A robotic apparatus that dictates torque fields around joints without affecting inherent joint dynamics

Yalchin Oytam, David Lloyd, Campbell S Reid, Aymar de Rugy, Richard G Carson

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


This manuscript describes how motor behaviour researchers who are not at the same time expert roboticists may implement an experimental apparatus, which has the ability to dictate torque fields around a single joint on one limb or single joints on multiple limbs without otherwise interfering with the inherent dynamics of those joints. Such an apparatus expands the exploratory potential of the researcher wherever experimental distinction of factors may necessitate independent control of torque fields around multiple limbs, or the shaping of torque fields of a given joint independently of its plane of motion, or its directional phase within that plane. The apparatus utilizes torque motors. The challenge with torque motors is that they impose added inertia on limbs and thus attenuate joint dynamics. We eliminated this attenuation by establishing an accurate mathematical model of the robotic device using the Box-Jenkins method, and cancelling out its dynamics by employing the inverse of the model as a compensating controller. A direct measure of the remnant inertial torque as experienced by the hand during a 50 s period of wrist oscillations that increased gradually in frequency from 1.0 to 3.8 Hz confirmed that the removal of the inertial effect of the motor was effectively complete.
Original languageEnglish
Pages (from-to)701-12
Number of pages12
JournalHuman Movement Science
Issue number5
Publication statusPublished - Oct 2010

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Biophysics
  • Experimental and Cognitive Psychology


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