Puncher Shooter

[one4robots]

Has anyone attempted a pneumatic puncher for a shooter? Do you have plans for one?

[cadandcookies]

My team hasn't. When we did the math on how much air we'd have to carry in order to meet our "reload" requirements, it was too much for our liking.

[one4robots]

Originally Posted by cadandcookies

My team hasn't. When we did the math on how much air we'd have to carry in order to meet our "reload" requirements, it was too much for our liking.

Thanks cadandcookies - May I ask how many storage tanks you calculated? We were thinking 4 would be sufficient with the new (slower) compressor.

[cadandcookies]

Originally Posted by one4robots

Thanks cadandcookies - May I ask how many storage tanks you calculated? We were thinking 4 would be sufficient with the new (slower) compressor.

I'm not actually a part of the team that calculated this (that would be our manipulator team), I just asked why they weren't prototyping with pneumatics and that was the answer they gave. I'll check with them next time I'm in the shop.

[theCADguy]

Team 20 has attempted several prototypes of punchers, but at best we could only shoot a few feet. For us, The inspiration for the design came from 1114's 2008 robot, which we later found to actually rely on the release of potential energy, instead of pneumatics.

[Whippet]

Originally Posted by theCADguy

Team 20 has attempted several prototypes of punchers, but at best we could only shoot a few feet. For us, The inspiration for the design came from 1114's 2008 robot, which we later found to actually rely on the release of potential energy, instead of pneumatics.

Would it be possible for you to release some data from these tests? This might just be what we need to score in the bottom goal with.

[Trey178]

Team 178 has had luck with the pneumatic punter. We tested a prototype that gave us a 17" push, divided into 3 stages, with (at least) 50 psi. When tilted (angle currently unknown) it was able to clear the truss and the high goal. Plus, it had enough air stored for two more cycles. Video has been recorded of these tests and I will provide a link when available.

We've got more 8" pistons on the way so the above configuration is not final. If this does become part of our bot the students need to figure two things.

1. Where to mount the completed mechanism on the robot
2. How we can properly seat the ball in place for an optimal shot

EDIT 11:24pm: link to video highlighted above. Go to 10:50 in.

[one4robots]

Originally Posted by Trey178

Team 178 has had luck with the pneumatic punter. We tested a prototype that gave us a 17" push, divided into 3 stages, with (at least) 50 psi. When tilted (angle currently unknown) it was able to clear the truss and the high goal. Plus, it had enough air stored for two more cycles. Video has been recorded of these tests and I will provide a link when available.

We've got more 8" pistons on the way so the above configuration is not final. If this does become part of our bot the students need to figure two things.

1. Where to mount the completed mechanism on the robot
2. How we can properly seat the ball in place for an optimal shot

EDIT 11:24pm: link to video highlighted above. Go to 10:50 in.

Thanks Trevor! That's exactly what I was hoping to hear! One question. What is the diameter of the 8" cylinder you are using?

To answer one of your remaining problems, we have receiver arms that catch the ball and funnel it to a back wall. From that position it is supported in 3 spots and we will shoot it from there.

[Akash Shah]

We have actually tried prototyping a slingshot type of idea where a rod is pulled backed to the desired position and is let go to basically punch the ball. We have received satisfactory results launching the ball several feet (Didn't Measure). It is not that reliable though with the hazard of the surgical tubing maybe breaking in a match.

[A Dog IRL]

We at 5196 tried a puncher with a pneumatic cylinder that's both high velocity and short travel. Even at (over the allowed range) 120psi the puncher did not throw the ball far enough. We attached a weight to the end and it extended the travel distance by a foot.

[pfreivald]

Yesterday our winch-back punch threw the ball 38 feet, with the apex right in the sweet spot for the upper goal. Prototyping matters a lot--at first it looked like an utter failure, now it looks great. (Except that it's heavy, slow, etc, etc. Optimization still needs to be done.)

Note that we're prototyping four different launchers and designing our robot for modularity to accommodate whichever of them we ultimately decide is "best".

[one4robots]

Originally Posted by pfreivald

Yesterday our winch-back punch threw the ball 38 feet, with the apex right in the sweet spot for the upper goal. Prototyping matters a lot--at first it looked like an utter failure, now it looks great. (Except that it's heavy, slow, etc, etc. Optimization still needs to be done.)

Note that we're prototyping four different launchers and designing our robot for modularity to accommodate whichever of them we ultimately decide is "best".

Thanks Patrick! Can you describe (or share a picture) of "our winch-back punch?"

[pfreivald]

Originally Posted by one4robots

Thanks Patrick! Can you describe (or share a picture) of "our winch-back punch?"

It's a slider carriage with a punch on it, powered by a giant load of surgical tubing, currently pulled back and held (for prototyping purposes) with a screw drive. We're releasing the catch with a hammer at this time.

It's big. It's heavy. It's slower than we want our reload to be. But it achieved the "perfect shot", so we're not ruling it out yet!

I'll see if I can sneak into our supply closet and snap a picture in a few minutes.

[Trey178]

Originally Posted by one4robots

To answer one of your remaining problems, we have receiver arms that catch the ball and funnel it to a back wall. From that position it is supported in 3 spots and we will shoot it from there.

It seems our teams have ended up with a similar train of thought. At the end of week 2 we had a complete mock-up of one of two designs we felt were feasible. This uses a wide frame orientation with our puncher (mocked using a wooden ramp stopper from 2012 and a frisbee from 2013) with a 'wheels on top' intake/passing system.

It appears at 2:40 in

We've also refined the puncher design with support plates, which are further in the video.

[nickansh1]

Our first idea was to use a pneumatic puncher but it just didnt have power or speed to punch the ball very high or far. We have switched over to a spring-powered catapult with a winch system to wind it back up, it works fairly well.