1. Andre Seyfarth Hartmut Geyer Fumiya Iida Leg design and control of locomotion Zurich, 25 May 2004 Locomotion Lab Jena

2. Locomotion Experiments Neuromechanical Models Technical Implementation Gait Transitions 3D-instrumented Treadmill Gait specific control templates Legged Systems Gait Orthesis

3. Locomotion Experiments Neuromechanical Models Technical Implementation

4. Central hypothesis To achieve periodic movement patterns, an appropriate design criterion is required. To achieve periodic movement patterns, an appropriate design criterion is required. In our approach, system stability is such a criterion. In our approach, system stability is such a criterion.

5. Stability requirements InternalGlobalLeg Operation

6. Stability requirements InternalLeg Operation Segmentation Segmentation Control at Joint Level Control at Joint Level

7. Stability requirements GlobalLeg Operation Running Running Walking Walking Gait Transition Gait Transition

8. Part I Internal Leg Operation Internal Leg Operation

9. Biologically Inspired Approach In many task, the leg behavior can be compared to a simple mechanical spring. In many task, the leg behavior can be compared to a simple mechanical spring.

10. Control of a segmented leg Idea

11. Control of a segmented leg Idea

12. Control of a segmented leg Idea

13. Control of a segmented leg

14. Solutions Seyfarth et al. (2001) Biol. Cybern. Biarticular Structures (e.g. Muscles) Geometric Constraints (e.g. Heel pad) +

15. Control at Joint Level Where does the muscle activation for periodic movements come from?

16. Control at Joint Level  P(t) STIM(t) Geyer et al. (2003) Proc.Roy.Soc.B. Positive Force Feedback

17. Control at Joint Level

18. Part II Global Leg Operation

19. Control of Pedal Locomotion stance phaseswing phase axialrequiredoptional ‘leg spring’bended leg rotatoryoptionalrequired e.g. hip torque protraction retraction energetic stabilization kinematic stabilization

20. Running

21. Spring Mass Running fixed angle of attack fixed leg stiffness Seyfarth et al. (2002) J. Biomechanics

22. Spring Mass Running RETRACTION Seyfarth et al. (2003) J. Exp. Biol.

23. Spring Mass Running

24. Running in Horizontal Plane

26. Gait Transition

28. Leg force (N) time (samples) Leg compression (m) WALK RUN WALK Experimental Results

29. Gait Transition Experimental Results

30. Gait Transition Experimental Results

31. Gait Transition Experimental Results

32. Gait Transition New Theory Max. Speed Inv. Pendulum

33. Gait Transition Experimental Results

34. Walking

35. Spring Mass Walking

37. ABC Ground Reaction Forces

38. Part III Implications

39. Link to Robotics Origin of Movements Neural Program Mechanical Behavior ?

40. Link to Robotics Tight-ControlRelaxed Control

41. Link to Robotics Hard-Control

42. Link to Robotics Contribution of back movements to locomotion?

43. Link to Robotics Contribution of back movements to locomotion?

44. Link to Rehabilitation Decentralized leg control during locomotion  Elastic knee joint during stance phase?

45. Thank you! Locomotion Lab at Jena University