Adaptive integral sliding mode control with payload sway reduction for 4-DOF tower crane systems

An adaptive integral sliding mode control (AISMC) method with payload sway reduction is presented for 4-DOF tower cranes in this paper. The designed controller consists of three parts: The integral sliding mode control is used to provide the robust behavior; the adaptive control is utilized to present the adaptive performance; the swing-damping term is added to suppress and eliminate the payload swing angles. Different from existing sliding mode control methods presenting with chattering phenomenon, the proposed AISMC method is essentially continuous and chattering free. Moreover, the accurate values of the system parameters including the payload mass, the trolley mass, the cable length, the moment of inertia of the jib, the friction-related coefficients are not required for the designed controller due to the adaptive control. Lyapunov-based analysis and LaSalle's invariance principle are employed to support the theoretical derivations without linearizing the nonlinear dynamics. Experimental results are illustrated to show the superior control performance of the designed controller.