【摘要】 往复运动中的摩擦力信号往往是非平稳信号,采用经验模式分解法可以自适应地分解这些非线性、非平稳信号,合理地提取其信号特征。应用希尔伯特-黄变换方法,分析不同往复速度和载荷条件下往复运动产生的摩擦力信号,并提取时频段能量比及其标准差,研究其润滑状态特征。结果表明:通过希尔伯特-黄变换并结合能量比分析,可以很好地反映出往复运动过程中润滑状态的变化;在一定载荷下,随着往复速度的增加,摩擦力频率成分趋于平稳,能量比标准差则逐渐减小;在一定往复速度下,随着载荷的增加,润滑状态变差,消耗的能量随之增大,能量比标准差逐渐减小;和往复速度相比,载荷对摩擦力频率分布影响相对较小。更多还原

【Abstract】 Reciprocating force signal is usually non-stationary. The empirical mode decomposition( EMD) method can decompose these nonlinear and non-stationary signals adaptively,and extract the signal characteristics reasonably. The force signals of reciprocating movement under different speed and load conditions were analyzed by applying Hilbert-Huang transform( HHT) method,the energy ratio of time-frequency band and its standard deviation was extracted to study the lubrication state characteristics of reciprocating movement. The result shows that HHT combined with the energy ratio analysis is a very good way to reflect the variation of lubrication condition in the process of reciprocating movement. Under certain load condition,the friction frequency is tended to be stabilized,and the standard deviation of energy ratio is decreased with increasing of reciprocating speed. At a certain reciprocating speed condition,the lubrication state is gotten worse,and the consumption of energy is increased,but the standard deviation of energy ratios is decreased gradually along with increasing of the loads. As compared with reciprocating speed,the load has smaller effect on friction frequency distribution.更多还原