Go to Post If the refs are not calling something that you think should be called, you have to adjust your play style to deal with it. - Rob [more]
Home
Go Back   Chief Delphi > Technical > Programming > Java
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 18-02-2012, 12:46
joelg236 joelg236 is offline
4334 Retired Mentor & Alumni
AKA: Joel Gallant
no team
Team Role: Mentor
 
Join Date: Dec 2011
Rookie Year: 2012
Location: Calgary
Posts: 733
joelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond repute
Braking with victors

2 pretty basic questions for you guys:
1.How have you managed braking so far with victors? We only have 4 jags (set up with driving) and using victors for an arm-type apparatus. We'd like to set it up so that we can stop the arm in different positions (using encoders to measure the distance) but braking with victors seems to be ineffective. Nothing happens in term of stopping the motors. The just stop outputting, and our arm falls down. Id really like some way to hold it still in one position like brakes in the jags. Is there a known way to do this>

2.For some reason initializing a victor and running victor.set(speed) does nothing for us, but initializing them as a RobotDrive works. This seems like there is something different about RobotDrive, because we use the same inputs on both. Whats the best way to use victors in the wpilibj libraries? Or do you make a class for it?
Reply With Quote
  #2   Spotlight this post!  
Unread 18-02-2012, 12:52
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,102
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: Braking with victors

Quote:
Originally Posted by joelg236 View Post
Id really like some way to hold it still in one position like brakes in the jags.
The brakes in the Jags provide dynamic braking only, not static braking. Unless you have a high gear ratio gearbox that doesn't backdrive easily, the Jags won't hold it either.

What motor are you using, and what total gear ratio (gearbox plus any sprocket ratios), and what is the magnitude of the torque required to hold the arm?


Reply With Quote
  #3   Spotlight this post!  
Unread 18-02-2012, 15:53
joelg236 joelg236 is offline
4334 Retired Mentor & Alumni
AKA: Joel Gallant
no team
Team Role: Mentor
 
Join Date: Dec 2011
Rookie Year: 2012
Location: Calgary
Posts: 733
joelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond repute
Re: Braking with victors

Gearbox ration is 256 - 1
I don't really know what the motors are, but they are really powerful.
Dont know the torque either.
Reply With Quote
  #4   Spotlight this post!  
Unread 18-02-2012, 17:08
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
 
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,102
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: Braking with victors

Quote:
Originally Posted by joelg236 View Post
Gearbox ration is 256 - 1
I don't really know what the motors are, but they are really powerful.
Dont know the torque either.
If you are using really powerful motors with a 256:1 gearbox to lift an arm, you better know the torque. There's a torque limit on those 256:1 gearboxes, and it's a lot lower than you might think.

Reply With Quote
  #5   Spotlight this post!  
Unread 18-02-2012, 18:08
jesusrambo jesusrambo is offline
Self-Proclaimed Programmer Messiah
AKA: JD Russo
FRC #2035 (Robo Rockin' Bots)
Team Role: Programmer
 
Join Date: Feb 2012
Rookie Year: 2010
Location: Carmel, CA
Posts: 114
jesusrambo is an unknown quantity at this point
Re: Braking with victors

If you have an encoder on your motors you can use a PID controller to hold them in place.
Reply With Quote
  #6   Spotlight this post!  
Unread 19-02-2012, 00:58
joelg236 joelg236 is offline
4334 Retired Mentor & Alumni
AKA: Joel Gallant
no team
Team Role: Mentor
 
Join Date: Dec 2011
Rookie Year: 2012
Location: Calgary
Posts: 733
joelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond reputejoelg236 has a reputation beyond repute
Re: Braking with victors

Yep. Our team learnt that today. Broke a gearbox. I know, derp-di-derp. Were a rookie team.
Reply With Quote
Reply


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 13:23.

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