中文摘要：

针对液压系统动态特性影响下的轧机振动问题,建立一种液压缸非线性刚度约束下的轧机辊系振动模型,采用平均法求得系统的幅频响应。在Lyapunov第二方法的基础上,设计了系统的反馈控制器。以轧机实际参数为例,仿真分析轧机辊系中非线性刚度系数、外激励和无杆腔初始位移等参数对幅频响应的影响,并研究外激励幅值和无杆腔初始位移等参数发生变化时的动态分岔特性,发现随着这些参数的变化,轧机辊系振动在周期运动、倍周期运动和混沌运动等多种运动状态之间交替变化;同时在系统中引入反馈控制,通过对比控制前后的时域曲线和相平面曲线,验证了反馈控制器的有效性。研究结果为提高轧机辊系稳定性提供了理论参考。

英文摘要：

For the vibrations of rolling mill under the influences of dynamic characteristics of hydraulic system,a kind of vibration model of a roll system was established under the constraints of the nonlinear stiffness of hydraulic cylinder.Amplitude-frequency response of the vibration system was obtained by using average method,the feedback controller of the system was designed based on the Lyapunov second method.Lastly,parameters of the actual mill were used to conduct a simulation research and parameters such as nonlinear stiffness coefficient,external excitation and initial displacement of the rodless cavity were analyzed how did which to affect the amplitude-frequency response.The dynamic bifurcation characteristics of the excitation amplitude and the initial displacement of the rodless cavity were studied,results show that as the changes of the parameters,the rolling mill will cause periodic,period-doubling,chaotic motion and a series of complex movements.At the same time,the feedback control was introduced,and the effectiveness of the feedback controller was verified by comparing the time domain curves and the phase plane curves,which provides a theoretical basis to improve the stability of rolling mill rolls.