Fuzzy Logic Control of an Uncertain Manipulator With Full-State Constraints and Disturbance Observer

In this paper, a fuzzy logic control strategy is proposed for solving trajectory tracking control issues of an uncertain manipulator. Fuzzy logic is utilized to compensate for nonlinear uncertainties in manipulator dynamics and full-state constraints are involved in full-state feedback controller design for ensuring motion constraints during movement processes. Disturbance observer (DO) is designed to counteract the effects of unknown nonlinear disturbances caused by friction force or other various forms of disturbance. Combining with Lyapunov theory and back-stepping method, the proposed method can guarantee error signals in closed-loop system semi-globally uniformly bounded (SGUB). In view of safe operation, tangent barrier Lyapunov functions (tBLFs) are chosen to maintain joint angle and velocity in a predefined constrained region in tracking processes. Finally, simulation results are carried out to show the effectiveness of our proposed control strategy.