The ROAD CAT daily inspection vehicle is equipped with the JI system (Joint Inspection System), which consists of a system that measures the health of the expansion joints from the sound generated when the vehicle passes over the expansion joints, and a system for identifying the site of deformation (J-D Answer system*2).
The system measures health from the sound passing through the expansion joints, using a compact microphone placed near the rear wheel tire (photo-4) to measure the sound passing through the expansion joints and the vibration acceleration of the vehicle with an instrument (photo-5). The collected data is compared with the data when healthy, and the change (difference) is analyzed to evaluate the soundness.
The JI system, uses multiple laser displacement transducers (Photo-6) to measure the amount of unevenness on the road surface in the order of 1/10000th of a second while traveling at about 80 km/h, and it is possible to accurately measure the deformed part of the expansion joints by comparing it with the timing at which vibration occurs.
*2 Generic name for systems jointly developed by NEXCO East Japan, Central Japan, West Japan, NEXCO Research Institute, and Kozo Keikaku Engineering Inc.