View Full Version : How many wheels are you going to use this year
midway78224
16-01-2009, 14:29
My team is testing a six to eight wheel drive this year. We are planning on useing only 1 motor on each side and chain them together with a toughbox that came in the kit. We still testing and prototypeing that right now.
CraigHickman
16-01-2009, 14:30
We've got 4 wheels on the robot, and 6 spares. I expect them to wear down quite a bit this season...
Pjohn1959
16-01-2009, 14:40
Based on the coeffienct of friction, we are using 4 wheels this year. The less points of contact on the new floor, the better.
midway78224
16-01-2009, 14:43
We are not sure what we are going with right now. Were still testing. So far we figure out less motors is better but we still testing a four, six, and eight wheel drive
6wd but only 4 points of contact with the floor at a time.:yikes:
qwertyuiop[]\
16-01-2009, 14:47
3wd with 4 wheels but only 3 on the ground at a time
Andrew Bates
16-01-2009, 14:48
6wd but only 4 points of contact with the floor at a time.:yikes:
So you're dropping the middle wheel?
ComradeNikolai
16-01-2009, 14:52
4 for the simplicity it affords; adding wheels would not, by our calculations, provide any benefit, but it does benefit us to have the simplicity of only driving two wheels on each side.
SpaceOsc
16-01-2009, 14:54
no 14WD option?:confused:
excel2474
16-01-2009, 14:58
Based on the coeffienct of friction, we are using 4 wheels this year. The less points of contact on the new floor, the better.
Why is this the case? Is it because there is more wheight on individual wheels?
GarrettF2395
16-01-2009, 15:12
Why is this the case? Is it because there is more wheight on individual wheels?
To give you the short answer... yes! :)
My team is going with a 6WD dropped center wheel for added maneuverability.
We are still playing around with how the wheels will be powered, but as of right now,
they are hooked up via Toughbox with a single motor per side.
Bob Steele
16-01-2009, 15:13
Based on the coeffienct of friction, we are using 4 wheels this year. The less points of contact on the new floor, the better.
You get the same traction no matter what number of wheels you use. It is just split between all of them... the total is the same...
In order for this to be true, force has to be able to be applied by all the wheels in contact with the floor. Any non-powered wheels will decrease the amount of force you can apply by lowering the normal force of the powered wheels.
The force you can apply to the floor is contingent in this game simply on the coefficient of friction and the normal force. These two do NOT change when you add more wheels.
In a game with a non-slippery or non-smooth surface I would agree that you MIGHT be able to influence the force you can apply to the floor ( and therefore the acceleration) by adding more wheels or more surface area...but in this game you can only apply the force you are "allowed" to apply by friction.
good luck in your designs!!!
On our team, I have voted for 4 wheels, each side driven by a motor. We have another contingent that wanted to have 8 wheels (2 in each corner). I say that won't help traction (for reasons stated above) and will make turning even harder because now you have two wheels locked together so one will have to slip in the direction of rotation during turns. It would be better to have three to a side, since the center wheel would take weight off the outside ones and help the robot to turn, but that complicates the drive train and we are running out of time.
Brian
MrForbes
17-01-2009, 10:31
Four, because it's probably not gonna make a difference...the chassis is already built (http://www.youtube.com/watch?v=Yb8IPQYp_M0), we have a LOT of work to do to get the ball handling stuff designed, built, programmed, tested and practiced. No time left for chassis this season for us...except for the traction control programming....
sdcantrell56
17-01-2009, 14:02
We're going with 6wd with a dropped center wheel on a wide oriented frame for maximum turning. We are also directly driving the center wheels off of a modified toughbox and chaining the outer wheels.
aaeamdar
17-01-2009, 14:27
I highly recommend that any teams planning to use wheels that will not always be in contact with the ground consider the implications of R06. I'm not a rules expert, and I haven't searched the GDC site to find if this question has been asked and answered, but I think a strict interpretation of R06 does not allow for wheels to be in contact with the ground only some of the time. To quote:
The ROVER WHEELS must be used in a "normal" orientation (i.e. with the tread of the wheel in contact with the ground[...] (emphasis mine)
It doesn't say that wheels must start in contact with the ground - it says they must be in contact with the ground, and doesn't seem to make any exceptions.
So, my overall point is, if you are planning to use wheels that are not in contact with the ground, please carefully consider the implications of this rule. If you have already asked on FIRST Q&A and received an answer, feel free to ignore me. Also, keep in mind that "everyone on Chief Delphi agreed that it meant X" is not going to matter to the inspectors.
Best to everyone
Paul
6wd but only 4 points of contact with the floor at a time.:yikes:
Same, though we might use some sort of suspension to keep all 6 on the ground at the same time, but do not take on much weight.
Mikesername
18-01-2009, 14:11
Crap I choose 2 on accident... we're using 4 wheels, with one motor on each side. Each motor will be chained to two wheels, with one chain.
shadow1083
05-04-2009, 14:08
10 wheels. 2 motors. Tank drive.
Matt Howard
06-04-2009, 13:17
6 Wheels, front two raised 1/4 inch from the floor, back 4 driven.
AdamHeard
06-04-2009, 14:11
We've been using 48 all season and it's been working well enough for us.
We've been using 48 all season and it's been working well enough for us.
Are you Serious? If so Pictures would be awesome.
We are using 6 wheels total. 2 per crab swivel up front (4 total in front) with 1 wheel per stationary mount in the rear (2 total in back).
Aren_Hill
14-04-2009, 15:58
Are you Serious? If so Pictures would be awesome.
We are using 6 wheels total. 2 per crab swivel up front (4 total in front) with 1 wheel per stationary mount in the rear (2 total in back).
their pickup rollers are lined with little rc car tires, taking advantage of the original poster not specifying "rover wheels"
their pickup rollers are lined with little rc car tires, taking advantage of the original poster not specifying "rover wheels"
Ahhhh that explains it. Tricky :P
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