Three-Dimensional Reach Kinematics of the Upper Extremity in a Dynamic Vehicle Environment

Simulation of reach movements is an essential component for proactive ergonomic analysis in digital human modeling and for numerous applications in vehicle design. Most studies on reach kinematics described human movements in static conditions. Earlier studies of reach performance in vibration environments focused mainly on fingertip deviation without considering multi-body dynamics. However, for the proper assessment of reach performance under whole-body vibration exposure, a multi-body biodynamic model needs to be developed. This study analyzes three dimensional reach kinematics of the upper extremity during in-vehicle operations, using a multi-segmental model of the upper body in the vibratory environment. The goals are to identify the characteristics of upper body reach movements and to investigate vibration-induced changes in joint kinematics. Thirteen subjects reached to four target directions in the right hemisphere. The results show differences and similarities in the characteristics of movement patterns of upper body segments for static and dynamic environments. Identification of movement patterns in terms of joint kinematics can be used to determine some biodynamic principles of upper body segments coordination in reach motion.