Android 12 Ankle and foot assembly.
This page is about Android 12’s ankle and shin assembly, check out the project index for the rest.
As with the foot, all of the parts will be 3D printed, so my initial work is to design the pieces in CAD. I’m using Autodesk 123D, which is free software. There are some YouTube videos for this section, or scroll down for pictures and words.
Here are the initial pictures of the ankle joint assembly. The majority of the Android from this part up will be modular and designed to fit around lengths of studding so adjustments can be made in the spacing of the pieces:
Here’s the shin/calf actuator part which will hold a servo, this part is also attached to the studding:
I designed this hinge piece which attaches to the shock absorbers and the shin assembly. This piece will also be attached to the servo with another spring, so that the hinge plate is held tight against the shin as the Achilles tendon is released, and allowed to hinge outwards as the Achilles is pulled tight. This means that the shock absorber takes the weight of the android leaning forward during motion instead of the servo:
Here’s a custom servo horn extension I made because the servos don’t ship with a horn that’s round or right angled, but I need motion in both directions to operate the Achilles and the hinged part that’s linked to the shocks:
Pictures of the completed ankle and shin assembly:
Testing video at the top of the page.