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Muscle-Reflex Model That Encodes Principlesof Legged Mechanics Produces Human Walk-
ingDynamics and Muscle Activities
서울대학교이경호
2012. 4. 06
Introduction
• Central Pattern Generator(CPG)– complex network of neurons that con-
trols legged locomotion of animals and humans.
– in spinal cord
Introduction
• Principle of legged mechanics– it can largely simplify locomotion control– self-stability, compliant leg behavior
• How these principles integrated into human motor control?– spinal reflexes– they can link sensory information into
activation of the leg muscles
Human Model
SOL : soleus
VAS : vasti
GAS : gastrocnemius
TA : tibialis anterior
GLU : gluteal muscles
HFL : hip flexor muscles
HAM : hamstring
Muscle-tendon model
Muscle Control
• positive force feedback (F+)
S : stimulationS0 : prestimulationG : GainF : force△t : time delay
Muscle-tendon model
A : muscle activationfl : force-length relationshipfv : force-velocity relation-ship
Human Model
SOL : soleus
VAS : vasti
GAS : gastrocnemius
TA : tibialis anterior
GLU : gluteal muscles
HFL : hip flexor muscles
HAM : hamstring
Muscle Control
• positive length feedback (L+)
Human Model
SOL : soleus
VAS : vasti
GAS : gastrocnemius
TA : tibialis anterior
GLU : gluteal muscles
HFL : hip flexor muscles
HAM : hamstring
Muscle Control
• PD control
kp, kd : gain : reference lean an-gle
Double Support
Actual Leg Swing Phase
During actual swing, we mainly rely on a leg’s ballistic motion. The dis-tal leg muscles SOL, GAS, and VAS are silent in that phase. Only TA’s L+, remains active to provide foot clearance with the ground
Pattern Generation
Result
• Walking Gait
- Matlab SimMechan-ics
GRF : ground reaction force
Result
• Predict Motor Output
Result
• Adaptation to Slopes
Discussion
• Principles of legged mechanics ex-plains the basic dynamics of human locomotion– encode several principles of legged me-
chanics with actuators and control, which turned into muscles and reflexes
• Is it sufficient?–more principles of legged mechanics do
certainly exist– level of detail
Discussion
• CPG vs Reflex– Actual ratio of central and reflex inputs
is remain uncelar