of the performance of a pulse width control system is introduced. Applications of this measure suggest that piecewise-linear-gain pulse width control laws will often provide better performance than constant-gain pulse width control laws. A method for designing piecewise-linear-gain pulse width control laws is introduced. The performance measure and piecewise-linear-gain control law design method are demonstrated in applications to the control of the position of the end-effector of an industrial robot.

Improved strip-width accuracy through the application of edgers in hot-rolling mills

Application of advanced edging equipment in combination with sophisticated automation and control systems is necessary for improving the width accuracy of hot-rolled strip. This paper reviews the existing edger equipment and introduces an important contribution of VAI to this problem : a non-linear automatic width control system (AWC) based on the use of short-stroke cylinders.

Chamfering Quality Control by an Industrial Robot. For the Case of Chamfering for Safety.

The study deals with the control by an industrial robot. In the study, the chamfering quality means the property of the chamfered edge shape for various functions. Especially, a for safety is discussed in the article. In order to perform by a robot, a width control system is developed to compensate positioning errors and to control the width of part. A tool path is generated on the basis of CAD data followed by conversion to a robot control command. The depth of cut at, each point calculated based on the CAD data is given to width control unit attached to the robot to realize designated shape of chamfering. From the experimental result, the system is found to have an ability of for safety.

High Accuracy Width Control System for SSM Hot Strip Mill

In compact hot strip mills, improving the accuracy of product strip width is an important factor in reducing production costs. This paper describes a newly developed width control system for the SSM hot strip mill. The features of the system are as follows: (a)Edger roll gap setup function based on accurate width change prediction, (b)Flexible learning function with classified learning result table, and (c)Dynamic control of the interstand tension between roughing stands and dynamic control for improved width accuracy in the region of variable width change at the head and tail ends of the material. Implementation of this new system has achieved a significant improvement in width accuracy.

Hydropower Station Power Joint Control Analysis and Design

A generalized model of Pulse Width Control System is given. Resulted nonlinear model is linearized. For the linearized system the stability conditions are determined. Theoretical results are used for Joint Control of a real-world hydropower station system analysis.

Automatic width control system using interstand tension in hot strip finishing mill

An automatic width control system using interstand tension in the finishing mill at Mizushima Works has been developed. Experiments show that the tension between the F1 and F2 stands can effectively control the strip width. A feedback loop is incorporated, using a width meter newly installed between the F2 and F3 stands. The average reduction of width margin for ultra-low carbon steel is 2.3 mm.

Performance of a bunch width control system for coherent radiation with a high-current linear accelerator

A bunch width control system installed in a beam transport line of the high current L-band linear accelerator at Osaka University has been tested to study the coherent radiation of millimeter and submillimeter wavelengths. A 270° bending magnet having a debunching factor of 9mm/% for a nominal energy of 30 MeV was applied. Longitudinal distributions of electrons in the high-current single bunch have been analyzed by the observation of Cherenkov radiation using a streak camera. For a single bunch of a high-quality 30 nC beam having a natural bunch width of (35±3) ps in FWHM, possibility of a changing range 20–90 ps is proved with the 270° bending magnet and a quadrupoles lens system.

Width Control System for Hot Strip Mills Based on Multivariable Control

To attain a successful width control for hot strip mill, it is important to control a width at each stand preventing excessive tension imbalance for some specified stands.Our research goal is to develop a multivariable control algorithm for the new width control system. In the proposed algorithm, the width is controlled by modifying the inter-stands tension, which value is derived from the measured width and the on-line calculated width. An optimal control principle is applied and the tension balance can be maintained by tuning the weighting matrix in the performance index. The on-line control algorithm is designed such that the tension modification value can be obtained in short time, compared with the optimal regulator. This calculation is realized using a formula manipulating procedure and the control performance is same to that by the optimal regulator.The control system based on this algorithm has been applied to the hot strip mill and the width deviation can be remarkably reduced than before.