Measuring the Displacement of a Vehicle Body with and Optical Measuring System (Motion Captrure). 2019-01-0393
The 3D measurement of a body displacement on a moving vehicle needs a quite challenging process. Well-known displacement measuring device such as a dial or strain guage can estimate the displacement in very limited areas. An Accelerometer also can estimate body motion but it has an accumulated error and a bias issue for acquisition of exact displacements. However, An optical measuring (Motion Capture) method which use markers and multiple cameras can read 3D coordinators directly and carry out those measurements well.
In this paper, first, we determined how to extract a body displacement from global motion. Then we suggested a combining measurement methodology which use a motion capture and an accelerometer simultaneously, but failed to acquire exact displacement. Along this process, we showed an accuracy comparison between a motion capture and an accelerometer to measure a displacement.
Next We verified the measuring error of the motion capture(±0.5mm) and considered data smoothing techniques, the low pass filter and the weighted moving average, to improve the measuring accuracy. Finally we applied the motion capture measuring methodology for real static and dynamic cases. For static case, we measured the displacement around tailgate area on vehicle twist test and reveal body deformation modes in 3D. For dynamic case, we measured full vehicle body displacement on a road simulator and traced body motion and deformations on a moving vehicle.
Jung Woo Hur, Joong Jei Ahn, Joo Tae Oh