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1 2009

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An attempt of the application of matching pursuit mp with Gabor dictionary for evaluation of ride comfort disturbance level

Grzegożek W., Szczygieł J.

Journal of KONES

2009

Vol. 16, No. 2

149-158

Ride comfort has always been considered to be essentialfor vehicle development. Nowadays it is one of aspects of wehicle industry that is getting more and more important. Disturbances in vehicle motion, for example drive across an obstacle or drive of a rail vehicle across the transition curve may be the reason for ride comfort disturbances. These excitation values may define the subjective negative comfort assessment by a passenger or a driver. Sudden changes of acceleration with low frequencies are particularly perceptible. That is why the attempts of evaluation of these disturbances are included in standards as PCT and PDE indexes for rail vehicles. In order to designate these indexes filtration of the recorded lateral acceleration runs is done. The values of changes of lateral acceleration, of lateral jerk and roll rate in time intervals are defined. This kind of analysis in which only the amplitudes of values measured were taken into account and in which 2 Hz filter was used may cause discrepancy between subjective assessment and evaluated level of vibration. Wavelet transform that is the tool of time-frequency analysis makes non-stationary signals such as acceleration signals in case of comfort disturbances possible. The problem of evaluation of vibration level that is basedon wavelet transform analysis appears. In order to evaluate this vibration level algorithm of matching pursuit MP may be used to match the mother wavelet to the recorded signal in the best way possible. The article presents an attempt of matching pursuit algorithm with Gabor dictionary for evaluation of the discomfort level that was based on the run recorded in the tram.