Drive system vs. ground pickup

Two speed shift on the fly drive system (5fps and 15fps), powered by 4 small CIMs and no ground pickup

Single speed drive system powered by 2 small CIMs (geared for 5fps) but with ground pickup

(in both situations the robot would have a very capable shooter and basket)

Which would you chose and why?

I’d have to go with ground pickup. Shifting is nice of course but given the options ground pickup seems to be a stronger advantage. Before the scrimmages I may have chosen the other one, but seeing so many loose balls on the field tips the scales IMO.

A basket is great for loading when on defense if you have a good human, but on offense you’d have to return to your side every time you run out of poof balls. The ground pickup, on the other hand, can be done on the far side easily and thus you probably wouldn’t even need the high gear capability unless trying to outmaneuver another robot.

I voted 4 motor, 2 speed drive. Being able to push other robots shooters, or corner goal bots is going to be key. As long as this robot can get its initial 10 balls into the goal, it can spend the rest of the time playing very aggressive defensive and making sure the opposing team can’t score. Collecting balls off the ground while able to make or break a close game will not net you as many effective points as stopping the opposing team’s shooter.

Of course there is always the we can do everything vote. :slight_smile:

Go with picking balls up from the ground. I’ve never been a believer in human loading for the robots; the results of this week’s pracitce competitions confirms my worries. 2 speed can be done without anyway (we’ve never had it).

If you are single speed though, might you need to be geared slightly faster?

we were able to keep 9 motors on our robot, including 4 drive cim’s with 2 a speed shifter, without compromising any of our functions. We were 142 pounds at one point last week, but got her down to 119 by the end of the weekend :slight_smile: . Coyobot VII can pick up balls dump them, shoot them, and has a slick drive system.


I think you need a few mor options for your poll. Like for example:

6 motor drive train, single speed (but has power limit, which can be turned off), and a ground pick up decive.

Four motor - two speed.

Why? Because we could! We felt there’d be so many graizers that they’d spend much of their time getting in each other’s way. By running back home to reload we can take a good run at the center goal and fire early and often with ground speed added to the muzzle velocity.

One way to defend that would be to pull out in front of us - got bumpers?

Basically the question comes down to, “What’s more important for defense? Pushing, or ball hording?” Though I’m tempted to say the second, I’d have to go with pushing. If you don’t have pushing power, you can’t stop any robots. If you don’t have ball hording power, you are only vulnerable to floor picking robots. Judging from the number of teams that I assume are forgoing floor picking, (such as, say, The ThunderChickens) you are better off with a strong drive train to defend against them.

I am slightly confused here, These options are not very separated from each other. What I mean is I have seen robots with 4 motor 2 speed drive trains that have ball pickup systems.
I would like to then choose the “both of best worlds” options.
But for the sake of hypothetical questions, I will go with the 4 motor 2 speed drive train.
Call me biased, I am a 4 year driver :stuck_out_tongue:

The two speed drive sounds good, but is you gear “just right” you don’t need two speeds. Pushing and speed can both come from a good designed drivetrain. Trying to find that design has and will take time for any team.

I don’t believe this is a hypothetical question. I think Dave is trying to decide how to best use the limited resources they’ll have available at their first competition.

That is part of the reason I am confused. Is this in fact a “What do you think my team should do?” question? Having to do with a lack of weight to have all systems incorporated?

The question as it stands without any back round information is what I would call hypothetical.

Have you thought about using the Dewalt XRP Transmissions? Team 228 is using them this year; since we are only using two small CIMs and two Dewalt transmissions for our drivetrain, we had plenty of weight left over for a floor ball gatherer. The Dewalts on our robot are geared for a stump-pulling 3ft/sec, a moderate 8ft/sec and zippy 12ft/sec through the Dewalts.

From the othe posts made about their robot barely being finished, and from the picture, I gather that this IS a question on what they actually should do.

One thing that might assist this question; how good do you believe your human players are?

You can push people around all day but that doesn’t get you any points. I’ll go with 2 speed and a manipulator.

the second option is pretty much on our robot right now
we originally had 2 motors in the kit transmissions but then took one motor out of each to save weight.

we also used a globe moter to run our ball conveyer system

Our bot this year actually has 4 motor 2 speed drivesystem and can pick up off the ground, so I guess that we would be a bit of both. For defense, we plan on just getting in the opponent’s face and picking up balls every now and then if they happen to roll to our collector.

If I was in a situation though, I would go with the 4 motor 2 speed, I’m head of drivesystem and a driver.:smiley:

Yeah, we have a 4 motor 2 speed drive with ground pickup. I suppose if I had to choose, I would go with the beefy drivetrain, since human loader isn’t much slower than ground pickup, and the ability to impose your will on other robots is a useful one.

Well, since we had 19 cents in our budget at the beginning of the year (we ended up spending a bit over $1,000), we were forced into the kit box (don’t get me wrong, it’s a fine gearbox, but it isn’t a DeWalt). Since I didn’t think we’d have an awe inspiring shooter I used all four little CIMs in the kit 'box, six kit wheels, some SBR Roughtop treading, two more tranny sprockets, and eight AndyMark 54 tooth sprockets to make a 5.7 ft/s (in theory, it’s probably a little lower) six wheel drive. So, we can play some rough defense, our ball pickup mechanism is ground capable (polycord conveyor), so we can harvest, and our shooter… doesn’t work very well. It can hit the bottom goal from >30 feet, but can’t get the top goal. So, although it wouldn’t matter now if this isn’t hypothetical, I’d say do 'em all. Failing that… I don’t know… I literally flipped a coin for my poll choice.

2 and ground pickup. Why? Flexiblity.

You may not be the fastest, or most “torqu-ie”, but you can play backfield. You can human load. You can floor load. You can get in peoples way, even if you just get pushed back. Just gives you options. More options. And since we don’t REALLY know how the game will be played yet, options are good.