I have a rotary table (4th axis) that has considerable friction. I know this because the DC servo motor requires at least about 4 amps, to turn the table.
The rotary table has a tight worm drive, not some sort of a ballscrew, and the drive is hard to turn. I did try that without the motor, by hand, and it was clearly a bit hard to move. I finally got the table work with EMC2 (thanks to Jon), and have a problem with is a high following error. The error is 0.04 degrees. Since there is a considerable reduction ratio in the work drive, the following error amounts to something like 5 degrees of a turn of the motor (I may be off with my math VERY easily, but clearly it is huge with that much reduction). Right or wrong, I attribute this to the friction in the worm drive system -- the servo motor develops following error when working against friction. I have AMC DC drives working in torque mode. My question is what servo tuning parameters could I use to compensate for high friction. It seems that I almost need FF(-1) or something like that? Thanks i ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
