Study For Vibration Signal Filtering Of Block-forming Machine Based On Wavelet Transform

With the continuous development of our social economy and the worsening of the natural environment, our country pay more and more attention to energy conservation and emissions reduction and environmental protection,sintered bricks which have technology backwardness and severe collateral damage to the environment is gradually replaced by some environ-mental protection new blocks.Vibration system is the core component of the block-forming machine,and the block vibration process has important i-nfluence on the quality of the blocks.The vibration signal of block-forming machine is very complex,In the course of work,the mold of block-forming machine not only receives stationary vibration signal which produced by the vibration table but also the non-stationary signal that caused by impact vibration between various components.The signal which collected form the mould,has work frequency of the vibration table,frequency doubling,non-integral harmonic interference,and other strong interference signal,this makes the block molding machine working state monitoring, research on block molding machine troubleshooting and block-forming machine vibration system becomes difficult.Through the study of block molding machine vibration system, and the theoretical study of block forming,work out the components of block vibration signal.This paper summarizes classical filtering methods,figure out in the condition which assumed effective signal and noise signal spectrum is separated,and that cannot adapt to the modern vibration signal filtering requirements,modern filters such as wiener filtering and kalman filtering is based on their respective conditions,If the signal can’t satisfy these assumptions, the denoising effect can not meet requirements.Wavelet transform as a new kind of vibration signal processing method, has been used in the field of signal processing in engineering It makes the signals of different frequency decomposed to non-overlapping band,by introducing variable scale factor and shift factor,realize adjustable time-frequency window,it is self-adaption,wavelet transform provides a new method on vibration signal filtering.Paper analyzed the three commonly used methods of wavelet analysis:(1)Spatially selective noise filtration;(2)Mold maximum de-noising method;(3)Wavelet threshold de-noising method.This paper uses wavelet threshold de-noising method for block-forming machine’s mold and frame vibration signal denoising.Through MATLAB simulation illustrates the steps of using the wavelet threshold denoising method in detail,because hard and soft threshold functions are insufficient,so this paper use simulation compares the four improved threshold function,and selects the better one to filtering the signal of block-forming machines.Through analysis the signal which after filtering, shows that wavelet analysis theory is useful to block-forming machine vibration signal denoising.