In #3 you mentioned how everything is dominated by friction, and it is unfair to characterize a type of robot as weaker.
Then, in #4 you went on to say how a robot on the HDPE has less traction than one on the mesh... It's just like you said above. A robot that gets a 1.2 coeff on the HDPE will beat a robot that gets a 1.0 coeff on the mesh... the mesh is easier to get a good "grip" on, but there are plenty of teams that have taken the time to "grip" the HDPE just as well, or better.

I think it will be harder than most people realize to "unseat" robots from the top of the ramp. Or at least the ones that have designed to stay up there. Even if you can dislodge a robot from the top, that doesn't necessarily mean you can get on top yourself.

I can't wait to see some of the epic battles for the HDPE.
FIRST truly has made a game that is more audience friendly. Falling boxes, loud noise, robots colliding.

Just $.02

Keep in mind the previous comment comes from the team leader of 229. Who's bot at this point has a set of wings that deflect a bot trying to push it. They have video of just the wing and a bot drives right up it until it gets hung up at the top. Its simply beautiful. After you see the video you'll understand why he said it will be hard to unseat rampdoms, at least his.

GregT: I don't see how its an unfavorable angle, As the bot comes up the ramp at a 14degree angle it can't push completely laterally whcih means some energy goes into an upward force. How a stacker is going to gain 40 lbs from carrying crates is beyond me, unless they hold 8 of them in a nice stack. But those 40lbs would be a few feet in the air, raising there CG. A slight bump from the rampdom would send it tumbling down the ramp. As for your generaliztions about tankdrives some of it is true but then there are teams like 45 that have tank drives that will excede the majority of wheel drives out there. As for matches without stacks, from all I've heard about scrimmages the tallest stack is a 4 human stack. Finally it seems people are under the assumption HDPE is slippery but there a materials that have VERY high COF on it, some 2 to 3 times the numbers John gave.

The mesh has texture, the HDPE does not. You can't grip the HDPE, the most you can hope to do is increase your normal force with a suction cup (and I don't think the HDPE will be in good enough shape to allow this to work as well as some teams think it will).

sevisehda: I said upwards of 40 lbs, I agree that its unlikely someone will be able to carry 8 stacked bins. I do think the angle helps the robot going up the ramp, its hard to tell though. Regradless, most robots will be able to push most other robots off the top of the ramp. I doubt any robot can withstand the force of 2 other robots trying to push it off the HDPE. Only time will tell.

Greg

You can't grip the HDPE, but you can still get increased traction with the right tread material. Using the right type of wheels can dramatically increase your traction.

HDPE DOES have traction!
Did you guys do ANY experimentation? We have materials that get better coefficient of friction on HDPE than on Carpet!
Neoprene for example... it is capable of getting a mu of upwards of 3 on the HDPE. Now imagine, a robot that puts 400+ lbs of normal force on a coeff of 3. (let me do the math for you) it will take 1200lbs of linear force to move them! You call that "easy to push"?

Can your robot push with that much force? Even with 100 bins you can't do that...

There will be numerous robots that can stick to the ramp, and withstand an attack from multiple other robots.

I think your assumptions about the game... AND about the laws of physics are flawed. I think this game will surprise you, in BIG ways.

By grip I ment traction. Yes, if you use a suction cup to pull down and put that much force on your wheels, you will be very hard to move (unless you have un-anchored arms and torque comes into play).

From the robots that I've seen thus-far, it seems like many teams try to hit all of the boxes during the autonomous mode. I was just wondering... do you guys always try to get all of the boxes? What happens if two of these bots are alliance partners? Do you guys control each "wing" independently, or do you expect only one bot to go for the wall?

It also seems like this tactic is self-defeating during the qualifying rounds. In one situation, a koth bot would get 29 bins on their side, and end up with a 2 stack, while the opponents have a 2 stack with their human player boxes, which would give the winning alliance 114 (2*35+25 + 2*[2*6]) QPs.

Yet, in another situation, the koth bot would only take 17 boxes, leaving 12 for the other alliance. If koth bot's alliance gets a 2 stack and allows the opposing alliance to get a 3 stack, the winning alliance would get 173 (2*23+25 + 2*[3*17]) QP's. I mean, all stacks being equal, each box is worth twice as much in the losing alliance's scoring zone for the winning alliance. Why the need for a massacre?

Greg

Thank goodness - someone who has actually started to THINK about how to play the game!!!

Teams - particularly rookie teams that may not have run into this type of play in prior years - need to get used to the idea that what matters in this game is the QP score and not the "game score." Folks need to understand that decimating an opposing alliance is a BAD IDEA. Yes, you may win the match. But your QP score will be lower than a team that lets the opposing alliance get a good score (just not quite so good that they win!).

Yes, you can wipe out a high-scoring game quickly (this isn't the first time this has happened, but that is for a different discussion). But (and we have been through this discussion before, back at the beginning of the season) when teams really start to think about how the game is played they should understand that although they CAN do something, this is a game where they don't WANT to do it.

Strategy is particularly important in this game. Standard tactics focused on driving your opponent into the ground will be used by the simpletons that haven't taken the time to really think through the game and how to maximize their scores. Veteran teams should hopefully know better, and help explain this to any of their alliance partners that don't "get it."

-dave

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Y = AX^2 + B.... ehhh, whatever

This is exactly why my team decided to go with a stacking strategy. Lowering scores does not help anyone, its a good way to win a lot of matches and still have a low standing. You want high stacks, because high stacks mean more points for everyone (expecially the winner); my team views stack destruction as a last option.

It seems to me that many teams are more focused on winning matches then the competition.

I personally doubt KOTH bots will be able to do what they set out to. Saying "We will knock the bins down into our zone, and stop robots from getting to their side of the field and we will do all this in autonomous mode" is a very ambitious claim. I still stick to my prediction that very few bots will be able outpush 2 other robots on the HDPE. The only teams I see doing this are suction-cup teams... and only if they use the suction cup to pull down adding more weight onto their wheels (and only then if the HDPE stays in good condition through the competition).

Dave: You guys made a great game. Its similar to last year in the rate at which the course of the match can change, but will appear much more dramatic. Tug of wars are great, but they are nowhere near as exciteing as teetering stacks. This will be a very dynamic game and a very fun one to watch.

As for this being the first time to wipe out a high score... your right - things could change just as quickly in 2002, but this year entire matches worth of work can be destroyed much more easily (I can't think of any robots last year that took balls out of the goals).

Good luck to everyone!
Greg

Well, see. . . I think that's just the thing; Winning matches is winning the Competition. If you can win matches by decimating every opponent you run into, qualifying points are totally irrelevant. Sure, you're bringing the curve down for everyone, but as long as you're on top, that doesn't make any difference.

Last season, I think, put teams into a very bad mindset. It has something to do with scoring, I would imagine. In 1999, scoring was accomplished by manipulating alliance-specific objects into position. In 2000, while there was a battle for the balls at the start, once they were in the goals, there wasn't much that could be done to remove them. It wasn't impossible, of course, as is evident by looking at the teams that wound up in the upper echelon of the National event, but that just shows the seed of what has become an important part of the 2002 and 2003 game.

In these games, all too often, brute strength is rewarded over ingenuity. The games are balanced too heavily toward giving points to having something in some specific position.

I believe that, in some regionals, stackers will manage to survive. If they can get a multiplier that does something beside give them victory. . . that is, if they can get a majority of bins and make a stack . . . that will greatly help their seeding. But, I don't expect it to happen often. When they're up against a king-of-the-hill robot that's faster to the punch and stronger, though, there's not much hope for a good stacker.

Of course, if I thought a king of the hill robot were the key to winning this game, my team would've built one. Clearly, we didn't. There are other elements of strategy and design that involve the bins that aren't being given due thought. It's those "under the radar" designs that are going to make things interesting and turn the tables of the competition.

Ingenuity in engineering in these competitions hasn't died yet. It's getting close, though.

when our team first started coming up with ideas we leaning towards a king of the hill bot, and we thought we had a really good idea because what we would use stuck to the sample piece of the platform that they gave us really really well. we ended up deciding on a stacker bot, it can do other things though. im glad we decided on this becuase before we shipped we got a chance to go drive on a field, out of curiosity i took a piece of the material we were gonna use and put it on the platform, slid like no other.

did the teams that decided to go for king of the hill test out their traction devices/suction-cups when the HDPE was DIRTY?

because the results for us were far different than when the HDPE was nice and clean, the platform will be clean for the first couple of matches but after a couple with robots running around on it and people stepping on it(dirty shoes) dirt will build up and some robots that thought they were sweet could now be almost usless

Defense of shutout strategy:
Nooone can argue that its best to have a high scoring round. How close would you want the match to be though. Lets start with a 25 point lead incase somthing happens on the ramp, either your not on it totally or the opposing team gets on. With 45 crates, counting which are where will be hard especailly because of the blindspot caused by the ramp and whoever is on top of it. So add in nother 10 point alloowance. So to be safe you should have at least a 35 point difference. The closer your target scores the bigger the risk your taking. If you win by 100 to nothing both times in the finals you win. In finals why take the chance of losing because you wanted close scores when you could shut them out twice and win?

Defense of the ramp-dom:
In my above scenarios its possible for the rampdom/stacker pair to allow/help the opposing alliance to move boxes into the scoring zone if they wanted to boost there score. The point is that if a rampdom hits the wall and secures the ramp he can control the tempo of the match, he can greatly effect how boxes/bots move from 1 side to another. With a stacker friend they have nearly absolute control of what the match will look like.

This is what I thought last year. Then at nationals I found I was unhappy with matches that resulted in < 100 pts. Thats what it took to stay on top, not winning: winning BIG. The layout of elims this year promotes this even more. If you set out to crush the opposition and they get "lucky" once, your done.

Your explanation would work if everyone set out with that mindset, but not everyone wants to crush the other team and win with minimal QP's.

Of course these are just my opinions and I'll probably be proven wrong, but until then I'm going to stick to them!

Greg

I hope that you are right, honestly. It'd be interesting to watch.

Unfortunately, I don't think there's as great a variety of robots and strategies as there needs to be to keep the game all too exciting. Rather than set out at the beginning thinking, "How can we beat teams that perch themselves atop the ramp?" it seems as if most teams thought, "We'll just be the team that perches atop the ramp."

It means that, really, if you didn't build the best ramp dominating robot at your regional, or in the country, you'll eventually be beaten. There's little else you can do. At least it seems as if some teams considered that, adding stackers or other modules to their designs.

Last season, some team's ditched their ball collectors almost immediately upon experiencing the game (254 comes to mind). I wonder how many teams may ditch their stackers this season. I know that already, we are planning to do that to some extent. But, we aren't designed to be a viable king of the hill robot, so it required some creative thinking as to what else we could do. ...and that's what I was hoping we'd see more of.... clever strategies beyong stacking or knocking over the wall or defending the top of the ramp. Y'know, just cool, efficient ways of screwing over everyone who thought they'd take the easy way out ;)

I wrote that poorly. What I meant to say, I think, is that any team that's relying on getting on top of the ramp first, and stackers in particular, aren't going to do well. If you can manage to get the bins to your scoring zone, you're in good shape. But, to me, it seems like everyone's putting all their eggs in one basket with their design and strategy. You either get to the bins first or you don't. There's very few teams that have shown anything that can reliably tip the balance of the game after that wall has come down.

I hope that the teams who have chosen to keep their robots hidden are doing so precisely because they have such designs. If our robot were designed to reliably control the score regardless of where the majority of bins land, I'd not have shown it. In fact, maybe we didn't ;).

I do believe teams can excel in more than one role, but not likely at the same time. Again, I just think that too many teams decide to let the matches be decided in the first 15 or 30 seconds - without really considering whether or not it needed to be.