Has anyone tried to used Pololu Wheel Encoders on this platform? I think they can be secured in place with one scew and a bit of glue. One could argue they might not work well with The Trax wheels but I would bet it would be better control with no encoders at all. You could always go with 2 wheel drive and put wheels on instead of the Trax.
In our tests, the wheel encoders didn’t work well with our tracks since the tracks don’t block as much ambient light as tires, so the reflectance sensors don’t get as much contrast. You might be able to get better results from the sensors by attaching something to the chassis to shield them from light.
I tried replacing the tracks on a Zumo with tires, but that didn’t work well either since the weight of the batteries is mostly on the idler wheels, so the drive wheels couldn’t get enough traction spinning by themselves.
If you do try to make the encoders work, we would be interested to hear what kind of results you get.