Stability analysis of decentralized adaptive fuzzy logic control for robot arm tracking

The global ultimate stability of a decentralized adaptive fuzzy controller for trajectory tracking of robot manipulators is presented. Employing a PD control and a cubic feedback to ensure the global stability for robot tracking, an adaptive fuzzy logic scheme is incorporated to reduce the effects of interconnections, frictions, gravity force and other uncertainties. It shows that with a very limited knowledge on the sizes of interconnection terms, the controller guarantees the global ultimate boundedness of tracking errors. As the overall controller is based on a decentralized controller structure, it results in very simple fuzzy rules which can be implemented in most robot systems without hardware alternation. The simulation results are included for verification