Adaptive sway reduction for tower crane systems with varying cable lengths

For practical underactuated tower cranes, vertical payload motion is always involved to increase the working efficiency, making the control problem more complex. Most existing control methods are designed based on linearized crane dynamics and require exact plant parameters. To solve these problems, the dynamic model of tower cranes with varying cable lengths is established firstly, on whose basis, an adaptive sway reduction control method is proposed. To our knowledge, the designed control method yields the first closed-loop control solution, with guaranteed theoretical analysis, to successfully address the tower crane anti-swing and positioning problem in the presence of varying cable lengths. The model and control method are simulated by MATLAB/Simulink, and the simulation results show that the anti-swing performance is significantly enhanced by more than 63.22%, compared with PD method. Considering there are several control gains in the designed law, optimization of control gains based on optimization methods will be conducted.