Powered ankle-foot prothesis

• US 20110257764A1
• Filed: 06/12/2008
• Published: 10/20/2011
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Deffenbaugh, Bruce Wayne, Aisen, Benjamin B., Au, Samuel K., Weber, Jeff A., Hoffman, Andreas G., Magnusson, Lee Harris, Herr, Hugh M.
• Granted Patent: US 8,512,415 B2
• Time in Patent Office: Days
• US Class Current: 623/24
• CPC Class Codes: A61F 2/60 Artificial legs or feet or parts thereof
• CPC Class Codes: A61F 2/605 Hip joints
• CPC Class Codes: A61F 2/64 Knee joints
• CPC Class Codes: A61F 2/6607 Ankle joints
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2002/5004 operated by electro- or magnetorheological fluids
• CPC Class Codes: A61F 2002/503 for adjusting elasticity, flexibility, spring rate or mechanical tension
• CPC Class Codes: A61F 2002/5033 for adjusting damping damping means A61F2002/5003
• CPC Class Codes: A61F 2002/5075 Multiple spring systems including two or more helical springs
• CPC Class Codes: A61F 2002/6818 for braking
• CPC Class Codes: A61F 2002/701 operated by electrically controlled means, e.g. solenoids or torque motors
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2002/7625 for measuring angular position
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2002/764 for measuring acceleration
• CPC Class Codes: A61F 2002/7645 for measuring torque, e.g. hinge or turning moment, moment of force
• CPC Class Codes: B25J 19/0008 Balancing devices

Abstract

A powered ankle-foot prosthesis, capable of providing human-like power at terminal stance that increase amputees metabolic walking economy compared to a conventional passive-elastic prosthesis. The powered prosthesis comprises a unidirectional spring, configured in parallel with a force-controllable actuator with series elasticity. The prosthesis is controlled to deliver the high mechanical power and net positive work observed in normal human walking.

Claims

1. A foot and ankle structure coupled for rotation with respect to a shin member at an ankle joint, said foot and ankle structure comprising:

A controllable actuator comprising a motor and a series spring connected to impart rotary motion to said foot and ankle structure about said ankle joint, and

a physical spring connected in parallel with said actuator that provides an offset stiffness only when said foot and ankle structure is positioned within a predetermined range of angles with respect to said shin member.