How to Calculate Torque for a Robot Arm's Shoulder Joint?

[Mfrank7143]

Hi I am trying to designing a robot arm but am having problems calculating the torque required to drive the main shoulder joint.
The arm is 700mm long and weighs 3Kg with a mass on the moving end of 6Kg. The arm is required to rotate repeatedly through 180deg then reverse back to the starting point repeatedly at a rate of one return stroke in two seconds. Can anyone help with this?


Thank you.


Mike

 

[Rybose]

I don't have any practical experience with this, but your first step is to calculate the mass moment of inertia of the arm + the mass rotating about the pivot point.

Second, use your motion requirements calculate the required angular acceleration of the arm. T = I * alpha

Check out
www.electromate.com/technicalsupport/smartmotioncheatsheet.pdf

 

[Edpuente]

Hi I am trying to designing a robot arm but am having problems calculating the torque required to drive the main shoulder joint.
The arm is 700mm long and weighs 3Kg with a mass on the moving end of 6Kg. The arm is required to rotate repeatedly through 180deg then reverse back to the starting point repeatedly at a rate of one return stroke in two seconds. Can anyone help with this?


Thank you.


Mike

Do you have a lay out of the arm? Is the arm going to drop something? It is really necessary to stop it back and forth or can it move in a continuos path?

First thing besides knowing it´s moment of intertia you need to define a trayectorie of the speed you want the arm to make. What velocity and accelertion speed are you expecting to make, then from it you can stablish the torque needed and then you add the control to make the arm follow the velocity you stablished!


Velocity curve -> Torque required -> Control (Algorithm to follow the curve speed desired) or cam.