Rookie Team Redesign

[joelg236]

It's that time of year again... Two days left in build season and my rookie team is left in a precarious situation.

Our last 6 weeks were spent on a "rotational lifting" design. The idea was that this was much simpler to accomplish, easily diagnosable and a K.I.S.S. type way to do things (even though we could only stack 3 totes + a bin).

And until today, it worked well, especially considering our resources and manpower (very very tight on budget).

The design went like this: 80-20 framing on AM14U2, a minCIM geared 100:1 direct driving a ~30 inch arm that has lexan clips that fit under the lips on totes, and around the bin.

But over the last few weeks we've slowly been leading towards the issue that our versa planetary gearboxes are breaking - even in what could be considered "normal" game situation use. Lifting stationary and without other factors, there isn't much of an issue. But when driving and just generally being more "busy", we've managed to break the sunflower gears three times, as well as (apparently, no visible damage) the housing 3 times.

And we're out of supplies to replace the ones that broke today.

We had thought our issue was solved a few days ago when adding some thicker tubing to a "leverage bar" on the back of the arm (picture). Well today proved that wrong.

I'm wondering if anyone might have some advice or experience in this kind of situation. It's mostly out of the cards to "buy a solution", and our machining abilities are limited but not impossible. Advice regarding design, the team, strategy, or just in general would be appreciated. I would love nothing more than for us to "succeed", in the sense that we end with something we're proud of.

Ideas I've had:

• Similar to 148's "HP bot", we could act as a backstop for 2-stacks, to make things quicker for HP bots that are out putting stacks on platforms
• Bring our arms lower and closer to centre for less torque on the motor, limiting how high of stacks we can make (we don't have the gearbox for this, but maybe a PG188 or similar could do it)
• Bulldozer noodle removal

It's worth noting that yes, I am aware of the fact that the miniCIM with 100:1 is not advised on VEX's website. We made that decision, aware of this potential problem. It was necessary to get enough torque with the arm length we wanted. I thought long and hard about it, and obviously hindsight is 20/20.

Thanks!