Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: Marauder_Pilot on January 23, 2008, 11:23:56 AM

Title: How powerful a stepper will I need?
Post by: Marauder_Pilot on January 23, 2008, 11:23:56 AM
One of my current projects needs a stepper motor that can rotate a roughly 6-8 pound (Still not 100% sure, so say 8 pound to be sure) aluminum container to a fairly precise degree. How powerful a stepper motor will I need to be able to control something like this?
Title: Re: How powerful a stepper will I need?
Post by: hazzer123 on January 23, 2008, 12:04:57 PM
Where on the aluminium container is the axis of rotation?

Could you please tell us a bit more about your problem. The shape of the container, desired speed of rotation, accuracy.
Title: Re: How powerful a stepper will I need?
Post by: Marauder_Pilot on January 23, 2008, 12:09:23 PM
Centered. The project in question is going to be an air cannon with a revolver-style drum. With each shot, the drum will rotate and bring up the next chamber (Filled with a nerf rocket or a paint grenade or a length of rope or whatever else I need/want to propel faster then I can throw). Speed, I'd like to be able to have them rotate in at most a second. Accuracy needs to be within a few degrees-whatever is in the chamber won't have to line up *perfectly* with the barrel every time, but the closer the better. (However, they'll likely be somewhat loose in the barrel, and probably with a degree of squishyness or in a sabot that will let them pass through minute differences in alignment between the barrel and the chamber).
Title: Re: How powerful a stepper will I need?
Post by: Admin on January 23, 2008, 12:14:17 PM
What you need to calculate is rotational torque, based on mass and moment of inertia.

You can find equations in google/wikipedia.

If you get stuck, post what you got and we can help you from there . . .