液压缸低速运动的动态分析

通过理论分析和试验验证研究了液压缸运动的非线性动态特征。提出弹簧刚度随活塞位移变化和工作状态不同而呈现出软硬弹簧特性的非线性弹簧力特征，其作用效果可以用有阻尼的Duffing方程来近似描述；摩擦力随速度的变化遵循Streibeck曲线，其作用效果随工作点在曲线上所处区段而异，可以用van der Pol方程来近似描述。指出液压缸低速爬行是在特定工况下的“跳跃现象”、自激振动等多重作用的结果。

Dynamic Analysis on Slowly Moving Hydraulic Cylinder

By means of theoretical analysis and experimental verification, nonlinear dynamic characteristics of moving hydraulic cylinder were discussed. The nonlinear characteristics of spring that spring stiffness varies with displacement of piston and the spring possessed soft or hard property with different states. The nonlinear characteristics of frictional force which varied with velocity of the piston and following the Streibeck curve and its effect varied with the working point within different section of the curve were exhibited. The conclusions are drawn, that the effect of nonlinear spring can be described by Duffing equation and the effect of nonlinear frictional force in lower velocity section can be described by van der Pol equation approximately. The reasons why hydraulic cylinder creeps in lower velocity are described, that is the combined result caused by many factors in specific working state such as jump phenomenon, self-excited vibration, etc.