pic: New low bar flaps

[Mr V]

Originally Posted by Chris is me

I don't know, using bumper fabric for low bars didn't make the obstacle entirely different, except for the part where bumper fabric was far less prone to ripping apart. If anything buying a few yards of fabric seems easier for most events to do than getting strips of vinyl cut and zip tied together. I really don't get why FIRST went this route.

I'm especially troubled by the early reports that this vinyl makes the low bar effectively shorter. Making the biggest design constraint in this game even tougher, long after we're finished with our robots, instead of "just" buying tougher fabric? For once I'm glad I competed Week 1 and not Week 2!

With McMaster's incredible distribution system the events did not have to obtain the vinyl strips, they were drop shipped, presumably to the organizer of the event. They can be implemented with the tools in Case 8 so that they are identical across all events. The availability of fabric locally may be hit or miss and FIRST probably couldn't find a supplier that could ensure that almost all of the 21 events being played this weekend received it in time. It would also require a sewing machine at the event and it really needs to be a heavier duty unit to stand up to sewing the bumper fabric consistently.

Consistency is a huge part of this and having the field supervisor cut the roll into specific lengths and drill a couple of holes at a specific point is something that should be relatively consistent.

Are you basing the thought that it reduced clearance a statistically significant amount on actual match play reports or what has been postulated here? Ditto for the hypothesis that a human player can bowl the boulder through it. Personally I've only seen speculation about that and not verified proof of either. Yes the 4mm thickness of the freezer door is more than the cloth but it is certainly within FIRST standard of tolerance that teams should have designed around. The freezer door material is quite heavy and semi rigid. With two strips I doubt the mass of the boulder is high enough to break completely through properly positioned flaps unless you've got a really really strong bowler.

For those teams that are complaining that the flaps could damage their camera I have to ask, did you plan for protecting your camera from the missed high goal shot that may land on your robot? For those that the flap causes their ball to be dislodged from its position I have to ask did you design your robot in such a way that the ball is not dislodged from going over the rougher defenses or against rough defense? I have a hard time imaging a situation where the flap sliding across the camera would damage it while a boulder falling from a couple of feet wouldn't. Ditto for dislodging a ball, if a flap can dislodge it what happens when crossing the rock wall, moat, chilli fries or ramparts at speed?

I know for my team I insisted that the camera be located in a manner that it would be protected against a boulder that may land on the robot. Another requirement was that the robot maintain the ball in the ready to shoot position despite an unusually rough defense crossing or a high speed impact. I also insisted that the robot be designed to clear the low bar if for some reason it was 1/2" lower than the dimensions on the official field drawings. So for us I don't see it as an issue but we will find out tomorrow.


For the record our robot was designed with the knowledge that the official fabric was not highly robust. So we tried to minimize any potential damage to the fabric so that we weren't at risk for a penalty for damaging or repeatedly damaging the field.