TechHOUNDS Wheeled-Shooter Prototype 2014

[cnepo]

Here's a video of our first Wheeled-Shooter Prototype for this year's game. This is the kind of work that gets accomplished when school's not in the way!

Specs:
- 8" FIRST Wheels (x4)
- CIM Motors (x2)
- Mini-CIM Motors (x2)
- PVC Guide Rails

Performance:
- 16 feet away from "Goal"
- Hits ~7'-8' into the "Goal"

[blaze8902]

That looks pretty good. That top-spin will come in handy too.

This post from #1660
Motion of Projectile App

and this one from Ether
Parabola Equations

may come in handy during your prototyping.

One thing my team has been considering is the value/plausibility of allowing for two separate arcs, one for truss shooting and another for High Goal shooting. With truss shots, catching would be easier if you were to "lob" it (a more angular path) and for High Goal, a more "linear" path is probably better. So if you can shoot the ball two different ways, it might work out a little better.

[MrRiedemanJACC]

Very Nice! So I'm assuming you had a Cim and Minicim on each side? Were the 2 pairs of wheels the same speed or did you step up the second one?

[cnepo]

Originally Posted by MrRiedemanJACC

Very Nice! So I'm assuming you had a Cim and Minicim on each side? Were the 2 pairs of wheels the same speed or did you step up the second one?

Yup. We are using a CIM and Mini-CIM combination where the first set of wheels moves at a slower speed and the front set is a higher speed, following the same concept of a lot of shooters from last year's game.

[Ether]

Originally Posted by cnepo

Here's a video of our first Wheeled-Shooter Prototype for this year's game.

Could you post some close-up photos* of the ball after it's been through the wringer a few times? There's a lot of speculation about damage to the fabric.


* preferably with a camera that has a macro setting so the focus is sharp

[cnepo]

Originally Posted by Ether

Could you post some close-up photos* of the ball after it's been through the wringer a few times? There's a lot of speculation about damage to the fabric.


* preferably with a camera that has a macro setting so the focus is sharp

Here's a picture of our ball after close to 60 shots taken. The tears are from testing the compression on the ball, but nothing more than scuff marks once we got everything dialed in. We have continued to test and have not been able to create any more tears into the fabric.
http://i.imgur.com/5frvmdL.jpg

[Ether]

Originally Posted by cnepo

The tears are from testing the compression on the ball...

Could you clarify what you mean by "testing the compression" ?

[blaze8902]

I'm also interested in the data from your compression testing. If you'd be willing to share it, I'm sure many people would appreciate it. Potential fabric damage tests would be great as well, as Ether asked.

Oh, and a comment about the wheels you're using: Have you considered using pneumatic tires? We saw many of them last year for Frisbee launchers, and I think they might work well for your case. Both the wheel and the ball will compress, and it should mesh well together, and the rubber tire material should work well with the ball fabric also. I think teams ran into some balancing issues, but they worked well in the end, generally. Cheng Shin 200x50s is what we prototyped with last year.

[CheerlessBear]

If you where to use pneumatic wheels it might cause too much friction and tear the ball. Last year our robots pneumatic wheel in the shooter tore up frisbees so i would be concerned about using them this year.

[OzzyArmas]

THANK YOU THANK YOU THANK YOU!!!!!

We are a rookie team, we don't have enough parts to prototype and I kept insisting a wheel shooter would work but doubt continued in the team because of all those catapults. But no one had tested the wheels until now so.... THANK YOU!!!!

Our Robot design is now definite :3

[Aroki]

Originally Posted by OzzyArmas

THANK YOU THANK YOU THANK YOU!!!!!

We are a rookie team, we don't have enough parts to prototype and I kept insisting a wheel shooter would work but doubt continued in the team because of all those catapults. But no one had tested the wheels until now so.... THANK YOU!!!!

Our Robot design is now definite :3

The challenge with a wheel shooter will be space, the OP's prototype is pretty much the size of the ball. If you wanted to be able to pick up, carry and chose when to fire you'd need to fit a separate pickup/carrying and firing space.

[Abhishek R]

Originally Posted by Aroki

The challenge with a wheel shooter will be space, the OP's prototype is pretty much the size of the ball. If you wanted to be able to pick up, carry and chose when to fire you'd need to fit a separate pickup/carrying and firing space.

Not necessarily. The shooter can be your carrying space. Many teams fed discs in 2013 through their shooter (if I remember correctly 868 was one of those).

[Aroki]

Originally Posted by Abhishek R

Not necessarily. The shooter can be your carrying space. Many teams fed discs in 2013 through their shooter (if I remember correctly 868 was one of those).

Yeah but you can't have it stored in contact with the shooter wheels so it has time to speed up before you shoot. I'm in no way saying it's impossible, just that it may be difficult to figure out.

[OzzyArmas]

Originally Posted by Aroki

Yeah but you can't have it stored in contact with the shooter wheels so it has time to speed up before you shoot. I'm in no way saying it's impossible, just that it may be difficult to figure out.

We are taking advantage of the extra 20" in each direction. The front is used to lower a pic up much like JVN and all those 3 day robots, the back will hold a box that opens 20" back so we can hold the ball there and use that space for catching the ball from other robots. The Shooter is much like those from 2012 with two wheels at the top and two at the bottom.

[efoote868]

Originally Posted by Abhishek R

Not necessarily. The shooter can be your carrying space. Many teams fed discs in 2013 through their shooter (if I remember correctly 868 was one of those).

Our shooter was underneath the hopper, so while it might looked like we were feeding into our shooter, we weren't