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Optimization of Force and Power Imposed on Continuous Tandem Cold Rolling Rollers Using a Multiple-Function Genetic Algorithm
Mehdi Safari, Mohammadreza Moghoomi
Open Access Library Journal (OALib Journal) , 2015, DOI: 10.4236/oalib.1101401
Abstract: The amount of energy consumed in the production lines such as cold rolled process is one of the fundamental problems in the energy infrastructure of manufacturing sectors. Accordingly, much attention should be directed towards optimizing the power consumption of production lines using reasonable methods. Furthermore, the powers exerted on such equipment must be modified to find an optimized energy consumption level. This study tries to examine the optimization of forces and powers imposed on the continuous tandem cold rolling rollers of metal sheets using MATLAB and genetic algorithm. Firstly, some relationships and calculations of rolled metal sheets are analyzed. Then parameters, such as percentage of thickness reduction, mean pressure, yield stress, power of rollers and exerted torque, are calculated. All the governing relationships are programmed using MATLAB software. Having compared the mentioned two methods, genetic algorithm is used to determine the optimal required power. The results show that the optimized powers generated by genetic algorithm method are in good agreement with experimental observations. Also, the powers of rolling rollers and standard deviations of powers are calculated and, then, the two functions are compared and the optimum point between them is optimized.
Hybrid Intelligent Modeling Approach for Dynamic Cold Tandem Rolling Process

Tie Ming,Chai Tian-You,Yue Heng,Zhang Zhen-Shan,Zheng Xiu-Ping,

自动化学报 , 2007,
Abstract: This paper presents a hybrid intelligent model for multi-stand cold tandem rolling dynamic process, a system with compositive complexity including nonlinearity, multi variable, strong coupling, varying parameter as operation condition vari-ation. The proposed model consists of the based state-space model based on linearized physical equations near rolling oper-ating points, the exit strip speed RBF models and estimation approach for time lag of entry thickness, case-based reasoning technique based multi models selection algorithm for di?erent operating points. With the actual thickness system setting and plate disturbance, the simulation results of roll force, strip thick-ness and tension have the same dynamic characteristics with the actual process data, and the error of each variable is less than 20%.
Improved adaptive weight approach GA based rolling schedules multi-objective optimization of tandem cold rolling

LI Yong,LIU Jian-chang,WANG Yu,

控制理论与应用 , 2009,
Abstract: To select correct weighting factors for the weight-sum multi-objective method, we propose an improved adaptive weight-selection approach. On the basis of the genetic algorithm(GA), this approach is applied to optimize the multi-objective rolling schedules in a tandem cold rolling. In the optimization process of rolling schedules, the power distribution, the rolling energy consumption and the slip rate are selected as objective functions from them the multiobjective model of rolling schedules is established. Applying the improved adaptive weight approach GA to optimize rolling schedules for strips with different specifications, we reduce the values of the above three objective functions simultaneously, in comparison with the conventional rolling schedules. It also provides better pertinence and faster convergence for objects of higher priority than those of the adaptive weight approach GA.
Models and Algorithms of Production Scheduling in Tandem Cold Rolling

ZHAO Jun,LIU Quan-Li,WANG Wei,

自动化学报 , 2008,
Abstract: The complexity of production scheduling problem in cold rolling line is analyzed,which is formulated as two parts, namely,the coil-merging optimization and the rolling batch planning.The optimization of steel coil merging is constructed as a multiple container packing problem(MCPP)that is computed by a new proposed algorithm,discrete differential evolution(DDE), in this paper.A specific double traveling salesman problem(DTSP)is modeled for the rolling batch planning,and a hybrid heuristic method on the basis of evolutionary mechanism and local search is presented to solve this model.The experimental results with real production data from Shanghai Baosteel Co.Ltd.show that the production scheduling method suggested in this paper is effective.
Multivariable decoupling robust control for the thickness and tension system of tandem cold rolling mill

LI Zhong-de,YANG Wei-dong,

控制理论与应用 , 2011,
Abstract: Based on the invariance-decoupling theory, a new robust control scheme using H-in nity mixed sensitivity is introduced for thickness and tension system with the features of multivarivble, strong coupling and uncertainty in tandem cold rolling process. The thickness and tension dynamic coupling model is built, and the invariance-decoupling theory is used to decouple the MIMO system to weaken the coupling effects. Then a robust controller is designed using H-in nity mixed sensitivity method for system uncertainty of dynamic model parameter perturbation and external disturbance to insure the robust stability and robust performance. Simulation results show the effectiveness of the algorithm for the thickness and tension system.
Vertical Vibration Model for Unsteady Lubrication in Rolls-Strip Interface of Cold Rolling Mills  [PDF]
Xu Yang,Qing Li,Chao-nan Tong,Qi-han Liu
Advances in Mechanical Engineering , 2012, DOI: 10.1155/2012/734510
Abstract: According to the vertical vibration phenomena existing in cold rolling mills, the unsteady lubrication mechanism in roll gap and its influence to rolling stability was chosen as the case for analysis. On the basis of rolling theory, lubrication and friction theory, and mechanic vibration theory, the vertical vibration model for unsteady lubrication in rolls-strip interface was presented. The Geometry model of roll gap, the unsteady lubrication model of roller-strip working interface, the distribution model of normal rolling stress and friction stress, and the rolling vertical structure model were taken into account. Based on the rolling equipment and process parameters of aluminium mill, the rolling force curve and dynamic response of working roll displacement variation was simulated on Matlab/Simulink platform. A comparison with actual production data shows the validity of this vibration model. 1. Introduction The cold rolling process is a high speed, transient, and time-related metal machining molding process [1]. As cold rolling mill is a multimass and rotary motion object system, the vibration as an implicit factor commonly exists in the course of its operation, but it usually does not apparently present due to the conditional constraints of factors such as various rolling processes, equipment, and control. In fact, once the mill running state exceeds the accuracy requirements of the product or equipment bearing capacity, mill vibration phenomena will emerge. Of torsional vibration, vertical vibration, and vertical torsion-coupled vibration of transmission system in the rolling process [2], the third-octave vibration of vertical system causes the greatest harm [3, 4], which will have adverse effects on quality indicators of rolled product in thickness and shape and even cause a great deal of production loss such as serious equipment damage. Therefore, the modeling, analysis, and control for cold rolling mill with vibration factors have been the focus of research domestically and abroad all the time [5, 6], and also a number of meaningful research results have appeared [7, 8]. The rolling process is the process of roll contacting strip with each other, and the frictional force is the tangential resistance in the interface between these two objects. As we can see from [9, 10], the unstable lubrication state of two degrees of freedom can lead to a stick-slip phenomenon and therefore cause self-excited vibration. In order to reduce the adverse effects caused by the outer friction, it is essential to have the industrial lubricant mechanism in roll gap
Role of Friction in Cold Ring Rolling
He YANG,Lianggang GUO,Mei ZHAN,
,Lianggang GUO and Mei ZHAN College of Materials Science and Engineering,Northwestern Polytechnical University,Xi''''an,China

材料科学技术学报 , 2005,
Abstract: Cold ring rolling is an advanced but complex metal forming process under coupled effects with multi-factors, such as geometry sizes of rolls and ring blank, material, forming process parameters and friction, etc. Among these factors,friction between rolls and ring blank plays animportant role in keeping the stable forming of cold ring rolling. An analytical method was firstly presented for proximately determining the critical friction coefficient of stable forming and then a method was proposed to determine thecritical friction coefficient by combining analytical method with numerical simulation. And the influence of friction coefficient on the quality of end-plane and side spread of ring,rolling force, rolling moment and metal flow characteristic in the cold ring rolling process have been explored using the three dimensional (3D) numerical simulation based on the elastic-plastic dynamic finite element method (FEM)under the ABAQUS software environment, and the results show that increasing the friction on the contact surfaces between rolls and ring blank is useful not only for improving the stability of cold ring rolling but also for improving the geometry and dimension precision of deformed ring.
The Heat Conditions of the Cold Pilger Rolling  [PDF]
Frolov, Ya. V.,Mamuzi?, I.,Danchenko, V. N.
Metalurgija , 2006,
Abstract: The influence of technological factors and constructive parameters of the cold pilger rolling mill to the warm conditions of deformation is observed. The dependences of the heat conditions of pilger rolling on deformation mode and preheating temperature are shown. There was a conclusion drawn about the expediency of combination of warming and cooling of the metal for keeping the deformation zone temperature within limit, which corresponds to the minimal intensity of the metal strengthening.
Robust Tension Control of Strip for 5-Stand Tandem Cold Mills  [PDF]
Behrooz Shafiei,Mohsen Ekramian,Khoshnam Shojaei
Journal of Engineering , 2014, DOI: 10.1155/2014/409014
Abstract: Tandem cold rolling process is a nonlinear complex system with external and internal uncertainties and significant disturbances. The improvement in the quality of the final output depends on the control strategy of centerline thickness and interstand tension. This paper focuses on interstand tension control problem in 5-stand tandem cold rolling mills. Tension dynamics can be described by a nominal model perturbed by parametric uncertainties. In order to overcome the model uncertainties and external disturbances, suboptimal and controllers are proposed and the Hankel-norm approximation is used to reduce the order of controller. The performance of the proposed controllers is demonstrated by some simulations. 1. Introduction The production of cold rolled coils typically consists of separate processes such as annealing, pickling, cold rolling, and skin pass rolling. The cold rolling of strip is one of the most important processes in the areas of manufacturing and processing of metals. Tandem cold mill (TCM) is one type of cold rolling processes that strip thickness reduction is achieved with a number of nonreversing stands. The production of this process can be applied for various industries such as food packaging, automobile manufacturing, and home appliance [1, 2]. Thus, the improvement and development of new technologies of rolling have become important for researchers, engineers, and manufacturers. Tension control is one of the most important process parameters in tandem cold mill (TCM). Changing roll velocity stabilizes the interstand tension [3]. Interstand tension should be maintained at acceptable levels. Large transient variations in tension may result in a dramatic and physically damaging failure of the mill through looping, where the strip tension falls to zero, or tearing of the strip [4, 5]. Various advanced methods have been developed to analyze and control rolling mills [6–11]. Among the previous investigations, some notes focus on tension control problem in cold rolling mills [12, 13]. There are numerous uncertainties and disturbances in the model of tandem cold rolling process [14]. Thus, the control strategy for cold rolling should be robust with respect to the uncertainties and disturbances. Linear quadratic control strategy () guarantees the optimality but it has weakness in the presence of uncertainties. The suboptimal method and synthesis/analysis method have been adopted as the robust techniques in many approaches and provide systematic design procedures of robust controllers for linear system [3, 15, 16]. To promote tension control
JX Li,XH Liu,GD Wang,

金属学报(英文版) , 2002,
Abstract: Two kinds of cold rolling experiments, single cold rolling and double cold rolling, were carried out on one titanium stabilized interstitial free (IF) steel that has been warm rolled at ferrite temperature. The main aim was to investigate the evolution of rolling and annealing textures from the well known behavior observed under single cold rolling condition to the less understood double cold rolling by using orientation distribution function (ODF). In the twice cold rolled samples, the annealing texture comprises only single {111}(110-112) r-fibre texture when it subjected to moderate reduction in the first round of rolling. Accordingly both the once cold rolled sample and the twice cold rolled sample with heavy reduction in the first round of rolling have much complex texture components. They are related to the formation of initial {111} subgrain and the priority growth of stable {111} nucleus.
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