Go to Post Please forgive any possible profound language. - PortugazD.Ace [more]
Home
Go Back   Chief Delphi > Technical > Motors
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 21-02-2011, 09:26
explodingcan's Avatar
explodingcan explodingcan is offline
Hilo Viking Robotics Webmaster
AKA: Luke
FRC #1378 (Green Label Zealots)
Team Role: Webmaster
 
Join Date: Feb 2008
Rookie Year: 2008
Location: Hilo Hawaii
Posts: 23
explodingcan is an unknown quantity at this point
Exclamation Swerve Drive complications

Our robot is rectangular shaped and using a swerve drive. As we ran a few tests, we realized that the robot wasn't able to turn.

We did not know that the robot needed to be a perfect square in order for the robot to turn.

We need ideas as to how to fix this problem ASAP.

Anything is appreciated. Thank you
__________________


  #2   Spotlight this post!  
Unread 21-02-2011, 09:29
Bjenks548's Avatar
Bjenks548 Bjenks548 is offline
Registered User
AKA: Brendan
FRC #0548 (Robostangs)
Team Role: Alumni
 
Join Date: Mar 2010
Rookie Year: 2009
Location: Northville
Posts: 354
Bjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond reputeBjenks548 has a reputation beyond repute
Re: Swerve Drive complications

What pods are slaved together for driving the wheels?
__________________
Toronto Regional quarter finalists. Northville Winners/ Chairman's Winners. Troy Finalist/ GM Industrial Design Award. Michigan State Championship Finalists. CMP Newton Division winners! Triple Balance count 13. Thanks to 1075, 4307, 67, 3656, 217, 2604, 2054, 245, 118, and 2194! Photo credit for my avatar Dan Ernst


  #3   Spotlight this post!  
Unread 21-02-2011, 09:32
explodingcan's Avatar
explodingcan explodingcan is offline
Hilo Viking Robotics Webmaster
AKA: Luke
FRC #1378 (Green Label Zealots)
Team Role: Webmaster
 
Join Date: Feb 2008
Rookie Year: 2008
Location: Hilo Hawaii
Posts: 23
explodingcan is an unknown quantity at this point
Re: Swerve Drive complications

Quote:
Originally Posted by Bjenks548 View Post
What pods are slaved together for driving the wheels?
all four are on the same steering motor
__________________


  #4   Spotlight this post!  
Unread 21-02-2011, 09:34
MrForbes's Avatar
MrForbes MrForbes is online now
Registered User
AKA: Jim
FRC #1726 (N.E.R.D.S.)
Team Role: Mentor
 
Join Date: Feb 2006
Rookie Year: 2006
Location: Sierra Vista AZ
Posts: 6,033
MrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond reputeMrForbes has a reputation beyond repute
Re: Swerve Drive complications

If you provide several pictures of the robot, including some with just the chassis, we might be able to see what you're up against, and offer helpful suggestions.
  #5   Spotlight this post!  
Unread 21-02-2011, 09:34
WileyB-J's Avatar
WileyB-J WileyB-J is offline
4976 Georgetown Rebels
FRC #4976 (Rebels)
Team Role: Mentor
 
Join Date: Feb 2011
Rookie Year: 2008
Location: Burlington, ON
Posts: 97
WileyB-J will become famous soon enoughWileyB-J will become famous soon enough
Re: Swerve Drive complications

Quote:
Originally Posted by explodingcan View Post
all four are on the same steering motor
wouldn't you need two separate steering motors to be able to pivot?
  #6   Spotlight this post!  
Unread 21-02-2011, 09:38
Vikesrock's Avatar
Vikesrock Vikesrock is online now
Team 2175 Founder
AKA: Kevin O'Connor
no team
Team Role: Engineer
 
Join Date: Mar 2006
Rookie Year: 2007
Location: Manchester, NH
Posts: 3,305
Vikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond repute
Send a message via AIM to Vikesrock Send a message via MSN to Vikesrock Send a message via Yahoo to Vikesrock
Re: Swerve Drive complications

Quote:
Originally Posted by WileyB-J View Post
wouldn't you need two separate steering motors to be able to pivot?
You can pivot if the pods are all steered together if they are not all powered together.

As Squirrel suggested a picture or two and some descriptions of the driving setup (driven in pairs or independently?) would allow us to give you some suggestions.
__________________


2007 Wisconsin Regional Highest Rookie Seed & Regional Finalists (Thanks 930 & 2039)
2008 MN Regional Semifinalists (Thanks 2472 & 1756)
2009 Northstar Regional Semifinalists (Thanks 171 & 525)
  #7   Spotlight this post!  
Unread 21-02-2011, 09:43
explodingcan's Avatar
explodingcan explodingcan is offline
Hilo Viking Robotics Webmaster
AKA: Luke
FRC #1378 (Green Label Zealots)
Team Role: Webmaster
 
Join Date: Feb 2008
Rookie Year: 2008
Location: Hilo Hawaii
Posts: 23
explodingcan is an unknown quantity at this point
Re: Swerve Drive complications

Quote:
Originally Posted by Vikesrock View Post
You can pivot if the pods are all steered together if they are not all powered together.

As Squirrel suggested a picture or two and some descriptions of the driving setup (driven in pairs or independently?) would allow us to give you some suggestions.
They are ALL powered differently. Photo coming up as soon as possible.

It is currently on Arcade drive with an open four motors jaguar
__________________


  #8   Spotlight this post!  
Unread 21-02-2011, 09:52
explodingcan's Avatar
explodingcan explodingcan is offline
Hilo Viking Robotics Webmaster
AKA: Luke
FRC #1378 (Green Label Zealots)
Team Role: Webmaster
 
Join Date: Feb 2008
Rookie Year: 2008
Location: Hilo Hawaii
Posts: 23
explodingcan is an unknown quantity at this point
Re: Swerve Drive complications

Here are photos: http://hilovikingrobotics.com/first/swerve/
__________________


  #9   Spotlight this post!  
Unread 21-02-2011, 10:04
Vikesrock's Avatar
Vikesrock Vikesrock is online now
Team 2175 Founder
AKA: Kevin O'Connor
no team
Team Role: Engineer
 
Join Date: Mar 2006
Rookie Year: 2007
Location: Manchester, NH
Posts: 3,305
Vikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond repute
Send a message via AIM to Vikesrock Send a message via MSN to Vikesrock Send a message via Yahoo to Vikesrock
Re: Swerve Drive complications

Yes, when the wheels are pointed forward that drive will act like a 4WD in the long configuration which many teams have discovered over the years has difficulty turning if all 4 wheels are high traction.

The robot likely will be able to rotate if the wheels are pointed sideways. Not exactly an ideal solution, but any solution is better than no solution.
__________________


2007 Wisconsin Regional Highest Rookie Seed & Regional Finalists (Thanks 930 & 2039)
2008 MN Regional Semifinalists (Thanks 2472 & 1756)
2009 Northstar Regional Semifinalists (Thanks 171 & 525)
  #10   Spotlight this post!  
Unread 21-02-2011, 10:06
thefro526's Avatar
thefro526 thefro526 is offline
Mentor for Hire.
AKA: Dustin Benedict
no team (EWCP, MAR, FRC 708)
Team Role: Mentor
 
Join Date: Aug 2006
Rookie Year: 2005
Location: New Jersey
Posts: 2,599
thefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond reputethefro526 has a reputation beyond repute
Send a message via AIM to thefro526 Send a message via MSN to thefro526
Re: Swerve Drive complications

Your turning issues have nothing to do with the fact that you're using a swerve drive.

Long base, four wheel drive robots will have issues turning with 4 high traction wheels even if they aren't a swerve drive. A quick fix to this problem would be to swap the front or rear wheels out to omni-directional wheels so you have less lateral resistance to turning.

Another solution would be to add a second steering motor and steer the front and rear wheels independently in turning.

You could also reposition your swerve modules so that the contact points of the wheels create a perfect square, or close to it...
__________________
-Dustin Benedict
2005-2012 - Student & Mentor FRC 816
2012-2014 - Technical Mentor, 2014 Drive Coach FRC 341
Current - Mentor FRC 2729, FRC 708
  #11   Spotlight this post!  
Unread 21-02-2011, 10:10
big1boom big1boom is offline
Chains=Fun
FRC #2022 (Titan Robotics)
Team Role: Alumni
 
Join Date: Jan 2009
Rookie Year: 2007
Location: Aurora
Posts: 267
big1boom is a glorious beacon of lightbig1boom is a glorious beacon of lightbig1boom is a glorious beacon of lightbig1boom is a glorious beacon of lightbig1boom is a glorious beacon of lightbig1boom is a glorious beacon of light
Re: Swerve Drive complications

Assuming that your wheel pods are able to rotate while on the ground...
Looks like you have discovered why it is recommended to use a 6WD instead of a 4WD long tank.

At max weight, your motors will not have enough force to overcome the scrub caused by driving the wheels in opposite directions.

3 Possible solutions exist.
1) Turn in the wide configuration, rather than long.
2) Add another turning motor so that the front/back are separate.
3) Swap in omni wheels for one of your sets. However this kinda defeats the purpose of swerve.
__________________
  #12   Spotlight this post!  
Unread 21-02-2011, 10:29
Hawiian Cadder's Avatar
Hawiian Cadder Hawiian Cadder is offline
Registered User
AKA: Isaak
FRC #0159 (Alpine Robotics)
Team Role: CAD
 
Join Date: Feb 2010
Rookie Year: 2003
Location: Fort Colins Colorado
Posts: 573
Hawiian Cadder is a name known to allHawiian Cadder is a name known to allHawiian Cadder is a name known to allHawiian Cadder is a name known to allHawiian Cadder is a name known to allHawiian Cadder is a name known to all
Re: Swerve Drive complications

if you redo the chains that are turning to form an X rather than II configuration, then you will be able to turn, the disadvantage is it requires some recoding. the x means that two wheels on either corner are always parallel, which makes the robot turn around the point where the chains cross.
  #13   Spotlight this post!  
Unread 21-02-2011, 10:35
KrazyCarl92's Avatar
KrazyCarl92 KrazyCarl92 is offline
Registered User
AKA: Carl Springli
FRC #0020 (The Rocketeers)(EWCP)
Team Role: Mentor
 
Join Date: Jan 2010
Rookie Year: 2010
Location: Clifton Park, NY
Posts: 523
KrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond reputeKrazyCarl92 has a reputation beyond repute
Re: Swerve Drive complications

Solution: whenever you usethe turn command on the controller, first turn the wheels so that they are in a wide wheel base configuration rather than narrow. Then power the proper wheels in the proper direction and watch the robot turn very easily. There is almost no four wheel crab drive configuration allowed by the dimensions in the rules that would not allow a robot to turn unless your wheels just have a ridiculous amount of traction that causes ridiculous amounts of scrubbing.
__________________
[2017-present] FRC 0020 - The Rocketeers
[2016] FRC 5811 - BONDS Robotics
[2010-2015] FRC 0020 - The Rocketeers
  #14   Spotlight this post!  
Unread 21-02-2011, 10:40
explodingcan's Avatar
explodingcan explodingcan is offline
Hilo Viking Robotics Webmaster
AKA: Luke
FRC #1378 (Green Label Zealots)
Team Role: Webmaster
 
Join Date: Feb 2008
Rookie Year: 2008
Location: Hilo Hawaii
Posts: 23
explodingcan is an unknown quantity at this point
Re: Swerve Drive complications

THANK YOU FOR ALL YOUR SUGGESTIONS! WE HAVE SOLVES OUR PROBLEM BY ROTATING OUR WHEELS HORIZONTALLY!!!

this was certainly a perfect display of gracious professionalism
__________________


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 15:10.

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