Balls under a bridge

Take a look at this video: http://www.youtube.com/watch?v=HBwPsmAPN5M

The two robots on the coopertition bridge are balanced before the buzzer, but with about 5 seconds left, at least one ball becomes wedged under the bridge.

Per [G14] Strategies that use Basketballs to either aid or inhibit Balancing of any Bridge are not allowed.
Violation: Technical-Foul, and counting or discounting the affected Bridge as Balanced, as appropriate.

I believe that, in the case shown in the video, the bridge was already balanced before the ball entered, so the bridge would score like normal.

But, if the ball entered before it was balanced, and the robots took advantage of the presence of the ball to obtain a balanced bridge, the penalty would apply.

Watching scrimmage video, I see plenty of examples of balls under bridges not coming out like they are intended. I foresee lots of controversy when bridge balancing is achieved when there is a ball stuck underneath. If a ball is stuck under a bridge before balancing is achieved, is it possible to balance the bridge without benefiting from the stuck ball in some way?

I also heard reports of the balls not coming out from under the bridges. Hopefully the GDC saw this at the Week 0 events, and is going to modify the ramps a bit to help the balls out from underneath the Bridges.

The word “strategy” to me implies intentional placement of the ball, so I don’t believe there would be any problems with the rules in this case.

All they really need to do is put a short piece of netting attached to the bottom of the bridge that is weighted down on the other side with a piece of steel or iron (anything that keeps it in place, basically). It’s long enough to account for the bridge in any position and still keep the desired ball deterent barrier. If balls end up getting stuck in excess material now instead of the polycarb when the bridge is sitting naturally balanced, they would probably have to attach it to a roller of some kind that would retract the excess material without impacting the natural bridge balance. That would obviously be more difficult to tune without completely impacting the current bridge design…but it’s an idea that could be implemented, in theory.

I noticed this too. It is my hope that the refs look for ***INTENTIONAL ***use of the basketballs as aids.

I believe that they will ammend the rules, hopefully before week 1.

Keep in mind that any sort of netting they create would be an entanglement hazard for robots on the field. If it is at all lose, a robot driving by could get it caught up in its wheels. A robot trying to tip the bridge might drive to far and get its wheels, even momentarily, underneath the bridge before backing up to tip it, and could get caught.

I completely understand what you’re saying and this is probably the reason a fix this simple hasn’t been done and announced yet. I’m confident the general idea could be successfully implemented with some innovative tweaking, though.

The balls getting stuck was a huge issue at the week 0 event my team attended. Many team couldn’t climb the bridge with balls under it. I recommend lifting the bridge before climbing to clear out balls if you can.

In the case of balancing as long as you don’t intentionally place balls under the bridge I think they will let it slide.

Referees have been trained that balls will routinely end up under bridges, and that G14 only applied to conscious and strategic placement. This applies to both aiding and inhibiting of balancing.

I would not expect a “fix” for the bridges. They seem to be designed to release balls from under them when raised on that side](http://www.youtube.com/watch?v=-AMaqqmoLgQ&t=0m50s). Has anyone seen balls stay stuck when under a fully raised bridge-end? If so, this would seem geometrically very difficult–any idea how it happened?

Please note, if a ball gets stuck under both ends of the same bridge. The bridge may become totally disabled…

When one side of the bridge is lowered, the other side is raised along with the ball slope underneath, so it might manage to shake it out…hopefully

The polycarbonate is actually attached to the moving part of the bridge. So when the bridge is tipped it moves the polycarbonate and will dislodge the ball.

… Supposed to dislodge the ball.

In practice it’s not as efficient at dislodging the ball as it should be and sometimes needs the bridge to be held down on the other side longer than expected.