COMpliant huMANoid COMAN: Optimal joint stiffness tuning for modal frequency control

N. G. Tsagarakis, S. Morfey, G. Medrano Cerda, Zhibin Li, D. G. Caldwell

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


The incorporation of passive compliance in robotic systems could improve their performance during interactions and impacts, for energy storage and efficiency, and for general safety for both the robots and humans. This paper presents the recently developed COMpliant huMANoid COMAN. COMAN is actuated by passive compliance actuators based on the series elastic actuation principle (SEA). The design and implementation of the overall body of the robot is discussed including the realization of the different body segments and the tuning of the joint distributed passive elasticity. This joint stiffness tuning is a critical parameter in the performance of compliant systems. A novel systematic method to optimally tune the joint elasticity of multi-dof SEA robots based on resonance analysis and energy storage maximization criteria forms one of the key contributions of this work. The paper will show this method being applied to the selection of the passive elasticity of COMAN legs. The first completed robot prototype is presented accompanied by experimental walking trials to demonstrate its operation.
Original languageEnglish
Title of host publicationRobotics and Automation (ICRA), 2013 IEEE International Conference on
Number of pages6
Publication statusPublished - 1 May 2013


  • compliance control
  • compliant mechanisms
  • elasticity
  • frequency control
  • gait analysis
  • humanoid robots
  • legged locomotion
  • resonance
  • robot dynamics
  • COMAN legs
  • body segments
  • compliant humanoid
  • compliant system performance improvement
  • energy efficiency
  • energy storage
  • energy storage maximization criteria
  • human safety
  • joint distributed passive elasticity tuning
  • modal frequency control
  • multiDoF SEA robots
  • optimal joint stiffness tuning
  • passive compliance actuators
  • resonance analysis
  • robot prototype
  • robot safety
  • robotic systems
  • series elastic actuation principle
  • walking trials
  • Elasticity
  • Hip
  • Joints
  • Legged locomotion
  • Resonant frequency
  • Torque

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