777b Robot Reveal V.1

So guys with version #2 of our sack attack bot built we decided to do a reveal of version #1 of our sack attack bot. We qualified to go to worlds with version 1 and we also won the build award with it. But we found many problems, improvements, and adjustments that could be made, which is why we decided to completely revamp/redesign our bot for worlds. As of now we have won three trophies (two with V.1 and[Tournament Champions and build] and one with V.2[Amaze]) and we are continuing to improve and fix V.2, which we may reveal before or after worlds. Any questions or comments, feel free to ask.


4 393's Internally geared for torque
1:1 gear ratio
Dropped base to prevent sacks from being caught in drive

2 393's Internally geared for torque
2 269'3
Linear Slide gear ratio w/ elastic assist
Distorted 6-bar so the tray tilts forward as the arm is raised 

2 269's 
Two intake wheels directly driven
    Made of tank tread flaps, standoffs, and 6" wheel legs
Polycarbonate tray
    capacity 3-4<br>![Arm Down.jpg|690x500](upload://zYFYF0NioH4SZFYFttkkrYLvtov.jpeg)<br>![Arm Down2.jpg|690x500](upload://eJ38CV1DsqJlBdeJYSVkF4ns9A7.jpeg)<br>![Arm Up.jpg|690x500](upload://jiC5Ut79oFOmB9fKBdC7TRIlFd7.jpeg)<br>![Lift Motors.jpg|690x500](upload://gwNOTN4Y1sAwNPnnsjyCENFSel9.jpeg)<br>![Drive.jpg|690x500](upload://yDF59Jvsuwy3oKwIHtlwbX15BK2.jpeg)

Wow, looks like a pretty solid design guys! Definately built cleanly! I must say though, a capacity of 3-4 seems relatively low. Why exactly is that the maximum capacity? Does the feeder start to throw sacks back out at that point? Or is that just the maximum number of sacks you can lift? Also, do you guys have any video of the robot? Let me know if you can, i might be able to help you guys fit some more field elements in your tray since my robot has a similar intake design and we can fit 8-12 in ours.
Edit: I forgot to mention that you can look at the 944b progress thread to get a better look at my robot if you would like! :slight_smile:

Hey guys! You have an interesting twist on the standard six-bar design.

How do the linear slides perform when compared to a standard six-bar? I’ve personally found them to be quite slow and inefficient, have you managed to overcome those issues?

I also notice you have a low-slung drive, how well does that work?

Additionally, you only appear to have the back two out of your six wheels driven. Why did you build your drive that way?

Lastly, I see you have taken the rubber outer coating of a high-friction wheel and placed it around a sprocket. What were your motivations behind that?

Thanks. :slight_smile:

First off thanks for the complements on the robot, we agree in the fact that 3-4 is a very small capacity and that is a big reason that we decided to change the design around, in addition it did begin to spit out the sacks after we got about 5 in the tray (which was our capacity). We do not have a video of the robot, sorry about that, but you may be able to find one online (we participated at Dockbots '13 and the PA State Championship, I will look and see if i can find one). And I will be sure to chech you guys out thanks again!

We have found that the linear slides work very well for us they give us good power as well as speed and we haven’t had any issues with them so far. I think that when you mount them you have to be careful on where you mount them, we tried to mount them as far away from the arm tower as possible so we got the max amount of lift and torque from them. As for the low drive it was a very beneficial thing to have as far as the center of gravity, we never had a single issue as far as tipping goes but sacks did get caught in the front and rear of the drive, but that could be fixed with a little more plating. Any way as for the high traction “wheel”, if you just switch the treads out on the normal 4" wheel you can see that it is actually smaller then an omni wheel, so we found, through another team 3086, that with the tread on the largest sprocket it makes it the same exact size as an omni wheel and you get a lot better traction from it.

Thanks again for you interest!