6 dof arm robot kinematics and quaternions

[nowis]

Hi,

I have an 6 DOF hobby arm robot (wrist=3DOF). I want to program it with quaternions.
Because this has more advantages.

Can anyone tell me where good info is on the forward and inverse transformation ?
Or is there a way to work with quaternions and translations combined to do the kinematics ?

I have previously programmed the forward- and inverse kinematics of an 4 DOF arm
robot with matrices. See: http://www.lynxmotion.net/viewtopic.php?t=4452

Greetings

[Webbot]

Not quite sure what you are after - my problem!

Are you asking for a C quaternion library? Or just general info on quaternions? Or neither  ;