Human-and-Humanoid Motion - Distinguish Between Safe and Risky Mode

This paper explores a question rarely addressed in studies of human/humanoid gait and related movements. In the case of slow motion with the possibility of stopping and retreating, the human/humanoid has a full control over his movements, while in the latter case called “normal” motion he falls practically out of control. The idea might arise to relate the first situation with stability and the latter with instability. However, the notion of stability, defined in the system theory, does not agree with this and in order to avoid the confusion we here suggest the terms safe and risky motions.