So where does 1114’s ramp fall in the rules of ramps and tethered robot parts?
https://www.youtube.com/watch?v=pzeSsgWorFI
At first I thought they just replaced their 3rd alliance member with a ramp.
wait is that tethered?
It does not appear to be. Could be small enough to not be seen by the camera though. The ramp is completely passive however, the human player tips it down with the noodle.
I only saw 2 robots on that side. Could the ramp be a 3rd robot?
Its not a bad Idea to have a ramp on hand and have teams put their number plates on it if there are any issues getting their robot to the match Maybe even bringing a printer to the competition
Being part of the robot, the ramp must follow all robot rules and fit into transport configuration.
I would suggest a passive design; if your robot is able to function without the ramp’s help, a tether takes up too much field space… if you’re going for a FRC 148-esque design, then the tether might make sense
Does a ramp have the minimum features to qualify as a ROBOT?
Think of it more as a part of the robot and not as a robot itself.
That seems to indicate that if it’s not carrying power or signal it’s not a tether.
I think we need to come up with a new term for a robot tied to a ramp with a string rather than using tether.
If you want to be really specific the word tether in the English language has absolutely no reference to a attachment wire that provides power to another object. Both tether and leash are defined as cables used to limit a domesticated animal’s range of movement. It’s not exactly confusing to use the word tether to describe methods of attachment ether powered or not interchangeably.
Funny enough. We use a COTS retractable dog leash as our tether for our ramp. $10 from a local pet store.
Wire or cable is not a good idea in my opinion since it has memory and won’t want to lay flat.
As I said in a previous post I recommend Mason’s line It is a strong string and is available in florescent colors so it is highly visible and it will lay flat so the entanglement hazard is low. http://www.homedepot.com/s/mason’s%20line?NCNI-5
We did some testing at GTR-C with a tethered ramp. Thin aircraft cable was less prone to getting caught in our wheels than 3/16 nylon rope. We made a ramp from pink panther insulation foam, it was not particularly durable but it only weighed a pound and worked just fine.
I can’t find anything on those brands indicating their rated loads. Do you have any source that might list that? We found that we need higher than 80 lb rated load for an application, and I don’t know whether or not I can trust Masons Line.
I suggest you try Braided Fishing line like http://www.amazon.com/Power-Pro-2110065050-Parent-Microfilament-Line/dp/B005ADORGK.
In my experience it’s breaking point is well above its rated load. Just make sure you use the right knot, the “palomar knot” is recommended for braids.
I wouldn’t.
Not for the breaking strength, but for the visibility factor. 35 thou or so isn’t all that easy to see, particularly from the edge of the field. You’d want to make fishing-line rope with it just for visibility. Remember, if the refs can’t see the tether, we may be doing some investigating after the match to make sure the tether is actually present and is actually in one piece. That’s going to take a while… Particularly if for some reason we decide that we need to check after every match.
I’ve seen some nice elastic-y cord, as well as nylon webbing. I might–if I was y’all–look at some light kernmantle-type rope. Not climbing-weight, mind you, but something on the order of shoelace size. It can be a smidge on the heavy side, but it’s plenty strong.
Did you notice the color linked too is High Vis yellow before you commented?
Also, assuming the “we” in your comment is the refs; that is your decision on whom to give additional scrutiny, just don’t penalize them for your ridiculous decision. It should be pretty easy to determine if the tether is in place.
High Visibility Yellow, at .035" thick. On carpet. From a distance. Think about that for one moment.
Is it going to be visible? Yeah. Is it going to be easily visible at close range? Yeah. Is it going to be easily visible at 15 feet? 20 feet? 50 feet? How about 150 feet (somewhere in the audience)? Not so much.
And because it’s not as easily visible as, say, mason’s line, the refs–even if they can see it clearly–are going to have people asking “isn’t that a penalty?” to which the response will have to be–every match–“No, because there’s a tether there” (and a quick-thinking ref will hopefully check the tether after every match just to make sure it didn’t snap). Remember, if you make something obvious, the refs are a lot less likely to have to take time to make a judgment call (BTW, we don’t like making judgment calls if we don’t have to). If you make it non-obvious… well, it could go either way. Chances are that you’ll be asked nicely to see if there’s any way to make it more visible.
For example, I think it would be a lot easier to see if someone were to apply a rope-making machine to the line and turn 1 strand into 6 or so strands all tightly woven together.
Also, assuming the “we” in your comment is the refs; that is your decision on whom to give additional scrutiny, just don’t penalize them for your ridiculous decision. It should be pretty easy to determine if the tether is in place.
It is. Realize this: It should be easy to determine if the tether is in place. Yes, I agree. It may be LESS easy to determine that it is still in one piece! And if it is not in one piece, we’ll probably start with a suggestion to use a stronger tether if possible (assuming that such multi-piece-ness was accidental), and only start going for stronger “suggestions” if it happens again.
Because remember: If you can “get away with not following” a rule (here I’m aiming at the perspective the rest of the teams may be seeing from, and giving us a hard time after or during the event from), there are other teams that may be, shall we say, a little “less accidental” about “not following” a rule, and then you’re the “well, they got away with it” team used as an example by said teams. I don’t like those kind of situations, as a spectator OR as a ref!
It is legal or not? Without clear rules to the contrary, if the refs decide to penalize a team because it inconveniences them because it makes them answer questions from the crowd (like that happens); then that is against the intent of Franks message here http://www.usfirst.org/roboticsprograms/frc/blog-dallas-regional-final-matches-resolution
BTW, 80LB power pro, does not snap unless you have a serious fish on the line, a 120 LB robot doesn’t stand a chance.
I agree.
But let me ask one simple question. Let’s assume that you see a ramp, on the far side of the field from your team, with no apparent tether to its parent robot. What is your assumption, and how does that affect your experience?
Now, I know in FRC, many people (like you and me) will go “Oh, they found something hard to see as a tether” and go ask the team questions, and learn something new. But others (I make no assumptions on actual involvement level) will probably assume that the team is being allowed to slide past the rules, and the logical conclusion from that (flawed) assumption is that teams are getting away with cheating (I’m assuming, that they don’t go talk to the team in question, or the officials, for some reason). Does that help their team experience?
I submit that it doesn’t help that individual’s team’s experience, partly due to “one sour apple”. And there’s nothing the officials can do about it if the team doesn’t ask questions to clarify. That’s a shame.
So by making a somewhat visible tether even more visible, you actually improve the team experience, without the various officials getting involved at all. Just a thought. (And it helps the refs out–see tether, know that tether is/isn’t wrapped around tote/robot/container, makes it easier to score–and makes it much easier to avoid getting snagged after the match if it’s misbehaving.)
BTW, 80LB power pro, does not snap unless you have a serious fish on the line, a 120 LB robot doesn’t stand a chance.
Just out of curiosity, how well does it do when run over by mecanum wheels or inadvertently snagged in a drivetrain? Tensile strength and shear strength aren’t entirely the same… I’m guessing you’ve run a couple of tests? I highly recommend doing a quick strength/snag test if one isn’t sure of how a tether will hold up, if there’s a robot available.
It not getting tangled is a big deal. Because if it gets tangled it has the potential to ruin a wheel, and render our robot and our partners robot useless for the match.