中文摘要：

高性能复杂整体模锻件的等温锻造要求大型模锻压机必须具备在极低速下稳定运行的能力,但巨大运动惯量、液压非线性与低速摩擦导致该装备在极低速运行时极易出现速度震荡,甚至产生爬行现象。针对这一问题,在考虑压机液压非线性与低速下特有的静-动交替变换的摩擦特性的基础上,建立大型模锻压机极低速下的非线性运动模型,并提出该模型的求解方法,获得系统的近似速度;通过对近似速度的分析,推导出极低速下压机3种工况条件：1）压机稳定运行的判断条件;2）压机速度震荡的判断条件以及速度震荡幅值计算公式;3）压机爬行的判断条件。最后通过仿真验证了这些规律的正确性,为控制大惯量装备极低速稳定运行提供理论基础与保证。

英文摘要：

Isothermal forging of high-performance complex overall die forging requires a large forging press to have the ability to operate stably at extremely low speed. However, at a very low speed, the press＇ s speed is extremely prone to shock and even creep because of the huge moving inertia, hydraulic nonlinear and friction. In view of this question,considering the hydraulic nonlinear and a static-dynamic alternating friction characteristics at the low speed, a nonlinear motion model of the press at extremely low speed was established. At the same time, a method to solve this model was proposed, and the approximate speed was then got. By analyzing the approximate speed, three working conditions were obtained： 1） large die forging＇s stable running condition; 2） speed shocking condition and the mathematical expression of speed shocking degree; 3） the creeping condition. At last, the correctness of these rules was verified by simulation, and all these rules provide a theoretical foundation and guarantee the control of large inertia equipment＇s stable operation at extremely low speed.