ANGULAR RATE SENSOR JOINT KINEMATICS APPLICATIONS

High speed rotary motion of complex joints were quantified with triaxi al angular rare sensors. Angular rate sensors were mounted to rigid li nks on either side of a joint to measure angular velocities about thre e orthogonal sensor axes. After collecting the data, the angular veloc ity vector of each sensor was transformed to local link axes and integ rated to obtain the incremental change in angular position for each ri me step. Using the angular position time histories, a transformation m atrix between the reference frame of each link was calculated. Increme ntal Eulerian rotations from the transformation matrix were calculated using an axis system defined for the joint. Summation of the the incr emental Eulerian rotations produced the angular position of the joint in terms of the standard axes. This procedure is illustrated by applyi ng it to joint motion of the ankle, the spine, and the neck of crash d ummies during impact tests. The methodology exhibited an accuracy of l ess than 5% error, improved flexibility over photographic techniques, and the ability to examine 3-dimensional motion.