pic: RED DRAGON Team 1270

Next year we plan on using 6” IFI wheels and bumpers.

Why 6" wheels next year?

Also, did the frame style make working on the drive difficult?

I dont know if this is the reason or not, but we got into a pushing match with them on curie and we couldn’t win. By some random stroke of luck, we managed to actually drive over the upper surface of their robot. If it was taller we wouldn’t have been able to do that.

that would be a poor reason to change. They had a perfectly legal design with many advantages (robust, low cg). To change because of another team is a bad idea.

The reason for 6" wheels is to get more speed out of the robot.

Yes, it was difficult. Yet, once everything was in place the robot was bullet proof. The only thing we had to do was change out the tread material after each regional.

This team had a very unique drivetrain. It was one of the robots that we actually were afraid of pushing. They were great to watch this year

I wouldn’t say its “perfectly legal”. Let me preface this by saying this is only my interpretation of a rule (ever since the rule came out in 2006). I have never seen anyone (including myself, I’m a RI) enforce this 2 year old rule as per my interpretation nor any indications that this would be correct way to enforce it.

Here is <R05> with one sentence my emphasis:

<R05> "Wedge” ROBOTS are not allowed. ROBOTS must be designed so that interaction with opposing ROBOTS results in pushing rather than tipping or lifting. Neither offensive nor defensive wedges are allowed. All parts of a ROBOT between 0 and 8.5 inches from the ground (the top of the BUMPER ZONE) that are used to push against or interact with an opposing ROBOT must be within 10 degrees of vertical. Devices deployed outside the ROBOT footprint should be designed to avoid wedging. If a mechanism or an appendage (e.g. a harvester for retrieving GAME PIECES) becomes a wedge that interferes with other ROBOTS, penalties, disabling, or disqualification can occur depending on the severity of the infraction.

I interpret this to mean all (4) robot sides must be at least 8.5 inches off the floor and those sides must be within 10 degrees of vertical. If the “top” of your robot is less than 8.5 inches, then it is 90 degrees off vertical (it is horizontal) and doesn’t satisfy this rule.

Now you might say the “top” of the robot is not meant to be interact with other robots. I would say it may not be designed to interact with other bots, but in fact it often does. It will get under bumpers and high ground clearance bots and act as a wedge. It is a form of “wedge” that just doesn’t look like one.

In an odd twist, I have seen bots with a short flat side with a slope above it get called on this (usually after flipping a bot). Does the slope above the short flat side make it worse? I don’t think so, it just looks more like a “wedge”. To take it to the extreme case what would you think of a bot whose front had a large piece of sheet metal mounted horizontally a 1/4 inch off the ground?

There are obvious problems with my interpretation. Mainly it makes many “kit bots” illegal unless they make the sides flush or add bumpers. It is kinda cruel to give teams parts in the kit that once assembled will likely be illegal.

My proposed solution, make standard bumpers a requirement (you can still segment them to accommodate manipulators). Everyone should be able to build them and they would solve many robot interaction problems. Either way I feel this is a rule that needs clarification since there are still wedgelike bots out there.

This post is by no means meant to single out the Red Dragons. I had the pleasure of watching them compete and represent Curie well. Despite what happened, I felt they showed very good sportsmanship and their conduct on the CD boards only reinforces my impression. This <R05> issue reentered my mind after the finals and I have been debating about posting it. Since the issue was being discussed here, I couldn’t resist the urge to add my 2 cents.

I would have to disagree with you on this one. As I understand it, 0 - 8.5in is the “bumper zone”. I would imagine the intent of this rule is so that no surface in the bumper zone is sloped, to prevent robot tipping. Therfore, no surface in this zone can be sloped (more than 10 degree off vertical). Also, it says specifies this rule only for “that are used to push against or interact with an opposing ROBOT”. As you said, 1270’s frame top probably isn’t intended as a pushing surface.

Something else to consider is that a robot with bumpers mounted as low means the top of the bumpers are 7.5in off the ground, which would put them in violation of the rule by this interpretation. I can see your point though about short robots being wedge-ish (our robot was accidentally flipped by another team’s bumpers). It is something FIRST may want to clarify future manuals.

Back on topic though, I absolutely loved this drive train. Compact, relatively simple, and rock solid. How much does it weigh as pictured, and where can we find more pictures/ Inventor drawings of it?

Standard bumpers are 5 inches and must be mounted between 2.5 and 8.5 inches off the floor “The Bumper Zone”. That would make their lowest configuration 7.5 inches at the top and 3 inches taller than a 4.5 inch high bot. Unfortunately, many teams mount their bumpers too high or too low and don’t know where “The Bumper Zone” is. I think they will fix this with experience.

Bumpers are soft (and absorb impact) so they don’t have a tendency lift other bots during bumper to bumper collisions. One problem is they get stuck on top of each other if one robot is rocking, but that really cant be avoided. I would also like to see slick (non cloth) surface bumpers as an option for those who don’t want defenders “sticking” to them.

I don’t mind criticisms of my interpretation, I know I’m in the minority. It was was my immediate impression of the rule and I have never seen anything to lead me to believe otherwise.

You present an interesting argument.

However, the rules do not demand bumpers and the Red Dragon base is vertical as specified by the rules: “<R5>…All parts of a ROBOT between 0 and 8.5 inches from the ground (the top of the BUMPER ZONE) that are used to push against or interact with an opposing ROBOT must be within 10 degrees of vertical”

The Red dragon sits .5 inches above the ground and is below the 8.5 inch bumper zone. So, the area that is used for pushing is legal. The Red Dragon is not a wedge.

One may argue that robots that drive over other robots are in violation of the following rule:

<G35> Contact outside of the BUMPER ZONE is generally not acceptable, and the offending ROBOT will be assessed a 10-point penalty, and may be disqualified from the match if the offense is particularly egregious or if it results in substantial damage to another ROBOT.

The bottom line is that the referee that makes the call and is shielded from any consequences. The ruling is final. Like it or not – no recourse is really available!

Thanks for your support!

Well, we’re rehashing a rule for a game that has passed, which is not particularly productive… aside from the fact that it does highlight an ambiguity that the GDC may want to tighten up for next year.

However since we’re having a bit of fun examining this rule, I believe the GDC posted to the Q&A explaining that the “bumper zone” consisted of the space between two planes… one 2.5 and the other 8.5 inches off the field. This means that if a robot accidentally drives on top of another very low robot then the contact did occur within the bumper zone… even though it occurred on a horizontal surface within the bumper zone that was not intended to push or interact against other robots… meaning that <G35> does not apply. The contact was INSIDE the bumper zone.

It is an academic argument at this point, of course. On a general note, however, while requiring ALL teams to use standard bumpers eliminates some design choices (and just try finding pool noodles in Canada in winter… it can be done, but they aren’t that common…) and is not something I’d really like to see, I can heartily recommend that bumpers make life happier.