pic: Offseason Shooter CAD Project

[Cothron Theiss]

Originally Posted by Sperkowsky

I used the Belt/Chain Tool to actually model the belt but, I first did a sketch of everything.

This is probably more helpful for your drive rails than this shooter, but you can also set make the belt feature itself be a driving distance, meaning that you can leave something like sliding bearing blocks undefined in your assembly, and let the exact length of the belt feature definite the placement of your front and back axles/wheels/bearing blocks. But if you want to build your shooter model so that it's easy to change in the future, you can use this same belt feature and have the placement of your bearing holes and lightening patterns driven by the length of your belt.

Just some interesting things i found when working with the new and improved belt feature in SW 2016.

[JesseK]

What holds the ball away from the wheels while the shooter wheels spin up?

edit - I see your comment about the hex shafts, but what about their placement gives you reasonable confidence they alone are enough?

[Sperkowsky]

Originally Posted by JesseK

What holds the ball away from the wheels while the shooter wheels spin up?

edit - I see your comment about the hex shafts, but what about their placement gives you reasonable confidence they alone are enough?

In all reality it does not completely. I am not worried about the ball hitting the wheels as I can always ramp up the shooter motors in reverse for a bit longer but I do think it will hold the ball adequately enough. I am not adverse however to be a better securing system I am just trying to figure out the least obtrusive way to implement it without adding more unneeded complexity or changing the form factor dramatically.

[Ether]

Originally Posted by Sperkowsky

..the free speed after reduction ... is around 9005 RPM. JVN's Calculator it says in reality it will be about 8990.4 RPM

I was asking about the expected operating speed, not the free speed... or are you saying you expect to operate the shooter with 100% voltage (with no headroom for closed-loop control) ?

[Sperkowsky]

Originally Posted by Ether

I was asking about the expected operating speed, not the free speed... or are you saying you expect to operate the shooter with 100% voltage (with no headroom for closed-loop control) ?

Well, we probably will have some sort of closed loop control but I am not to sure at the moment. This year we ran our shooter motors at 80% so I am going to guess if we build this shooter we will do the same. So, I am going to guess the shooter motors would run at about 7000 RPM.

[Ether]

Does anyone have a link to a trustworthy number for the rotational moment of inertia of the CIM rotor?

It might be instructive to do some trade-off computations comparing the increase in rotor angular momentum with increasing rotor speed versus the drop-off of CIM torque with increasing rotor speed.

[Sperkowsky]

I worked on a better way to mount the tilt plates and went with the l bracket method. I left out fasteners due to the fact that this will be cut by hand most likely by a brand new member. I also gave up on Lightening holes as there's not much surface area left but the good news is that means if we want it can be done with our manual mill. I am going to work on finishing this robot up in the next two ish weeks so I'll probably have a few more threads like this. The help is really too good to pass up and it's offseason so everyone is winning. Thanks

http://i.imgur.com/yLaPG0F