Transcript Gait Transition

Zurich, 25 May 2004
Leg design and
control of locomotion
Andre Seyfarth
Hartmut Geyer
Fumiya Iida
Locomotion Lab Jena
Locomotion
Experiments
Neuromechanical
Models
Technical
Implementation
Gait Transitions
3D-instrumented
Treadmill
Gait specific control
templates
Legged Systems
Gait Orthesis
Locomotion
Experiments
Neuromechanical
Models
Technical
Implementation
Central hypothesis

To achieve periodic movement
patterns, an appropriate design
criterion is required.

In our approach, system stability is
such a criterion.
Stability requirements
Internal Leg Operation Global
Stability requirements
Internal Leg Operation


Segmentation
Control at Joint Level
Stability requirements
Global
Leg Operation



Running
Walking
Gait Transition
Part I
Internal
Leg Operation
Biologically Inspired Approach

In many task, the leg behavior
can be compared to a simple
mechanical spring.
Control of a segmented leg
Idea
Control of a segmented leg
Idea
Control of a segmented leg
Idea
Control of a segmented leg
Control of a segmented leg
Solutions
+
• Biarticular Structures (e.g. Muscles)
• Geometric Constraints (e.g. Heel pad)
Seyfarth et al. (2001) Biol. Cybern.
Control at Joint Level
Where does the
muscle activation for
periodic movements
come from?
Control at Joint Level
STIM(t)

Positive Force
Feedback
P(t)
Geyer et al. (2003) Proc.Roy.Soc.B.
Control at Joint Level
Part II
Global
Leg Operation
Control of Pedal Locomotion
stance phase
swing phase
axial
required
‘leg spring’
optional
bended leg
rotatory
optional
e.g. hip torque
required
protraction
retraction
energetic
stabilization
kinematic
stabilization
Running
Spring Mass Running
fixed angle
of attack
fixed leg
stiffness
Seyfarth et al. (2002) J. Biomechanics
Spring Mass Running
RETRACTION
Seyfarth et al. (2003) J. Exp. Biol.
Spring Mass Running
Running in Horizontal Plane
Running in Horizontal Plane
Gait Transition
Gait Transition
Gait Transition
Leg force (N)
Experimental Results
RUN
WALK
Leg compression (m)
Leg force (N)
RUN
WALK
time (samples)
Gait Transition
Experimental Results
Gait Transition
Experimental Results
Gait Transition
Experimental Results
Gait Transition
Max. Speed Inv. Pendulum
New Theory
Gait Transition
Experimental Results
Walking
Spring Mass Walking
Spring Mass Walking
Spring Mass Walking
Ground Reaction Forces
A
B
C
Part III
Implications
Link to Robotics
Origin of Movements
Neural
Program
?
Mechanical
Behavior
Link to Robotics
Tight-Control
Relaxed Control
Link to Robotics
Hard-Control
Link to Robotics
Contribution of back movements to locomotion?
Link to Robotics
Contribution of back movements to locomotion?
Link to Rehabilitation
Decentralized leg control during locomotion
 Elastic knee joint during stance phase?
Thank you!
Locomotion Lab
at Jena University