Bridge Question for those who have played

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Posted by Ken Patton at 03/04/2001 7:12 PM EST


Engineer on team #65, The Huskie Brigade, from Pontiac Northern High School and GM Powertrain.



At any of the regionals, did anyone observe the empty bridge "bouncing" from the down position to the balanced position after a robot crossed the bridge? This has happened on our practice field, in both directions, and I wonder if it is our field or if all of them do it....

Anybody see this happen before?

Thanks,
Ken

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Posted by mike oleary at 03/04/2001 7:20 PM EST


Student on team #419, rambots, from bc high and sponsors are overrated..go pocket-change robots!!!.


In Reply to: Bridge Question for those who have played
Posted by Ken Patton on 03/04/2001 7:12 PM EST:



i think that i noticed that happen a couple of times at the utc regionals but i could be wrong

: At any of the regionals, did anyone observe the empty bridge "bouncing" from the down position to the balanced position after a robot crossed the bridge? This has happened on our practice field, in both directions, and I wonder if it is our field or if all of them do it....

: Anybody see this happen before?

: Thanks,
: Ken

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Posted by Ken Leung at 03/04/2001 7:25 PM EST


Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.


In Reply to: Bridge Question for those who have played
Posted by Ken Patton on 03/04/2001 7:12 PM EST:



That used to happen to our practice bridge when we first built it. What happened was that we didn't put enough weight on the two pipes in the center of the bridge, therefore the bridge tend to stay in the balanced position.

There are supposed to be 18 lbs on each pipe, so there are total of 36 lbs on both. When the bridge is at the down position, those 36 lbs with the long moment of the pipes are going to keep the bridge down. It even worked with only 30 lbs for us.

Another source of this problem might be that the two steel L bracket around the 4x6 might be too close to each other that it's squeezing the 4x6 too hard, and that keep the bridge in the balanced position. But this is not likely...

So, check and see if you have enough weight on the pipes, if the pipes is long enough, if you have the steel lips at the end, if the bridge is long enough, if you have enough wood piece under the bridge... etc.

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Posted by Tom S. at 03/04/2001 7:52 PM EST


Student on team #177, The Bobcats, from South Windsor High School and International Fuel Cells.


In Reply to: Bridge Question for those who have played
Posted by Ken Patton on 03/04/2001 7:12 PM EST:



I can affirm this. The bridge had a tendancy to stay 1-2" off the ground, unless it was forced to the floor. The bridges in competition most definitely do not have the 3 "balance" points as mentioned at kickoff. I talked to the field manager after the finals, and she said that the problem was too much friction on the angle irons. This is the way the field was constructed at New England, and it will be the way it is constructed everywhere else she said.

The 1-2" of space caused some teams problems (including us) when trying to push goals onto the bridge. The weights were correctly added, it was just a friction problem. This "Problem" has actually made it easier for some teams to balance on the bridge since there is more friction.

An unrelated comment about the bridge, a lot of teams seemed to be having traction problems on the bridge, I'm not sure if there was some difference in the carpeting or something, it seemed to be the normal FIRST carpet.... not sure what was up with that.

Tom Schindler
Team 177

FIRST said that this is the way they construct the field, and it is going to be like that at all the competitions. So drivers: be prepared to have a little lip on the bridge...

: At any of the regionals, did anyone observe the empty bridge "bouncing" from the down position to the balanced position after a robot crossed the bridge? This has happened on our practice field, in both directions, and I wonder if it is our field or if all of them do it....

: Anybody see this happen before?

: Thanks,
: Ken

[archiver]

Posted by Jason Rudolph at 03/04/2001 9:29 PM EST


Other on team #459, Rampage, from University of Florida/Eastside High School and .


In Reply to: Re: Bridge Question for those who have played
Posted by Tom S. on 03/04/2001 7:52 PM EST:



: An unrelated comment about the bridge, a lot of teams seemed to be having traction problems on the bridge, I'm not sure if there was some difference in the carpeting or something, it seemed to be the normal FIRST carpet.... not sure what was up with that.

Well, I am assuming the same thing happened at UTC as it did at KSC. At KSC, due to all the traffic on the bridge, many robots with LOTS of traction, and robots falling on it, by the end of the first day, the bridge had a few "slick" spots on it where the carpet had been damaged. In one round, our robot hit a spot, and skid right off the bridge towards one side, and got caught on it. All I can say, is be ready for anything.

Jason

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Posted by Andy Baker at 03/04/2001 11:52 PM EST


Engineer on team #45, TechnoKats, from Kokomo High School and Delphi Automotive Systems.


In Reply to: Bridge Question for those who have played
Posted by Ken Patton on 03/04/2001 7:12 PM EST:



Ken,

It seems like your 'bot is going too fast over the bridge. The faster that bridge falls, the higher it bounces up. If you are making the bridge bounce, you are going pretty fast.

You just gotta slow down, my boy. Try not to get too much air. Just what is the speed limit in Michigan?

I guess we'll find out soon.

Andy B.

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Posted by mike oleary at 03/05/2001 12:10 AM EST


Student on team #419, rambots, from bc high and sponsors are overrated..go pocket-change robots!!!.


In Reply to: Bouncin' bridge = fast robot
Posted by Andy Baker on 03/04/2001 11:52 PM EST:



hehehe...speed limits are funny jokes, at least in boston they are...cuz in boston its normal to honk and yell at people for being too slow when when theyre already speeding
mike who amazingly hasnt gotten a single speeding ticket

: Ken,

: It seems like your 'bot is going too fast over the bridge. The faster that bridge falls, the higher it bounces up. If you are making the bridge bounce, you are going pretty fast.

: You just gotta slow down, my boy. Try not to get too much air. Just what is the speed limit in Michigan?

: I guess we'll find out soon.

: Andy B.

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Posted by colleen - T190 at 03/05/2001 12:32 AM EST


Engineer on team #190, Gompei, from Massachusetts Academy of Math and Science and WPI.


In Reply to: Bouncin' bridge = fast robot
Posted by Andy Baker on 03/04/2001 11:52 PM EST:



It's nice to know that your robot can handle it though...

In the semi-finals.. we were going over in tandum with a robot who would drive back over once we were set to reset the ramp for our partners...

However, they started driving back before we were off the edge.. yeah.. we drove off with the ramp a good 8-9inches up at least...

And we keep on driving.. and doing our thing.. it's great

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Posted by Ken Patton at 03/05/2001 9:38 AM EST


Engineer on team #65, The Huskie Brigade, from Pontiac Northern High School and GM Powertrain.


In Reply to: Bridge Question for those who have played
Posted by Ken Patton on 03/04/2001 7:12 PM EST:



thanks everyone for your experiences....

Andy, at first I thought that was it, but a couple of times it happened when we weren't going super fast (in fact we were towing the near side goal over with us).

Plus, I HATE telling the drivers to slow down, it just doesn't seem like the right thing to do.... )

Here in Michigan, the speed limit is 70. I know this for a fact bacause I got my first speeding ticket in about 8 years just the other day. Michigan State Trooper got me with laser... ouch.

Ken

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Posted by Andy Baker at 03/05/2001 10:22 AM EST


Engineer on team #45, TechnoKats, from Kokomo High School and Delphi Automotive Systems.


In Reply to: thanks to all
Posted by Ken Patton on 03/05/2001 9:38 AM EST:




: Michigan State Trooper got me with laser... ouch.

I know what you mean, those Michigan Troopers are tough.

I got a ticket on the way home from being a referee at the Ford Sweet Repeat last fall... ouch.

Andy B.

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Posted by mike oleary at 03/05/2001 2:11 PM EST


Student on team #419, rambots, from bc high and sponsors are overrated..go pocket-change robots!!!.


In Reply to: I feel your pain, Ken
Posted by Andy Baker on 03/05/2001 10:22 AM EST:



yeah the closest i came was when i got pulled over and told i should go a little bit slower cuz i was passing somebody so that i could make the exit that was 35 or so feet ahead...said next time i should go behind the guy...didnt comment on the fact that i was doing 85 on a 50......

:
: : Michigan State Trooper got me with laser... ouch.

: I know what you mean, those Michigan Troopers are tough.

: I got a ticket on the way home from being a referee at the Ford Sweet Repeat last fall... ouch.

: Andy B.

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Posted by Chris Orimoto at 03/06/2001 3:00 AM EST


Student on team #368, Kika Mana, from McKinley High School and Nasa Ames/Hawaiian Electric/Weinberg Foundation.


In Reply to: Bridge Question for those who have played
Posted by Ken Patton on 03/04/2001 7:12 PM EST:



Yep...the exact same thing happened to our practice bridge. I saw it happen at the KSC Regional too. And Andy is right, this does seem to happen whenever a robot goes too quickly over the bridge. However, I also have to agree that telling the drivers to slow down just seems wrong. Therefore...what's the solution? Honestly I have no idea...but we TRIED to remedy this by adding an arm that is specifically designed to quickly push the bridge up or down when it hits that "balanced" after someone comes off.

Just my personal thoughts...

Chris, #368

PS: WOW, speed limit in Michigan is 70??? In Hawaii, it's only 55...