Mathematical Modeling And Simulation Of Strip Shape And Gauge Controlling In 1420 Cold Tandem Mills

Thickness and shape are important dicators that describe geometric accuracy of coldcontinuous rolling strip. In rolling process of strip, cold tandem rolling synthetical controlsystem composed of thickness control system, shape control system and tension controlsystem is a nonlinear, strong-coupling and involved multi-variable control system, and thecoupling relationships with each other restrait severely further improvement of stripproduction quality, consequently, realization of cold tandem rolling synthetical controlsystem decoupling control is a burning question. By traditional control theory, thicknesscontrol, shape control and tension control are taken as independent system withoutcorrelation of each other. They focuse on theory research of intelligent meathod andapplication on independent system, lacking knowledge of cold tandem rolling syntheticalcontrol system decoupling control application as well as correlative theory direction, and itbecomes the bottle-neck of application of decoupling control in old tandem rollingsynthetical system. In view of large rolling mill, proceed from coupling mechanism ofthickness control system, shape control system and tension control system, dynamicsimulation models of them are built with knowledges ofrolling theory, control theory anddecoupling control eta. Simultaneity, the coupling relationships are analysed andresearched, correlative coupling models are built and then dynamic decoupling controlstrategies are designed which make the cold tandem rolling synthetical system decouplingcontrol realized from technology setting and dynamic technology quality control. Thecontrol accuracy of cold tandem rolling strip is increased and production quality offinished strip is improved. Concrete work and the innovations in the dissertation asbellow:(1)Combined chaotic movement and self-adaptive adjusting inertia weight, anadaptive chaotic pso algorithm is proposed in the paper which is used to identifyparameters of hydraulic pressing system, so its efficiency is proved and it provides a newmethod for hydraulic AGC system identification based on on-the-spot data. And then thealgorithm is used to optimize neural net force prediction model which can further improve setting accuracy of rolling process parameters. According to analysis of process controlsystem in cold tandem rolling mills, dynamic simulation models of automatic gaugecontrol (AGC) system, automatic bending force control (AFC) system and automatictension control (ATC) system in cold tandem rolling process are established based on theirmechanism models, and the simulation results of every control systems are analyzed. Thesimulation results prove that it has good performance; therefor it provides a good platformfor the practical application, and build basis for decoupling control of the cold tandemrolling synthetical system too.(2)Setting calculation in cold tandem rolling control process of strip is analyzed andcoupling influence relationship of thickness setting as well as shape setting in settingprocess is gained. According to design decoupling compensation strategy of settingcalculation based on position inner loop and force inner loop, the coupling relationship iscompensated which can ensure setting calculation accuracy of inner loop actuator. In viewof deviation between rolling force prediction setting value and measured value, adaptivedecoupling control method when the strip is through cold mill is adopted to increaseimprecision of rolling force prediction and the necessary of setting decoupling isverificated according to living example.(3)The coupling model between thickness and tension is established, and thedecoupling model is designed. Considering the influence of incoming interference,implementation anti-interference decoupling control of coupling system between thicknessand tension is realized based on compensating strategy. Thickness and shape couplingmodels with two working methods of position and pressure inner loop are established tocompletely and systematically describe coupling relationship between gauge and shape ofcold tandem rolling system. Then, taking into account the incoming interference oncoupling system influences, decoupling strategy is designed for coupling system accordingto decoupling theory whick can realize completely anti-interference decoupling design ofgauge and shape coupling system. Finally, on the basis of decoupling of gauge and shapecoupling system, decoupling control stragety of crown and flatness is realized underdifferent control strategies.(4)According to increment mathematical equation, coupling model of cold tandem rolling synthetical system which can describe coupling relationship among the shapecontrol system, thickness control system and tension control system is established. Thenaccording to the characteristics of synthetical coupling model, the inverse system theory isused to realize linearization decoupling of cold tandem rolling synthetical coupling model.Finally, fuzzy immune PID controller is designed and improved to closed loop control thedecoupled system which can increases control precision of thickness and shape, andimprove the quality of thickness and shape.