铝板带材冷轧机板形板厚解耦控制策略的研究

【作者】 杨甫勇；

【导师】 桂卫华；

【作者基本信息】 中南大学 ， 控制科学与工程， 2009， 硕士

【摘要】 板形与板厚是决定铝板带材几何尺寸精度最为重要的两大质量指标,厚度自动控系统(AGC)是为了保证铝板带材纵向厚度的精度,板形自动控制系统(AFC)是为了获取铝板带材横向厚度的均匀性和良好的平直度。经过几十年的发展,板形控制和板厚控制已经达到了较高的控制精度。然而板形板厚控制(AFC-AGC)系统实际上是一个耦合的复杂多变量控制系统,在铝板带材冷轧生产过程中,板厚控制和板形控制本质上都是对轧制过程中有载辊缝的控制,两者存在很强的耦合关系,实现板形板厚的解耦控制己经成为一个进一步提高控制精度急待解决的难题。板形板厚的耦合作用更多地表现为一个实时、动态作用过程,为此从AFC-AGC系统的耦合机理出发,系统深入地研究了系统的动态耦合模型及相应的动态解耦控制策略,并结合仿真试验结果,在生产轧制实践中验证了上述理论研究的正确性,提高了铝板带材轧制生产质量。主要研究内容如下所述:研究将板形控制和板厚控制系统作为一个整体来考虑,建立了AFC-AGC动态数学模型。针对AFC-AGC系统动态数学模型,应用不变性原理并结合PID控制算法对AFC-AGC系统进行了解耦控制,应用Smith预估器对纯滞后环节进行处理,仿真结果表明解耦控制效果良好,减小了板形板厚控制的耦合影响;当系统在运行过程中模型参数发生变化时,解耦控制性能会变差,基于模型参考自适应控制和解耦控制理论,提出了多变量自适应解耦控制方法,有效解决了解耦过程中系统模型参数的不确定因素影响控制性能的问题,仿真结果表明该控制策略提高了解耦控制精度;由于设定控制是AFC-AGC系统动态控制的起点,影响系统动态控制效果,为此,建立了基于设定控制的静态耦合模型,提出了板形板厚设定补偿解耦控制方法,形成了比较完整的板形板厚解耦控制策略。上述研究成果对于板带材轧制生产过程具有一定的普遍意义,对板形板厚解耦控制理论的实际应用有很好的参考价值。更多还原

【Abstract】 As we know, strip flatness and gauge geometry dimension accuracy are the most important factors of product quality. The Automatic Gauge Control (AGC) system can guarantee the precision of the vertical thickness of aluminous board and strip and the Automatic Flatness Control (AFC) system can guarantee the precision of the horizontal thickness of aluminous board and strip. With the development of past few decades, both AFC and AGC can be obtained rather degree of control accuracy. However the Flatness and Gauge Control (AFC-AGC) system is a coupled complex multivariable control system, Gauge control and Flatness control are both master of the aperture of cold mill during the process of aluminous timber rolling, and intense coupling connection exists in both of their control loops, it is an active demand to solve the problem to improve control precision ulteriorly.The cross coupling process between AFC and AGC is real-time and dynamic, on the basis of deformation mechanism of AFC-AGC system, a dynamic coupling model and the corresponding dynamic decoupling control strategy are built, the decoupling methods applied to the production mill have been proved to be effective with the simulation experiments result. The main study content is described as follows:The strip rolling process is analyzed by the method that considers the AFC and AGC as a whole process in the research, and the dynamic mathematics model is proposed. The decoupling control based on the invariability principle and the PID control arithmetic is implemented when getting the dynamic mathematics model of the AFC-AGC system, and the dead-time tache is disposed with Smith-predictor at the same time, the decoupling control effect is proved by the simulation result, and the coupling influence of flatness and gauge control is decreased. The decoupling control performance will break up while the model parameters of the system change in the process of running. According to self-adaptive control of model reference and decoupling theory, the multivariable self-adaptive decoupling control method which solves the uncertain factor of system model parameters that affect the problem of control performance in the decoupling process is put forward, and the simulation result indicates the control precision is improved with this control strategy. As the setting control is the start point of dynamic control of AFC-AGC system, and the effect of dynamic control of the system will be influenced by it, therefore the static coupling model based on setup control is constructed, and the compensatory decoupling method in flatness and gauge setup programs is put forward, which makes decoupling control strategy of AFC-AGC system more integrity.The obtained harvest is general for the production process of board and strip, and it provides a good reference for the application of decoupling control theory of AFC-AGC system.更多还原