转速随机波动旋转机械振动信号的周期平稳性

首先推导了旋转机械转速波动的随机角位移统计特性,证明了随机角位移信号是一种非平稳的随机过程.对于离散随机角位移序列,提高采样率可以减小其随机性.当采样率无限增加时,该序列将退化为确定性序列.然后以不平衡质量的惯性力为例,以转角和时间为参量,分别推导出一阶和二阶矩统计量.这些统计量证明,以转角为参量的惯性力随机矢量信号是非平稳的,但具有周期平稳性;而以时间为参量的惯性力随机矢量不仅是非平稳的,而且一般也不具有周期平稳性.

Cyclostationarity of vibration signal of rotating machine with random fluctuation of angularspeed

The statistical properties of random angle signal due to angular speed fluctuation of rotating machine are proposed.That the random angle signal is non-stationary is verified.For discrete angle series,the sampling rate increases,the randomness of the series can be reduced,and the discrete series will become definite when the sampling rate is infinite.For the inertia force vector due to unbalance mass and angular speed fluctuation,the first-order and second-order moments of statistical parameters of the random force vector are put forward.These moments indicate that the inertial force random vector based on angle-base is non-stationary,but cyclostationary and the vector based on time-base is not only non-stationary,but also not cyclostationary in general.