Catching a ball
 

Our team was brainstorming some ideas today, and one idea was to make a catching mechanism that would take up quite some space on our robot. Would catching be worth getting the extra 10 points? We did some calculations and it came out as having less cycles and spending more time trying to catch the ball. It can be a good resource to have among an alliance, but it would be hard to have it on the robot with other mechanisms that would be on the robot.

Re: Catching a ball
 

If you can flawlessly integrate it into your robot and what you do, it's quite an asset to say "gimme the ball, coach". From what you're saying, it doesn't appear like you believe your catching system is very easily integrated.

As I said, if it's not really part of your system, unless it's so simple and small, let it go.

Re: Catching a ball
 

So, is anyone catching (or throwing really)?? Just wondering what the thoughts are since we all are playing nice together this year.... Not that we're not nice to each other other years...it's just....well you know what I mean.

Re: Catching a ball
 

Alright. Did anyone think of trying to catch a ball with the same arm mechanism to pick up the balls from the ground? It would be more difficult, but could be possible to catch it in the air.

Re: Catching a ball
 

Yes. And that's kind of what Zuelu562 is talking about. I see no reason why you could not make an all-in-one pick-up/catching/throwing mechanism. It all comes down to how you want to play the game and your team's abilities.

Re: Catching a ball
 

I came up with a design that can pick up balls from the ground, shoot (possibly full-court), pass and catch. However, it would be a hassle to get it within the dimensions because it involves completely enclosing the ball!

Check out the design here.

I haven't drawn the catching feature on it. However, just cut out a door at the top of the cage, move the conveyor belts to the side and build a hopper on top of the opening! Also, it is linear so it will also look kinda cool!

By the way, are we allowed to extend pass the chassey of the robot by, I believe 20 inches on each side, or is it just one side? If so, this is a perfectly feasible idea!!!

Re: Catching a ball
 

I have dreamt up a similar idea, except the full court shooting won't help you in this game per part B. And I'm 99% sure you get the 20" outside of your frame perimeter in all directions.

"A BALL is considered SCORED in an ALLIANCE’S GOAL if

A.a ROBOT causes one (1) of their ALLIANCE’S BALLS to cross completely through the opening(s) of one (1) of their ALLIANCE’S GOALS without intervening human contact,
B. the ALLIANCE ROBOT last in contact with the BALL was entirely between the TRUSS and their ALLIANCE’S HIGH GOALS, and
C. the BALL is not in contact with any ROBOT from that ALLIANCE."

You can extend 20 in in every direction but must be inside frame perimeter when match starts

Re: Catching a ball
 

Our team's game analysis method comes from Den Black, described here (part 1, part 2)

Before you ever even start talking about "how" you are going to build your robot, you should be doing a similar type of analysis to decide "what" you want to do and "why" you want to do it.

This year we have prioritized catching a ball quite high on our list of robot functionality. (I can't remember off the top of my head, but it might even be higher than high goal shooting.) One of the things we did in our analysis was figure out how quickly we could perform a teleop cycle if we had no help from alliance partners. The ability to catch a ball gives us either 1 or 2 additional cycles per match.

Re: Catching a ball
 

I don't think you catch because of the extra 10 points. I think you catch because then no one has to chase down a bouncing ball that had a decent amount of energy imparted in it. Personally, unless you have enough resources to make an excellent thrower, I think its a really really good idea to concentrate on catching, even if it means you can't throw. You may not do so well in quals but I think you will see the value in elims, as it is a really quick assist.

Just make your robot a huge 5 foot tall target with 20 inch extensions, the whole thing padded to deaden the ball and some way to release it to the ground. If all else fails, you turn around and play the kind of defense where you're a 5 foot tall box that it is unlikely anyone can shoot over. This is just my personal opinion, and my team does not agree, and we will not be building this.

Re: Catching a ball
 

We considered this, and concluded that it makes more sense to have a catching mechanism on the rear of the robot and a top-roller floor pickup on the front, or somesuch.

The floor pickup is useful for retrieving balls, and can reverse its drive to be a floor spitter, to either do floor passes to other bots, or to put the ball in the low goal.

The catcher wants to be able to get balls from either human players or other bots. We will first try to make a human-tossed ball catcher, and see if it can be made big enough to accept balls from other bots. Bounce deadening is quite the thing.

Another idea, more crazy of course, is to make the ball catcher like a Venus flytrap, with wide-open hoops on the sides that close in on the ball as soon as a pressure sensor plate detects that a ball inside it.

Re: Catching a ball
 

If I understand you correctly, if you catch but have no way of ejecting the ball, you will screw the team because there is only one ball available at any time (of your color)

Re: Catching a ball
 

yes 100 percent to be honest I think catching will be the dark horse of this game if you can do it well and consistently it would be an absolute asset when coming to elimination. but you would also need to be able to score or throw to do well in qualifications when your partners are random. I myself have a few ideas im finalizing that are simple and doesn't take up much space. But you always have the option to have a separate catcher attachment that you can quickly attack onto the robot prior to a match depending on your partners that round I have a filling some teams will being doing this

Re: Catching a ball
 

Well catching will be pretty difficult, considering that the ball is bouncy, and there is a chance that the mechanism may not successfully catch the ball every single time. In my opinion, it would seem to add time to each cycle if you tried to catch as well, since you now have to concentrate on catching a ball, and extra time to pick it up if it didn't catch properly. If you have a mechanism that will catch every single time successfully, then I can see how it can be faster.

Re: Catching a ball
 

have a catcher that doesn't catch the ball every single time wouldnt be any slower though because you would still be chasing a bouncy ball around the field but when you do catch you would safe time catching is important

Re: Catching a ball
 

You have some sort of gate at the bottom of your robot that opens up, releasing the ball to the ground near a robot was my original thought on that. Sorry that it wasn't clear.

The issues I see is how easy it would be to get an opponent's ball, and the loss of auton points.

Re: Catching a ball
 

Being able to catch adds 20 points. These points are added instantly, without waiting for the ball to be scored and could be used as an "end of game" move. Thus, a robot that can catch and release into the 1 point goal over multiple cycles seems to be worth more than a robot that can pick up a ball and shoot at the high goal. Of course, without an alliance partner capable of throwing...
Based on my interpretation of the rules, a catching robot is allowed to have a catching device that expands to cover about 30 square feet.

Re: Catching a ball
 

Well yes, but you would spend that extra 1-5 seconds trying to catch the ball, which can make quite a difference in some cases. And of course you still have to get the bouncing ball, but you could also cycle by rolling the ball under the truss, if it happens to be better than going over the truss.

Re: Catching a ball
 

I don't understand where you came up that catch points both add +20 and are added instantly...
Per the game manual,
Emphasis mine.

Re: Catching a ball
 

We had an idea of extending aluminum rod backed lexan out 20 inches on each side of us with a slight lip. We are trying to find a way to get it to pull inwards, but have not yet. We think it should count for a catch if the ball lands in this permitter and stays on the platform, we retract it, the ball falls to the ground and we pick it up from there.

One idea for extending was to have an aluminum zig zag thing (like the bottom of an ironing board, repeated, like on a construction lift) that would extend a canvas. This may not count as catching thought, but it could work. :confused:

Re: Catching a ball
 

catch 10+ truss 10 = 20 points. This thread explains it to the best of our knowledge. It still is rather unclear until the QA answers the question.

http://www.chiefdelphi.com/forums/sh...hreadid=124126

Re: Catching a ball
 

Yesterday I thought catching would happen by gently tapping a ball over the truss. Today watching an interesting game of racket-ball I realized the true potential of catching.

Robot 1 gets ball from human player and immediately shoots it over truss at far wall. Robot 2 is approximately between 2 and 3 feet in front of the wall and catches the rebound. My prototype of a 68 inch box seemed to be able to catch a good deal of balls from 35 feet... Then 1 or 10 point goal shoot as you see fit.

Always keeping your shooting / acquiring mechanism facing the goal is a huge advantage! Also even when the ball is not caught it should be close to you.

Re: Catching a ball
 

I 100% agree. The bouncing ball problem was one reason that we almost ruled out high-court shooting or shooting over the truss; chasing down that ball could be a big problem. If you use a simple pusher to herd the ball into the low goal, it's not much of a problem. But if there is a high court shooter who needs to chase down the ball, a catcher could be a big part of the game.

Re: Catching a ball
 

My design actually consists of both, allowing the balls to be picked up, caught and shot! Also, run the conveyor backwards and it will do a pass at a low speed that won't damage the other robot.

Re: Catching a ball
 

"Throwing" (over the truss) can be accomplished using a shooter designed to shoot at the high goal. The truss is about a foot lower than the high goal, so any shooter made for the high goal will also be able to clear the truss.

Catching seems difficult, but what we have figured out recently is that everyone is making catching a lot harder than it has to be. The manual defines catching as "when a BALL SCORED over the TRUSS by a ROBOT’S ALLIANCE partner is POSSESSED by that ROBOT before contacting the carpet or HUMAN PLAYER" and possession as "A.“carrying", B. “herding”, C. “launching, and D. “trapping"". Thus, a catching mechanism is not entirely required unless a team has the time, space, and resources. If a robot simply places itself in the right place such that the ball will bounce off and head in the right direction at the right angle, it should theoretically count as a catch.

That said, my condolences to the poor referees who have to decide what counts as a catch, what counts as possession, and what counts as an assist.

Re: Catching a ball
 

Yeah, I've been thinking about this too, and there's nothing preventing the first robot from being a goalie. I wouldn't be surprised to see an alliance turn it into something similar to volleyball at some point.

Human Player throws it up goalie serves it, second robot either takes the shot or serves it up for a third assist.

If an alliance was able to do this, the importance of a goalie would be critical.

Even just a static punter would be quite valuable.

Re: Catching a ball
 

Er, check the blue box under that definition:

(Emphasis mine)

Therefore, a ball bouncing off a robot placed in the right place seems to be just "deflecting," which is NOT possessing and therefore NOT a catch.