"It's the Claaaawww"........ prototype.
 

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.

http://www.youtube.com/watch?v=QMjZ1swhchc

http://www.youtube.com/watch?v=wMU7VPON7M4

Re: "It's the Claaaawww"........ prototype.
 

That's a super nice prototype. Good enough to be the real thing.

Re: "It's the Claaaawww"........ prototype.
 

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:

Re: "It's the Claaaawww"........ prototype.
 

That looks awesome actually. Fantastic work by you and your team! Are you planning on making the final version out of aluminum or polycarbonate?

Re: "It's the Claaaawww"........ prototype.
 

Yes. The fingers will be polycarbonate and the linkages will be aluminum.

Re: "It's the Claaaawww"........ prototype.
 

she's a looker, thats for sure. For some reason a lot of robots this year look awefully violent...it's awesome.

Re: "It's the Claaaawww"........ prototype.
 

neat prototype!

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.

Re: "It's the Claaaawww"........ prototype.
 

What was wrong with the outside grab that year?

Re: "It's the Claaaawww"........ prototype.
 

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.

Re: "It's the Claaaawww"........ prototype.
 

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 :)

Re: "It's the Claaaawww"........ prototype.
 

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.

Re: "It's the Claaaawww"........ prototype.
 

Haha that's awesome, we cut ours from a bucket too! Now I gotta go find some pictures of their bots.

Re: "It's the Claaaawww"........ prototype.
 

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.

Re: "It's the Claaaawww"........ prototype.
 

We didn't have an inside gripper in 2007. It pinched around the side of the tube from the outside.

Re: "It's the Claaaawww"........ prototype.
 

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.

Re: "It's the Claaaawww"........ prototype.
 

Jim,
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.

Re: "It's the Claaaawww"........ prototype.
 

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.

Re: "It's the Claaaawww"........ prototype.
 

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.

Re: "It's the Claaaawww"........ prototype.
 

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. :)

Re: "It's the Claaaawww"........ prototype.
 

It might work. Is the prototype lighter than the final?::rtm::

Re: "It's the Claaaawww"........ prototype.
 

Gripper folks - Please let me sneak in a side topic - Is the triangle logo piece's tubing smaller than that of the Circle and Square?

Our current 5th Gear models have 8" tubing in the Square (sides) and Circle, and 6" tubing in the Triangle (sides).

Blake

Re: "It's the Claaaawww"........ prototype.
 

Not supposed to be smaller. The Triangle is just longer corner to corner to compensate.

Re: "It's the Claaaawww"........ prototype.
 

Blake -

Yes. The circle and square are a uniform thickness around the central cross-section of the shape (i.e. for the purposes of discussion, if the pieces are lying flat on the floor, the "height" is the same all the way around). The triangle is distinctly different. It is not a simple extruded shape. It is thinner along the edges of the triangle, and thicker ("taller" in the "lying on a flat floor" context) at the corners. When viewed from the side, the inflated triangle has a slight dumbbell shape. The difference in thickness between the middle of the edge and the corner can be as much as two inches.

-dave


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Re: "It's the Claaaawww"........ prototype.
 

This is absolutely not true. The triangle is distinctly different than the circle and square in shape. This particular aspect of the game challenge is one my team and many others have struggled with for a long time.

Spinning tubes in a roller claw is a LOT harder if the tubes are drastically different thicknesses.

Re: "It's the Claaaawww"........ prototype.
 

I said "Supposed to be". According to the Manual, there is not supposed to be a difference in the tube diameter between the types. If there is one, the Manual needs to be updated with that information.

Re: "It's the Claaaawww"........ prototype.
 

heh...supposed to be.

We gotta build the robot to work, so we decided to use an inside grabber. The inside of the tubes is roughly the same size, and having a pneumatic actuator with limited force lets the claw grab them all, even if they're quite deflated.

Plus it's a lot easier to design and build, and since we have a lot of new young students this year....

Re: "It's the Claaaawww"........ prototype.
 

Triangle Tube shape is a little irregular - Got it - Thanks!

Re: "It's the Claaaawww"........ prototype.
 

We are using an inside gripper and found it easier to pick up tubes. The way ours is designed is that we run into a tube, hit a button and our robot automatically picks up the tube. Also, we found that with an inside gripper we could pick up tubes that have absolutely no air in them (although not by running into them since we would drive over them)

Re: "It's the Claaaawww"........ prototype.
 

I do believe that the Triangle is smaller than the Circle or Square. I will get back to you on this.::rtm::