View Single Post
  #4   Spotlight this post!  
Unread 19-01-2013, 23:49
StevenB StevenB is offline
is having FRC withdrawal symptoms.
AKA: Steven Bell
no team
Team Role: College Student
 
Join Date: May 2005
Rookie Year: 2005
Location: Stanford, CA
Posts: 412
StevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond repute
Re: paper: Mecanum: we can't even agree on pronunciation?

Since I've been one of the people apparently spreading misinformation, please help me work through this. The part I have trouble with is this statement:
Quote:
Originally Posted by Ether View Post
A mecanum wheel generates 41% more driving force than an omni wheel driven by the same torque
Suppose I have robot with four omniwheels mounted diagonally on the corners. To strafe diagonally, two of the wheels drive, and the rollers on the other two spin freely. In this direction, the driving omniwheels act exactly like solid wheels, since motion is parallel to the roller axis. Applying a torque of "1" to these wheels should produce a force on the robot of "1".

If a mecanum drive robot is strafing diagonally, again, two of the wheels drive, and the rollers on the other two spin freely. If the statement above is true, then applying the same torque of "1" will produce a force on the robot of 1.414. This would all make sense if the mecanum wheel had a smaller effective radius (specifically, 1.414 * pi * r). That's precisely what I see in your video with the 8" kit wheel and 8" mecanum, but it's not what I'm reading in your document. What have I missed?

PS - I may have missed something in your document, since I don't have Word and the diagrams are showing up all garbled. Any chance you could post a PDF?
__________________
Need a physics refresher? Want to know if that motor is big enough for your arm? A FIRST Encounter with Physics

2005-2007: Student | Team #1519, Mechanical Mayhem | Milford, NH
2008-2011: Mentor | Team #2359, RoboLobos | Edmond, OK
2014-??: Mentor | Looking for a team...

Last edited by StevenB : 19-01-2013 at 23:57.