Abstract
We have developed three inertial measurement processing techniques to measure the longitudinal level of tracks using the devices mounted on the commercial shinkansen trains. Two of them, labeled as the ”Frequency variable difference filter” and the ”Speed variable moving summation”, employ digital processing, while the other employs analogue processing applying a frequency variable low-pass filter. Through a series of the simulation tests, the above all methods were found to be capable of deriving a 10 m versine longitudinal level directly from the measured acceleration with high precision without causing any waveform distortion. An experimental prototype of a digital inertial device applying the ”Frequency variable difference filter” that can help to minimize the processing load was produced, and its reliability was investigated. As a result, the output by means of the proposed prototype revealed good correlation with the data collected from an existing track geometry car. After the successful test results were obtained, the devices have so far been manufactured and installed in six N700 commercial trains. The repeatability was also found to be excellent, thus the device is expected to detect even a slight change of the track.
