Human hand kinematics based on MRI imaging

Anthropomorphic robot hands have come to a technical level where understanding exact human hand kinematics becomes relevant, e.g. the hand/arm system that is presently being developed at DLR. Human hand kinematics have been investigated through cadaver hands and optical motion tracking of surface markers. A problem with the former is that tissue properties might be altered due to tissue necrosis. With the latter, the motion of the skin relative to the bones leads to so called soft tissue artifacts (STA) that negatively influence the quality of the results. To allow in vivo measurements and to avoid STA, we recorded finger postures by magnetic resonance imaging (MRI). We used a method similar to the one described by Miyata et al. in 2005, but with a much larger number of hand postures, resulting in a model with multi-degree-of-freedom (multi-DoF) joints.