轧机自激振动诊断和结构动力学修改

SELF-EXCITED VIBRATION DIAGNOSIS OF THE ROLLING MILLS AND STRUCTURE DYNAMICS MODIFICATION

轧机是计算机控制的复杂机电系统。由于设计问题、结构损伤或系统故障,在某种条件或干扰下,可能产生持续自激振动。轧机的这种运行故障严重影响产品质量,损坏设备,甚至使生产中断。提出一种基于多参数同步综合测试、系统辨识和动力学分析与修改的综合方法,从试验与理论上分析了轧机产生自激振动的原因与消除方法。在研究的工程实例中,由辊缝位移传感器安装结构的动力学特性造成辊缝位移信号的响应延迟,引发板厚液压控制系统(AGC)非线性自激振动,从而产生整机持续的剧烈强迫振动。通过结构动力学修改,最大限度地减小位移反馈信号的延迟时间,大幅度地提高了系统的闭环稳定性,消除了正常工作条件(或正常扰动)下的自激振动,从而保证了轧机高效、稳定地工作。

The rolling mill is the complex mechano-electronic system controlled by computer. Improper design and some other factors may result in continuous self-excited vibration. The running faults of rolling mill influence badly product quality. Even production is interrupted. A method of self-excited vibration analysis based on multi-pa- rameter integrative testing and system identification is provided. The essential factors of the self-excited vibration phenomenon are analyzed by means of experiment and theory methods. The method of eliminating self-excited vibration is discussed too. In different operation conditions there are pure time lag in mathematic model of mill hydraulic AGC. When time lag exceeds a limit, self-excited vibration can occurs. The time lag may cause due to improper design of the mounted structures for roller gap displace transducer. Through dynamics modification, the time lag of displace feedback signal is reduced to minimum in the engineering case. And self-excited vibration is eliminated.