Banebot Transmission Issues

[Paul Copioli]

O.K. I have kept quiet long enough.

The bottom line is that FIRST had a solution for the kit drive train that could also be used for an arm. They used it for two years with the only reported failures being from teams who did not lubricate the gearbox. It was designed and TESTED before it was placed in the kit. A 120 lb. prototype mule was created, beat against a wall, durability tested and shipped to Manchester in August of 2004 so they could do more testing. It was already in the kit and no more work had to be done.

The Banebot solution was a cost down effort by FIRST, plain and simple. This is O.K., but testing needed to be completed.

My question is why wasn't the same rigor a MINIMUM requirement for the BaneBots solution? If this was not tested on an actual robot before delivery to FIRST, then that is a huge oversight ... HUGE!

Now Dr. Joe,

You and I agree about 99.5% on things engineering, but you and I are polar opposites on this one. You made this comment:

I believe that the higher ratios are even useful, but more for speed reduction not torque increase. The output joint is the same for every ratio. If the torque gets too high it will break that joint.

C'mon. You get the torque increase as a result of the increased ratio. It is there whether you want it or not. While you can design your arm to not need it it will always have the ability. If your arm gets stuck, wedged, etc. then the motor will output that torque and you will have almost nothing to say about it. Gearboxes must be designed so the motor is the weak link. If you are reducing the FP (or Banebot) motor to get to a reasonable speed, then you better design the gearbox to handle the torque.

If BB offers a 256:1 ratio that is meant for a specific motor, then it better be able to handle the torque. If they offer a conversion kit to add a second CIM motor, then the gearbox better be able to handle the maximum possible torque the CIM motors can output.

If the gearboxes are not designed this way, then we will have a lot of robots that can make a perfect circle with their drive base.

I am now officially worried about teams using the new kit transmission with 2 motors. My calculations do'nt look good ....

-Paul