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Here is one of our Polycarb wheels on our 2010 robot. We wanted them to weigh as much as possible to give us a low center of gravity, so they weigh about 2lbs each.
Discussion
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25-02-2010 18:58
Re: pic: MORE Robotics 1714 Polycarb Wheels
Low center of gravity is good and all, but have you considered how the added weight will effect your acceleration with this year's tight quarters on the field?
25-02-2010 19:59
O'Sancheski
Re: pic: MORE Robotics 1714 Polycarb Wheels
wow...those things are nice... i wish that our wheels were that light
25-02-2010 21:30
Thermal
Re: pic: MORE Robotics 1714 Polycarb Wheels
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Originally Posted by O'Sancheski
wow...those things are nice... i wish that our wheels were that light
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I mean, 2lb isn't exactly light for a wheel
25-02-2010 21:54
O'Sancheski
Re: pic: MORE Robotics 1714 Polycarb Wheels
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Originally Posted by Thermal
Wait, you wish your wheels were 2lb a piece? What are you using? Mecanums? If so you're not too far off at 2.5lb a piece..
I mean, 2lb isn't exactly light for a wheel |
26-02-2010 08:46
IKE
Re: pic: MORE Robotics 1714 Polycarb Wheels
Is this a 3 piece wheel, or a single piece?
If it is a single piece, what are the lateral screws for.
Beautiful wheels guys.
26-02-2010 12:12
AJ R
Re: pic: MORE Robotics 1714 Polycarb Wheels
The wheels are layers of polycarbonate. Solid one inch material is expensive. As far as the weight, 2 pounds is an estimate, so I will weigh one at the meeting tomorrow.
26-02-2010 15:40
IKE
Re: pic: MORE Robotics 1714 Polycarb Wheels
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Originally Posted by AJ R
The wheels are layers of polycarbonate. Solid one inch material is expensive. As far as the weight, 2 pounds is an estimate, so I will weigh one at the meeting tomorrow.
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26-02-2010 15:47
JamesCH95
Re: pic: MORE Robotics 1714 Polycarb Wheels
Nice lookin wheels. Though if you wanted them to weigh as much as possible steel is a nice and dense material... 
27-02-2010 01:36
Laaba 80
Re: pic: MORE Robotics 1714 Polycarb Wheels
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Originally Posted by JamesCH95
Nice lookin wheels. Though if you wanted them to weigh as much as possible steel is a nice and dense material...
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Just in case you have not seen any of our robots before, we try to build as clear as possible.
27-02-2010 01:59
Akash Rastogi
Re: pic: MORE Robotics 1714 Polycarb Wheels
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Originally Posted by Laaba 80
http://www.chiefdelphi.com/media/photos/34998
Just in case you have not seen any of our robots before, we try to build as clear as possible. |
Ok ok bad pun. But I couldn't resist.
27-02-2010 07:45
JamesCH95
Re: pic: MORE Robotics 1714 Polycarb Wheels
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Originally Posted by Laaba 80
http://www.chiefdelphi.com/media/photos/34998
Just in case you have not seen any of our robots before, we try to build as clear as possible. |
Hehe.
27-02-2010 11:05
Molten
Re: pic: MORE Robotics 1714 Polycarb Wheels
I have to agree with Craig, there are definite acceleration issues when you increase the weight of a wheel. This happens because the added weight resists motion and will fight you every time you try to change your direction of rotation or speed of rotation. This means slower to get up to speed, slower to stop, and more force on everything that powers the wheel including the chain and axles.
I like the creativity to get the center of gravity lower, but I really think you should bring alternative wheels if these give you too much troubles in competition.
27-02-2010 14:11
Chris is me
Re: pic: MORE Robotics 1714 Polycarb Wheels
It wouldn't take that long to pocket these wheels if the weight became an issue, but knowing the guys on the drivetrain team this year, they probably took that into account when gearing, testing, etc.
27-02-2010 15:05
Ian Curtis
Re: pic: MORE Robotics 1714 Polycarb Wheels
Mass isn't the issue. It's the Moment of Inertia (resistance to spin, which is a function of mass and radius) that could be the issue.
Per my rough calculations, the moment of inertia of an AM performance wheel and 1714's Lexan wheel differ by about 25%, and the actual ratio is slightly lower than this as the AM wheel has extra material near the axle that I didn't account for. I assumed an AM wheel is a rim and 3 sticks that span the inner diameter and the lexan wheel was a solid piece of Lexan.
Since you guys have the robot, have you noticed any adverse effects on performance? I'm still of the opinion that these wheels are super slick.
27-02-2010 15:34
Chris is me
Re: pic: MORE Robotics 1714 Polycarb Wheels
Well, in this instance, the only thing that can change the moment of inertia on the drivetrain is the mass if the moment is too high. If it's too high for comfort, you could easily cut 12 ounces out of the wheel with a drill press and 6 holes while maintaining strength if they absolutely had to.
27-02-2010 15:52
Laaba 80
Re: pic: MORE Robotics 1714 Polycarb Wheels
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Originally Posted by Molten
I have to agree with Craig, there are definite acceleration issues when you increase the weight of a wheel. This happens because the added weight resists motion and will fight you every time you try to change your direction of rotation or speed of rotation. This means slower to get up to speed, slower to stop, and more force on everything that powers the wheel including the chain and axles.
I like the creativity to get the center of gravity lower, but I really think you should bring alternative wheels if these give you too much troubles in competition. |
http://www.youtube.com/watch?v=xQJvj--2NXg
That is a video of us driving, and if it seems a little slow to you, this is all in low gear. Unfortunatly, I didnt get any video of it in high gear, but trust me, for this game it is plenty fast.
Thank you for the advise though, I personally had no idea about wheel weight affecting mobility, however I am sure people on the drive train team took this into consideration when designing the wheels.
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