pic: Begin Week 3 Prototype



This is the state of our prototype as we begin week 3 of the 2015 build season. The current estimated speed is 14 ft/s. We are staying with the use of omni wheels and we are in the process of programming slide drive.

UPDATE: We switched from slide drive to Mecanum.

14fps seems mighty fast.
In a game with such limited real estate, accelerating up to and down from that speed might be difficult. You might consider, after testing, switching gear ratios and go for torque over speed.

What’s the slide wheel radius, and what’s the total speed reduction from motor to wheel for the slide wheel?

We just switched from slide to Mechanum, considering that speed isn’t a big priority.

Yeah, that’s why we switched from slide to Mecanum becuse speed isn’t big this year.

well im going to have to disagree with you on that speed is everything this year with the new format for playoffs and ranking you have to be faster then your opponents

I’ll see your “faster then your opponents” and challenge with
“What greater opponent is there then time in this years game?”

How did the 4 wheel Omni with the frame in the long orientation handle?

I’ve never used mecs so correct me if I’m wrong but I believe mec drives are generally geared to a lower them “normal” speed because of the amount of force needed to strafe.

I asked in your last picture as well what the estimated speed was because it seemed really high. Think about it this way, in 2013 teams that were successful single speed cyclers were geared in the 13 or 14 fps area. They were loading at the human player station then bolting across the field to the pyramid which automatically lined them up for their shot in a rather wide goal. Not a terrible amount of accurate needed seeing as you could auto aim your robot by hitting the pyramid. In this game at any given time you have half that distance to travel, and you don’t need to fly across the field for any reason. For 2015, I’d say accuracy in lining up crates/stacks > raw speed.

Tl;dr a high drive speed doesn’t necessarily mean you’re going to stack crates faster. And I’m pretty sure you need a bigger ratio for mecs but I could be wrong.

On another note, the business end of the robot is looking good.

We ran 6" mecanum on 9:1 reduction for years and were quite happy with it. Is that “lower than normal”?

The forward speed of mecanum will be just as fast (or VERY close to as fast) as a normal tank drive. The OD of the wheel is not any smaller.

Very cool. Good job.

who716:

However, speed for manipulating and stacking totes is more important for the speed of the actual drive system this year. This year robots aren’t gooing across the field to drop a game element somewhere.

Efficiency seems more important than being fast. It doesn’t matter if you can cross the field and create a stack of 6 in 2 seconds if it only works 50% of the time. Being able to do one task as efficiently as possible is the key to winning.

Maybe you meant consistency when you were talking about being able to do it 50% of the time…but yeah, I agree, efficiency is also very important (which could possibly be achieved by drivetrain speed, just one aspect however).

I actually meant both.

Just would like to point out that, while all that really matters is your ‘speed’ of scoring, that doesn’t necessarily mean the ‘linear speed’ of your drive train.

254?

Yes, 254.

Exactly.