Gravity canceled flexible joint mechanism

Kei Mikami, Yoshiki Ono, Toshio Morita

Research output: Contribution to journalArticlepeer-review


In this paper, we propose a mechanism which is named "gravity canceled flexible joint," since a passive flexible joint attracts attention by its collision safety. Manipulators with a passive flexible joint are expected to work in a human environment. However, manipulators with the passive flexible joint have some problems. One is that there is steady position error because of displacement of flexible joints by self-weight. Moreover, the manipulator power and the back drivable range are reduced by self-weight. Mechanical self-weight compensation become efficient for overcoming this problem. Therefore, this paper proposes the passive flexible joint with self-weight compensation mechanism that equips the features with compactness and durability. In order to satisfy these requirements, this research focuses on a end cam. By using the end cam, nonlinear rotational spring is able to design from determining a pressure angle of end cam. Both the self-weight compensation and the passive flexibility are achieved by end cams. From position control experiments, it is clarified that the proposed mechanism can compensate steady position error and showed utility as a joint mechanism.

Original languageEnglish
Pages (from-to)3021-3028
Number of pages8
JournalNihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
Issue number771
Publication statusPublished - 2010 Nov


  • End cam
  • Flexible joint
  • Manipulator
  • Mechanism
  • Robot
  • Self-Weight compensation

ASJC Scopus subject areas

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


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