系统参数对自激振动系统动力学稳定性的影响

为了研究机床进给系统的黏滑运动特性,建立了基于Stribeck摩擦模型的具有代表性的质体-弹簧-传送带摩擦自激振动模型.利用李雅普诺夫稳定性判据对自激振动系统的平衡点进行了稳定性分析,获得了系统的临界失稳速度,又经过理论公式推导出了系统的临界黏滑速度.从数值仿真得到的相图和Poincare截面图可以看出,随着系统进给速度、阻尼和传动刚度的增大,动、静摩擦差值的减小,系统的黏滞运动持续时间变短,即系统的稳定性增强;低速状态下的自激振动分为黏滑和纯滑动两个阶段,且均为准周期运动;系统进给速度是影响系统稳定性的主要参数.

Impact of the System Parameters on Self-excited Vibration System Dynamic Stability

The friction self-excited vibration system model with the plastid-spring-conveyor belt based on the Stribeck friction model was built to study the stick-slip kinetic characteristics of machine feed system. The stability of equilibrium point of self-excited vibration system was analyzed through the Lyapunov stability criterion， and the critical instability speed of the system was obtained， and then the critical stick-slip speed of the system was deduced from the theoretical formula. The phase diagram and the Poincare section diagram through the numerical simulation show that with the increase of machine feed rate， damping and stiffness of transmission and with the decrease of dynamic-static friction difference， the duration of stick-slip will be shorter， and the stability of the system increased. The self-excited vibration with low speed condition is divided into stick-slip and pure sliding， and they are both periodic motion. The feed velocity is important for the stability of the system.