Intake Motors...
 

As of right now, my team is using Andymark PG71 gear motors, mated to the AM-0914. We are running into difficulties with the speed the motors are running on our intake arms. These Andymark Motors are not running at the speed we need to be able to suck in the totes properly. A weight is an issue on our robot, but we need the speed.
I was wondering if anyone had any recommendations on anyway or any other motors with a gear box that will help?

What gear ratio are you running your intake wheels at? 5 to 1, etc......???

Maybe a BAG motor with a gearbox from VEX? I appreciate any ideas and references to a specific set up that will work!

Re: Intake Motors...
 

A BAG motor with a VersaPlanetary Gearbox with a one of the following ratios 5:1(2800RPM Free), 7:1(2000RPM Free), 9:1(1555RPM Free), 10:1(1400RPM Free)

We are running our 4 7/8 Banebots wheels with a 10:1 BAG on our bot intake.

Re: Intake Motors...
 

The PG27 will run almost three times as fast as the PG71. The gearbox is available separately, and will be a direct replacement, no resizing of other components should be needed.

Re: Intake Motors...
 

I don't know why you guys are geared so fast. We have a BAG geared 35:1 on 4" wheels and it grabs the totes VERY quickly - less than a second from contact to in place. As in our intake slams the box into our frame before we can react. Plenty fast. If you go with a BAG, you definitely want at least this much reduction. In testing we used 15:1 and the intake was so fast that most of our traction materials couldn't grab the tote without burning out.

Edit: Didn't realize you were using the PG71 - which is already geared down 71:1 as the name would suggest. A PG27 is both faster and lighter, and would make your intake 3x as fast (with 3x less torque).

Re: Intake Motors...
 

I have seen a wide range of ratios for intake wheels for this year. The amount of compression and wheel diameter will also factor in. From Andymark, have you tried the PG27 (27:1)? If you were to purchase items now, I'd recommend the VersaPlanetary due to it's flexibility in ratios, motors, and mounting. The weight looks to be a wash between the 2 options. We have a mix of ratios on hand for the VersaPlanetary too. I think we have the PG27, but would need to check. Let us know if we can help. :D
Nate

Re: Intake Motors...
 

Also worth noting (edit: Silver did), as I'm personally looking at options to integrate an active intake for swap in at next competition...

Shouldn't the discussion shouldn't be more along the lines of linear speed?
A faster RPM on a smaller BB wheel or a slower RPM on a larger BB wheel would likely have similar results (not accounting for rotating mass and wear effects).

So if a given team is running their intake rollers at X RPM, I think noting the type of wheel and diameter would be pertinent.

Re: Intake Motors...
 

We prototyped intake wheels and came to the conclusion that the max linear speed we'd need to pull in the tote (assuming no slip) was around 5 ft/s. To achieve this we had selected 2-7/8" banebots wheels paired to VersaPlanetary geared to 30:1 and powered by a bag motor. We would then be able to slow down the intake from there if needed. I want to note that currently our bot doesn't make use of intake wheels so this is where our data ends. :(

Re: Intake Motors...
 

We're using RS-550 motors on Banebots P60 64:1 planetaries. The wheels are home-grown and 4" in diameter. This setup is working well for us.

Re: Intake Motors...
 

How do you prevent the motors from stalling as the intake completes?

Re: Intake Motors...
 

We have window motors geared up through belt and sprocket about 1:2 with bane bots 4 7/8" wheels on the end.
Seems to be working great so far. No issues with stalling or going to fast/slow

Re: Intake Motors...
 

To save some money, we maintained our PG71 setup by replacing the RS775s with 9015 motors (am-0912), providing us with a 71:1 ratio (225RPM Free).

We use 4 7/8" BaneBots wheels too, giving us a decent ~4.75 ft/s tangential speed on the intake. If you choose to pair your existing PG71s with 9015 motors, be sure to order the necessary hardware kit.

Re: Intake Motors...
 

We're using 50:1 Versaplentary's with bag motors & 3 7/8" orange banebots wheels. They work pretty well for us, we may try some 4" colsons though as the banebots wheels are getting chewed up quickly.

Re: Intake Motors...
 

We're using BAG motors with a 100:1 VersaPlanetary gearbox running 4" colsons. While it intakes totes a little slower than some of the other designs out there we found that the higher ratio gives us enough torque to allow for some misalignment on the totes and still reliably intake them.

Re: Intake Motors...
 

A limit switch on a digital input tells the control system when a tote is within its last inch of travel.

Re: Intake Motors...
 

Do you have a picture of that you could post? So many rookie teams ask for advice how to mount limit switches. It would make a good reference link. Thx.

Re: Intake Motors...
 

If it wasn't for that big ol' bag on the robot...
Now I have a reason to get that switch onto the practice robot.

Our frame serves as the mechanical stop for the totes, extending the life of the switch to beyond one cycle. :)

Re: Intake Motors...
 

Yeah, that's what I'm talkin' about :)

Re: Intake Motors...
 

Two other techniques we considered for our ball pickup last year are:

1. Make the frictional force low enough that when the game piece is fully in place, the wheel slips. Problems with this method include possibly reduced intake force and rapid wear on your rollers.
2. Monitor the current draw on the motor and cut it off quickly when it spikes. This used to require custom current sensors, which we had purchased from pololu, but now they're built into the power distribution panel.

Last year we used our solution number one, as the balls were compliant and not much force was needed to pull them in; it may not be a good solution this year.

Re: Intake Motors...
 

http://www.andymark.com/product-p/am-0915a.htm

^^^^ Is this what you are talking about because i believe I am going to place an order for these right now..

Re: Intake Motors...
 

There are options. If you just want the gearbox, gearbox with 500 series motor, or gearbox with RS775 series motor. Please ensure the motor you use is one that is allowed from R18 in the manual. There are also PG series parts that may be of interest as well.
Nate

Re: Intake Motors...
 

I swear to you, Sarath, I came here to post this, read your post and was about to send it to you, like 'Hey! Someone else did it our way too!" ...Whoops.

Something we did notice during driver's practice is that with our wheels running, simply touching a tote from with the outside of the intake (read: we're not at -all- lined up to grab that tote, off by a huge angle) breaks up the cluster of the Landfill pretty quickly and gets the tote lined up for us to better close in on it. So, while our actual tote intake is a bit slower, we can get individual totes lined up for capture with very little effort.

Re: Intake Motors...
 

Depending on the game, a good rule of thumb I like to go by is to always gear your intake a bit faster than the speed you'll likely be approaching the game piece at. For example, in 2014, many teams approached the balls on the ground pretty quickly, and if their intake was slower than their drive speed they'd end up pushing the ball around with them as they drove. Teams who geared their intakes faster than the speed they were approaching the balls at could drive up to one and have it in their possession almost instantly.

This year most teams aren't going to be approaching totes and bins head on at high speeds (let's hope they don't, at least), so while intakes should be fast, they won't have to be as fast as they have been in previous years.

Re: Intake Motors...
 

Yes, that's the PG27 with the motor and the rear axle extension for an encoder. That extension may be a problem if you currently have short clearance behind the motor, but it'll save a swap out step if that's OK. If you just want the PG27 gear box for $14 less, it's here:

http://www.andymark.com/product-p/am-2937.htm