The device 6, wherein the means of detecting rotation parameters comprises {HEAD ~ a sensor} secured to {TAIL ~ the non rotating ring} and an encoder secured to the rotating ring 
secured to
The device 6 , wherein the means of detecting rotation parameters comprises { HEAD ~ a sensor } secured to { TAIL ~ the non rotating ring } and an encoder secured to the rotating ring
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH