The articulation is serially stacked. The “foot bone is connected to the leg bone” sort of thing. In this case, the face is articulated, and the eye and eyelids are articulated relative to the face.
Why do this? Because the axis of rotation for the face and eyelids is at the same place for all, and therefore, tightly nested spherical features won’t collide.
Main Body is connected to the Face Pan Post
Face Pan Post is connected to Face Roll/Tilt Gimbal
Face Roll/Tilt Gimbal has a dead axle that supports Face Tilt and Eyelids. It also supports the Eyelid motors and Eye Pan motor.
Face Tilt is connected to the Eye Pan, and also supports the Eye Tilt motor.
Eye Pan is connected to the Main Eye, in this case an oLED 128×128 pixel display.
It’s great what you are doing, but can you please upload somewhere the Wheatley 3d model? I want to build it also but I am very bad at 3d modeling and I want to 3d print the pieces.