Go to Post Such reasonableness will not be tolerated! This is teh interwebz! - pfreivald [more]
Home
Go Back   Chief Delphi > Technical > Electrical
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 22-07-2015, 12:37
robotsarecool robotsarecool is offline
Registered User
no team
 
Join Date: Jul 2015
Location: Washington
Posts: 7
robotsarecool is an unknown quantity at this point
Electrical Board for mecanum

How would an electrical board for a robot with a mecanum drive train be different from one with a tank drive train? Any help is appreciated, thanks!
  #2   Spotlight this post!  
Unread 22-07-2015, 12:56
Ari423's Avatar
Ari423 Ari423 is offline
LabVIEW aficionado and robot addict
AKA: The guy with the yellow hat
FRC #5987 (Galaxia)
Team Role: Mentor
 
Join Date: Mar 2015
Rookie Year: 2012
Location: Haifa, Israel
Posts: 656
Ari423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud of
Re: Electrical Board for mecanum

Electrically, the only difference is each motor controller needs its own PWM (you can't use PWM splitters). Other than that, the difference is in the physical wheels and the programming.
__________________
2017-present: Mentor FRC 5987
2017-present: CSA for FIRST in Israel
2012-2016: Member FRC 423
2013: Programmer
2014: Head Programmer, Wiring
2015: Head Programmer, Wiring
2016: Captain, Head Programmer, Wiring, Manipulator, Chassis, CAD, Business, Outreach (basically everything)


  #3   Spotlight this post!  
Unread 22-07-2015, 13:00
GeeTwo's Avatar
GeeTwo GeeTwo is offline
Technical Director
AKA: Gus Michel II
FRC #3946 (Tiger Robotics)
Team Role: Mentor
 
Join Date: Jan 2014
Rookie Year: 2013
Location: Slidell, LA
Posts: 3,691
GeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond repute
Re: Electrical Board for mecanum

The biggest change to the control board would be to reflect that the four wheels must be independently driven. As such, a minimum of four motor controllers is required. If you put encoders on your wheels, you will need four, not just two. Quadrature encoders would require eight channels on the DIO, unless you're feeding back directly to the controller (e.g. Talon SRX).

Many teams which do mecanum also like to use "field coordinates" which allows the robot to go the same direction as you push the joystick, even if the robot is sideways or backwards. This will require an analog gyroscope to use the libraries.

If you only use pneumatics for shifting, this may go away; few team shift mecanum (apart from octanum style "shifting").
__________________

If you can't find time to do it right, how are you going to find time to do it over?
If you don't pass it on, it never happened.
Robots are great, but inspiration is the reason we're here.
Friends don't let friends use master links.
  #4   Spotlight this post!  
Unread 22-07-2015, 20:22
EricH's Avatar
EricH EricH is offline
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 19,817
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Re: Electrical Board for mecanum

Quote:
Originally Posted by GeeTwo View Post
The biggest change to the control board would be to reflect that the four wheels must be independently driven. As such, a minimum of four motor controllers is required.
That's not a change if you're already running a 4-motor drivetrain as many teams do, under 2015's R42. (Unless you're using "non-drivetrain" motors as drivetrain motors...)
__________________
Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons

"Rockets are tricky..."--Elon Musk

  #5   Spotlight this post!  
Unread 22-07-2015, 23:52
GeeTwo's Avatar
GeeTwo GeeTwo is offline
Technical Director
AKA: Gus Michel II
FRC #3946 (Tiger Robotics)
Team Role: Mentor
 
Join Date: Jan 2014
Rookie Year: 2013
Location: Slidell, LA
Posts: 3,691
GeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond reputeGeeTwo has a reputation beyond repute
Re: Electrical Board for mecanum

Quote:
Originally Posted by GeeTwo View Post
The biggest change to the control board would be to reflect that the four wheels must be independently driven. As such, a minimum of four motor controllers is required.
Quote:
Originally Posted by EricH View Post
That's not a change if you're already running a 4-motor drivetrain as many teams do, under 2015's R42. (Unless you're using "non-drivetrain" motors as drivetrain motors...)
Actually, it may be a bit of a change to the control board, as the wheels must be independently driven. If using PWM to drive your motor controllers, you must use four separate PWM ports, not two with wye cables. For the record, 3946 used two-CIM drive trains for both 2013 Ultimate Ascent (the only time we seeded top 24 at Bayou regional) and 2015 Recycle Rush (the only time we were picked for eliminations -- and we put our alliance over the top to go to CMP).
__________________

If you can't find time to do it right, how are you going to find time to do it over?
If you don't pass it on, it never happened.
Robots are great, but inspiration is the reason we're here.
Friends don't let friends use master links.
  #6   Spotlight this post!  
Unread 23-07-2015, 00:08
EricH's Avatar
EricH EricH is offline
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 19,817
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Re: Electrical Board for mecanum

Quote:
Originally Posted by GeeTwo View Post
Actually, it may be a bit of a change to the control board, as the wheels must be independently driven. If using PWM to drive your motor controllers, you must use four separate PWM ports, not two with wye cables.
I'm aware of that. For the record, that's not a change to the required number of motor controllers for the drive--which is what I was addressing--unless, as in your case, you're running a non-4-motor drivetrain. (Also note that CAN is not governed by the same rules as PWM, so if that is your setup, it's purely a mechanical and programming problem.) It's simply a wire routing, which should have little to no effect on the board (given that PWMs are small, light wires and there's almost certainly one going that route anyway, even if it is on a splitter for a tank-drive setup). The effect will be on the RoboRIO: namely, you have to use two more outputs for the drive motors.


There is one other change, though, that the OP should be aware of. Due to the mechanical aspects of the drivetrain, you'll have less space in the corners than normal, but if you can keep the mechanical crew from putting stuff in between the wheels, there may be more space on the sides of the robot to play with.
__________________
Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons

"Rockets are tricky..."--Elon Musk

  #7   Spotlight this post!  
Unread 23-07-2015, 12:22
FrankJ's Avatar
FrankJ FrankJ is offline
Robot Mentor
FRC #2974 (WALT)
Team Role: Mentor
 
Join Date: Feb 2011
Rookie Year: 2009
Location: Marietta GA
Posts: 1,944
FrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond reputeFrankJ has a reputation beyond repute
Re: Electrical Board for mecanum

Quote:
Originally Posted by Begather View Post
Yeah you are right. It is not possible.
What is not possible?

Space wise mechanum electrical doesn't take up much more than any 4 cim drive & less than a six cim drive. Granted it may have more wires. Our mechanum electrical board sits on the belly pan. With the Vex clamp gear boxes there is probably more room than we had with last years two speed six wheel drive.
__________________
If you don't know what you should hook up then you should read a data sheet
  #8   Spotlight this post!  
Unread 23-07-2015, 13:50
Ari423's Avatar
Ari423 Ari423 is offline
LabVIEW aficionado and robot addict
AKA: The guy with the yellow hat
FRC #5987 (Galaxia)
Team Role: Mentor
 
Join Date: Mar 2015
Rookie Year: 2012
Location: Haifa, Israel
Posts: 656
Ari423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud ofAri423 has much to be proud of
Re: Electrical Board for mecanum

Quote:
Originally Posted by FrankJ View Post
What is not possible?

Space wise mechanum electrical doesn't take up much more than any 4 cim drive & less than a six cim drive. Granted it may have more wires. Our mechanum electrical board sits on the belly pan. With the Vex clamp gear boxes there is probably more room than we had with last years two speed six wheel drive.
I think he meant it isn't possible to use PWM splitters like you might for a 4 or 6 cim tank drive. I definitely agree with you about the space requirement; our mechanum setup always takes less space than our tank drive setup (except for that one year we did 4 independently driven tank drive wheels which was a big mistake).
__________________
2017-present: Mentor FRC 5987
2017-present: CSA for FIRST in Israel
2012-2016: Member FRC 423
2013: Programmer
2014: Head Programmer, Wiring
2015: Head Programmer, Wiring
2016: Captain, Head Programmer, Wiring, Manipulator, Chassis, CAD, Business, Outreach (basically everything)


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 17:33.

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