Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: sw7 on March 20, 2012, 04:42:47 PM

Title: parts help
Post by: sw7 on March 20, 2012, 04:42:47 PM
My team and I are instructed to build a robot with 3 servos that only go 180 degrees. We are trying to build a crankshaft with all 3 servos. Right now we're using screws between 2 servo arms, but this is very unstable. Does anyone know where I can find a shaft that has the same 25-tooth spline as the servo itself, so that we can use it to attach 2 servo arms together, 1 at each end of the shaft?
Title: Re: parts help
Post by: Gertlex on March 21, 2012, 12:47:22 PM
You need to tell us what kind of servos you're using.

For coupling all three servos together, you might be best off using two brackets: one that holds the servos together, and a second that couples their output shafts/splines and the crankshaft.  The latter bracket would be something like this ( (but you'd probably need to build your own), but with an extension of some sort for the third servo and a further connection/extension to the crankshaft.

If you're using hobby servos, you're probably going to run into issues with the servos not quite having the exact same calibration (aka they'll go to slightly different angles given the same PWM pulse width.)