Re: DIY AC Servo Drive - ATMega based
Originally Posted by
mcm_xyz
Quick question...
I came across a logic problem.
For eg the X axis movement in any direction requires same amount of power. However for a Z axis for eg It's harder to move it up than down. If my Z axis has 10 kilos, then we have a 20 kilos force differnce between directions.
Question is: have any of you heard about servo drives with 2 sets of parameters for PID, 1 for each direction? Or something similar...
Mihai
You shouldn't need it, because its normal to have load in one direction only (EG: when cutting hard.) Your PID should be able to be stable both directions.
But on a Z axis, you could add a "Offset" setting which makes the error zero when the load is on. ( i have that in my viper) You just make the PWM sit normally with a bit of offset.+ or -
Larry K
Manufacturer of CNC routers and Viper Servo Drives
www.LarkenCNC.com and www.Viperservo.com