Kinematic comparison of Hybrid II test dummy to wheelchair user

Hybrid test dummies provide a safe alternative to human subjects when inves tigating mechanisms of wheelchair tips and falls. The data that researchers acquire from these test dummies are more useful if the test dummy represen ts the population beings studied. The goal of this study was to measure the validity of a 50th percentile Hybrid II test dummy (HTD) as an accurate re presentation of a wheelchair user. A test pilot with T8 paraplegia due to t raumatic spinal cord injury served as a basis for validation. Simple modifi cations were made to the HTD to approximate the trunk stability characteris tics of a person with a spinal cord injury. An HTD, a modified HTD, and a h uman test pilot were seated in an electric-powered wheelchair and several b raking tests performed. The standard HTD underestimated the kinematics when compared to the test pilot. The modified HTD had less trunk stability than the standard HTD during all braking methods. The modified HTD and wheelcha ir test pilot had similar trunk stability characteristics during kill switc h and joystick full-reverse braking conditions. The modified HTD is a satis factory representation of a wheelchair user with a spinal cord injury; howe ver, the modified test dummy underestimates the trunk dynamics during the l ess extreme joystick release braking. Work should continue on the developme nt of a low-speed, low-impact test dummy that emulates the wheelchair user population. (C) 2001 IPEM. Published by Elsevier Science Ltd. All rights re served.