Per arm or the whole design?
Hmmm, I don't see why this can't be a direct drive. Is it a clearance issue with the other arms?
As the gear gets smaller, the movements from the motor get smaller and should increase accuracy. However I am assuming you mean this is countered because of the geometry of the four points change (having a hard time picturing it). That could also be adjusted for by moving the four points farther out, but that would come at the cost of movement range.
It might be a good idea to start with the required movement range and go backwards from there....
Hmmm, I don't see why this can't be a direct drive. Is it a clearance issue with the other arms?
As the gear gets smaller, the movements from the motor get smaller and should increase accuracy. However I am assuming you mean this is countered because of the geometry of the four points change (having a hard time picturing it). That could also be adjusted for by moving the four points farther out, but that would come at the cost of movement range.
It might be a good idea to start with the required movement range and go backwards from there....