Log in

View Full Version : pic: FRC488 - Octocanum Drive Rendering

Madison
30-01-2014, 20:03
[cdm-description=photo]39420[/cdm-description]
ehfeinberg
30-01-2014, 20:25
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?
AllenGregoryIV
30-01-2014, 20:29
This is pretty awesome, do you catapult perpendicular to your traction wheels and collect from both the front and back?
z_beeblebrox
30-01-2014, 20:35
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?

Follower wheels for distance and speed measurement?
Chris is me
30-01-2014, 20:40
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?

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.
ehfeinberg
30-01-2014, 20:48
Unpowered follower wheels allow the robot to know its true position and orientation at all times, regardless of slip in the drivetrain.

Oh that makes sense. So the 2 550 motors are not attached to the outside omni wheels?
Akash Rastogi
30-01-2014, 20:57
Oh that makes sense. So the 2 550 motors are not attached to the outside omni wheels?

Looks like those might run the intakes?
AllenGregoryIV
30-01-2014, 21:03
Looks like those might run the intakes?

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.
TheMadCADer
30-01-2014, 22:45
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?
Madison
31-01-2014, 00:53
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?

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.

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

Yes, that's exactly it.

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.

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.

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?

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.
AlecMataloni
31-01-2014, 01:11
This is exactly the robot I would build if I were still competing. Awesome work!
AllenGregoryIV
31-01-2014, 01:15
Can everyone post teasers that are like this, you are actually able to decode what a team is doing from it.
Michael Corsetto
31-01-2014, 02:35
Can everyone post teasers that are like this, you are actually able to decode what a team is doing from it.

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

-Mike
Mark Sheridan
31-01-2014, 11:56
Very cool. Where did you get those follower omni wheels from?
XaulZan11
31-01-2014, 12:23
Do you need both intake arms down to shoot or do you have enough clearance?
Michael Corsetto
31-01-2014, 12:52
Do you need both intake arms down to shoot or do you have enough clearance?

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
Madison
31-01-2014, 13:54
Can everyone post teasers that are like this, you are actually able to decode what a team is doing from it.

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.

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

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

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

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.
pwnageNick
01-02-2014, 05:54
They're 3" Tetrix omniwheels from FTC kits. The actual diameter is closer to 2.75", though.
Very cool. Where did you get those follower omni wheels from?

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.
gpetilli
01-02-2014, 08:46
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.

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.