Self-Balancing Scooter/Unicycle - Advice Needed

Projects General Guidance
1

Hi Arduino Community,

I'm building a 2-wheel self balancing scooter, similar to a electric unicycle, but with two wheels side-by-side. I'm a mechanical engineer by schooling and now do mostly software, so I could use some input in the electrical engineering department.

I've attached my electrical diagram and a hand-sketch of the project. I'd like some advice on these areas:

  1. Should I use a 25A or 40A controller with the 48V 1000W hub motors?
  2. What size fuse should I use in this diagram?
  3. What gauge wire do I need to run between the battery and the motor controllers?
  4. Is there anything I'm noticeably missing?

If anyone has any recommendations on my approach, I would love to hear it! I've considered going with the roboteQ BLDC 2-channel controller, since it has better regenerative braking and doesn't have a "dead-zone" in between forward and reverse (I'll have to calibrate that out in the code for the kelly controller), but it is twice as expensive.

Thanks for any input!

Circuit Diagram.jpg
Circuit Diagram.jpg1399×743 155 KB

Draw1.jpg
Draw1.jpg2016×1512 747 KB

2

The missing part is the 1/20 scale self balancing robot that you need to design, build and perfect before you even think about building something that has enough power to support a person.

3

The Arduino and MPU I'm using is coming directly from the self-balancing robot that I bought. I only really had to tune the PID of the open source code, so that was trivial. I'm hoping to scale this, but it used brushed motors and didn't have many of the safety considerations I'll need for this build.

I'd definitely like to break down the balancing algorithm significantly more and implement a kalman filter for prediction, but I think I'm at an OK place right now.

Any input on my open questions would be most appreciated.