Application of Wavelet Analysis to the Suspension System Fault Detection of a Vehicle

This paper presents a fault detection method for suspension system using continuous wavelet transform. The presented method in which Morlet wave function is used to determine the natural frequencies and amplitudes of signal components and include maximum contribution to the signal energy at the specific scale. A complete vehicle model has been simulated by ADAMS software. Fault diagnosis has been investigated for dampers and upper damper bushings. Damper and bushing faults are supposed as decreasing in damping force and as a gap in bushing because of damage in rubber part. The vehicle considered to be excited under the frequency sweep input as road irregularities. At first, has been shown the inability of spectral analysis using power spectral density (PSD) function for analysing the mentioned systems specially in signals including transient characteristics and then to show the ability and accuracy of wavelet transform, which has been used for this purpose. After determination of faulty parts of suspension system by using signal energy distribution, by observing the changes in the natural frequencies and corresponding energy amplitudes, damper fault is distinguished from damper bushing fault.