Testing stability of a model

[adam_widdowson]

Hello,

I am working on designing a mobile base for the UR10 robotic arm from Universal Robots. Whilst I am confident to use CAD to find the centre of mass, and maths to work out the moments whilst it is stationary, I understand that as the robotic arm moves the inertia will also affect the stability.

I have attached 2 images to demonstrate one of the movements which the robot would be doing with a very basic base (Final design will have a lot more to it than this).
Robot Position 1:

Robot Position 2:


I was wondering if there is a suitable CAD program to simulate the inertia of the arm & its role on the stability of the base? If not what would be the suitable equation to factor in intertia to the moments?

I keep coming across posts on various forums about working out moments whilst stationary, but nothing for moving objects....

Thanks
Adam W

[Kelly_Bramble]

Virtually ALL mainstream CAD programs provide Center of Mass location for a 3D model.

[Cake of Doom]

You could always work out the stationary 'worst case' moments and then apply a suitable dynamic factor to account for stop/start load increase. This should, at the very least, get you in the right ball park.

[adam_widdowson]

Virtually ALL mainstream CAD programs provide Center of Mass location for a 3D model.

''Whilst I am confident to use CAD to find the centre of mass, and maths to work out the moments whilst it is stationary, I understand that as the robotic arm moves the inertia will also affect the stability.''
As i said I understand this...

[adam_widdowson]

Thanks,
For the dynamic factor, would looking to the torque from the acceleration/deceleration of the arm and simply adding it to the staitionary moment be suitable as a ballpark estimate? Im not sure if the physics works like that (I understand that the pivot of the arm's motion is different to the pivot of the base tipping)....

Thanks!

[Kelly_Bramble]

Mass moment of inertia can be calculated from the center of mass... Most mainstream CAD/CAE software can do this.. Some CAD packages have an addon that can be purchased..

What CAD software do you run?

Also, see:

Mass Moment of Inertia Equations and Calculator

Thanks,
For the dynamic factor, would looking to the torque from the acceleration/deceleration of the arm and simply adding it to the staitionary moment be suitable as a ballpark estimate? Im not sure if the physics works like that (I understand that the pivot of the arm's motion is different to the pivot of the base tipping)....

Thanks!

[Cake of Doom]

What sort of holding down system did you have in mind?