On Sat, 22 Dec 2012, Stephen Dubovsky wrote:
> Date: Sat, 22 Dec 2012 16:29:39 -0500
> From: Stephen Dubovsky <[email protected]>
> Reply-To: "Enhanced Machine Controller (EMC)"
> <[email protected]>
> To: "Enhanced Machine Controller (EMC)" <[email protected]>
> Subject: Re: [Emc-users] Pid saturated, was: Servo error
>
> Peter,
> I *FULLY* understand. My 8th paragraph states if the drive is poorly tuned
> (voltage mode = no tuning) and the poles are low in freq (bingo) the D is a
> bandaid. Voltage mode control doesn't hide/move the plant poles to a
> higher freq like current mode can. Its simpler but lower performance.
> Only so much bandwidth a single loop can get if it gets handed all the
> multi-order system resonances in one black box. Much better to handle each
> system order at a time (torque,speed,position). The D adds zero which if
> you put ontop of the next systems pole you can help things out. There are
> systems that it works in. Buts its a bandaid.
Um no, you dont. I was giving advice on how to tune a voltage mode loop, Your
advice does not apply in this context. Its very clear that you have not
actually tuned a voltage mode loop. D is absolutely needed for stability, A
voltage mode drive with velocity feed forward approximates a torque mode loop
(a second order system). Without a D term the solution to this system
function is a sine wave.
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
------------------------------------------------------------------------------
LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial
Remotely access PCs and mobile devices and provide instant support
Improve your efficiency, and focus on delivering more value-add services
Discover what IT Professionals Know. Rescue delivers
http://p.sf.net/sfu/logmein_12329d2d
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users
