Non Linear Axis

I have not posted anything in a while but I have something new that I am working on that I could use some help on. We have a cylinder with internal feedback that is working a toggle. Because of the toggle the output movement is not linear to the cylinder movement and i would like to make my moves relative to the output and not the cylinder. So my plan is to use a curve for the non linear output to make everything linear. We did something similar in the advanced training a few years ago. It was the veneer lathe backup roll exercise. I think by using it as an example I can make this work.

The second part of the problem is tonnage. This is a pressing application and i will need to have a pressure limit on this axis. This axis should move to a position and another axis will be pushing against it. It will hold position till it gets to the pressure limit then maintain the force set point. This would be easy with a linear axis but I am a little unsure what to expect with the force control. As the axis is pushed back the force on the cylinder will change at a non linear rate. I think this will change the force depending on position and will also change the pressure tuning.

Any comments, questions or examples would be helpful.

Charles, nice to hear from you! Attached are the backup roll exercise and a curve file that can be imported. Change the .txt file to .rmccrvs and import it to the Curves in RMCTools. It appears that we don’t have a completed example user program.

As for the toggle motion, you may possibly need to use gain scheduling, which is explained in the RMCTools help, but there is a good chance you can tune it so it works well over the entire range. You’ll just have to see how it works out.
BackupRollCurve.txt (1.49 KB)
BackupRoll.pdf (197 KB)