For the last 6 months or so, I've been working on this project as my Senior Project for my BS in Mechanical Engineering at Cal Poly Pomona. I've created a working prototype that is constrained to 1 axis. It has 608 bearings at the base that run very smoothly to simulate a pin joint. Only having 1 axis made it much easier for me to tune the controller, and it made it cheaper while I experimented with different motor and controller options. I've finally found a setup that works, so I will be creating the full 2-axis system in the next few weeks. I anticipate that it will work similarly to my 1-axis system, but of course only time will tell if that is the case.

In the mean time, check out these videos of my working prototype!

This is a ~17" tall version that I started with:

And here is a taller version that works just about as well. It is 34" tall:

The 34" tall version is approaching the height needed for a useful monopod. My goal is 4 feet tall, but I will probably start with 3 feet for the next prototype, because I am currently maxing out the motor controllers I'm using. It would be pretty easy to increase their peak power by about 50%, which would probably make a 4 foot tall version possible, so I will probably do that right afterwards.