How can we drive on this new floor?

[sPod]

We cant use OMNI's or traction wheels, only the KOP wheels. any ideas of how to drive?

[Jay H 237]

The same way you would as if you were driving on snow or ice. It is possible and start off slow to get going.


I think the teams in the snow belt areas will have an advantage with the 2009game

[Seat Ninja]

My guess would be to accelerate slowly to prevent burnouts, and distribute your weight on your back wheels.

[Lesman]

Well, it's obvious that every wheel touching the ground will need to be powered (otherwise you're foolishly wasting precious traction) but beyond that I don't have many ideas. Would any non-tank drive style drive systems help? Also, am I wrong in assuming that traction force is just a function of coefficient of friction (cannot be changed) and mass (going to be 120 for everybody)? Does increasing the surface area have any affect?

[pyrome]

There are even a few more factors than that in optimizing traction.
However, to put it simply:
Friction is a function of normal force (weight).
Traction is a function of normal force AND surface area.

[eNyoron]

You can add more traction to the wheels by adding downward force onto the wheels. Any additional weight would be dispersed by the wheels regardless of where it's centered unless the robot has another point of contact with the ground (or if it goes all the way through the trailer). So you could add force with springs or with pneumatics, thereby adding traction.

But I'm wondering, could you propel yourself by say, pushing off of walls? There have got to be some ways to move outside of the traditional wheels on the ground that are still legal within the competition constraints.

[rl1806]

Would there be any advantage in using crab drive or another drive system like that? Or would a car like drive system be better for towing the trailer around?

[Bryan Herbst]

Originally Posted by Jay H 237

The same way you would as if you were driving on snow or ice. It is possible and start off slow to get going.


I think the teams in the snow belt areas will have an advantage with the 2009game

I have to agree.

To teams that have no experience driving in snowy/icy conditions- trying to start out going fast (even middle-range speeds) can result in either your tires just sitting there spinning, followed by a jerk forward, or the car/bot sliding out of control.

[mray1031]

Anyone thinking about workarounds to the traction problem?

If the total traction is a function of your friction, surface area, and weight, and friction is fixed- shouldn't we be looking at surface area and weight?

Surface area is easy- more wheels (I don't think there's a limit)

But weight? could be interesting. Any ideas?

[mray1031]

oh man. people are posting fast i guess my last one was outdated...

since people are already thinking about pluses and minuses of weight anyone consider varying the "weight" of your robot?

[dmlawrence]

In theory, one could construct giant omniwheels using each Rover Wheel as one of the horizontal rollers...

[Branden Ghena]

Originally Posted by dmlawrence

In theory, one could construct giant omniwheels using each Rover Wheel as one of the horizontal rollers...

While a great idea...

Originally Posted by FRC 2009 Game Manual
<R06>
ROBOTs must use ROVER WHEELS (as supplied in the 2009 Kit Of Parts and/or their equivalent as provided by the supplying vendor) to provide traction between the ROBOT and the ARENA. Any number of ROVER WHEELS may be used. The ROVER WHEELS must be used in a “normal” orientation (i.e. with the tread of the wheel in contact with the ground, with the axis of rotation parallel to the ground and penetrating the wheel hub). No other forms of traction devices (wheels, tracks, legs, or other devices intended to provide traction) are permitted. The surface tread of the ROVER WHEELS may not be modified except through normal wear-and-tear. Specifically, the addition of cleats, studs, carved treads, alterations to the wheel profile, high-traction surface treatments, adhesive coatings, abrasive materials, and/or other attachments are prohibited. The intent of this rule is that the ROVER WHEELS be used in as close to their “out of the box” condition as possible, to provide the intended low-friction dynamic performance during the game

I think the emphasized part of R06 might disallow that, along with the general logistics of building giant omniwheels.

[darkpheonix]

In response to adding weight without adding weight, you could add fans to the bottom of the robot to draw in air from the bottom, just like those cars that can climb walls. Don't know how much it would increase the normal force though.

[Mike8519]

Originally Posted by darkpheonix

In response to adding weight without adding weight, you could add fans to the bottom of the robot to draw in air from the bottom, just like those cars that can climb walls. Don't know how much it would increase the normal force though.

Reading R06... It says to me that no devices at all (making contact or not) may be used as a "traction device". The intent is that all robots have similiar traction on the surface. Increasing your force via suction would be a "traction device" in my mind

[mray1031]

zyck I think you and I are on the same train of thought. Still wondering about how to implement it though. Lets see if anyone else comes up with it.

Btw. Has anyone thought of just hanging out in the carpet and speeding around everyone? you'd have to be a great shot with those balls but it would be tough to score on you