View Single Post
  #74   Spotlight this post!  
Unread 21-07-2014, 16:07
JTN's Avatar
JTN JTN is offline
Registered User
AKA: John Taylor Novak
FRC #0016 (Bomb Squad)
Team Role: College Student
 
Join Date: Aug 2009
Rookie Year: 2002
Location: MIT
Posts: 82
JTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond reputeJTN has a reputation beyond repute
Re: Baxter Bomb Squad 2014 ~ Nighthawk

Quote:
Originally Posted by Bryce Paputa View Post
Why did you use 6 inch wheels over 4 inch ones? As far as I can tell, I think that 4 inch wheels would make the entire assembly smaller and lighter while needing less gear reduction. Any reason why I'm wrong?

How are the grooves for the thrust bearing cut?
We have found 6" wheels to be more suitable because they have more tread touching the carpet (realistically) and therefore more traction in most scenarios. The grooves were cut using a simple ball end mill... pretty easy to figure out if you ask me.

Quote:
Originally Posted by Bryce2471 View Post
1. What's that pneumatic cylinder doing in your CAD render!? It really caught me off guard.
2. What is the experimental 3D printed part below your thrust bearing?
The pneumatic cylinder was used (as described above) to lock the wheels in place only during wheel calibration autonomous to avoid the need to use any sort of software to keep the wheels straight and move in a straight line. It is much easier to just not supply power to the rotating modules and let them remain physically straight than run a control loop to correct it, slowing us down and removing accuracy. We didn't implement this or further develop it because of the lack of any need in this game. The 3D printed part contains the grooves that the cylinder shaft deploys into.

Quote:
Originally Posted by Bryce2471 View Post
But it also sounds like they're fixing a software problem with hardware.
This is entirely wrong. We didn't even USE it this year and there was no problem with control. I'm not sure why you would think a team that has been using swerve for a decade wouldn't know how to go in a straight line, all that is necessary to achieve that is to push forward on the throttle.. As stated before, the main purpose was to ensure consistent calibration (which we only do about once per competition) and to make going in straight lines in autonomous easier due to the lack of reliance on a gyro that it would produce.

-John Taylor Novak

P.S. As of now the CAD models have not yet been released to the public but I can supply images of the model instead.
__________________
They say I can't use a URL or BB code, so I'll use this for my signature.

Last edited by JTN : 21-07-2014 at 16:11.