Adaptive fuzzy nonlinear anti-sway trajectory tracking control of uncertain overhead cranes with high-speed load hoisting motion

In the present paper, an adaptive fuzzy nonlinear control (AFNC) law is proposed for the anti-sway trajectory tracking of uncertain overhead cranes with high-speed hoisting motion. In the propsoed AFNC, fuzzy systems are utilized in two different ways. One is for fuzzy uncertainty observer (FUO) and the other is for fuzzy nonlinear control (FNC). Two FUOs are employed to cope with system uncertainties in an adaptive manner, while an FNC is developed to reduce the high-frequency chattering effect of variable structure control. Through the stability analysis and numerical simulations, it is shown that the proposed AFNC guarantees robust asymptotic stability of trajectory tracking error dynamics in trolley and hoisting motion as well as in sway dynamics, against not only the coupling effect of hoisting velocity and hoisting rope length but also system uncertainties such as system parameter variations, external wind disturbance, and unknown actuator nonlinaerities.