I am relatively new to 3D printing, but have some background in industrial equipment and test machines.
An important part of printer setup is getting the extruder mm/step rate configured correctly.
I was wondering if anybody has done any research into closed loop drive of the filament where the feedback to close the loop comes from a knurled idler on the filament.
This would mean factors such as drive slippage and different material stiffness could be automatically compensated for.
Going one step further the feedback wheel could be placed at the hotend of Bowden extruder systems negating the need to tune in retract settings for different materials as the closed loop system can just pull back however much material is required to get 1-2 mm as measured at the hot end.
I have seen there are readily available steppers with drive boards built in for closed loop control, I would imagine it would be a relatively simple task to remove the hall effect sensor from one of these boards and mount it remotely to read off a measuring wheel instead of the drive shaft.
I had a bit of a search but couldn't find anything on this topic online, is this something that has already been looked into and if it hasn't are there any significant reasons why this shouldn't work to improve performance and/or reduce manual tweaking and calibration required.