Any discussion around steppers and encoders should now include smarter drivers like the LAM DS series that have a boost function that allows the current to be increased to the driver as required. Tommy has experimented with enabling this boost feature based on following errors measured via an encoder. However, a more normal use would be to reduce the current when the axis is coasting at speed and not accelerating (which is where the greatest torque requirement occurs). From the modelling we've done, a well matched stepper motor may require a lot lower current than its maximum rating to do a particular job so it all starts to make sense.... So if additional current was boosted when the following error got close to loosing steps, the drive might be able to catch up.
I will be experimenting with this when I get to it. I was thinking of building a component that reduced the current if the velocity was not changing between servo periods. If you have a system designed to work at up to 10 m/min and its only moving at 2m/min, it stands to reason the torque requirements are much reduced so there is a lot of scope to be gentler on the drives.
