Artificial Life and Robotics

, Volume 15, Issue 1, pp 72–76 | Cite as

Development of a variable stiffness joint drive module and experimental results of joint angle control

  • Jun KobayashiEmail author
  • Katsuhiro Okumura
  • Yasuhiro Watanabe
  • Noriyoshi Suzuki
Original Article


Two prototypes of variable stiffness joint drive modules imitating a human joint structure are presented. A human joint is driven by a pair of flexor and extensor muscles that work antagonistically. The stiffness of the joint is adjusted by their co-contraction. Such a structure was given to the joint drive module so that it could achieve a variable stiffness property. The joint is driven by two wires with nonlinear springs. Thanks to the nonlinearity of the springs, the stiffness of the joint can be adjusted by quasi-co-contraction of the wires. With the first prototype, the stiffness adjustability of the joint was empirically confirmed. Regarding joint angle control, a three-layered proportional integral derivative (PID) control algorithm was implemented in the second prototype, and it was verified that the control algorithm worked properly.

Key words

Variable stiffness Antagonistic wire-driven mechanism Joint angle control 


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Copyright information

© International Symposium on Artificial Life and Robotics (ISAROB). 2010

Authors and Affiliations

  • Jun Kobayashi
    • 1
    Email author
  • Katsuhiro Okumura
    • 2
  • Yasuhiro Watanabe
    • 2
  • Noriyoshi Suzuki
    • 3
  1. 1.Department of Systems Design and InformaticsKyushu Institute of TechnologyFukuokaJapan
  2. 2.Fukuoka Industrial Technology CenterFukuokaJapan
  3. 3.Mitsuwa, Iizuka, FukuokaJapan

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