PDF《热带钢轧机自动平坦度控制模型开发 钟恬 北京科技大学》

1 - 北京科技大学硕士学位论文 -

2 - Development of the Automatic Flatness Control Model for Hot Strip Mills Abstract Flatness is one of main targets of strip shape quality evaluation. Flatness quality is an important factor for the market competition. In order to ensure the flatness quality of the whole length of strip in hot rolling, automatic flatness control system is needed. There are many nonlinear factors concerned in hot continuous rolling and sometime with time-varying characteristics. So the flatness control system is a time-varying, strong coupling and complicated nonlinear system which is always a hot research area and difficult problem in control field. At present, the flatness control systems for hot strip mills in country were mainly imported from abroad, and then absorbed and improved. The research background of this dissertation is based on the key construction project of Angang in tenth-five year plan period, Angang 2150ASP hot strip rolling line construction. Based on design requirement, flatness closed loop control system is designed and improved through theory analysis and site investigation. Application of advanced algorithm and time-delay solution of the automatic flatness control system was researched. The main research contents and achievements are as follows: (1) The prediction models for flatness of hot rolled strip based on the BP neural network and RBF neural network were established. Simulation results show that the forecast models have high accuracy. (2) Fuzzy PID flatness control system model was established. The factors influencing the dynamic characteristics of fuzzy PID controller were analyzed by means of simulation. The fuzzy PID controller has better dynamic characteristics than the normal PID controller. (3) Smith predictive control methods were improeved to solve problems of time-delay in flatness control systems. Based on fuzzy control theory, the improved fuzzy PID-Smith predictive control algorithm, with the advantages of simple and high accuracy, was used in the flatness control model. (4) The automatic flatness control system of ultra-wide hot rolled strip was set up and successfully used in Angang 2150ASP production line after designing, programming and trouble-shooting. Product data show that this system is suitable for every kind of strip and can significantly improve the flatness quality of rolled strip. 北京科技大学硕士学位论文 Key Words:Hot strip mills, Flatness control, Neural network, Fuzzy control, Smith predictive control -

3 - 北京科技大学硕士学位论文 -

1 - 目录摘要.1 Abstract.2 引言.1

1 板形及板形控制.3 1.1 板形的基本概念.3 1.1.1 横截面外形.3 1.1.2 平坦度.5 1.1.3 凸度与平坦度的转化.6 1.1.4 板形良好判据

6 1.1.5 平坦度调控策略.10 1.2 带钢热连轧板形控制技术概况.12 1.3 智能控制在带钢板形控制中的应用.16 1.4 课题研究的内容及意义.16 1.5 本章小结

17 2 智能控制在带钢平坦度控制中的应用.18 2.1 神经网络在带钢平坦度预报中的应用.18 2.1.1 BP神经网络.18 2.1.2 RBF神经网络.20 2.1.3 带钢热连轧平坦度预报模型的建立.24 2.1.4 带钢热连轧平坦度预报仿真.26 2.2 模糊控制系统.28 2.3 模糊数学基本理论.29 2.3.1 模糊集合.29 2.3.2 模糊关系.29 2.3.3 模糊推理.30 北京科技大学硕士学位论文 -

2 - 2.4 模糊PID平坦度控制系统的设计与仿真研究.30 2.4.1 典型PID控制原理.30 2.4.2 模糊PID平坦度控制系统模型.32 2.4.3 模糊控制器设计方法.33 2.4.4 模糊PID平坦度控制器的设计.38 2.4.5 模糊PID平坦度控制系统仿真分析.40 2.5 本章小结