9. The MIT Leg Lab: From Robots to Rehab

10. State Of The Art Flex-Foot Otto Bock C-Leg

11. State of the Art: Prosthetist defines knee damping Otto Bock C-Leg

12. The MIT Knee: A Step Towards Autonomy Virtual Prosthetist Virtual Biomechanist

13. How The MIT Knee Works: Mechanism

14. How The MIT Knee Works: Sensors Knee Position Axial Force Bending Moment Measured Local to Knee Axis (no ankle or foot sensors) Amputee can use vertical shock system

15. Goal: Early Stance Flexion & Extension How the MIT Knee Works: Stance Control

16. Stance Control: Three States Stance Flexion & Stance Extension – A variable hydraulic damper – Damping scales with axial load Late Stance – Minimize damping Toe-Loading to trigger late-stance zero damping is automatically adjusted by system

17. Stance Flexion

18. Goal: Control Peak Flexion Angle & Terminal Impact How the MIT Knee Works: Swing Control

19. Swing Control: Flexion

21. Swing Phase: Extension Extension damping adaptation Stage one: – Map t c versus impact force – Apply appropriate damping Stage two: – Control final angle while minimizing impact force Foot Contact Time

22. The MIT Knee In Action

23. Human Knees Brake and Thrust 0 1 Power (W/Kg) Percent Gait Cycle

24. Human Ankles are Smart Springs Variable stiffness foot-ankle systems Leg stiffness control in walking and running humans

25. Human Ankles are Powered

26. Future of O&P Leg Systems: Intelligent Application of Power Greater Distance & Less Fatigue Natural Gait - Dynamic Cosmesis Enhanced Stability Increased Mobility

27. Human Rehab: A Road Map to the Future Better Power Systems and Actuators

28. Series-Elastic Actuators (Muscle-Tendon)

29. Controlling Force, not Position Weight: 2.5 lbs. Stroke: 3 in. Max. Force: 300 lbs. Force Bandwidth: 30 Hz

30. Nearly autonomous Controllable Swam 0.5 body length per second Biomechatronics Group Hybrid Robots

31. Human Rehab: A Road Map to the Future Improved Walking Models

32. Low Stiffness Control: Virtual Model Control Language Passive walkers work using physical components Q: Can active walker algorithms be expressed using physical metaphors? A: Yes, and they perform surprisingly well

33. Virtual Assistive Devices for Legged Robots

34. Troody

35. Science Technology What are the biological models for human walking? Virtual Model Control Active O&P Leg Systems

36. Human Rehab: A Road Map to the Future Distributed Sensing and Intelligence

37. Virtual Prosthetist Virtual Biomechanist User Intent

38. Collaborators Leg Laboratory Gill Pratt Biomechatronics Group Robert Dennis (UM) Nadia Rosenthal (MGH) Richard Marsh (NE) Spaulding Gait Laboratory Casey Kerrigan Pat Riley

39. Sponsors Össur DARPA Schaeffer Foundation

40. Summary Advances in the science of legged locomotion, bioactuation, and sensing are necessary to step towards the next generation of O&P leg systems