Hi y’all, our team is going with a climber with two rack and pinion arms on both sides. We are worried that we may not be able to hold our robot up at the end of the match. Is there some calculator to calculate this or is it obvious that it will or will not hold? Thank you!
PS: our gear ratio for climbing is 100:1, and we are using neos.
I don’t think that there is a calculator to look into this. However, two arms with a 100:1 reduction would most probably hold or unwind very slowly. We have two telescopes with a 25:1 ratio with Falcons with a 1.5-inch spool and they seemed to be sufficient to hold the robot in break mode for more than 15 seconds before it touched the ground. But the best way is to test it.
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I want to say 2 NEOs at 100:1 should be able to hold for at least 5 seconds before descending but there is no way of knowing for sure without knowing more specifics about the robot and climb.
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This doesn’t tell the full story without knowing the pitch diameter of the pinion.
Recalc is a pretty good resource for this.
Here is an example set up for what you described assuming a very large 4 inch pinion:
Looks like it should work, but depending on the tooth size of your rack and pinion I would potentially be worried about tooth load. Chains or ropes are better for applications like this because they don’t concentrate the load on a single tooth.
Edit to add on: I don’t know of any calculators that calculate brake force of a shorted motor although it probably is possible to calculate. Normally motors make peak torque at stall and it goes down from there, but braking torque is 0 when a motor isn’t spinning and goes up with RPM.
It isn’t immediately obvious if brake mode alone is enough without more details such as how high you actually climb, but at 100:1 the braking force should definitely be significant.
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