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Unread 30-10-2014, 09:54
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Re: Need general drive train expertise

Quote:
Originally Posted by Ether View Post
Changing the weight will likely affect the rolling resistance of the bot, especially on carpet.

If you change the rolling resistance parameter(s) in the model accordingly, it will affect top speed as well.


When I used to model in Excel, the resistance was modeled something like (1-0.995^n)*<weight> where n = # of loaded bearings. For most robots near the weight limit this falls between 5-6 lbs of resistance since only 4 wheels touch at a time.

This was really so I had some automated way to increase the resistance based upon weight and number of wheels hitting the floor rather than an accurate way to model it. It also provided a correlative model for what happened on our drive trains in 2008 & 2011, where the bearings had some binding due to improper mounting (thus the 0.995 was lower).