Effective Drive Base

[Al Skierkiewicz]

The BUMPERS must be located entirely within the BUMPER ZONE when the ROBOT is standing normally on a flat floor, and must remain there (i.e. the BUMPERS must not be articulated or designed to move outside of the BUMPER ZONE).

I think this is the effective part of the rule.

[Brandon Holley]

Originally Posted by Al Skierkiewicz

The BUMPERS must be located entirely within the BUMPER ZONE when the ROBOT is standing normally on a flat floor, and must remain there (i.e. the BUMPERS must not be articulated or designed to move outside of the BUMPER ZONE).

I think this is the effective part of the rule.

I agree...I think that is a very important part of the rule. The part I don't like is "the BUMPERS must not be articulated or designed to move outside the BUMPER ZONE". To me this means that you shouldn't design your robot or mechanism on your robot such that the bumpers could move.

Originally Posted by M80

I think that treads provide too high a probability of falling off the bot on turns. I think the grip wheels that came with the kit are the best option

I would research the design of a proper tread system further before simply ruling it out. A proper tread system won't fall off on the turns, only a poorly designed one will.

[craigboez]

How about discussing the different drive base styles relative to a strategy? It would seem that what works well for a "goalie" robot may not work well for a "midfield" or "forward" robot.

For a goalie, an omni-drive may make the most sense. You'd never have to traverse a bump and could shuttle from side to side with ease, clearing out balls as they came into the zone. As a mid-fielder a more powerful system may be better. I have a feeling that in the mid-field zone there will be lots of contact and jockeying for position beneath the ball returns (almost like boxing out in basketball after a free throw). As a forward, you'll want high accuracy and agility, but probably also want the ability to return to the midfield zone and help out if necessary.

Sorry for all the sports references, but it seems like that is the kind of teamwork they're nudging us toward this year. Specializing at doing a portion of the tasks particularly well will likely lead to an alliance selection, and if all goes well your alliance will do a good job of putting together a team of goalie, midfielder, and forward (all of which will, I'd imagine, look fairly different from one another).

Thoughts?

[Passion]

Originally Posted by craigboez

How about discussing the different drive base styles relative to a strategy? It would seem that what works well for a "goalie" robot may not work well for a "midfield" or "forward" robot.

For a goalie, an omni-drive may make the most sense. You'd never have to traverse a bump and could shuttle from side to side with ease, clearing out balls as they came into the zone. As a mid-fielder a more powerful system may be better. I have a feeling that in the mid-field zone there will be lots of contact and jockeying for position beneath the ball returns (almost like boxing out in basketball after a free throw). As a forward, you'll want high accuracy and agility, but probably also want the ability to return to the midfield zone and help out if necessary.

Sorry for all the sports references, but it seems like that is the kind of teamwork they're nudging us toward this year. Specializing at doing a portion of the tasks particularly well will likely lead to an alliance selection, and if all goes well your alliance will do a good job of putting together a team of goalie, midfielder, and forward (all of which will, I'd imagine, look fairly different from one another).

Thoughts?

I agree with you. Teams would have to design their robots based on where they want to play at, either front, mid or far back. It seems almost impossible and time is very limited to make a robot that is able to do EVERYTHING. Strong specialization in a particular zone is important.

[ebarker]

so what would be the disadvantage of 6 in wheels beside the obvious ground clearance problem when going over the bump ?

and what would the disadvantage be with mechanum ?

[fuzzy1718]

a page or two back some one said that 4 wheel drive is hard to turn with
2006, 2007, 2009 (with traction wheels added) our team turn just fine with 4 wheels... granted we were in the wide configuration, but it is actually better at turning than a typical 6-wheeler (don't quote me on the being better part, in our experiance it is better, which is limited to 2 chassis in the 6 wheel genre)

[T3_1565]

I've never had a problem turning with 4wd either. Not sure what the fuss is about.

[Shawyan]

Our team has mainly had problems with the KoP chassis while using 4 wheel drive. The robot consistently hopped 4-6 inches off the ground. This was done with high traction wheels, which may have been the problem. This hop was greatly reduced with a welded chassis instead.

The turning with a 4WD, in our team's opinion, has never been superb.8WD would be much more efficient, and easier to travel over the bump as well.

[Akash Rastogi]

Originally Posted by fuzzy1718

a page or two back some one said that 4 wheel drive is hard to turn with
2006, 2007, 2009 (with traction wheels added) our team turn just fine with 4 wheels... granted we were in the wide configuration, but it is actually better at turning than a typical 6-wheeler (don't quote me on the being better part, in our experiance it is better, which is limited to 2 chassis in the 6 wheel genre)

Simple physics and extensive experience with both types of drivetrains does not lie. Your wide orientation made the difference, by the way.

If you can't prove your logic to me then I highly suggest you learn the physics behind it and read this....

http://www.chiefdelphi.com/media/papers/1443

Note that the words "hard to turn" and "harder to turn" make a difference too.

Disclaimer: I am not taking into account possible varying CoF between the front and back sets of wheels.

[T3_1565]

I always found 6wd and 8wd to have a harder time turning then 4wd. more points of contact = more friction... making it harder to turn.

toss up between getting over the bump easy and driving easy.

[Akash Rastogi]

Originally Posted by T3_1565

I always found 6wd and 8wd to have a harder time turning then 4wd. more points of contact = more friction... making it harder to turn.

toss up between getting over the bump easy and driving easy.

6 wheel drive, drop center is the case in point.

On the matter of 8wd, I can't comment yet because I lack the experience in this type of drivetrain.

[MrForbes]

Originally Posted by Akash Rastogi

On the matter of 8wd, I can't comment yet because I lack the experience in this type of drivetrain.

but I think a lot of teams are going to know something about it by this time next week

[Brandon Holley]

Originally Posted by T3_1565

I always found 6wd and 8wd to have a harder time turning then 4wd. more points of contact = more friction... making it harder to turn.

toss up between getting over the bump easy and driving easy.

More points of contact with less normal force at each point of contact. Its not as black and white as you described it.

[T3_1565]

Oh, well I never said I was an expert on the subject, just never found it hard to turn with a 4wd bot