I need to use the parallel axis theorem to determine the moment of inertia of each robotic arm link referred to the joints of the 3 DOF manipulator. The moments of each link's centre of mass are:

enter image description here

The link joints are located according to the following coordinates from each link's centre of mass and the link masses are specified as:

enter image description here

I know that solve Izz, Iyy and Ixx to use the following equations:

Ixx = Ixx + m(ry^2 + rz^2)

Izz = Izz + m(rx^2 + ry^2)

Iyy = Iyy + m(rx^2 + rz^2)

But I'm not sure how to solve this particular problem, I was thinking since y1 and z1 both equal 0, to solve the question for that link I need to solve I1yy and I1zz is that right?


1 Answer 1


If the distance between the axes is zero, then there is no change in the inertia for that specific axis.

You can verify your calculations with a CAD software. Most of them (Solid Works, Inventor, Catia, etc.) can calculate the intertia of solid bodies in any defined reference frame (coordiante system).


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.