Chief Delphi - "It's the Claaaawww"........ prototype.

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Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Robot Showcase (http://www.chiefdelphi.com/forums/forumdisplay.php?f=58)

- - "It's the Claaaawww"........ prototype. (http://www.chiefdelphi.com/forums/showthread.php?t=89850)

billbo911

24-01-2011 15:35

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

Quote:

Originally Posted by squirrel (Post 1007159)

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.

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.

Quote:

Originally Posted by Chris is me (Post 1007229)

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 originally considered an inside gripper as well. We decided against it for exactly the reason Chris mentioned here.

Josh Fox

24-01-2011 15:36

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

Quote:

Originally Posted by BJC (Post 1007235)

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

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.

MrForbes

24-01-2011 15:59

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

Quote:

Originally Posted by billbo911 (Post 1007252)

The "articulating jaw" adds two things: Much better grip on under inflated tubes, and, Tight grip on normally inflated tubes.

That's a clever idea, glad to hear it works well! As I said before, it's a neat prototype.

Quote:

Originally Posted by Josh Fox (Post 1007254)

I think 2007 would've been a better choice for an inside style grabber since all the tubes had the same inner dimensions.

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.

Josh Fox

24-01-2011 16:07

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. :)

Dracon Phinex

24-01-2011 17:45

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

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

gblake

08-02-2011 14:35

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

Quote:

Originally Posted by Dracon Phinex (Post 1007366)

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

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

EricH

08-02-2011 14:40

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

Quote:

Originally Posted by gblake (Post 1018492)

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

Quote:

Originally Posted by Section 2.2.9

While playing LogoMotion, HOSTBOTS manipulate GAME PIECES to accomplish the objectives of the game. Each GAME PIECE is an inflatable object constructed of 0.3 mm thick vinyl. The body of each GAME PIECE has a tubular cross-section, nominally between 7 and 8 inches in diameter at their narrowest. The GAME PIECES are inflated to nominal size, not a specific pressure.
2.2.9.1 LOGO PIECES
During the majority of the MATCH, the HOSTBOTS manipulate GAME PIECES that are constructed in one of three shapes: a TRIANGLE, a CIRCLE or a SQUARE. The exterior dimensions of the GAME PIECES range between 25 inches (from side to side of the SQUARE) to 30 inches (from corner to corner of the TRIANGLE). The central opening in each GAME PIECE ranges between 9-1/2 inches (for the TRIANGLE) to 12 inches (for the CIRCLE and SQUARE) across. The TRIANGLE GAME PIECES are colored red, the CIRCLES are white, and the SQUARES are blue.

dlavery

08-02-2011 14:55

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

Quote:

Originally Posted by gblake (Post 1018492)

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

.

Chris is me

08-02-2011 15:34

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

Quote:

Originally Posted by EricH (Post 1018494)

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

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.

EricH

08-02-2011 15:56

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.

MrForbes

08-02-2011 16:01

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....

gblake

08-02-2011 19:49

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

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

kgzak

08-02-2011 20:03

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)

Dracon Phinex

12-02-2011 08:59

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::

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