提高扭转振动信号分析精度的方法研究

在采用三点卷积幅值修正方法和比值校正法大幅度提高扭振稳态信号幅值分析精度的同时，针对发动机升降速过程中扭振时变信号存在低频滚振干扰，不能采用转速跟踪分析直接进行分析的特点，提出了将一次采样样本所包含的整周期数扩大一倍，加Ｈａｎｎｉｎｇ窗进行转速跟踪分析的方法，消除了低频滚振的影响，大大提高了升降速过程扭振各谐次幅值分析精度．仿真研究和应用实例证明，除瞬态分析时所分析的第一谐次幅值有较大的误差外，其余谐次幅值精度都很高，其中对稳态信号分析误差小于１％．

Studies on the method for increasing the accuracy in processing torsional vibration signal

In view of the fact that the existence of low-frequency rolling vibrations in the transient signals of torsion during speeding up or speeding down the engines makes it impossible to be processed directly by the revolution tracing analysis, the paper, while adopting the ratio correction method and the amplitude revision method of the 3-point convolution, puts forward a new revolution tracing measure by doubling the integral period numbers contained in a sample along with the use of Hanning windows to set off the affection of low-flequency rolling vibrations, so as to increase greatly the accuracy in analyzing torsional vibration signals during speeding up or speeding down the engines. Results obtained from simulative studies and real applications show that the proposed method has high accuracy, with the errors in steady-state signal analysis less than 1 % for the amplitudes of most harmonics (except for the amplitude of the first harmonic in transient signal analysis).