Go to Post from time to time, we all need a good smack to make us see when we screwed up and did something we shouldn't have. - Andrew Schreiber [more]
Home
Go Back   Chief Delphi > Technical > Technical Discussion
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
  #16   Spotlight this post!  
Unread 09-11-2011, 13:42
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,126
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Robot loosing communication when switching directions

Quote:
Originally Posted by kinganu123 View Post
@Ether, could you please explain to me what you mean by a 2.4X reduction? We are using 8" Mecs and I believe the ratio is 1:3 or some absurdly low number.
I said 2.4x additional reduction.

You said in an earlier post "I'm wondering if direct driving Mechanum Wheels using 4 - CIMple Boxes wasn't enough of a mechanical reduction and hence cause too much draw".

If you are direct-driving 8" wheels with nothing but a CIMPLE box for gear reduction, your motors are overloaded. CIMPLE box provides 4.67:1 reduction. You need more gear reduction. Preferably at least 2.4x more gear reduction. So, 2.4x4.67 = 11.2 total reduction from CIM shaft to wheel.





Last edited by Ether : 09-11-2011 at 13:53. Reason: added links
  #17   Spotlight this post!  
Unread 09-11-2011, 14:40
EricVanWyk EricVanWyk is offline
Registered User
no team
 
Join Date: Jan 2007
Rookie Year: 2000
Location: Boston
Posts: 1,597
EricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond reputeEricVanWyk has a reputation beyond repute
Send a message via AIM to EricVanWyk
Re: Robot loosing communication when switching directions

Quote:
Originally Posted by Ether View Post
I said 2.4x additional reduction...
I think this should be treated as a separate issue, possibly in a separate thread. Incorrect motor reductions should be unable to cause the root issue, provided the electrical system is fine. They can definitely aggravate the issue, but they won't be the root cause. Even if the problem appears to go away after changing the reduction, it will still be lingering in the background (and harder to debug when it returns).

As many other have already said, move the radio to the dedicated radio power supply. Also, add a few things to your standard pre-flight checklist - electrical connector security, chassis fault, motor chassis fault.
  #18   Spotlight this post!  
Unread 09-11-2011, 16:40
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,126
Ether has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond reputeEther has a reputation beyond repute
Re: Robot loosing communication when switching directions

Quote:
Originally Posted by EricVanWyk View Post
Incorrect motor reductions should be unable to cause the root issue, provided the electrical system is fine. They can definitely aggravate the issue, but they won't be the root cause.
I agree the motor reduction is not the root cause, I should have been clearer.

You still should consider changing that gear ratio though, kinganu123. PM me if you'd like some additional useful links.


  #19   Spotlight this post!  
Unread 09-11-2011, 17:34
kinganu123 kinganu123 is offline
Registered User
FRC #1747
Team Role: Mentor
 
Join Date: Jan 2010
Rookie Year: 2008
Location: Piscataway, NJ
Posts: 243
kinganu123 is on a distinguished road
Re: Robot loosing communication when switching directions

Quote:
Originally Posted by Mark McLeod View Post
If your radio is taking 5 minutes to reconnect to the field, then it could be that the manual switch on the back of the DLink is in the Auto position rather than Bridge.
Actually, at Brunswick Eruption, we had no connection to the networks for the first 3/4 for matches. So we did a manual override by setting it to AP and connecting the netbook to the receiver.

Quote:
Originally Posted by Joe Ross View Post
Have you rewired the robot since competition, or were you able to pass inspection twice with the radio wired to a PD breaker?
We have rewired the robot because it was atrocious, but the freshmen who were assigned to the job were told to wire it the same exact way it was before they redid it. So that could be where the problem started. But I don't recall wiring the bridge to the dedicated port in the first place.
and yes, we did pass inspection the way the radio was wired
Twice at Trenton and twice at Philly
__________________
  #20   Spotlight this post!  
Unread 10-11-2011, 14:29
powellstark powellstark is offline
Junior Member
None #0003
 
Join Date: Nov 2011
Location: USA
Posts: 1
powellstark is an unknown quantity at this point
Re: Robot loosing communication when switching directions

Check the power chords and the way they are fixed. There might be a loose contact and due to the movement they might be missing contact with the power and stopping its function.
  #21   Spotlight this post!  
Unread 27-12-2011, 15:35
kinganu123 kinganu123 is offline
Registered User
FRC #1747
Team Role: Mentor
 
Join Date: Jan 2010
Rookie Year: 2008
Location: Piscataway, NJ
Posts: 243
kinganu123 is on a distinguished road
Re: Robot loosing communication when switching directions

sorry for not following up with you guys, but I went ahead and wired the router to the dedicated power source and it worked!
thanks a bunch guys!
__________________
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 14:33.

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