Energetic Passivity of the Human Ankle Joint

Hyunglae Lee, Neville Hogan

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Understanding the passive or nonpassive behavior of the neuromuscular system is important to design and control robots that physically interact with humans, since it provides quantitative information to secure coupled stability while maximizing performance. This has become more important than ever apace with the increasing demand for robotic technologies in neurorehabilitation. This paper presents a quantitative characterization of passive and nonpassive behavior of the ankle of young healthy subjects, which provides a baseline for future studies in persons with neurological impairments and information for future developments of rehabilitation robots, such as exoskeletal devices and powered prostheses. Measurements using a wearable ankle robot actuating 2 degrees-of-freedom of the ankle combined with curl analysis and passivity analysis enabled characterization of both quasi-static and steady-state dynamic behavior of the ankle, unavailable from single DOF studies. Despite active neuromuscular control over a wide range of muscle activation, in young healthy subjects passive or dissipative ankle behavior predominated.

Original languageEnglish (US)
Article number7430364
Pages (from-to)1416-1425
Number of pages10
JournalIEEE Transactions on Neural Systems and Rehabilitation Engineering
Issue number12
StatePublished - Dec 2016


  • Dissipativity
  • human ankle dynamics
  • joint mechanical impedance
  • passivity
  • physical human-robot interaction

ASJC Scopus subject areas

  • Rehabilitation
  • General Neuroscience
  • Internal Medicine
  • Biomedical Engineering


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