Structure optimization of a six-degree-of-freedom pose adjustment platform for large-scale flange assembly

To address the assembly scenarios of large-scale heterogeneous flange test pieces (2,000 kg), a Stewart 6-DOF adjustment platform is employed for pose regulation. However, the design faces complex optimization challenges involving coupled constraints of space, heavy-duty load capacity, and maneuvering performance. This paper conducts structural optimization and simulation verification to address these issues. By selecting the radii and the short-edge distribution angles of the upper and lower platforms as optimization variables, a multi-objective optimization model is established. To ensure practical engineering applicability, a hard constraint of (Rp < Rb) is imposed. The objective functions incorporate reachable workspace (V), Global Dexterity Index (GDI), and Global Force Index (GFI). The theoretical optimal solution set is obtained using the NSGA-II algorithm. Considering the engineering requirements for heavy-duty assembly, the final design scheme is selected by prioritizing load capacity, followed by kinematic dexterity and workspace adaptability, with subsequent engineering rounding of the parameters. Re-calculation of the performance indices shows that the relative errors after rounding are 2.15% for V, 0.235% for GDI, and 0.05% for GFI, respectively. Finally, static simulation is performed for verification. The results indicate that the optimized structure possesses a 2,000 kg load-bearing capacity while maintaining sufficient kinematic flexibility and workspace, meeting the assembly requirements for large-scale heterogeneous flanges. This study effectively bridges the gap between theoretical algorithm results and engineering practice, providing a valuable reference for the industrial design of similar heavy-duty adjustment platforms.