Well, unfortunately I have to go back to the drawing board for my robot, Nina. The Base I built for her was good, but she was getting to be a big girl (30 lbs +) and there was no way two 12V windshield wiper motors were going to move her.
Now for the good news. I happen to have a pair to two wheelchair motors that are in good condition in my garage. They're 24 Volt, but will run only on 12 volts which is just fine. Problem: I don't know how I'm going to mount them to the new base I'm building for my robot. There don't appear to be mounting screws or anything, just this weird clamp that looks like it clamps onto a curved L-shaped round bar of some sort, which I presume is meant for a wheelchair.
I'd send a picture of what it looks like, but don't know what to paste between the two image brackets in the text of this message (a web link? A directory on my PC?).
If anyone has any experience in using these kind of motors, I'd appreciate any advice.