Modeling and nonlinear sliding mode controls of double pendulum cranes considering distributed mass beams, varying roped length and external disturbances

Most of the existing anti-swing control methods treat the crane as a single pendulum system with fixed rope length. In this paper, considering the varying rope length, the dynamic model of the double pendulum crane system with distributed mass beams (DMB) is established. Four versions of sliding mode control are proposed by utilizing the equivalent control strategy. The system responses of the hierarchical linear sliding mode control method based on velocity control and displacement control are analyzed. Meanwhile, based on the pole placement method, a state observer that adapts to the length variation of the suspension rope is proposed. On this basis, the nonlinear sliding model control methods utilizing the velocity control, including the NTSMC and FTSMC, are presented. Simulations and experiments are conducted. Results indicate the effectiveness of the proposed methods. The control method can ensure the asymptotic stability of the system in a finite time, maintain robustness in disturbances and adapt the varying rope length. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This paper establishes a dynamic model of a double pendulum crane system with distributed mass beams (DMB) taking into account the varying rope length, and proposes four versions of sliding mode control utilizing an equivalent control strategy. A state observer adaptive to the length variation of the suspension rope is designed based on the pole placement method. Nonlinear sliding model control methods utilizing velocity control are also presented. Simulations and experiments demonstrate the effectiveness of the proposed methods in ensuring system stability, robustness, and adaptability to varying rope length.