This tutorial is intended to complement the Robot Arm Torque Calculator found in the Dynamic Tools section of GoRobotics. The equations used in the calculator to determine the torque required at any given lifting joint (raising the arm vertically) in a robotic arm are presented h…

Thank you for replying!! Very helpful Yes the 0.5kg is the payload. Great, i’m gonna try to calculate the torque due to angular acceleration and then add it to the torque due to gravity? I’m guessing I will need to specify in how many seconds I would like the link to move up o…

Moving 45 degrees in one second doesn’t actually directly give you acceleration (radians per second per second) but rather the average angular speed. The harder part tends to be calculating the total inertia of the system.

Thank you, Total Inertia=Motor Inertia + Link Inertia, if i’m correct Does that mean I will already need to have motors selected? And then do the calculations

Effectively the inertia of each of the masses (and the support rod). Assuming the motor is not rotating at high speed (and it’s not a flywheel), its effect on the inertia is likely to be minimal so it’s up to you if you want to estimate it and include it. Remember, even with all …

So would I use this equation I=(m*r^2)/2 for each of the masses and add them together? (I’ve also seen some other equations for inertia online) I’m gonna be adding around 20% to my final calculations as the safety margin. I’m really appreciating your help!

When it comes to inertia formulae, it’s dependent on the shape, the rotation, where the weight is located etc. You’ll need to look it up for each unfortunately. Example

Ok great, thank you for all the help!

Hi again, small question, When calculating inertia let’s say for example I’m using the following equations from your tutorial and my diagram: I = (m*r^2)/2 [image] Would I take ‘r’ to be from the pivot point to the centre of each mass? e.g. if I’m calculating the inertia whe…

Note that the formula I = (m*r^2)/2 is associated with a disk rotating about the center, which is not the case in your drawing (no disk). You’ll likely be using the formula for a “rod”, “plank” or “satellite”. In inertia equations, “R” is associated with the object’s radius, wher…

Thank you, So I’ve completed the calculations for the joint, and found it to be around 19Nm (~15Nm + 20% for safety margin) How would i calculate the torque needed for the base motor? The motor is positioned as below: [image] To calculate the torque do I ignore the torque due…

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Robot Arm Torque Tutorial

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pk2902 February 16, 2022, 1:38pm 102

Ah I see, thank you for all the help!