Nonlinear Spring system for collision safety

Jung Jun Park, Hwi Su Kim, Jae Bok Song

Research output: Chapter in Book/Report/Conference proceedingConference contribution

67 Citations (Scopus)


Collision safety between humans and robots has, drawn much attention since service robots are increasingly, being used in human environments. A safe robot arm based on, passive compliance can usually provide faster and more reliable, responses for dynamic collision than an active one involving, sensors and actuators. Since both positioning accuracy and, collision safety of the robot arm are equally important, a robot, arm should have very low stiffness when subjected to a collision, force greater than the injury tolerance, but should otherwise, maintain very high stiffness. To implement these requirements, ,a novel safe joint mechanism (SJM-II) which has much smaller, size and lighter weight than the previous model, is proposed in, this research. The SJM-II has the advantage of nonlinear spring, which is achieved using only passive mechanical elements such, as linear springs and a double-slider mechanism. Various, analyses and experiments on static and dynamic collisions show, that stiffness of the SJM-II is kept very high against an external, torque less than the predetermined threshold torque, but, abruptly drops when the input torque exceeds this threshold, ,thereby guaranteeing positioning accuracy and collision safety., Furthermore, a robot arm with two SJM-IIs is verified to, achieve collision safety in 2D space.

Original languageEnglish
Title of host publication2009 IEEE International Conference on Robotics and Automation, ICRA '09
Number of pages6
Publication statusPublished - 2009
Event2009 IEEE International Conference on Robotics and Automation, ICRA '09 - Kobe, Japan
Duration: 2009 May 122009 May 17

Publication series

NameProceedings - IEEE International Conference on Robotics and Automation
ISSN (Print)1050-4729


Other2009 IEEE International Conference on Robotics and Automation, ICRA '09

ASJC Scopus subject areas

  • Software
  • Control and Systems Engineering
  • Artificial Intelligence
  • Electrical and Electronic Engineering


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