Did anyone used linear hall sensors on BLDCs for position sensing? (12 replies)

I am searching for a suitable solution for using DC motors (actually BLDC) to create closed-loop position controls that could replace/improve over the steppers we use in most of our 3D printers.

While I do have several motors running successfully with my code: [www.youmagine.com] one key part of this quest is to get the price right. Not many are going to buy a $100 motor just to keep their printers from skipping a step occasionally.

So I am working to get the cost down to a similar level than a stepper plus its drive electronics (at around $15 each).

All my tests so far have use incremental encoders for providing position feedback.

But recently the use of linear hall sensors to both help with BLDC conmutation and figure out the shaft position without the need of an encoder have been brought up to my attention.

So here is my question to you guys: have you used linear hall sensors to replace an incremental encoder with success?

I have found a paper that suggests it can be done easily: [homes.cs.washington.edu] but I will be more confident if a fellow reprapper already tested that solution space.

Suffice is to say that dropping the encoder will further decrese the cost of such a closed-loop BLDC contraption.

Thanks a lot,

misan