Re: Ball Launchers? Ideas?
 

So what people really should be looking at is the shooting motion of basketball players and see if you design a mechanism imitating their motion.

Re: Ball Launchers? Ideas?
 

I hope teams, when designing, think of how humans throw a basketball. They don't launch it at the square of the backboard, they try to arc their shot.

Think of how your rotational velocity of your pitchers, pitch of the launcher, and distance from the hoop go into arcing the ball instead of launching it.

Re: Ball Launchers? Ideas?
 

This Thread has absolutely EXPLODED. Its great to see so many people thinking about this.

My two cents.

Speed. Both in terms of muzzle velocity and reload time.
A variable initial velocity is a great idea.
Very important.

Accuracy/Consistency. With wheels you run into the issue of spin (which
can be tweaked to even remove air resistance from the equation). Deformation is also a big problem because that compressed force will make the ball wobble when fired. (Although nominal, i need to look further into this)

Range. Simple enough. Must be consistent and long enough to provide for as many scoring opportunities.

Now. If you can set the launcher to 45 degrees and leave it there it makes the equation for finding the velocity to shoot an optimum parabola. And you can limit the number and size of moving parts with a fixed angle shooter.

(Hint Hint, Programmers this is way easier than solving an equation with both V and theta in it)

Thanks for reading!

Thomas 1939

Re: Ball Launchers? Ideas?
 

I think that using the human method is fine for humans, but since the robot isn't human, teams might need to play around with different methods and see what can be done successfully with the fewest degrees of freedom. In 2006, like I said, teams that used a single wheel shooter that gave the ball a lot of backspin were successful. Think about how it works, and what's required to do it.

edit: also look at the teams that were successful in 2009, although the number of balls was different, there were a lot of teams that scored consistently by getting right next to the target and dumping the balls in

Re: Ball Launchers? Ideas?
 

The target in 2006 was like throwing a dart at the wall. This year your aiming for a floating hole in the ground. What worked back then probably won't work as well now.

Re: Ball Launchers? Ideas?
 

I don't know about that, I got to hang out with the Falcons (team 842) yesterday, and we seemed to have more success getting the ball in using the backboard and backspin, than we did lobbing it.

But it's still pretty early in the season, hopefully we'll see some youtube action this week that will astound us all

Re: Ball Launchers? Ideas?
 

quick question: how are teams going to work with the weird height requirements?
the absolute height must not exceed 84 in
any appendage may not extend more than 14 in. beyond the frame perimeter

i can't seem to think how this works

Re: Ball Launchers? Ideas?
 

Horizontally, 14 inches, vertically, cannot exceed 84"

Re: Ball Launchers? Ideas?
 

OHHHHHHHHHHHHHHHHHHHHHH i feel so dumb now lol
man- i always over complicate things

Re: Ball Launchers? Ideas?
 

The biggest issue with the shooter fixed at 45 degrees would be if you are really close. The proximity would make it impossible to score in the top basket or even the middle depending on the size of your robot.

Re: Ball Launchers? Ideas?
 

At a glace, it appears this year's shot arc is going to be very different from 2006. I have been joking with my team that its going to be like kareem abdul jabbar's sky hook. The ball will have an early release (higher angle on the the ball's initial trajectory) and using the robot's frame perimeter and height to prevent the shot from being blocked.

I am really nervous about how large the backboard sweet spot will be.

Does anyone feel accuracy will be more important than frequency of shots made? My team was thinking that missing the shot and failing to rebound will give the opponents possession of another ball and a scoring advantage.

Re: Ball Launchers? Ideas?
 

Well if the balanced bridges can be worth 40 points in elimination rounds, I think they expect a decent number of shots to be made, so I wouldn't expect and amazing amount of ductility with making shots. But I have yet to test anything.

Re: Ball Launchers? Ideas?
 

I think arm styles are certainly worth of note and it looks like 1875 has one up and running: http://www.chiefdelphi.com/forums/sh...highlight=1875

1523 MARS had a "pitching style" arm in 2006 that (I believe) used a cam and spring set up. Their shots were extremely consistent but may not have had the ability to easily change trajectory.

Re: Ball Launchers? Ideas?
 

I guess I am thinking of where the point deferential will come from. I guess this will be steering a little off topic. If both alliances get the 40 points, then autonomous/hybrid and shooting baskets will decide the match.

I guess I am wondering how much of a disadvantage a missed shot would be. Suppose if team A that can only make 50 percent of the shots at the 3 point hoop and team B that can make 100 percent at the 2 point hoop. Then if 6 shots were made by both teams. Then the total would be Team A 9 points and Team B 12 points. Team B would also have opportunity to recover some of the missed shots of team A. This is an over-simplified example.