针对自适应前馈控制方法的缺点，提出一种周期性振动主动控制的自适应反馈控制方法。
As the adaptive feedforward control method used for active control of periodic vibration has many shortcomings, an adaptive feedback control method was proposed based on on-line frequency estimation.
本文通过尾水管内流动的模拟，导出了由尾水涡带所引起的周期性振动的振动频率和脉动压力的计算公式。
This paper gives the flow simulation of hydraulic turbine draft tubes. Then, the calculation formula of the frequency and force of vibration of the draft tube are derived.
海浪是海面起伏形状的传播，是水质点离开平衡位置，作周期性振动，并向一定方向传播而形成的一种波动。
The waves of the sea is the shape of the spread, and is left at the water quality, balance position periodic vibration and spread to certain direction, in the form of a wave.
通过时域波形和频谱等基本分析手段来探测振动加速度信号中的周期性冲击分量往往是困难的。
It is difficult to detect the periodic impulse component in the vibration acceleration signal with conventional analysis methods such as time domain wave and frequency spectrum.
泵输出的周期性脉动流体的压力脉动，是引起流体谐振、激励管路振动和噪声的主要原因。
The pressure pulsation induced by the pumped periodic pulsation fluid is the main factor of causing fluid resonance and stimulating pipelines vibrations and noise.
机械设备振动信号中是否存在周期性的冲击分量是其有无故障的重要标志。
Whether there exists a periodic impulse component in a vibration signal is an important sign of a mechanical device being faulty.
张力腿平台的垂荡引起张力周期性变化，对张力腿的涡激横向振动起参数激励的作用，使其动力响应更为复杂。
Periodical variations of tether's tension caused by heaving oscillation of TLP play the role of a parametric exciter to vortex-induced vibration, and make it more complicated.
第一部分介绍飞行器实测振动数据的平稳性、周期性和正态性检验的几种方法；
The first deals with several i methods used to test stationarity, periodicity and guassianity of the recorded data of aircraft vibration.
该模型由描述系统振动的双曲型偏微分方程组及相应的边界条件和周期性条件组成。
This model consists the hyperbolic partial differential equations, boundary conditions and cyclical conditions of the system.
确定振动是由入口调节门后中心涡流引起的气流周期性高脉动造成的。
Vibration is caused by periodic high pulsation of airflow resulted from the center eddy behind the inlet damper.
通常检测的机械振动加速度信号，由于信噪比太低，即使存在周期性的冲击分量也往往被淹没在强的背景噪声之中。
However, in respect of a vibration acceleration signal, the signal to noise ratio (SNR) is often so small that the periodic impulse component is submersed in its intense background noises.
通过研究周期性负载机械系统振动信号的特点，构造了包括状态方程和观测方程的振动信号模型。
By studying the vibration signal characteristics in periodic loading machine system, vibration signal model including state equation and observed equation was constructed.
然后令计算网格随叶栅振动而振动。时间推进计算到流场参数随时间作周期性变化，振幅、相位稳定为止。
Time marching is continued until the calculated parameters vary with time periodically with stable amplitudes and phases of vibration.
在运动涡旋相，电压的轨迹相对时间是周期性的，其振动频率与电流密度成正比。
In the moving vortex lattice phase the time dependent voltage is periodic with time, and the frequency of voltage is proportional to the current density.
国内外在研究钻柱振动时都把钻柱下端当作铰支，假设激振源为周期性的，偏离实际。
At present, the end of drill string (DS) is simplified as a hinge in FE analysis and the excitation is assumed periodic.
在非正弦周期性外力作用下受迫振动的实验结果，并十分清楚地显示了受迫振动的较为完整的图像。
This paper mainly introduces and discusses the experimental results of the forced oscillation excited by a non-sinusoidal periodic driving force.
从二维周期性结构的振动方程出发，建立二维带隙计算模型，并在此基础上分析带隙与材料结构特性的关系。
By analyzing the vibration model of two-dimensional (2d), the elastic wave band gaps of 2d were calculated and the connection of the elastic wave band gaps with material characteristic was studied.
轴系装置由于不仅具有惯性而且具有弹性，因此在周期性荷载作用下，会产生扭转振动，甚至于产生拍振。
Under the periodical loads, the shaft must have the torsional vibration, named "beat", because the shafting has not only inertia but also elasticity.
轴系装置由于不仅具有惯性而且具有弹性，因此在周期性荷载作用下，会产生扭转振动，甚至于产生拍振。
Under the periodical loads, the shaft must have the torsional vibration, named "beat", because the shafting has not only inertia but also elasticity.
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