We cant use OMNI’s or traction wheels, only the KOP wheels. any ideas of how to drive?
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
My guess would be to accelerate slowly to prevent burnouts, and distribute your weight on your back wheels.
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?
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.
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?
says it all. You may use only the KOP wheels.
they dident say that we couldent angle the wheels…
A holonomic drivebase would still be possible even with just the KOP wheels. The coefficient of friction is low enough that a swerve base or kiwi drive would both be possible, since the wheels slide easily enough.
thats exactly what i was thinking
I think it may be good to have weight on the driving wheels so that there is plenty of traction for turning and changing direction.
There is another rule stating that the wheel’s rotation MUST BE inline with movement of the bot, so that the axle the wheel is on is perpendicular to the bot and wheels movement
For tank drive systems, what do you guys think about 4 vs 6 coplanar, evenly spaced wheels? Would there really be any difference?
Has anyone felt the new playing surface? How much does it cost? Would plane old hallway concrete be a suitable substitute?
could you find this and link to it?
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.
The fewer wheels you have will actually increase you traction because you will have more weight on the drive wheels we are thinking about having a front wheel drive with one more wheel in the back. We would use a tank drive to be able to turn with the trailer.
Seems to me it says nothing about requiring the wheels be oriented so MOTION is in the direction of the tread, only that they be mounted with tread touching the floor (i imagine to foil us lateral thinkers that might try to cantilever the wheels and use the flat face of them to try to move forward)
im not sure how many of you out there live in the lovely area that gets a lot of snow. but im in new carlisle indiana. and we just get dumped on constanlty. one thing i’ve notices is front wheel drive cars tend to do better. you can power out of the slide (if you are able to do a car-like steering). and i have noticed that rear wheel drive causes a lot of fishtailing.(maybe not with the trailer). but the best by far is four-wheel drive. it gives you power to all four wheels. team 2197 is without a doubt going with four wheel drive. good luck to everyone. i hope you all have fun with lunacy
If you are talking about R06 I don’t read it that way. The tread must be in contact with the ground and the wheel axis must be parallel to the ground and through the wheel hub. However, this does not imply "inline. At first read, I do not see what rule would prohibit a crab steering configuration unless I missed something.
One thing to watch for when designing the robot is turning ability when using skid steering (tank drive).
If you notice the coefficients of friction for the wheels, you will see that inline dynamic is .05 while transverse dynamic is .10. In a skidding situation the wheel will be twice as resistant to going sideways as it is to going forwards…
That means, as I read it, that your wheel is not going to want to slide sideways very easily if you use 4wd tank drive.
In fact anyone planning on going with skid steering will probably want to really look at using at least six wheels to minimize the amount of skidding required in a turn.
Jason