Thread: Drive system calculations View Single Post
#4
09-02-2017, 07:34 PM
 Oblarg Registered User AKA: Eli Barnett FRC #0449 (The Blair Robot Project) Team Role: Mentor Join Date: Mar 2009 Rookie Year: 2008 Location: Philadelphia, PA Posts: 1,866
Re: Drive system calculations

Quote:
 Originally Posted by JSG1111 As of late I have been researching and trying to figure out calculations regarding the force required by a motor to move a robot that weighs 120 pounds. I understand torque and speed calculations and I can find how fast the wheels (6wd) will spin under no load but i'm not sure how to find how fast they will spin with 120lbs of material atop them.
In a frictionless system, the mass would not affect top speed at all, and only change how long it takes the robot to get there. Unfortunately, we don't build frictionless drive trains, and so this question boils down to "how much loss due to friction is there in a fully-loaded robot drive?" The answer to this is, unfortunately, "it's complicated" and your choices are basically to use an arbitrary fudge factor (most people use ~80%), or to test it empirically. Tools like the spreadsheet linked above do the former. The "correct" course of action is the latter.
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FRC Drivetrain Characterization