Hello, my team is looking into moving our intake this year with a motor instead of pneumatics and I was curious how every other team does it? We are looking into making it fairly quick aswell. Any tips or recommendations on steps to do would be greatly appreciated, thank you!
I recommend double double, animal style, and you gotta get the animal style fries. Shakes are pretty good as well. I’d watch your intake, though, since too much and you’ll exceed the frame perimeter.
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I should have seen this coming 
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Is your intake a 4-bar or just a simple slapdown intake?
Generally, mount the intake to a dead axle, and then just try to make sure there is as little slop in the chain as possible.
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Some pictures or at least a description^ of the intake and any major constraints around it (i.e. shooter in the way) is needed to give some good advice. What may be a sound option for one architecture is likely to be woefully inadequate for another.
^(where motors/shafts are, type of intake (4-bar, slider), general mass of system, etc)
If you are having trouble sharing for some reason or another start looking through robot cad/pictures or RI3D. 2022 may be good for some past designs, RI3D for this year specifically.
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Tonight I’ll get some pictures of what we have currently, we are using a 4-bar style intake and have it mounted to a shaft already. ATM our plan is to use a neo on a maxplanetary but I’m trying to figure out how to connect it.
@suPURDUEperAndy Did you do a white paper or video series on this topic?
If you have the freedom I would swap your shaft over to a MAX Spline, or WCP Spline XL. From here I would recommend using a belt/chain connection from your motor to shaft.
I would then bolt that sprocket/pulley directly to your 4-bar plates to reduce slop.
Another solution that has worked really well for me and us at Cranberry Alarm Ri3D was the gear connection to the hex axle. My team will be doing something similar but switching over to the REV MAX Spline, and so far are very happy with the results. One worry with this is its point loading of gear teeth during impact, which is why its important to use steel gears or just go with belt/chain.
Check out this video for a quick demo:
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If you want to see a 4 bar intake design you can look at 1678’s 2022 robot. Their CAD is available on their website. Nick Arestad also has a good series on YouTube where he CADs an intake.
This year you may be able to make do with just a single jointed arm, in which case some of the resources here may be helpful: 180:1 (max Planetary 60:1 + belt 3:1) - #5 by Max_Morehead (though you shouldn’t have to make it so heavy duty). The most applicable recommendation for a small arm is to run chain from the gearbox to a sprocket bolted to the arm.
For controls, ideally you’ll want a limit switch on one or both of the ends of travel, plus an encoder, or an absolute encoder on the output shaft of the arm.
I would look into putting some mechanical seperation in-between the max planetary and the driven link (crank) of the 4-bar. Planetary gearboxes are nice and compact but those little gear teeth don’t handle shock loading well, are hard to inspect, and somewhat hard to have enough spares of.
The usual solution to this is a chain reduction (or 1:1) between the 4-bar and gearbox (chains spread the load better than a set of external spur gears)
Assuming a classic FRC 4-bar. You will also want to make sure you are driving both sides of the 4-bar mechanism synchronously (left and right cranks) . This is usually done with a shaft across the robot, even if using multiple motors.
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Didn’t link to op reply nor did my second try 
This is the early work up our team is using this year using a modified Cranberry style. Second pic is of a support bar for impacts using tpu joints. The intake tests have this moving very smooth and fast with minimal tuning
Edit: tried uploading an intake movement video but it isn’t supported
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Edit: I misunderstood the question at hand, sorry
A few tips, mostly stemming from failures throughout the years.
Try to make your intake auto-collapsing. In other words, if you run full speed into a wall or another robot with your intake deployed, you want it to fold back in rather than break. Pneumatics can actually be good for this if the load path doesn’t cause the cylinder rod to bend, but often times a motor can accomplish largely the same thing with a current limit.
As with most rotary mechanisms with a decent amount of inertia, make the last stage of the arm/intake rotation a chain. This has a number of advantages over gears:
- The load from a impact/impulse is spread out over a larger total surface area than gear teeth, which have a surprisingly small contact surface. Sheared gear teeth are always a bad sight to see.
- Chains also have some amount of stretch, lowering the impulse (and thus, force) the rest of the reduction will see.
- Often the failure point becomes the chain itself rather than the gear, which is typically easier to swap out in an emergency situation.
- You can easily tension a chain or design the C-C to have little-to-no backlash.
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One thing that’s not getting said that I think new FRC designers often miss is how to attach your chain and sprocket to your mechanism.
And the answer is to bolt it.
You’ll notice almost all the sprockets from FRC manufacturers have hole patterns radiating out from the center:
These are to bolt the sprocket to the thing you want to spin, rather than transfer the torque using a hex bore.
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We had a student create a little vdeo for the FIN video contest one year. It doesnt go into any deep implementation, but highlights some ways to avoid pneumatics.
Hi all, we got some testing and it works super super good!
Thank you all for your help!
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