Happy New FIRST Year to All!
Our team’s rookie year was 2008, a year after Rack ‘N’ Roll. At first glance, it seems like the manipulator designs that worked well for that game should work well this year too. Us newbies would appreciate hearing what worked well and what didn’t work well for Rack ‘N’ Roll.
Mahalo!
Roller claws are an infamous tool within FIRST
Try a CD media search for 07 for some of the big name teams you know of, most of them have a roller claw I believe.
This is worth a perusing as well if you can find a copy at a library or find someone who you can borrow it from.
We were quite successful in 2007. Regional Champions in Portalnd Oregon and Finalist in Philidelphia. Attached you will find a picture of our Robot. Team 272. Simplicity is the key(KISS). The tower was extremly fast and the programming exceptional allowed us to know when a tube was within range. Go the www.thebluealliance.net and look at the Oregon Regional from 2007 to see our robot in action. My team is already considering a similar design obviously there is the issue with the bumper being across the entire perimeter but we believe that there are work arounds. Any specific design questions from this model email me and I can be more specific. [email protected]
http://www.chiefdelphi.com/forums/showthread.php?threadid=88436
http://www.chiefdelphi.com/forums/showthread.php?t=55826&highlight=best+tube
check out these threads for information.
07 was all about active tube manipulators. Any team with a passive “claw”, my team for example, had a hard time picking up anything but a perfectly inflated and just in the right spot tube… The need for some devise to “suck” the tube in is crucial
Once we changed our arm mount for it, we had a lot of success with a grabber sort of the like a reverse umbrella. As long as it landed anywhere inside the tube a pneumatic firing would expand some flexible extensions and it would grab the tube. Then it could drop them on the rack. The biggest problem we found was the arm being unsteady because it was so light. Making it hard to quickly line up to pick up a tube from the ground. (A problem of our creation since we were trying to save weight for a very cool ramp we ended up not using.)
You have to remember, manipulators have to start inside the bumper zone, and 07 robots didn’t need that.
That is a great point! Your arm needs to be fully within the frame perimeter, so claws like in 2007 might not always work.
Great point!
Our 2007 robot had an arm that actually did start within the bumper zone. Here’s a picture
http://aceshigh176.org/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2866&g2_serialNumber=1
As you can see, the wrist and elbow joints of the arm folded allowing the manipulator to fold into the frame perimeter.
Our manipulator was made of delrin. The bottom piece ran parallel to the floor and slid under the inner tubes. The top pieces was rounded to clamp around the tube, and had rug stop material on it to grip. The whole mechanism closed with the stroke of a pneumatic cylinder.
I think that one of the big differences between 07 and this year is the room that the robots had to place the tubes in 07. The grippers were able to extend back to chains. This year the wall will restrict how far the manipulator will be able to reach back.
They still had to be within the required 28x38x(48/60/72) volume at the start.
The big difference is the bumper requirement, significantly making it harder to pick tubes up off the ground. 1126, and many of the elevator lifts could be modified for this year.
In 2007 the Rack posts had a 9" diameter disk on the end; with tubes having a 10" ID, many teams decided that a manipulator that gripped the inner diameter of the tube would interfere with placing tubes on the rack. Thus we saw a lot of teams with grippers, and not as many with inner-diameter-grabbers.
Nice photo, thanks. I see what the upper elbow joint is made of, but can you describe the lower elbow joint for me?
I think another difference in the game that must be taken into account for this year is how the robots are (likely) going to retrieve the game elements - in 2007, it seemed like they mostly had to pick them off the ground (just my perception - I wasn’t around back then) whereas this year I’m guessing the primary method of retrieval will be through the feeder slot.
Back in '07, nine rings of each color started on the floor (stood up against the Alliance Wall), and tubes could be passed into the field via vertical slots.
However, my guess is that this year like '07, LOTS of tubes will be hurled over the Alliance Wall.
This year there’s an opening in the Alliance Wall (the Feeder Slot) where you hand off tubes to the robots. Of course, if you drop a piece you will need a way for the robot to pick it off of the field.
Yes, I know there’s a slot; there was a slot in '07 as well (vertical compared to this year’s horizontal). However, the slot is at the end of the lanes, which quite frankly are a long way to go to get a single game piece. IMHO, lots of pieces may be thrown over walls to speed up the process, even though it will admittedly risk your opponent getting the piece you threw in.
Both of these points are valid. When my team goes to pick a human player, I’ll definitely recommend lining people up, putting a 8ish feet wall in front of them, and then seeing how far they can chuck it. Why have your robot make the 50ish feet trip if it doesn’t have to.
On the other hand, why take the risk of an opponent robot stealing one of your rings when you dont have to.
