Gait Ankle¶

Notes from Kristján.¶

Phases from the prespective of the ankle¶

• Initial contact
  • Neutral (90°), slight dorsiflexion. Preparing for response.
• Loading response
  • Plantar flexion (10°). Function: Shock response.
• Mid stance
  • Dorsiflexion (from 8° plantarflex to 5° dorsiflex). Function: Allow forward progression of tibia.
• Terminal stance
  • Heel rise (doriflexion up to 10°)
• Pre-swing
  • Plantar-flexion (20°). Function: Initiate knee flexion for swing.
• <Missing> (I actually missed what the guy said here, if anyone has it please edit the file and add it.)
  • Slight dorsiflexion in the ankle to prepare hitting the ground again.

Ankle design ideas¶

• Flexible sole
• Hinge joint motorized
  • Possible second axis of swivel
• Springs or elastic for "natural" shock absorption
• Motor for natural push off
• Possibilities for more gait types than heel to toe roll

Image sketch¶

Calculations results.
The ankle at 10° with a 120 kg load gets a 294.3 Nm.
So the ankle needs to handle that kinda tourqe