Variable stiffness actuated prosthetic knee to restore knee buckling during stance: a modeling study

Abstract

Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic behavior and use stored energy during flexion to assist in subsequent extension. A principle design of energy efficient VSA in a prosthetic knee is proposed and analyzed for the specific case of rejection of a disturbed stance phase. The concept is based on the principle that the output stiffness of a spring can be changed without changing the energy stored in the elastic elements of the spring. The usability of this concept to control a prosthetic knee is evaluated using a model. Part of the stance phase of the human leg was modeled by a double pendulum. Specifically the rejection of a common disturbance of transfemoral prosthetic gait, an unlocked knee at heel strike, was evaluated. The ranges of spring stiffnesses were determined such that the angular characteristics of a normal stance phase were preserved, but disturbances could also be rejected. The simulations predicted that energy efficient VSA can be useful for the control of prosthetic knees.
Original languageUndefined
Pages (from-to)838-845
Number of pages8
JournalMedical engineering & physics
Volume35
Issue number6
DOIs
StatePublished - Jun 2013

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Prosthetics
Knee
Stiffness
Knee prostheses
Pendulums
Energy utilization
Knee Prosthesis
Heel
Gait
Leg

Keywords

  • BSS-Biomechatronics and rehabilitation technology
  • EWI-22608
  • Transfemoral prosthesisVariable stiffness actuationVSAProsthetic kneeEnergy efficient

Cite this

@article{fd53f5978b9944beaa61cbb6727f7991,
title = "Variable stiffness actuated prosthetic knee to restore knee buckling during stance: a modeling study",
abstract = "Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic behavior and use stored energy during flexion to assist in subsequent extension. A principle design of energy efficient VSA in a prosthetic knee is proposed and analyzed for the specific case of rejection of a disturbed stance phase. The concept is based on the principle that the output stiffness of a spring can be changed without changing the energy stored in the elastic elements of the spring. The usability of this concept to control a prosthetic knee is evaluated using a model. Part of the stance phase of the human leg was modeled by a double pendulum. Specifically the rejection of a common disturbance of transfemoral prosthetic gait, an unlocked knee at heel strike, was evaluated. The ranges of spring stiffnesses were determined such that the angular characteristics of a normal stance phase were preserved, but disturbances could also be rejected. The simulations predicted that energy efficient VSA can be useful for the control of prosthetic knees.",
keywords = "BSS-Biomechatronics and rehabilitation technology, EWI-22608, Transfemoral prosthesisVariable stiffness actuationVSAProsthetic kneeEnergy efficient",
author = "E.C. Wentink and Koopman, {Hubertus F.J.M.} and Stefano Stramigioli and Rietman, {Johan Swanik} and Veltink, {Petrus H.}",
year = "2013",
month = "6",
doi = "10.1016/j.medengphy.2012.08.016",
volume = "35",
pages = "838--845",
journal = "Medical engineering & physics",
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publisher = "Elsevier BV",
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T1 - Variable stiffness actuated prosthetic knee to restore knee buckling during stance: a modeling study

AU - Wentink,E.C.

AU - Koopman,Hubertus F.J.M.

AU - Stramigioli,Stefano

AU - Rietman,Johan Swanik

AU - Veltink,Petrus H.

PY - 2013/6

Y1 - 2013/6

N2 - Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic behavior and use stored energy during flexion to assist in subsequent extension. A principle design of energy efficient VSA in a prosthetic knee is proposed and analyzed for the specific case of rejection of a disturbed stance phase. The concept is based on the principle that the output stiffness of a spring can be changed without changing the energy stored in the elastic elements of the spring. The usability of this concept to control a prosthetic knee is evaluated using a model. Part of the stance phase of the human leg was modeled by a double pendulum. Specifically the rejection of a common disturbance of transfemoral prosthetic gait, an unlocked knee at heel strike, was evaluated. The ranges of spring stiffnesses were determined such that the angular characteristics of a normal stance phase were preserved, but disturbances could also be rejected. The simulations predicted that energy efficient VSA can be useful for the control of prosthetic knees.

AB - Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic behavior and use stored energy during flexion to assist in subsequent extension. A principle design of energy efficient VSA in a prosthetic knee is proposed and analyzed for the specific case of rejection of a disturbed stance phase. The concept is based on the principle that the output stiffness of a spring can be changed without changing the energy stored in the elastic elements of the spring. The usability of this concept to control a prosthetic knee is evaluated using a model. Part of the stance phase of the human leg was modeled by a double pendulum. Specifically the rejection of a common disturbance of transfemoral prosthetic gait, an unlocked knee at heel strike, was evaluated. The ranges of spring stiffnesses were determined such that the angular characteristics of a normal stance phase were preserved, but disturbances could also be rejected. The simulations predicted that energy efficient VSA can be useful for the control of prosthetic knees.

KW - BSS-Biomechatronics and rehabilitation technology

KW - EWI-22608

KW - Transfemoral prosthesisVariable stiffness actuationVSAProsthetic kneeEnergy efficient

U2 - 10.1016/j.medengphy.2012.08.016

DO - 10.1016/j.medengphy.2012.08.016

M3 - Article

VL - 35

SP - 838

EP - 845

JO - Medical engineering & physics

T2 - Medical engineering & physics

JF - Medical engineering & physics

SN - 1350-4533

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