New AndyMark PG motors


No clue if these will be FRC legal for the next competition (though I see no reason not to have them be legal), but these might be useful, if a little expensive. (They do beat a 3 stage VP on price, though nearly everyone already has those parts on hand)

Thoughts?

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Ok

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“Ventilators”?

ohno

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If 6.4 isn’t enough for you, you can always try 11! I agree with @troy_dietz, I’m assuming these are used for ventilators such as the MIT e-vent.

I initially thought that, but the PG188 is what the E-Vent design calls for, and AndyMark isn’t offering a huge quantity discount like they are with the PG188 and 192:1 NeverRest Sport. I don’t know what the whole design looks like though, so maybe this also accounts for a reduction that happens later down the line in the design?

They could presumably be offering these as they can be made to work in a “ventilator” as stock of the appropriate reduction for common designs is depleted.

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Honestly, most of the cases that I can think of where you want to move a mechanism this slowly would also be high load applications. As an example: thinking about 2019’s endgame HAB3 climb, many teams had some sort of arm off the front of their robot that would grab the top of the hab and pull up the front of the robot. That could be accomplished with 90-ish degrees of rotation (so ~3 seconds with this 977:1 reduction), but the load that you are lifting is quite large and the lever arm is also quite large.

These motors are not ideal for these type of applications for the following reasons:

  • The PG motor is not really that strong. so even though the torque is decent with this 977:1, it does not compare to a similarly geared MiniCIM or NEO or 775Pro.

  • Actuating a high load arm through a hex joint is probably not the best design practice given the high loading at such a small diameter. It is usually better to accomplish the final reduction with a large diameter gear or sprocket that can be directly attached to the arm so that the load is carried by a bolted joint at a large diameter from the pivot.

So, you would want to limit this gearmotor to lower load applications and honestly, I can’t think of any that would require motion this slow.

Having recently diassembled some of our older PG188s and PG71s it is easy to see how you could just keep stacking the stages and just cut the extrusion that forms the outer case to longer lengths. So, there are no new parts here (just re-configuration of existing parts). So it is an easy configuration to offer. Who knows, maybe applications will come up where this will be the prefect part for the job. But, I think those cases will be rare.

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It sounds like these would work well for adjusting a shooting hood, or directing a lightweight turret. It has a built in encoder, so it should work well to make a heavy duty “servo”.

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All; for some clarity - we made these available specifically for customers who are building breathing assistance devices. It utilizes the same am-3108 and am-3109 motors as the PG series, so assuming that motor would be legal for future seasons; I’d imagine this configuration would be considered FRC legal too.

It’s important to note that these higher reduction options can break the gearbox when stalled, even with the low-wattage motor it’s paired with. This is not how they are operated in these breathing assistance devices. There’s a lot of torque there!

-Nick

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At 6.4 and 11 RPM free speeds respectively, these motors are too slow even for direct-driving turrets and adjustable hoods. They’d need to be geared up, at which point you’re just unnecessarily sacrificing efficiency. Plus, both turrets and adjustable hoods have built-in chain/belt reductions to position the motor to the side instead of needing to be concentric with the axis of rotation.

I really don’t see any use for these in FRC other than maybe pulling a pin or something, which could also be done by a servo.

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How about extending an intake system for example? (For teams that prefer to not use pneumatics)

First of all, I still think that’s too fast. Let’s say it’s 120° between stowed and deployed, and you want to cover that in half a second. That’s 40 RPM, or ~4x faster than the free speed of the faster option.

And also, you wouldn’t want to direct drive the intake rotation off the planetary because planetary gearboxes also are sensitive to shock loads. Not to mention that at that high torque you’ll probably strip/twizzler the hex axle if the intake takes an impact. So you’d want some kind of chain/belt reduction between the intake and the planetary, at which point you can add reduction there and get away with a much smaller (and lighter and more efficient) gearbox.

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