Effective Drive Base

[Collin Fultz]

Originally Posted by Taylor

I would love to see a version of 2004-71 style swerve.

Is this possible with the BUMPER ZONE rules as they are? Would articulating your wheels change your BUMPER height?

[Chris is me]

Originally Posted by Collin Fultz

Is this possible with the BUMPER ZONE rules as they are? Would articulating your wheels change your BUMPER height?

This is the reason I ruled it out as a possible design. Bumpers ruin everything.

[Al Skierkiewicz]

We need to remember that the bumper zone is elevated this year, 10-16 inches above the floor when on a flat surface and may not be articulated.
8.2 DEFINITIONS
BUMPERS – Bumper assemblies designed to attach to the exterior of the ROBOT within the BUMPER ZONE, and constructed as specified in Rule <R07>. BUMPERS are excluded from the weight and volume calculations specified in Rule <R10>.

BUMPER ZONE – the volume contained between two virtual horizontal planes, ten inches above the floor and sixteen inches above the floor.

<R07>
A. BUMPERS must provide complete protection of the entire FRAME PERIMETER of the ROBOT (i.e. BUMPERS must wrap entirely around the ROBOT). 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).

If one uses 6 inch wheels, then the drive assembly would need to be a good distance behind the frame perimeter for any bumper to interfere with climbing. (The top of the bump is 12 inches high but also 12 inches set back from the base) This does not appear to rule out any type of drive system that would take into account the shape and height of the bump. As to whether a crab drive would succeed on the bump over a different drive system is up to the team to prototype and then make a decision. As is discussed in several other places, high center of gravity seems to be the more important issue if choosing to climb the bump. Considering all of the factors summed together, it appears to be a considerable challenge to design a robot that both climbs over the bump or drives through the tunnel.

[CHapstack]

My team has been doing some testing to see which drivetrain handles the bump best when driving over it at an angle (we assume that we won't be able to hit the bump perfectly straight every time). We have prototyped a few ideas, including 8WD with raised end wheels. Has anyone else considered how their drivetrain will work when driving over the bump at an angle (or if their robot gets hit when driving over the bump)?

[Brandon Holley]

Originally Posted by Al Skierkiewicz

<R07>
A. BUMPERS must provide complete protection of the entire FRAME PERIMETER of the ROBOT (i.e. BUMPERS must wrap entirely around the ROBOT). 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).

If one uses 6 inch wheels, then the drive assembly would need to be a good distance behind the frame perimeter for any bumper to interfere with climbing. (The top of the bump is 12 inches high but also 12 inches set back from the base) This does not appear to rule out any type of drive system that would take into account the shape and height of the bump. As to whether a crab drive would succeed on the bump over a different drive system is up to the team to prototype and then make a decision. As is discussed in several other places, high center of gravity seems to be the more important issue if choosing to climb the bump. Considering all of the factors summed together, it appears to be a considerable challenge to design a robot that both climbs over the bump or drives through the tunnel.

Heres my problem with the rule...when your robot negotiates the bumps, or hangs from the bar, your bumpers will no longer be in the bumper zone. Thus aren't you violating R07?

[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

[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 ?

[Shawyan]

Originally Posted by hipsterjr

We designed these articulating drive pods back in 2005 and have been waiting for a game like this to use them.

Wow. Simply amazing drive train.

I believe the best overall drive train is either full holonomic or Swerve drive. This would allow being able to rotate the robot to face the goal, as well as drive in the desired direction. Swerve drive allow the team to keep more motors free for other activities such as a kicker, but still retain the "any direction i want, i go, no worries".

Also, I do not see the reasoning behind why having smaller wheels will make it more difficult to go over the bump, as long as the wheels are extended further down. Though 4 inches may be pushing it.

[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.