New control algorithm of loss-DOF serial manipulators near singular configurations

A methodology for the exact velocity inverse of n-DOF(n<6) serial manipulators is presented. For loss-DOF manipulators, the independent Cartesian variables must be equal to the joint variables, and the remaining (6-n) Cartesian. variables will linearly depend on these independent variables. The developed methodology uses the properties of reciprocal screws to determine the independent controllable variables in the Cartesian space, and the mapping between the controllable velocity components in the Cartesian space and the joint variables in the joint space is remolded and becomes uniquely defined. This paper also presents a singularity analysis method for loss-DOF manipulators depending on different independent Cartesian velocity component groups. As an example, a 5-DOF manipulator is analyzed to demonstrate the effectiveness of the methodology.