TOS-KURIM CNC Upgrade

[Muzzer]

Yes, there's no magic solution to backlash and accuracy. The idea of closing the loop with external DRO scales sounds pretty neat but as Boyan says, it's only very expensive controllers that support that concept. And an expensive system using such a controller probably has very little mechanical nonlinearity and/or backlash to start with.

If you have a basic system with loads of backlash, no controller in the world will be able to able to make sense of the nonlinear behaviour in a sensible way. Imagine trying to drive a car down a windy road with half a turn of lost movement on the steering wheel, then trying to fix that by adding some form of simple closed loop.

Your system is either going to be worn out in which case you need to either live with it or fix it - or it's in good shape in which case you should just fit a modern controller and get on with life. Sounds as if it's quite a decent machine to start with. Apart from bragging rights, what accuracy do you think you actually need? 10-20um? That's still 50th - 100th of a mm. I would start by measuring what I have and take it from there.

[Voicecoil]

. Imagine trying to drive a car down a windy road with half a turn of lost movement on the steering wheel, then trying to fix that by adding some form of simple closed loop.

I can identify with that having once borrowed a friends Series 1 LandRover that had 30...40 degrees play in the steering wheel before anything happened