Hinged Bumper Design?

[phrontist]

Does anyone remember that robot with bumpers on hinged arms that could stop other robots dead in their tracks? A video was posted to chiefdelphi either last year or the year before...

[Adam Richards]

Are you talking about the robot in 2003's Stack Attack?

[phrontist]

Originally Posted by Adam Richards

Are you talking about the robot in 2003's Stack Attack?

Possibly. I don't know what year it was from. The bumpers would sort of retract when hit and use the force of the attacking robot against it, providing more normal force. It was a brilliant design.

[RogerR]

Originally Posted by phrontist

Does anyone remember that robot with bumpers on hinged arms that could stop other robots dead in their tracks? A video was posted to chiefdelphi either last year or the year before...

i believe you're refering to team 694's (stuypulse) 2005 machine. there's a thread, but all the links are broken. i do have one of their promo videos, which shows the bot shifting, but its too large to upload.

[phrontist]

Originally Posted by RogerR

i believe you're refering to team 694's (stuypulse) 2005 machine. there's a thread, but all the links are broken. i do have one of their promo videos, which shows the bot shifting, but its too large to upload.

That's it! If anyone could get me a copy of those videos, I'd be extremely grateful: bjornw AT gmail.com

[Billfred]

I've uploaded it:

http://www.billfredinthenighttime.com/694.wmv

[Nuttyman54]

wow...i'm always so impressed with the fast response on these forums. within 6 hours phrontist has a link to his video....this can only happen because of how involved the FIRST community is...gracious professionalism at work folks!

[Zach Purser]

Wow, that's beautiful! I drew up designs for a similar bumper about 4 years ago but we have never been able to make it due to weight. It's beautiful to see that the design actually works. Maybe we can revisit that plan again this year.

[ClintDog]

That is truly beautiful..... i am impressed!

[Billfred]

Can anyone explain how it works and what the benefits are? The video was interesting, but I couldn't quite figure it out.

[Nuttyman54]

if you're talking about the bumper, it works by utalizing the total impulse: by collapsing, it keeps the force at any given time point low, so that the friction from the wheels can keep the robot from moving. quite ingenious really

[Tim Delles]

If you also look at the video, the bumpers act as a force that lifts the front of the "attacking" robot, which shifts the direction that the robot is moving. It also looks like it lifted that robot just enough to bring all of the wheels off the ground, which would complete destroy an "attacker" robot.

Good job guys, it looks like a great idea.

[phrontist]

Originally Posted by Nuttyman54

if you're talking about the bumper, it works by utalizing the total impulse: by collapsing, it keeps the force at any given time point low, so that the friction from the wheels can keep the robot from moving. quite ingenious really

I question this analysis. Assuming the robot is going as fast as it can go before impact (the worst case scenario), the force being exterted by the robot is the same as long as it's on the ground. This lessens the impact by transforming that force the robot is exerting through it's drive train and moment into upward movement, causing it to lose contact and limiting it's pushing power. As soon as the attacker makes contact with the bumper, it's now adding to the normal force between bumper-equipped robot and carpet. All of it's pushing efforts are used against it, It's really very zen.

[Nuttyman54]

i think it utalizes both ways...i re-watched the clip and saw it actually lift up this time (i didn't see that last time, i thought it just collapsed)

[Conor Ryan]

Originally Posted by phrontist

I question this analysis. Assuming the robot is going as fast as it can go before impact (the worst case scenario), the force being exterted by the robot is the same as long as it's on the ground. This lessens the impact by transforming that force the robot is exerting through it's drive train and moment into upward movement, causing it to lose contact and limiting it's pushing power. As soon as the attacker makes contact with the bumper, it's now adding to the normal force between bumper-equipped robot and carpet. All of it's pushing efforts are used against it, It's really very zen.

Yeah, thats exactly what I was thinking about it. Its a defensive mechanism, so once something is driven (or it drives) into something, that inital force is absorbed. And then the collision follows as it would have if the spring wasn't there.

The reason though why this is abvantagous particularly in the 05 is game is that it eliminates all of the minor forces that would push up on the robot. Particularly those minor ones that throw you off when you are about to cap.