근거리 광학식 계측기법을 적용한 수중 운동계측시스템 개발

Abstract

An underwater motion measurement system(UMMS) was constructed for applications to the model basin. A commercial motion capture system, FALCON of MotionAnalysis Corp., which corrects automatically the distortion caused by refraction of the light passing through water and air, was adopted for underwater motion measurement. The modifications of FALCON system were performed: waterproofing camera housings, markers, connectors, and a new blue ring lighter. The accuracy of the motion measurement was obtained within the calibration error of 0.87mm in average and 0.89mm in standard deviation for the distance of 500mm between two markers on the calibration device. The volume of 2100mm(length)× 2100mm(breadth) ×2300mm(Height) was covered with 4 cameras of the UMMS. For the performance verification, motion measurement test of a vertical mooring chain model excited at the top end was carried out. The 3D motions of mooring model were measured with variable amplitude and period of the forced excitation. Higher order motions of the mooring model were observed as the excitation period decreases. The performance of the system was verified by successfully measuring 3D motion of mooring model.