Performance analysis and optimization of a rigid-flexible parallel manipulator

In order to meet the design requirements of friction stir welding equipment, a three-degree-of-freedom rigid-flexible 3UPS-UP-3Cable-Driven (3UPS-UP-3CD) parallel manipulator was applied to the main feed mechanism of the friction stir welding robot. The kinematics analysis of the new parallel manipulator was carried out, and the complete homogeneous dimensional Jacobian matrix of the 3UPS-UP-3CD manipulator was solved. Through kinematic performance analysis, the carrying capacity, dexterity and stiffness of 3UPS-UP-3CD manipulator are obviously better than 3UPS-UP mechanism, and the impact of cables on the workspace can also be eliminated by adjusting the dimension parameter. The composite quality workspace map of the manipulator was drawn, and the composite kinematic performance index was proposed. Multiobjective optimization was completed for 3UPS-UP-3CD manipulator, and its performance was improved. The dynamic analysis of the manipulator was carried out, and the driving forces of two mechanisms were calculated under two trajectories. The results showed that the maximum driving force of 3UPS-UP-3CD manipulator was lower than 3UPS-UP mechanism, which proved that 3UPS-UP-3CD manipulator was more suitable for heavy-duty conditions.