Abstract
This paper suggests that pavement irregularity is extracted from the vibration acceleration data by independent component analysis (ICA). Automobiles consist of many movable parts and, these are sources of vibrations. So, the vertical accelerations of unsprung masses are evoked by road irregularity, engine's vibration, suspensions' vibrations, and so on. Eight accelerometers are set up, and measured unsprung of the vehicle. ICA can divide an original signal from mixed signals. The road surface to measure is a known road surface and an unknown road surface. The known road surface is a tile road. The vehicle changed only the left rear wheel into 16 inches tire, 17 inch tire, and temporary tire. Similar waveforms are extracted in all tire patterns from the results of ICA on unknown road condition. Therefore, the result of ICA extracted the same characteristics of road irregularity. From the results of ICA on known road condition, reads the peak frequency at tiles' frequency and its multiples, so the information of road irregularity was extracted from measured accelerations with ICA. From PSD of waveform extracted by ICA, the vibration of low frequency is weaker on wet condition than dry condition.
Keywords: vibration, measurement, automobile, independent component analysis (ICA).