feeding uber-tube pre-game - legal?

The game pieces were way more pressurized (at the Alamo) than we anticipated and we could not manually feed the uber-tubes prior to the start of the game. A referee suggested we put in a momentary manual switch that would power our gripper rollers just enough to insert the uber-tube. He said it would be legal but he is not an inspector. I modified a set of double-pole limit switches to do this and it works great. There is no way they could affect the FMS control of game play, safety etc.

But is this legal?


My only concern would be that it is not controlled through the FMS. Again, I am not an inspector, but I have a feeling they will not allow it.

Not knowing what your robot looks like or how it functions; would it be possible to do something else. Like adding a manual crank to the motor to turn the rollers and grab the tube? This is just another alternative that popped in my head. Again, have no idea if it is feasible with your design.


I would think that this would not pass inspection.

<R48> All electrical loads (motors, actuators, compressors) must be supplied by an approved power regulating device (speed controller, relay module, or Digital Sidecar PWM port) that is controlled by the cRIO-FRC on the ROBOT.

As mentioned above… a switch that you are proposing would allow an electrical load to be supplied/managed through something that is not controlled by the ROBOT.

You could ask Q and A to make sure.
But I am a humble inspector and if I saw it I would consider it to be illegal unless you get some official opinion that would be contrary to that.

i would encourage you to think of a way to feed your manipulator by purely physical and not electrical means at the beginning of the match.


I think <R43> is the more appropriate rule. (Requires direct pathways between speed controllers and motors.)

But in any event, why not just physically disconnect and secure the switch connections prior to your matches? If the switch is a part of the robot, but demonstrably incapable of controlling the robot during a match, you should be fine. (Call it a decoration, and get it inspected in this configuration.) After all, there’s no way to penalize you for having a non-compliant robot outside of gameplay, and during gameplay, you are operating in the inspected (disconnected) configuration, with the motor controlled only by the cRIO and a speed controller.

Incidentally, <R17> only requires that robots be designed to not require power after the match; so that’s no trouble.

Is this what FIRST intended? Maybe, maybe not. They didn’t exactly make that clear.

Or you could have fun and make a 555 timer circuit to control your Jags/Victors with a switch/potentiometer. Have the circuit separate (off the robot) so you can quickly attach it and then set up your robot, and then pull it off before you start the match.

During game play it would be controlled by the FMS, the switch can only be engaged manually and it is momentary. But I can see how and why an inspector would deny it.

The tubes (not hyper-inflated) did load manually during practice but the at the Alamo regional they were inflated to the point they were ready to pop.

Perhaps the spike (that controls the motor with the switches in the normally open position) is shorting the motor, that would make the motors hard to turn. Of course it could be the 100:1 gearing ;o). or maybe I can dis-engage the gears somehow. Making a new gripper is not an attractive option.

It is “demonstrably incapable of controlling the robot during a match”. I’ll run it through the Q&A I reckon.


not legal

Hmmm ok, so that idea doesn’t work.

Is it possible to turn the rollers by hand to “roll/grab” the ubertube? There may be a simple way to add a hand crank on the output shaft to turn the rollers that way as well.

Again, these are just ideas, I don’t want to see you give up. In 2007 we had to take a pin with us to switch the solenoid on the robot to load the keeper (equivalent to the ubertube) tube. Try and be a bit creative, while staying legal.

Hope this helps

We are adding an arm extension (that we did not use week 1 because we lost 9 days to ice/snow during build season) and the gripper will be in a vertical position with the uber-tube sitting in the jaws of the gripper. Hopefully it will pull it in (first thing) during autonomous mode.

If not, we are gonna make it so we can slide a plastic gear out of place so the gripper wheels will rotate then slide it back (secured with a shaft collar). It is a bit tricky but doable.

Thanks for all the advice.