Author Topic: Robotic arm revolute joint design  (Read 1722 times)

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Offline murrdpirateTopic starter

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Robotic arm revolute joint design
« on: April 03, 2012, 09:42:59 PM »
I'm trying to make an elbow joint for a robotic arm that is actuated with a stepper motor and two gears.  Here's a quick sketch of what I'm trying to do:  http://imgur.com/mBlg7

The two bottom plates will be attached to the 'bicep' and the two upper plates will be attached to the 'forearm.'  The forearm pivots about the elbow shaft when the stepper motor rotates. 

In order to work, the elbow shaft has to be fixed to the upper two plates but free to rotate within the bottom plates.  Allowing it to rotate within the bottom plates is easy enough...could probably just provide large enough holes in the plates and let them act as bushings.  What I can't figure out is how to fix the shaft to the upper plates.  Anyone have any ideas?  Or maybe a better way to go about this entirely? 

Offline infurl

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Re: Robotic arm revolute joint design
« Reply #1 on: April 04, 2012, 01:56:05 AM »
Do you need to fix the elbow shaft to the upper plates? You only need to fix the second gear to the upper plates. So long as the shaft can't slip out of its bearings, it doesn't need to be attached to either set of plates.

Offline jkerns

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Re: Robotic arm revolute joint design
« Reply #2 on: April 04, 2012, 07:21:09 AM »
A bushing screwed to the upper plates with a set screw in a threaded hole or two to clamp on the shaft would work. You could buy a bushing or just get a chunk of aluminum and screw it into place before you drill the holes for the shaft.
 
I get paid to play with robots - can't beat that with a stick.

http://www.ltu.edu/engineering/mechanical/bachelor-science-robotics-engineering.asp

 


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