Re: Arm Designs
 

i would go for a cross design. The vertical would press on one edge of the triangle. The horizontal would go through two holes somehow. Then sort of pick up using the pivot points, then that would lift the triangle up at an angle, making it easier to put the tetra on the goal

Re: Arm Designs
 

Has anyone considered a three pronged hand at the end of an arm? Any point of contact would result in the tetra being grasped in some way. What do you think?

Re: Arm Designs
 

When I was on team 535 (2001 rookie year) we had a robot with a forklift mechanism. With our arm we could lift the large ball 11' into the air every time :ahh: And we were able to keep it within the 60" spec.

Wayne Doenges
CAD Mentor

Re: Arm Designs
 

wiat... are you referring to your forklift as the arm? and if you have any pictures please, dont refrain from posting them.

Re: Arm Designs
 

My fear is that when you are trying to place the tetras and when your arm or forklift or whatever is at its highest point, a little bot will come over and knock you over. Due to your arm being high up, you would be very vulnerable. Besides, when you stack those tetra's you have to remember that the height of the stack will be increasing and you have to make you sure your bot can go higher than the height of one tetra stacked.


GO 1403!!!

Re: Arm Designs
 

That is exactly what i have been thinking. It would seem like it is impossible to miss the Tetra because no matter what you can get it. It would also allow for a greater percent error as far as control is concerned because you'd have a greater chance of getting something.

Re: Arm Designs
 

Arm design this year is going to be much more important. Having a robot that the controller can use to react quickly to the game will be cruical this year. Ease of use and fast response times will be very important issues.

Does anyone have any ideas about a non-forklift style arm that could be useful?

Re: Arm Designs
 

That's what 1474 has been looking at for a design. I'm not sure exactly how it'll all work out but we're hoping for the entire arm to be able to rotate around the chassis of the robot.

Re: Arm Designs
 

Our team seems to have decided that the bendable, traditional arm would be better than a forklift in that it allows for more precision than a forklift type arm would.

Re: Arm Designs
 

it depends on the chassie but my preference is a lift because it doesn't move the cg out it just moves it up a little. that is just my opinion.
hope u do well see u at the comp

Re: Arm Designs
 

For arm design I was tossing around the idea of something similar to a bucket truck arm (that's a bending arm isn't it?). My team hasn't taken much fancy to it but I think that it could give a lot of flexability in motion when the tetra is so high in the air.

Here's an Example of what I was thinking (This isn't a robot picture, just an idea). Just my thoughts though :)

Re: Arm Designs
 

After my earlier post I took some time to think and came to my senses: an arm's the way to go. If you've got a forklift then you need to be right next to a goal to score, so a robot could just get between you and the goal. But if you've got an arm you can reach over another robot if it's in your way. The hard part is going to be designing a mechanism for the end of the arm to effectively pick up and score the tetras.

Re: Arm Designs
 

our team did some calculations and discovered that with a folding arm, there is a tremendous amount of torque placed on the main joint while carrying a tetra. :(

Re: Arm Designs
 

reaching over a 38" long robot and then reaching 10-14" into the goal (assuming you hold the tetra from about the end) is going to put your CD pretty far forward. Don't expect to be safely reaching over an entire robot without something to stabilize you.

Re: Arm Designs
 

There is a lot of geometry here to play with and work out. I wouldn't rule out anything just yet. Every year I see some one else figured out how to do the killer strategy that I couldn't figure out how to accomplish.

Also tetras aren't had to pick up. Play with them for a couple minutes. It took us all of 5 minutes to come up with a K.I.S.S. method for doing it once we had a couple made.