Scara Robot Manipulator Manual
Setup & Operation    4. Setting of End Effectors 
Calculating the Moment of Inertia 
Refer to the following examples of formulas to calculate the moment of inertia of load 
(end effector with work piece). 
The moment of inertia of the entire load is calculated by the sum of each part (a), (b), and 
(c). 
Work piece (b) 
Work piece (c) 
End effector (a) 
Joint #3 shaft 
Rotation center 
Moment of inertia 
of end effector (a)
= 
Moment of inertia 
of work piece (b)
+
Moment of inertia 
of work piece (c)
+
Whole moment 
of inertia 
The methods for calculating the moment of inertia for (a), (b), and (c) are shown below.   
Calculate the total moment of inertia using the basic formulas. 
(a) Moment of inertia of a rectangular parallelepiped 
b 
L 
Mass (m) 
Rectangular parallelepiped’s center of gravity 
Rotation center
m+ m × L
2
b
2
 + h
2
12 
h 
(b) Moment of inertia of a cylinder 
m+ m × L
2
r 
2
2
Mass (m)
L 
r
Cylinder’s center of gravity 
Rotation center 
44  G3 Rev.1 










