Powered ankle-foot prosthesis for the improvement of amputee walking economy

The human ankle provides a significant amount of net positive work during the stance period of walking, especially at moderate to fast walking speeds. On the contrary, conventional ankle-foot prostheses are completely passive during stance, and consequently, cannot provide net positive work. Clinical studies indicate that transtibial amputees using conventional prostheses exhibit higher gait metabolic rates as compared to intact individuals. Researchers believe the main cause for the observed increase in metabolism is due to the inability of conventional prostheses to provide net positive work at terminal stance in walking. This objective of this thesis is to evaluate the hypothesis that a powered anklefoot prosthesis, capable of providing active mechanical power at terminal stance, can improve amputee metabolic walking economy compared to a conventional passiveelastic prosthesis. To test the hypothesis, a powered prosthesis is designed and buil that comprises a unidirectional spring, configured in parallel with a force-controllable actuator with series elasticity. The prosthesis is controlled to mimick human ankle walking behavior, in particular, the power generation characteristics observed in normal human walking. The rate of oxygen consumption is measured as a determinant of metabolic rate on three unilateral transtibial amputees walking at self-selected speeds. The initial clinical evaluation shows that the powered prosthesis improves amputee metabolic economy from 7% to 20% compared to the conventional passive-elastic prostheses (Flex-Foot Ceterus and Freedom Innovations Sierra), even though the powered system is twofold heavier than the conventional devices. These results support the proposed hypothesis and also suggest a promising direction for further advancement of anklefoot prosthesis. Thesis Supervisor: Hugh Herr Title: Associate Professor of Media Arts and Sciences Assistant Professor of MIT-Harvard Division of Health Science and Technology

[1]  R.D. Lorenz,et al.  Experimental identification of friction and its compensation in precise, position controlled mechanisms , 1991, Conference Record of the 1991 IEEE Industry Applications Society Annual Meeting.

[2]  David W. Robinson,et al.  Design and analysis of series elasticity in closed-loop actuator force control , 2000 .

[3]  R. Waters,et al.  Energy cost of walking of amputees: the influence of level of amputation. , 1976, The Journal of bone and joint surgery. American volume.

[4]  Hugh M. Herr,et al.  The effect of series elasticity on actuator power and work output: Implications for robotic and prosthetic joint design , 2006, Robotics Auton. Syst..

[5]  D. Herring,et al.  Adjustable Robotic Tendon using a ‘ Jack Spring ’ TM , 2005 .

[6]  K. Koyanagi,et al.  Research and Development of the Intelligently-Controlled Prosthetic Ankle Joint , 2006, 2006 International Conference on Mechatronics and Automation.

[7]  J Perry,et al.  Efficiency of dynamic elastic response prosthetic feet. , 1993, Journal of rehabilitation research and development.

[8]  S.K. Au,et al.  Biomechanical Design of a Powered Ankle-Foot Prosthesis , 2007, 2007 IEEE 10th International Conference on Rehabilitation Robotics.

[9]  N. Hogan,et al.  Impedance and Interaction Control , 2018 .

[10]  R. Riener,et al.  Stair ascent and descent at different inclinations. , 2002, Gait & posture.

[11]  D. Barth,et al.  Gait Analysis and Energy Cost of Below‐Knee Amputees Wearing Six Different Prosthetic Feet , 1992 .

[12]  Donald G. Shurr,et al.  Gait Comparisons for Below-Knee Amputees Using a Flex-Foot™ Versus a Conventional Prosthetic Foot , 1991 .

[13]  R. Seymour.  Prosthetics and orthotics : lower limb and spinal , 2002 .

[14]  M. Pandy,et al.  Dynamic optimization of human walking. , 2001, Journal of biomechanical engineering.

[15]  C. Hausswirth,et al.  The Cosmed K4 Telemetry System as an Accurate Device for Oxygen Uptake Measurements during Exercise , 1997, International journal of sports medicine.

[16]  S. Gard,et al.  The human ankle during walking: implications for design of biomimetic ankle prostheses. , 2004, Journal of biomechanics.

[17]  Peggy Arnell,et al.  The Biomechanics and Motor Control of Human Gait , 1988 .

[18]  A. Ruina,et al.  A collisional model of the energetic cost of support work qualitatively explains leg sequencing in walking and galloping, pseudo-elastic leg behavior in running and the walk-to-run transition. , 2005, Journal of theoretical biology.

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

[20]  J. van den Berg,et al.  Calf muscle moment, work and efficiency in level walking; role of series elasticity. , 1983, Journal of biomechanics.

[21]  D. Winter,et al.  Biomechanics of below-knee amputee gait. , 1988, Journal of biomechanics.

[22]  J. Donelan,et al.  Mechanical work for step-to-step transitions is a major determinant of the metabolic cost of human walking. , 2002, The Journal of experimental biology.

[23]  N. Hogan,et al.  Impedance Control:An Approach to Manipulation,Parts I,II,III , 1985 .

[24]  D. Shurr,et al.  Comparison of Energy Cost and Gait Efficiency During Ambulation in Below-Knee Amputees Using Different Prosthetic Feet—A Preliminary Report , 1988 .

[25]  D. Winter.  Energy generation and absorption at the ankle and knee during fast, natural, and slow cadences. , 1983, Clinical orthopaedics and related research.

[26]  J. Didier,et al.  Bioenergetic comparison of a new energy-storing foot and SACH foot in traumatic below-knee vascular amputations. , 1995, Archives of physical medicine and rehabilitation.

[27]  Hugh M. Herr,et al.  An ankle-foot emulation system for the study of human walking biomechanics , 2006, Proceedings 2006 IEEE International Conference on Robotics and Automation, 2006. ICRA 2006..

[28]  D. Winter,et al.  An integrated biomechanical analysis of normal stair ascent and descent. , 1988, Journal of biomechanics.

[29]  Warren P. Seering,et al.  On the Drive Systems for High-Performance Machines , 1984 .

[30]  T. Takenaka,et al.  The development of Honda humanoid robot , 1998, Proceedings. 1998 IEEE International Conference on Robotics and Automation (Cat. No.98CH36146).

[31]  Reinhard Blickhan,et al.  Positive force feedback in bouncing gaits? , 2003, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[32]  Conor James Walsh,et al.  Biomimetic Design of an Under-Actuated Leg Exoskeleton for Load-Carrying Augmentation , 2006 .

[33]  Ari Wilkenfeld,et al.  Biologically inspired autoadaptive control of a knee prosthesis , 2000 .

[34]  H. Skinner,et al.  Gait analysis in amputees. , 1985, American journal of physical medicine.

[35]  A. Kuo.  A simple model of bipedal walking predicts the preferred speed-step length relationship. , 2001, Journal of biomechanical engineering.

[36]  Gerhard Schweitzer,et al.  Finite-state control of a trans-femoral (TF) prosthesis , 2002, IEEE Trans. Control. Syst. Technol..

[37]  Sandra J. Olney,et al.  Kinematic and Kinetic Variations of Below-Knee Amputee Gait , 2002 .

[38]  S. Simon.  Gait Analysis, Normal and Pathological Function. , 1993 .

[39]  G K Klute,et al.  Mechanical properties of prosthetic limbs: adapting to the patient. , 2001, Journal of rehabilitation research and development.

[40]  Warren P. Seering,et al.  Three dynamic problems in robot force control , 1992, IEEE Trans. Robotics Autom..

[41]  Matthew M. Williamson,et al.  Series elastic actuators , 1995, Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots.

[42]  Blake Hannaford,et al.  Development of Powered Prosthetic Lower Limb , 1998 .

[43]  Donald Lee Grimes.  An active multi-mode above knee prosthesis controller , 1979 .

[44]  Michael Lars Palmer,et al.  Sagittal plane characterization of normal human ankle function across a range of walking gait speeds , 2002 .

[45]  R. B. Davis,et al.  Gait characterization via dynamic joint stiffness , 1996 .

[46]  T. McMahon,et al.  Ballistic walking. , 1980, Journal of biomechanics.

[47]  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.

[48]  Arthur D Kuo,et al.  Energetics of actively powered locomotion using the simplest walking model. , 2002, Journal of biomechanical engineering.

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

[50]  J. Donelan,et al.  Mechanics and energetics of swinging the human leg , 2005, Journal of Experimental Biology.

[51]  S. Naumann,et al.  ANALYSIS OF MECHANICAL AND METABOLIC FACTORS IN THE GAIT OF CONGENITAL BELOW KNEE AMPUTEES: A Comparison of the SACH and Seattle Feet , 1992, American journal of physical medicine & rehabilitation.

[52]  Fumio Kanehiro,et al.  Humanoid robot HRP-2 , 2008, IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA '04. 2004.

[53]  J. Brockway.  Derivation of formulae used to calculate energy expenditure in man. , 1987, Human nutrition. Clinical nutrition.

[54]  Andy Ruina,et al.  Energetic Consequences of Walking Like an Inverted Pendulum: Step-to-Step Transitions , 2005, Exercise and sport sciences reviews.

[55]  N. H. Molen.  Energy/speed relation of below-knee amputees walking on a motor-driven treadmill , 1973, Internationale Zeitschrift für angewandte Physiologie einschließlich Arbeitsphysiologie.