Problem with Lowering the Bar

One thing FIRST might have overlooked:

The bar can be lowered after a match so that robots can be removed easily. If you have just a hook, you can lift your robot straight up and carry it (which will be very awkward) off the field. Then you can tether and lower it to fit through doorways and such. If you have a locking mechanism on your hook so that you can’t be knocked off the bar (a simple spring latch), you can’t reach it to open the latch and lift your robot. The bar is lowered to where you can reach it…but if your robot is only a couple of inches off the ground, that bar can’t be lowered more than a couple inches. The whole system would get jammed and either ruin the mechanism, the robot, or both.
The simple solution is to swing your robot around the bar so the bar can be lowered - this will take at least three people per robot (two to hold the robot steady, one to release the mechanism and catch that half of the robot) which is not a big deal. If there are 4 bots on the bar and on top of one another in a big mess, this is going to take time to sort out and get taken care of. Here is where the problem comes in. If your robot is only off the ground an inch or so, there will most likely (depending on the position of the hook relative to the robot - edge or middle) not be enough rrom to swing your robot clear of the platform. If there is one bot like that, there could be other bots stuck 3’ off the ground. Now we have to find ladders and take great care not to fall off the ladder, not to get crushed by the robot, and whole mess of other things. I’d say this situation won’t be common, but you never know.

NOTE TO FIRST: Have ladders on hand at the arena!

Note to teams designing a mechanism such as the one described above:

Design your locking mechanism so that it may be unlocked by someone standing on the ground via pulling a string, or other method which does not require the robot to be enabled.


Perhaps an update mandating the prevention of such occurance is in order? It is possible that rookie (and likely veteran teams also) could overlook this possibility and have a rigid structre.

I think the FIRST crew needs to make sure that everyone knows about this, not just readers of CD.

I’d have to agree with what’s been said.

It would be a very good idea if FIRST also publishes this in an update.

Just as in 2002, if you couldn’t detach your robot from the goals, you got DQ’ed. If you design your robot this year so that it can’t use the bar-lowering to release it, well then… that wasn’t very good engineering now was it? :wink:

either design a sting release mechanism, avoid this system, or make a collapseable “arm” since the bot and only be 60" tall, it needs to be telescoping anyway, just make it so you can manually collapse it when on the field

Also keep in mind that you CAN power up your robot on the feild afterthe match. you could simply power up and reverse the mechanism or whatever is needed… if it is a pneumatic mechanism simply throw the release valve…

It’s like those crazy physics teacher always said… “What goes up, must come down.”

Can you power up? Tethering on the field between matches has been greatly discouraged the last few years and I’d find it very surprising that tethering is allowed now. I suppose if thats all that can be done, then it would have to be allowed. But if someone has found something in the rules that says tethering is expected and accepted, I wouldn’t rely on that as a solution.

There are many ways to solve this problem…but it is an issue that some teams will probably not take into consideration if they are not made aware of it.

Rule <T05>.

WEll i remember that the hooks from the game two years ago were very passive systems that latched on and wouldn’t let go… others were actually so sturdy that there was no way to remove them other than powering up… yes it is dicouraged but if u think about it, in the amount of time that it takes to lower the bar (if you seen it takes a while for that thing to come down), you definitly could be tethering up and retracting…

If I remember correctly, during the kick-off, Woodie said that the bar can be lowered if a team needs it. So if you have a simple hook that doesn’t latch onto the bar, then the bar doesn’t need to be lowered to get your bot off the bar and it won’t be.

unless i’m mistaken, this is a circular bar, why not lift up the robot so as the bar comes down, so that when the bar is all the way down your arm is perpendicular to the floor

this probably doesn’t make sense to anyone but me, but as i see it, there is no problem :rolleyes:

because the robot has width, and would not be able to rotate, it would hit the floor

My only concern is that it is built to handle a beating. I hope the cable lifting mechanism is strong enough to hold 390+ pounds ( 3 robots)

The Bar is going to take many hits and abuse from robots

If the bar decides to come down there are going to be 2 or more unhappy teams with damaged robots…

I think FIRST would be able to use common sense, and know when to stop for robots to get off, and be able to decide whether or not they need to keep on going for others.

Well, as stated above T-05 seems to resolve all issues with this problem, so let this be a lesson to everyone - READ THE ENTIRE RULEBOOK BEFORE YOU POST SOMETHING AND LOOK FOOLISH LIKE ME :smiley: