Re: How can we drive on this new floor?
 

Some of my team members and I calculated that using 2 sim's and suction cup properly you caould add an extra 600 pounds to your robot with ever touching the ground... Any Ideas?

Re: How can we drive on this new floor?
 

Shade of 2003.
Teams used suction cups to plant themselves at the top of the ramp. That worked for the first few matches and then after getting ran over by robots for a while the field surface got worn down a bit and the suction cups stopped working.
I suspect the same would happen this year as well.

Re: How can we drive on this new floor?
 

Yes, weight does help traction, but it is a legal addition to the robot to a limit. Increasing your traction beyond your idle state/curb weight I think would cause the issue.

Traction control is legal because it is increasing control electronically. Not changing the physical interaction between the playing surface and the rover wheels

Re: How can we drive on this new floor?
 

I see your point, but that math was done assuming that the suction cups are about 1/2 to 1/4 of an inch off the ground. They would be more like a hover craft in reverse then suction cups.

Re: How can we drive on this new floor?
 

I don't think it is useless. The maximum force that can be generated with the wheels for a max-weight robot is 26.7N. With some math, you can determine that 5N and 10N fans could be plausibly added to your robot, which would add 18% and 36% to the acceleration of a max-weight robot, respectively. Some of that would be eaten by the airstream hitting the trailer, but I think a fan approach could actually increase performance.

I think there is a reading of the rules where it would be allowed. Traction generally refers to the contact between a wheel and the ground. Fans aren't enhancing your traction with the field (and unless you have a quickly reversible fan, they actually hurt your braking performance), they are applying a force by pushing against the atmosphere. However, there are also readings of the rules where it wouldn't be allowed, and it'll have to wait until QA opens to see if they are allowable.

Re: How can we drive on this new floor?
 

Last year we were one of a few teams that used a vacume to pick up the ball so we have some experience with them. One of my friends on the team picked up the ball just using his mouth. He sucked on a vacume tube atached to a cake holder lid. With that much of a surface area he could pick up the ball for about 5 seconds.

Re: How can we drive on this new floor?
 

Does this make any sense? Six wheeled bot. Four corner wheels driving forward and two side centered wheels driving backward as needed. Or, one wheel dead center of bot that would spin oppisite as needed. Then hand the whole thing over to programers. They can make it work.

Re: How can we drive on this new floor?
 

Look, all the ideas with fans:

Why not take your 200 pounds of force going downwards, point that to a side, and use it as a means of propulsion? It would certainly be a lot more efficient than using the force to increase the traction (it will still be low traction).

-Vivek

Re: How can we drive on this new floor?
 

Would a holonomic drive system work well? I think it would make it easier to drive, but I don't know for sure. Here is a link to a picture of what I am talking about except that we would have to use the required wheels instead of the omnis. The required wheels should work as well though, because they barely have any traction.
http://wiki.chiefdelphi.com/media/0/..._holonomic.jpg

Re: How can we drive on this new floor?
 

You would have to use the wheels in the kit as the casters, the wheel would be huge and bulky but it could work. Now you have to know that an omni-drive works on the principle of wheel slippage. It is designed so that wheel casters slip.

Re: How can we drive on this new floor?
 

While this might make sense initially, holonomic actually starts looking very bad after viewing the COFs for the wheels.

Yes, the transverse COF is very low, but the inline COF is less than half of it! This means a holonomic drive robot (with the COG in the middle) theoretically wouldn't move at all! In practice, it might, but not much.

Re: How can we drive on this new floor?
 

That could be a problem. In general PID controllers have always been a robust and great way to move your robot. The problem is that the ideal way to control the motors is with some type of ramp input meaning that the integrator may or may not work as exactly the same.

Re: How can we drive on this new floor?
 

is the coefficient of friction independent of surface area or not?

i think more wheels equals more friction

Re: How can we drive on this new floor?
 

But the Fan is not providing traction, it's providing a weight force, making up for the lost 5/6 of weight

Re: How can we drive on this new floor?
 

In simple physics terms friction is independant of the surface area.

In reality because we are on a textured surface it may not be.

If the wheels are the same as last years kit wheels the surface is a soft compound. With sufficient weight on each wheel the soft compound will conform the the bumpy surface producing more friction than a wheel riding on the top of the bumps.

The question then is what is then optimal load on a wheel to obtain the most friction. A simple experiment can be designed to determine the optimal loading and therefor the optimal number of wheels.

If allowed the vacuume design is possible. Many schools physics departments have a 4' diameter hovercraft where the lift is achieved with a battery powered leaf blower. The leaf blowers run well for 10 minutes on a charge and can easily support a 250 lb load. I believe the battery supplied has sufficient energy to power the leaf blower and drive motors and increase the normal force and friction. You would need a fully charged battery for each match.

Since we are simulating 1/6 gravity on the moon and there is no atmosphere on the moon I suspect a vacuume design wil not be allowed.

It is possible to get used to driving on a low friction surface. Those who are used to driving on ice and snow understand the limitations. Keep in mind that when driving a car on ice you are in the car and have a, seat of your pants, feeing of what is going. You do not have this sensor input at a remote driving station.

It is possible and easy through programming to limit how fast you can accelerate and turn. It takes some time to get used to, like the first time you slam on the brakes of a car with anti lock brakes.