Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: Mahmoud on October 26, 2010, 12:44:55 PM
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i read robot arm article and it says that the moment of inertia of the arm is m*d^2 and i think it is supposed to be 1/3 m*d^2 because it is a rod rotating about its end
please can any one help me?
thanks in advance
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The moment of inertia can not be solved with either of them formulas .calculating mass moment of inertia requires integrals and is not easy unless you are a whiz at calculus .
Do you mean the moment around a point ?
The formula for this is M=f*d for example if you have a lever with a (d) 500 mm (0.5m) long and at the end of that lever you apply a force of 100N then the moment around the end of the lever is 0.5 *100 = 50N.m . also known as torque .
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1/3 ML^2 is correct
http://hyperphysics.phy-astr.gsu.edu/hbase/mi2.html (http://hyperphysics.phy-astr.gsu.edu/hbase/mi2.html)
The integral reduces to the above equation.
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ok then he writes wrongly or he has something else in his mind