Optimal Trajectory-Based Control of 3-D Dual Rotary Cranes for Payload Dynamic Regulation in Complex Environments

With flexible payload adjustment ability and large load capacity, dual rotary cranes (DRCs) provide effective solutions for various complex hoisting tasks. At present, the control research for DRCs mostly focuses on two-dimensional space (restricting workspace and efficiency), or lacks the consideration of DRC dynamic characteristics and the practical demands for the dynamic regulation of payload positions and attitudes, which makes it difficult to handle hoisting tasks in complex environments. To tackle these issues, this article proposes an optimal trajectory-based motion control method for three-dimensional (3-D) DRCs in complex environments, effectively tackling key challenges encountered by DRCs operating in 3-D space. The proposed method achieves dynamic regulation of payload position and attitude by DRCs in 3-D space for the first time, constraining payload velocity and acceleration within reasonable ranges while avoiding obstacles, which represents an advancement in enhancing the efficiency and safety of 3-D DRC operations in complex environments. Specifically, the coupling relationship between the actuated boom motions and the non-actuated payload motions in 3-D space is mathematically solved, which provides the foundation of indirect payload regulation through boom control. Moreover, by introducing multiple performance indicators during optimization, the proposed method ensures satisfactory payload transient performance while maintaining a safe distance from obstacles. Additionally, by the analysis of steady-state equilibrium conditions and the reasonable passing time allocation of virtual via-points, coordinated boom motions with payload swing suppression are realized, ensuring transportation smoothness. Finally, hardware experiments are conducted considering collision-free payload transportation through reciprocating boom pitch/rotation motions, which verifies the effectiveness and practical performance of the proposed method.