Goalie Bots
 

After watching some of the competitions from over the weekend I'm much less skeptical of the goalie strategy and I actually think that this could be fairly viable now. Just from watching Southfield and 4854 (I think, my apologies if the number is wrong) a goalie caused serious havoc.

https://www.youtube.com/watch?v=7GxroA_wcIo (Southfield QF1-1)

Are there any teams out there that are dedicated goalies or are considering to have a goalie strategy in their back pocket? Particularly any auton goalies that are willing to share their secrets.

Re: Goalie Bots
 

From what I saw the bot never actually blocked in the goalie zone as in extending in it, but it did play good defense, but then again any robot can, here is Team Texplosion, they were in the Alamo Finals http://www.youtube.com/watch?v=HkqRNhau6Ik I really want to see a goalie bot block some high goal shots, it seems like this robot knows when to and when not to goalie the high goal. Good goalie will be smart enough to only block when needed and play good defense when not!

Re: Goalie Bots
 

Phenomenal play at Alamo, you guys were very good. I will look for the matches in which 4854 actually plays as a goalie, they had a few blocks I think. They also used their height to block outside of the goalie zone at times.

Re: Goalie Bots
 

I agree, but I'm not on their team, I just like their driving style a lot.

Re: Goalie Bots
 

At the end of the video there are two people dashing out on the field do anyone know why?

Re: Goalie Bots
 

There were dead bot issues during those quarter-final matches. So what your seeing is the FTA...

Re: Goalie Bots
 

Those are the FTA's trying to find out why 33's robot died at the end. When you have a reputation like the Killer Bee's your robot typically doesn't just stop moving. I'm guessing they were anticipating something catastrophic and then were happily relieved to see no smoke. We had the same response from FTA's last year after a 90" tumble at West Michigan.

Re: Goalie Bots
 

Over here at 1710 we have a pretty complicated strategy. Our bot is committed defense and our auton is pretty different from the normal strategy. You're welcome to PM me if you have more questions.

Re: Goalie Bots
 

We have both a shooter and goalie pole. Check out our facebook page, twitter (@team2410), or my Chief Delphi avatar/media to see it.

Re: Goalie Bots
 

Goalies can't block the 1 point goal or the ten point area in front of said goal. Teams just haven't adapted yet.

Re: Goalie Bots
 

Why can't they block the one point goal?

Re: Goalie Bots
 

You can block the one point goal. But the extra height allowed in the goalie zone is not useful for that. So at that point you are no longer a "goalie" bot, but a robot playing defense. They also can't use their extra height to block the high goal behind the low goal.

Re: Goalie Bots
 

I just saw your robot (it's pretty great!) Do you think we have the time to make a quick high goal blocker (similar to yours) until March 20? Thanks!

Re: Goalie Bots
 

But they can use a 20" extension to block the one point goal and a vertical 6" cylinder to block the high goal at the same time. Making them still a goalie, but one that can multitask.

Re: Goalie Bots
 

You can't block all three sides of the 1 point goal at the same time... Easily.

If you are blocking the front and top, not only is the side open, you also probably are out of the goalie zone and you're leaving the ten point wide open. If you block the side and top, you leave the front open as well as the section of the goal above the 1 point goal open.

Re: Goalie Bots
 

I'm personally surprised to not see these goalies have tails and utilize the 20" extension. One of the worst things about a penalty shot in soccer is you have to stay on the line. In our case as long as your in contact with your carpet you could move much further into the playing field, thus cutting down the angles on the shot. If designed right, your blocker could be as far as 3 ft from the goalie line.

I don't follow. Couldn't you just have a cover (like 3 sides of a cube), that you put over the goal. If the cover was 20" x 20" x 20", I don't think anyone would be scoring on that lower goal.

Re: Goalie Bots
 

Unless a robot was purpose built for this specific task, I do not expect this functionality to be seen at all this year. Not really a "just have a" mechanism. This does not change that it is impossible for a robot to block the 10 point goal above the 1 point goal.

Re: Goalie Bots
 

That's also a near impossible shot to make if a goalie is blocking as far as they can over. That shot would have to be shot probably within an inch or two (someone else can do the math if they want) to make it without hitting the goalie or the side of the goal. Setting up that shot will take time, which achieves the goalie's point, to take up your time so that you can't do as many cycles.

Goalie Bots
 

I think it would be possible to make one in that time with a little bit of hard work, it's a pretty simple set up with a little problem solving to make sure it's legal and stable. If you do get it done, please share, I'd love to see how it turns out. Eli2410 knows more about it though so he's the one to ask.

Re: Goalie Bots
 

I'd say it depends a lot on how precise you can machine parts, how much time to work you have, how much weight you have to spare, and how quickly you can get supplies. If one of these four factors is on the bad end, I don't see it happening. If all of these factors are in your favor, you may be able to do this.

Re: Goalie Bots
 

As one of the group that decided to pick 4854 for our alliance, we where hoping to get a block during Auto, but no luck. Although they did get close. More time and thoughts we might have been able to get blocks during autonomous. Time to better calibrate I think we could have had them blocking shots. If we could it could have really swung the matches.

Most of the time they had good driving to shut down 33. We had watched them in multiple matches drive very well and shut down a team and even alliance. With one ball out there, if a driver plays well it can really slow down an alliance. Its unfortunate for us in those matches that both us and alliance partners died a few times. I think a lot of people where surprised by the pick (Ranked 37 of 40) but after watching realized why we made the pick.

Re: Goalie Bots
 

Can't the 6" cylindrical projection upwards be on the 20" horizontal projection, thus covering the area above the 1 pt goal?

Re: Goalie Bots
 

I don't see why not, but that would be a complex mechanism to make, and as far as I know no one has.

Re: Goalie Bots
 

Almost impossible, what are you taking about? Unless the goalie is extending outward 20 inches AND the extension is nearly 60 inches tall this shot isn't being blocked. And at this point, we are talking about a hypothetical robot with multiple complex purpose built appendages. This robot doesn't exist. Not that it couldn't, I guess, but it's a huge investment, not trivial.

An extension above 60 inches cannot be there as I believe the 1 point goal is not the goalie zone. Clever, but nope.

Re: Goalie Bots
 

If the "there" in that sentence is refereing to over the one point goal than I don't see how the rules prohibit that.

As long as a robot is touching the carpet in the goalie zone their 6" diameter blocker can be anywhere they can legally reach.

Re: Goalie Bots
 

Not without getting a 50 point penalty for possessing their opponents ball per Q&A 170

Q170

Q. Regarding possession of opposing alliance's ball: If a robot is attempting to score a 1-pt goal, if an appendage of a defending robot either a) holds the ball from dropping into the top of the goal or b) causes the ball to be "pinned" as it's pushed in the front goal, would it be illegal possession?

A. Yes.

Re: Goalie Bots
 

That's what I got from it too. The more interesting challenge is designing a mechanism that can a) extend 20 inches past the frame perimeter, and b) withstand repeated impacts of the ball at the very extreme of 20 inches out and probably at least 40 inches up.

When we were considering a pure goalie, we wanted to exploit the fact that the rules actually don't impose any height restriction at the beginning of the match, so if you start in the goalie zone, the blocking post doesn't even need to be retractable, which means the vertical blocker can be pretty strong. We also designed a two-way horizontal linear elevator based on 118's 2011 robot, which would have easily been able to take the impact of a ball. However, the weakness we encountered was that the goalpost acted like a wrench, with a huge mechanical advantage.



We stopped working on it around then because the mentors wanted to build a very different robot, but by then we had figured out that a blocker that could extend over the low goal is a major feature, and would mostly dictate the rest of the design.

tl;dr In my opinion, extending over the low goal to block the ends of the high goal is a difficult feature to implement unless the entire robot is built around it [and even then, it wouldn't be easy].

EDIT: Ooops, I forgot to mention: team 1710 executed this beautifully, and because the axis of the hinge is perpendicular to the torque above, they can easily withstand the impact of a shot. Bravo to team 1710!

Re: Goalie Bots
 

Re: Goalie Bots
 

I want to believe.

http://www.chiefdelphi.com/media/photos/39587

Re: Goalie Bots
 

You could still cover the "front" and "side" entrances to the low goal, and I think that very few robots are well equipped to shoot the ball into the top of the low goal.

Re: Goalie Bots
 

Very impressive. I was attempting to refer to the idea of a robot blocking the entire low goal as well as the area above the low goal, as was being compiled by the people responding to my posts. That robot is still impressive nonetheless. My greater point is that if you're a scoring robot driving toward the 1 point goal in the corner, in pretty much any realistic scenario there's at least one way to end the cycle, be it a side of the 1 point goal or the ten point above it.

Re: Goalie Bots
 

The lower bars are on window motors which can put them in front of the one point goal and we can move the blocker on top of the goal. :yikes:

Re: Goalie Bots
 

So in the theoretical world, you could design your low goal shot blocker so it deflected the ball without moving. A single deflection is not a possession. The other low goal is still open though.

Your driver will have to be very good about retracting to 60 inches before leaving the goalie zone or incur penalties.

Re: Goalie Bots
 

It's ok if you don't "hold" or "pin" the ball. A deflection is not possession, no matter where it happens on the field.

Re: Goalie Bots
 

I'm not talking about a deflection. I'm talking about an appendage that covers the front of the low goal. The way I read it is that if you have an appendage of yours in front of the low goal which causes the ball to be "pinned" as it's pushed in the front of the goal, it would be illegal possession. Isn't that basically word for word the Q&A?

Re: Goalie Bots
 

So as long as you don't hold or pin the ball, you're ok, right?

Re: Goalie Bots
 

Correct, as long as they don't try to push it in the low goal, you are good. The problem is the vast majority of low goal scorers I saw in week 1 competitions pushed the ball, not shot it, into the low goal. That means they are pinning it against your bot. As the Q and A says if they cause it to be pinned to your appendage you get a 50pt penalty.

Re: Goalie Bots
 

All the 1 point scorer has to do is try to score in the top of the goal. If the ball is prevented from entering, the other robot is holding it.

Re: Goalie Bots
 

Not necessarily. Let's say that the goalie bot has a wedge shape covering the top of the goal (ignoring any other rules that may break). If the scorer released the ball, it would roll away; therefore, I don't think you could say the goalie is possessing the ball.

Re: Goalie Bots
 

I was worried about that earlier in the season. I asked the Q&A about it, and they seem to have said that it would not be considered pinning if a robot was pinning its own ball against an opponent. I think Q170 was referring to more intentional, "actively push the ball into the guardrail"-type blocking.

Re: Goalie Bots
 

Not always true. There are some robots that move their goalie stick from side to side with extensions coming off the side of their robot, allowing them to move over the low goal. See 1710 above.

Re: Goalie Bots
 

Exception that proves the rule? ;)

Re: Goalie Bots
 

The thread is: http://www.chiefdelphi.com/forums/sh...84#post1382784