the parallel manipulator will have more than one the motion trends. So the parallel manipulator will lose control. Based on the bifurcation characteristics of a parallel manipulator at singularities
a new method to estimate the losing control configuration
which is called a configuration coefficient method
is presented for realizing the motion stability of parallel manipulators. The uncontrolled degree-of-freedoms can be estimated accurately by the method. The method can give the sequence of losing control components of the position and orientation
and also lay the background to control the motion of parallel manipulators.