There's no need to re-invent the weel, so why try? You have a lot at your disposal, here:
Take the Geneva Movement, for example, a simple way to make a sudden movement, then a halt, then another sudden movement, etc., all that out of a simple, no-nags, electric motor.
(photo taken from the KMODL site, as you can see from the image's properties, go there, the home link's the one above)
So no need for a robot , where one of those mechanisms can do the trick... AND you'll never know how much you can learn from there, there's levers, worm wheels, gear wheels, pulleys, belt drives, anything to help you make from your garage's door mechanism, to a better mousetrap!