A theoretical improvement on wobble and nutation of fluid core earth model

Based on classical dynamical equation on rotation offluid core Earth, a associated dynamical equation containing both nutation and wobble of Earth rotation have been deduced through introducing motion of nutation frame system withrespect to inertial spatial frame. Therefore, we have defined CIP axis of fluid core Earth and resolved it. It indicated that the new method overcame some problem which can'tbe solved by traditional method, and predigested complexity in traditional process. Itis remarkable that wobble and nutation can be solved synchronously. In particular,theoretically TOM in theory of Smith M. L.(1977) only is a special solution of new dynamical equation.