FSW robot system dimensional optimization and trajectory planning based on soft stiffness indices

Jing Zhao, Yaxing Duan, Biyun Xie, Ziqiang Zhang

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Serial robots provide an ideal alternative for friction stir welding of large-scale spatial curve welding seam due to their high flexibility and large workspace. However, the low stiffness of a serial robot will definitely affect its welding accuracy. In order to enhance the stiffness of the serial robot in completing friction stir welding tasks, this paper proposes a method of constructing the hybrid stiffness index. This method uses the sigmoid function to process the dexterity or joint limit index and applies it to the stiffness index as a weight coefficient. Then the soft stiffness index with dexterity constraint or joint limit constraint is constructed respectively, and these two hybrid stiffness indices have the same dimension as the stiffness index. Subsequently, the dimension synthesis of the ZK-500 serial robot is completed by maximizing the global soft stiffness index with dexterity constraint. Finally, based on the soft stiffness index with joint limit constraint, a joint trajectory planning algorithm for the ZK-500 robot and positioner system is proposed. The result of simulations shows that the soft stiffness index with a joint limit constraint can not only ensure the stiffness performance but also improve the smoothness of the joint trajectory in the robot trajectory planning task.

Original languageEnglish
Pages (from-to)88-97
Number of pages10
JournalJournal of Manufacturing Processes
StatePublished - Mar 2021

Bibliographical note

Publisher Copyright:
© 2020 The Society of Manufacturing Engineers


  • Joint trajectory planning
  • Robot performance index
  • Robotic FSW
  • Robotic dimension optimization

ASJC Scopus subject areas

  • Strategy and Management
  • Management Science and Operations Research
  • Industrial and Manufacturing Engineering


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