Research On Vibration Signal Resampling And Rotating Speed Soft Measurement Technology

Vibration signals are often used to reflect the state information in the process of mechanical operation.Accurate and effective acquisition of vibration signals is of great significance for condition monitoring and fault diagnosis of mechanical equipmentVibration signals collected at high frequencies contain abundant frequency components and have high resolution in time domain,they are widely used in engineering practice.The improvement of time domain resolution will lead to the decrease of frequency domain resolution.In order to solve the contradiction between time-domain resolution and frequency-domain resolution,a new method of vibration signal resampling based on piecewise linear interpolation is designed.The results of simulation and experiment show that the algorithm has certain advantages in structure simplicity,calculation speed and spectral accuracy.In the process of resampling,the problem of mirror image and spectrum aliasing can not be neglected.The solution is to filter high frequency components through low pass filter.Finite Impulse Response(FIR)filter has linear phase characteristics,which can ensure that the waveform in time domain is not distorted after filtering.Frequency sampling method is the main method in filter design.It can directly design the filter in frequency domain.It is suitable for optimal design and the performance of the filter can be optimized.In this paper,an improved genetic algorithm is used to optimize the design process of FIR filters,which improves the stopband attenuation of FIR filters significantly compared with the look-up table method.The rotating speed of rotating machinery is an important parameter in the process of mechanical operation.For the acquisition device without special speed channel,it is necessary to use soft sensor to measure the speed.Based on the principle of waveform conversion,a soft sensing method is designed in this paper.The algorithm is validated under different signal-to-noise ratios and different rotational speeds.The results show that the method has high measurement accuracy in a certain range of signal-to-noise ratios and is less sensitive to the change of rotational speed,which proves that the method is effective.