Oscilllating in Position mode

14 years 5 months ago #13351257 by hemantdandekar

In position mode the motor start moving for commanded position and finally continue to oscillate thereafter instead of halting at final position. What fundamental mistake we are cimmiting.

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14 years 5 months ago #13376792 by cosma
Replied by cosma on topic Re:Oscilllating in Position mode

There are two components that you can tune to achieve stability.

First, you should have a divider ratio that is not too small.

The optimal value depends mostly on the number of cpr of your encoder.<BR>If the divider is too small, the motor will be asked to stop within a very narrow range that may be mechanically too difficult or impossible for your motor to achieve.

The second element are the PID parameters. Bad tuning will lead to oscillation. Try first eliminating the D parameter (0) and have I at 0 or near 0/.

Play with the P value until you get the best response possible.

Then add a little I. I is needed to make sure that the destiation is actually reached as P become mostly ineffective when you are near the destination.,

You may then add some D to make the system respond faster, keeping in mind that this may eventually bring some instability.

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