A joint mechanism with variable stiffness

Yukihiro Funakawa, Atsushi Konno, Masaru Uchiyama

    Research output: Contribution to journalArticlepeer-review


    In the future, it is expected that robots will be able to play an active role in the real life alongside humans. Then, the softness of the robot is enumerated as one of the mechanical performances demanded for robots that coexist and cooperate with humans. Because, in case of a robot receives impact forces from an object, actuators may receive unpredictable damage by the impact forces. If the robot has mechanical softness, it is possible to reduce the impact forces. In such cases it is necessary to adjust the stiffness of the joint. Then, the reaction forces at the time of impact can be passively absorbed by lowering the joint stiffness. On the other hand, when torque requirement is high, a variable stiffness design helps raise the joint stiffness. Design of such a variable stiffness mechanism is proposed in this paper. The stiffness characteristics are evaluated. Analysis is conducted to verify feasibility of mounting it on actual robots.

    Original languageEnglish
    Pages (from-to)2045-2051
    Number of pages7
    JournalNihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
    Issue number8
    Publication statusPublished - 2008 Aug


    • Linear spring
    • Mechanical engineering
    • Mechanism
    • Robot
    • Variable stiffness

    ASJC Scopus subject areas

    • Mechanics of Materials
    • Mechanical Engineering
    • Industrial and Manufacturing Engineering


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