Development of a multiple axis robotic platform for ankle studies

Varun Nalam, Hyunglae Lee

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

2 Scopus citations


This paper describes the design, development, modeling, and control of a robotic platform developed for the characterization of mechanical impedance and reflex responses of the ankle in 2 degrees-of-freedom (DOF): sagittal (dorsiflexionplantarflexion) and frontal plane (inversion-eversion). The platform, controlled actively along both DOFs, is capable of producing rapid and strong perturbations up to an angular speed of 200°/s and peak torque of 400 Nm. This enables study of ankle impedance characteristics even during extreme task conditions such as running. The platform is designed to provide perturbations to the ankle up to an angle of 20° in sagittal plane and 10° in frontal plane, which is sufficient for all possible configurations of the ankle during postural balance and stance phase of walking. These characteristics of the platform make it ideal for both impedance and reflex characterization along both DOFs of the ankle. The platform's performance of position control is validated under varying loads simulating various conditions of posture and locomotion. The platform's orientation accuracy in both sagittal and frontal planes is established for various input signals including slow sinusoid inputs and rapid ramp perturbations. Implications for future ankle studies to estimate neuro-mechanical characteristics and applications to assistive and prosthetic devices are discussed.

Original languageEnglish (US)
Title of host publicationAdvances in Control Design Methods, Nonlinear and Optimal Control, Robotics, and Wind Energy Systems; Aerospace Applications; Assistive and Rehabilitation Robotics; Assistive Robotics; Battery and Oil and Gas Systems; Bioengineering Applications; Biomedical and Neural Systems Modeling, Diagnostics and Healthcare; Control and Monitoring of Vibratory Systems; Diagnostics and Detection; Energy Harvesting; Estimation and Identification; Fuel Cells/Energy Storage; Intelligent Transportation
PublisherAmerican Society of Mechanical Engineers
ISBN (Electronic)9780791850695
StatePublished - 2016
EventASME 2016 Dynamic Systems and Control Conference, DSCC 2016 - Minneapolis, United States
Duration: Oct 12 2016Oct 14 2016


OtherASME 2016 Dynamic Systems and Control Conference, DSCC 2016
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Mechanical Engineering


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