Automatic Width Control Research Articles

Statistical, Spatial and Temporal Mapping of 911 Emergencies in Ecuador

A public safety answering point (PSAP) receives alerts and attends to emergencies that occur in its responsibility area. The analysis of the events related to a PSAP can give us relevant information in order to manage them and to improve the performance of the first response institutions (FRIs) associated to every PSAP. However, current emergency systems are growing dramatically in terms of information heterogeneity and the volume of attended requests. In this work, we propose a system for statistical, spatial, and temporal analysis of incidences registered in a PSAP by using simple, yet robust and compact, event representations. The selected and designed temporal analysis tools include seasonal representations and nonparametric confidence intervals (CIs), which dissociate the main seasonal components and the transients. The spatial analysis tools include a straightforward event location over Google Maps and the detection of heat zones by means of bidimensional geographic Parzen windows with automatic width control in terms of the scales and the number of events in the region of interest. Finally, statistical representations are used for jointly analyzing temporal and spatial data in terms of the “time–space slices”. We analyzed the total number of emergencies that were attended during 2014 by seven FRIs articulated in a PSAP at the Ecuadorian 911 Integrated Security Service. Characteristic weekly patterns were observed in institutions such as the police, health, and transit services, whereas annual patterns were observed in firefighter events. Spatial and spatiotemporal analysis showed some expected patterns together with nontrivial differences among different services, to be taken into account for resource management. The proposed analysis allows for a flexible analysis by combining statistical, spatial and temporal information, and it provides 911 service managers with useful and operative information.

Model‐Based Optimization of Short Stroke Control in Roughing Mills

Automatic width control is one key issue in hot strip rolling and the main actuator for width control is the vertical draft (edging) applied to slabs in the roughing sequence. In order to compensate for the occurring strip necking, a variable edger gap is applied in the edging process. This paper introduces a comprehensive mathematical optimization approach for the fully automatic generation of the associated edger roll trajectories, which is based on a nonlinear dynamic simulation model for the material flow in the roughing mill. Due to the complexity of this simulation model, gradient‐based methods are applied to solve the resulting optimization problem in reasonable time. Hence, derivatives of cost functional and constraints must be provided, which entails computing sensitivity information from the underlying simulation model. Finally, numerical results for real‐world examples are discussed to illustrate the capability of the presented approach. In particular, this paper examines the influence of characteristic parameters such as the slab width or the maximum edger screw in velocity onto the optimization results.

The calculation of vertical rolling force by using angular bisector yield criterion and Pavlov principle

The automatic width control of the strip that is used in vertical rolling is a key issue in the hot strip rolling process. It is the first time that the internal deformation power and the friction power are obtained by using angular bisector yield criterion and Pavlov projection principle in the vertical rolling. At the same time, the shear power is determined by use of the integral mean value theorem. Then the vertical rolling force and shape parameters are obtained by minimizing the total power functional. The relative error of rolling forces is less than 8.29 % compared with those measured on-line in a hot strip rolling plant. Moreover, the formula forms of the three powers mentioned above are greatly simplified and improved.

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.

Automatic Width Control for Hot Strip Mills based on Hybrid System Model

Automatic Width Control for Hot Strip Mills based on Hybrid System Model

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.

A Spatial Kinetics Method Ensuring Neutronic Balance with Thermal-Hydraulic Feedback and Its Application to a Main Steam Line Break

The rate equation for neutronic population is derived from the transient neutron diffusion equation. Neutronic imbalance is defined as the difference between the solution of the rate equation and the neutronic population obtained by spatial kinetics. If the transient neutron diffusion equation in the fully implicit formulation is discretized in such a manner as to satisfy the Gauss theorem and to retain a conservation form, neutronic imbalance decreases as the convergence criteria become strict. The iterative implicit method for neutronics and thermal hydraulics requires continuity of all the variables involved, which, in turn, facilitates the automatic time-step width control. From the viewpoints not only of well-posedness of a transient problem but also of code verification, a transient code should be capable of a null transient analysis for stable systems. Sample calculations are performed for a pressurized water reactor main-steam-line–break accident. An overall thermal-hydraulic trend model is conjectured to help compare and explain the calculated results. Spatial kinetics is found to clearly influence even the temporal behaviors of the secondary system.

Optimal control system for hot strip finishing mill

This paper describes how to control the strip gauge, looper angle, and strip tension for a hot strip finishing mill, and gives the results of a real application. This is based on optimal servo theory and the model decoupling method. In the finishing mill process, there exists a mutual interaction among the strip gauge, the looper angle, and the strip tension. Conventionally, each of them is controlled independently. To improve the control performance, multivariable control that considers this interaction is applied to the whole productions process. The new control system is also used for the tension control of the automatic width control.

Optimal Control System for Hot Strip Finishing Mill

This paper describes how to control strip gauge, looper angle, and strip tension for a hot strip finishing mill and the application result. This is based on the optimal servo theory and the model dccoupling method. In finishing mill process, there exists mutual interaction among strip gauge, Iooper angle, and strip tension. Conventionally, each of them is controlled independently. To improve the control perfonnance, the multivariable control considering this interaction is applied to all productions. The new control system is also used for the tension control of the automatic width control.

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.

Development of high-precision shape and crown control technology for strip rolling

The dimensional accuracy of hot-rolled coils, a product type which sees a wide range of use at the present time, has reached a general high level of technical accomplishment by the application of various techniques, such as automatic longitudinal gauge control, automatic width control, and shape and crown control. The subject of shape and crown control - which itself is a most sophisticated high technology - with its technical background is discussed as the main theme in this paper and the features of various types of equipment as the means of control are described. Although the high crown control mill (HC mill) and the pair cross mill (PCM) have a high capability of shape and crown control, the characteristics of other types of mill are described also so that the selection of technology can be made as necessary for each particular mill.

Development of width control system in hot strip mill. Performance test result on actual AWC edger.

Width control in hot strip mill includes sizing of a continuous cast slab, decreasing the fish tail crop loss in the head and tail ends of rough bar, minimizing the width deviation or automatic width control (AWC). These have been studied in order to increase the material yield as well as to improve the strip width accuracy. The authors have developed an automatic width control system, which consists of a width-gauge feed-forward control and learning control to improve the width accuracy at the roughing mill delivery side by adjusting the roll opening of the hydraulic AWC edger. This paper covers the general description of the mathematical model of width deformation, the characteristics of the control system and the excellent capability of this system, confirmed by an actual edging operation in a hot strip mill.

Hot Strip Width Control by Computer

This paper deals with the automatic width control system of a senicontinuous hot strip mill, which was entirely developed and implemented by ITALOIDER personnel in the Oscar Sitiigcigliu Works.The paper describes the following:-the mathematical identification of the process parameters;-the off-line model for the rolling presets calculation;-the on-line multilevel system for strip width driving.In particular, the physical phenomena involved, the experimental procedures and the statistical methods which concern the identification are presented.The optimization strategy of the off-line model is discussed in detail, and an application is given. The levels of the on-line system are described, that is: the optimization function, which is structured in two hierachically coordinated sublevels, and the direct control function.Practical results are given and discussed.

Equipement Electronique De Reglage D'Une Calandre Pour Tissu Caoutchoute

Summary This memorandum shows the application of variable speed control units to plurimotors rubber calanders. In particular the memorandum outlines the following features: A) Speed control units for cylinder rotation with automatic speed control and synchronisation of cylinder motion. B) Automatic width control of rubber calanders. C) Automatic control of the driving motors pre and post calanders. The same kind of speed control units can be used for calanders in the plastic and similar industries.