How to get the ball over the overpass!?
 

Any ideas guys???

-Pneumatics
-some sort of piston
-springs
-forklift


we were considering the springs but will FIRST allow?
is it safe? Cocking 3 springs before the match??

Pneumatics; how much force required??

Actuators; what kinds are allowed??
http://www.firgelliauto.com/default.php?cPath=94

what are your inputs??

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

First, those linked actuators are definitely NOT allowed. The only legal types are described in Section 8.

Springs--definitely watch the safety. If those things are deemed unsafe, you won't be able to do anything with them.

Pneumatics--I'm not sure about the force you'd need.

As for your ideas, how about having your team discuss those? One of them might stand out to your teammates.

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

Here's how I would do it. I would build an arm to grab the ball, and instead of throwing the ball, I would get the robot to extend the arm over the overpass to the other side. Then "drop" the the ball onto the other side.

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

rather than extending over it, just punch it with a piston once its high enough. Or build a catapult (some team will try it I promise you).

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

i think lots of teams are going to try this.

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

springs or momentum type *throwers* probably will have trouble getting past inspection because so much energy will be required, and it becomes very unsafe. Last year springs were used on our robot as a buoyant force so we could easily raise and lower our ramps, not in a way to rapidly release all that potential energy.

also is...

<R60> Items specifically PROHIBITED from use on the ROBOT include:
 Electric motors and/or servos different from, or in addition to, those in the Kit Of Parts, with
the exception of those specifically permitted by Rule <R59>.
 Electric solenoid actuators (note: electric solenoid actuators are NOT the same as pneumatic
solenoid valves – the latter are permitted, the former are not).

...why those firgelliautos actuators are definitely NOT allowed?

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

How about motorized conveyor belting arms (green polycord makes a return) that hug the ball and can either suck it in or spit it out?

Or the Technokat's Klaw from 2004? That thing was big enough grabbing a 30" ball. Imagine one that could encompass a trackball. Oy.

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

We are trying to find out if we can forklift it onto the overpass then push it off and over.

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

<R60> (which you quoted) prohibits motors that aren't in the Kit of Parts.

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

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)

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

They looked like pneumatics to me. Even then, there is a rule...

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

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.

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

Have you found out yet? (We're trying to find out the same thing)

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

Here are some tests my team did:

Pneumatics: Our team got the biggest piston we had laying around (1" bore 1.5' throw) and rigged it up to a pressure device rated at 60 psi (the maximum allowable pressure on the robot) and placed this piston behind the ball which we laid on some inclined sliders. Not only was the mechanism HUGE but it only was able to launch the ball 4' max, thus not clearing the overpass.

Springs: We used the same inclined sliders and made a little "cart" that carried the ball. This cart was attached to a mass of surgical tubing. We hoisted back the cart and released it. We were able to shoot the ball about 3'. This system was very dangerous, and involved the cart shooting forward and coming to a dead stop. We decided that designing a mechanism to draw back the springs would be very difficult.

And of course, neither of these designs presented a method of actually picking up the ball and loading it...

Forklift? :cool: ;)

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

Well here's what I wanted to do but couldn't because the gigantic flag holder is in the way, although I'd love to see someone try it. Basically, if you could hold the ball at the end of a pole (about 4' long maybe) behind your bot, as you travel towards the bars (finish line), plant the front end of the pole in the carpet with a grippy foot on it, and you pole vault the ball using the bots inertia.
The bot itself is your best source of stored energy which can be transfered into the ball.

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.

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

If it is potentially unsafe, I don't think that the robot would pass inspection. In addition, depending on where said latch is, it would probably constitute an illegal modification to the pneumatics circuit and/or components. Without explicit permission from FIRST, I wouldn't reccomend that approach on any robot.

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

Personally, the forklift seems like the best idea to me

Pneumatics, Springs
Pros: Faster, and they may fit in the minimum size dimensions (no need to unfold)
Cons: You'll need a LOT of energy to launch a 10 pound ball 6 feet in the air. The springs to do this would have to be huge, and I doubt FIRST would allow it. Also, how would you reload the springs for more than one hurdle?


Catapult
Pros: I can't really think of any...
Cons: It would have to be huge to get enough leverage to launch a ball, so it would involve some serious unfolding to get out of the minimum size box. Also, when you do have it unfolded, moving would be problematic.

Forklift
Pros: There aren't very serious cons xD
Cons If it becomes top-heavy, your robot could tip. Pay attention to balance.

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

It's not as bad as Matt suggests....there is some cushioning as the cylinder reaches full travel (it has to compress some air on the top side of the piston as it reaches full extension, because of how the valves work). And the catapult mechanism could be safely enclosed in the robot, with adequate protection around it.

No modification of the cylinder is necessary, since the latch is on the lever that the cylinder actuates.

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

Oh, you just need to spend more time thinking about it :)

The catapult itself need not be very large, as long as there is some structure on the robot that will hold the ball in position, such as rails or bars that it can rest on. The catapult only needs to be a couple feet long.

We have been using energy calculations to study the feasibility of various catapult designs, I think they figured it would take about 80 or so Joules to launch the ball over the overpass.

Next design we're working on involves a motor, with a flywheel type gizmo with a connecting rod that actuates the catapult. It would be a relatively low speed device that would not need to make more than one revolution per launch, I think.

Fun stuff....we're discussing a few of these ideas on our N.E.R.D.S. forum too.

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

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.

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

If you got this to work, you would probably win every design award your regional offers. lol

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

an idea that was thought up by my team was to use a holder underneath the track ball, make the holder go up or down in angle, then have like a pneumatic bulldozer bar shoot out and almost kick it over or shoot if you prefer.

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

We're planning on using telekinesis.

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

Hmm, can you prove that's a legal power source? As long as you don't use gerbils, I suppose it passes the flowchart.

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

Trebuchet? ;)

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

1885 is considering using the power of steam, so we're looking into building a great big pot with boiling water beneath a "cannon". It will be complete with a pressurization chamber and several parallel tubes since the durn things are so tiny. We'll also have some 2" Bose speakers on the right side of our robot pointing to the crowd that will play a nice BOOM whenever the ball is shot. Vintage late 1800's :D

No, I'm not serious

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

Well you think with over 16 years in the business some form of mutation would show up. That or it's a particularly potent form of geekiness.

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

How about dribbling the ball from below. As you drive around you start bouncing the ball straight up in the air. You only have to add a small amound of energy with each bounce thus everything would be quite safe. With each bounce it gets higher and higher and as you pass under the overpass you stop the robot and the ball keeps going. Then you run under the ball and catch it for the next lap. I think a robot that can dribble would definitely earn your team some kind of technical award.

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

Sounds like you'd be a perfect alliance partner for us! We'll install our own speakers and play miketwalker yelling out "Oink, oink!" just before you fire!

I can smell the Einstein gold already...

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

our team is considering the forklift + electric actuator design.

We would forklift the ball atleast 3' above the ground and use the actuator to hurdel the ball over the overpass... of course balance is crucial in this case, but if we tilt fork lift so it would form a right triangle from the back of the robot of the front, all the weight will be on the center of the bot rather than the front...

what do you think??

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

Can you use springs on your robot, or is it against rules?

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

Unless the operation violates <S01> or is deemed unsafe, you can use them. Just expect a little extra attention from inspectors making sure it's safe.

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

our new design is that of a forklift type deal. except in the shape of a ring so that the trackball sits in it comfortably. then above the trackball there will be a third arm which will keep the trackball from falling off of the ring/ and then that third arm will also be able to swing in a 360 degree circle so it can be used to "kick" the trackball off of the ring over the overpass. thats our second idea and most likely not the last

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

One of the big problems with ball shooting is that the ball is very elastic, so a lot the force anything shooting into it quickly will be absorbed and wasted. To efficiently shoot the ball, it needs to be accelerated slowly up to a high speed, which is of course very difficult with the size restrictions.

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

We're thinking about a slingshot type design by collecting the trackball into a disc/ring which would shoot the ball over the overpass using the surgical rubber bands in the KOP. We already tried a prototype and it has enough force to get it over 6.5 ft, from the ground. The trick at this point is getting it to fit in the 28" by 38" restriction, but we have some ideas.

Unless of course the guys who want to just make a small car-type robot win the vote on game strategy. Not over my dead body.

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

So I was thinking about this this morning. Unfortunately I'm unaffiliated with a Team this year so I have nobody to try and convince to look into this :)

I don't know if this idea is actually that far fetched. Well, at least not the premise of converting bot kinetic energy into actuation.

Simplifying things down, I was mostly thinking about a mechanism which I'll describe in a few steps as follows:

Step 1), Clear out a lot of space in the center of your robot. This definitely involved a very custom chassis.

Step 2) Imagine a pole going through a ring, so that the ring can slide along the pole. Now, mount this ring so that it can rotate in such a way for the pole to do its business. Do so somewhere near the center of your bot.

Step 3) Attach a large, high-friction foot to the end of this pole.

Step 4) Include some kind of actuated latch to keep the pole locked in a position such that the foot is off the ground.

Step 5) Drive forward quickly, then release the latch.

Step 6) Hope that the pole slides down and plants its "foot" on the floor. As the robot continues to drive forward, the pole rotates about the planted foot, being driven by the forward push of the robot at the location of the rotating ring. The rotation and sliding of the ring allow this to happen "nicely."

Step 7) This should be able to generate 30-40 degrees of rotation, at a reasonably high speed with sufficient torque to drive any mechanism you care to implement. The 100 joule figure I've seen for energy that needs to be imparted to the ball really is not that large compared to the kinetic energy of a decent sized robot moving at high speed.

Step 8) Either the other end of this pole flings the ball. Or, what I think would be extra fun: since the ring needs to be able to rotate to accommodate the rotation of the pole, this ring is presumably attached to a shaft. Any number of gears or other mechanisms could be attached to this shaft and used to drive some other mechanism than depends on a large amount of force being delivered over a short period of time.

I hope that wasn't too confusing. Maybe I'll post some drawings this weekend if I have time.

If someone knows of a team doing something like this I would love to hear any success (or terribly tragic failure) stories :)

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

... and speed up while the ball is in the air, catching it on the other side of the overpass.

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

Why? Don't you like to score points?

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

I think it will benifit us all if you drew out your design.
But i am likeing your thoughts in the design process! :)

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

It just has to go over the bar, right? If it hits the floor it will bounce like crazy and be difficult to control. If you pop it over the overpass and catch it then you won't even have to slow down.

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

I think Gary was referring to the fact that if you throw the Trackball over the Overpass, and then you catch it before it hits the ground or another robot, it doesn't count. So no points for all that effort.

Sean, if you have the time you can always come back to 116 - we can always use your help!

-dave

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

I should learn to keep my mouth shut until I actually look at the rules.

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

We tested it, and and we could push the ball off or throw the ball over with a pneumatic. My team was thinking that we could hold it, lift it, and push it off the robot with the pneumatic. Also, we will probably have another pneumatic on the top of our tower that will push the ball off during Hybrid mode.

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

Ok... this probably creates more questions than it answers... but I think it's enough to help you figure out what I'm talking about if you think through it.

Missing some obviously necessary mechanisms like latch to keep off floor when not in use, resetting device, etc.

If this whets your appetite for more I can try to spend more than 5 minutes drawing. If only I had a white board at home, and different colored markers :)

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

We have successfully used a pneumatic to throw the ball over the rack. Pictures of our test robot and some drawings at http://team1322.org/team_news.htm . The idea is to raise the fork lift to just under the rack and with forward motion and pneumatics you can easily throw the ball over with out stopping. The question is will another team be able to drive in front of us to catch the ball so we don’t have to chase it?

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

Raising the ball and giving it a little lob while staying within the 80" cylinder and dealing with the equal but opposite reaction thing is challenging.

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

cannon...lol jk

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

and that's what makes this all so much fun!

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

Most defiantly our biggest challenge. I wonder how they are going to check this rule. Maybe they will have a large cylinder that you must run your robot up and down inside?