Hi, my team is wondering how does the actuated intake work.
Actuated intakes tend to use a ratchet, so when you spin one way, they spin in, but spinning the other way catches the ratchet and opens the intakes. The most basic version will have the ratchet mounted to the moving piece of metal. Spinning one way lets the ratchet slip but the other way catches and opens the metal.
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Also, for our intakes, we have them geared 1:5 so they have more strength going out. You might want to consider that. (the ratio is only for the ratchet so the intakes still spin at 200rpm)
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Would a 2:1 ratio work?
if your banding is really weak then perhaps, although you can’t get a 1:2 ratio with gears and I don’t think using chain on this crucial part of the robot is such a great idea. If you don’t have space for a 1:5 then 1:3 might be viable. do note I’ve never built these though so I may be underestimating how much torque the intake actuators need to open the intakes.
If you want to change the gearing for the actuation part, keep in mind that if you have it going faster than 1:5, then you will have to slow down the motor speed when opening. 1:5 already goes really fast when opening, and on my old robot (1:1), I had to run the motor at 20% speed.
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What I run:
600 RPM
2:1 gear ratio (Using sprockets)
2 inch intake rollers
1 rubber band that is barely stretched
Is what I have on my ratchet intakes. They burn out in about 5 mins so kinda annoying to use while practicing but if you have them on quick swap it shouldn’t be a problem.
You mostly have to optimize the ratchet. Current it barely moves when I spin the intakes for intaking and no slippage while flipping out.
My recommendation:
200 rpm
3:1 (With sprockets)
4 inch flex wheel
less optimized ratchet or better
This would have the same speed at intaking as mine but would have more leniency in the ratchet quality.
Also I want to explain why you should use chain:
- Lower friction
- Doesn’t snap as long as it’s not to tight and isn’t bending (Different sprocket heights)
- Your able to put 2 spots of bracing with metal on each side of the sprocket. This is the most important by far since this is the biggest friction issue. This is because the intake arm wobbles more with only one bearing and that applies more pressure to the axle since it acts like a lever. (HS doesn’t fix this)
Gears done right can still do all these things but it can be more complex with your bracing and a lot heavier.
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pretty sure a 1:3 with gears will be much more compact, lighter, and more robust that sprockets and chain.
not to say it’s necessarily wrong to use chain, but it just seems like the inferior option to me.
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You would use a 7:3 which would need idler gears and also need to have an absurd amount of room to fit the 84 tooth gear.
Chain would require a 18 to 6 tooth and some chain which takes up less space and is lighter.
I would like to see what your intakes look like. Here are mine:
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or just use a 12t gear meshing with a 36t gear? that’s a 1:3 ratio there that’s only 4 holes long and 3 holes wide. which is smaller than chain, probably lighter, and has no risk of breaking.
Do you have the motors on the intake arms?
I’m not using actuating intakes, just talking theoretically.
also your picture looks like the actual actuating mechanism is a 1:1 ratio, since you have your ratchet direct driven. your chain ratio is only effecting your intake roller ratio, not the actual actuating ratio.
Yea, It’s a 600 rpm ratchet with a 2:1 ratio to the intake rollers. Running an external ratio from the motor to the ratchet it unnecessary since 200 rpm can easily ratchet an intake. (Even A bit too fast) Then I optimized the arm to be as light as possible so I could run a 600 rpm directly to the ratchet.
really, a 600 rpm motor can direct drive the intake actuation? is your banding like super light or something? I wouldn’t have expected that to work, but it’s cool that it does for you.
Well yeah, from the picture the banding is light enough that the intakes probably aren’t able to descore from a tighter goal. If all the goals at a comp are loose, you’re good!
The downside to a 1:1 ratchet is that you’ll have to reduce the speed to like 20%, and you’ll have almost no strength.
and that whatever resistance is present in the ratchet will be increased by using a lower torque input on the ratchet. I have not built an actuated intake, but IMO you should always gear the ratchet in this scenario because it gives more flexibility (with rubber bands etc.) and lowers the resistance on your intake motor (allowing you to make better use of the motor’s power)
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Yeah, this is important for having enough torque.
For example, on our original ratcheted intakes, the ratchet had a ratio of 3:1, while the intakes themselves had a ratio of 3:7.
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