In FIG 8, function F represents the ideal shape of the surface to be machined, f represents the desired position generated by {TAIL ~ function generator} 142 and Y represents the actual position of {HEAD ~ cutting tool} 100 
In FIG 8 , function F represents the ideal shape of the surface to be machined , f represents the desired position generated by { TAIL ~ function generator } 142 and Y represents the actual position of { HEAD ~ cutting tool } 100
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH