Intelligent Control for Gantry Crane with Rigid-Flexible Coupling Characteristics Using Singular Perturbation Decomposition

While most existing studies overlook the flexible dynamics in large-span gantry systems, this paper develops a comprehensive rigid-flexible coupled dynamic model using the assumed mode method and Lagrange formulation. Based on this model, a systematic control framework is proposed to simultaneously address trajectory tracking, disturbance rejection, and flexible vibration suppression. The control strategy employs singular perturbation decomposition to separate the system into slow and fast subsystems. For the slow subsystem, an adaptive nonsingular fast terminal sliding mode controller is designed to enhance tracking precision and robustness. For the fast subsystem, a linear quadratic regulator is synthesized to actively suppress elastic vibrations. Theoretical analysis and numerical simulations demonstrate that the proposed method achieves superior performance compared to conventional approaches in terms of tracking accuracy, disturbance resistance, and vibration attenuation.