When is the set of base parameter values physically impossible?

A necessary and sufficient condition has been shown for a set of base parameters to determine a inertial matrix to be positive definite for each configuration of a manipulator after continuous change of each joint variable of the manipulator is approximately considered as a finite set of discrete points. The condition enables us to judge if a set of estimated base-parameter values determines the inertial matrix to be always positive definite or not. A method also has been proposed to modify the estimated base-parameter values such that the set of them determines the inertial matrix to be always positive definite after it is judged not to do