Go to Post FIRST is the best thing I could have ever done. It shows me where I think my limits are, and it destroys them right in front of my eyes. My experiences with FIRST have defined who I am, and I am beyond blessed to have had them. - Audrey Chu [more]
Home
Go Back   Chief Delphi > Technical > Programming
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
 
 
Thread Tools Rate Thread Display Modes
Prev Previous Post   Next Post Next
  #7   Spotlight this post!  
Unread 12-05-2016, 01:43 AM
Oblarg Oblarg is offline
Registered User
AKA: Eli Barnett
FRC #0449 (The Blair Robot Project)
Team Role: Mentor
 
Join Date: Mar 2009
Rookie Year: 2008
Location: Philadelphia, PA
Posts: 1,047
Oblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond reputeOblarg has a reputation beyond repute
Re: Velocity PID(F) Best Practices - To Integrate, or Not To Integrate?

Just thought I'd report back - we just got a flywheel working with a PF loop, basically exactly as described above. Indeed, there is plenty of headroom to make the P term big enough that the steady-state error is negligible (plus or minus ~.2 RPS) without the system becoming unstable. We'll see about tuning our drive this way next, though we need a few more talons to do that.

Just a note about PID control on the talons: god, the handling of the units in the java WPILib code is terrible. "Native units" (which are noted to be either per 10ms or per 100ms depending on which source you check; they are actually the latter) are used everywhere *except* for the set and getsetpoint functions, which use RPM. The comments helpfully mention that the latter function returns a value in "appropriate units." Also, the output scaling for F gain is -1023 to 1023, which is a sort of odd choice.

On the plus side, the loop works great.

I hope, before too long, to try tuning a variety of systems using both strategies and actually compare the performance.
__________________
"Mmmmm, chain grease and aluminum shavings..."
"The breakfast of champions!"

Member, FRC Team 449: 2007-2010
Drive Mechanics Lead, FRC Team 449: 2009-2010
Alumnus/Technical Mentor, FRC Team 449: 2010-Present
Lead Technical Mentor, FRC Team 4464: 2012-2015
Technical Mentor, FRC Team 5830: 2015-2016
Reply With Quote
 


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 04:48 AM.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi