Optimal design of a variable stiffness joint using permanent magnets

Myung Wook Hyun, Jeonghoon Yoo, Seoung Tack Hwang, Jun Ho Choi, Sungchul Kang, Seung Jong Kim

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Safety and performance are often required for robots interacting with humans. A variable stiffness joint (VSJ) is a useful device to reduce the shock against a human being by decreasing the joint stiffness quickly. In this study, a novel concept of VSJ using permanent magnets is suggested. It can have stronger stiffness compared with previous systems to satisfy payload conditions. However, this system requires a positioning mechanism to move the rotor to the axial direction for the variable stiffness. This study focuses on the optimal design of a permanent-magnet-type VSJ. The analysis is based on the finite-element simulation. The virtual work method is used to calculate the force and torque of VSJ. The modification of the initial concept model is preceded and a prototype is implemented and tested to compare analysis results. Also, the Halbach array concept is added to increase the torque of VSJ. The parameter optimization scheme is applied based on the design of experiments and a final design is suggested.

Original languageEnglish
Pages (from-to)2710-2712
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number6
Publication statusPublished - 2007 Jun


  • Design of experiments
  • Halbach array
  • Optimal design
  • Permanent magnet
  • Variable stiffness joint (VSJ)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


Dive into the research topics of 'Optimal design of a variable stiffness joint using permanent magnets'. Together they form a unique fingerprint.

Cite this