4405a Robot Reveal


I thought I would post my robot for some last minute criticisms and comments before our first tournament in a couple of weeks. Your questions and suggestions are most appreciated! So, without further introduction, allow me to introduce “Yossarian”

-Steel drive base, aluminium arm
-four 393 motors on drive (1:1)
-four 393 motors on lift (5:1)
-two 393 motors on intake
-chain bar arm lifts in about 1.5 seconds
-goes over the bump like it’s not there
-3 bucky ball capacity, 1 big ball pickup
-“gateway” style intake, picks up big balls by reversing direction and pushing them up over the top
-does not hang

…and some more pictures…

(I know the 12tooth gear is shifted in the lift, it was fixed shortly after the picture was taken)

Once again, anything you offer is greatly appreciated!

I love the chainbar. Fantastic work.

I’m assuming you use a wall or a hard object to pick up a large ball?

Great job. Any videos?


There is a method that might work for you to low hang, which is discussed in this thread:

Your robot looks good, but you might want to clean up the wiring a bit.
Last photo, second post. Here is another way to do it: (Not necessarily better.)

Have you had any tipping issues?

Unique large ball intake…
I’m curious, why didn’t you go with the standard high-rollers?

No videos yet, it was just finished. We’re hoping to record some scrimmages with our other teams and post them soon.

The large ball has to be picked up against a wall for the rollers to intake over the top.

Thanks for your encouragement!

Thank you for the wiring advice, they’ve been getting caught in the drive and lift so I was wondering of a better way to do it. The robot does tip, but only under extreme cases. Our driver is pretty good at keeping it under control. Just in case, though, we have a mechanical stop so the arm doesn’t go over backwards (the last picture from the first post shows a standoff behind the chain. this stops it from going over center).

We’re going to focus on hanging next and the diagram there seems to be a good option. I was worried about too much torque on the chain bar previously.

As far as the big ball intake goes, we had the higher rollers on it for a while instead of the bevel-geared roller. They worked fine, but (for us, at least) the stress on the metal made us nervous. We saw our B-team had a single horizontal roller and was able to pick up the big balls against the wall, and decided to incorporate that into our design.