Ground Gear Intake speeds

I was wondering what speed teams ran their ground intake at, what type of intake wheels you used, how that worked for you through the season.

Also, I was wondering if different motors affect intake performance (though I imagine the difference wouldn’t be too large).


For our off season intake we ran a 775 through a 9:1 Versaplanetary to 2 inch compliant wheels and it works great. After practicing for pretty much 2 hours straight the motor only gets slightly warm. Only only problems we have are with our HDPE fin at the front but that will be improved.

Here is a subpar video that shows a visual of the speed.

We ran a BAG motor through a 10:1 Versaplanetary to 2" Compliant wheels.

We used a BAG on a 5:1 VP with 1.625" Flex wheels. Probably could have gone with a 3:1 and been fine, but a 5:1 was plenty fast. We are using the current to determine when we have acquired a gear. Using a Pro in this application geared for that fast is probably not great because of how hot our motor runs due to nearly stalling it out every time we acquire a gear. However, the code on our robot does an excellent job turning the motor off before any serious damage is done to the BAG motor.

So 18730 RPM / 9 (:1 ratio) * 2 (inches diameter) * 3.14 (for circumference) /12/60 (to get to feet/second) * .85 for some speed loss fudge factor = 15.43 feet/second wheel speed.

Now, the old rule of thumb was “double your drivetrain top speed on floor pickups”. But considering you’re most likely getting your gear within a couple feet of an immovable object (either the wall or the airship) that much irresistible force feels about perfect.

We used two Andymark PG27 gearmotors driving Banebots 2-7/8" orange wheels. This “meshed” with the gear teeth.

It worked well throughout the season. Sometimes the gears bounced away though. Check the video:

We test the pickup to determine the ideal speed for the intake. It is different every year and for every object. Then add or subtract the speed of the robot to make picking up on the run more efficient.

We used a 775 pro on a 7:1 reduction which ran a 2 inch roller with surgical tubing floated over it. It worked very well for us and I’m very happy that we had it

Are those gearmotors the ones from the kit? That has to be the most simple and innovative gear pickups I have seen.

We used a BAG motor with a 4:1 on a VP with 2" AM Compliant wheels. Worked great.

We used a BAG on 9:1 with 2" compliant wheels, we went abit slower since we had bottom wheels that ducked the gear in (like 179) and they needed to be able to grip the gear, instead of kicking it away.

minicim without reduction.
god knows why, but it worked amazing
we had some current issues at first, but we solved it

  • never mind, it was for fuel intake. i didn’t noticed the title

Thanks so much for all the info! I see that compliance wheels would be the best choice for this because of their compliance (hence the name), but I was planning on using banebot wheels in the most compliant durometer, and was wondering if I would have to gear the motor differently? (My personal though was that we’d have to gear it slower because the wheel won’t flex much when intaking the gear, so to avoid pushing the gear, you would gear it slower. But I don;t know if that’s right or not.)

Thanks again!

Our ground gear intake was very effective from Week Zero, all the way to Champs. Our ground intake system was originally only powered by 1 BAG motor, going through a 9:1 VP gearbox. This powered over 40 1-3/8’’ orange bane bot wheels on the base, and 5 2-3/8’’ blue bane bot wheels at the same time using a belt system and shared jack shaft. This worked for a while before we added a separate 775pro geared at 10:1, but belted up 3:4 for the 5 blue bane bot wheels.

We found this system to be extremely effective. Before the FRC build season, we studied Einstein winning robots, especially ones from 2015 since gears and totes are rigid plastic game pieces, and noticed an abundance of orange bane bot wheels and flexible moving intakes arms. We have since incorporated orange banebot wheels into our inventory, and have a bane bot wheel “staff” of all of our extra wheels.
Here are some action shots from, our release video.

Do you mean to say that you added a single speed, or that you run your pickup dynamically based on the robot’s speed? If dynamic, do you slow the rotation when driving in reverse?

Picking up an irregular object like the gear with solid wheels will greatly increase wear due to acceleration of the wheel as it passes between the teeth and sudden slowing when it makes contact with the next tooth. I have seen teams work around this problem (most particularly in 2015 picking up totes) by mounting the intake wheels on flexible arms which manage the compliance through moving the wheel axle, and often the motor/gearbox. Pneumatics or constant force (or at least prestressed) springs seem to be the tools of choice for this option, as the goal is to keep the contact force steady.

If anything, it is even easier to gear non-compliant wheels, since you don’t need to worry about stripping out the hex on them.

Compliant wheels certainly make things easier, since the spacing between the wheel and bottom plate is less critical, and you can get more “grip” out of it. But you can achieve a similar effect using a “floating” non-compliant wheel, or even just a rigid mechanism with a semi-compliant bottom plate.

As for gearing, I think 228 did 10:1 off a BAG with no issues. Fast enough to zap the gear off the ground on contact. We used AM 2" Blue Stealth wheels, evenetually covering them in 3M “gecko” grip tape for a bit of extra pull. If I had to do it again, I’d try out the green durometer.

Did anyone run a gear intake off their drivetrain this year?

This isn’t a good idea. There’s very few ways to do it that end up lighter than using a dedicated motor, and many more problems to solve with such an implementation (e.g. how do you drive backwards without ejecting the gear, how do you pick up a gear when you’re barely moving, etc)

Do you have any good pictures or models of how the mounted the top roller shaft? The compliance in it looks great and I am wondering how you maintained things like proper tension while keeping the whole roller nice and compliant. You mentioned looking at 2015 designs; is there some sort of spring loaded pivot up there?

Mistyped… they were PG27s, bought from AM once we settled on the design.
Raised and lowered via a KoP PG71 w/encoder.