Re: How to get the ball over the overpass!?
 

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.

Re: How to get the ball over the overpass!?
 

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:D )

Re: How to get the ball over the overpass!?
 

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 :cool:

Re: How to get the ball over the overpass!?
 

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!)

Re: How to get the ball over the overpass!?
 

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

Re: How to get the ball over the overpass!?
 

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.

Re: How to get the ball over the overpass!?
 

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.

Re: How to get the ball over the overpass!?
 

Our team came up with the concept of a catapult device, niffty idea, it was quickly ruled out, but still the concept behind it was interesting....


the way we thought it out was alot of reliance on our teammates for hurding us the balls then we collect it up and launch it over...

it would have been quiet amusing watching balls hurdle threw the air haha...

some cons of it though were deffinitly in the aiming aspect and the distance of the ball...

Re: How to get the ball over the overpass!?
 

What was powering said catapult? When we were talking about it, we couldn't think of a safe enough, powerful enough device to do it? (A team member did the physics and put the ball traveling at upwards of 15 mph from ground level, 10 mph from 4 ft. to make it work)

Re: How to get the ball over the overpass!?
 

http://robotics.nasa.gov/events/2008_frcwebcasts.php

If you haven't found it buy now here it is....

:D enjoy

Re: How to get the ball over the overpass!?
 

I am not sure if teams are forgetting the size of the ball. Any gripper that is designed to grab a 40" ball will have to fold up inside of the 38"x28". I am sure you will see some arms that are capable of lifting the ball over the bar. This will require careful design due to the size and weight of this years ball.

Re: How to get the ball over the overpass!?
 

oh we didnt get that far enough in the catabolt concept... we diceded to toss that out rather quickly too... before we got that far... our team isnt even going to attempt putting the ball over the overpass.... but thats all Im going to say

Re: How to get the ball over the overpass!?
 

I'm not sure you understand the question (one that is being discussed in another thread I started). The question I have, at least, is whether putting the ball on the overpass, then knocking it off (forward, of course) counts as a hurdle.

Re: How to get the ball over the overpass!?
 

Im sorry ya I did read the question wrong

Re: How to get the ball over the overpass!?
 

There are ways to launch the ball with pneumatics. Using only a small cylinder our team was able to obtain 2ft. of VERTICAL travel.

The trick is to fill the cylinder halfway (using a latch to prevent it from opening fully). Then once the latch is removed the cylinder will extend incredibly quickly.

It should be noted that this method is potentially unsafe and would require 2 2" bore 1.5ft stroke cylinders to provide about 8ft of lift, but it is definitely possible.