Stability Analysis of a Class of Nonlinear Controllers

The stability analysis of a class of nonlinear PD-plus-feedforward controllers is presented for the tracking control of rigid robot manipulators. The controller structure is composed of a nonlinear gain PD feedback controller and a manipulator dynamics feedforward term. The class of representations used for the nonlinear gain PD feedback controller is extended and global exponential stability is proved. Simulation results are included to illustrate the performance of this class of nonlinear controllers.