Here are a couple of quick clips or our prototype claw. The final will be much lighter and the action will be faster. The beauty of prototyping it is we found some very interesting mods that really make it work well.
That’s a super nice prototype. Good enough to be the real thing.
Yep, I’ve said the same thing!
But there is a little problem. One of our team “rules” is:
No wood on the robot!!
Some rules are made to be broken.:ahh:
That looks awesome actually. Fantastic work by you and your team! Are you planning on making the final version out of aluminum or polycarbonate?
Yes. The fingers will be polycarbonate and the linkages will be aluminum.
she’s a looker, thats for sure. For some reason a lot of robots this year look awefully violent…it’s awesome.
We have a rule: We make no rules about what materials we can use, the GDC does that for us. Our 2009 robot was made mostly of plywood and plastic pipe, and it was the most effective robot we have made. It even had a couple wood 2x4s in it!
Our prototype has two pieces of plywood also, but they work differently. We used a pneumatic, outside, single point grabber in 2007 and were not real pleased with it, even after a redesign between regionals. We’re going for the inside grab this year, wish us luck! and when we get it actually grabbing a game piece under computer control, we’ll put video up.
What was wrong with the outside grab that year?
There were two problems. We did not anticipate how variable the tube inflation would be, and the claw just did not get a good enough grip on tubes that were a bit soft. The second problem was that the tubes could move sideways, they did not want to stay properly oriented.
I think the inside claw will help with both of these problems. This year the goal pegs have a much smaller end cap, so the tube placement action will be different, and more appropriate for an inside grabbing claw.
For the original poster, I suggest you have the students try to shake the tube off the claw by moving the “arm” sideways as if it were on the robot, and the robot were maneuvering as robots do in real games. See if you can hold onto the tube, and that the tube does not move around too much. It could be that this design does work just fine.
Since it was my freshman year in 07 and we did not travel to Atlanta that year, I didn’t see many other robots from that year. What other teams were there who had inside grippers? The only one I had any knowledge of other than our own was 25’s. I definitely liked that robot haha
If I recall correctly, both 47 and 33 had “inside grippers,” with Chief Delphi using a bucket cut in half as part of their end effector.
Haha that’s awesome, we cut ours from a bucket too! Now I gotta go find some pictures of their bots.
My big concern with an “inside” grip is lining up the gripper on the tube - that seems a lot harder than driving into a tube and “chomping” it.
We didn’t have an inside gripper in 2007. It pinched around the side of the tube from the outside.
Yes, it’s an important concern. We’re using the approach of having the pivots for the “fingers” far apart, and the fingers close together to form a dull triangle when the gripper is not gripping a tube. Then this “point” can be used to help guide the tube and gripper together, so aim is not very critical after all.
Thanks for the suggestion. In fact, we have already tested this. There is another video that I didn’t post that shows the gripper without one simple modification that has made this version SO MUCH better. The “articulating jaw” adds two things: Much better grip on under inflated tubes, and, Tight grip on normally inflated tubes.
We originally considered an inside gripper as well. We decided against it for exactly the reason Chris mentioned here.
Ah, my mistake. 47 is the only one I recall then.
I think 2007 would’ve been a better choice for an inside style grabber since all the tubes had the same inner dimensions.
That’s a clever idea, glad to hear it works well! As I said before, it’s a neat prototype.
heh…that’s why we are using it this year, because from what we can see the inside is the most consistent part of the 3 game pieces. I guess we all see things differently.
Now that you mention it, I based that statement on a hunch, which obviously isn’t the best choice for decisions making in the engineering world.
Thinking about it a little more now, I can see using an inside grabber that expanded to fill up the middle actually seems like a pretty good idea. If it’s a circular shape, then you’re guaranteed that the inside edges of the tube will make contact.
So I will reserve judgement for now, and best of luck with your design.
It might work. Is the prototype lighter than the final?::rtm::