Hello Forum!
I have been scouring ChiefDelphi and other various resources, and I have seen much talk about using turrets as a method of aligning the shooting mechanism. However, I have not been able to figure out how one would power the turret to turn (and at such precise increments).
I’ve been specifically looking at team 1717’s and team 1323’s design. Can somebody delineate the confusion of the turret?
I’m assuming they both utilize a lazy susan of some sort.
Disclaimer: I haven’t looked at 1717 and 1323’s turrets.
A motor and a belt going around what you plan to turn is enough to turn it.
You can math out how much it will turn in a certain period and then hard code any specific increment into the code, such that each button push moves it X degrees. It can also be done with shaft encoders and gyros, both which with some math can tell you the exact same thing, with some precision.
Here is a nice photo of FRC25 from 2006, it should give you some ideas.
We had a turret for Lunacy - essentially, we took a lazy susan and riveted some belting around the outside. That belting went out to a small sprocket on a slow turning motor. Hook up an encoder to that motor, and you have some great control - due to the size difference (12" outer diameter for the lazy susan, 1 inch diameter for the motor sprocket), it took a ton of turns of the motor to get the turret through its entire arc, which allows you a lot of precision.
In 2009, 1726 made a turret out of a swamp cooler pulley. Here’s the end result. We cut the spokes out of the middle and used the remaining bit of them to mount the turret, then attached bearings in strategic locations around the belt. There was slight wearing from the pulley-on-bearing action, but it was minimal.
Could you reference the designs you are talking about? (links I mean)
We built an award winning & published turret system in 2006.
http://www.chiefdelphi.com/media/photos/33185
http://www.chiefdelphi.com/media/photos/25671
It was a custom lazy susan application with two plates. One on top of the other & a LOT of small plastic ball bearings riding in a grooved track between the two.
A motor driven wheel (shown below the plate on the left of the image) drove the top wheel & allowed everything on top of that including the motor driven shooter wheel to turn with ~340 degrees of motion.
The only reason we couldn’t turn a full 360 degrees or beyond is because we had cables running up to the shooter motor we couldn’t safely route around the turret as it spun.
The ~340 degrees was plenty of a range of motion we desired though in this instance.
If you can get a copy of the FIRST Robots: Behind the Design book from 2006, it is featured in there with a more in depth explanation.
Nice work!