Launching Shooter-style

[jbsmithtx]

I'm wondering if there are any teams who have attempted to launch these large objects shooter style, and what success they have had. Video would be wonderful, and any sort of prototype and results works too.

Our team is looking at designs, and it just seems like the pneumatic punchers are relatively ineffective, and the catapults seem INCREDIBLY easy to block. I have not found that anyone has addressed this, because if robots are in this fashion

{---[_•_]---------} <-Goalie zone with robot driving laterally

....... Π.......... <- Shooter facing towards the goal

Assuming standard tank drives (which >60% of teams do) the Goalie (despite having a small blocker, should have a seemingly easy block on this single robot.... Which we assume cannot strafe, and is stuck with turning or back and forth motion.

Is anyone understanding me here? This seems way too easy to block.

[Ether]

I'm wondering if there are any teams who have attempted to launch these large objects shooter style, and what success they have had. Video would be wonderful, and any sort of prototype and results works too.

Team Copioli, Build Blitz. Motorized kicker.

[jbsmithtx]

isn't that still nearly the same as a catapult though? Unless I'm missing something... It seems to be the same concept, yet with a different design.

I'm talking shooter style, like two spinning wheels on either side... Like rebound rumble shooters, or even last year's shooter's, though they were powered on one side to create a spin

[geomapguy]

This could have potential to rip the ball fabric

[Jay O'Donnell]

I simply don't see there being enough force to shoot these balls with shooter wheels based on the motors we have available (this could be totally wrong it's just a hunch). Also yes, there is a good chance of ripping the ball apart and that's bad news.

[redneckrobot]

we had tested the pneumatics idea and it will not ever work due to not having enough speed hitting the ball with a small bore size

[jbsmithtx]

Well the ball is only 2-3 pounds (2.75 on the AM website) so I don't think mass is a problem. And the drag might be large on such a large game piece, but the catapults seem to fly fine....

I understand the risk of tearing fabric, but surely with them inflated to the instructions provided, I would think this risk is relatively low... I'm just surprised that no one looks to have at least TRIED it....

We should have a working prototype in the coming days, so if no one has anything, I'll post our results in a few days

[Jim Wilks]

We should have a working prototype in the coming days, so if no one has anything, I'll post our results in a few days

Please do post your results.

[Ether]

the Goalie (despite having a small blocker, should have a seemingly easy block on this single robot.... Which we assume cannot strafe, and is stuck with turning or back and forth motion.

Read Team JVN's blog post about the "sweet spot" (flat trajectory). The shooter can rotate a lot faster than the goalie can translate.

[Ether]

we had tested the pneumatics idea and it will not ever work due to not having enough speed hitting the ball with a small bore size

So up the speed with a lever and put a big paddle on the end of the lever.

[Ether]

I simply don't see there being enough force to shoot these balls with shooter wheels based on the motors we have available

Then use a heavy flywheel to store the necessary energy.

[julianpowell]

Our team is looking at designs, and it just seems like the pneumatic punchers are relatively ineffective,

The problem with pneumatics is that the standard solenoids restrict the air flow so that any piston with enough energy to launch the ball moves way too slowly.

One way around this is to buy different solenoids, Mcmaster has some models that have a flow coefficient three times bigger than the stuff on Andymark.

Another solution is to just use multiple smaller pistons.

[jbsmithtx]

Read Team JVN's blog post about the "sweet spot" (flat trajectory). The shooter can rotate a lot faster than the goalie can translate.




So then this robot can still turn and maintain it's shot without having to move? I understand this, but is this 87 inches enough to vary your shot?

[cmrnpizzo14]

Team AndyMark originally prototyped a flywheel style shooter for this year. I don't think that they had any success and it was only mentioned in passing in the video but I'm sure if you shot someone on the team a PM or email they would be happy to share the results with you.

I think that someone on youtube tried a shooter like this too but I can't remember, I will look for the video and post it if I find it.

[Ether]

So then this robot can still turn and maintain it's shot without having to move? I understand this, but is this 87 inches enough to vary your shot?

For the JVN bot, what's the distance from the robot to the apex of the trajectory, and what's the length of the sweet spot? Armed with that knowledge and a bit of high school geometry, you can get an idea who's faster, the goalie or the shooter.

[Ether]

Team AndyMark originally prototyped a flywheel style shooter for this year. I don't think that they had any success ...

I think that someone on youtube tried a shooter like this too but I can't remember, I will look for the video and post it if I find it.

Does anyone know what the minimum required ball exit speed is for a serviceable shooter for this game? From that it should be easy to calculate a good guess for the necessary wheel moment of inertia.

[jbsmithtx]

For the JVN bot, what's the distance from the robot to the apex of the trajectory, and what's the length of the sweet spot? Armed with that knowledge and a bit of high school geometry, you can get an idea who's faster, the goalie or the shooter.




I presumed that the angle for the was small... I was incredibly wrong. With that setup, he has 60° of shooting, and the goalie has a distance of 20 feet to guard (assuming that they are a perfect spot. Even being in the general are gives them 10-15 feet along the goal in which they can shoot. This just seemed so small to me, but now this area is large and effective. Thank you

[steinra]

Does anyone know what the minimum required ball exit speed is for a serviceable shooter for this game? From that it should be easy to calculate a good guess for the necessary wheel moment of inertia.




I am not sure if it equates to a shooter, but to throw the distance we are looking at, up to 37 ft/s is the numbers we have crunched with about a 40degree launch angle.

Should be enough for those to figure out how far we are looking to get the ball to travel. :)

Randy

[Pretzel]

Does anyone know what the minimum required ball exit speed is for a serviceable shooter for this game? From that it should be easy to calculate a good guess for the necessary wheel moment of inertia.



Our team calculated that it should take an initial velocity of around 10 m/s or greater to make a goal from 13 feet away (close to four meters) using a 45* launch angle. These are the rounded numbers we set as goals four our launching mechanism to keep in mind while designing them.

[one_each]

Don't forget to adjust for launch height.