Bouncing TrackBalls

[GBilletdeaux930]

Alright so i havent been able to play w/ the trackballs much since teamwise, we havent blown it up yet, kickoff wise... people were like stealing from ur hands 2 seconds after u got it so yea...

How much do the trackballs bounce? Cause i was thinking...if u hurdled it over the bar...how hard is it to regain control of it if it bounces quite a bit...

[T3_1565]

lets say it won't stay still once it drops 6 1/2 feet lol

[popo308]

They are verrrryyyy.... bouncy.

We were punting it 7 feet just to see how far it bounces and it easily bounced back up to 6 feet.

[GBilletdeaux930]

So after the first lap...when probably half the bots have tossed them over...were just going to have bouncing balls everywhere...crushing the less sturdy robots...

I wonder how quickly bots are going to be able to (re)gain control of a ball then...ugh this is going to be exciting...

[danshaffer]

Unfortunately we dropped the ceiling in our lab (formerly ~30ft) to the point where we can only get the trackball's bottom about 5' off the ground, but our (limited) bounce testing shows that they have a coefficient of restitution (bounciness) of somewhere between 1/2 and 2/3, that is each bounce is about .6 times as high as the previous.
That sounds like a lot of... fun.

[GBilletdeaux930]

So about 4 feet... .6 times as high each bouce... after about 4-5 bounces it might be able to grab IF it doesnt bounce out of the arena... given the only open areas are where the robots are dragged in...

Im to tired to do the math oh how long it would take for it to hit the wall and start bouncing back...parabolas and such...

This might actually give an advantage to robots that are trying to grab and carry them... robots pushing them will have to try and follow it around as it bounces off of walls and robots and such. I dont know that was probably obvious beforehand im just tired... Man only like 2 days in and im already behind on sleep...

[danshaffer]

Well basic kinematics shows that the height of each bounce doesn't matter at all for the time that it will take to hit the wall, just the velocity with which it is released as it is hurdled.
The bouncing height will increase the contact/normal force and thus the friction, but the ball wasn't going to be sliding anyway, presumably it would just start rolling.

[GBilletdeaux930]

ok... so my mind doesnt function well when its tired... lol

so anyways...any ideas on how you would control this or beable to gain control of it while it's bouncin...

[danshaffer]

well you either have to have a solid grabber to take control of it or otherwise just have a big pusher and don't worry about the bounces...

[Jake177]

One easy way to deal with grabbing a moving object is rollers. With a powerful enough mechanism, all you would need to do is touch the ball to grab it. The problem is designing a powerful enough mechanism.

[GMKlenklen]

http://www.youtube.com/watch?v=o4bAuLg7ZmE

[tuzzer]

It doesn't seem too bad. It's not really that hard to catch

[Daniel_LaFleur]

Originally Posted by GBilletdeaux930

Alright so i havent been able to play w/ the trackballs much since teamwise, we havent blown it up yet, kickoff wise... people were like stealing from ur hands 2 seconds after u got it so yea...

How much do the trackballs bounce? Cause i was thinking...if u hurdled it over the bar...how hard is it to regain control of it if it bounces quite a bit...

Dropping the ball from ~6 1/2 feet it bounced ~3 1/2 - 4 feet. In addition, the bounce was not as predictable as we would have liked it to be. I think hurdling will only be 1/2 the problem (and thats a big problem) ... with recovery of the ball being just as difficult, especially if it lands on another robot

[team1203 4life]

[quote=How much do the trackballs bounce? Cause i was thinking...if u hurdled it over the bar...how hard is it to regain control of it if it bounces quite a bit...[/QUOTE]

we just blew our ball up and they are extreamly bouncy just rowling it toward a wall a low speed and it jolted backward

and if you are thinking of regaining controll of it after it was thrown over the hurdel good luck with that because it will be all over the place especialy depending on how good your driver is

[GBilletdeaux930]

Heres an idea...if you used mecanum wheels and an arm...u could chase it down with the wheels easily without having to move your arm from side to side...then once its in front of u try and push it down to speed up the bouncing process w/ the arm...

dunno how easy that would be but its a thought...