This happens when:
– The Theta and Psi wheels are not printed completely round
– The Theta and Psi wheels are not the same size
– The arm segments are not exactly 150mm (or whatever you set in the firmware setup)
In selfbuilt systems you can get combinations of the above…
There is a calibration procedure with a special model that you print, and a spreadsheet can assist with the settings. I will update it this week and add it to the Morgan site probably this weekend.
Will let you know when it is up.