New Machine Build- moving the encoder from the motor to the table

[johngalt47]

I am working on my first machine design. I have been reading everything I can get my hands on about CNC router and designs. For the last three months I have been changing my design and it is getting closer to starting the fabrication. The question I have is about using encoders mounted on the table movement instead of motor position. By measuring the table movement then all the problems with mechanics backlash wear etc. will be automatically compensated for. Has anyone seen anything on this? You could use a less expensive method of axis movement say chain instead of machined methods i.e. r/p or lead screw.

[Al_The_Man]

Systems that use this method generally have dual feedback, encoder on the motor and linear scale on the table.
If significant backlash is present, and this method is not used together with correct PID tuning, then hunting of the motor is usually a result.
Al.