Can a PID motor control be implemented in CREO mechanism?

[Sweetpeahub-old]

Is it possible to implement a PID (Proportional - Integral - Derivative) speed or position control on a motor in CREO mechanism?  Here is an example of a basic (non PID) speed control I have used with a torque motor.  What if there is a specific algorithm used by the control circuit such as PID?  Are there some example of how this might be implemented?  Is Custom Loads a possible or preferred way to do this?

Torque Motor Speed Control Method

[SweetPeasHub]

Sorry, this is me. I used the wrong login.

[ChrisKaswer · Accepted solution]

Yes, you can! There was an old example model that PTC posted many years ago when the tool was "Mechanica Applied Motion". I have used this same model to have it run properly in Creo 5...at least it appears to run properly, as I haven't checked the details of all results to know it's accurate. I have attached a PDF of the original paper posted many years ago and my comments on how this should be modified to get the desired result in Creo (even those are old now!). The model is also attached (Creo 2 version).

Enjoy,

Chris

[gfraulini]

Hi,
I wonder how one can limit the torque of the motor (in plus and minus).
I worked on your model and I saw that If I add only 1 torque motor, instead of 3, who is commanded by a user defined measure (that is the sum of the measur of the 3 troque motors) I have the same behavior as before.

But if I try to limit this new motor (-600<=total torque<=+600) the system doesn't respond well.

What am I doing wrong?

[Sweetpeahub-old]

Did you try adjusting the gains?  Particularly the integral gain should be reduced for a saturated system.

[gfraulini]

You suggest to decrease Ki, right?
What do you mean for "saturated system"? Sorry but I don't understand well motion control...

[gfraulini]

I would like to be capable to limit the total torque of the motor up to 600 Nmm like a brushless motor that has 600 as max torque value.

[gfraulini]

In the attached file, at page 5 point 7 of the list, one says to edit the C parameter of the polynomial formula, that is the quadratic coefficient. But in your Creo file you have edited the B coefficient, that's the linear one. I also think that it is correct what you've done, but I wonder if it would have sense to change C coefficient.

[SweetPeasHub]

Just my $0.02 I seem to remember there was a procedure to tune all 3 of the gains in my Controls Systems lab classes... 26 years ago.

[gfraulini]

It was written at the top of the doc...