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

Updated by Sæþór Ólafur Pétursson over 11 years ago · 7 revisions