Dynomotion

Group: DynoMotion Message: 12086 From: alexera753 Date: 8/8/2015
Subject: noise in output
Hi Tom
i attached two image about Step Response, i can see that have noise in output.
how i can correct it ? with which parameter ?


Alex

   @@attachment@@
Group: DynoMotion Message: 12087 From: Tom Kerekes Date: 8/9/2015
Subject: Re: noise in output [2 Attachments]
Hi Alex,

That doesn't look too bad.  You didn't zoom in enough or plot Position Error so we could see clearly (or post the raw data so we could).

I assume that is a DAC Servo?  What is your resolution?  What is your lead screw pitch?

That may be just vibration or lead screw wobble that the servo is correcting.

More D Gain (combined with a 2nd order 1KHz Q1.4 Low Pass filter) may help and also allow higher P and I gains.

HTH
Regards
TK 

Group: DynoMotion Message: 12089 From: Alex Era Date: 8/9/2015
Subject: Re: noise in output
Hi Tom
Yes , is DAC servo, my servo system need 4000 pulse for a turn. i have a 2:1 gearbox with belt and ballscrew is 5mm pitch.

"More D Gain (combined with a 2nd order 1KHz Q1.4 Low Pass filter) may help and also allow higher P and I gains."
about this issue , i think you insert good information about filter in site , but not enough . do you can record a video about filter effect?
in addition, about Bode Plote , your dscribe isnt enough.
sorry but this is my opinion .
thx for all support

another issue , about Feedrate . when we change feedrate we see effect after long time . i think cause is "look ahead" .
i need Immediate effect , there is any ways ?

Regard
Alex



On Sunday, August 9, 2015 9:50 PM, "Tom Kerekes tk@... [DynoMotion]" <DynoMotion@yahoogroups.com> wrote:


 
Hi Alex,

That doesn't look too bad.  You didn't zoom in enough or plot Position Error so we could see clearly (or post the raw data so we could).

I assume that is a DAC Servo?  What is your resolution?  What is your lead screw pitch?

That may be just vibration or lead screw wobble that the servo is correcting.

More D Gain (combined with a 2nd order 1KHz Q1.4 Low Pass filter) may help and also allow higher P and I gains.

HTH
Regards
TK 

Group: DynoMotion Message: 12090 From: Tom Kerekes Date: 8/9/2015
Subject: Re: noise in output
Hi Alex,

The main purpose for using the Low pass filter is to reduce spikes in the Output that your Amplifier may not like.  For example when using a D Gain of say 100 then each time the encoder suddenly changes by 1 count the output will spike 100 DAC counts for 1 Servo Sample.  A low pass filter will smooth this out over a few samples.  The low pass filter should use the 3rd filter so that it also applies to any Feed Forward.  See:


Unfortunately Servo Tuning is fairly complex and difficult and will vary with each system.

Ben posted a great tuning guide.  It is for a SnapAmp configuration but the basic methods are the same.  See:

Regarding FeedRate changes.  You can define what range will be performed in hardware for instant response.  See:

And a Video:

HTH
Regards
TK


Group: DynoMotion Message: 12091 From: az@aimele.com Date: 8/9/2015
Subject: Re: noise in output
Tom:
Just jumping in with a question / clarification about FRO.  Doesn't hardware FRO capability start at test version 4.33l(L)?  not at the current release 4.32?  I spent a few frustrating hours looking for it in 4.32 about two weeks ago.

AZ


------- Original Message -------
From : Tom Kerekes tk@... [DynoMotion][mailto:DynoMotion@yahoogroups.com]
Sent : 8/9/2015 2:28:19 PM
To : DynoMotion@yahoogroups.com
Cc :
Subject : RE: Re: [DynoMotion] noise in output

 

Hi Alex,

The main purpose for using the Low pass filter is to reduce spikes in the Output that your Amplifier may not like.  For example when using a D Gain of say 100 then each time the encoder suddenly changes by 1 count the output will spike 100 DAC counts for 1 Servo Sample.  A low pass filter will smooth this out over a few samples.  The low pass filter should use the 3rd filter so that it also applies to any Feed Forward.  See:


Unfortunately Servo Tuning is fairly complex and difficult and will vary with each system.

Ben posted a great tuning guide.  It is for a SnapAmp configuration but the basic methods are the same.  See:

Regarding FeedRate changes.  You can define what range will be performed in hardware for instant response.  See:

And a Video:

HTH
Regards
TK


Group: DynoMotion Message: 12092 From: Tom Kerekes Date: 8/9/2015
Subject: Re: noise in output
Hi AZ,

Hardware FRO was first added in Version 4.33a.

Regards
TK

From: "'az@...' az@... [DynoMotion]" <DynoMotion@yahoogroups.com>
To: DynoMotion@yahoogroups.com
Sent: Sunday, August 9, 2015 1:12 PM
Subject: RE: Re: [DynoMotion] noise in output

 
Tom:
Just jumping in with a question / clarification about FRO.  Doesn't hardware FRO capability start at test version 4.33l(L)?  not at the current release 4.32?  I spent a few frustrating hours looking for it in 4.32 about two weeks ago.

AZ


------- Original Message -------
From : Tom Kerekes tk@... [DynoMotion][mailto:DynoMotion@yahoogroups.com]
Sent : 8/9/2015 2:28:19 PM
To : DynoMotion@yahoogroups.com
Cc :
Subject : RE: Re: [DynoMotion] noise in output

 
Hi Alex,

The main purpose for using the Low pass filter is to reduce spikes in the Output that your Amplifier may not like.  For example when using a D Gain of say 100 then each time the encoder suddenly changes by 1 count the output will spike 100 DAC counts for 1 Servo Sample.  A low pass filter will smooth this out over a few samples.  The low pass filter should use the 3rd filter so that it also applies to any Feed Forward.  See:


Unfortunately Servo Tuning is fairly complex and difficult and will vary with each system.

Ben posted a great tuning guide.  It is for a SnapAmp configuration but the basic methods are the same.  See:

Regarding FeedRate changes.  You can define what range will be performed in hardware for instant response.  See:

And a Video:

HTH
Regards
TK