Multi-body simulation of a human thumb joint by sliding surfaces

The development of anthropomorphic robotic grippers requires profound knowledge about the functionality of the human hand. For investigating its kinematic and dynamic properties, numerous biomechanical models have been established based on the assumption of fixed rotational axes. Even though this approach has proven to be accurate for most joints of the hand, difficulties have been reported for modelling the movement of the thumb. In order to investigate errors resulting from the thumb carpo-metacarpal joint, a new modelling approach is pursued that is based on contacting surfaces and stabilizing tissues. The joint is modelled as a multi-body system and driven by forces exerted by the cartilage contact, ligaments and muscles. Comparing the simulation results to anatomical literature reveals the capabilities of the proposed approach, but also the necessity of further improvements for its applicability in biomechanical investigations.