FRC488 Driving Over the Bump

[waialua359]

Originally Posted by =Martin=Taylor=

Wow. That’s really scary. I'm surprised so many people are planning to 'brute force' the bump like that. Even if your CG never goes outside the footprint the sheer momentum of your robot pitching forward may be enough to tip it.

If you left larger gaps between the wheels the transition would be smoother.

Sure, but with practice, the drivers can really get comfortable with it and do it relatively well every time. We must have done it similar to 488 over 30+ times daily with no problems yet.
Adding a little traction control can help things a little also.

[MrForbes]

We got ours going over the bump after some weight redistribution.

http://www.youtube.com/watch?v=3NGVs1QOPGQ

[dtengineering]

Has anyone considered putting rubber grommets around their axles where they mount to the frame to reduce impact forces slightly? They'd have to be pretty stiff to keep the chains from coming off, but 1/8" of "give" on a high impact would be a good step towards shock reduction.

Jason

Edit: "Brute force the bump?".... YEAH!! I want to see robots get air off those things! There's going to be more than one team who drives over them at high speed just for fun! I'm going to watch some old Dukes of Hazzard reruns for inspiration!

[Tony.Wu]

Wow that's alot of placation wheels there! Great work!

[MrForbes]

Originally Posted by dtengineering

Has anyone considered putting rubber grommets around their axles where they mount to the frame to reduce impact forces slightly? They'd have to be pretty stiff to keep the chains from coming off, but 1/8" of "give" on a high impact would be a good step towards shock reduction.

I guess that depends on how your axles work, ours are welded to the frame (cantilevered dead axles) so that might not work. We could make part of the frame support the drivetrain, and have it isolated from the rest of the frame.

Might be easier than trying to convince the driver to slow down for the speed bump

[larrysz92]

Nice Thanks 4 the info

[Chris is me]

Thanks a lot for posting these videos. It's allowed me to evaluate and consider the forces involved in climbing the bump on the rest of the robot before our chassis got built. This is the year of the 8 wheel drive!

[Madison]

More videos:

A frame stiffens things up and reduces bounce:
http://www.youtube.com/watch?v=haepKMB27Xg

Over the bump, onto the ball:
http://www.youtube.com/watch?v=2f3-ZACejA8

[Cyberphil]

Very nice! Great job guys! Its good to have another KISS thinking team!

[Joe Johnson]

Originally Posted by Madison

More videos:

A frame stiffens things up and reduces bounce:
http://www.youtube.com/watch?v=haepKMB27Xg

Over the bump, onto the ball:
http://www.youtube.com/watch?v=2f3-ZACejA8

I love the one where you go right over the ball like it isn't even there.

My sister's husband told me when I was just a wee one, "momentum will take you where traction will not."

Struth.

Joe J.

[Chris is me]

Will going over a ball like that be a penalty? That will be extremely annoying, since they are pretty much impossible to see.

[dtengineering]

Originally Posted by Chris is me

Will going over a ball like that be a penalty? That will be extremely annoying, since they are pretty much impossible to see.

Good question, and with proper deference to the Q&A as the appropriate forum to get a "real" answer, my guess would be "no" as the ball has not entered 3" into the robot. There have been some Q&A answers regarding using ramps on the top of the robot to direct the ball... which is allowed, as long as the ball doesn't penetrate 3" into the robot, so presumably the underneath of the robot would be the same.

Jason

[waialua359]

Nice post Madison.
We are not as brave to "Dukes of Hazzard" our robot, yet!