I also have been working on animating robots lately too. Now the two ideas are coming together. At first I started thinking about making a portrait then trying to make it move through redrawing it in stages using the Brushes App. You can see below that I redrew the eyes by moving the irises and making them blink. These drawn, saved as steps, and complied in EZGIF.com to make an animated GIF.
I loaded the Keynote drawing into the Photoshop Fix app and saved it (just in case the format changed. All images have to have the exact sizes to blend nicely as a GIF.
This is where I can adjust the speed, crop, and duplicate frames to customize the GIF.
When I first started trying to animate my portrait I was using the Brushes app to redraw only the eyes. I thought it would be the most effective and easy feature to move in a portrait. So, I erased and redrew each stage of this animation, saved it to the camera roll and used EZGIF to make the animation.