Go to Post Time flies when you're freaking out. - Koko Ed [more]
Home
Go Back   Chief Delphi > FIRST > Robot Showcase
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 18-02-2011, 23:21
pfreivald's Avatar
pfreivald pfreivald is offline
Registered User
AKA: Patrick Freivald
FRC #1551 (The Grapes of Wrath)
Team Role: Mentor
 
Join Date: Jan 2007
Rookie Year: 2001
Location: Naples, NY
Posts: 2,304
pfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond repute
1551's encoder-controlled arm

This is the most complex thing we've ever coded... But thus far it appears to be easy to use and very precise!

http://www.youtube.com/watch?v=gTLMkUmhU2Y
__________________
Patrick Freivald -- Mentor
Team 1551
"The Grapes of Wrath"
Bausch & Lomb, PTC Corporation, and Naples High School

I write books, too!
  #2   Spotlight this post!  
Unread 19-02-2011, 00:16
RyanCahoon's Avatar
RyanCahoon RyanCahoon is offline
Disassembling my prior presumptions
FRC #0766 (M-A Bears)
Team Role: Engineer
 
Join Date: Dec 2007
Rookie Year: 2007
Location: Mountain View
Posts: 689
RyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond reputeRyanCahoon has a reputation beyond repute
Re: 1551's encoder-controlled arm

Looks very nicely controlled. That end screw "skewer" sticking out the front makes me a little nervous, though...

--Ryan
__________________
FRC 2046, 2007-2008, Student member
FRC 1708, 2009-2012, College mentor; 2013-2014, Mentor
FRC 766, 2015-, Mentor
  #3   Spotlight this post!  
Unread 19-02-2011, 01:09
coldfusion1279 coldfusion1279 is offline
Registered User
AKA: Mike
FRC #1279 (Cold Fusion)
Team Role: Coach
 
Join Date: Feb 2005
Rookie Year: 2004
Location: Somerville, NJ
Posts: 252
coldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud ofcoldfusion1279 has much to be proud of
Re: 1551's encoder-controlled arm

That's a great color. Good work.
__________________
Cold Fusion's 10th Season
  #4   Spotlight this post!  
Unread 19-02-2011, 03:33
Leav's Avatar
Leav Leav is offline
Spud Gun Division
AKA: Leav Oz-Ari
FRC #3316 (D-Bug)
Team Role: Mentor
 
Join Date: Dec 2004
Rookie Year: 2005
Location: Technion, Haifa, Israel
Posts: 774
Leav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond repute
Send a message via ICQ to Leav Send a message via AIM to Leav Send a message via MSN to Leav
Re: 1551's encoder-controlled arm

Quote:
Originally Posted by RyanCahoon View Post
Looks very nicely controlled. That end screw "skewer" sticking out the front makes me a little nervous, though...

--Ryan
I agree. if you have time, I would work on training your driver to protect that "skewer" from impact. This will both save you from potential penalties, and potential damage to your robot.

I would also be preparing spares for this, and figuring out what the easiest way to replace one of these was, in case it got bent beyond the ability to be screwed out.

on an unrelated note: nice programming! what are you using for feedback?

good luck!
-Leav
__________________
"We choose to build robots this season and do the other things; Not because they are easy, but because they are hard."
-Paraphrasing JFK

Participated in FIRST as a student: 2005-2006 (But still learning every season!)
Mentor: 2008 - ? (Team 2630 2008-2011, and Team 3316 since 2013)
Engineer: 2011 - ? (B.Sc. and M.Sc. in Mech. Eng. from the Technion IIT)
FIRST Volunteer - 2007 - ? (MC, FTA, FIRST Aid etc.)
  #5   Spotlight this post!  
Unread 19-02-2011, 04:48
WizenedEE's Avatar
WizenedEE WizenedEE is offline
Registered User
AKA: Adam
FRC #3238 (Cyborg Ferrets)
Team Role: Leadership
 
Join Date: Jan 2011
Rookie Year: 2010
Location: Anacortes, WA
Posts: 395
WizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to all
Re: 1551's encoder-controlled arm

[quote=Leav;1026498on an unrelated note: nice programming! what are you using for feedback?
[/QUOTE]

The title says encoders.

We're using three accelerometers (one on each part of the arm and one on the chassis) to control ours. I'm still planning for the last minute switch to potentiometers though

Did you use the jaguars' built in PID with the encoders? I'm going to try doing that for our wrist action, and I'm looking for some tips.
  #6   Spotlight this post!  
Unread 19-02-2011, 08:46
pfreivald's Avatar
pfreivald pfreivald is offline
Registered User
AKA: Patrick Freivald
FRC #1551 (The Grapes of Wrath)
Team Role: Mentor
 
Join Date: Jan 2007
Rookie Year: 2001
Location: Naples, NY
Posts: 2,304
pfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond repute
Re: 1551's encoder-controlled arm

A. Encoders with victors. No PID -- it's just not needed on these.

B. We have spares. Several of them. The entire robot is highly modular and easy to replace.

C. The screw should only ever extend out in skewer-like position when we are in scoring position for the middle row -- and thus with nothing in front of us. If the inspectors disagree, we have a plan in place (and a part half-made) to deal with it.
__________________
Patrick Freivald -- Mentor
Team 1551
"The Grapes of Wrath"
Bausch & Lomb, PTC Corporation, and Naples High School

I write books, too!
  #7   Spotlight this post!  
Unread 19-02-2011, 09:14
Nadav Zingerman Nadav Zingerman is offline
Registered User
FRC #2230
Team Role: Programmer
 
Join Date: Jul 2009
Rookie Year: 2009
Location: Israel
Posts: 90
Nadav Zingerman is a splendid one to beholdNadav Zingerman is a splendid one to beholdNadav Zingerman is a splendid one to beholdNadav Zingerman is a splendid one to beholdNadav Zingerman is a splendid one to beholdNadav Zingerman is a splendid one to beholdNadav Zingerman is a splendid one to behold
Re: 1551's encoder-controlled arm

Quote:
Originally Posted by WizenedEE View Post
The title says encoders.

We're using three accelerometers (one on each part of the arm and one on the chassis) to control ours. I'm still planning for the last minute switch to potentiometers though

Did you use the jaguars' built in PID with the encoders? I'm going to try doing that for our wrist action, and I'm looking for some tips.
You should do that right now. Accelerometers are terrible for this. You would have to integrate them twice, increasing the noise by more than a factor of two. The noise is quite bad already, and you will probably have a long cable run from the wrist to the controller, probably running next to some electrically noisy motors. If your accelerometer is analog (it probably is), this would make it impossible to use for this task. Even if it's digital, I doubt it can work at all.

Switch to encoders or potentiometers as soon as possible.
  #8   Spotlight this post!  
Unread 20-02-2011, 01:14
WizenedEE's Avatar
WizenedEE WizenedEE is offline
Registered User
AKA: Adam
FRC #3238 (Cyborg Ferrets)
Team Role: Leadership
 
Join Date: Jan 2011
Rookie Year: 2010
Location: Anacortes, WA
Posts: 395
WizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to allWizenedEE is a name known to all
Re: 1551's encoder-controlled arm

Quote:
Originally Posted by Nadav Zingerman View Post
You should do that right now. Accelerometers are terrible for this. You would have to integrate them twice, increasing the noise by more than a factor of two. The noise is quite bad already, and you will probably have a long cable run from the wrist to the controller, probably running next to some electrically noisy motors. If your accelerometer is analog (it probably is), this would make it impossible to use for this task. Even if it's digital, I doubt it can work at all.

Switch to encoders or potentiometers as soon as possible.
We're getting around 5 degrees of accuracy. We're not actually measuring the acceleration of the arm (that's one of the problems) we're measuring the acceleration of something much bigger... gravity.
Closed Thread


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 00:28.

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