Design of a Novel Compliant Safe Robot Joint with Multiple Working States

Zerui Wang, Hiu Man Yip, David Navarro Alarcon, Peng Li, Yun Hui Liu, Dong Sun, Hesheng Wang, Tak Hong Cheung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)


This paper presents the design and development of a novel compliant safe joint (CSJ). The principle of operation of the CSJ is based on a cam-like transmission mechanism, which we call the bridge. The cam profile on the stationary bridge is designed to have multiple regions, which allow the CSJ to passively achieve multiple working states. The proposed joint behaves as a normal rigid joint when the load is smaller than a preset threshold, shifts into the flexible state when the load exceeds the threshold, and switches into the free state in which the motion cannot be transmitted from the motor to the output shaft. In order to achieve a compact modular assembly, the joint's components are designed to have the shape of a hollow cylinder and to be installed around the motor. We analyze how the key dimension parameters affect the torque threshold and the joint's stiffness. Experiments are conducted to validate the working principle and verify the performance of the joint.
Original languageEnglish
Article number7328739
Pages (from-to)1193-1198
Number of pages6
JournalIEEE/ASME Transactions on Mechatronics
Issue number2
Publication statusPublished - 1 Apr 2016
Externally publishedYes


  • Compliant joint
  • mechanical design
  • physical human-robot interaction
  • safety

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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