motion control dual loop encoder following error

[Guzz]

i've got a complex motion control system with dual loop control (labview rt 8.01)

for some reason i'm now getting an issue with following error when i reset position on the 2 encoders (it adds the following error to the value)

if i read the following error and allow for this in the reset it does appear to zero the encoders thou when commanded to drive to position 0 is goes to the previous following error value instead

is this something to do with motor tuning?

[Robert_Lee_NIUK]

Hi Guzz,

I'm not totally sure from reading your post exactly what the problem might be, but it sounds like you may need to increase the integral term in your control application. This should improve the accuracy of your control by driving the controller towards setpoint and reducing your steady state error. I can't really tell you exactly what values you will need to adjust with, but i would reccomend slowly ramping the term up and see if there is any improvement.

Best wishes