How to get the ball over the overpass!?

[llama]

our team is having issues with this decision as well... we have a general consensus though that we do not want to use an arm but rather a claw/fork lift hybrid because of the balls immense weight and size

the problem with using an arm also is the cantilever effect that is generated by extending the arm so far away from the bot (at best you'd have the arm one foot horizontally and 6ft vertically from the base of your bot and that adds up to be some intense weight pulling you into the bars)

[RyanCesiel]

The animation gave has a lot of ideas (many can be a joke), including things like a forklift and an arm - check that out if you haven't already.

[Travis Hoffman]

Originally Posted by llama

the problem with using an arm also is the cantilever effect that is generated by extending the arm so far away from the bot (at best you'd have the arm one foot horizontally and 6ft vertically from the base of your bot and that adds up to be some intense weight pulling you into the bars)

This was marginally successful during testing...

http://www.delphielite.com/~team48/Media/IMG_2067_2.jpg

The base of the ball is about 5.5' off the ground in this photo. We ran several full speed trial runs at this height - the robot was stable upon sudden stopping about half the time. Under more manageable forward speeds - those at which you'd be moving to position your arm to cap/hurdle the trackball - it behaved well.

This arm's tilt feature lets you reposition the ball over the bot's pivot point quite nicely for transport. The extension stage was designed to lift the entire weight of the robot off the ground, and therefore, it easily and quickly handled the lifting of the ball. Even the lil' ol Globe motor-driven hook stage had enough oomph to elevate the ball further....at a snail's pace.

This little test gave us a decent idea of what will be needed to manipulate this 40" beast.

[robogeek753]

I don't know how a previous poster got a pneumatic to launch a ball, but generally speaking any kind of projectile with a huge ball like that is going to be hard to do. I can almost gurantee that a pneumatic in any configuration won't work (to make the ball act like a projectile). Gas shocks may well be too slow. The only options I see are inertia (as mentioned) or a really big Aim High style cannon (good luck with that though )

[=Martin=Taylor=]

Originally Posted by robogeek753

I don't know how a previous poster got a pneumatic to launch a ball, but generally speaking any kind of projectile with a huge ball like that is going to be hard to do. I can almost gurantee that a pneumatic in any configuration won't work (to make the ball act like a projectile). Gas shocks may well be too slow. The only options I see are inertia (as mentioned) or a really big Aim High style cannon (good luck with that though )

Perhaps I should qualify my previous statement by saying that the ball was launched off of our ramp and landed 4' away. Such a design could be used to hoist the ball up the desired height and then shoot it over the overpass. But shooting from the ground... Well... With pneumatics I'm gonna say thats imposible

[robogeek753]

Still pretty impressive (must of been one heck of a piston and/or ramp) but it makes more sense now.

See you at the Oregon Regional (can't wait to see that giant ramp w/ piston launcher!)

[DonRotolo]

Originally Posted by Hachiban VIII

With pneumatics I'm gonna say thats imposible

Nothing is impossible...but I sure would hate to be the guy who had to make that work...

[BigWhiteYeti]

I think the best way to make use of a piston would be in combination with a forklift, using the lift to raise the ball to five or six feet, then jabbing at it with pneumatics to push it over. I think this would be the most efficient way to hurdle the trackballs. Unfortunately (in my opinion) our team is bent on trying to create an arm with a three-point pneumatic grabber. If anyone manages to create an efficient grabber that won't tip the robot when it tries to hurdle the ball, I'd like to see it.

[robogeek753]

Our idea (suprisingly enough, we haven't had enough time to build it) is to build two concave claws that support the ball (much like the overpass), lift it up to 6'3" and then use two small but long pistons to roll it over or into the overpass (if into then we just move forward a pit and push it out). Due to the small force the pistons are exerting, the robot won't tip.

[silicon_ghoti]

Originally Posted by Hachiban VIII

Perhaps I should qualify my previous statement by saying that the ball was launched off of our ramp and landed 4' away. Such a design could be used to hoist the ball up the desired height and then shoot it over the overpass. But shooting from the ground... Well... With pneumatics I'm gonna say thats imposible

Hmmm... I was thinking the same until Monday afternoon. Now as I throw this out there I get the feeling that I may recieve some flak about not reading the manual, but I would like to ask, "Is this legal?"

What we did was take a 2" bore, 2' (about ish) stroke cylinder and cover up the air port nearest the piston, then we pressurized the other side to 60 psi. The piston extended out about 16" and stopped. We then removed the cover (thumb) from piston side port and the piston shot out with a resounding CLANG!!!! (In otherwords a GREAT deal of force.)

But the reason why our mentors questioned the legality is the little FIRST rule that states that, you cannot compress air in "non-Clippard" containers. I have asked an alum, and have yet to hear back. Now I'm curious as to what the FIRST community has to say.