Composite control design for double-pendulum overhead cranes

Eliminating or reducing swing and enhancing the robustness of closed-loop systems have always been hot issues in crane control research. To this end, a novel composite control strategy combining adaptive input shaper and double closed-loop PD feedback is proposed for double-pendulum overhead cranes. Firstly, based on the dynamic model of the double-pendulum system, an extremely insensitive input shaper acting on the acceleration signal is designed. The shaped signal can realize the direct adjustment of multiple stages of the trolley movement. Secondly, this input shaper is combined with double closed-loop PD control used for the displacement and the hook swing angle to form a novel composite control structure. This structure makes the closed-loop system robust against uncertainties. In order to further improve the adaptability of the control structure to complex working conditions, an adaptive input shaper optimization algorithm is proposed. The algorithm is based on a novel performance function that reflects the residual swing. The pulse amplitude and action time of the shaper can be adjusted online through iterative calculation of acceleration and hook swing angle. Finally, the results show that the proposed control strategy can reduce the swing angle and ensure the robustness of the system. In addition, compared with other control strategies of the same type, it performs better in swing suppression.