30-01-2014 20:25

ehfeinberg

Re: pic: FRC488 - Octocanum Drive Rendering

Could you please explain your logic for having the three omni wheels in the center of the frame if you are already using mecanum wheels?

30-01-2014 20:29

AllenGregoryIV

Re: pic: FRC488 - Octocanum Drive Rendering

This is pretty awesome, do you catapult perpendicular to your traction wheels and collect from both the front and back?

30-01-2014 20:35

z_beeblebrox

Re: pic: FRC488 - Octocanum Drive Rendering

Follower wheels for distance and speed measurement?

30-01-2014 20:40

Chris is me

Re: pic: FRC488 - Octocanum Drive Rendering

Unpowered follower wheels allow the robot to know its true position and orientation at all times, regardless of slip in the drivetrain.

Beautiful drive base, and nice catcher? Excited to see the rest of it.

30-01-2014 20:48

ehfeinberg

Re: pic: FRC488 - Octocanum Drive Rendering

Oh that makes sense. So the 2 550 motors are not attached to the outside omni wheels?

30-01-2014 20:57

Akash Rastogi

Re: pic: FRC488 - Octocanum Drive Rendering

Looks like those might run the intakes?

30-01-2014 21:03

AllenGregoryIV

Re: pic: FRC488 - Octocanum Drive Rendering

Those look like 4 775s to me but maybe those are 550s, and there is another VP up in the center that looks like it is powering a cho-cho double cam.

30-01-2014 22:45

TheMadCADer

Re: pic: FRC488 - Octocanum Drive Rendering

How long is the wheelbase for the traction wheels? Do you want to be able to turn on them, or is it intended to not be able to turn?

31-01-2014 00:53

Madison

Re: pic: FRC488 - Octocanum Drive Rendering

As others noted, we use the omniwheels as follow wheels to give us true on-field translation information and a gyro to track orientation. This makes our field-oriented drive work.

Yes, that's exactly it.

Raising and lowering each of the intake systems is handled by 2 775 motors. The middle mechanism is the over-center linkage for cocking and releasing the catapult. People with think it's derivative, but I don't care -- I've wanted to use something like that for ages and we had to abandon our cool Geneva drive last season.

The wheelbase is about 14"; it's quite short and thus, we can turn on them. In our past experience, we did not spend a lot of time on the traction wheels. They're used for brief moments of added oomph and to resist sideways forces.

31-01-2014 01:11

AlecMataloni

Re: pic: FRC488 - Octocanum Drive Rendering

This is exactly the robot I would build if I were still competing. Awesome work!

31-01-2014 01:15

AllenGregoryIV

Re: pic: FRC488 - Octocanum Drive Rendering

Can everyone post teasers that are like this, you are actually able to decode what a team is doing from it.

31-01-2014 02:35

Michael Corsetto

Re: pic: FRC488 - Octocanum Drive Rendering

Agreed, this robot looks like an incredible machine. Very elegant and low low low

-Mike

31-01-2014 11:56

Mark Sheridan

Re: pic: FRC488 - Octocanum Drive Rendering

Very cool. Where did you get those follower omni wheels from?

31-01-2014 12:23

XaulZan11

Re: pic: FRC488 - Octocanum Drive Rendering

Do you need both intake arms down to shoot or do you have enough clearance?

31-01-2014 12:52

Michael Corsetto

Re: pic: FRC488 - Octocanum Drive Rendering

It looks like since they're on motors, they could potentially have more than a "down" and "up" position to their rollers. Really nice.

-Mike

31-01-2014 13:54

Madison

Re: pic: FRC488 - Octocanum Drive Rendering

Of course, I dislike teasers tremendously. I'll post a rendering of the completed CAD model as soon as it's done. I don't like sharing work that isn't of a high-caliber.

They're 3" Tetrix omniwheels from FTC kits. The actual diameter is closer to 2.75", though.

We do need to lower them a bit, but not to their lowest extent. When lowered far enough for the ball to be catapulted cleanly, the arms do not extend beyond the ends of our bumpers.

01-02-2014 05:54

pwnageNick

Re: pic: FRC488 - Octocanum Drive Rendering

The 2.75" Double Roller Omni Wheels are also quite nice.

http://www.vexrobotics.com/276-1902.html

And if you don't like using the 1/8" square bore in them you can shove a 1/4" hex shaft through them. Some VEX teams have done it before with 1/4" hex standoffs (since that's a legal VRC part). You might be able to take it up to 3/8" hex if you machine it.

01-02-2014 08:46

gpetilli

Re: pic: FRC488 - Octocanum Drive Rendering

We are using the Vex dually as follower wheels. We even use the Vex encoders on the 1/8" shaft. We made 3d printed forks to hold it all together.