Abstract
Humans can execute various motor tasks in daily life, sports, and so on. Since human body as musculoskeletal system has multiple degrees of freedom, the notion of motor primitive is one of the keys for human behavior generation and motor control. One of the acquisition strategies of motor primitives is that action units as motor primitives are extracted from transitional movements in physical structure of body and environment. Our purpose is extraction of motor primitives from interaction between a body and a environment. We considered about baby motor primitive acquisition. Motor commands which are random walk with a drift generate for searching a body and environment dynamics. The motor command is sufficient to generate behavior for baby, and a physical information structure appears as frequency distribution of baby's head direction. In conclusion, motor primitives are successfully extracted as transitional movement between one stable area to another area.
