Chief Delphi - ball cannon???

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Re: ball cannon???

Quote:

Originally Posted by gorillamonky (Post 805510)

not at all, there is absolutely no way for a human shooter to be accurate enough to design a bot around them. if you have done any testing at all you would have realized this, unless you have some crazy good shot on your team

And you believe that a robot will shoot better?

TBH, There will be robots that shoot well, and robots that shoot poorly ... and Humans that shoot well, and humans that shoot poorly. In the end, it'll be fun to watch :D

Re: ball cannon???

Quote:

Originally Posted by Daniel_LaFleur (Post 805530)

And you believe that a robot will shoot better? :D

no, i am reasonably sure that a robot will shoot even worse than a human, but i have no testing to prove this. my team is going with a dump type

Re: ball cannon???

We've been looking at both designs and seeing what we can get done on both sides of the equation. For the launcher we figured out how to get the camera to track colors and have a sketched out equation to calculate range based on trigonometry, however we've run into an issue on how to launch the balls. Our main design was to spin two wheels in opposite directions and accelerate the ball through them, but we can't get enough surface area between the ball and the wheels to really launch them. There is also the fact that it would be hard to get much capacity to hold balls on the robot. We figure 5 balls on the robot at one time is a stretch. The plus of a shooter would be the ability to better choose targets.

Our dumping design has just as many issues. As was mentioned earlier, really efficient dumping would mean essentially stopping both robots. Although we did find that a dumper is between 50 and 75% accurate within a foot, so if you could design a dumper that would release balls quickly you could probably do a drive by dump. The capacity on a dumper is 6 to 7 balls. Using a dumper, though, you wouldn't be as able to choose your target, and once you dropped your balls you would have to collect an entire new set.

I think the key factors are going to be time and manueverability. There are 2.5 weeks left. At some point one design may be faster to build than another and it may be more beneficial to have the extra couple days to program and fine tune than to do the other design. And, on a frictionless surface, you're going to want as much control over your bot as you can get.

Re: ball cannon???

This is our launcher prototype. It has a bit of a lexan "nose" that fits over it, and the aluminum version will have it completely one piece, pivots and raises.

http://www.youtube.com/watch?v=Dxqu9...eature=channel

Re: ball cannon???

Quote:

Originally Posted by DuzieInuKenshin (Post 805555)

We figure 5 balls on the robot at one time is a stretch.

The capacity on a dumper is 6 to 7 balls.

This depends on design.

Our shooter has the capacity to hold up to 11 balls as it is currently designed and I expect that some teams will be capable of holding even more than this.

Re: ball cannon???

Just as an update, we upped the speed of our cannon to 3700 rpm, and the diameter of our roller is now 5" with about 1.5" compression. Here's the vid:

http://www.youtube.com/watch?v=qNH4hb7crFU

it's very consistent, we'll be testing distance controllability with varying the motor speed tomorrow (just got electronics board mounted). Gets ~10 ft and probably still around 3-4 balls per second (also need to test spin-up time).

Re: ball cannon???

Our team has veered from using a shooter because we figure the balls will veer because of their holes. However, I have seen designs that seem to be quite accurate. Therefore I don't know.

Re: ball cannon???

Quote:

Originally Posted by JesseK (Post 792553)

Heck yea, we're doing a shooter too. I prototyped a successful launcher yesterday that went 8 feet, and the students are almost done prototyping a shooter today. Combine it with a turret and camera and you're golden -- they key is the type of shooter. Get creative, you don't have to use flywheel style...

We're not using a hopper though. Our overall game strategy dictates that we won't have the time to collect large amounts of moonrocks, so we'll fire what we get almost as soon as we get it. We'll have a max of 6 moonrocks in our bot at once, and probably then only at the start. This is for simplicity's sake though...

thats sweet!!