Preloading uber-tubes

So my team has constructed a claw to hold and place tubes during a match that uses a window motor. The problem is that the window motor cannot be back-driven so loading an uber-tube for autonomous requires it to be powered closed. we considered wiring a switch into the circuit so the claw could be opened and closed without connecting the OI, but have been unable to resolve the debate over this being allowed by the wiring rules. What is the best / legal way to handle this situation?

The switch will almost certainly be illegal.

I’d say you have two options:

  1. If your claw is at all flexible, you could just push the ubertube on to it. Since both the tube and your claw could deform, that would accomplish the goal. This is substandard, though. If this is the situation you’re in, you’d also have problems removing a tube at the end of a match.

  2. The more preferable solution would be a way to manually open the claw, like a pin or a spring. That way, you could open the claw without a motor for the start of the match, and be able to remove tubes at the end of a match.

If you can provide a bit more detail about your mechanism, I think the folks here will be able to better help you.

Another thing you could do is leave the claw open for pre-loading and have the robot close it first thing in autonomous.

There is the option of Tethering your robot to manually open the claw before the match and sitting an ubertube in it, then at the start of the match, the claw automatically shuts. This solution is really Dependant on the orientation of your claw and how much movement your robot will be subject to after the tube is inserted and before the claw closes.

Whoops, Phoenix Fire beat me to the post.

One more thing to pursue is asking the Q/A when you’re given the Ubertube for preload. In some previous games, you were given the game piece to preload prior to placing your robot on the field, which allowed enough time to tether and load the game piece. I don’t know if this will happen this year though.

It would alter the power flow, which is not allowed.

Just remember: the rule is “in contact”, not “in possession”. All you need to do is make sure you’re in contact.

Ok so the plan the team came up with today is to have a set of disconnects between the victor and the speed controller and have a small battery wired to a switch and a set of disconnects(not part of the robot). so when needed we could unplug the motor and drive it individually then plug it back in for the match. I told them this might be considered an alignment device what are your thoughts?

Do you mean between the speed control and motor? I don’t think this would be considered an alignment device.
The one thing to worry about though is how long it would take you to do this. If it takes a significant time, they might ask you to change it so that the matches aren’t delayed.
If you are worried, ask the Q/A.

I still think a small piece of code at the beginning of autonomous to close the claw would be easier.

You’re getting power from a device that is not the onboard 12V battery.

You’re modifying the power pathways of the robot.

You could easily forget to plug the motor back in.

You’re using special equipment on the field that isn’t needed for a disability.

You have two speed controllers controlling one motor (victors* are* speed controllers).

At least three of those are legality issues.

Put some other form of claw-opener on board. Or, start with a slightly open claw if that’ll fit in the box.

Well The Power supply and pathway would not be during a match so those should not be an issue, and the is no need for two speed controllers at anytime.

The additional equipment on the field is a valid concern but my interpretation of the last update was that applied to the alliance station and this device could be left on the robot cart.

I’m not actually with the team this year but as they explained it to me the claw folds into the edge of the robot frame in the starting configuration and as such can’t be left open.

Have you tried just squeezing the tube into the claw? Even filled tubes are a little squishy.

deflate the tube a little put it in, then blow it back up?

This is a bit questionable. I can’t think of any rules off of the top of my head, but I’m sure someone will interpret it as a violation of the rules. I’d ask this in the Q&A if you’re planning on doing it.

Also, there are still two weeks left until ship. If you’re robot is far enough along that you’ve begun autonomous testing then you probably have enough time to redesign or modify the claw in such a way that you can easily pre-load an ubertube.

Maybe so, but how are you going to pass inspection? That’s not done on the field during a match either.

depending on the specifications of your claw within the rules, the easiest thing to do would be to have a hinge with a pin so you can open the claw a little then close it. or like other people said just put a small piece of code in to close the claw as soon as the robot autonomous starts.

<R48> says your robot cannot have an alternate means of powering a motor

remember that you also have to be able to remove tubes that are stuck in your gripper at the end of the match.

what we did last year was have the electrical team make us a small pwm signal generator that connected into a quick disconnect on the robot, got power from the robot’s battery and used their speed controller.we used it to pretension our kicker and adjust the position of our winch. it was allowed then under the condition that the signal generator could not be brought onto the field itself as that would be considered having another device control the robot. if you are using can bus this would be a bit more difficult as i don’t think the rules allow having both wired at once, but it is still doable.

Last year’s rules and rulings do not apply this year. What may have been allowed last year under conditions may or may not be allowed this year whether under conditions or not.

If a pole to retrieve the Minibot is considered special equipment, even if it could have been standardized to every Minibot, then a device that alters power pathways (or alters control signal pathways, bypassing the cRIO) for a specific robot could easily be counted under the same category.

I would suggest asking Q&A if you could have a device to power the motor before the match, if it was a) off-field and b) on-field before and after the match times.

I also have a quick question about this subject.

Our claw is powered via pneumatics. Could we have a valve that would block the air to the solenoid to the claw while we preload the air? This way we can force it open, place the tube in, then turn the valve to pressurize it. I can’t see why this wouldn’t be legal.

(Sorry for slight topic hijacking)

as someone else mentioned before, just have your claw stay open and close as soon as autonomous starts. its the surest bet you got