The current research conducted a cross-validation between an infrared motion capture system and an electromechanical motion capture device. No differences were found between the motion capture methods in shoulder and elbow angles. However, differences were found between the motion capture methods on distances of hand movements and actor location in space. Results of the current study indicate electromechanical motion capture devices are too inaccurate to use for validating digital human models unless the ultimate application of the model does not require millimeter accuracy or an absolute location in space. If one is primarily interested in joint angles, and distances are secondary, an electromechanical device is acceptable.
The Crew Impact Attenuation System (CIAS) is the energy-absorbing strut concept that dampens Orion Crew Exploration Vehicle (CEV) landing loads to levels sustainable by the crew. Significant COM variations across suited crew configurations would amplify the inertial effects of the pallet and potentially create unacceptable crew loading during launch and landing. The objective of this study was to obtain data needed for dynamic simulation models by quantifying the effects https://ntrs.nasa.gov/search.jsp?R=20100008465 2018-05-09T16:53:04+00:00Z of posture, suit components, and the expected range of anthropometry on the COM of a seated individual.Several elements are required for the COM calculation of a suited human in a seated position: anthropometry, body segment mass, suit component mass, suit component location relative to the body, and joint angles defining the seated posture. Three-dimensional (3D) human body models, suit mass data, and vector calculus were utilized to compute the COM positions for 12 boundary manikins in two different seated postures.The analysis focused on two objectives: (1) quantify how much the wholebody COM varied from the smallest to largest subject and (2) quantify the effects of the suit components on the overall COM in each seat configuration. The location of the anterior-posterior COM varied across all boundary manikins by about 7 cm, and the vertical COM varied by approximately 9 to 10 cm. The mediolateral COM varied by 1.2 cm from the midline sagittal plane for both seat configurations. The suit components caused an anterior shift of the total COM by approximately 2 cm and a shift to the right along the mediolateral axis of 0.4 cm for both seat configurations. When the seat configuration was in the standard posture the suited vertical COM shifted inferiorly by as much as 1 cm, whereas in the CEV posture the vertical COM had no appreciable change. These general differences were due to the high proportion of suit mass located in the boots and lower legs and their corresponding distance from the body COM, as well as to the prevalence of suit components on the right side of the body.
Body armor for law enforcement personnel is critical in ensuring the safety and protection of these individuals, though literature on the impact of body armor design on task performance is not readily available in the public domain. The objective of this study was to assess the effects of body armor design on range of motion for the shoulder, neck, and back. Three armor configurations (no armor (Baseline), concealable body armor (CBA), and external body armor (EBA)) were studied. Results indicated that for most measurements, the EBA condition resulted in significantly lower ranges of motion that the other configurations and most measurements were similar between the baseline and CBA condition. Specific differences in the body armor designs (e.g., the presence of shoulder protectors) may be responsible for many of these findings. Therefore, changes to current armor designs should carefully consider the impacts of additional coverage elements on human movement.
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