A fuzzy uncertainty compensator for manipulator trajectory tracking

A fuzzy logic compensating (FLC) scheme is proposed to enhance the conventional computed-torque control (CTC) structure of manipulators. The control scheme is based on the combination of a classical CTC and FLC, and the resulting control scheme has a simple structure with improved robustness. Further improvement of the performance of the FLC scheme is achieved through automatic tuning of a weight parameter α leading to a self-tuning fuzzy logic compensator, so the system uncertainty can be compensated very well. By taking into account the full nonlinear nature of the robotic dynamics, the overall closed-loop system is shown to be asymptotically stable. Experimental results demonstrate the effectiveness of the computed torque and fuzzy compensation scheme to control a manipulator during a trajectory tracking task.