A Variable Impedance Knee Mechanism for Controlled Stance Flexion During Pathological Gait

A variable impedance knee mechanism (VIKM) has been developed as an orthotic intervention for individuals with weakened or paralyzed knee extensors. The purpose of the VIKM is to substitute for the function of eccentric quadriceps contraction to allow controlled levels of knee flexion during stance phase of gait and stair descent. The design concept, mechanism optimization, fabrication, bench testing, and initial results from walking tests with an able-bodied subject are reported. The VIKM utilizes a linear magnetorheological (MR) fluid damper with a four-bar linkage transmission to provide controllable resistance to knee motion. The design of the linkage enables the VIKM to provide large torques to resist motion at any knee angle. The prototype VIKM and full leg orthosis weigh 3.50 kg. The VIKM can provide a maximum of 64.5 N·m of torque in 35 ms. The average passive resistance is less than 4 N·m at an angular velocity of 210°/s. The ability of the VIKM to lock against knee flexion and allow knee motion under high loading is also demonstrated. Future work will focus on the development of a closed loop control system to automatically adjust the resistance level of the VIKM during walking and on clinical evaluation of the VIKM in pathological gait.

[1]  Andy Ruina,et al.  A Bipedal Walking Robot with Efficient and Human-Like Gait , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[2]  M. Goldfarb,et al.  Preliminary evaluation of a controlled-brake orthosis for FES-aided gait , 2003, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[3]  H.A. Varol,et al.  Preliminary Evaluations of a Self-Contained Anthropomorphic Transfemoral Prosthesis , 2009, IEEE/ASME Transactions on Mechatronics.

[4]  R. Kobetic,et al.  Design of a Variable Constraint Hip Mechanism for a Hybrid Neuroprosthesis to Restore Gait After Spinal Cord Injury , 2008, IEEE/ASME Transactions on Mechatronics.

[5]  Denny J. Padgett,et al.  Gait and balance of transfemoral amputees using passive mechanical and microprocessor-controlled prosthetic knees. , 2007, Gait & posture.

[6]  Edward D Lemaire,et al.  Engineering design review of stance-control knee-ankle-foot orthoses. , 2009, Journal of rehabilitation research and development.

[7]  F Freudenstein,et al.  Kinematics of the human knee joint. , 1969, The Bulletin of mathematical biophysics.

[8]  Hugh Herr,et al.  User-adaptive control of a magnetorheological prosthetic knee , 2003, Ind. Robot.

[9]  R. Waters,et al.  Energy cost of paraplegic locomotion. , 1985, The Journal of bone and joint surgery. American volume.

[10]  H. Herr,et al.  A Clinical Comparison of Variable-Damping and Mechanically Passive Prosthetic Knee Devices , 2005, American journal of physical medicine & rehabilitation.

[11]  J. Michael,et al.  Design Principles, Biomeclianical Data and Clinical Experience with a Polycentric Knee Offering Controlled Stance Phase Knee Flexion: A Preliminary Report , 1997 .

[12]  T. Andriacchi,et al.  A study of lower-limb mechanics during stair-climbing. , 1980, The Journal of bone and joint surgery. American volume.

[13]  B. J. Mcfayden.  An Integrated Biomechanical Analysis of Normal Stair Ascent and Descent , 1988 .

[14]  R. Triolo,et al.  Effects of spinal cord injury on lower-limb passive joint moments revealed through a nonlinear viscoelastic model. , 2004, Journal of rehabilitation research and development.

[15]  K R Kaufman,et al.  Optimization and application of a wrap-spring clutch to a dynamic knee-ankle-foot orthosis. , 1999, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[16]  H. Herr,et al.  Adaptive control of a variable-impedance ankle-foot orthosis to assist drop-foot gait , 2004, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[17]  J. Carlson,et al.  MR fluid, foam and elastomer devices , 2000 .

[18]  Scott Tashman,et al.  Development of hybrid orthosis for standing, walking, and stair climbing after spinal cord injury. , 2009, Journal of rehabilitation research and development.

[19]  C W Radcliffe.  Four-bar linkage prosthetic knee mechanisms: Kinematics, alignment and prescription criteria , 1994, Prosthetics and orthotics international.

[20]  M. Goldfarb,et al.  Design of a Multidisc Electromechanical Brake , 2011, IEEE/ASME Transactions on Mechatronics.

[21]  Shirley J. Dyke,et al.  PHENOMENOLOGICAL MODEL FOR MAGNETORHEOLOGICAL DAMPERS , 1997 .

[22]  Constantinos Mavroidis,et al.  Smart Portable Rehabilitation Devices , 2005 .

[23]  Wei-Hsin Liao,et al.  Design, testing and control of a magnetorheological actuator for assistive knee braces , 2010 .

[24]  B. Heller,et al.  A new hybrid spring brake orthosis for controlling hip and knee flexion in the swing phase , 2001, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[25]  Richard A. Brand,et al.  The biomechanics and motor control of human gait: Normal, elderly, and pathological , 1992 .

[26]  Constantinos Mavroidis,et al.  Control of electro-rheological fluid based resistive torque elements for use in active rehabilitation devices , 2007 .

[27]  O. Kameyama,et al.  Newly designed computer controlled knee-ankle-foot orthosis (Intelligent Orthosis) , 1998, Prosthetics and orthotics international.

[28]  W D Spence,et al.  Energy cost of walking: comparison of "intelligent prosthesis" with conventional mechanism. , 1997, Archives of physical medicine and rehabilitation.

[29]  G. Obinata,et al.  An electrical knee lock system for functional electrical stimulation. , 1996, Archives of physical medicine and rehabilitation.

[30]  S. Tashman,et al.  The Case Western Reserve University Hybrid Gait Orthosis , 2000, The journal of spinal cord medicine.

[31]  E. Marsolais,et al.  Synthesis of paraplegic gait with multichannel functional neuromuscular stimulation , 1994 .

[32]  J. David Carlson,et al.  Smart prosthetics based on magnetorheological fluids , 2001, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[33]  J. Carlson,et al.  A model of the behaviour of magnetorheological materials , 1996 .

[34]  Tao Geng,et al.  Planar Biped Walking With an Equilibrium Point Controller and State Machines , 2010, IEEE/ASME Transactions on Mechatronics.

[35]  Alfred D. Grant.  Gait Analysis: Normal and Pathological Function , 2010 .

[36]  Shufang Dong,et al.  Rehabilitation device with variable resistance and intelligent control. , 2005, Medical engineering & physics.

[37]  Michael Goldfarb,et al.  Design of a joint-coupled orthosis for FES-aided gait , 2009, 2009 IEEE International Conference on Rehabilitation Robotics.

[38]  J. Michael,et al.  Preliminary Evidence for Effectiveness of a Stance Control Orthosis , 2004 .

[39]  J. Kofman,et al.  Design and Evaluation of a Stance-Control Knee-Ankle-Foot Orthosis Knee Joint , 2006, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[40]  Shyamal Patel,et al.  Design, Control and Human Testing of an Active Knee Rehabilitation Orthotic Device , 2007, Proceedings 2007 IEEE International Conference on Robotics and Automation.

[41]  M Goldfarb,et al.  Design of a controlled-brake orthosis for FES-aided gait. , 1996, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[42]  Gregory N. Washington,et al.  A magnetorheological fluid-based controllable active knee brace , 2007, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[43]  M. Granat,et al.  A knee and ankle flexing hybrid orthosis for paraplegic ambulation. , 2003, Medical engineering & physics.

[44]  Hans Conrad,et al.  An analytical model for magnetorheological fluids , 2000 .