{TAIL ~ A load force} feeds into {HEAD ~ a PID controller} programmed with preset proportional, differential and integral parameters 
{ TAIL ~ A load force } feeds into { HEAD ~ a PID controller } programmed with preset proportional , differential and integral parameters
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH