How to get the ball over the overpass!?

[hunter7]

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

[EricH]

Originally Posted by hunter7

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

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.

[lopz056]

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

[ubermeister]

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.

[Lynx34]

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.

[jleibs]

Originally Posted by Swampdude

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.

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

[seanwitte]

Originally Posted by Swampdude

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.

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

[GaryVoshol]

Originally Posted by seanwitte

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

Why? Don't you like to score points?

[ar2]

Originally Posted by jleibs

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:

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

[seanwitte]

Originally Posted by GaryVoshol

Why? Don't you like to score points?

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.

[dlavery]

Originally Posted by seanwitte

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.

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

[seanwitte]

Originally Posted by dlavery

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

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

[Cartwright]

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.

[jleibs]

Originally Posted by ar2

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

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

Originally Posted by jleibs

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.

[joeweber]

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?