WHEEL TRACTION--PLEASE RESPOND

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Posted by Jason Wolf at 2/10/2001 12:24 PM EST


Student on team #375, Robotic Plague, from Staten Island Technical HS and Verizon.



Hi,
Anyone have any suggestions upon how to add traction to the wheels? We have 2 8" wheels in each corner running with 1 motor per side with chain extending to each axle, so sort of a tank drive system. We need more traction though due to pushing and pulling the goal and stretcher, please respond with any ideas....Thanx
Jason
Team 375

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Posted by Michael Martus at 2/10/2001 3:03 PM EST


Coach on team #47, Chief Delphi, from Pontiac Central H.S. and Delphi Automotives Systems.


In Reply to: WHEEL TRACTION--PLEASE RESPOND
Posted by Jason Wolf on 2/10/2001 12:24 PM EST:



To have more traction you will need more surface on the carpet or a lower gear with the weight over them.

Look at the placement of your weight in relationship to your location of the drive system.

Spinning means loss of traction. Think of drag racers, they run on very low pressure tires with wide surface - slicks!

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Posted by Dan Richards at 2/10/2001 6:43 PM EST


Student on team #550, WCTS Robotics, from Warren County Vo-Tech and WCTS.


In Reply to: Re: WHEEL TRACTION--PLEASE RESPOND
Posted by Michael Martus on 2/10/2001 3:03 PM EST:



I agree with Jason. To get more traction, you need more surface. Grind down the tires so they're one wide surface. Do a burnout for ten minutes on sand paper with 50 or so pounds of weight over each wheel, and immobilize it. That will do it. Or you can just use a grinder. depends on if you want it to be 'legal'.

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Posted by Joe Johnson at 2/10/2001 10:52 PM EST


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.


In Reply to: More Traction
Posted by Dan Richards on 2/10/2001 6:43 PM EST:



It all comes down to 2 things really:

How much weight can you keep on your drive wheels.

How good is your grip given that weight.

You have to have both. Work to maximize both and you
will be okay.

Joe J.

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Posted by Vince Wilczynski at 2/11/2001 12:26 PM EST


Engineer on team #124, Whalers, from New London / Montville/ Williams School and Notheast Utilities / US Coast Guard Academy.


In Reply to: Weight on wheels and better grip...
Posted by Joe Johnson on 2/10/2001 10:52 PM EST:



Small Parts sells some "anti-slip" material that we've used in the past. It is the non-skid used on stairs and one side has adhesive. You have to be careful putting it on the Sky-Way wheels (i.e. smooth, clean, and then carefully apply) but when you do it works well. In normal operation, it doesn't tear up the field. If you need to test-out the material and don't want to wait for the SP order, most Home-Depot stores carry the material (in their paint department).

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Posted by Shawn McMahon at 2/12/2001 5:23 PM EST


Student on team #263, Aftershock, from Sachem H.S. and Symbol, Citycorp., Apoge, CA ....


In Reply to: Anti-slip in Small Parts for grip
Posted by Vince Wilczynski on 2/11/2001 12:26 PM EST:



You can also wrap the wheels in a nice sticky rubber. I don't mean sticky as in glue, thats illegal, but sticky as in great grip. We were able to find some nice tank tread (pulley belts) and wrap custom made wheels with it. I would suggest making your own wheels if you don't get the desired traction. They're not terribly difficult to make and you can make them as wide as you can fit.

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Posted by Dennis Hughes at 2/13/2001 10:33 AM EST


Other on team #27, Team Rush, from OSMTech Academy & MTA and TEXTRON Automotive.


In Reply to: Sticky wheels
Posted by Shawn McMahon on 2/12/2001 5:23 PM EST:



: You can also wrap the wheels in a nice sticky rubber. I don't mean sticky as in glue, thats illegal, but sticky as in great grip. We were able to find some nice tank tread (pulley belts) and wrap custom made wheels with it. I would suggest making your own wheels if you don't get the desired traction. They're not terribly difficult to make and you can make them as wide as you can fit.

Shawn,
Where did you get the "tank tread " timing belt? Is it a gum rubber type mat'l which your using to contact the carpet. We looked for Natural rubber type timing belt but didn't find anything. Did you??

Thanks
Dennis

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Posted by Raul at 2/13/2001 1:32 PM EST


Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.


In Reply to: Re: Sticky wheels
Posted by Dennis Hughes on 2/13/2001 10:33 AM EST:



Actually, I asked Eric (at FIRST) and he varified that fasteners, including adhesives, can be used in any function this year. The only issue he mentioned is that it not leave residue on the carpet, otherwise they will ask you to remove it from your wheels.

Raul

: : You can also wrap the wheels in a nice sticky rubber. I don't mean sticky as in glue, thats illegal, but sticky as in great grip. ...
:

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Posted by Bob Drexel at 2/10/2001 9:23 PM EST


Engineer on team #358, Titans, from Hauppauge and Festo Corp..


In Reply to: WHEEL TRACTION--PLEASE RESPOND
Posted by Jason Wolf on 2/10/2001 12:24 PM EST:



The wheels have a very small contact area when stock due to the radius profile. Put them on a lathe and turn them down. This will significantly increase the surface area. Then use a soldering iron to create a tread pattern. The frictional coefficient will increase dramatically.

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Posted by Ken Leung at 2/11/2001 5:21 AM EST


Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.


In Reply to: WHEEL TRACTION--PLEASE RESPOND
Posted by Jason Wolf on 2/10/2001 12:24 PM EST:



Just a couple of things you want to look at.

As other people said before, you want to increase your area of contact with the carpet so that you can have a bigger possibility of maximizing your friction force from the wheel. Like another person said, you can lathe the wheels flat to have more contact area. But another way of doing it is to add more wheels, so that the chain will be driving two wheels on one side instead of two, which basically mean you have a wider wheel.

A second thing is to increase friction on your wheels. You can do a couple of ways. You can try cutting grooves into the wheels, either horizontally or some kind of pattern like tires. Or, you can order some timing belt and add them onto the wheel so that the nods on the timing belt will be pushing against the carpet. A third way I can think of is to use some screw and mount them along the wheel, so the screw head will be gripping onto the ground. But you have to be really careful about this: You want to make sure you are allowed to use screws in this function (instead of a fastener) or else you will have to buy them from small part. Make sure you are not damaging the carpet doing this, and you want to make sure the screws don't come off or else you will be leaving part of your robot on the field.

A third thing is to add more weight on the side of the wheel. After all frictional force depends on mass. You can either shift weights toward the wheel side, so that the over all weight are pushing more on the wheels instead of being supported by caster or something. And/Or you can just add more weight on the robot in a general place, depends on what kind of space and weight limit you have. But you want to watch out if your wheel axle can handle the weight stress.

The last thing is that, as Michael Martus said, you might want to have a slower drive train. Not necessary reducing the power output to the motor, but to physical gear down the speed of the drive train.

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Posted by James at 2/14/2001 10:44 AM EST


Coach on team #21, ComBBAT, from Brevard Community College and Boeing.


In Reply to: WHEEL TRACTION--PLEASE RESPOND
Posted by Jason Wolf on 2/10/2001 12:24 PM EST:



Rubber Baby Buggy Bummers, check out small parts, and team 21s previous robots