Re: How are you picking up the tetras?
 

but how many can pick off the floor, auto loader or dependent on the human station????

we have an arm type thing as seen...

Re: How are you picking up the tetras?
 

our team was going to go for the simple hook method, but since we thought of it so quickly, we figured everyone else did too ...which turns out to be true...
so we decided to spice things up. our gripper holds all 3 sides facing you off of the auto loader. first we line up by touching the bottom, then we grasp onto the two sides, this gives us much more control of the tetra so we wont lose it while running around the field and getting hit by other bots.
also, it has a certain coolness effect to it, maybe the movie Tremors will stir up your imagination ;) .. we'll post pics later

Re: How are you picking up the tetras?
 

We can...

Re: How are you picking up the tetras?
 

The most efficient tetra manipulator we developed in mock-up used a skewer with a cross bar behind and slightly below the arm beam. We also found that the skewer worked better when tilted 5-10 degrees upward. So far, I've seen lots of skewers with crossbars -- some powered at the wrist and some fixed -- but only a couple that include that tilt.

Ironically, our team voted on a different manipulator in part because the fixed skewer was too simple. Some teammates wanted to be able to flip the tetra over and carry it over the body of our 'bot, others thought it the skewer would require too much reduction in the arm lifter, and, more importantly, it would have made the pneumatics team unemployed.

Re: How are you picking up the tetras?
 

We can also pick it up from anywhere. Our first claw was a simple ball with a shovel at the bottom, but we tried it and it wasn't as easy as we wanted it to be, so we designed a new claw. Here's a pic of it (after we painted it).

Re: How are you picking up the tetras?
 

Just as shown here: http://www.chiefdelphi.com/forums/pictures.php?s=&action=single&picid=10034&directio n=DESC&sort=date&perrow=4&trows=3&quiet=Verbose

Upside, we don't have to lift our arm high to put one on - Also, tetra is secure onece it is in the position shown.

Downside, we may have to come up with an unusual way to load at the human players station. ;)

Re: How are you picking up the tetras?
 

We can as well, although the most efficiant way is the human player. Here's a picture of our claw.

-Daniel

Re: How are you picking up the tetras?
 

We had this idea too. We figured it'd be quite difficult to line up the grabber in the xy plane to pick up tetras from the floor and to score them, so we ultimately went with something different.

How well does your grabber work in terms of lining itself up right? We had a triangular guide in our mock up to help guide the three fingers into the right places.

Re: How are you picking up the tetras?
 

We are using a claw, it looks a little different now that we had to lose some weight but the idea is the same. It uses a 6 inch pneumatic cylinder to rotate it up or down to pick up and release the tetra. This makes it easy to pick up a tetra from the ground, manual loading station or the human player.

Re: How are you picking up the tetras?
 

We use two plates: 1 that is stationary and one that moves. The moving one goes inside the tetra and lifts it into the other plate like this:
Buzz X

Re: How are you picking up the tetras?
 

We haven't actually tried picking it up from the ground, but theoretically (the p-word that the drivers hate) we can do it. The cone helps to center the tetra, and ultimately, if we can get it over the tetra, we can grab it about nine times out of ten. Again, it's much more efficiant to have our H.P. do it, but s/he needs to be tall (I'm 6 feet tall and I need to lift the tetra over my head to get it where it needs to go)

-Daniel

Re: How are you picking up the tetras?
 

This year 88 decided to go very simple... Nothing complexed about it... Though for those of you who have seen us you know how slick we can be... Though I must say the coolest thing about our robot is the 4 foot lead screw we have in it... tehehe... can't wait till the competition!

Re: How are you picking up the tetras?
 

We grab the tetras on the sides when using the autoloader, or have the human player hang it on two bolts in the arm. We do not have the ability to pick tetras off of the ground, or grab vision tetras, but the lack of those abilities hasn't appeared to be of any handicap.

Re: How are you picking up the tetras?
 

We originally went with a forklift design for our grabber. But when we got to competition, we found it was to hard to line up to the auto loader and it was not compatible with the human player. :(

So on Thursday of SAC we came up with a pneumatic that pushes out to hook the tetra, then retracts to let the tetra slide off. But the pneumatic shaft got bent. So down goes design numero dos.

Our third (and luckily final) design is a simple hook with rods coming out either side to stabilize the tetra. It works reasonbly well, but it isn't as good as a well thought out grabber would be. Everything turned out ok though, we played defense for our alliance and got to the finals for the first time in our team's ten year history. :D

Re: How are you picking up the tetras?
 

Our robot has the ability to pick up tetras off the ground but we barely use it. For any of you who have seen our robot you'll know that we depend on our human player to load us up with up to 3 tetras and cap like a maniac.

-Crash