非线性影响下高速轧机机-电-液耦合系统振动机理与控制方法

The phenomenon of vibration in high-speed rolling process has been recognized as a major restriction to the improvement of strip quality and productivity of rolling mills. Because of its nonlinearity and strong coupling effect in the parameters among rolling mill sub-systems, it makes difficulty for a better understanding of the vibration mechanism and control strategy. Based on that, some original research works will be developed in this field. .By analyzing the vibration process of cold rolling mill, the coupling dynamic model, which couples with rolling process model, the mill stand structure model, the hydraulic servo system model and the control system model, is built with nonlinear effects. Numerical Simulation will verify the effectiveness and advancements of those models. Meanwhile,the influence to stability of rolling mill system by different working conditions will be discussed with industrial mill data, and the energy input mechanism of rolling self-excited vibration system is illustrated with some nonlinear analysis methods. In addition,in order to suppress instability oscillation of coupled rolling mill system caused by Hopf bifurcation, a nonlinear feedback controller is proposed to transfer bifurcation points of system, and the parameters of controller will be optimized. Simultaneously, with the consideration of strip quality, the strip thickness model with perturbation dispersion will be established in a simplified form after linearization process, and the robust controller based on u-synthesis/quantitative feedback theory(QFT) will be designed. A comparison with other controllers will show its better disturbance attenuation performance for parameter uncertainty and external disturbance. Besides, the real-time simulation platform will be estabilished for the analysis of performance in those control algorithms. The research work in this project will contribute the further study of vibration mechanism analysis and chatter suppression in rolling mill.

轧制过程中普遍存在的轧机振动现象会严重影响产品质量，降低生产效率，它已引起国内外的广泛关注。但轧机各子系统参数间的非线性、强耦合特性会对振动的分析与抑制带来困难。对此，本项目以四辊高速冷轧机为研究对象，探索机械、电气、液压及轧制工艺系统参数在动态条件下的耦合效应，推导非线性影响下高速轧机机-电-液耦合系统增量振动模型；利用现场数据和实验模型分析轧制工艺参数变化对系统稳定性的影响，运用非线性分析方法阐明自激振动系统的能量输入机制，揭示轧机耦合系统的振动机理；对模型受谐波参数激励引起的Hopf分岔现象，采用优化算法设计非线性反馈控制器参数，以避免亚临界分岔行为；根据轧机耦合系统中的分散不确定性，对经线性化处理后的板厚摄动分散系统传递函数模型，设计基于u综合/定量反馈理论的鲁棒控制器，并通过实时仿真平台对比控制算法性能。本项目的研究成果将为轧机振动机理分析与控制策略的研究提供有效方法和理论依据。

高速板带轧制过程中普遍存在的轧机振动现象会严重影响带钢的产品质量，降低生产效率，严重时会损害机械和电气设备，这已引起了国内外的广泛关注。但是，轧机各子系统参数间的非线性、强耦合特性会对振动的机理分析和抑制带来困难。本项目以钢铁流程中的带钢冷连轧生产过程为背景，以四辊高速冷轧机为研究对象，提出一套适合于轧机系统耦合建模、振动机理分析及控制的理论与方法。主要体现在以下四个方面：1）通过分析轧机机械、电气、液压及轧制工艺各子系统间的参数耦合效应，建立含非线性因素的高速轧机机电液耦合系统振动模型，并基于工业现场数据验证其有效性和先进性；2）对轧制过程的扭振和垂振现象，基于能量输入机制，采用奇异值理论、多尺度法及Hopf分岔理论等定量分析方法，分析不同轧制工艺参数对耦合系统稳定性的影响；3）对轧机主传动、液压等子系统由于轧制过程失稳/振动导致的产品质量下降，采用ADRC、微分几何方法、鲁棒QFT理论，进行相应子回路的控制器设计；4）通过分析复杂工况下由工艺参数波动导致的轧机垂直振动，采用EEMD算法和SVM理论，进行数据驱动的故障诊断技术研究，实现轧机振动相关故障的精确诊断。此外，项目组还对复杂动态轧制过程的关键性能指标监测、故障诊断与容错控制方面展开探索性研究，取得了一定的研究成果。在应用前景方面，上述研究成果将为板带轧制过程的安全稳定运行和产品质量改善提供有效的方法和理论依据。