Comprehensive Measurement in Whole-Body Vibration

Abstract

Accurate measurements of human response to whole-body vibration are essential to any conclusions about the health risks, discomfort, and assessment of suspension systems in vibration environments. While accelerometers are traditionally considered the main measurement tools in whole-body vibration studies, their measurements become questionable when they are attached to inclined surfaces or when the motion has coupled components in multiple directions. Current measurement correction methodologies are subjective and limited to simple cases. A comprehensive correction methodology using inertial sensors was used in this work to quantify human response under single fore-aft, single-vertical, and multiple-axis whole-body vibration of twelve seated subjects with supported-backrest and unsupported-backrest upright posture. Vibration files of white noise random signals with frequency content of 0.5-12 Hz and vibration magnitude of 1.8 m/s 2 RMS were used in the testing. The results have shown considerable differences in the transmissibility measurements without proper correction. The work presented has the potential to standardize experimentation in whole-body vibration and make measurements more accurate and defined across labs.

Effect of lumbar support on human-head movement and discomfort in whole-body vibration

“…Accelerometers are traditionally considered as the main measurement tools in WBV studies, but their measurements become questionable when they are attached to inclined surfaces, such as the contours of the human body, or when the motion has multiple directions. To circumvent this problem, inertial sensors were used in this work, and the acceleration data were corrected as described by DeShaw and Rahmatalla [31].…”

“…The participants wore an inertial sensor at the forehead region (MTx inertial tracker, Xsens Technologies, Enschede, Netherlands) ( Fig. 4), which was rigidly attached to a head-worn halo similar to that used in previous studies [31,32]. An additional sensor was rigidly attached to the aluminum seat frame to measure the input motion to the human.…”

“…Each inertial sensor had the capability to record the acceleration data at 120 Hz and the orientation matrix of the sensor local coordinate system relative to the global coordinate system. The data obtained from the inertial sensors were verified with a traditional tri-axial DC accelerometer (Dytran 7523A1, Chatsworth, CA) as outlined by DeShaw and Rahmatalla [31]. Additional retroreflective markers were attached to the participants to capture motion data; however, the data were not used in this work.…”

Identification of damping and stiffness parameters of cervical and lumbar spines of supine humans under vertical whole-body vibration

“…Vertical translational vibration motions (frequency range of 0.5-20 Hz and RMS magnitude of 2.0 m/s 2 ) transmitted to the subject's head, chest, pelvis, and lower leg regions were measured using inertial sensors. 22…”

Whole-body vibration transmissibility in supine humans: Effects of board litter and neck collar

“…For application in the study, the local (xyz) linear acceleration was transformed into the global (XYZ) reference system using a rotation matrix (DeShaw and Rahmatalla, 2012). The rotation matrix is found from the quaternion output for each sensor as seen in the following equation (Xsens, 2009).…”