Application Of Independent Component Analysis In Mechanical Vibration Signals

Independent component analysis(ICA)is the approach to estimate original source signals using only the information of the mixed signals observed in each input channel.There are many applications of independent component analysis such as biomedical signal processing,image processing,general signal analysis,wireless communication,array signal processing and language signal processing.Considering its wide and attractive application,many research have studied ICA in the past twenty years so that ICA technique has been very much developed.However,ICA is still staying at the developing stage,and the investigation of its theory and application should be enhanced and improved further.Aim to the limitation of traditional signal processing in diesel engine monitoring and diagnosis,the theories and methodologies based on statistical signal processing,which are used to extract the independent component from mixture signals,have been researched.The paper consists of following parts:1)At first test the fourth cylinder pressure signal,vibration signal,top dead center signal of the 4135 diesel engine.Then the characteristics of the excitation and vibration response of cylinder cover are analyzed.2)A brief introduction to the development history and the current research status and applications of ICA,simple mathematical preliminaries in ICA technique were given,including the mathematical definition of ICA,the assumptions made about ICA problems and the mathematical theory and methods commonly used in ICA.3)Among the prime process of independent component analysis,whitening is very important.For the whitening process,its variance is studied.At the same time,for some independent component analysis algorithm it is dispensable to orthogonalize their output matrix,this is advantageous in the ICA algorithm can very good separate the mixed signal. 4)Application research of independent component analysis based on the negative entropy fixed point algorithm to decomposition of engine vibration signals has been studied in this paper.The experiment has carried on the independence and the non-gauss analysis to the mixed signal,proved this mixed signal conformed to the independent component analysis condition. And the performance of the algorithm has been illustrated by computation simulation experiment.The result display the performance of this algorithm is good.