Being new to all this, I've had a great time learning about, and then writing my own PID controller. In speaking with a mechanical engineering friend he mentioned that in his graduate level robotics class they used both PID controllers and "linear quadratic" controllers, depending on the task at hand. He specifically mentioned that for controlling a "Segway" type robot the linear-quadratic controller was better.

Anyone have experience with this? Can you point me to an easy-to-read primer on it? My first pass Googling it found a number of references, but they jumped right into the math without really describing it in english.

Thanks,
Gary

I'm bumping this because I'd also like to see an implementation of an LQR on a simple(relatively) robot.