Well, start researching various microcontrollers. I would suggest you try some small projects first. While far from an "industrial strength" microcontroller, you can purchase a Parallax Basic Stamp for a reasonable price. It makes digital I/O simple, and you can make some neat things with it.
www.parallax.com
Part of my graduate research work was in autonomous mobile robot control architectures. I can tell you, it is far from a simple task -- if not insurmountable for someone with little low level programming experience. Besides that, designing control systems is highly mathematical. I'm not trying to rain on your parade, I just want you to understand that what you're asking for is probably more involved than you think it is.
Like anything else, start small, learn the basics, and move on to bigger & better things.