Thread: How Do mecanum wheels handle the bumps?
View Single Post
  Spotlight this post!  
Unread 29-03-2010, 12:30
Ether's Avatar
Ether Ether is offline
systems engineer (retired)
no team
  
Join Date: Nov 2009
Rookie Year: 1969
Location: US
Posts: 8,100
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: How Do mecanum wheels handle the bumps?
Quote:
Originally Posted by JesseK View Post
Again, the assertions assume the rollers pit all of the force forward. The reality is that the rollers, even when not spinning, will put part of the force inward toward the robot. The force vector calculations easily show this. The resulting forward force is based on the fact that one component of both force vectors faces the other side of the robot; these two components cancel each other out. The forward component of the force vector is what pushes on the hypothetical wall.
http://www.chiefdelphi.com/forums/sh...6&postcount=33

Refer to RobotA mentioned in the thought experiment in the post at the link shown above.

If the motor is providing a torque of 40 in-lbf to a wheel, and the wheel is not slipping, then the carpet MUST be reacting with a force of 10 pounds (for a 8" diameter wheel) in the plane of the wheel, acting against the wheel trying to push it forward. The forward component is 10 pounds (the exact same forward component you would get with a standard wheel). It cannot be otherwise.

And yes, with the mecanum wheel there are additional vector forces at play. But they do not subtract from the 10 pounds. I encourage those of you who are using the "vector" argument to think a bit more about how the vectors are created.


~